[PATCH edk2-platforms v2 16/18] ARM/JunoPkg: Mapping Non-Trused SRAM as device memory

[evan.lloyd@arm.com]

From: Girish Pathak <girish.pathak@arm.com>

This fix changes the cache attribute of Non-Trusted SRAM on the Juno
platform to device memory. This change is required to avoid coherency
problems as Non-Trusted SRAM is used as a shared memory between the
application processor and the SCP for communication. This change is a
prerequisite for upcoming SCMI driver for the Juno platform.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Girish Pathak <girish.pathak@arm.com>
---
 Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c b/Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c
index aa8d7d9c3b0d41e62d1849e6e88760e3066617f7..afb2db0050c65b0d1b2b69c9038e168755c152c1 100644
--- a/Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c
+++ b/Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c
@@ -1,6 +1,6 @@
 /** @file
 *
-*  Copyright (c) 2013-2015, ARM Limited. All rights reserved.
+*  Copyright (c) 2013-2017, ARM Limited. All rights reserved.
 *
 *  This program and the accompanying materials
 *  are licensed and made available under the terms and conditions of the BSD License
@@ -111,7 +111,9 @@ ArmPlatformGetVirtualMemoryMap (
   VirtualMemoryTable[++Index].PhysicalBase  = ARM_JUNO_NON_SECURE_SRAM_BASE;
   VirtualMemoryTable[Index].VirtualBase     = ARM_JUNO_NON_SECURE_SRAM_BASE;
   VirtualMemoryTable[Index].Length          = ARM_JUNO_NON_SECURE_SRAM_SZ;
-  VirtualMemoryTable[Index].Attributes      = CacheAttributes;
+  // This memory is shared between the application processor
+  // and the SCP. To avoid coherency problems, map it as device memory.
+  VirtualMemoryTable[Index].Attributes      = ARM_MEMORY_REGION_ATTRIBUTE_DEVICE;
 
   // PCI Root Complex
   VirtualMemoryTable[++Index].PhysicalBase  = PcdGet64 (PcdPcieControlBaseAddress);
-- 
Guid("CE165669-3EF3-493F-B85D-6190EE5B9759")