Login | Register For Free | Help
Search for: (Advanced)

Mailing List Archive: Linux: Kernel

[RFC v2 1/2] PCI-Express Non-Transparent Bridge Support

 

 

Linux kernel RSS feed   Index | Next | Previous | View Threaded


jon.mason at intel

Jul 29, 2012, 5:26 PM

Post #1 of 20 (240 views)
Permalink
[RFC v2 1/2] PCI-Express Non-Transparent Bridge Support

A PCI-Express non-transparent bridge (NTB) is a point-to-point PCIe bus
connecting 2 systems, providing electrical isolation between the two subsystems.
A non-transparent bridge is functionally similar to a transparent bridge except
that both sides of the bridge have their own independent address domains. The
host on one side of the bridge will not have the visibility of the complete
memory or I/O space on the other side of the bridge. To communicate across the
non-transparent bridge, each NTB endpoint has one (or more) apertures exposed to
the local system. Writes to these apertures are mirrored to memory on the
remote system. Communications can also occur through the use of doorbell
registers that initiate interrupts to the alternate domain, and scratch-pad
registers accessible from both sides.

The NTB device driver is needed to configure these memory windows, doorbell, and
scratch-pad registers as well as use them in such a way as they can be turned
into a viable communication channel to the remote system. ntb_hw.[ch]
determines the usage model (NTB to NTB or NTB to Root Port) and abstracts away
the underlying hardware to provide access and a common interface to the doorbell
registers, scratch pads, and memory windows. These hardware interfaces are
exported so that other, non-mainlined kernel drivers can access these.
ntb_transport.[ch] also uses the exported interfaces in ntb_hw.[ch] to setup a
communication channel(s) and provide a reliable way of transferring data from
one side to the other, which it then exports so that "client" drivers can access
them. These client drivers are used to provide a standard kernel interface
(i.e., Ethernet device) to NTB, such that Linux can transfer data from one
system to the other in a standard way.

Signed-off-by: Jon Mason <jon.mason [at] intel>
---
MAINTAINERS | 6 +
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/ntb/Kconfig | 13 +
drivers/ntb/Makefile | 3 +
drivers/ntb/ntb_hw.c | 1178 ++++++++++++++++++++++++++++++++++++
drivers/ntb/ntb_hw.h | 206 +++++++
drivers/ntb/ntb_regs.h | 150 +++++
drivers/ntb/ntb_transport.c | 1387 +++++++++++++++++++++++++++++++++++++++++++
include/linux/ntb.h | 92 +++
10 files changed, 3038 insertions(+), 0 deletions(-)
create mode 100644 drivers/ntb/Kconfig
create mode 100644 drivers/ntb/Makefile
create mode 100644 drivers/ntb/ntb_hw.c
create mode 100644 drivers/ntb/ntb_hw.h
create mode 100644 drivers/ntb/ntb_regs.h
create mode 100644 drivers/ntb/ntb_transport.c
create mode 100644 include/linux/ntb.h

diff --git a/MAINTAINERS b/MAINTAINERS
index bd45164..9d57552 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4844,6 +4844,12 @@ S: Maintained
F: Documentation/scsi/NinjaSCSI.txt
F: drivers/scsi/nsp32*

+NTB DRIVER
+M: Jon Mason <jon.mason [at] intel>
+S: Supported
+F: drivers/ntb/
+F: include/linux/ntb.h
+
NTFS FILESYSTEM
M: Anton Altaparmakov <anton [at] tuxera>
L: linux-ntfs-dev [at] lists
diff --git a/drivers/Kconfig b/drivers/Kconfig
index bfc9186..ebc16d3 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -148,4 +148,6 @@ source "drivers/iio/Kconfig"

source "drivers/vme/Kconfig"

