[edk2-platforms][PATCH 2/3] Platform/RPi: Add PlatformPcdLib to set the Genet MAC address

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

The Genet driver stub used by the Raspberry Pi 4 platform is
designed to set the MAC address according to a PCD.

To be able to set that PCD at runtime, by using the Raspberry
Pi firmware interface, that has a dedicated call to retrieve
the MAC address, and satisfy driver dependencies in a generic
manner, we create a new PlatformPcdLib that can be referenced
by the Genet driver, to set the MAC PCD before use there.

While it is currently only tailored around MAC PCD population
for Genet, we do expect this PCD library to be extended in the
future, to provide additional PCD facilities for other drivers.

Signed-off-by: Pete Batard <pete@akeo.ie>
---
 Platform/RaspberryPi/Library/PlatformPcdLib/PlatformPcdLib.c   | 61 ++++++++++++++++++++
 Platform/RaspberryPi/Library/PlatformPcdLib/PlatformPcdLib.inf | 44 ++++++++++++++
 2 files changed, 105 insertions(+)

diff --git a/Platform/RaspberryPi/Library/PlatformPcdLib/PlatformPcdLib.c b/Platform/RaspberryPi/Library/PlatformPcdLib/PlatformPcdLib.c
new file mode 100644
index 000000000000..78f3679e2e48
--- /dev/null
+++ b/Platform/RaspberryPi/Library/PlatformPcdLib/PlatformPcdLib.c
@@ -0,0 +1,61 @@
+/** @file
+ *
+ *  Copyright (c) 2020, Pete Batard <pete@akeo.ie>
+ *
+ *  SPDX-License-Identifier: BSD-2-Clause-Patent
+ *
+ **/
+
+#include <Library/DebugLib.h>
+#include <Library/PcdLib.h>
+#include <Library/PrintLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+#include <Protocol/RpiFirmware.h>
+
+EFI_STATUS
+EFIAPI
+PlatformPcdLibConstructor (
+  IN EFI_HANDLE ImageHandle,
+  IN EFI_SYSTEM_TABLE *SystemTable
+  )
+{
+
+  //
+  // If Genet is in use and a MAC address PCD has not been set, do it here.
+  //
+#if (FixedPcdGet64 (PcdBcmGenetRegistersAddress) != 0)
+  EFI_STATUS                       Status;
+  UINT64                           MacAddr;
+  RASPBERRY_PI_FIRMWARE_PROTOCOL   *mFwProtocol;
+
+  if (PcdGet64 (PcdBcmGenetMacAddress) == 0) {
+    Status = gBS->LocateProtocol (&gRaspberryPiFirmwareProtocolGuid, NULL,
+                    (VOID**)&mFwProtocol);
+    ASSERT_EFI_ERROR(Status);
+
+    //
+    // Get the MAC address from the firmware
+    //
+    Status = mFwProtocol->GetMacAddress ((UINT8*) &MacAddr);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_WARN, "%a: failed to retrieve MAC address\n", __FUNCTION__));
+    } else {
+      PcdSet64 (PcdBcmGenetMacAddress, MacAddr);
+    }
+  }
+#endif
+
+  return EFI_SUCCESS;
+}
+
+EFI_STATUS
+EFIAPI
+PlatformPcdLibDestructor (
+  IN EFI_HANDLE ImageHandle,
+  IN EFI_SYSTEM_TABLE *SystemTable
+  )
+{
+  return EFI_SUCCESS;
+}
diff --git a/Platform/RaspberryPi/Library/PlatformPcdLib/PlatformPcdLib.inf b/Platform/RaspberryPi/Library/PlatformPcdLib/PlatformPcdLib.inf
new file mode 100644
index 000000000000..a564ddfbb2a3
--- /dev/null
+++ b/Platform/RaspberryPi/Library/PlatformPcdLib/PlatformPcdLib.inf
@@ -0,0 +1,44 @@
+#/** @file
+#
+#  Copyright (c) 2020, Pete Batard <pete@akeo.ie>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#**/
+
+[Defines]
+  INF_VERSION                    = 0x0001001A
+  BASE_NAME                      = PlatformPcdLib
+  FILE_GUID                      = 3B8409D7-D3C7-4006-823B-BFB184435363
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = NULL|DXE_DRIVER UEFI_APPLICATION
+  CONSTRUCTOR                    = PlatformPcdLibConstructor
+  DESTRUCTOR                     = PlatformPcdLibDestructor
+
+[Sources]
+  PlatformPcdLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  Platform/RaspberryPi/RaspberryPi.dec
+  Silicon/Broadcom/Drivers/Net/BcmNet.dec
+
+[LibraryClasses]
+  UefiLib
+  DebugLib
+  PrintLib
+
+[Protocols]
+  gRaspberryPiFirmwareProtocolGuid              ## CONSUMES
+
+[Pcd]
+  gBcmNetTokenSpaceGuid.PcdBcmGenetMacAddress   ## SOMETIMES_PRODUCES
+
+[FixedPcd]
+  gBcmNetTokenSpaceGuid.PcdBcmGenetRegistersAddress
+
+[Depex]
+  gPcdProtocolGuid AND gRaspberryPiFirmwareProtocolGuid
+
-- 
2.21.0.windows.1