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memory: Add NVIDIA Tegra memory controller support
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The memory controller on NVIDIA Tegra exposes various knobs that can be
used to tune the behaviour of the clients attached to it.

Currently this driver sets up the latency allowance registers to the HW
defaults. Eventually an API should be exported by this driver (via a
custom API or a generic subsystem) to allow clients to register latency
requirements.

This driver also registers an IOMMU (SMMU) that's implemented by the
memory controller. It is supported on Tegra30, Tegra114 and Tegra124
currently. Tegra20 has a GART instead.

The Tegra SMMU operates on memory clients and SWGROUPs. A memory client
is a unidirectional, special-purpose DMA master. A SWGROUP represents a
set of memory clients that form a logical functional unit corresponding
to a single device. Typically a device has two clients: one client for
read transactions and one client for write transactions, but there are
also devices that have only read clients, but many of them (such as the
display controllers).

Because there is no 1:1 relationship between memory clients and devices
the driver keeps a table of memory clients and the SWGROUPs that they
belong to per SoC. Note that this is an exception and due to the fact
that the SMMU is tightly integrated with the rest of the Tegra SoC. The
use of these tables is discouraged in drivers for generic IOMMU devices
such as the ARM SMMU because the same IOMMU could be used in any number
of SoCs and keeping such tables for each SoC would not scale.

Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
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Thierry Reding committed Dec 4, 2014
1 parent 4bc567d commit 8918465
Showing 16 changed files with 3,988 additions and 1,482 deletions.
12 changes: 6 additions & 6 deletions drivers/iommu/Kconfig
Original file line number Diff line number Diff line change
@@ -163,14 +163,14 @@ config TEGRA_IOMMU_GART
hardware included on Tegra SoCs.

config TEGRA_IOMMU_SMMU
bool "Tegra SMMU IOMMU Support"
depends on ARCH_TEGRA && TEGRA_AHB
bool "NVIDIA Tegra SMMU Support"
depends on ARCH_TEGRA
depends on TEGRA_AHB
depends on TEGRA_MC
select IOMMU_API
help
Enables support for remapping discontiguous physical memory
shared with the operating system into contiguous I/O virtual
space through the SMMU (System Memory Management Unit)
hardware included on Tegra SoCs.
This driver supports the IOMMU hardware (SMMU) found on NVIDIA Tegra
SoCs (Tegra30 up to Tegra124).

config EXYNOS_IOMMU
bool "Exynos IOMMU Support"
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