+source "drivers/ntb/Kconfig"
+
endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 2ba29ff..39bba94 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -137,3 +137,4 @@ obj-$(CONFIG_EXTCON) += extcon/
obj-$(CONFIG_MEMORY) += memory/
obj-$(CONFIG_IIO) += iio/
obj-$(CONFIG_VME_BUS) += vme/
+obj-$(CONFIG_NTB) += ntb/
diff --git a/drivers/ntb/Kconfig b/drivers/ntb/Kconfig
new file mode 100644
index 0000000..f69df793
--- /dev/null
+++ b/drivers/ntb/Kconfig
@@ -0,0 +1,13 @@
+config NTB
+ tristate "Intel Non-Transparent Bridge support"
+ depends on PCI
+ depends on X86
+ help
+ The PCI-E Non-transparent bridge hardware is a point-to-point PCI-E bus
+ connecting 2 systems. When configured, writes to the device's PCI
+ mapped memory will be mirrored to a buffer on the remote system. The
+ ntb Linux driver uses this point-to-point communication as a method to
+ transfer data from one system to the other.
+
+ If unsure, say N.
+
diff --git a/drivers/ntb/Makefile b/drivers/ntb/Makefile
new file mode 100644
index 0000000..15cb59f
--- /dev/null
+++ b/drivers/ntb/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_NTB) += ntb.o
+
+ntb-objs := ntb_hw.o ntb_transport.o
diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
new file mode 100644
index 0000000..11cb526
--- /dev/null
+++ b/drivers/ntb/ntb_hw.c
@@ -0,0 +1,1178 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license. When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ * The full GNU General Public License is included in this distribution
+ * in the file called LICENSE.GPL.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copy
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Intel PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Jon Mason <jon.mason [at] intel>
+ */
+#include <linux/debugfs.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include "ntb_hw.h"
+#include "ntb_regs.h"
+
+#define NTB_NAME "Intel(R) PCI-E Non-Transparent Bridge Driver"
+#define NTB_VER "0.21"
+
+MODULE_DESCRIPTION(NTB_NAME);
+MODULE_VERSION(NTB_VER);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Intel Corporation");
+
+enum {
+ NTB_CONN_CLASSIC = 0,
+ NTB_CONN_B2B,
+ NTB_CONN_RP,
+};
+
+enum {
+ NTB_DEV_USD = 0,
+ NTB_DEV_DSD,
+};
+
+enum {
+ SNB_HW = 0,
+ BWD_HW,
+};
+
+/* Translate memory window 0,1 to BAR 2,4 */
+#define MW_TO_BAR(mw) (mw * 2 + 2)
+
+static DEFINE_PCI_DEVICE_TABLE(ntb_pci_tbl) = {
+ {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_BWD)},
+ {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_JSF)},
+ {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_CLASSIC_JSF)},
+ {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_RP_JSF)},
+ {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_RP_SNB)},
+ {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_SNB)},
+ {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_CLASSIC_SNB)},
+ {0}
+};
+MODULE_DEVICE_TABLE(pci, ntb_pci_tbl);
+
+/**
+ * ntb_register_event_callback() - register event callback
+ * @ndev: pointer to ntb_device instance
+ * @func: callback function to register
+ *
+ * This function registers a callback for any HW driver events such as link
+ * up/down, power management notices and etc.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_register_event_callback(struct ntb_device *ndev,
+ void (*func)(void *handle, unsigned int event))
+{
+ if (ndev->event_cb)
+ return -EINVAL;
+
+ ndev->event_cb = func;
+
+ return 0;
+}
+
+/**
+ * ntb_unregister_event_callback() - unregisters the event callback
+ * @ndev: pointer to ntb_device instance
+ *
+ * This function unregisters the existing callback from transport
+ */
+void ntb_unregister_event_callback(struct ntb_device *ndev)
+{
+ ndev->event_cb = NULL;
+}
+
+/**
+ * ntb_register_db_callback() - register a callback for doorbell interrupt
+ * @ndev: pointer to ntb_device instance
+ * @idx: doorbell index to register callback, zero based
+ * @func: callback function to register
+ *
+ * This function registers a callback function for the doorbell interrupt
+ * on the primary side. The function will unmask the doorbell as well to
+ * allow interrupt.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_register_db_callback(struct ntb_device *ndev, unsigned int idx,
+ void *data, void (*func)(void *data, int db_num))
+{
+ unsigned long mask;
+
+ if (idx >= ndev->max_cbs || ndev->db_cb[idx].callback) {
+ dev_warn(&ndev->pdev->dev, "Invalid Index.\n");
+ return -EINVAL;
+ }
+
+ ndev->db_cb[idx].callback = func;
+ ndev->db_cb[idx].data = data;
+
+ /* unmask interrupt */
+ mask = readw(ndev->reg_ofs.pdb_mask);
+ clear_bit(idx * ndev->bits_per_vector, &mask);
+ writew(mask, ndev->reg_ofs.pdb_mask);
+
+ return 0;
+}
+
+/**
+ * ntb_unregister_db_callback() - unregister a callback for doorbell interrupt
+ * @ndev: pointer to ntb_device instance
+ * @idx: doorbell index to register callback, zero based
+ *
+ * This function unregisters a callback function for the doorbell interrupt
+ * on the primary side. The function will also mask the said doorbell.
+ */
+void ntb_unregister_db_callback(struct ntb_device *ndev, unsigned int idx)
+{
+ unsigned long mask;
+
+ if (idx >= ndev->max_cbs || !ndev->db_cb[idx].callback)
+ return;
+
+ mask = readw(ndev->reg_ofs.pdb_mask);
+ set_bit(idx * ndev->bits_per_vector, &mask);
+ writew(mask, ndev->reg_ofs.pdb_mask);
+
+ ndev->db_cb[idx].callback = NULL;
+}
+
+/**
+ * ntb_find_transport() - find the transport pointer
+ * @transport: pointer to pci device
+ *
+ * Given the pci device pointer, return the transport pointer passed in when
+ * the transport attached when it was inited.
+ *
+ * RETURNS: pointer to transport.
+ */
+void *ntb_find_transport(struct pci_dev *pdev)
+{
+ struct ntb_device *ndev = pci_get_drvdata(pdev);
+ return ndev->ntb_transport;
+}
+
+/**
+ * ntb_register_transport() - Register NTB transport with NTB HW driver
+ * @transport: transport identifier
+ *
+ * This function allows a transport to reserve the hardware driver for
+ * NTB usage.
+ *
+ * RETURNS: pointer to ntb_device, NULL on error.
+ */
+struct ntb_device *ntb_register_transport(struct pci_dev *pdev, void *transport)
+{
+ struct ntb_device *ndev = pci_get_drvdata(pdev);
+
+ if (ndev->ntb_transport)
+ return NULL;
+
+ ndev->ntb_transport = transport;
+ return ndev;
+}
+
+/**
+ * ntb_unregister_transport() - Unregister the transport with the NTB HW driver
+ * @ndev - ntb_device of the transport to be freed
+ *
+ * This function unregisters the transport from the HW driver and performs any
+ * necessary cleanups.
+ */
+void ntb_unregister_transport(struct ntb_device *ndev)
+{
+ int i;
+
+ if (!ndev->ntb_transport)
+ return;
+
+ for (i = 0; i < ndev->max_cbs; i++)
+ ntb_unregister_db_callback(ndev, i);
+
+ ntb_unregister_event_callback(ndev);
+ ndev->ntb_transport = NULL;
+}
+
+/**
+ * ntb_get_max_spads() - get the total scratch regs usable
+ * @ndev: pointer to ntb_device instance
+ *
+ * This function returns the max 32bit scratchpad registers usable by the
+ * upper layer.
+ *
+ * RETURNS: total number of scratch pad registers available
+ */
+int ntb_get_max_spads(struct ntb_device *ndev)
+{
+ return ndev->limits.max_spads;
+}
+
+/**
+ * ntb_write_local_spad() - write to the secondary scratchpad register
+ * @ndev: pointer to ntb_device instance
+ * @idx: index to the scratchpad register, 0 based
+ * @val: the data value to put into the register
+ *
+ * This function allows writing of a 32bit value to the indexed scratchpad
+ * register. The register resides on the secondary (external) side.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_write_local_spad(struct ntb_device *ndev, unsigned int idx, u32 val)
+{
+ if (idx >= ndev->limits.max_spads)
+ return -EINVAL;
+
+ dev_dbg(&ndev->pdev->dev, "Writing %x to local scratch pad index %d\n",
+ val, idx);
+ writel(val, ndev->reg_ofs.spad_read + idx * 4);
+
+ return 0;
+}
+
+/**
+ * ntb_read_local_spad() - read from the primary scratchpad register
+ * @ndev: pointer to ntb_device instance
+ * @idx: index to scratchpad register, 0 based
+ * @val: pointer to 32bit integer for storing the register value
+ *
+ * This function allows reading of the 32bit scratchpad register on
+ * the primary (internal) side.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_read_local_spad(struct ntb_device *ndev, unsigned int idx, u32 *val)
+{
+ if (idx >= ndev->limits.max_spads)
+ return -EINVAL;
+
+ *val = readl(ndev->reg_ofs.spad_write + idx * 4);
+ dev_dbg(&ndev->pdev->dev,
+ "Reading %x from local scratch pad index %d\n", *val, idx);
+
+ return 0;
+}
+
+/**
+ * ntb_write_remote_spad() - write to the secondary scratchpad register
+ * @ndev: pointer to ntb_device instance
+ * @idx: index to the scratchpad register, 0 based
+ * @val: the data value to put into the register
+ *
+ * This function allows writing of a 32bit value to the indexed scratchpad
+ * register. The register resides on the secondary (external) side.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_write_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 val)
+{
+ if (idx >= ndev->limits.max_spads)
+ return -EINVAL;
+
+ dev_dbg(&ndev->pdev->dev, "Writing %x to remote scratch pad index %d\n",
+ val, idx);
+ writel(val, ndev->reg_ofs.spad_write + idx * 4);
+
+ return 0;
+}
+
+/**
+ * ntb_read_remote_spad() - read from the primary scratchpad register
+ * @ndev: pointer to ntb_device instance
+ * @idx: index to scratchpad register, 0 based
+ * @val: pointer to 32bit integer for storing the register value
+ *
+ * This function allows reading of the 32bit scratchpad register on
+ * the primary (internal) side.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_read_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 *val)
+{
+ if (idx >= ndev->limits.max_spads)
+ return -EINVAL;
+
+ *val = readl(ndev->reg_ofs.spad_read + idx * 4);
+ dev_dbg(&ndev->pdev->dev,
+ "Reading %x from remote scratch pad index %d\n", *val, idx);
+
+ return 0;
+}
+
+/**
+ * ntb_get_mw_vbase() - get virtual addr for the NTB memory window
+ * @ndev: pointer to ntb_device instance
+ * @mw: memory window number
+ *
+ * This function provides the base virtual address of the memory window
+ * specified.
+ *
+ * RETURNS: pointer to virtual address, or NULL on error.
+ */
+void *ntb_get_mw_vbase(struct ntb_device *ndev, unsigned int mw)
+{
+ if (mw > NTB_NUM_MW)
+ return NULL;
+
+ return ndev->mw[mw].vbase;
+}
+
+/**
+ * ntb_get_mw_size() - return size of NTB memory window
+ * @ndev: pointer to ntb_device instance
+ * @mw: memory window number
+ *
+ * This function provides the physical size of the memory window specified
+ *
+ * RETURNS: the size of the memory window or zero on error
+ */
+resource_size_t ntb_get_mw_size(struct ntb_device *ndev, unsigned int mw)
+{
+ if (mw > NTB_NUM_MW)
+ return 0;
+
+ return ndev->mw[mw].bar_sz;
+}
+
+/**
+ * ntb_set_mw_addr - set the memory window address
+ * @ndev: pointer to ntb_device instance
+ * @mw: memory window number
+ * @addr: base address for data
+ *
+ * This function sets the base physical address of the memory window. This
+ * memory address is where data from the remote system will be transfered into
+ * or out of depending on how the transport is configured.
+ */
+void ntb_set_mw_addr(struct ntb_device *ndev, unsigned int mw, u64 addr)
+{
+ if (mw > NTB_NUM_MW)
+ return;
+
+ dev_dbg(&ndev->pdev->dev, "Writing addr %Lx to BAR %d\n", addr,
+ MW_TO_BAR(mw));
+
+ ndev->mw[mw].phys_addr = addr;
+
+ switch (MW_TO_BAR(mw)) {
+ case NTB_BAR_23:
+ writeq(addr, ndev->reg_ofs.sbar2_xlat);
+ break;
+ case NTB_BAR_45:
+ writeq(addr, ndev->reg_ofs.sbar4_xlat);
+ break;
+ }
+}
+
+/**
+ * ntb_ring_sdb() - Set the doorbell on the secondary/external side
+ * @ndev: pointer to ntb_device instance
+ * @db: doorbell to ring
+ *
+ * This function allows triggering of a doorbell on the secondary/external
+ * side that will initiate an interrupt on the remote host
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+void ntb_ring_sdb(struct ntb_device *ndev, unsigned int db)
+{
+ dev_dbg(&ndev->pdev->dev, "%s: ringing doorbell %d\n", __func__, db);
+
+ if (ndev->hw_type == BWD_HW)
+ writeq((u64) 1 << db, ndev->reg_ofs.sdb);
+ else
+ writew(((1 << ndev->bits_per_vector) - 1) <<
+ (db * ndev->bits_per_vector), ndev->reg_ofs.sdb);
+}
+
+static void ntb_link_event(struct ntb_device *ndev, int link_state)
+{
+ unsigned int event;
+
+ if (ndev->link_status == link_state)
+ return;
+
+ if (link_state == NTB_LINK_UP) {
+ u16 status;
+
+ dev_info(&ndev->pdev->dev, "Link Up\n");
+ ndev->link_status = NTB_LINK_UP;
+ event = NTB_EVENT_HW_LINK_UP;
+
+ if (ndev->hw_type == BWD_HW)
+ status = readw(ndev->reg_ofs.lnk_stat);
+ else {
+ int rc = pci_read_config_word(ndev->pdev,
+ SNB_LINK_STATUS_OFFSET,
+ &status);
+ if (rc)
+ return;
+ }
+ dev_info(&ndev->pdev->dev, "Link Width %d, Link Speed %d\n",
+ (status & NTB_LINK_WIDTH_MASK) >> 4,
+ (status & NTB_LINK_SPEED_MASK));
+ } else {
+ dev_info(&ndev->pdev->dev, "Link Down\n");
+ ndev->link_status = NTB_LINK_DOWN;
+ event = NTB_EVENT_HW_LINK_DOWN;
+ }
+
+ /* notify the upper layer if we have an event change */
+ if (ndev->event_cb)
+ ndev->event_cb(ndev->ntb_transport, event);
+}
+
+static int ntb_link_status(struct ntb_device *ndev)
+{
+ int link_state;
+
+ if (ndev->hw_type == BWD_HW) {
+ u32 ntb_cntl;
+
+ ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
+ if (ntb_cntl & BWD_CNTL_LINK_DOWN)
+ link_state = NTB_LINK_DOWN;
+ else
+ link_state = NTB_LINK_UP;
+ } else {
+ u16 status;
+ int rc;
+
+ rc = pci_read_config_word(ndev->pdev, SNB_LINK_STATUS_OFFSET,
+ &status);
+ if (rc)
+ return rc;
+
+ if (status & NTB_LINK_STATUS_ACTIVE)
+ link_state = NTB_LINK_UP;
+ else
+ link_state = NTB_LINK_DOWN;
+ }
+
+ ntb_link_event(ndev, link_state);
+
+ return 0;
+}
+
+/* BWD doesn't have link status interrupt, poll on that platform */
+static void ntb_handle_heartbeat(struct work_struct *work)
+{
+ struct ntb_device *ndev = container_of(work, struct ntb_device,
+ hb_timer.work);
+ unsigned long ts = jiffies;
+
+ /* If we haven't gotten an interrupt in a while, check the BWD link
+ * status bit
+ */
+ if (ts > ndev->last_ts + NTB_HB_TIMEOUT) {
+ int rc = ntb_link_status(ndev);
+ if (rc)
+ dev_err(&ndev->pdev->dev,
+ "Error determining link status\n");
+ }
+
+ schedule_delayed_work(&ndev->hb_timer, NTB_HB_TIMEOUT);
+}
+
+static int ntb_xeon_setup(struct ntb_device *ndev)
+{
+ int rc;
+ u8 val;
+
+ ndev->hw_type = SNB_HW;
+
+ rc = pci_read_config_byte(ndev->pdev, NTB_PPD_OFFSET, &val);
+ if (rc)
+ return rc;
+
+ switch (val & SNB_PPD_CONN_TYPE) {
+ case NTB_CONN_B2B:
+ ndev->conn_type = NTB_CONN_B2B;
+ break;
+ case NTB_CONN_CLASSIC:
+ case NTB_CONN_RP:
+ default:
+ dev_err(&ndev->pdev->dev, "Only B2B supported at this time\n");
+ return -EINVAL;
+ }
+
+ if (val & SNB_PPD_DEV_TYPE)
+ ndev->dev_type = NTB_DEV_DSD;
+ else
