[U-Boot] [PATCH 18/22][v2] armv8/ls2085a: Update SoC README for DDR layout

Prabhakar Kushwaha
2015-05-28T09:24:11Z

Update SoC README to provide details of
- Memory regions
- Memory used by MC and Debug server

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@freescale.com>
Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
---
Chanes for v2: New patch

arch/arm/cpu/armv8/fsl-lsch3/README | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

diff --git a/arch/arm/cpu/armv8/fsl-lsch3/README b/arch/arm/cpu/armv8/fsl-lsch3/README
index 37f07fb..3c15479 100644
--- a/arch/arm/cpu/armv8/fsl-lsch3/README
+++ b/arch/arm/cpu/armv8/fsl-lsch3/README
@@ -9,6 +9,31 @@ Freescale LayerScape with Chassis Generation 3
This architecture supports Freescale ARMv8 SoCs with Chassis generation 3,
for example LS2085A.

+DDR Layout
+============
+Entire DDR region splits into two regions.
+ - Region 1 is at address 0x8000_0000 to 0xffff_ffff.
+ - Region 2 is at 0x80_8000_0000 to the top of total memory,
+ for example 16GB, 0x83_ffff_ffff.
+
+All DDR memory is marked as cache-enabled.
+
+When MC and Debug server is enabled, they carve 512MB away from the high
+end of DDR. For example, if the total DDR is 16GB, it shrinks to 15.5GB
+with MC and Debug server enabled. Linux only sees 15.5GB.
+
+The reserved 512MB layout looks like
+
+ +---------------+ <-- top/end of memory
+ | 256MB | debug server
+ +---------------+
+ | 256MB | MC
+ +---------------+
+ | ... |
+
+MC requires the memory to be aligned with 512MB, so even debug server is
+not enabled, 512MB is reserved, not 256MB.
+
Flash Layout
============

--
1.9.1