Mailing List Archive: Linux: Kernel

[PATCH v4 03/16] [loongson] early_printk: add new implmentation

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wuzhangjin at gmail

Jul 2, 2009, 8:20 AM

Post #1 of 3 (173 views)
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[PATCH v4 03/16] [loongson] early_printk: add new implmentation

From: Wu Zhangjin <wuzj [at] lemote>

This patch is based on the implementation in the lm2e-fixes branch of
Philippe's git://git.linux-cisco.org/linux-mips.git and the
malta-specific early_printk implementation.

Signed-off-by: Wu Zhangjin <wuzj [at] lemote>
---
arch/mips/lemote/lm2e/Makefile | 5 ++++
arch/mips/lemote/lm2e/early_printk.c | 41 ++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+), 0 deletions(-)
create mode 100644 arch/mips/lemote/lm2e/early_printk.c

diff --git a/arch/mips/lemote/lm2e/Makefile b/arch/mips/lemote/lm2e/Makefile
index b0c0339..f191732 100644
--- a/arch/mips/lemote/lm2e/Makefile
+++ b/arch/mips/lemote/lm2e/Makefile
@@ -4,4 +4,9 @@

obj-y += setup.o prom.o reset.o irq.o pci.o bonito-irq.o mem.o

+#
+# Early printk support
+#
+obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
+
EXTRA_CFLAGS += -Werror
diff --git a/arch/mips/lemote/lm2e/early_printk.c b/arch/mips/lemote/lm2e/early_printk.c
new file mode 100644
index 0000000..811c7de
--- /dev/null
+++ b/arch/mips/lemote/lm2e/early_printk.c
@@ -0,0 +1,41 @@
+/* early printk support
+ *
+ * Copyright (c) 2009 Philippe Vachon <philippe [at] cowpig>
+ * Copyright (C) 2009 Lemote Inc. & Insititute of Computing Technology
+ * Author: Wu Zhangjin, wuzj [at] lemote
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/serial_reg.h>
+
+#include <asm/mips-boards/bonito64.h>
+
+#define UART_BASE (BONITO_PCIIO_BASE + 0x3f8)
+
+#define PORT(base, offset) (u8 *)(base + offset)
+
+static inline unsigned int serial_in(phys_addr_t base, int offset)
+{
+ return readb(PORT(base, offset));
+}
+
+static inline void serial_out(phys_addr_t base, int offset, int value)
+{
+ writeb(value, PORT(base, offset));
+}
+
+void prom_putchar(char c)
+{
+ phys_addr_t uart_base =
+ (phys_addr_t) ioremap_nocache(UART_BASE, 8);
+
+ while ((serial_in(uart_base, UART_LSR) & UART_LSR_THRE) == 0)
+ ;
+
+ serial_out(uart_base, UART_TX, c);
+}
--
1.6.2.1

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ralf at linux-mips

Jul 6, 2009, 3:43 AM

Post #2 of 3 (158 views)
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Re: [PATCH v4 03/16] [loongson] early_printk: add new implmentation [In reply to]

On Thu, Jul 02, 2009 at 11:20:20PM +0800, Wu Zhangjin wrote:

> +#include <asm/mips-boards/bonito64.h>
> +
> +#define UART_BASE (BONITO_PCIIO_BASE + 0x3f8)
> +
> +#define PORT(base, offset) (u8 *)(base + offset)
> +
> +static inline unsigned int serial_in(phys_addr_t base, int offset)
> +{
> + return readb(PORT(base, offset));
> +}
> +
> +static inline void serial_out(phys_addr_t base, int offset, int value)
> +{
> + writeb(value, PORT(base, offset));

Why not inb(0x3f8, + offset) rsp. outb()?

> +}
> +
> +void prom_putchar(char c)
> +{
> + phys_addr_t uart_base =
> + (phys_addr_t) ioremap_nocache(UART_BASE, 8);

ioremap_nocache returns a virtual address, not a physical address, so
this type should probably be unsigned char *.

> + while ((serial_in(uart_base, UART_LSR) & UART_LSR_THRE) == 0)

Ralf
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wuzhangjin at gmail

Jul 6, 2009, 6:57 AM

Post #3 of 3 (155 views)
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Re: [PATCH v4 03/16] [loongson] early_printk: add new implmentation [In reply to]

On Mon, 2009-07-06 at 11:43 +0100, Ralf Baechle wrote:
> On Thu, Jul 02, 2009 at 11:20:20PM +0800, Wu Zhangjin wrote:
>
> > +#include <asm/mips-boards/bonito64.h>
> > +
> > +#define UART_BASE (BONITO_PCIIO_BASE + 0x3f8)
> > +
> > +#define PORT(base, offset) (u8 *)(base + offset)
> > +
> > +static inline unsigned int serial_in(phys_addr_t base, int offset)
> > +{
> > + return readb(PORT(base, offset));
> > +}
> > +
> > +static inline void serial_out(phys_addr_t base, int offset, int value)
> > +{
> > + writeb(value, PORT(base, offset));
>
> Why not inb(0x3f8, + offset) rsp. outb()?
>

because yeeloong laptop use the serial port of cpu, which have different
base address: 0x1ff000000 + 0x3f8, to share the same source code between
yeeloong, fuloong2f(0x1fd00000 + 0x2f8) and fuloong2e(0x1fd00000 +
0x3f8), I use PORT(base, offset) here and use readb/writeb instead of
inb/outb. so, here is only a preparation for future yeeloong2f support.

> > +}
> > +
> > +void prom_putchar(char c)
> > +{
> > + phys_addr_t uart_base =
> > + (phys_addr_t) ioremap_nocache(UART_BASE, 8);
>
> ioremap_nocache returns a virtual address, not a physical address, so
> this type should probably be unsigned char *.
>

okay, I will change it.

Thanks!
Wu Zhangjin

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