sandybridge: add option to mark graphics memory write-combining.
The graphics memory can be accessed in a faster manner by
setting it to write-combing mode. Add an option to enable
write-combining for the graphics memory.
Change-Id: I7d37fd78906262aabef92c2b4f4cab0e3f7e4f6d
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2894
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/src/northbridge/intel/sandybridge/Kconfig b/src/northbridge/intel/sandybridge/Kconfig
index 56d2cd7..6c9ae99 100644
--- a/src/northbridge/intel/sandybridge/Kconfig
+++ b/src/northbridge/intel/sandybridge/Kconfig
@@ -107,6 +107,14 @@
hex
default 0x4000
+config MARK_GRAPHICS_MEM_WRCOMB
+ bool "Mark graphics memory as write-combining."
+ default n
+ help
+ The graphics performance may increase if the graphics
+ memory is set as write-combining cache type. This option
+ enables marking the graphics memory as write-combining.
+
config HAVE_MRC
bool "Add a System Agent binary"
help
diff --git a/src/northbridge/intel/sandybridge/gma.c b/src/northbridge/intel/sandybridge/gma.c
index b9a07a2..853139e 100644
--- a/src/northbridge/intel/sandybridge/gma.c
+++ b/src/northbridge/intel/sandybridge/gma.c
@@ -664,12 +664,29 @@
}
}
+static void gma_read_resources(struct device *dev)
+{
+ pci_dev_read_resources(dev);
+
+#if CONFIG_MARK_GRAPHICS_MEM_WRCOMB
+ struct resource *res;
+
+ /* Set the graphics memory to write combining. */
+ res = find_resource(dev, PCI_BASE_ADDRESS_2);
+ if (res == NULL) {
+ printk(BIOS_DEBUG, "gma: memory resource not found.\n");
+ return;
+ }
+ res->flags |= IORESOURCE_WRCOMB;
+#endif
+}
+
static struct pci_operations gma_pci_ops = {
.set_subsystem = gma_set_subsystem,
};
static struct device_operations gma_func0_ops = {
- .read_resources = pci_dev_read_resources,
+ .read_resources = gma_read_resources,
.set_resources = pci_dev_set_resources,
.enable_resources = pci_dev_enable_resources,
.init = gma_func0_init,