I may have misunderstood the flags as being valid ways of mapping the added range. Should we also then take out WC and WT?
From: Jeremy Linton <jeremy.linton@arm.com>
Sent: Friday, October 1, 2021 7:52 PM
To: devel@edk2.groups.io <devel@edk2.groups.io>
Cc: pete@akeo.ie <pete@akeo.ie>; ardb+tianocore@kernel.org <ardb+tianocore@kernel.org>; leif@nuviainc.com <leif@nuviainc.com>; Andrei Warkentin <awarkentin@vmware.com>; Sunny.Wang@arm.com <Sunny.Wang@arm.com>; samer.el-haj-mahmoud@arm.com <samer.el-haj-mahmoud@arm.com>; Jeremy Linton <jeremy.linton@arm.com>
Subject: [PATCH 4/5] Platform/RaspberryPi: Normal memory should not be marked as uncached
 
The efi spec seems to indicate that the efi uncacheable attribute
should be mapped to device memory rather than normal-nc. This means
that the uefi mem attribute for the >3G ram doesn't match the remainder
of the RAM in the machine.

So, lets remove the uncacheable attribute to make it more consistent.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
---
 Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
index 2ef7da67bd..415d99fadb 100644
--- a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
+++ b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
@@ -499,7 +499,7 @@ ApplyVariables (
 
     Status = gDS->AddMemorySpace (EfiGcdMemoryTypeSystemMemory, 3UL * BASE_1GB,
                     SystemMemorySizeBelow4GB - (3UL * SIZE_1GB),
-                    EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB);
+                    EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB);
     ASSERT_EFI_ERROR (Status);
     Status = gDS->SetMemorySpaceAttributes (3UL * BASE_1GB,
                     SystemMemorySizeBelow4GB - (3UL * SIZE_1GB), EFI_MEMORY_WB);
@@ -511,7 +511,7 @@ ApplyVariables (
       //
       Status = gDS->AddMemorySpace (EfiGcdMemoryTypeSystemMemory, 4UL * BASE_1GB,
                       SystemMemorySize - (4UL * SIZE_1GB),
-                      EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB);
+                      EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB);
       ASSERT_EFI_ERROR (Status);
       Status = gDS->SetMemorySpaceAttributes (4UL * BASE_1GB,
                       SystemMemorySize - (4UL * SIZE_1GB), EFI_MEMORY_WB);
--
2.13.7