+ ndev->dev_type = NTB_DEV_USD;
+
+ ndev->reg_ofs.pdb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
+ ndev->reg_ofs.pdb_mask = ndev->reg_base + SNB_PDBMSK_OFFSET;
+ ndev->reg_ofs.sbar2_xlat = ndev->reg_base + SNB_SBAR2XLAT_OFFSET;
+ ndev->reg_ofs.sbar4_xlat = ndev->reg_base + SNB_SBAR4XLAT_OFFSET;
+ ndev->reg_ofs.lnk_cntl = ndev->reg_base + SNB_NTBCNTL_OFFSET;
+ ndev->reg_ofs.lnk_stat = ndev->reg_base + SNB_LINK_STATUS_OFFSET;
+ ndev->reg_ofs.spad_read = ndev->reg_base + SNB_SPAD_OFFSET;
+ ndev->reg_ofs.spci_cmd = ndev->reg_base + SNB_PCICMD_OFFSET;
+
+ if (ndev->conn_type == NTB_CONN_B2B) {
+ ndev->reg_ofs.sdb = ndev->reg_base + SNB_B2B_DOORBELL_OFFSET;
+ ndev->reg_ofs.spad_write = ndev->reg_base + SNB_B2B_SPAD_OFFSET;
+ ndev->limits.max_spads = SNB_MAX_SPADS;
+ } else {
+ ndev->reg_ofs.sdb = ndev->reg_base + SNB_SDOORBELL_OFFSET;
+ ndev->reg_ofs.spad_write = ndev->reg_base + SNB_SPAD_OFFSET;
+ ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS;
+ }
+
+ ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
+ ndev->limits.msix_cnt = SNB_MSIX_CNT;
+ ndev->bits_per_vector = SNB_DB_BITS_PER_VEC;
+
+ return 0;
+}
+
+static int ntb_bwd_setup(struct ntb_device *ndev)
+{
+ int rc;
+ u32 val;
+
+ ndev->hw_type = BWD_HW;
+
+ rc = pci_read_config_dword(ndev->pdev, NTB_PPD_OFFSET, &val);
+ if (rc)
+ return rc;
+
+ switch ((val & BWD_PPD_CONN_TYPE) >> 8) {
+ case NTB_CONN_B2B:
+ ndev->conn_type = NTB_CONN_B2B;
+ break;
+ case NTB_CONN_RP:
+ default:
+ dev_err(&ndev->pdev->dev, "Only B2B supported at this time\n");
+ return -EINVAL;
+ }
+
+ if (val & BWD_PPD_DEV_TYPE)
+ ndev->dev_type = NTB_DEV_DSD;
+ else
+ ndev->dev_type = NTB_DEV_USD;
+
+ /* Initiate PCI-E link training */
+ rc = pci_write_config_dword(ndev->pdev, NTB_PPD_OFFSET,
+ val | BWD_PPD_INIT_LINK);
+ if (rc)
+ return rc;
+
+ ndev->reg_ofs.pdb = ndev->reg_base + BWD_PDOORBELL_OFFSET;
+ ndev->reg_ofs.pdb_mask = ndev->reg_base + BWD_PDBMSK_OFFSET;
+ ndev->reg_ofs.sbar2_xlat = ndev->reg_base + BWD_SBAR2XLAT_OFFSET;
+ ndev->reg_ofs.sbar4_xlat = ndev->reg_base + BWD_SBAR4XLAT_OFFSET;
+ ndev->reg_ofs.lnk_cntl = ndev->reg_base + BWD_NTBCNTL_OFFSET;
+ ndev->reg_ofs.lnk_stat = ndev->reg_base + BWD_LINK_STATUS_OFFSET;
+ ndev->reg_ofs.spad_read = ndev->reg_base + BWD_SPAD_OFFSET;
+ ndev->reg_ofs.spci_cmd = ndev->reg_base + BWD_PCICMD_OFFSET;
+
+ if (ndev->conn_type == NTB_CONN_B2B) {
+ ndev->reg_ofs.sdb = ndev->reg_base + BWD_B2B_DOORBELL_OFFSET;
+ ndev->reg_ofs.spad_write = ndev->reg_base + BWD_B2B_SPAD_OFFSET;
+ ndev->limits.max_spads = BWD_MAX_SPADS;
+ } else {
+ ndev->reg_ofs.sdb = ndev->reg_base + BWD_PDOORBELL_OFFSET;
+ ndev->reg_ofs.spad_write = ndev->reg_base + BWD_SPAD_OFFSET;
+ ndev->limits.max_spads = BWD_MAX_COMPAT_SPADS;
+ }
+
+ ndev->limits.max_db_bits = BWD_MAX_DB_BITS;
+ ndev->limits.msix_cnt = BWD_MSIX_CNT;
+ ndev->bits_per_vector = BWD_DB_BITS_PER_VEC;
+
+ /* Since bwd doesn't have a link interrupt, setup a heartbeat timer */
+ INIT_DELAYED_WORK(&ndev->hb_timer, ntb_handle_heartbeat);
+ schedule_delayed_work(&ndev->hb_timer, NTB_HB_TIMEOUT);
+
+ return 0;
+}
+
+static int __devinit ntb_device_setup(struct ntb_device *ndev)
+{
+ int rc;
+
+ switch (ndev->pdev->device) {
+ case PCI_DEVICE_ID_INTEL_NTB_2ND_SNB:
+ case PCI_DEVICE_ID_INTEL_NTB_RP_JSF:
+ case PCI_DEVICE_ID_INTEL_NTB_RP_SNB:
+ case PCI_DEVICE_ID_INTEL_NTB_CLASSIC_JSF:
+ case PCI_DEVICE_ID_INTEL_NTB_CLASSIC_SNB:
+ case PCI_DEVICE_ID_INTEL_NTB_B2B_JSF:
+ case PCI_DEVICE_ID_INTEL_NTB_B2B_SNB:
+ rc = ntb_xeon_setup(ndev);
+ break;
+ case PCI_DEVICE_ID_INTEL_NTB_B2B_BWD:
+ rc = ntb_bwd_setup(ndev);
+ break;
+ default:
+ rc = -ENODEV;
+ }
+
+ /* Enable Bus Master and Memory Space on the secondary side */
+ writew(PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER, ndev->reg_ofs.spci_cmd);
+
+ return rc;
+}
+
+static void ntb_device_free(struct ntb_device *ndev)
+{
+ if (ndev->hw_type == BWD_HW)
+ cancel_delayed_work_sync(&ndev->hb_timer);
+}
+
+static irqreturn_t bwd_callback_msix_irq(int irq, void *data)
+{
+ struct ntb_db_cb *db_cb = data;
+ struct ntb_device *ndev = db_cb->ndev;
+
+ dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for DB %d\n", irq,
+ db_cb->db_num);
+
+ if (db_cb->callback)
+ db_cb->callback(db_cb->data, db_cb->db_num);
+
+ /* No need to check for the specific HB irq, any interrupt means
+ * we're connected.
+ */
+ ndev->last_ts = jiffies;
+
+ writeq((u64) 1 << db_cb->db_num, ndev->reg_ofs.pdb);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t xeon_callback_msix_irq(int irq, void *data)
+{
+ struct ntb_db_cb *db_cb = data;
+ struct ntb_device *ndev = db_cb->ndev;
+
+ dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for DB %d\n", irq,
+ db_cb->db_num);
+
+ if (db_cb->callback)
+ db_cb->callback(db_cb->data, db_cb->db_num);
+
+ /* On Sandybridge, there are 16 bits in the interrupt register
+ * but only 4 vectors. So, 5 bits are assigned to the first 3
+ * vectors, with the 4th having a single bit for link
+ * interrupts.
+ */
+ writew(((1 << ndev->bits_per_vector) - 1) <<
+ (db_cb->db_num * ndev->bits_per_vector), ndev->reg_ofs.pdb);
+
+ return IRQ_HANDLED;
+}
+
+/* Since we do not have a HW doorbell in BWD, this is only used in JF/JT */
+static irqreturn_t xeon_event_msix_irq(int irq, void *dev)
+{
+ struct ntb_device *ndev = dev;
+ int rc;
+
+ dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for Events\n", irq);
+
+ rc = ntb_link_status(ndev);
+ if (rc)
+ dev_err(&ndev->pdev->dev, "Error determining link status\n");
+
+ /* bit 15 is always the link bit */
+ writew(1 << ndev->limits.max_db_bits, ndev->reg_ofs.pdb);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t ntb_interrupt(int irq, void *dev)
+{
+ struct ntb_device *ndev = dev;
+ unsigned int i = 0;
+
+ if (ndev->hw_type == BWD_HW) {
+ u64 pdb = readq(ndev->reg_ofs.pdb);
+
+ dev_dbg(&ndev->pdev->dev, "irq %d - pdb = %Lx\n", irq, pdb);
+
+ while (pdb) {
+ i = __ffs(pdb);
+ pdb &= pdb - 1;
+ bwd_callback_msix_irq(irq, &ndev->db_cb[i]);
+ }
+ } else {
+ u16 pdb = readw(ndev->reg_ofs.pdb);
+
+ dev_dbg(&ndev->pdev->dev, "irq %d - pdb = %x sdb %x\n", irq,
+ pdb, readw(ndev->reg_ofs.sdb));
+
+ if (pdb & SNB_DB_HW_LINK) {
+ xeon_event_msix_irq(irq, dev);
+ pdb &= ~SNB_DB_HW_LINK;
+ }
+
+ while (pdb) {
+ i = __ffs(pdb);
+ pdb &= pdb - 1;
+ xeon_callback_msix_irq(irq, &ndev->db_cb[i]);
+ }
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int ntb_setup_msix(struct ntb_device *ndev)
+{
+ struct pci_dev *pdev = ndev->pdev;
+ struct msix_entry *msix;
+ int msix_entries;
+ int rc, i, pos;
+ u16 val;
+
+ pos = pci_find_capability(pdev, PCI_CAP_ID_MSIX);
+ if (!pos) {
+ rc = -EIO;
+ goto err;
+ }
+
+ rc = pci_read_config_word(pdev, pos + PCI_MSIX_FLAGS, &val);
+ if (rc)
+ goto err;
+
+ msix_entries = msix_table_size(val);
+ if (msix_entries > ndev->limits.msix_cnt) {
+ rc = -EINVAL;
+ goto err;
+ }
+
+ ndev->msix_entries = kmalloc(sizeof(struct msix_entry) * msix_entries,
+ GFP_KERNEL);
+ if (!ndev->msix_entries) {
+ rc = -ENOMEM;
+ goto err;
+ }
+
+ for (i = 0; i < msix_entries; i++)
+ ndev->msix_entries[i].entry = i;
+
+ rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
+ if (rc < 0)
+ goto err1;
+ if (rc > 0) {
+ /* On SNB, the link interrupt is always tied to 4th vector. If
+ * we can't get all 4, then we can't use MSI-X.
+ */
+ if (ndev->hw_type != BWD_HW) {
+ rc = -EIO;
+ goto err1;
+ }
+
+ dev_warn(&pdev->dev,
+ "Only %d MSI-X vectors. Limiting the number of queues to that number.\n",
+ rc);
+ msix_entries = rc;
+ }
+
+ for (i = 0; i < msix_entries; i++) {
+ msix = &ndev->msix_entries[i];
+ WARN_ON(!msix->vector);
+
+ /* Use the last MSI-X vector for Link status */
+ if (ndev->hw_type == BWD_HW) {
+ rc = request_irq(msix->vector, bwd_callback_msix_irq, 0,
+ "ntb-callback-msix", &ndev->db_cb[i]);
+ if (rc)
+ goto err2;
+ } else {
+ if (i == msix_entries - 1) {
+ rc = request_irq(msix->vector,
+ xeon_event_msix_irq, 0,
+ "ntb-event-msix", ndev);
+ if (rc)
+ goto err2;
+ } else {
+ rc = request_irq(msix->vector,
+ xeon_callback_msix_irq, 0,
+ "ntb-callback-msix",
+ &ndev->db_cb[i]);
+ if (rc)
+ goto err2;
+ }
+ }
+ }
+
+ ndev->num_msix = msix_entries;
+ if (ndev->hw_type == BWD_HW)
+ ndev->max_cbs = msix_entries;
+ else
+ ndev->max_cbs = msix_entries - 1;
+
+ return 0;
+
+err2:
+ while (--i >= 0) {
+ msix = &ndev->msix_entries[i];
+ if (ndev->hw_type != BWD_HW && i == ndev->num_msix - 1)
+ free_irq(msix->vector, ndev);
+ else
+ free_irq(msix->vector, &ndev->db_cb[i]);
+ }
+ pci_disable_msix(pdev);
+err1:
+ kfree(ndev->msix_entries);
+ dev_err(&pdev->dev, "Error allocating MSI-X interrupt\n");
+err:
+ ndev->num_msix = 0;
+ return rc;
+}
+
+static int ntb_setup_msi(struct ntb_device *ndev)
+{
+ struct pci_dev *pdev = ndev->pdev;
+ int rc;
+
+ rc = pci_enable_msi(pdev);
+ if (rc)
+ return rc;
+
+ rc = request_irq(pdev->irq, ntb_interrupt, 0, "ntb-msi", ndev);
+ if (rc) {
+ pci_disable_msi(pdev);
+ dev_err(&pdev->dev, "Error allocating MSI interrupt\n");
+ return rc;
+ }
+
+ return 0;
+}
+
+static int ntb_setup_intx(struct ntb_device *ndev)
+{
+ struct pci_dev *pdev = ndev->pdev;
+ int rc;
+
+ pci_msi_off(pdev);
+
+ /* Verify intx is enabled */
+ pci_intx(pdev, 1);
+
+ rc = request_irq(pdev->irq, ntb_interrupt, IRQF_SHARED, "ntb-intx",
+ ndev);
+ if (rc)
+ return rc;
+
+ return 0;
+}
+
+static int __devinit ntb_setup_interrupts(struct ntb_device *ndev)
+{
+ int rc;
+
+ /* On BWD, disable all interrupts. On SNB, disable all but Link
+ * Interrupt. The rest will be unmasked as callbacks are registered.
+ */
+ if (ndev->hw_type == BWD_HW)
+ writeq(~0, ndev->reg_ofs.pdb_mask);
+ else
+ writew(~(1 << ndev->limits.max_db_bits),
+ ndev->reg_ofs.pdb_mask);
+
+ rc = ntb_setup_msix(ndev);
+ if (!rc)
+ goto done;
+
+ ndev->bits_per_vector = 1;
+ ndev->max_cbs = ndev->limits.max_db_bits;
+
+ rc = ntb_setup_msi(ndev);
+ if (!rc)
+ goto done;
+
+ rc = ntb_setup_intx(ndev);
+ if (rc) {
+ dev_err(&ndev->pdev->dev, "no usable interrupts\n");
+ return rc;
+ }
+
+done:
+ return 0;
+}
+
+static void __devexit ntb_free_interrupts(struct ntb_device *ndev)
+{
+ struct pci_dev *pdev = ndev->pdev;
+
+ /* mask interrupts */
+ if (ndev->hw_type == BWD_HW)
+ writeq(~0, ndev->reg_ofs.pdb_mask);
+ else
+ writew(~0, ndev->reg_ofs.pdb_mask);
+
+ if (ndev->num_msix) {
+ struct msix_entry *msix;
+ u32 i;
+
+ for (i = 0; i < ndev->num_msix; i++) {
+ msix = &ndev->msix_entries[i];
+ if (ndev->hw_type != BWD_HW && i == ndev->num_msix - 1)
+ free_irq(msix->vector, ndev);
+ else
+ free_irq(msix->vector, &ndev->db_cb[i]);
+ }
+ pci_disable_msix(pdev);
+ } else {
+ free_irq(pdev->irq, ndev);
+
+ if (pci_dev_msi_enabled(pdev))
+ pci_disable_msi(pdev);
+ }
+}
+
+static int __devinit ntb_create_callbacks(struct ntb_device *ndev)
+{
+ int i;
+
+ /* Checken-egg issue. We won't know how many callbacks are necessary
+ * until we see how many MSI-X vectors we get, but these pointers need
+ * to be passed into the MSI-X register fucntion. So, we allocate the
+ * max, knowing that they might not all be used, to work around this.
+ */
+ ndev->db_cb = kcalloc(ndev->limits.max_db_bits,
+ sizeof(struct ntb_db_cb),
+ GFP_KERNEL);
+ if (!ndev->db_cb)
+ return -ENOMEM;
+
+ for (i = 0; i < ndev->limits.max_db_bits; i++) {
+ ndev->db_cb[i].db_num = i;
+ ndev->db_cb[i].ndev = ndev;
+ }
+
+ return 0;
+}
+
+static void ntb_free_callbacks(struct ntb_device *ndev)
+{
+ int i;
+
+ for (i = 0; i < ndev->limits.max_db_bits; i++)
+ ntb_unregister_db_callback(ndev, i);
+
+ kfree(ndev->db_cb);
+}
+
+static int __devinit
+ntb_pci_probe(struct pci_dev *pdev,
+ __attribute__((unused)) const struct pci_device_id *id)
+{
+ struct ntb_device *ndev;
+ int rc, i;
+
+ ndev = kzalloc(sizeof(struct ntb_device), GFP_KERNEL);
+ if (!ndev)
+ return -ENOMEM;
+
+ ndev->pdev = pdev;
+ ndev->link_status = NTB_LINK_DOWN;
+ pci_set_drvdata(pdev, ndev);
+
+ rc = pci_enable_device(pdev);
+ if (rc)
+ goto err;
+
+ pci_set_master(ndev->pdev);
+
+ rc = pci_request_selected_regions(pdev, NTB_BAR_MASK, KBUILD_MODNAME);
+ if (rc)
+ goto err1;
+
+ ndev->reg_base = pci_ioremap_bar(pdev, NTB_BAR_MMIO);
+ if (!ndev->reg_base) {
+ dev_warn(&pdev->dev, "Cannot remap BAR 0\n");
+ rc = -EIO;
+ goto err2;
+ }
+
+ for (i = 0; i < NTB_NUM_MW; i++) {
+ ndev->mw[i].bar_sz = pci_resource_len(pdev, MW_TO_BAR(i));
+ ndev->mw[i].vbase =
+ ioremap_wc(pci_resource_start(pdev, MW_TO_BAR(i)),
+ ndev->mw[i].bar_sz);
+ dev_info(&pdev->dev, "MW %d size %d\n", i,
+ (u32) pci_resource_len(pdev, MW_TO_BAR(i)));
+ if (!ndev->mw[i].vbase) {
+ dev_warn(&pdev->dev, "Cannot remap BAR %d\n",
+ MW_TO_BAR(i));
+ rc = -EIO;
+ goto err3;
+ }
+ }
+
+ rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(64));
+ if (rc) {
+ rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+ if (rc)
+ goto err3;
+
+ dev_warn(&pdev->dev, "Cannot DMA highmem\n");
+ }
+
+ rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
+ if (rc) {
+ rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
+ if (rc)
+ goto err3;
+
+ dev_warn(&pdev->dev, "Cannot DMA consistent highmem\n");
+ }
+
+ rc = ntb_device_setup(ndev);
+ if (rc)
+ goto err3;
+
+ rc = ntb_create_callbacks(ndev);
+ if (rc)
+ goto err4;
+
+ rc = ntb_setup_interrupts(ndev);
+ if (rc)
+ goto err5;
+
+ /* The scratchpad registers keep the values between rmmod/insmod,
+ * blast them now
+ */
+ for (i = 0; i < ndev->limits.max_spads; i++) {
+ ntb_write_local_spad(ndev, i, 0);
+ ntb_write_remote_spad(ndev, i, 0);
+ }
+
+ rc = ntb_transport_init(pdev);
+ if (rc)
+ goto err6;
+
+ /* Let's bring the NTB link up */
+ writel(NTB_CNTL_BAR23_SNOOP | NTB_CNTL_BAR45_SNOOP,
+ ndev->reg_ofs.lnk_cntl);
+
+ return 0;
+
+err6:
+ ntb_free_interrupts(ndev);
+err5:
+ ntb_free_callbacks(ndev);
+err4:
+ ntb_device_free(ndev);
+err3:
+ for (i--; i >= 0; i--)
+ iounmap(ndev->mw[i].vbase);
+ iounmap(ndev->reg_base);
+err2:
+ pci_release_selected_regions(pdev, NTB_BAR_MASK);
+err1:
+ pci_disable_device(pdev);
+err:
+ kfree(ndev);
+
+ dev_err(&pdev->dev, "Error loading %s module\n", KBUILD_MODNAME);
+ return rc;
+}
+
+static void __devexit ntb_pci_remove(struct pci_dev *pdev)
+{
+ struct ntb_device *ndev = pci_get_drvdata(pdev);
+ int i;
+ u32 ntb_cntl;
+
+ /* Bring NTB link down */
+ ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
+ ntb_cntl |= NTB_LINK_DISABLE;
+ writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);
+
+ ntb_transport_free(ndev->ntb_transport);
+
+ ntb_free_interrupts(ndev);
+ ntb_free_callbacks(ndev);
+ ntb_device_free(ndev);
+
+ for (i = 0; i < NTB_NUM_MW; i++)
+ iounmap(ndev->mw[i].vbase);
+
+ iounmap(ndev->reg_base);
+ pci_release_selected_regions(pdev, NTB_BAR_MASK);
+ pci_disable_device(pdev);
+ kfree(ndev);
+}
+
+static struct pci_driver ntb_pci_driver = {
+ .name = KBUILD_MODNAME,
+ .id_table = ntb_pci_tbl,
+ .probe = ntb_pci_probe,
+ .remove = __devexit_p(ntb_pci_remove),
+};
+
+static int __init ntb_init_module(void)
