patchbot at xen
Aug 8, 2013, 10:22 PM
Post #1 of 1
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[xen master] rombios/ata: Do not wait for BSY to be set
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commit 413a6fb4ee81897acafefb90f81ef3d2661c3aa6
Author: Andrew Cooper <andrew.cooper3 [at] citrix>
AuthorDate: Tue Aug 6 14:48:37 2013 +0100
Commit: Ian Campbell <ian.campbell [at] citrix>
CommitDate: Thu Aug 8 12:03:12 2013 +0100
rombios/ata: Do not wait for BSY to be set
After issuing a reset, the BSY bit is expected to be set. This is not the
case for Qemu.
In SeaBIOS.git: 580e33293244fee4556e56ecc67b8bd877f3c496
this check was even replaced with a udelay(5), as enough real hardware ignored
the BSY bit as well.
As rombios does not have an equivalent udelay(), replace the wait with a write
to port 0x80 which is whitelisted by Xen for 'a small delay'.
This causes 42k fewer IO traps to Qemu.
Signed-off-by: Andrew Cooper <andrew.cooper3 [at] citrix>
Acked-by: Keir Fraser <keir [at] xen>
---
tools/firmware/rombios/rombios.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/firmware/rombios/rombios.c b/tools/firmware/rombios/rombios.c
index e364759..a3efc61 100644
--- a/tools/firmware/rombios/rombios.c
+++ b/tools/firmware/rombios/rombios.c
@@ -2914,8 +2914,8 @@ Bit16u device;
// 8.2.1 (a) -- set SRST in DC
outb(iobase2+ATA_CB_DC, ATA_CB_DC_HD15 | ATA_CB_DC_NIEN | ATA_CB_DC_SRST);
-// 8.2.1 (b) -- wait for BSY
- await_ide(BSY, iobase1, 20);
+// 8.2.1 (b) -- wait
+ outb(0x80, 0x00);
// 8.2.1 (f) -- clear SRST
outb(iobase2+ATA_CB_DC, ATA_CB_DC_HD15 | ATA_CB_DC_NIEN);
--
generated by git-patchbot for /home/xen/git/xen.git#master
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