[RFT PATCH] EmbeddedPkg/AndroidFastbootApp: remove dependency on deprecated BdsLib

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

One of the last remaining modules with a dependency on the deprecated
BdsLib implementation from ArmPkg is the Android fastboot application.

Its only dependency on BdsLib is BdsStartEfiApplication(), which is
used in the most peculiar way: the fastboot app loads the kernel image
into memory, and creates a MemoryMapped() device path for it. It then
proceeds and calls BdsStartEfiApplication(), which explicitly loads the
contents of the devicepath into memory, creating a second in-memory copy
of the kernel image, after which it invokes gBS->LoadImage() with a
buffer address and size (while it is perfectly capable of loading from
a devicepath directly)

Since we know the device path is fully qualified and connected, and does
not require any of the additional processing that BdsStartEfiApplication()
does when dereferencing a device path, we should be able to pass this
devicepath into LoadImage() directly.

So create a simplified local clone of BdsStartEfiApplication(), and drop
the dependency on BdsLib.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 EmbeddedPkg/Application/AndroidFastboot/AndroidFastbootApp.inf   |  2 +-
 EmbeddedPkg/Application/AndroidFastboot/Arm/BootAndroidBootImg.c | 57 +++++++++++++++++++-
 2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/EmbeddedPkg/Application/AndroidFastboot/AndroidFastbootApp.inf b/EmbeddedPkg/Application/AndroidFastboot/AndroidFastbootApp.inf
index 3e115171ce01..8d2b23c6f8b8 100644
--- a/EmbeddedPkg/Application/AndroidFastboot/AndroidFastbootApp.inf
+++ b/EmbeddedPkg/Application/AndroidFastboot/AndroidFastbootApp.inf
@@ -30,7 +30,6 @@ [Sources.ARM, Sources.AARCH64]
 [LibraryClasses]
   BaseLib
   BaseMemoryLib
-  BdsLib
   DebugLib
   DevicePathLib
   DxeServicesTableLib
@@ -45,6 +44,7 @@ [LibraryClasses]
 [Protocols]
   gAndroidFastbootTransportProtocolGuid
   gAndroidFastbootPlatformProtocolGuid
+  gEfiLoadedImageProtocolGuid
   gEfiSimpleTextOutProtocolGuid
   gEfiSimpleTextInProtocolGuid
 
diff --git a/EmbeddedPkg/Application/AndroidFastboot/Arm/BootAndroidBootImg.c b/EmbeddedPkg/Application/AndroidFastboot/Arm/BootAndroidBootImg.c
index 46a7ceb3a41c..f446cce2855a 100644
--- a/EmbeddedPkg/Application/AndroidFastboot/Arm/BootAndroidBootImg.c
+++ b/EmbeddedPkg/Application/AndroidFastboot/Arm/BootAndroidBootImg.c
@@ -15,6 +15,7 @@
 #include "AndroidFastbootApp.h"
 
 #include <Protocol/DevicePath.h>
+#include <Protocol/LoadedImage.h>
 
 #include <Library/BdsLib.h>
 #include <Library/DevicePathLib.h>
@@ -50,6 +51,60 @@ STATIC CONST MEMORY_DEVICE_PATH MemoryDevicePathTemplate =
   } // End
 };
 
+
+/**
+  Start an EFI Application from a Device Path
+
+  @param  ParentImageHandle     Handle of the calling image
+  @param  DevicePath            Location of the EFI Application
+
+  @retval EFI_SUCCESS           All drivers have been connected
+  @retval EFI_NOT_FOUND         The Linux kernel Device Path has not been found
+  @retval EFI_OUT_OF_RESOURCES  There is not enough resource memory to store the matching results.
+
+**/
+STATIC
+EFI_STATUS
+StartEfiApplication (
+  IN EFI_HANDLE                  ParentImageHandle,
+  IN EFI_DEVICE_PATH_PROTOCOL    *DevicePath,
+  IN UINTN                       LoadOptionsSize,
+  IN VOID*                       LoadOptions
+  )
+{
+  EFI_STATUS                   Status;
+  EFI_HANDLE                   ImageHandle;
+  EFI_LOADED_IMAGE_PROTOCOL*   LoadedImage;
+
+  // Load the image from the device path with Boot Services function
+  Status = gBS->LoadImage (TRUE, ParentImageHandle, DevicePath, NULL, 0,
+                  &ImageHandle);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  // Passed LoadOptions to the EFI Application
+  if (LoadOptionsSize != 0) {
+    Status = gBS->HandleProtocol (ImageHandle, &gEfiLoadedImageProtocolGuid,
+                    (VOID **) &LoadedImage);
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+
+    LoadedImage->LoadOptionsSize  = LoadOptionsSize;
+    LoadedImage->LoadOptions      = LoadOptions;
+  }
+
+  // Before calling the image, enable the Watchdog Timer for  the 5 Minute period
+  gBS->SetWatchdogTimer (5 * 60, 0x0000, 0x00, NULL);
+  // Start the image
+  Status = gBS->StartImage (ImageHandle, NULL, NULL);
+  // Clear the Watchdog Timer after the image returns
+  gBS->SetWatchdogTimer (0x0000, 0x0000, 0x0000, NULL);
+
+  return Status;
+}
+
 EFI_STATUS
 BootAndroidBootImg (
   IN UINTN    BufferSize,
@@ -100,7 +155,7 @@ BootAndroidBootImg (
     LoadOptions = NewLoadOptions;
   }
 
-  Status = BdsStartEfiApplication (gImageHandle,
+  Status = StartEfiApplication (gImageHandle,
              (EFI_DEVICE_PATH_PROTOCOL *) &KernelDevicePath,
              StrSize (LoadOptions),
              LoadOptions);
-- 
2.9.3