+{
+ pr_info("%s: %s, version %s\n", KBUILD_MODNAME, NTB_NAME, NTB_VER);
+
+ return pci_register_driver(&ntb_pci_driver);
+}
+module_init(ntb_init_module);
+
+static void __exit ntb_exit_module(void)
+{
+ pci_unregister_driver(&ntb_pci_driver);
+
+ pr_info("%s: Driver removed\n", KBUILD_MODNAME);
+}
+module_exit(ntb_exit_module);
diff --git a/drivers/ntb/ntb_hw.h b/drivers/ntb/ntb_hw.h
new file mode 100644
index 0000000..a1ddd77
--- /dev/null
+++ b/drivers/ntb/ntb_hw.h
@@ -0,0 +1,206 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license. When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ * The full GNU General Public License is included in this distribution
+ * in the file called LICENSE.GPL.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copy
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Intel PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Jon Mason <jon.mason [at] intel>
+ */
+
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_JSF 0x3725
+#define PCI_DEVICE_ID_INTEL_NTB_CLASSIC_JSF 0x3726
+#define PCI_DEVICE_ID_INTEL_NTB_RP_JSF 0x3727
+#define PCI_DEVICE_ID_INTEL_NTB_RP_SNB 0x3C08
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_SNB 0x3C0D
+#define PCI_DEVICE_ID_INTEL_NTB_CLASSIC_SNB 0x3C0E
+#define PCI_DEVICE_ID_INTEL_NTB_2ND_SNB 0x3C0F
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_BWD 0x0C4E
+
+#define msix_table_size(control) ((control & PCI_MSIX_FLAGS_QSIZE)+1)
+
+#define NTB_BAR_MMIO 0
+#define NTB_BAR_23 2
+#define NTB_BAR_45 4
+#define NTB_BAR_MASK ((1 << NTB_BAR_MMIO) | (1 << NTB_BAR_23) |\
+ (1 << NTB_BAR_45))
+
+#define NTB_LINK_DOWN 0
+#define NTB_LINK_UP 1
+
+#define NTB_HB_TIMEOUT msecs_to_jiffies(1000)
+
+#define NTB_NUM_MW 2
+
+enum ntb_hw_event {
+ NTB_EVENT_SW_EVENT0 = (1 << 0),
+ NTB_EVENT_SW_EVENT1 = (1 << 1),
+ NTB_EVENT_SW_EVENT2 = (1 << 2),
+ NTB_EVENT_HW_ERROR = (1 << 3),
+ NTB_EVENT_HW_LINK_UP = (1 << 4),
+ NTB_EVENT_HW_LINK_DOWN = (1 << 5),
+};
+
+struct ntb_mw {
+ dma_addr_t phys_addr;
+ void __iomem *vbase;
+ resource_size_t bar_sz;
+};
+
+struct ntb_db_cb {
+ void (*callback) (void *data, int db_num);
+ unsigned int db_num;
+ void *data;
+ struct ntb_device *ndev;
+};
+
+struct ntb_device {
+ struct pci_dev *pdev;
+ struct msix_entry *msix_entries;
+ void __iomem *reg_base;
+ struct ntb_mw mw[NTB_NUM_MW];
+ struct {
+ unsigned int max_spads;
+ unsigned int max_db_bits;
+ unsigned int msix_cnt;
+ } limits;
+ struct {
+ void __iomem *pdb;
+ void __iomem *pdb_mask;
+ void __iomem *sdb;
+ void __iomem *sbar2_xlat;
+ void __iomem *sbar4_xlat;
+ void __iomem *spad_write;
+ void __iomem *spad_read;
+ void __iomem *lnk_cntl;
+ void __iomem *lnk_stat;
+ void __iomem *spci_cmd;
+ } reg_ofs;
+ void *ntb_transport;
+ void (*event_cb)(void *handle, enum ntb_hw_event event);
+
+ struct ntb_db_cb *db_cb;
+ unsigned char hw_type;
+ unsigned char conn_type;
+ unsigned char dev_type;
+ unsigned char num_msix;
+ unsigned char bits_per_vector;
+ unsigned char max_cbs;
+ unsigned char link_status;
+ struct delayed_work hb_timer;
+ unsigned long last_ts;
+};
+
+/**
+ * ntb_hw_link_status() - return the hardware link status
+ * @ndev: pointer to ntb_device instance
+ *
+ * Returns true if the hardware is connected to the remote system
+ *
+ * RETURNS: true or false based on the hardware link state
+ */
+static inline bool ntb_hw_link_status(struct ntb_device *ndev)
+{
+ return ndev->link_status == NTB_LINK_UP;
+}
+
+/**
+ * ntb_query_pdev() - return the pci_dev pointer
+ * @ndev: pointer to ntb_device instance
+ *
+ * Given the ntb pointer return the pci_dev pointerfor the NTB hardware device
+ *
+ * RETURNS: a pointer to the ntb pci_dev
+ */
+static inline struct pci_dev *ntb_query_pdev(struct ntb_device *ndev)
+{
+ return ndev->pdev;
+}
+
+/**
+ * ntb_query_max_cbs() - return the maximum number of callback tuples
+ * @ndev: pointer to ntb_device instance
+ *
+ * The number of callbacks can vary depending on the platform and MSI-X/MSI
+ * enablement
+ *
+ * RETURNS: the maximum number of callback tuples (3, 15, or 33)
+ */
+static inline unsigned int ntb_query_max_cbs(struct ntb_device *ndev)
+{
+ return ndev->max_cbs;
+}
+
+struct ntb_device *ntb_register_transport(struct pci_dev *pdev,
+ void *transport);
+void ntb_unregister_transport(struct ntb_device *ndev);
+void ntb_set_mw_addr(struct ntb_device *ndev, unsigned int mw, u64 addr);
+int ntb_register_db_callback(struct ntb_device *ndev, unsigned int idx,
+ void *data, void (*db_cb_func) (void *data,
+ int db_num));
+void ntb_unregister_db_callback(struct ntb_device *ndev, unsigned int idx);
+int ntb_register_event_callback(struct ntb_device *ndev,
+ void (*event_cb_func) (void *handle,
+ unsigned int event));
+void ntb_unregister_event_callback(struct ntb_device *ndev);
+int ntb_get_max_spads(struct ntb_device *ndev);
+int ntb_write_local_spad(struct ntb_device *ndev, unsigned int idx, u32 val);
+int ntb_read_local_spad(struct ntb_device *ndev, unsigned int idx, u32 *val);
+int ntb_write_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 val);
+int ntb_read_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 *val);
+void *ntb_get_mw_vbase(struct ntb_device *ndev, unsigned int mw);
+resource_size_t ntb_get_mw_size(struct ntb_device *ndev, unsigned int mw);
+void ntb_ring_sdb(struct ntb_device *ndev, unsigned int idx);
+void *ntb_find_transport(struct pci_dev *pdev);
+
+int ntb_transport_init(struct pci_dev *pdev);
+void ntb_transport_free(void *transport);
diff --git a/drivers/ntb/ntb_regs.h b/drivers/ntb/ntb_regs.h
new file mode 100644
index 0000000..c7b8a24
--- /dev/null
+++ b/drivers/ntb/ntb_regs.h
@@ -0,0 +1,150 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license. When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ * The full GNU General Public License is included in this distribution
+ * in the file called LICENSE.GPL.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copy
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Intel PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Jon Mason <jon.mason [at] intel>
+ */
+
+#define NTB_LINK_ENABLE 0x0000
+#define NTB_LINK_DISABLE 0x0002
+#define NTB_LINK_STATUS_ACTIVE 0x2000
+#define NTB_LINK_SPEED_MASK 0x000f
+#define NTB_LINK_WIDTH_MASK 0x03f0
+
+#define SNB_MSIX_CNT 4
+#define SNB_MAX_SPADS 16
+#define SNB_MAX_COMPAT_SPADS 8
+/* Reserve the uppermost bit for link interrupt */
+#define SNB_MAX_DB_BITS 15
+#define SNB_DB_BITS_PER_VEC 5
+
+#define SNB_DB_HW_LINK 0x8000
+
+#define SNB_PCICMD_OFFSET 0x0504
+#define SNB_DEVCTRL_OFFSET 0x0598
+#define SNB_LINK_STATUS_OFFSET 0x01A2
+
+#define SNB_PBAR2LMT_OFFSET 0x0000
+#define SNB_PBAR4LMT_OFFSET 0x0008
+#define SNB_PBAR2XLAT_OFFSET 0x0010
+#define SNB_PBAR4XLAT_OFFSET 0x0018
+#define SNB_SBAR2LMT_OFFSET 0x0020
+#define SNB_SBAR4LMT_OFFSET 0x0028
+#define SNB_SBAR2XLAT_OFFSET 0x0030
+#define SNB_SBAR4XLAT_OFFSET 0x0038
+#define SNB_SBAR0BASE_OFFSET 0x0040
+#define SNB_SBAR2BASE_OFFSET 0x0048
+#define SNB_SBAR4BASE_OFFSET 0x0050
+#define SNB_NTBCNTL_OFFSET 0x0058
+#define SNB_SBDF_OFFSET 0x005C
+#define SNB_PDOORBELL_OFFSET 0x0060
+#define SNB_PDBMSK_OFFSET 0x0062
+#define SNB_SDOORBELL_OFFSET 0x0064
+#define SNB_SDBMSK_OFFSET 0x0066
+#define SNB_USMEMMISS 0x0070
+#define SNB_SPAD_OFFSET 0x0080
+#define SNB_SPADSEMA4_OFFSET 0x00c0
+#define SNB_WCCNTRL_OFFSET 0x00e0
+#define SNB_B2B_SPAD_OFFSET 0x0100
+#define SNB_B2B_DOORBELL_OFFSET 0x0140
+#define SNB_B2B_XLAT_OFFSET 0x0144
+
+#define BWD_MSIX_CNT 34
+#define BWD_MAX_SPADS 16
+#define BWD_MAX_COMPAT_SPADS 16
+#define BWD_MAX_DB_BITS 34
+#define BWD_DB_BITS_PER_VEC 1
+
+#define BWD_PCICMD_OFFSET 0xb004
+#define BWD_MBAR23_OFFSET 0xb018
+#define BWD_MBAR45_OFFSET 0xb020
+#define BWD_DEVCTRL_OFFSET 0xb048
+#define BWD_LINK_STATUS_OFFSET 0xb052
+
+#define BWD_SBAR2XLAT_OFFSET 0x0008
+#define BWD_SBAR4XLAT_OFFSET 0x0010
+#define BWD_PDOORBELL_OFFSET 0x0020
+#define BWD_PDBMSK_OFFSET 0x0028
+#define BWD_NTBCNTL_OFFSET 0x0060
+#define BWD_EBDF_OFFSET 0x0064
+#define BWD_SPAD_OFFSET 0x0080
+#define BWD_SPADSEMA_OFFSET 0x00c0
+#define BWD_STKYSPAD_OFFSET 0x00c4
+#define BWD_PBAR2XLAT_OFFSET 0x8008
+#define BWD_PBAR4XLAT_OFFSET 0x8010
+#define BWD_B2B_DOORBELL_OFFSET 0x8020
+#define BWD_B2B_SPAD_OFFSET 0x8080
+#define BWD_B2B_SPADSEMA_OFFSET 0x80c0
+#define BWD_B2B_STKYSPAD_OFFSET 0x80c4
+
+#define NTB_CNTL_BAR23_SNOOP (1 << 2)
+#define NTB_CNTL_BAR45_SNOOP (1 << 6)
+#define BWD_CNTL_LINK_DOWN (1 << 16)
+
+#define NTB_PPD_OFFSET 0x00D4
+#define SNB_PPD_CONN_TYPE 0x0003
+#define SNB_PPD_DEV_TYPE 0x0010
+#define BWD_PPD_INIT_LINK 0x0004
+#define BWD_PPD_CONN_TYPE 0x0300
+#define BWD_PPD_DEV_TYPE 0x1000
+
+#define BWD_PBAR2XLAT_USD_ADDR 0x0000004000000000
+#define BWD_PBAR4XLAT_USD_ADDR 0x0000008000000000
+#define BWD_MBAR23_USD_ADDR 0x000000410000000C
+#define BWD_MBAR45_USD_ADDR 0x000000810000000C
+#define BWD_PBAR2XLAT_DSD_ADDR 0x0000004100000000
+#define BWD_PBAR4XLAT_DSD_ADDR 0x0000008100000000
+#define BWD_MBAR23_DSD_ADDR 0x000000400000000C
+#define BWD_MBAR45_DSD_ADDR 0x000000800000000C
diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
new file mode 100644
index 0000000..6d152d3
--- /dev/null
+++ b/drivers/ntb/ntb_transport.c
@@ -0,0 +1,1387 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license. When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ * The full GNU General Public License is included in this distribution
+ * in the file called LICENSE.GPL.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copy
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Intel PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Jon Mason <jon.mason [at] intel>
+ */
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/ntb.h>
+#include "ntb_hw.h"
+
+static int transport_mtu = 0x4014;
+module_param(transport_mtu, uint, 0644);
+MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
+
+static unsigned int max_num_conns = 2;
+module_param(max_num_conns, uint, 0644);
+MODULE_PARM_DESC(max_num_conns, "Maximum number of NTB transport connections");
+
+struct ntb_queue_entry {
+ /* ntb_queue list reference */
+ struct list_head entry;
+ /* pointers to data to be transfered */
+ void *callback_data;
+ void *buf;
+ unsigned int len;
+ unsigned int flags;
+};
+
+struct ntb_transport;
+
+struct ntb_transport_qp {
+ struct ntb_transport *transport;
+ struct ntb_device *ndev;
+ void *cb_data;
+
+ bool client_ready;
+ bool qp_link;
+ u8 qp_num; /* Only 64 QP's are allowed. 0-63 */
+
+ void (*tx_handler) (void *data, struct ntb_transport_qp *qp);
+ struct tasklet_struct tx_work;
+ struct list_head tx_pend_q;
+ struct list_head tx_comp_q;
+ struct list_head tx_free_q;
+ spinlock_t ntb_tx_pend_q_lock;
+ spinlock_t ntb_tx_comp_q_lock;
+ spinlock_t ntb_tx_free_q_lock;
+ void *tx_mw_begin;
+ void *tx_mw_end;
+ void *tx_offset;
+
+ void (*rx_handler) (void *data, struct ntb_transport_qp *qp);
+ struct tasklet_struct rx_work;
+ struct list_head rx_pend_q;
+ struct list_head rx_comp_q;
+ struct list_head rx_free_q;
+ spinlock_t ntb_rx_pend_q_lock;
+ spinlock_t ntb_rx_comp_q_lock;
+ spinlock_t ntb_rx_free_q_lock;
+ void *rx_buff_begin;
+ void *rx_buff_end;
+ void *rx_offset;
+
+ void (*event_handler) (void *data, int status);
+ struct delayed_work link_work;
+
+ struct dentry *debugfs_dir;
+ struct dentry *debugfs_stats;
+
+ /* Stats */
+ u64 rx_bytes;
+ u64 rx_pkts;
+ u64 rx_ring_empty;
+ u64 rx_err_no_buf;
+ u64 rx_err_oflow;
+ u64 rx_err_ver;
+ u64 tx_bytes;
+ u64 tx_pkts;
+ u64 tx_ring_full;
+};
+
+struct ntb_transport_mw {
+ size_t size;
+ void *virt_addr;
+ dma_addr_t dma_addr;
+};
+
+struct ntb_transport {
+ struct ntb_device *ndev;
+ struct ntb_transport_mw mw[NTB_NUM_MW];
+ struct ntb_transport_qp *qps;
+ unsigned int max_qps;
+ unsigned long qp_bitmap;
+ bool transport_link;
+ struct delayed_work link_work;
+ struct dentry *debugfs_dir;
+ struct list_head list;
+};
+
+enum {
+ DESC_DONE_FLAG = 1 << 0,
+ LINK_DOWN_FLAG = 1 << 1,
+ HW_ERROR_FLAG = 1 << 2,
+};
+
+struct ntb_payload_header {
+ u64 ver;
+ unsigned int len;
+ unsigned int flags;
+};
+
+enum {
+ MW0_SZ = 0,
+ MW1_SZ,
+ NUM_QPS,
+ QP_LINKS,
+ MAX_SPAD,
+};
+
+#define QP_TO_MW(qp) ((qp) % NTB_NUM_MW)
+#define NTB_QP_DEF_NUM_ENTRIES 100
+#define NTB_LINK_DOWN_TIMEOUT 10
+
+static LIST_HEAD(ntb_transport_list);
+
+static int debugfs_open(struct inode *inode, struct file *filp)
+{
+ filp->private_data = inode->i_private;
+ return 0;
+}
+
+static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
+ loff_t *offp)
+{
+ struct ntb_transport_qp *qp;
+ char buf[512];
+ ssize_t ret, out_offset, out_count;
+
+ out_count = 512;
+
+ qp = filp->private_data;
+ out_offset = 0;
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "NTB Transport stats\n");
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_bytes - %llu\n", qp->rx_bytes);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_pkts - %llu\n", qp->rx_pkts);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_ring_empty - %llu\n", qp->rx_ring_empty);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_er_oflow - %llu\n", qp->rx_err_oflow);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_err_ver - %llu\n", qp->rx_err_ver);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_offset - %p\n", qp->rx_offset);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_bytes - %llu\n", qp->tx_bytes);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_pkts - %llu\n", qp->tx_pkts);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_ring_full - %llu\n", qp->tx_ring_full);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_offset - %p\n", qp->tx_offset);
+
+ ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
+ return ret;
+}
+
+static const struct file_operations ntb_qp_debugfs_stats = {
+ .owner = THIS_MODULE,
+ .open = debugfs_open,
+ .read = debugfs_read,
+};
+
+static void ntb_list_add_head(spinlock_t *lock, struct list_head *entry,
+ struct list_head *list)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(lock, flags);
+ list_add(entry, list);
+ spin_unlock_irqrestore(lock, flags);
+}
+
+static void ntb_list_add_tail(spinlock_t *lock, struct list_head *entry,
+ struct list_head *list)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(lock, flags);
+ list_add_tail(entry, list);
+ spin_unlock_irqrestore(lock, flags);
+}
+
+static struct ntb_queue_entry *ntb_list_rm_head(spinlock_t *lock,
+ struct list_head *list)
+{
+ struct ntb_queue_entry *entry;
+ unsigned long flags;
+
+ spin_lock_irqsave(lock, flags);
+ if (list_empty(list)) {
+ entry = NULL;
+ goto out;
+ }
+ entry = list_first_entry(list, struct ntb_queue_entry, entry);
+ list_del(&entry->entry);
+out:
+ spin_unlock_irqrestore(lock, flags);
+
+ return entry;
+}
+
+static int ntb_transport_setup_qp_mw(struct ntb_transport *nt,
+ unsigned int qp_num)
+{
+ struct ntb_transport_qp *qp = &nt->qps[qp_num];
