[U-Boot] [PATCH 1/3] ARM: tegra: Restrict usable RAM to 32-bit on 64-bit SoCs

[Simon Glass]

On 27 July 2015 at 11:45, Stephen Warren <swarren at wwwdotorg.org> wrote:
> From: Thierry Reding <treding at nvidia.com>
>
> Most peripherals on Tegra can do DMA only to the lower 32-bit
> address space, even on 64-bit SoCs. This limitation is
> typically overcome by the use of an IOMMU. Since the IOMMU is
> not entirely trivial to set up and serves no other purpose
> (I/O protection, ...) in U-Boot, restrict 64-bit Tegra SoCs to
> the lower 32-bit address space for RAM. This ensures that the
> physical addresses of buffers that are programmed into the
> various DMA engines are valid and don't alias to lower addresses.
>
> Signed-off-by: Thierry Reding <treding at nvidia.com>
> Signed-off-by: Tom Warren <twarren at nvidia.com>
> Signed-off-by: Stephen Warren <swarren at nvidia.com>
> ---
> These 3 patches are pre-requisites for T210 support (either compile-time
> or run-time) but don't seem to have been sent to the mailing lists
> recently.
>
>  arch/arm/mach-tegra/board2.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)

Reviewed-by: Simon Glass <sjg at chromium.org>