Hi Simon,
On Sun, Dec 28, 2014 at 10:20 AM, Simon Glass <s...@chromium.org> wrote:
> 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 <s...@chromium.org>
> ---
>
> arch/x86/cpu/ivybridge/gma.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/arch/x86/cpu/ivybridge/gma.c b/arch/x86/cpu/ivybridge/gma.c
> index 125021b..03b2ebd 100644
> --- a/arch/x86/cpu/ivybridge/gma.c
> +++ b/arch/x86/cpu/ivybridge/gma.c
> @@ -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>
> @@ -738,6 +739,8 @@ int gma_func0_init(pci_dev_t dev, struct pci_controller
> *hose,
> const void *blob, int node)
> {
> void *gtt_bar;
> + ulong start;
> + ulong base;
> u32 reg32;
> int ret;
>
> @@ -746,6 +749,11 @@ 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);
To make the codes more generic, should we decode the memory size via
bar instead of hardcoded 256MB?
> + 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);
> --
Regards,
Bin
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