+ u8 mw_num = QP_TO_MW(qp_num);
+ unsigned int size, num_qps_mw;
+
+ WARN_ON(nt->mw[mw_num].virt_addr == 0);
+
+ if (nt->max_qps % NTB_NUM_MW && !mw_num)
+ num_qps_mw = nt->max_qps / NTB_NUM_MW +
+ (nt->max_qps % NTB_NUM_MW - mw_num);
+ else
+ num_qps_mw = nt->max_qps / NTB_NUM_MW;
+
+ size = nt->mw[mw_num].size / num_qps_mw;
+ pr_debug("orig size = %d, num qps = %d, size = %d\n",
+ (int) nt->mw[mw_num].size, nt->max_qps, size);
+
+ qp->rx_buff_begin = nt->mw[mw_num].virt_addr +
+ (qp_num / NTB_NUM_MW * size);
+ qp->rx_buff_end = qp->rx_buff_begin + size;
+ pr_info("QP %d - RX Buff start %p end %p\n", qp->qp_num,
+ qp->rx_buff_begin, qp->rx_buff_end);
+ qp->rx_offset = qp->rx_buff_begin;
+
+ qp->tx_mw_begin = ntb_get_mw_vbase(nt->ndev, mw_num) +
+ (qp_num / NTB_NUM_MW * size);
+ qp->tx_mw_end = qp->tx_mw_begin + size;
+ pr_info("QP %d - TX MW start %p end %p\n", qp->qp_num, qp->tx_mw_begin,
+ qp->tx_mw_end);
+ qp->tx_offset = qp->tx_mw_begin;
+
+ qp->rx_pkts = 0;
+ qp->tx_pkts = 0;
+
+ return 0;
+}
+
+static int ntb_set_mw(struct ntb_transport *nt, int num_mw, unsigned int size)
+{
+ struct ntb_transport_mw *mw = &nt->mw[num_mw];
+ struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
+ void *offset;
+
+ /* Alloc memory for receiving data. Must be 4k aligned */
+ mw->size = ALIGN(size, 4096);
+
+ mw->virt_addr = dma_alloc_coherent(&pdev->dev, mw->size, &mw->dma_addr,
+ GFP_KERNEL);
+ if (!mw->virt_addr) {
+ pr_err("Unable to allocate MW buffer of size %d\n",
+ (int) mw->size);
+ return -ENOMEM;
+ }
+
+ /* setup the hdr offsets with 0's */
+ for (offset = mw->virt_addr;
+ offset + sizeof(struct ntb_payload_header) < mw->virt_addr + size;
+ offset += transport_mtu + sizeof(struct ntb_payload_header))
+ memset(offset, 0, sizeof(struct ntb_payload_header));
+
+ /* Notify HW the memory location of the receive buffer */
+ ntb_set_mw_addr(nt->ndev, num_mw, mw->dma_addr);
+
+ return 0;
+}
+
+static void ntb_transport_event_callback(void *data, enum ntb_hw_event event)
+{
+ struct ntb_transport *nt = data;
+
+ if (event == NTB_EVENT_HW_ERROR)
+ BUG();
+
+ if (event == NTB_EVENT_HW_LINK_UP)
+ schedule_delayed_work(&nt->link_work, 0);
+
+ if (event == NTB_EVENT_HW_LINK_DOWN) {
+ int i;
+
+ nt->transport_link = NTB_LINK_DOWN;
+
+ /* Pass along the info to any clients */
+ for (i = 0; i < nt->max_qps; i++)
+ if (!test_bit(i, &nt->qp_bitmap)) {
+ struct ntb_transport_qp *qp = &nt->qps[i];
+
+ if (qp->event_handler &&
+ qp->qp_link != NTB_LINK_DOWN)
+ qp->event_handler(qp->cb_data,
+ NTB_LINK_DOWN);
+
+ qp->qp_link = NTB_LINK_DOWN;
+ }
+
+ /* The scratchpad registers keep the values if the remote side
+ * goes down, blast them now to give them a sane value the next
+ * time they are accessed
+ */
+ for (i = 0; i < MAX_SPAD; i++) {
+ ntb_write_local_spad(nt->ndev, i, 0);
+ ntb_write_remote_spad(nt->ndev, i, 0);
+ }
+ }
+}
+
+static void ntb_transport_link_work(struct work_struct *work)
+{
+ struct ntb_transport *nt = container_of(work, struct ntb_transport,
+ link_work.work);
+ struct ntb_device *ndev = nt->ndev;
+ u32 val;
+ int rc, i;
+
+ /* send the local info */
+ rc = ntb_write_remote_spad(ndev, MW0_SZ, ntb_get_mw_size(ndev, 0));
+ if (rc) {
+ pr_err("Error writing %x to remote spad %d\n",
+ (u32) ntb_get_mw_size(ndev, 0), MW0_SZ);
+ goto out;
+ }
+
+ rc = ntb_write_remote_spad(ndev, MW1_SZ, ntb_get_mw_size(ndev, 1));
+ if (rc) {
+ pr_err("Error writing %x to remote spad %d\n",
+ (u32) ntb_get_mw_size(ndev, 1), MW1_SZ);
+ goto out;
+ }
+
+ rc = ntb_write_remote_spad(ndev, NUM_QPS, nt->max_qps);
+ if (rc) {
+ pr_err("Error writing %x to remote spad %d\n",
+ nt->max_qps, NUM_QPS);
+ goto out;
+ }
+
+ rc = ntb_write_remote_spad(ndev, QP_LINKS, 0);
+ if (rc) {
+ pr_err("Error writing %x to remote spad %d\n", 0, QP_LINKS);
+ goto out;
+ }
+
+ /* Query the remote side for its info */
+ rc = ntb_read_remote_spad(ndev, NUM_QPS, &val);
+ if (rc) {
+ pr_err("Error reading remote spad %d\n", NUM_QPS);
+ goto out;
+ }
+
+ if (val != nt->max_qps)
+ goto out;
+ pr_info("Remote max number of qps = %d\n", val);
+
+ rc = ntb_read_remote_spad(ndev, MW0_SZ, &val);
+ if (rc) {
+ pr_err("Error reading remote spad %d\n", MW0_SZ);
+ goto out;
+ }
+
+ if (!val)
+ goto out;
+ pr_info("Remote MW0 size = %d\n", val);
+
+ rc = ntb_set_mw(nt, 0, val);
+ if (rc)
+ goto out;
+
+ rc = ntb_read_remote_spad(ndev, MW1_SZ, &val);
+ if (rc) {
+ pr_err("Error reading remote spad %d\n", MW1_SZ);
+ goto out;
+ }
+
+ if (!val)
+ goto out;
+ pr_info("Remote MW1 size = %d\n", val);
+
+ rc = ntb_set_mw(nt, 1, val);
+ if (rc)
+ goto out;
+
+ for (i = 0; i < nt->max_qps; i++) {
+ struct ntb_transport_qp *qp = &nt->qps[i];
+
+ rc = ntb_transport_setup_qp_mw(nt, i);
+ if (rc)
+ goto out;
+
+ if (qp->client_ready)
+ schedule_delayed_work(&qp->link_work, 0);
+ }
+
+ nt->transport_link = NTB_LINK_UP;
+
+ return;
+
+out:
+ if (ntb_hw_link_status(ndev))
+ schedule_delayed_work(&nt->link_work,
+ msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+}
+
+static void ntb_qp_link_work(struct work_struct *work)
+{
+ struct ntb_transport_qp *qp;
+ struct ntb_transport *nt;
+ int rc, val;
+
+ qp = container_of(work, struct ntb_transport_qp, link_work.work);
+ nt = qp->transport;
+
+ WARN_ON(nt->transport_link != NTB_LINK_UP);
+
+ rc = ntb_read_local_spad(nt->ndev, QP_LINKS, &val);
+ if (rc) {
+ pr_err("Error reading spad %d\n", QP_LINKS);
+ return;
+ }
+
+ rc = ntb_write_remote_spad(nt->ndev, QP_LINKS, val | 1 << qp->qp_num);
+ if (rc)
+ pr_err("Error writing %x to remote spad %d\n",
+ val | 1 << qp->qp_num, QP_LINKS);
+
+ /* query remote spad for qp ready bits */
+ rc = ntb_read_remote_spad(nt->ndev, QP_LINKS, &val);
+ if (rc)
+ pr_err("Error reading remote spad %d\n", QP_LINKS);
+
+ pr_debug("Remote QP link status = %x\n", val);
+
+ /* See if the remote side is up */
+ if (1 << qp->qp_num & val) {
+ qp->qp_link = NTB_LINK_UP;
+
+ if (qp->event_handler)
+ qp->event_handler(qp->cb_data, NTB_LINK_UP);
+ } else if (ntb_hw_link_status(nt->ndev))
+ schedule_delayed_work(&qp->link_work,
+ msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+}
+
+static void ntb_transport_init_queue(struct ntb_transport *nt,
+ unsigned int qp_num)
+{
+ struct ntb_transport_qp *qp;
+
+ qp = &nt->qps[qp_num];
+ qp->qp_num = qp_num;
+ qp->transport = nt;
+ qp->ndev = nt->ndev;
+ qp->qp_link = NTB_LINK_DOWN;
+
+ if (nt->debugfs_dir) {
+ char debugfs_name[4];
+
+ snprintf(debugfs_name, 4, "qp%d", qp_num);
+ qp->debugfs_dir = debugfs_create_dir(debugfs_name,
+ nt->debugfs_dir);
+
+ qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
+ qp->debugfs_dir, qp,
+ &ntb_qp_debugfs_stats);
+ }
+
+ INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
+
+ spin_lock_init(&qp->ntb_rx_comp_q_lock);
+ spin_lock_init(&qp->ntb_rx_pend_q_lock);
+ spin_lock_init(&qp->ntb_rx_free_q_lock);
+ spin_lock_init(&qp->ntb_tx_comp_q_lock);
+ spin_lock_init(&qp->ntb_tx_pend_q_lock);
+ spin_lock_init(&qp->ntb_tx_free_q_lock);
+
+ INIT_LIST_HEAD(&qp->rx_pend_q);
+ INIT_LIST_HEAD(&qp->rx_comp_q);
+ INIT_LIST_HEAD(&qp->rx_free_q);
+ INIT_LIST_HEAD(&qp->tx_pend_q);
+ INIT_LIST_HEAD(&qp->tx_comp_q);
+ INIT_LIST_HEAD(&qp->tx_free_q);
+}
+
+int ntb_transport_init(struct pci_dev *pdev)
+{
+ struct ntb_transport *nt;
+ int rc, i;
+
+ nt = kzalloc(sizeof(struct ntb_transport), GFP_KERNEL);
+ if (!nt)
+ return -ENOMEM;
+
+ if (debugfs_initialized())
+ nt->debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+ else
+ nt->debugfs_dir = NULL;
+
+ nt->ndev = ntb_register_transport(pdev, nt);
+ if (!nt->ndev) {
+ rc = -EIO;
+ goto err;
+ }
+
+ nt->max_qps = ntb_query_max_cbs(nt->ndev);
+ if (!nt->max_qps) {
+ rc = -EIO;
+ goto err1;
+ }
+ nt->max_qps = min(nt->max_qps, max_num_conns);
+
+ nt->qps = kcalloc(nt->max_qps, sizeof(struct ntb_transport_qp),
+ GFP_KERNEL);
+ if (!nt->qps) {
+ rc = -ENOMEM;
+ goto err1;
+ }
+
+ nt->qp_bitmap = ((u64) 1 << nt->max_qps) - 1;
+
+ for (i = 0; i < nt->max_qps; i++)
+ ntb_transport_init_queue(nt, i);
+
+ rc = ntb_register_event_callback(nt->ndev,
+ ntb_transport_event_callback);
+ if (rc)
+ goto err2;
+
+ list_add(&nt->list, &ntb_transport_list);
+
+ INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
+
+ if (ntb_hw_link_status(nt->ndev))
+ schedule_delayed_work(&nt->link_work, 0);
+
+ return 0;
+
+err2:
+ kfree(nt->qps);
+err1:
+ ntb_unregister_transport(nt->ndev);
+err:
+ debugfs_remove_recursive(nt->debugfs_dir);
+ kfree(nt);
+ return rc;
+}
+
+void ntb_transport_free(void *transport)
+{
+ struct ntb_transport *nt = transport;
+ struct pci_dev *pdev;
+ int i;
+
+ nt->transport_link = NTB_LINK_DOWN;
+
+ /* verify that all the qp's are freed */
+ while (!nt->qp_bitmap) {
+ i = ffz(nt->qp_bitmap);
+ if (i == ((u64) 1 << nt->max_qps))
+ break;
+ ntb_transport_free_queue(&nt->qps[i]);
+ }
+
+ list_del(&nt->list);
+
+ cancel_delayed_work_sync(&nt->link_work);
+
+ debugfs_remove_recursive(nt->debugfs_dir);
+
+ ntb_unregister_event_callback(nt->ndev);
+
+ pdev = ntb_query_pdev(nt->ndev);
+
+ for (i = 0; i < NTB_NUM_MW; i++)
+ if (nt->mw[i].virt_addr)
+ dma_free_coherent(&pdev->dev, nt->mw[i].size,
+ nt->mw[i].virt_addr,
+ nt->mw[i].dma_addr);
+
+ kfree(nt->qps);
+ ntb_unregister_transport(nt->ndev);
+ kfree(nt);
+}
+
+static void ntb_rx_copy_task(struct ntb_transport_qp *qp,
+ struct ntb_queue_entry *entry, void *offset)
+{
+ struct ntb_payload_header *hdr = offset;
+
+ entry->len = hdr->len;
+ offset += sizeof(struct ntb_payload_header);
+ memcpy(entry->buf, offset, entry->len);
+
+ /* Ensure that the data is fully copied out before clearing the flag */
+ wmb();
+ hdr->flags = 0;
+ ntb_list_add_tail(&qp->ntb_rx_comp_q_lock, &entry->entry,
+ &qp->rx_comp_q);
+
+ if (qp->rx_handler && qp->client_ready)
+ qp->rx_handler(qp->cb_data, qp);
+}
+
+static int ntb_process_rxc(struct ntb_transport_qp *qp)
+{
+ struct ntb_payload_header *hdr;
+ struct ntb_queue_entry *entry;
+ void *offset;
+
+ entry = ntb_list_rm_head(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
+ if (!entry) {
+ hdr = qp->rx_offset;
+ pr_debug("no buffer - HDR ver %llu, len %d, flags %x\n",
+ hdr->ver, hdr->len, hdr->flags);
+ qp->rx_err_no_buf++;
+ return -ENOMEM;
+ }
+
+ offset = qp->rx_offset;
+ hdr = offset;
+
+ if (!(hdr->flags & DESC_DONE_FLAG)) {
+ ntb_list_add_tail(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+ qp->rx_ring_empty++;
+ return -EAGAIN;
+ }
+
+ if (hdr->ver != qp->rx_pkts) {
+ pr_debug("qp %d: version mismatch, expected %llu - got %llu\n",
+ qp->qp_num, qp->rx_pkts, hdr->ver);
+ ntb_list_add_tail(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+ qp->rx_err_ver++;
+ return -EIO;
+ }
+
+ if (hdr->flags & NTB_LINK_DOWN) {
+ pr_info("qp %d: Link Down\n", qp->qp_num);
+ qp->qp_link = NTB_LINK_DOWN;
+ schedule_delayed_work(&qp->link_work,
+ msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+
+ if (qp->event_handler)
+ qp->event_handler(qp->cb_data, NTB_LINK_DOWN);
+
+ ntb_list_add_tail(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+
+ /* Ensure that the data is fully copied out before clearing the
+ * done flag
+ */
+ wmb();
+ hdr->flags = 0;
+ goto out;
+ }
+
+ pr_debug("rx offset %p, ver %llu - %d payload received, buf size %d\n",
+ qp->rx_offset, hdr->ver, hdr->len, entry->len);
+
+ if (hdr->len <= entry->len)
+ ntb_rx_copy_task(qp, entry, offset);
+ else {
+ ntb_list_add_tail(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+
+ /* Ensure that the data is fully copied out before clearing the
+ * done flag
+ */
+ wmb();
+ hdr->flags = 0;
+ qp->rx_err_oflow++;
+ pr_err("RX overflow! Wanted %d got %d\n", hdr->len, entry->len);
+ }
+
+ qp->rx_bytes += hdr->len;
+ qp->rx_pkts++;
+
+out:
+ qp->rx_offset =
+ (qp->rx_offset +
+ ((transport_mtu + sizeof(struct ntb_payload_header)) * 2) >=
+ qp->rx_buff_end) ? qp->rx_buff_begin : qp->rx_offset +
+ transport_mtu + sizeof(struct ntb_payload_header);
+
+ return 0;
+}
+
+static void ntb_transport_rx(unsigned long data)
+{
+ struct ntb_transport_qp *qp = (struct ntb_transport_qp *)data;
+ int rc;
+
+ do {
+ rc = ntb_process_rxc(qp);
+ } while (!rc);
+}
+
+static void ntb_transport_rxc_db(void *data, int db_num)
+{
+ struct ntb_transport_qp *qp = data;
+
+ pr_debug("%s: doorbell %d received\n", __func__, db_num);
+
+ tasklet_schedule(&qp->rx_work);
+}
+
+static void ntb_tx_copy_task(struct ntb_transport_qp *qp,
+ struct ntb_queue_entry *entry,
+ void *offset)
+{
+ struct ntb_payload_header *hdr = offset;
+
+ offset += sizeof(struct ntb_payload_header);
+ memcpy_toio(offset, entry->buf, entry->len);
+
+ hdr->len = entry->len;
+ hdr->ver = qp->tx_pkts;
+
+ /* Ensure that the data is fully copied out before setting the flag */
+ wmb();
+ hdr->flags = entry->flags | DESC_DONE_FLAG;
+
+ ntb_ring_sdb(qp->ndev, qp->qp_num);
+
+ /* The entry length can only be zero if the packet is intended to be a
+ * "link down" or similar. Since no payload is being sent in these
+ * cases, there is nothing to add to the completion queue.
+ */
+ if (entry->len > 0) {
+ qp->tx_bytes += entry->len;
+
+ /* Add fully transmitted data to completion queue */
+ ntb_list_add_tail(&qp->ntb_tx_comp_q_lock, &entry->entry,
+ &qp->tx_comp_q);
+
+ if (qp->tx_handler)
+ qp->tx_handler(qp->cb_data, qp);
+ } else
+ ntb_list_add_tail(&qp->ntb_tx_free_q_lock, &entry->entry,
+ &qp->tx_free_q);
+}
+
+static int ntb_process_tx(struct ntb_transport_qp *qp,
+ struct ntb_queue_entry *entry)
+{
+ struct ntb_payload_header *hdr;
+ void *offset;
+
+ offset = qp->tx_offset;
+ hdr = offset;
+
+ pr_debug("%lld - offset %p, tx %p, entry len %d flags %x buff %p\n",
+ qp->tx_pkts, offset, qp->tx_offset, entry->len, entry->flags,
+ entry->buf);
+ if (hdr->flags) {
+ ntb_list_add_head(&qp->ntb_tx_pend_q_lock, &entry->entry,
+ &qp->tx_pend_q);
+ qp->tx_ring_full++;
+ return -EAGAIN;
+ }
+
+ if (entry->len > transport_mtu) {
+ pr_err("Trying to send pkt size of %d\n", entry->len);
+ entry->flags = HW_ERROR_FLAG;
+
+ ntb_list_add_tail(&qp->ntb_tx_comp_q_lock, &entry->entry,
+ &qp->tx_comp_q);
+
+ if (qp->tx_handler)
+ qp->tx_handler(qp->cb_data, qp);
+
+ return 0;
+ }
+
+ ntb_tx_copy_task(qp, entry, offset);
+
+ qp->tx_offset =
+ (qp->tx_offset +
+ ((transport_mtu + sizeof(struct ntb_payload_header)) * 2) >=
+ qp->tx_mw_end) ? qp->tx_mw_begin : qp->tx_offset + transport_mtu +
+ sizeof(struct ntb_payload_header);
+
+ qp->tx_pkts++;
+
+ return 0;
+}
+
+static void ntb_transport_tx(unsigned long data)
+{
+ struct ntb_transport_qp *qp = (struct ntb_transport_qp *)data;
+ struct ntb_queue_entry *entry;
+ int rc;
+
+ do {
+ entry = ntb_list_rm_head(&qp->ntb_tx_pend_q_lock,
+ &qp->tx_pend_q);
+ if (!entry)
+ break;
+
+ rc = ntb_process_tx(qp, entry);
+ } while (!rc);
+}
+
+static void ntb_send_link_down(struct ntb_transport_qp *qp)
+{
+ struct ntb_queue_entry *entry;
+ int i;
+
+ if (qp->qp_link == NTB_LINK_DOWN)
+ return;
+
+ qp->qp_link = NTB_LINK_DOWN;
+
