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x86: ivybridge: Set up an MTRR for the video frame buffer

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Set the frame buffer to write-combining. This makes it faster, although for
scrolling write-through is even faster for U-Boot.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2015-01-01 16:18:08 -07:00
parent aff2523f69
commit 9818a00eea
1 changed files with 7 additions and 0 deletions
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7
arch/x86/cpu/ivybridge/gma.c
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@ -12,6 +12,7 @@
#include <fdtdec.h>
#include <pci_rom.h>
#include <asm/io.h>
#include <asm/mtrr.h>
#include <asm/pci.h>
#include <asm/arch/pch.h>
#include <asm/arch/sandybridge.h>
@ -735,6 +736,7 @@ int gma_func0_init(pci_dev_t dev, struct pci_controller *hose,
ulong start;
#endif
void *gtt_bar;
ulong base;
u32 reg32;
int ret;
@ -743,6 +745,11 @@ int gma_func0_init(pci_dev_t dev, struct pci_controller *hose,
reg32 |= PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY | PCI_COMMAND_IO;
pci_write_config32(dev, PCI_COMMAND, reg32);
/* Use write-combining for the graphics memory, 256MB */
base = pci_read_bar32(hose, dev, 2);
mtrr_add_request(MTRR_TYPE_WRCOMB, base, 256 << 20);
mtrr_commit(true);
gtt_bar = (void *)pci_read_bar32(pci_bus_to_hose(0), dev, 0);
debug("GT bar %p\n", gtt_bar);
ret = gma_pm_init_pre_vbios(gtt_bar);