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| author | Andrew Cooper <andrew.cooper3@citrix.com> | 2013-08-06 14:48:37 +0100 |
|---|---|---|
| committer | Ian Campbell <ian.campbell@citrix.com> | 2013-08-08 12:03:12 +0100 |
| commit | 413a6fb4ee81897acafefb90f81ef3d2661c3aa6 (patch) | |
| tree | 2f386a9ef5e50efa2cdf1510c8176a2641a7ed35 /tools/firmware | |
| parent | 20025504271220ab3bf041955a3cd40c6057e58e (diff) | |
| download | xen-413a6fb4ee81897acafefb90f81ef3d2661c3aa6.tar.gz xen-413a6fb4ee81897acafefb90f81ef3d2661c3aa6.tar.bz2 xen-413a6fb4ee81897acafefb90f81ef3d2661c3aa6.zip | |
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@citrix.com>
Acked-by: Keir Fraser <keir@xen.org>
Diffstat (limited to 'tools/firmware')
| -rw-r--r-- | 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 e364759b3b..a3efc618e0 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); |