+ for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
+ entry = ntb_list_rm_head(&qp->ntb_tx_free_q_lock,
+ &qp->tx_free_q);
+ if (entry)
+ break;
+ msleep(100);
+ }
+
+ entry->callback_data = NULL;
+ entry->buf = NULL;
+ entry->len = 0;
+ entry->flags = LINK_DOWN_FLAG;
+
+ ntb_list_add_tail(&qp->ntb_tx_pend_q_lock, &entry->entry,
+ &qp->tx_pend_q);
+ tasklet_schedule(&qp->tx_work);
+}
+
+/**
+ * ntb_transport_create_queue - Create a new NTB transport layer queue
+ * @rx_handler: receive callback function
+ * @tx_handler: transmit callback function
+ * @event_handler: event callback function
+ *
+ * Create a new NTB transport layer queue and provide the queue with a callback
+ * routine for both transmit and receive. The receive callback routine will be
+ * used to pass up data when the transport has received it on the queue. The
+ * transmit callback routine will be called when the transport has completed the
+ * transmission of the data on the queue and the data is ready to be freed.
+ *
+ * RETURNS: pointer to newly created ntb_queue, NULL on error.
+ */
+struct ntb_transport_qp *
+ntb_transport_create_queue(void *data, struct pci_dev *pdev,
+ const struct ntb_queue_handlers *handlers)
+{
+ struct ntb_queue_entry *entry;
+ struct ntb_transport_qp *qp;
+ struct ntb_transport *nt;
+ unsigned int free_queue;
+ int rc, i;
+
+ nt = ntb_find_transport(pdev);
+ if (!nt)
+ goto err;
+
+ free_queue = ffs(nt->qp_bitmap);
+ if (!free_queue)
+ goto err;
+
+ /* decrement free_queue to make it zero based */
+ free_queue--;
+
+ clear_bit(free_queue, &nt->qp_bitmap);
+
+ qp = &nt->qps[free_queue];
+ qp->cb_data = data;
+ qp->rx_handler = handlers->rx_handler;
+ qp->tx_handler = handlers->tx_handler;
+ qp->event_handler = handlers->event_handler;
+
+ for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
+ entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
+ if (!entry)
+ goto err1;
+
+ ntb_list_add_tail(&qp->ntb_rx_free_q_lock, &entry->entry,
+ &qp->rx_free_q);
+ }
+
+ for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
+ entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
+ if (!entry)
+ goto err2;
+
+ ntb_list_add_tail(&qp->ntb_tx_free_q_lock, &entry->entry,
+ &qp->tx_free_q);
+ }
+
+ tasklet_init(&qp->rx_work, ntb_transport_rx, (unsigned long) qp);
+ tasklet_init(&qp->tx_work, ntb_transport_tx, (unsigned long) qp);
+
+ rc = ntb_register_db_callback(qp->ndev, free_queue, qp,
+ ntb_transport_rxc_db);
+ if (rc)
+ goto err3;
+
+ pr_info("NTB Transport QP %d created\n", qp->qp_num);
+
+ return qp;
+
+err3:
+ tasklet_disable(&qp->rx_work);
+ tasklet_disable(&qp->tx_work);
+err2:
+ while ((entry =
+ ntb_list_rm_head(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
+ kfree(entry);
+err1:
+ while ((entry =
+ ntb_list_rm_head(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
+ kfree(entry);
+ set_bit(free_queue, &nt->qp_bitmap);
+err:
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
+
+/**
+ * ntb_transport_free_queue - Frees NTB transport queue
+ * @qp: NTB queue to be freed
+ *
+ * Frees NTB transport queue
+ */
+void ntb_transport_free_queue(struct ntb_transport_qp *qp)
+{
+ struct ntb_queue_entry *entry;
+
+ if (!qp)
+ return;
+
+ cancel_delayed_work_sync(&qp->link_work);
+
+ ntb_unregister_db_callback(qp->ndev, qp->qp_num);
+ tasklet_disable(&qp->rx_work);
+ tasklet_disable(&qp->tx_work);
+
+ while ((entry =
+ ntb_list_rm_head(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
+ kfree(entry);
+
+ while ((entry =
+ ntb_list_rm_head(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q))) {
+ pr_warn("Freeing item from a non-empty queue\n");
+ kfree(entry);
+ }
+
+ while ((entry =
+ ntb_list_rm_head(&qp->ntb_rx_comp_q_lock, &qp->rx_comp_q))) {
+ pr_warn("Freeing item from a non-empty queue\n");
+ kfree(entry);
+ }
+
+ while ((entry =
+ ntb_list_rm_head(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
+ kfree(entry);
+
+ while ((entry =
+ ntb_list_rm_head(&qp->ntb_tx_pend_q_lock, &qp->tx_pend_q))) {
+ pr_warn("Freeing item from a non-empty queue\n");
+ kfree(entry);
+ }
+
+ while ((entry =
+ ntb_list_rm_head(&qp->ntb_tx_comp_q_lock, &qp->tx_comp_q))) {
+ pr_warn("Freeing item from a non-empty queue\n");
+ kfree(entry);
+ }
+
+ set_bit(qp->qp_num, &qp->transport->qp_bitmap);
+
+ pr_info("NTB Transport QP %d freed\n", qp->qp_num);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
+
+/**
+ * ntb_transport_rx_remove - Dequeues enqueued rx packet
+ * @qp: NTB queue to be freed
+ * @len: pointer to variable to write enqueued buffers length
+ *
+ * Dequeues unused buffers from receive queue. Should only be used during
+ * shutdown of qp.
+ *
+ * RETURNS: NULL error value on error, or void* for success.
+ */
+void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
+{
+ struct ntb_queue_entry *entry;
+ void *buf;
+
+ if (!qp || qp->client_ready == NTB_LINK_UP)
+ return NULL;
+
+ entry = ntb_list_rm_head(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
+ if (!entry)
+ return NULL;
+
+ buf = entry->callback_data;
+ *len = entry->len;
+
+ ntb_list_add_tail(&qp->ntb_rx_free_q_lock, &entry->entry,
+ &qp->rx_free_q);
+
+ return buf;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
+
+/**
+ * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
+ * @qp: NTB transport layer queue the entry is to be enqueued on
+ * @cb: per buffer pointer for callback function to use
+ * @data: pointer to data buffer that incoming packets will be copied into
+ * @len: length of the data buffer
+ *
+ * Enqueue a new receive buffer onto the transport queue into which a NTB
+ * payload can be received into.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
+ unsigned int len)
+{
+ struct ntb_queue_entry *entry;
+
+ if (!qp)
+ return -EINVAL;
+
+ entry = ntb_list_rm_head(&qp->ntb_rx_free_q_lock, &qp->rx_free_q);
+ if (!entry)
+ return -ENOMEM;
+
+ entry->callback_data = cb;
+ entry->buf = data;
+ entry->len = len;
+
+ ntb_list_add_tail(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
+
+/**
+ * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
+ * @qp: NTB transport layer queue the entry is to be enqueued on
+ * @cb: per buffer pointer for callback function to use
+ * @data: pointer to data buffer that will be sent
+ * @len: length of the data buffer
+ *
+ * Enqueue a new transmit buffer onto the transport queue from which a NTB
+ * payload will be transmitted.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
+ unsigned int len)
+{
+ struct ntb_queue_entry *entry;
+
+ if (!qp || qp->qp_link != NTB_LINK_UP || !len)
+ return -EINVAL;
+
+ entry = ntb_list_rm_head(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
+ if (!entry) {
+ /* ring full, kick it */
+ tasklet_schedule(&qp->tx_work);
+ return -ENOMEM;
+ }
+
+ entry->callback_data = cb;
+ entry->buf = data;
+ entry->len = len;
+ entry->flags = 0;
+
+ ntb_list_add_tail(&qp->ntb_tx_pend_q_lock, &entry->entry,
+ &qp->tx_pend_q);
+
+ tasklet_schedule(&qp->tx_work);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
+
+/**
+ * ntb_transport_tx_dequeue - Dequeue a NTB queue entry
+ * @qp: NTB transport layer queue to be dequeued from
+ * @len: length of the data buffer
+ *
+ * This function will dequeue a buffer from the transmit complete queue.
+ * Entries will only be enqueued on this queue after having been
+ * transfered to the remote side.
+ *
+ * RETURNS: callback pointer of the buffer from the transport queue, or NULL
+ * on empty
+ */
+void *ntb_transport_tx_dequeue(struct ntb_transport_qp *qp, unsigned int *len)
+{
+ struct ntb_queue_entry *entry;
+ void *buf;
+
+ if (!qp)
+ return NULL;
+
+ entry = ntb_list_rm_head(&qp->ntb_tx_comp_q_lock, &qp->tx_comp_q);
+ if (!entry)
+ return NULL;
+
+ buf = entry->callback_data;
+ if (entry->flags != HW_ERROR_FLAG)
+ *len = entry->len;
+ else
+ *len = -EIO;
+
+ ntb_list_add_tail(&qp->ntb_tx_free_q_lock, &entry->entry,
+ &qp->tx_free_q);
+
+ return buf;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_tx_dequeue);
+
+/**
+ * ntb_transport_rx_dequeue - Dequeue a NTB queue entry
+ * @qp: NTB transport layer queue to be dequeued from
+ * @len: length of the data buffer
+ *
+ * This function will dequeue a buffer from the receive complete queue.
+ * Entries will only be enqueued on this queue after having been fully received.
+ *
+ * RETURNS: callback pointer of the buffer from the transport queue, or NULL
+ * on empty
+ */
+void *ntb_transport_rx_dequeue(struct ntb_transport_qp *qp, unsigned int *len)
+{
+ struct ntb_queue_entry *entry;
+ void *buf;
+
+ if (!qp)
+ return NULL;
+
+ entry = ntb_list_rm_head(&qp->ntb_rx_comp_q_lock, &qp->rx_comp_q);
+ if (!entry)
+ return NULL;
+
+ buf = entry->callback_data;
+ *len = entry->len;
+
+ ntb_list_add_tail(&qp->ntb_rx_free_q_lock, &entry->entry,
+ &qp->rx_free_q);
+
+ return buf;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_rx_dequeue);
+
+/**
+ * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
+ * @qp: NTB transport layer queue to be enabled
+ *
+ * Notify NTB transport layer of client readiness to use queue
+ */
+void ntb_transport_link_up(struct ntb_transport_qp *qp)
+{
+ if (!qp)
+ return;
+
+ qp->client_ready = NTB_LINK_UP;
+
+ if (qp->transport->transport_link == NTB_LINK_UP)
+ schedule_delayed_work(&qp->link_work, 0);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_link_up);
+
+/**
+ * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
+ * @qp: NTB transport layer queue to be disabled
+ *
+ * Notify NTB transport layer of client's desire to no longer receive data on
+ * transport queue specified. It is the client's responsibility to ensure all
+ * entries on queue are purged or otherwise handled appropraitely.
+ */
+void ntb_transport_link_down(struct ntb_transport_qp *qp)
+{
+ int rc, val;
+
+ if (!qp)
+ return;
+
+ qp->client_ready = NTB_LINK_DOWN;
+
+ cancel_delayed_work_sync(&qp->link_work);
+ qp->qp_link = NTB_LINK_DOWN;
+
+ rc = ntb_read_local_spad(qp->ndev, QP_LINKS, &val);
+ if (rc) {
+ pr_err("Error reading spad %d\n", QP_LINKS);
+ return;
+ }
+
+ rc = ntb_write_remote_spad(qp->ndev, QP_LINKS,
+ val & ~(1 << qp->qp_num));
+ if (rc)
+ pr_err("Error writing %x to remote spad %d\n",
+ val & ~(1 << qp->qp_num), QP_LINKS);
+
+ if (qp->transport->transport_link == NTB_LINK_UP)
+ ntb_send_link_down(qp);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_link_down);
+
+/**
+ * ntb_transport_link_query - Query transport link state
+ * @qp: NTB transport layer queue to be queried
+ *
+ * Query connectivity to the remote system of the NTB transport queue
+ *
+ * RETURNS: true for link up or false for link down
+ */
+bool ntb_transport_link_query(struct ntb_transport_qp *qp)
+{
+ return qp->qp_link == NTB_LINK_UP;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_link_query);
+
+/**
+ * ntb_transport_qp_num - Query the qp number
+ * @qp: NTB transport layer queue to be queried
+ *
+ * Query qp number of the NTB transport queue
+ *
+ * RETURNS: a zero based number specifying the qp number
+ */
+unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
+{
+ return qp->qp_num;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
+
+/**
+ * ntb_transport_max_size - Query the max payload size of a qp
+ * @qp: NTB transport layer queue to be queried
+ *
+ * Query the maximum payload size permissible on the given qp
+ *
+ * RETURNS: the max payload size of a qp
+ */
+unsigned int
+ntb_transport_max_size(__attribute__((unused)) struct ntb_transport_qp *qp)
+{
+ return transport_mtu;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_max_size);
+
+
+
+static int ntb_client_probe(const struct ntb_client *drvr)
+{
+ struct ntb_transport *nt;
+ int rc = -EINVAL;
+
+ list_for_each_entry(nt, &ntb_transport_list, list) {
+ rc = drvr->probe(ntb_query_pdev(nt->ndev));
+ if (rc)
+ break;
+ }
+
+ return rc;
+}
+
+/**
+ * register_ntb_client - Register NTB client driver
+ * @drvr: NTB client driver to be registered
+ *
+ * Register an NTB client driver with the NTB transport layer
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int register_ntb_client(const struct ntb_client *drvr)
+{
+ if (!list_empty(&ntb_transport_list))
+ return ntb_client_probe(drvr);
+ else
+ return 0;
+}
+EXPORT_SYMBOL_GPL(register_ntb_client);
+
+static void ntb_client_remove(const struct ntb_client *drvr)
+{
+ struct ntb_transport *nt;
+
+ list_for_each_entry(nt, &ntb_transport_list, list)
+ drvr->remove(ntb_query_pdev(nt->ndev));
+}
+
+/**
+ * unregister_ntb_client - Unregister NTB client driver
+ * @drvr: NTB client driver to be unregistered
+ *
+ * Unregister an NTB client driver with the NTB transport layer
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+void unregister_ntb_client(const struct ntb_client *drvr)
+{
+ if (!list_empty(&ntb_transport_list))
+ ntb_client_remove(drvr);
+}
+EXPORT_SYMBOL_GPL(unregister_ntb_client);
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
new file mode 100644
index 0000000..027bb0b
--- /dev/null
+++ b/include/linux/ntb.h
@@ -0,0 +1,92 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license. When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ * The full GNU General Public License is included in this distribution
+ * in the file called LICENSE.GPL.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copy
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Intel PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Jon Mason <jon.mason [at] intel>
+ */
+
+struct ntb_transport_qp;
+
+struct ntb_client {
+ char *name;
+ int (*probe) (struct pci_dev *pdev);
+ void (*remove) (struct pci_dev *pdev);
+};
+
+int register_ntb_client(const struct ntb_client *drvr);
+void unregister_ntb_client(const struct ntb_client *drvr);
+
+struct ntb_queue_handlers {
+ void (*tx_handler) (void *data, struct ntb_transport_qp *qp);
+ void (*rx_handler) (void *data, struct ntb_transport_qp *qp);
+ void (*event_handler) (void *data, int status);
+};
+
+unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp);
+unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp);
+struct ntb_transport_qp *
+ntb_transport_create_queue(void *data, struct pci_dev *pdev,
+ const struct ntb_queue_handlers *handlers);
+void ntb_transport_free_queue(struct ntb_transport_qp *qp);
+int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
+ unsigned int len);
+int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
+ unsigned int len);
+void *ntb_transport_tx_dequeue(struct ntb_transport_qp *qp, unsigned int *len);
+void *ntb_transport_rx_dequeue(struct ntb_transport_qp *qp, unsigned int *len);
+void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len);
+void ntb_transport_link_up(struct ntb_transport_qp *qp);
+void ntb_transport_link_down(struct ntb_transport_qp *qp);
+bool ntb_transport_link_query(struct ntb_transport_qp *qp);
--
1.7.5.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


