1 files changed, 98 insertions, 0 deletions
diff --git a/docs/plat/nvidia-tegra.rst b/docs/plat/nvidia-tegra.rst
new file mode 100644
index 00000000..7aac7e53
--- /dev/null
+++ b/docs/plat/nvidia-tegra.rst
@@ -0,0 +1,98 @@
+Tegra SoCs - Overview
+=====================
+
+-  .. rubric:: T210
+      :name: t210
+
+T210 has Quad ARM® Cortex®-A57 cores in a switched configuration with a
+companion set of quad ARM Cortex-A53 cores. The Cortex-A57 and A53 cores
+support ARMv8, executing both 64-bit Aarch64 code, and 32-bit Aarch32 code
+including legacy ARMv7 applications. The Cortex-A57 processors each have
+48 KB Instruction and 32 KB Data Level 1 caches; and have a 2 MB shared
+Level 2 unified cache. The Cortex-A53 processors each have 32 KB Instruction
+and 32 KB Data Level 1 caches; and have a 512 KB shared Level 2 unified cache.
+
+-  .. rubric:: T132
+      :name: t132
+
+Denver is NVIDIA's own custom-designed, 64-bit, dual-core CPU which is
+fully ARMv8 architecture compatible. Each of the two Denver cores
+implements a 7-way superscalar microarchitecture (up to 7 concurrent
+micro-ops can be executed per clock), and includes a 128KB 4-way L1
+instruction cache, a 64KB 4-way L1 data cache, and a 2MB 16-way L2
+cache, which services both cores.
+
+Denver implements an innovative process called Dynamic Code Optimization,
+which optimizes frequently used software routines at runtime into dense,
+highly tuned microcode-equivalent routines. These are stored in a
+dedicated, 128MB main-memory-based optimization cache. After being read
+into the instruction cache, the optimized micro-ops are executed,
+re-fetched and executed from the instruction cache as long as needed and
+capacity allows.
+
+Effectively, this reduces the need to re-optimize the software routines.
+Instead of using hardware to extract the instruction-level parallelism
+(ILP) inherent in the code, Denver extracts the ILP once via software
+techniques, and then executes those routines repeatedly, thus amortizing
+the cost of ILP extraction over the many execution instances.
+
+Denver also features new low latency power-state transitions, in addition
+to extensive power-gating and dynamic voltage and clock scaling based on
+workloads.
+
+Directory structure
+===================
+
+-  plat/nvidia/tegra/common - Common code for all Tegra SoCs
+-  plat/nvidia/tegra/soc/txxx - Chip specific code
+
+Trusted OS dispatcher
+=====================
+
+Tegra supports multiple Trusted OS', Trusted Little Kernel (TLK) being one of
+them. In order to include the 'tlkd' dispatcher in the image, pass 'SPD=tlkd'
+on the command line while preparing a bl31 image. This allows other Trusted OS
+vendors to use the upstream code and include their dispatchers in the image
+without changing any makefiles.
+
+Preparing the BL31 image to run on Tegra SoCs
+=============================================
+
+.. code:: shell
+
+    CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-none-elf- make PLAT=tegra \
+    TARGET_SOC=<target-soc e.g. t210|t132> SPD=<dispatcher e.g. tlkd> bl31
+
+Platforms wanting to use different TZDRAM\_BASE, can add ``TZDRAM_BASE=<value>``
+to the build command line.
+
+The Tegra platform code expects a pointer to the following platform specific
+structure via 'x1' register from the BL2 layer which is used by the
+bl31\_early\_platform\_setup() handler to extract the TZDRAM carveout base and
+size for loading the Trusted OS and the UART port ID to be used. The Tegra
+memory controller driver programs this base/size in order to restrict NS
+accesses.
+
+typedef struct plat\_params\_from\_bl2 {
+/\* TZ memory size */
+uint64\_t tzdram\_size;
+/* TZ memory base */
+uint64\_t tzdram\_base;
+/* UART port ID \*/
+int uart\_id;
+} plat\_params\_from\_bl2\_t;
+
+Power Management
+================
+
+The PSCI implementation expects each platform to expose the 'power state'
+parameter to be used during the 'SYSTEM SUSPEND' call. The state-id field
+is implementation defined on Tegra SoCs and is preferably defined by
+tegra\_def.h.
+
+Tegra configs
+=============
+
+-  'tegra\_enable\_l2\_ecc\_parity\_prot': This flag enables the L2 ECC and Parity
+   Protection bit, for ARM Cortex-A57 CPUs, during CPU boot. This flag will
+   be enabled by Tegrs SoCs during 'Cluster power up' or 'System Suspend' exit.