[U-Boot] [PATCH 089/126] x86: Set up the MTRR for SDRAM

[Bin Meng]

On Wed, Sep 25, 2019 at 10:59 PM Simon Glass <sjg at chromium.org> wrote:
>
> Set up MTRRs for the FST SDRAM regions to improve performance.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
>  arch/x86/lib/fsp/fsp_dram.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/lib/fsp/fsp_dram.c b/arch/x86/lib/fsp/fsp_dram.c
> index 9161af65b98..4a87516f422 100644
> --- a/arch/x86/lib/fsp/fsp_dram.c
> +++ b/arch/x86/lib/fsp/fsp_dram.c
> @@ -8,6 +8,7 @@
>  #include <asm/fsp/fsp_support.h>
>  #include <asm/e820.h>
>  #include <asm/mrccache.h>
> +#include <asm/mtrr.h>
>  #include <asm/post.h>
>
>  DECLARE_GLOBAL_DATA_PTR;
> @@ -70,6 +71,8 @@ int dram_init_banksize(void)
>         gd->bd->bi_dram[0].start = 0;
>         gd->bd->bi_dram[0].size = low_end;
>
> +       mtrr_add_request(MTRR_TYPE_WRBACK, 0, low_end);

I suspect we don't need explicit MTRR configuration. I see on the FSP
1.0 boards, MTRR is already programmed by FSP.

But I am fine adding this. So if we are adding this MTRR, please also
move MTRR programming from previous patch ([088/126] x86: Set the DRAM
banks to reflect real location) to this patch.

> +
>         return 0;

Regards,
Bin