bhelgaas at google

Jul 30, 2012, 9:50 AM

Post #2 of 20 (219 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Sun, Jul 29, 2012 at 6:26 PM, Jon Mason <jon.mason [at] intel> wrote:
> A PCI-Express non-transparent bridge (NTB) is a point-to-point PCIe bus
> connecting 2 systems, providing electrical isolation between the two subsystems.
> A non-transparent bridge is functionally similar to a transparent bridge except
> that both sides of the bridge have their own independent address domains. The
> host on one side of the bridge will not have the visibility of the complete
> memory or I/O space on the other side of the bridge. To communicate across the
> non-transparent bridge, each NTB endpoint has one (or more) apertures exposed to
> the local system. Writes to these apertures are mirrored to memory on the
> remote system. Communications can also occur through the use of doorbell
> registers that initiate interrupts to the alternate domain, and scratch-pad
> registers accessible from both sides.
>
> The NTB device driver is needed to configure these memory windows, doorbell, and
> scratch-pad registers as well as use them in such a way as they can be turned
> into a viable communication channel to the remote system. ntb_hw.[ch]
> determines the usage model (NTB to NTB or NTB to Root Port) and abstracts away
> the underlying hardware to provide access and a common interface to the doorbell
> registers, scratch pads, and memory windows. These hardware interfaces are
> exported so that other, non-mainlined kernel drivers can access these.
> ntb_transport.[ch] also uses the exported interfaces in ntb_hw.[ch] to setup a
> communication channel(s) and provide a reliable way of transferring data from
> one side to the other, which it then exports so that "client" drivers can access
> them. These client drivers are used to provide a standard kernel interface
> (i.e., Ethernet device) to NTB, such that Linux can transfer data from one
> system to the other in a standard way.
>
> Signed-off-by: Jon Mason <jon.mason [at] intel>
> ---
> MAINTAINERS | 6 +
> drivers/Kconfig | 2 +
> drivers/Makefile | 1 +
> drivers/ntb/Kconfig | 13 +
> drivers/ntb/Makefile | 3 +
> drivers/ntb/ntb_hw.c | 1178 ++++++++++++++++++++++++++++++++++++
> drivers/ntb/ntb_hw.h | 206 +++++++
> drivers/ntb/ntb_regs.h | 150 +++++
> drivers/ntb/ntb_transport.c | 1387 +++++++++++++++++++++++++++++++++++++++++++
> include/linux/ntb.h | 92 +++

Where will drivers for non-Intel NTBs fit in this hierarchy? It seems
a bit presumptuous to claim the generic "ntb" names just for Intel
devices.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


jon.mason at intel

Jul 30, 2012, 11:15 AM

Post #3 of 20 (221 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Mon, Jul 30, 2012 at 10:50:13AM -0600, Bjorn Helgaas wrote:
> On Sun, Jul 29, 2012 at 6:26 PM, Jon Mason <jon.mason [at] intel> wrote:
> > A PCI-Express non-transparent bridge (NTB) is a point-to-point PCIe bus
> > connecting 2 systems, providing electrical isolation between the two subsystems.
> > A non-transparent bridge is functionally similar to a transparent bridge except
> > that both sides of the bridge have their own independent address domains. The
> > host on one side of the bridge will not have the visibility of the complete
> > memory or I/O space on the other side of the bridge. To communicate across the
> > non-transparent bridge, each NTB endpoint has one (or more) apertures exposed to
> > the local system. Writes to these apertures are mirrored to memory on the
> > remote system. Communications can also occur through the use of doorbell
> > registers that initiate interrupts to the alternate domain, and scratch-pad
> > registers accessible from both sides.
> >
> > The NTB device driver is needed to configure these memory windows, doorbell, and
> > scratch-pad registers as well as use them in such a way as they can be turned
> > into a viable communication channel to the remote system. ntb_hw.[ch]
> > determines the usage model (NTB to NTB or NTB to Root Port) and abstracts away
> > the underlying hardware to provide access and a common interface to the doorbell
> > registers, scratch pads, and memory windows. These hardware interfaces are
> > exported so that other, non-mainlined kernel drivers can access these.
> > ntb_transport.[ch] also uses the exported interfaces in ntb_hw.[ch] to setup a
> > communication channel(s) and provide a reliable way of transferring data from
> > one side to the other, which it then exports so that "client" drivers can access
> > them. These client drivers are used to provide a standard kernel interface
> > (i.e., Ethernet device) to NTB, such that Linux can transfer data from one
> > system to the other in a standard way.
> >
> > Signed-off-by: Jon Mason <jon.mason [at] intel>
> > ---
> > MAINTAINERS | 6 +
> > drivers/Kconfig | 2 +
> > drivers/Makefile | 1 +
> > drivers/ntb/Kconfig | 13 +
> > drivers/ntb/Makefile | 3 +
> > drivers/ntb/ntb_hw.c | 1178 ++++++++++++++++++++++++++++++++++++
> > drivers/ntb/ntb_hw.h | 206 +++++++
> > drivers/ntb/ntb_regs.h | 150 +++++
> > drivers/ntb/ntb_transport.c | 1387 +++++++++++++++++++++++++++++++++++++++++++
> > include/linux/ntb.h | 92 +++
>
> Where will drivers for non-Intel NTBs fit in this hierarchy? It seems
> a bit presumptuous to claim the generic "ntb" names just for Intel
> devices.

I've tried to make it all generic enough that non-Intel NTBs should plug in with
minimal changes to ntb_hw.c. If their design is too divergent, then a slight
redesign of ntb_hw.c might be necessary. But from what I've seen of other
designs on the internet, they appear to be extremely similar. The transport and
client drivers were written with the hardware abstracted away as much as
possible to prevent the need to modify it for different hardware. If there is
anything which is Intel hardware specific, I'd be happy to change it to make it
more generic.

Thanks,
Jon
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


kjbmail at gmail

Jul 30, 2012, 8:35 PM

Post #4 of 20 (224 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

> I've tried to make it all generic enough that non-Intel NTBs should plug in with
> minimal changes to ntb_hw.c. If their design is too divergent, then a slight
> redesign of ntb_hw.c might be necessary. But from what I've seen of other
> designs on the internet, they appear to be extremely similar. The transport and
> client drivers were written with the hardware abstracted away as much as
> possible to prevent the need to modify it for different hardware. If there is
> anything which is Intel hardware specific, I'd be happy to change it to make it
> more generic.
In ntb_process_tx(), ntb uses hard-coding 'memcpy_toio' to copy data
to remote.
Is it better to provide a function pointer like 'tx()' and call qp->tx().
memcpy_toio is a slow operation. Some hardware can setup a dma
transfer and wait.

IMHO, the best way is to handle tx in async mode. But it requires
lots of modification.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


bhelgaas at google

Jul 31, 2012, 6:45 AM

Post #5 of 20 (215 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Mon, Jul 30, 2012 at 12:15 PM, Jon Mason <jon.mason [at] intel> wrote:
> On Mon, Jul 30, 2012 at 10:50:13AM -0600, Bjorn Helgaas wrote:
>> On Sun, Jul 29, 2012 at 6:26 PM, Jon Mason <jon.mason [at] intel> wrote:
>> > A PCI-Express non-transparent bridge (NTB) is a point-to-point PCIe bus
>> > connecting 2 systems, providing electrical isolation between the two subsystems.
>> > A non-transparent bridge is functionally similar to a transparent bridge except
>> > that both sides of the bridge have their own independent address domains. The
>> > host on one side of the bridge will not have the visibility of the complete
>> > memory or I/O space on the other side of the bridge. To communicate across the
>> > non-transparent bridge, each NTB endpoint has one (or more) apertures exposed to
>> > the local system. Writes to these apertures are mirrored to memory on the
>> > remote system. Communications can also occur through the use of doorbell
>> > registers that initiate interrupts to the alternate domain, and scratch-pad
>> > registers accessible from both sides.
>> >
>> > The NTB device driver is needed to configure these memory windows, doorbell, and
>> > scratch-pad registers as well as use them in such a way as they can be turned
>> > into a viable communication channel to the remote system. ntb_hw.[ch]
>> > determines the usage model (NTB to NTB or NTB to Root Port) and abstracts away
>> > the underlying hardware to provide access and a common interface to the doorbell
>> > registers, scratch pads, and memory windows. These hardware interfaces are
>> > exported so that other, non-mainlined kernel drivers can access these.
>> > ntb_transport.[ch] also uses the exported interfaces in ntb_hw.[ch] to setup a
>> > communication channel(s) and provide a reliable way of transferring data from
>> > one side to the other, which it then exports so that "client" drivers can access
>> > them. These client drivers are used to provide a standard kernel interface
>> > (i.e., Ethernet device) to NTB, such that Linux can transfer data from one
>> > system to the other in a standard way.
>> >
>> > Signed-off-by: Jon Mason <jon.mason [at] intel>
>> > ---
>> > MAINTAINERS | 6 +
>> > drivers/Kconfig | 2 +
>> > drivers/Makefile | 1 +
>> > drivers/ntb/Kconfig | 13 +
>> > drivers/ntb/Makefile | 3 +
>> > drivers/ntb/ntb_hw.c | 1178 ++++++++++++++++++++++++++++++++++++
>> > drivers/ntb/ntb_hw.h | 206 +++++++
>> > drivers/ntb/ntb_regs.h | 150 +++++
>> > drivers/ntb/ntb_transport.c | 1387 +++++++++++++++++++++++++++++++++++++++++++
>> > include/linux/ntb.h | 92 +++
>>
>> Where will drivers for non-Intel NTBs fit in this hierarchy? It seems
>> a bit presumptuous to claim the generic "ntb" names just for Intel
>> devices.
>
> I've tried to make it all generic enough that non-Intel NTBs should plug in with
> minimal changes to ntb_hw.c. If their design is too divergent, then a slight
> redesign of ntb_hw.c might be necessary. But from what I've seen of other
> designs on the internet, they appear to be extremely similar. The transport and
> client drivers were written with the hardware abstracted away as much as
> possible to prevent the need to modify it for different hardware. If there is
> anything which is Intel hardware specific, I'd be happy to change it to make it
> more generic.

That makes sense from a technical point of view, but I think it's
going to cause maintenance issues. For example, assume PLX NTB
support is added. Will PLX be happy about having to convince you to
accept changes? Will Intel be happy about having to release a new
driver for their hardware just to incorporate a PLX bug fix? Will
users of PLX hardware accept a new driver release that only benefits
Intel users?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


loke.chetan at gmail

Jul 31, 2012, 9:02 AM

Post #6 of 20 (216 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 9:45 AM, Bjorn Helgaas <bhelgaas [at] google> wrote:
> On Mon, Jul 30, 2012 at 12:15 PM, Jon Mason <jon.mason [at] intel> wrote:
>>
>> I've tried to make it all generic enough that non-Intel NTBs should plug in with
>> minimal changes to ntb_hw.c. If their design is too divergent, then a slight
>> redesign of ntb_hw.c might be necessary. But from what I've seen of other
>> designs on the internet, they appear to be extremely similar. The transport and
>> client drivers were written with the hardware abstracted away as much as
>> possible to prevent the need to modify it for different hardware. If there is
>> anything which is Intel hardware specific, I'd be happy to change it to make it
>> more generic.
>
> That makes sense from a technical point of view, but I think it's
> going to cause maintenance issues. For example, assume PLX NTB
> support is added. Will PLX be happy about having to convince you to
> accept changes? Will Intel be happy about having to release a new

Do you mean convince Intel? Well, if we think of ntb as the class
driver then the onus is on the community to vet the changes and NOT
intel.
And since this is the first NTB part for which the support is
introduced the class driver design could be a moving target. As
someone else mentioned, the async/sync tx-dma is another hook that
could change the class driver's design.


> driver for their hardware just to incorporate a PLX bug fix? Will
> users of PLX hardware accept a new driver release that only benefits
> Intel users?

May be till the class driver is stable, the client(intel/PLX) drivers
might have to be modified. This is a cue for other vendors to
chime-in and review this design?
Just thinking if this could sit in staging for some time(so that
others get a chance to review/suggest changes as well) and then get
promoted out of staging.

Chetan Loke
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


loke.chetan at gmail

Jul 31, 2012, 9:14 AM

Post #7 of 20 (220 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Sun, Jul 29, 2012 at 8:26 PM, Jon Mason <jon.mason [at] intel> wrote:

<snip>

> +static void ntb_tx_copy_task(struct ntb_transport_qp *qp,
> + struct ntb_queue_entry *entry,
> + void *offset)
> +{
> + struct ntb_payload_header *hdr = offset;
> +
> + offset += sizeof(struct ntb_payload_header);
> + memcpy_toio(offset, entry->buf, entry->len);
> +
> + hdr->len = entry->len;
> + hdr->ver = qp->tx_pkts;
> +
> + /* Ensure that the data is fully copied out before setting the flag */
> + wmb();
> + hdr->flags = entry->flags | DESC_DONE_FLAG;
> +
> + ntb_ring_sdb(qp->ndev, qp->qp_num);
> +
> + /* The entry length can only be zero if the packet is intended to be a
> + * "link down" or similar. Since no payload is being sent in these
> + * cases, there is nothing to add to the completion queue.
> + */
> + if (entry->len > 0) {
> + qp->tx_bytes += entry->len;
> +
> + /* Add fully transmitted data to completion queue */
> + ntb_list_add_tail(&qp->ntb_tx_comp_q_lock, &entry->entry,
> + &qp->tx_comp_q);
> +
> + if (qp->tx_handler)
> + qp->tx_handler(qp->cb_data, qp);
> + } else
> + ntb_list_add_tail(&qp->ntb_tx_free_q_lock, &entry->entry,
> + &qp->tx_free_q);
> +}

I know you talked about a fixed array. But it's not here yet. So at
all the call-sites, for [r/t]x_free_q , add the 'entry' to the head -
change to ntb_list_add_head here and else where.

Chetan Loke
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


jon.mason at intel

Jul 31, 2012, 9:33 AM

Post #8 of 20 (219 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 11:35:33AM +0800, Jianbin Kang wrote:
> > I've tried to make it all generic enough that non-Intel NTBs should plug in with
> > minimal changes to ntb_hw.c. If their design is too divergent, then a slight
> > redesign of ntb_hw.c might be necessary. But from what I've seen of other
> > designs on the internet, they appear to be extremely similar. The transport and
> > client drivers were written with the hardware abstracted away as much as
> > possible to prevent the need to modify it for different hardware. If there is
> > anything which is Intel hardware specific, I'd be happy to change it to make it
> > more generic.
> In ntb_process_tx(), ntb uses hard-coding 'memcpy_toio' to copy data
> to remote.
> Is it better to provide a function pointer like 'tx()' and call qp->tx().
> memcpy_toio is a slow operation. Some hardware can setup a dma
> transfer and wait.
>
> IMHO, the best way is to handle tx in async mode. But it requires
> lots of modification.

Actually this is what I'm working on now, using async_tx to replace the
memcpy. I believe the changes shouldn't be that significant.

Is the "hardware that can setup dma" you refer to something that does
not use this interface?

Thanks,
Jon
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


bhelgaas at google

Jul 31, 2012, 10:03 AM

Post #9 of 20 (213 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 10:02 AM, chetan loke <loke.chetan [at] gmail> wrote:
> On Tue, Jul 31, 2012 at 9:45 AM, Bjorn Helgaas <bhelgaas [at] google> wrote:
>> On Mon, Jul 30, 2012 at 12:15 PM, Jon Mason <jon.mason [at] intel> wrote:
>>>
>>> I've tried to make it all generic enough that non-Intel NTBs should plug in with
>>> minimal changes to ntb_hw.c. If their design is too divergent, then a slight
>>> redesign of ntb_hw.c might be necessary. But from what I've seen of other
>>> designs on the internet, they appear to be extremely similar. The transport and
>>> client drivers were written with the hardware abstracted away as much as
>>> possible to prevent the need to modify it for different hardware. If there is
>>> anything which is Intel hardware specific, I'd be happy to change it to make it
>>> more generic.
>>
>> That makes sense from a technical point of view, but I think it's
>> going to cause maintenance issues. For example, assume PLX NTB
>> support is added. Will PLX be happy about having to convince you to
>> accept changes? Will Intel be happy about having to release a new
>
> Do you mean convince Intel? Well, if we think of ntb as the class
> driver then the onus is on the community to vet the changes and NOT
> intel.

