[PATCH v3 edk2-platforms 1/5] Platform/ARM/Sgi: Adapt to changes in system-id DT node.

[Chandni Cherukuri <chandni.cherukuri@arm.com>]

The 'system-id' node of HW_CONFIG device tree has been updated to have
a new property 'config-id' to hold the platform configuration value.
Prior to this, configuration ID value was represented by the the upper
four bits of the 'platform ID' property value but it now has a seperate
property of its own in the 'system-id' node. So adapt to these changes
in the 'system-id' node.

Contributed-under: TianoCore Contribution Agreement 1.1
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
---
 Platform/ARM/SgiPkg/Library/SgiPlatformPei/SgiPlatformPeim.c | 24 +++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/Platform/ARM/SgiPkg/Library/SgiPlatformPei/SgiPlatformPeim.c b/Platform/ARM/SgiPkg/Library/SgiPlatformPei/SgiPlatformPeim.c
index 081d329..5bdf20c 100644
--- a/Platform/ARM/SgiPkg/Library/SgiPlatformPei/SgiPlatformPeim.c
+++ b/Platform/ARM/SgiPkg/Library/SgiPlatformPei/SgiPlatformPeim.c
@@ -42,6 +42,8 @@ GetSgiPlatformId (
   CONST VOID                    *HwCfgDtBlob;
   SGI_HW_CONFIG_INFO_PPI        *HwConfigInfoPpi;
   EFI_STATUS                    Status;
+  UINT32                        PlatformId;
+  UINT32                        ConfigId;
 
   Status = PeiServicesLocatePpi (&gHwConfigDtInfoPpiGuid, 0, NULL,
              (VOID**)&HwConfigInfoPpi);
@@ -69,7 +71,27 @@ GetSgiPlatformId (
     return 0;
   }
 
-  return fdt32_to_cpu (*Property);
+  PlatformId = fdt32_to_cpu (*Property);
+
+  // Ensure upper 4-bits of platform-id is set to zero.
+  ASSERT ((PlatformId >> SGI_CONFIG_SHIFT) == 0);
+
+  Property = fdt_getprop (HwCfgDtBlob, Offset, "config-id", NULL);
+  if (Property == NULL) {
+    DEBUG ((DEBUG_ERROR, "Config Id is NULL\n"));
+    return 0;
+  }
+
+  ConfigId = fdt32_to_cpu (*Property);
+
+  // Ensure upper 28-bits of config-id is set to zero.
+  ASSERT ((ConfigId >> SGI_CONFIG_MASK) == 0);
+
+  // Concatenate the value of config ID into the platform ID value with
+  // config ID occupying the upper 4 bits of platform ID.
+  PlatformId = PlatformId | (ConfigId << SGI_CONFIG_SHIFT);
+
+  return PlatformId;
 }
 
 /**
-- 
2.7.4