QemuFwCfgLib: Add QemuFwCfgWriteBytes() function

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14109 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c

@@ -1,6 +1,6 @@
 /** @file
 
-  Copyright (c) 2011 - 2012, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
 
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
@@ -50,6 +50,32 @@ IoReadFifo8 (
   OUT     VOID                      *Buffer
   );
 
+/**
+  Writes an 8-bit I/O port fifo from a block of memory.
+
+  Writes the 8-bit I/O fifo port specified by Port.
+
+  The port is written Count times, and the data are obtained
+  from the provided Buffer.
+
+  This function must guarantee that all I/O read and write operations are
+  serialized.
+
+  If 8-bit I/O port operations are not supported, then ASSERT().
+
+  @param  Port    The I/O port to read.
+  @param  Count   The number of times to read I/O port.
+  @param  Buffer  The buffer to store the read data into.
+
+**/
+VOID
+EFIAPI
+IoWriteFifo8 (
+  IN      UINTN                     Port,
+  IN      UINTN                     Count,
+  OUT     VOID                      *Buffer
+  );
+
 
 /**
   Returns a boolean indicating if the firmware configuration interface
@@ -132,6 +158,29 @@ QemuFwCfgReadBytes (
   }
 }
 
+/**
+  Write firmware configuration bytes from a buffer
+
+  If called multiple times, then the data written will
+  continue at the offset of the firmware configuration
+  item where the previous write ended.
+
+  @param[in] Size - Size in bytes to write
+  @param[in] Buffer - Buffer to read data from
+
+**/
+VOID
+EFIAPI
+QemuFwCfgWriteBytes (
+  IN UINTN                  Size,
+  IN VOID                   *Buffer
+  )
+{
+  if (mQemuFwCfgSupported) {
+    IoWriteFifo8 (0x511, Size, Buffer);
+  }
+}
+
 
 /**
   Reads a UINT8 firmware configuration value