No, I said convince "you," meaning *Jon*. Intel doesn't apply
patches. "The community" doesn't apply patches. Jon applies patches.
This has nothing to do with the fact that Jon is employed by Intel.
The point is that when you have multiple organizations involved, they
have different goals, markets, customers, and schedules. If one
module contains both Intel-specific and PLX-specific things, that's a
place where these organizational differences may cause issues,
regardless of who is applying the patches.

Obviously it's not a problem now, and maybe it will never be. But I
think there's a possibility. Since I have no direct interest in any
of these devices, I'm only raising that possibility, not trying to
force any particular direction.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


jon.mason at intel

Jul 31, 2012, 10:10 AM

Post #10 of 20 (235 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 07:45:29AM -0600, Bjorn Helgaas wrote:
> On Mon, Jul 30, 2012 at 12:15 PM, Jon Mason <jon.mason [at] intel> wrote:
> > On Mon, Jul 30, 2012 at 10:50:13AM -0600, Bjorn Helgaas wrote:
> >> On Sun, Jul 29, 2012 at 6:26 PM, Jon Mason <jon.mason [at] intel> wrote:
> >> > A PCI-Express non-transparent bridge (NTB) is a point-to-point PCIe bus
> >> > connecting 2 systems, providing electrical isolation between the two subsystems.
> >> > A non-transparent bridge is functionally similar to a transparent bridge except
> >> > that both sides of the bridge have their own independent address domains. The
> >> > host on one side of the bridge will not have the visibility of the complete
> >> > memory or I/O space on the other side of the bridge. To communicate across the
> >> > non-transparent bridge, each NTB endpoint has one (or more) apertures exposed to
> >> > the local system. Writes to these apertures are mirrored to memory on the
> >> > remote system. Communications can also occur through the use of doorbell
> >> > registers that initiate interrupts to the alternate domain, and scratch-pad
> >> > registers accessible from both sides.
> >> >
> >> > The NTB device driver is needed to configure these memory windows, doorbell, and
> >> > scratch-pad registers as well as use them in such a way as they can be turned
> >> > into a viable communication channel to the remote system. ntb_hw.[ch]
> >> > determines the usage model (NTB to NTB or NTB to Root Port) and abstracts away
> >> > the underlying hardware to provide access and a common interface to the doorbell
> >> > registers, scratch pads, and memory windows. These hardware interfaces are
> >> > exported so that other, non-mainlined kernel drivers can access these.
> >> > ntb_transport.[ch] also uses the exported interfaces in ntb_hw.[ch] to setup a
> >> > communication channel(s) and provide a reliable way of transferring data from
> >> > one side to the other, which it then exports so that "client" drivers can access
> >> > them. These client drivers are used to provide a standard kernel interface
> >> > (i.e., Ethernet device) to NTB, such that Linux can transfer data from one
> >> > system to the other in a standard way.
> >> >
> >> > Signed-off-by: Jon Mason <jon.mason [at] intel>
> >> > ---
> >> > MAINTAINERS | 6 +
> >> > drivers/Kconfig | 2 +
> >> > drivers/Makefile | 1 +
> >> > drivers/ntb/Kconfig | 13 +
> >> > drivers/ntb/Makefile | 3 +
> >> > drivers/ntb/ntb_hw.c | 1178 ++++++++++++++++++++++++++++++++++++
> >> > drivers/ntb/ntb_hw.h | 206 +++++++
> >> > drivers/ntb/ntb_regs.h | 150 +++++
> >> > drivers/ntb/ntb_transport.c | 1387 +++++++++++++++++++++++++++++++++++++++++++
> >> > include/linux/ntb.h | 92 +++
> >>
> >> Where will drivers for non-Intel NTBs fit in this hierarchy? It seems
> >> a bit presumptuous to claim the generic "ntb" names just for Intel
> >> devices.
> >
> > I've tried to make it all generic enough that non-Intel NTBs should plug in with
> > minimal changes to ntb_hw.c. If their design is too divergent, then a slight
> > redesign of ntb_hw.c might be necessary. But from what I've seen of other
> > designs on the internet, they appear to be extremely similar. The transport and
> > client drivers were written with the hardware abstracted away as much as
> > possible to prevent the need to modify it for different hardware. If there is
> > anything which is Intel hardware specific, I'd be happy to change it to make it
> > more generic.
>
> That makes sense from a technical point of view, but I think it's
> going to cause maintenance issues. For example, assume PLX NTB
> support is added. Will PLX be happy about having to convince you to
> accept changes? Will Intel be happy about having to release a new
> driver for their hardware just to incorporate a PLX bug fix? Will
> users of PLX hardware accept a new driver release that only benefits
> Intel users?

Firstly, I don't believe this is an issue. The amount of hardware
specific code is small (<150 loc), and the design of the PLX hardware
appears to be the same as Intel (from what I've read on the internet).

Assuming Intel is me, I am always happy to do whatever I can to help
PLX or any other NTB vendor. I am willing to make internal releases
(which I am assuming is the issue you are referring to) for any change
to the driver.

If necessary, refactoring the driver shouldn't be a significant issue.
However, I would prefer to do it if/when another NTB driver wants to
be added. PLX (and those who are using their NTB hardware) hasn't
pushed an NTB driver yet, and may never (as their design docs on the
web are from '05). Why complicate the driver for them if they never
come?

Thanks,
Jon

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


jon.mason at intel

Jul 31, 2012, 10:27 AM

Post #11 of 20 (213 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 12:02:20PM -0400, chetan loke wrote:
> On Tue, Jul 31, 2012 at 9:45 AM, Bjorn Helgaas <bhelgaas [at] google> wrote:
> > On Mon, Jul 30, 2012 at 12:15 PM, Jon Mason <jon.mason [at] intel> wrote:
> >>
> >> I've tried to make it all generic enough that non-Intel NTBs should plug in with
> >> minimal changes to ntb_hw.c. If their design is too divergent, then a slight
> >> redesign of ntb_hw.c might be necessary. But from what I've seen of other
> >> designs on the internet, they appear to be extremely similar. The transport and
> >> client drivers were written with the hardware abstracted away as much as
> >> possible to prevent the need to modify it for different hardware. If there is
> >> anything which is Intel hardware specific, I'd be happy to change it to make it
> >> more generic.
> >
> > That makes sense from a technical point of view, but I think it's
> > going to cause maintenance issues. For example, assume PLX NTB
> > support is added. Will PLX be happy about having to convince you to
> > accept changes? Will Intel be happy about having to release a new
>
> Do you mean convince Intel? Well, if we think of ntb as the class
> driver then the onus is on the community to vet the changes and NOT
> intel.
> And since this is the first NTB part for which the support is
> introduced the class driver design could be a moving target. As
> someone else mentioned, the async/sync tx-dma is another hook that
> could change the class driver's design.
>
>
> > driver for their hardware just to incorporate a PLX bug fix? Will
> > users of PLX hardware accept a new driver release that only benefits
> > Intel users?
>
> May be till the class driver is stable, the client(intel/PLX) drivers
> might have to be modified. This is a cue for other vendors to
> chime-in and review this design?
> Just thinking if this could sit in staging for some time(so that
> others get a chance to review/suggest changes as well) and then get
> promoted out of staging.

I don't see the benefit of having the driver in staging. Any vendors
who would notice the ntb driver in staging would be sitting on these
mailing lists and hopefully have planety of comments on the design.
Stashing the driver in staging while waiting for these comments (which
may never come) doesn't seem the best course of action.

Thanks,
Jon

>
> Chetan Loke
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


loke.chetan at gmail

Jul 31, 2012, 11:02 AM

Post #12 of 20 (206 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 1:27 PM, Jon Mason <jon.mason [at] intel> wrote:
>
> I don't see the benefit of having the driver in staging. Any vendors
> who would notice the ntb driver in staging would be sitting on these
> mailing lists and hopefully have planety of comments on the design.
> Stashing the driver in staging while waiting for these comments (which
> may never come) doesn't seem the best course of action.
>

I thought that since others are talking about it then may be there is
some WIP code for foo-NTB. Seems like that's not the case. So no need
to stage.

Correct me if I'm wrong but wouldn't apps just open a socket and route
data via ntb_vir_eth_dev? So I don't see an ABI breakage issue and
hence nothing would prevent us from changing the kernel parts(for
accommodating some foo-NTB part) in future.

It may not be a bad idea to prefix intel-specific(if any)
ntb_structs/variables/logic with the 'intc'(Intel ticker or pick your
string) keyword.

Chetan Loke
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


gregkh at linuxfoundation

Jul 31, 2012, 3:23 PM

Post #13 of 20 (214 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Sun, Jul 29, 2012 at 05:26:33PM -0700, Jon Mason wrote:
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

You really are going to track the FSF's office movements for the next
40+ years?

> + * The full GNU General Public License is included in this distribution
> + * in the file called LICENSE.GPL.

No it isn't, this sentance is totally wrong for any in-kernel code,
please remove it.

Also do the same for all the other files you added please.

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


gregkh at linuxfoundation

Jul 31, 2012, 3:25 PM

Post #14 of 20 (210 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Sun, Jul 29, 2012 at 05:26:33PM -0700, Jon Mason wrote:
> +struct ntb_transport_qp;
> +
> +struct ntb_client {
> + char *name;
> + int (*probe) (struct pci_dev *pdev);
> + void (*remove) (struct pci_dev *pdev);
> +};

Why isn't this tied into the driver model? That looks like you really
want to use a 'struct device' here, right?

Then you have drivers that bind to them, and your devices show up in
sysfs, which is probably a requirement you have, right?

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


jon.mason at intel

Jul 31, 2012, 3:51 PM

Post #15 of 20 (214 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 03:23:38PM -0700, Greg KH wrote:
> On Sun, Jul 29, 2012 at 05:26:33PM -0700, Jon Mason wrote:
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
>
> You really are going to track the FSF's office movements for the next
> 40+ years?
>
> > + * The full GNU General Public License is included in this distribution
> > + * in the file called LICENSE.GPL.
>
> No it isn't, this sentance is totally wrong for any in-kernel code,
> please remove it.
>
> Also do the same for all the other files you added please.

I echo'ed your original comments on this to Intel Legal and am waiting
on a response. I 100% agree, but I need their signoff first.

It is worth noting that this version of the license is already in the
kernel in numerous other drivers:
drivers/sfi/*
drivers/scsi/isci/*
drivers/dma/ioat/dma_v3.c
drivers/net/wireless/iwlwifi/*
drivers/net/wireless/iwlegacy/*

Thanks,
Jon

>
> greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


gregkh at linuxfoundation

Jul 31, 2012, 4:14 PM

Post #16 of 20 (206 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 03:51:05PM -0700, Jon Mason wrote:
> On Tue, Jul 31, 2012 at 03:23:38PM -0700, Greg KH wrote:
> > On Sun, Jul 29, 2012 at 05:26:33PM -0700, Jon Mason wrote:
> > > + * You should have received a copy of the GNU General Public License
> > > + * along with this program; if not, write to the Free Software
> > > + * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
> >
> > You really are going to track the FSF's office movements for the next
> > 40+ years?
> >
> > > + * The full GNU General Public License is included in this distribution
> > > + * in the file called LICENSE.GPL.
> >
> > No it isn't, this sentance is totally wrong for any in-kernel code,
> > please remove it.
> >
> > Also do the same for all the other files you added please.
>
> I echo'ed your original comments on this to Intel Legal and am waiting
> on a response. I 100% agree, but I need their signoff first.
>
> It is worth noting that this version of the license is already in the
> kernel in numerous other drivers:
> drivers/sfi/*
> drivers/scsi/isci/*
> drivers/dma/ioat/dma_v3.c
> drivers/net/wireless/iwlwifi/*
> drivers/net/wireless/iwlegacy/*

Just because others got it wrong, doesn't mean you need to continue to :)

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


kjbmail at gmail

Jul 31, 2012, 7:10 PM

Post #17 of 20 (212 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

> Actually this is what I'm working on now, using async_tx to replace the
> memcpy. I believe the changes shouldn't be that significant.
>
> Is the "hardware that can setup dma" you refer to something that does
> not use this interface?
>

Yes, they use this interface, but split 'memcpy_toio' to two operation:
1. setup dma
2. wait/poll for the dma to finish.
So maybe it need to provide a generic function 'tx' for different hardwares.

If async_tx is available, it's much better than this 'sync dma/memcpy'.
One problem with async_tx is, it can't detect memcpy error.
If the remote ntb goes down when async_memcpy is in operation, async_tx
will trigger an oops.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


dave.jiang at intel

Jul 31, 2012, 7:18 PM

Post #18 of 20 (209 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Jul 31, 2012, at 7:10 PM, "Jianbin Kang" <kjbmail [at] gmail> wrote:

>> Actually this is what I'm working on now, using async_tx to replace the
>> memcpy. I believe the changes shouldn't be that significant.
>>
>> Is the "hardware that can setup dma" you refer to something that does
>> not use this interface?
>>
>
> Yes, they use this interface, but split 'memcpy_toio' to two operation:
> 1. setup dma
> 2. wait/poll for the dma to finish.
> So maybe it need to provide a generic function 'tx' for different hardwares.
>
It's not worth it to do sync DMA. The performance is terrible.

> If async_tx is available, it's much better than this 'sync dma/memcpy'.
> One problem with async_tx is, it can't detect memcpy error.
> If the remote ntb goes down when async_memcpy is in operation, async_tx
> will trigger an oops.

Yes that is something that needs to be addressed when we get async DMA support working. --
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


jon.mason at intel

Aug 1, 2012, 6:43 PM

Post #19 of 20 (209 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 02:02:25PM -0400, chetan loke wrote:
> On Tue, Jul 31, 2012 at 1:27 PM, Jon Mason <jon.mason [at] intel> wrote:
> >
> > I don't see the benefit of having the driver in staging. Any vendors
> > who would notice the ntb driver in staging would be sitting on these
> > mailing lists and hopefully have planety of comments on the design.
> > Stashing the driver in staging while waiting for these comments (which
> > may never come) doesn't seem the best course of action.
> >
>
> I thought that since others are talking about it then may be there is
> some WIP code for foo-NTB. Seems like that's not the case. So no need
> to stage.
>
> Correct me if I'm wrong but wouldn't apps just open a socket and route
> data via ntb_vir_eth_dev? So I don't see an ABI breakage issue and
> hence nothing would prevent us from changing the kernel parts(for
> accommodating some foo-NTB part) in future.

The virtual ethernet device (patch #2) would allow for a generic way
of passing data to the remote side. The only issue would be changing
how it is encoded in the shared buffer.

> It may not be a bad idea to prefix intel-specific(if any)
> ntb_structs/variables/logic with the 'intc'(Intel ticker or pick your
> string) keyword.

The Intel specific things are current pre-pended with "xeon" or "bwd".

Thanks,
Jon


>
> Chetan Loke
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


jon.mason at intel

Aug 1, 2012, 6:49 PM

Post #20 of 20 (214 views)
Permalink
Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support [In reply to]

On Tue, Jul 31, 2012 at 03:25:55PM -0700, Greg KH wrote:
> On Sun, Jul 29, 2012 at 05:26:33PM -0700, Jon Mason wrote:
> > +struct ntb_transport_qp;
> > +
> > +struct ntb_client {
> > + char *name;
> > + int (*probe) (struct pci_dev *pdev);
> > + void (*remove) (struct pci_dev *pdev);
> > +};
>
> Why isn't this tied into the driver model? That looks like you really
> want to use a 'struct device' here, right?
>
> Then you have drivers that bind to them, and your devices show up in
> sysfs, which is probably a requirement you have, right?

I was trying to do something more light-weight than that and avoid the
complexity, but this is probably the direction it needs to go.

Thanks,
Jon

>
> greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Linux kernel RSS feed   Index | Next | Previous | View Threaded
 
 


Interested in having your list archived? Contact Gossamer Threads
 
  Web Applications & Managed Hosting Powered by Gossamer Threads Inc.