MdePkg: Add UEFI2.5 Ramdisk device path definition

[mirror_edk2.git] / MdePkg / Include / Protocol / VariableWrite.h

diff --git a/MdePkg/Include/Protocol/VariableWrite.h b/MdePkg/Include/Protocol/VariableWrite.h
index cb8050eb0d942aaf8ace76a9c30b0540b52dec5f..5a4c15852dff68acc77b339b6c79c210024d616d 100644 (file)
--- a/MdePkg/Include/Protocol/VariableWrite.h
+++ b/MdePkg/Include/Protocol/VariableWrite.h
@@ -1,15 +1,27 @@
 /** @file\r
   Variable Write Architectural Protocol as defined in PI Specification VOLUME 2 DXE\r
 \r
-  This code is used to produce the UEFI 2.0 runtime variable services\r
-\r
-  The SetVariable () UEFI 2.0 services may be updated to the EFI system table and the \r
-  EFI_VARIABLE_WRITE_ARCH_PROTOCOL_GUID protocol is registered with a NULL pointer.\r
-\r
-  No CRC of the EFI system table is required, as it is done in the DXE core.\r
-\r
-  Copyright (c) 2006 - 2008, Intel Corporation                                                         \r
-  All rights reserved. This program and the accompanying materials                          \r
+  This provides the services required to set nonvolatile environment variables. \r
+  This protocol must be produced by a runtime DXE driver and may be consumed only \r
+  by the DXE Foundation.\r
+\r
+  The DXE driver that produces this protocol must be a runtime driver. This driver \r
+  may update the SetVariable() field of the UEFI Runtime Services Table.\r
+  \r
+  After the UEFI Runtime Services Table has been initialized, the driver must \r
+  install the EFI_VARIABLE_WRITE_ARCH_PROTOCOL_GUID on a new handle with a NULL \r
+  interface pointer. The installation of this protocol informs the DXE Foundation \r
+  that the write services for nonvolatile environment variables are now available \r
+  and that the DXE Foundation must update the 32-bit CRC of the UEFI Runtime Services \r
+  Table. The full complement of environment variable services are not available \r
+  until both this protocol and EFI_VARIABLE_ARCH_PROTOCOL are installed. DXE drivers \r
+  that require read-only access or read/write access to volatile environment variables\r
+  must have the EFI_VARIABLE_WRITE_ARCH_PROTOCOL in their dependency expressions.\r
+  DXE drivers that require write access to nonvolatile environment variables must \r
+  have this architectural protocol in their dependency expressions.  \r
+  \r
+  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
+  This program and the accompanying materials                          \r
   are licensed and made available under the terms and conditions of the BSD License         \r
   which accompanies this distribution.  The full text of the license may be found at        \r
   http://opensource.org/licenses/bsd-license.php                                            \r
@@ -22,9 +34,9 @@
 #ifndef __ARCH_PROTOCOL_VARIABLE_WRITE_ARCH_H__\r
 #define __ARCH_PROTOCOL_VARIABLE_WRITE_ARCH_H__\r
 \r
-//\r
-// Global ID for the Variable Write Architectural Protocol\r
-//\r
+///\r
+/// Global ID for the Variable Write Architectural Protocol\r
+///\r
 #define EFI_VARIABLE_WRITE_ARCH_PROTOCOL_GUID \\r
   { 0x6441f818, 0x6362, 0x4e44, {0xb5, 0x70, 0x7d, 0xba, 0x31, 0xdd, 0x24, 0x53 } }\r
 \r