MdeModulePkg/Universal/PlatformDriverOverride/PlatformDriOverrideDxe/PlatformDriOverride.c

   1 /** @file
   2
   3 Copyright (c) 2007, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12 Module Name:
  13
  14     PlatformDriOverride.c
  15
  16 Abstract:
  17
  18
  19 **/
  20
  21
  22 #include "PlatformDriOverride.h"
  23
  24 EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL gPlatformDriverOverride = {
  25   GetDriver,
  26   GetDriverPath,
  27   DriverLoaded
  28 };
  29
  30 LIST_ENTRY      mMappingDataBase = INITIALIZE_LIST_HEAD_VARIABLE (mMappingDataBase);
  31 BOOLEAN         mEnvironmentVariableRead = FALSE;
  32 EFI_HANDLE      mCallerImageHandle;
  33
  34
  35 EFI_STATUS
  36 EFIAPI
  37 PlatformDriverOverrideEntry (
  38   IN EFI_HANDLE        ImageHandle,
  39   IN EFI_SYSTEM_TABLE  *SystemTable
  40   )
  41 /*++
  42
  43 Routine Description:
  44    Platform Driver Override driver entry point, install the Platform Driver Override Protocol
  45
  46 Arguments:
  47   (Standard EFI Image entry - EFI_IMAGE_ENTRY_POINT)
  48
  49 Returns:
  50   EFI_STATUS
  51
  52 --*/
  53 {
  54   mEnvironmentVariableRead = FALSE;
  55   mCallerImageHandle = ImageHandle;
  56   InitializeListHead (&mMappingDataBase);
  57   return InstallPlatformDriverOverrideProtocol (&gPlatformDriverOverride);
  58 }
  59
  60
  61 /**
  62   Retrieves the image handle of the platform override driver for a controller in the system.
  63
  64   @param  This                   A pointer to the
  65                                  EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL instance.
  66   @param  ControllerHandle       The device handle of the controller to check if a
  67                                  driver override exists.
  68   @param  DriverImageHandle      On input, a pointer to the previous driver image
  69                                  handle returned by GetDriver().  On output, a
  70                                  pointer to the next driver image handle. Passing
  71                                  in a NULL,  will return the first driver image
  72                                  handle for ControllerHandle.
  73
  74   @retval EFI_SUCCESS            The driver override for ControllerHandle was
  75                                  returned in DriverImageHandle.
  76   @retval EFI_NOT_FOUND          A driver override for ControllerHandle was not
  77                                  found.
  78   @retval EFI_INVALID_PARAMETER  The handle specified by ControllerHandle is not a
  79                                  valid handle. DriverImageHandle is not a handle
  80                                  that was returned on a previous  call to
  81                                  GetDriver().
  82
  83 **/
  84 EFI_STATUS
  85 EFIAPI
  86 GetDriver (
  87   IN EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL              * This,
  88   IN     EFI_HANDLE                                     ControllerHandle,
  89   IN OUT EFI_HANDLE                                     * DriverImageHandle
  90   )
  91 {
  92   EFI_STATUS  Status;
  93   //
  94   // Check that ControllerHandle is a valid handle
  95   //
  96   if (ControllerHandle == NULL) {
  97     return EFI_INVALID_PARAMETER;
  98   }
  99
 100   //
 101   // Read the environment variable(s) that contain the override mappings from Controller Device Path to
 102   // a set of Driver Device Paths, and  initialize in memory database of the overrides that map Controller
 103   // Device Paths to an ordered set of Driver Device Paths and Driver Handles. This action is only performed
 104   // once and finished in first call.
 105   //
 106   if (!mEnvironmentVariableRead) {
 107     mEnvironmentVariableRead = TRUE;
 108
 109     Status = InitOverridesMapping (&mMappingDataBase);
 110     if (Status == EFI_NOT_FOUND) {
 111       InitializeListHead (&mMappingDataBase);
 112       return EFI_NOT_FOUND;
 113     } else if (Status == EFI_VOLUME_CORRUPTED){
 114       DEBUG ((DEBUG_ERROR, "Platform Driver Override Variable is corrupt\n"));
 115       //
 116       // The environment variable(s) that contain the override mappings from Controller Device Path to
 117       //  a set of Driver Device Paths is corrupted,  platform code can use LibDeleteOverridesVariables to
 118       //  delete all orverride variables as a policy. Here can be IBV/OEM customized.
 119       //
 120
 121       //LibDeleteOverridesVariables();
 122       InitializeListHead (&mMappingDataBase);
 123       return EFI_NOT_FOUND;
 124     } else if (EFI_ERROR (Status)){
 125       InitializeListHead (&mMappingDataBase);
 126       return EFI_NOT_FOUND;
 127     }
 128   }
 129   //
 130   // if the environment variable does not exist or the variable appears to be corrupt, just return not found
 131   //
 132   if (IsListEmpty (&mMappingDataBase)) {
 133     return EFI_NOT_FOUND;
 134   }
 135
 136   return GetDriverFromMapping (
 137             This,
 138             ControllerHandle,
 139             DriverImageHandle,
 140             &mMappingDataBase,
 141             mCallerImageHandle
 142             );
 143
 144 }
 145
 146
 147 /**
 148   For the use of the ControllerHandle parameter in the GetDriverPath() and DriverLoaded() APIs
 149   makes those APIs very difficult to use, so not support.
 150
 151
 152
 153 **/
 154 EFI_STATUS
 155 EFIAPI
 156 GetDriverPath (
 157   IN EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL              * This,
 158   IN     EFI_HANDLE                                     ControllerHandle,
 159   IN OUT EFI_DEVICE_PATH_PROTOCOL                       **DriverImagePath
 160   )
 161 {
 162   return EFI_UNSUPPORTED;
 163 }
 164
 165
 166 /**
 167   For the use of the ControllerHandle parameter in the GetDriverPath() and DriverLoaded() APIs
 168   makes those APIs very difficult to use, so not support.
 169
 170
 171
 172 **/
 173 EFI_STATUS
 174 EFIAPI
 175 DriverLoaded (
 176   IN EFI_PLATFORM_DRIVER_OVERRIDE_PROTOCOL          * This,
 177   IN EFI_HANDLE                                     ControllerHandle,
 178   IN EFI_DEVICE_PATH_PROTOCOL                       * DriverImagePath,
 179   IN EFI_HANDLE                                     DriverImageHandle
 180   )
 181 {
 182   return EFI_UNSUPPORTED;
 183 }