ARM: tegra: Restrict usable RAM to 32-bit on 64-bit SoCs
authorThierry Reding <treding@nvidia.com>
Mon, 27 Jul 2015 17:45:24 +0000 (11:45 -0600)
committerTom Warren <twarren@nvidia.com>
Tue, 28 Jul 2015 17:30:17 +0000 (10:30 -0700)
commit00f782a9f82a20b2fe4bf6c254758e6ac94ddb15
tree01dff9aac53b05360cf391544ed6824859defff0
parent5b34436035fc862b5e8d0d2c3eab74ba36f1a7f4
ARM: tegra: Restrict usable RAM to 32-bit on 64-bit SoCs

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@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
arch/arm/mach-tegra/board2.c