[edk2-platforms: PATCH 1/1] Platform/Rpi3: Add compatible property to the "usb" Device Tree node

["Pete Batard" <pete@akeo.ie>]

Some Linux kernels (e.g. Debian) require "bcm,bcm2835-usb" to be present in
the list of compatible properties for the "usb" node, else they are unable
to handle some USB devices.

This patch ensures that the compatible property is added if not present.

Signed-off-by: Pete Batard <pete@akeo.ie>
---
 Platform/RaspberryPi/RPi3/Drivers/FdtDxe/FdtDxe.c | 74 ++++++++++++++++++++
 1 file changed, 74 insertions(+)

diff --git a/Platform/RaspberryPi/RPi3/Drivers/FdtDxe/FdtDxe.c b/Platform/RaspberryPi/RPi3/Drivers/FdtDxe/FdtDxe.c
index 45ffe2e394a2..399a48430457 100644
--- a/Platform/RaspberryPi/RPi3/Drivers/FdtDxe/FdtDxe.c
+++ b/Platform/RaspberryPi/RPi3/Drivers/FdtDxe/FdtDxe.c
@@ -135,6 +135,75 @@ UpdateMacAddress (
   return EFI_SUCCESS;
 }
 
+//
+// Add "bcm2835-usb" to the USB compatible property list, if not present.
+// Required because some Linux kernels can't handle USB devices otherwise.
+//
+STATIC
+EFI_STATUS
+AddUsbCompatibleProperty (
+  VOID
+  )
+{
+  CONST CHAR8   Prop[]    = "brcm,bcm2708-usb";
+  CONST CHAR8   NewProp[] = "brcm,bcm2835-usb";
+  CONST CHAR8   *List;
+  CHAR8         *NewList;
+  INT32         ListSize;
+  INTN          Node;
+  INTN          Retval;
+
+  // Locate the node that the 'usb' alias refers to
+  Node = fdt_path_offset (mFdtImage, "usb");
+  if (Node < 0) {
+    DEBUG ((DEBUG_ERROR, "%a: failed to locate 'usb' alias\n", __FUNCTION__));
+    return EFI_NOT_FOUND;
+  }
+
+  // Get the property list. This is a list of NUL terminated strings.
+  List = fdt_getprop (mFdtImage, Node, "compatible", &ListSize);
+  if (List == NULL) {
+    DEBUG ((DEBUG_ERROR, "%a: failed to locate properties\n", __FUNCTION__));
+    return EFI_NOT_FOUND;
+  }
+
+  // Check if the compatible value we plan to add is already present
+  if (fdt_stringlist_contains (List, ListSize, NewProp)) {
+    DEBUG ((DEBUG_INFO, "%a: property '%a' is already set.\n",
+      __FUNCTION__, NewProp));
+    return EFI_SUCCESS;
+  }
+
+  // Make sure the compatible device is what we expect
+  if (!fdt_stringlist_contains (List, ListSize, Prop)) {
+    DEBUG ((DEBUG_ERROR, "%a: property '%a' is missing!\n",
+      __FUNCTION__, Prop));
+    return EFI_NOT_FOUND;
+  }
+
+  // Add the new NUL terminated entry to our list
+  DEBUG ((DEBUG_INFO, "%a: adding '%a' to the properties\n",
+    __FUNCTION__, NewProp));
+
+  NewList = AllocatePool (ListSize + sizeof (NewProp));
+  if (NewList == NULL) {
+    DEBUG ((DEBUG_ERROR, "%a: failed to allocate memory\n", __FUNCTION__));
+    return EFI_OUT_OF_RESOURCES;;
+  }
+  CopyMem (NewList, List, ListSize);
+  CopyMem (&NewList[ListSize], NewProp, sizeof (NewProp));
+
+  Retval = fdt_setprop (mFdtImage, Node, "compatible", NewList,
+             ListSize + sizeof (NewProp));
+  if (Retval != 0) {
+    DEBUG ((DEBUG_ERROR, "%a: failed to update properties (%d)\n",
+      __FUNCTION__, Retval));
+    return EFI_NOT_FOUND;
+  }
+
+  return EFI_SUCCESS;
+}
+
 STATIC
 EFI_STATUS
 CleanMemoryNodes (
@@ -486,6 +555,11 @@ FdtDxeInitialize (
     Print (L"Failed to update MAC address: %r\n", Status);
   }
 
+  Status = AddUsbCompatibleProperty ();
+  if (EFI_ERROR (Status)) {
+    Print (L"Failed to update USB compatible properties: %r\n", Status);
+  }
+
   if (Internal) {
     /*
      * A GPU-provided DTB already has the full command line.
-- 
2.21.0.windows.1