of: Document timings subnode of nvidia,tegra-mc

The MC driver needs some timing-specific information to program the EMEM
during a rate change of the EMC clock.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
This commit is contained in:
Tomeu Vizoso 2015-03-12 15:47:57 +01:00 committed by Thierry Reding
parent d555a1a128
commit 101197c39b

View File

@ -1,6 +1,9 @@
NVIDIA Tegra Memory Controller device tree bindings
===================================================
memory-controller node
----------------------
Required properties:
- compatible: Should be "nvidia,tegra<chip>-mc"
- reg: Physical base address and length of the controller's registers.
@ -15,9 +18,49 @@ Required properties:
This device implements an IOMMU that complies with the generic IOMMU binding.
See ../iommu/iommu.txt for details.
Example:
--------
emc-timings subnode
-------------------
The node should contain a "emc-timings" subnode for each supported RAM type (see field RAM_CODE in
register PMC_STRAPPING_OPT_A).
Required properties for "emc-timings" nodes :
- nvidia,ram-code : Should contain the value of RAM_CODE this timing set is used for.
timing subnode
--------------
Each "emc-timings" node should contain a subnode for every supported EMC clock rate.
Required properties for timing nodes :
- clock-frequency : Should contain the memory clock rate in Hz.
- nvidia,emem-configuration : Values to be written to the EMEM register block. For the Tegra124 SoC
(see section "15.6.1 MC Registers" in the TRM), these are the registers whose values need to be
specified, according to the board documentation:
MC_EMEM_ARB_CFG
MC_EMEM_ARB_OUTSTANDING_REQ
MC_EMEM_ARB_TIMING_RCD
MC_EMEM_ARB_TIMING_RP
MC_EMEM_ARB_TIMING_RC
MC_EMEM_ARB_TIMING_RAS
MC_EMEM_ARB_TIMING_FAW
MC_EMEM_ARB_TIMING_RRD
MC_EMEM_ARB_TIMING_RAP2PRE
MC_EMEM_ARB_TIMING_WAP2PRE
MC_EMEM_ARB_TIMING_R2R
MC_EMEM_ARB_TIMING_W2W
MC_EMEM_ARB_TIMING_R2W
MC_EMEM_ARB_TIMING_W2R
MC_EMEM_ARB_DA_TURNS
MC_EMEM_ARB_DA_COVERS
MC_EMEM_ARB_MISC0
MC_EMEM_ARB_MISC1
MC_EMEM_ARB_RING1_THROTTLE
Example SoC include file:
/ {
mc: memory-controller@0,70019000 {
compatible = "nvidia,tegra124-mc";
reg = <0x0 0x70019000 0x0 0x1000>;
@ -34,3 +77,40 @@ Example:
...
iommus = <&mc TEGRA_SWGROUP_SDMMC1A>;
};
};
Example board file:
/ {
memory-controller@0,70019000 {
emc-timings-3 {
nvidia,ram-code = <3>;
timing-12750000 {
clock-frequency = <12750000>;
nvidia,emem-configuration = <
0x40040001 /* MC_EMEM_ARB_CFG */
0x8000000a /* MC_EMEM_ARB_OUTSTANDING_REQ */
0x00000001 /* MC_EMEM_ARB_TIMING_RCD */
0x00000001 /* MC_EMEM_ARB_TIMING_RP */
0x00000002 /* MC_EMEM_ARB_TIMING_RC */
0x00000000 /* MC_EMEM_ARB_TIMING_RAS */
0x00000002 /* MC_EMEM_ARB_TIMING_FAW */
0x00000001 /* MC_EMEM_ARB_TIMING_RRD */
0x00000002 /* MC_EMEM_ARB_TIMING_RAP2PRE */
0x00000008 /* MC_EMEM_ARB_TIMING_WAP2PRE */
0x00000003 /* MC_EMEM_ARB_TIMING_R2R */
0x00000002 /* MC_EMEM_ARB_TIMING_W2W */
0x00000003 /* MC_EMEM_ARB_TIMING_R2W */
0x00000006 /* MC_EMEM_ARB_TIMING_W2R */
0x06030203 /* MC_EMEM_ARB_DA_TURNS */
0x000a0402 /* MC_EMEM_ARB_DA_COVERS */
0x77e30303 /* MC_EMEM_ARB_MISC0 */
0x70000f03 /* MC_EMEM_ARB_MISC1 */
0x001f0000 /* MC_EMEM_ARB_RING1_THROTTLE */
>;
};
};
};
};