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authorAaron Durbin <adurbin@chromium.org>2014-02-08 15:41:52 -0600
committerAaron Durbin <adurbin@google.com>2014-02-09 22:08:53 +0100
commitca4f4b8c9eef77fbcad0af3b21885a337a1f2c83 (patch)
treed6d185b7a25c9a1f8c0e6105f34178cb0658ba71 /src/cpu/x86/mtrr
parent892728c65fcd82cab43e334396b86fc257ecf256 (diff)
downloadcoreboot-ca4f4b8c9eef77fbcad0af3b21885a337a1f2c83.tar.xz
mtrr: only add prefetchable resources as WRCOMB for VGA devices
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)
Diffstat (limited to 'src/cpu/x86/mtrr')
-rw-r--r--src/cpu/x86/mtrr/mtrr.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/src/cpu/x86/mtrr/mtrr.c b/src/cpu/x86/mtrr/mtrr.c
index dfb9c94eeb..d85a86982c 100644
--- a/src/cpu/x86/mtrr/mtrr.c
+++ b/src/cpu/x86/mtrr/mtrr.c
@@ -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