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/** @file
Copyright (c) 2007, Intel Corporation
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
Module Name:
PlatformDriOverride.c
Abstract:
**/
#include "PlatformDriOverride.h"
EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL gPlatformDriverOverride = {
GetDriver,
GetDriverPath,
DriverLoaded
};
STATIC LIST_ENTRY mMappingDataBase = INITIALIZE_LIST_HEAD_VARIABLE (mMappingDataBase);
STATIC BOOLEAN mEnvironmentVariableRead = FALSE;
STATIC EFI_HANDLE mCallerImageHandle;
EFI_STATUS
EFIAPI
PlatformDriverOverrideEntry (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
/*++
Routine Description:
Platform Driver Override driver entry point, install the Platform Driver Override Protocol
Arguments:
(Standard EFI Image entry - EFI_IMAGE_ENTRY_POINT)
Returns:
EFI_STATUS
--*/
{
mEnvironmentVariableRead = FALSE;
mCallerImageHandle = ImageHandle;
InitializeListHead (&mMappingDataBase);
return InstallPlatformDriverOverrideProtocol (&gPlatformDriverOverride);
}
/**
Retrieves the image handle of the platform override driver for a controller in the system.
@param This A pointer to the
EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL instance.
@param ControllerHandle The device handle of the controller to check if a
driver override exists.
@param DriverImageHandle On input, a pointer to the previous driver image
handle returned by GetDriver(). On output, a
pointer to the next driver image handle. Passing
in a NULL, will return the first driver image
handle for ControllerHandle.
@retval EFI_SUCCESS The driver override for ControllerHandle was
returned in DriverImageHandle.
@retval EFI_NOT_FOUND A driver override for ControllerHandle was not
found.
@retval EFI_INVALID_PARAMETER The handle specified by ControllerHandle is not a
valid handle. DriverImageHandle is not a handle
that was returned on a previous call to
GetDriver().
**/
STATIC
EFI_STATUS
EFIAPI
GetDriver (
IN EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL * This,
IN EFI_HANDLE ControllerHandle,
IN OUT EFI_HANDLE * DriverImageHandle
)
{
EFI_STATUS Status;
//
// Check that ControllerHandle is a valid handle
//
if (ControllerHandle == NULL) {
return EFI_INVALID_PARAMETER;
}
//
// Read the environment variable(s) that contain the override mappings from Controller Device Path to
// a set of Driver Device Paths, and initialize in memory database of the overrides that map Controller
// Device Paths to an ordered set of Driver Device Paths and Driver Handles. This action is only performed
// once and finished in first call.
//
if (!mEnvironmentVariableRead) {
mEnvironmentVariableRead = TRUE;
Status = InitOverridesMapping (&mMappingDataBase);
if (Status == EFI_NOT_FOUND) {
InitializeListHead (&mMappingDataBase);
return EFI_NOT_FOUND;
} else if (Status == EFI_VOLUME_CORRUPTED){
DEBUG ((DEBUG_ERROR, "Platform Driver Override Variable is corrupt\n"));
//
// The environment variable(s) that contain the override mappings from Controller Device Path to
// a set of Driver Device Paths is corrupted, platform code can use LibDeleteOverridesVariables to
// delete all orverride variables as a policy. Here can be IBV/OEM customized.
//
//LibDeleteOverridesVariables();
InitializeListHead (&mMappingDataBase);
return EFI_NOT_FOUND;
} else if (EFI_ERROR (Status)){
InitializeListHead (&mMappingDataBase);
return EFI_NOT_FOUND;
}
}
//
// if the environment variable does not exist or the variable appears to be corrupt, just return not found
//
if (IsListEmpty (&mMappingDataBase)) {
return EFI_NOT_FOUND;
}
return GetDriverFromMapping (
This,
ControllerHandle,
DriverImageHandle,
&mMappingDataBase,
mCallerImageHandle
);
}
/**
For the use of the ControllerHandle parameter in the GetDriverPath() and DriverLoaded() APIs
makes those APIs very difficult to use, so not support.
**/
STATIC
EFI_STATUS
EFIAPI
GetDriverPath (
IN EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL * This,
IN EFI_HANDLE ControllerHandle,
IN OUT EFI_DEVICE_PATH_PROTOCOL **DriverImagePath
)
{
return EFI_UNSUPPORTED;
}
/**
For the use of the ControllerHandle parameter in the GetDriverPath() and DriverLoaded() APIs
makes those APIs very difficult to use, so not support.
**/
STATIC
EFI_STATUS
EFIAPI
DriverLoaded (
IN EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL * This,
IN EFI_HANDLE ControllerHandle,
IN EFI_DEVICE_PATH_PROTOCOL * DriverImagePath,
IN EFI_HANDLE DriverImageHandle
)
{
return EFI_UNSUPPORTED;
}
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