Add comment for device path protocol.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@6175 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 23 insertions, 3 deletions

diff --git a/MdePkg/Include/Protocol/DevicePath.h b/MdePkg/Include/Protocol/DevicePath.h
index 1286372f03..2103452909 100644
--- a/MdePkg/Include/Protocol/DevicePath.h
+++ b/MdePkg/Include/Protocol/DevicePath.h
@@ -40,10 +40,30 @@
 

 #pragma pack(1)

 

+/**

+  This protocol can be used on any device handle to obtain generic path/location 

+  information concerning the physical device or logical device. If the handle does 

+  not logically map to a physical device, the handle may not necessarily support 

+  the device path protocol. The device path describes the location of the device 

+  the handle is for. The size of the Device Path can be determined from the structures 

+  that make up the Device Path.

+**/

 typedef struct {

-  UINT8 Type;

-  UINT8 SubType;

-  UINT8 Length[2];

+  UINT8 Type;       ///< 0x01 - Hardware Device Path

+                    ///< 0x02 – ACPI Device Path

+                    ///< 0x03 – Messaging Device Path

+                    ///< 0x04 – Media Device Path

+                    ///< 0x05 – BIOS Boot Specification Device Path

+                    ///< 0x7F – End of Hardware Device Path

+                    

+  UINT8 SubType;    ///< Varies by Type

+                    ///< 0xFF – End Entire Device Path, or

+                    ///< 0x01 – End This Instance of a Device Path and start a new

+                    ///< Device Path

+                    

+  UINT8 Length[2];  ///< Specific Device Path data. Type and Sub-Type define

+                    ///< type of data. Size of data is included in Length.

+                    

 } EFI_DEVICE_PATH_PROTOCOL;

 

 ///