arm-bsp/edk2-firmware: fix N1SDP build with clang

Clang finds more bad code paths than GCC, and edk2 uses -Werror.

Pending status because the upstreamed support appears to have been
entirely rewritten.

Change-Id: I43d4e7f28f0a6acc4ecdd1514402c1b831871b5b
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm-bsp/recipes-bsp/uefi/edk2-firmware-n1sdp.inc

@@ -1,6 +1,8 @@
 EDK2_SRC_URI = "git://git.linaro.org/landing-teams/working/arm/edk2.git"
 EDK2_PLATFORMS_SRC_URI = "git://git.linaro.org/landing-teams/working/arm/edk2-platforms.git"
 
+SRC_URI += "file://initialise.patch"
+
 # TAGS and commit ID as per N1SDP-2020.03.26 release
 SRCREV_edk2           = "3ff8a6bffabad761279817252014d59b6069d68a"
 SRCREV_edk2-platforms = "d9d32e6c8b7456d21ce365486ac563b6be36c20d"

meta-arm-bsp/recipes-bsp/uefi/edk2-firmware_git.bbappend

@@ -1,3 +1,5 @@
+FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
+
 # Include machine specific configurations for UEFI EDK2
 
 MACHINE_EDK2_REQUIRE ?= ""

meta-arm-bsp/recipes-bsp/uefi/files/initialise.patch

@@ -0,0 +1,32 @@
+These variables can be returned without being set, so assign reasonable
+fallback values for the error paths.
+
+Upstream-Status: Pending
+Signed-off-by: Ross Burton <ross.burton@arm.com>
+
+From ef296251231a9a646051efbed0d81131f0876e25 Mon Sep 17 00:00:00 2001
+From: Ross Burton <ross.burton@arm.com>
+Date: Wed, 21 Oct 2020 17:29:17 +0100
+Subject: [PATCH] Add missing Status assignments
+
+---
+ Platform/ARM/Drivers/CcixDxe/CcixEnumeration.c          | 2 +-
+ Platform/ARM/N1SdpPkg/Drivers/PlatformDxe/PlatformDxe.c | 2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/Platform/ARM/Drivers/CcixDxe/CcixEnumeration.c b/Platform/ARM/Drivers/CcixDxe/CcixEnumeration.c
+index b605d9adbd..6b11a8545d 100644
+--- a/edk2-platforms/Platform/ARM/Drivers/CcixDxe/CcixEnumeration.c
++++ b/edk2-platforms/Platform/ARM/Drivers/CcixDxe/CcixEnumeration.c
+@@ -684 +684 @@ CcixAgentInit(
+-  EFI_STATUS Status;
++  EFI_STATUS Status = EFI_ABORTED;
+diff --git a/Platform/ARM/N1SdpPkg/Drivers/PlatformDxe/PlatformDxe.c b/Platform/ARM/N1SdpPkg/Drivers/PlatformDxe/PlatformDxe.c
+index c828165d07..e1f7f5e8ea 100644
+--- a/edk2-platforms/Platform/ARM/N1SdpPkg/Drivers/PlatformDxe/PlatformDxe.c
++++ b/edk2-platforms/Platform/ARM/N1SdpPkg/Drivers/PlatformDxe/PlatformDxe.c
+@@ -26 +26 @@ ArmN1SdpPkgEntryPoint (
+-  EFI_STATUS                 Status;
++  EFI_STATUS                 Status = EFI_UNSUPPORTED;
+-- 
+2.25.1