[S] Change in coreboot[master]: drivers/emulation/qemu/bochs: Fix the MMIO access to the VGA ioports

[Felix Singer (Code Review)]

Felix Singer has submitted this change. ( https://review.coreboot.org/c/coreboot/+/75146 )

Change subject: drivers/emulation/qemu/bochs: Fix the MMIO access to the VGA ioports
......................................................................

drivers/emulation/qemu/bochs: Fix the MMIO access to the VGA ioports

The Bochs graphics adapter remaps the legacy VGA ioports
(0x3c0 -> 0x3df) to its MMIO region at offsets 0400 - 041f.
Currently bochs_vga_write() calculates a wrong offset when
accessing these ioports, which causes the boot splash image
not displayed when using the legacy-free pci variant of the
Bochs graphics adapter.

TEST=Build coreboot for QEMU x86 i440fx with a boot splash image
included, boot coreboot.rom with QEMU with '-device secondary-vga'
and verify the boot splash image is correctly displayed.

Fixes: efaf1b32ba1e ("drivers/emulation/qemu/bochs: Rewrite driver")
Signed-off-by: Bin Meng 
Change-Id: I4acc71e3d6ef5161ab62e6714c94b7643c4c0972
Reviewed-on: https://review.coreboot.org/c/coreboot/+/75146
Reviewed-by: Gerd Hoffmann 
Tested-by: build bot (Jenkins) 
Reviewed-by: Nico Huber 
Reviewed-by: Felix Singer 
---
M src/drivers/emulation/qemu/bochs.c
1 file changed, 28 insertions(+), 1 deletion(-)

Approvals:
  build bot (Jenkins): Verified
  Nico Huber: Looks good to me, but someone else must approve
  Gerd Hoffmann: Looks good to me, but someone else must approve
  Felix Singer: Looks good to me, approved

diff --git a/src/drivers/emulation/qemu/bochs.c b/src/drivers/emulation/qemu/bochs.c
index 4634021..0650430 100644
--- a/src/drivers/emulation/qemu/bochs.c
+++ b/src/drivers/emulation/qemu/bochs.c
@@ -67,7 +67,7 @@
    if (res->flags & IORESOURCE_IO)
    	outb(val, index + 0x3c0);
    else
-		write8(res2mmio(res, (0x400 - 0x3c0) + index, 0), val);
+		write8(res2mmio(res, 0x400 + index, 0), val);
 }

static struct resource res_legacy = {