[U-Boot] [PATCH 1/6] x86: Support machines with >4GB of RAM

[Bin Meng]

Hi Simon,

On Wed, Feb 11, 2015 at 9:59 AM, Simon Glass <sjg at chromium.org> wrote:
> Some systems have more than 4GB of RAM. U-Boot can only place things below
> 4GB so any memory above that should not be used. Ignore any such memory so
> that the memory size will not exceed the maximum.
>
> This prevents gd->ram_size exceeding 4GB which causes problems for PCI
> devices which use DMA.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
>  arch/x86/cpu/coreboot/sdram.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/cpu/coreboot/sdram.c b/arch/x86/cpu/coreboot/sdram.c
> index e98a230..9c3ab81 100644
> --- a/arch/x86/cpu/coreboot/sdram.c
> +++ b/arch/x86/cpu/coreboot/sdram.c
> @@ -90,7 +90,8 @@ int dram_init(void)
>                 struct memrange *memrange = &lib_sysinfo.memrange[i];
>                 unsigned long long end = memrange->base + memrange->size;
>
> -               if (memrange->type == CB_MEM_RAM && end > ram_size)
> +               if (memrange->type == CB_MEM_RAM && end > ram_size &&
> +                   memrange->base < (1ULL << 32))

Can we safely assume no single entry in memrange[] lies across the 4GB boundary?

>                         ram_size = end;
>         }
>         gd->ram_size = ram_size;
> @@ -108,7 +109,8 @@ void dram_init_banksize(void)
>                 for (i = 0, j = 0; i < lib_sysinfo.n_memranges; i++) {
>                         struct memrange *memrange = &lib_sysinfo.memrange[i];
>
> -                       if (memrange->type == CB_MEM_RAM) {
> +                       if (memrange->type == CB_MEM_RAM &&
> +                           memrange->base < (1ULL << 32)) {
>                                 gd->bd->bi_dram[j].start = memrange->base;
>                                 gd->bd->bi_dram[j].size = memrange->size;
>                                 j++;
> --

Regards,
Bin