[PATCH v2 3/5] ArmVirtPkg/FdtClientDxe: take DT node 'status' properties into account

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

DT has a [pseudo-]standardized 'status' property that can be set on
any node, and which signifies that a node should be treated as
absent unless it is set to 'ok' or 'okay'. So take this into account
when iterating over nodes.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 ArmVirtPkg/FdtClientDxe/FdtClientDxe.c | 38 +++++++++++++++++---
 1 file changed, 33 insertions(+), 5 deletions(-)

diff --git a/ArmVirtPkg/FdtClientDxe/FdtClientDxe.c b/ArmVirtPkg/FdtClientDxe/FdtClientDxe.c
index fb6e0aeb9215..5bfde381ecd0 100644
--- a/ArmVirtPkg/FdtClientDxe/FdtClientDxe.c
+++ b/ArmVirtPkg/FdtClientDxe/FdtClientDxe.c
@@ -78,6 +78,33 @@ SetNodeProperty (
   return EFI_SUCCESS;
 }
 
+STATIC
+BOOLEAN
+IsNodeEnabled (
+  INT32                       Node
+  )
+{
+  CONST CHAR8   *NodeStatus;
+  INT32         Len;
+
+  //
+  // A missing status property implies 'ok' so ignore any errors that
+  // may occur here. If the status property is present, check whether
+  // it is set to 'ok' or 'okay', anything else is treated as 'disabled'.
+  //
+  NodeStatus = fdt_getprop (mDeviceTreeBase, Node, "status", &Len);
+  if (NodeStatus == NULL) {
+    return TRUE;
+  }
+  if (Len >= 5 && AsciiStrCmp (NodeStatus, "okay") == 0) {
+    return TRUE;
+  }
+  if (Len >= 3 && AsciiStrCmp (NodeStatus, "ok") == 0) {
+    return TRUE;
+  }
+  return FALSE;
+}
+
 STATIC
 EFI_STATUS
 EFIAPI
@@ -101,6 +128,10 @@ FindNextCompatibleNode (
       break;
     }
 
+    if (!IsNodeEnabled (Next)) {
+      continue;
+    }
+
     Type = fdt_getprop (mDeviceTreeBase, Next, "compatible", &Len);
     if (Type == NULL) {
       continue;
@@ -210,7 +241,6 @@ FindNextMemoryNodeReg (
 {
   INT32          Prev, Next;
   CONST CHAR8    *DeviceType;
-  CONST CHAR8    *NodeStatus;
   INT32          Len;
   EFI_STATUS     Status;
 
@@ -223,10 +253,8 @@ FindNextMemoryNodeReg (
       break;
     }
 
-    NodeStatus = fdt_getprop (mDeviceTreeBase, Next, "status", &Len);
-    if (NodeStatus != NULL && AsciiStrCmp (NodeStatus, "okay") != 0) {
-      DEBUG ((DEBUG_WARN, "%a: ignoring memory node with status \"%a\"\n",
-        __FUNCTION__, NodeStatus));
+    if (!IsNodeEnabled (Next)) {
+      DEBUG ((DEBUG_WARN, "%a: ignoring disabled memory node\n", __FUNCTION__));
       continue;
     }
 
-- 
2.17.1