sravan/system76-coreboot
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

mtrr: only add prefetchable resources as WRCOMB for VGA devices

Browse Source 
Be more conservative and only add VGA devices' prefetchable
resources as write-combining in the address space. Previously
all prefetchable memory was added as a write-combining memory
type. Some hardware incorrectly advertises its BAR as
prefetchable when it shouldn't be.

A new memranges_add_resources_filter() function is added
to provide additional filtering on device and resource.

Change-Id: I3fc55b90d8c5b694c5aa9e2f34db1b4ef845ce10
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/5169
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
Tested-by: build bot (Jenkins)
This commit is contained in:
Aaron Durbin
2014-02-08 15:41:52 -06:00
committed by Aaron Durbin
parent 892728c65f
commit ca4f4b8c9e
3 changed files with 45 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
src/cpu/x86/mtrr/mtrr.c
View File

@@ -30,6 +30,7 @@
#include <bootstate.h>
#include <console/console.h>
#include <device/device.h>
#include <device/pci_ids.h>
#include <cpu/cpu.h>
#include <cpu/x86/msr.h>
#include <cpu/x86/mtrr.h>
@@ -154,6 +155,20 @@ static inline int range_entry_mtrr_type(struct range_entry *r)
return range_entry_tag(r) & MTRR_TAG_MASK;
}
static int filter_vga_wrcomb(struct device *dev, struct resource *res)
{
/* Only handle PCI devices. */
if (dev->path.type != DEVICE_PATH_PCI)
return 0;
/* Only handle VGA class devices. */
if (((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA))
return 0;
/* Add resource as write-combining in the address space. */
return 1;
}
static struct memranges *get_physical_address_space(void)
{
static struct memranges *addr_space;
@@ -181,8 +196,8 @@ static struct memranges *get_physical_address_space(void)
* resources are appropriate for this MTRR type. */
match = IORESOURCE_PREFETCH;
mask |= match;
memranges_add_resources(addr_space, mask, match,
MTRR_TYPE_WRCOMB);
memranges_add_resources_filter(addr_space, mask, match, MTRR_TYPE_WRCOMB,
filter_vga_wrcomb);
#if CONFIG_CACHE_ROM
/* Add a write-protect region covering the ROM size