[PATCH 3/5] OvmfPkg/IndustryStandard: add QemuFwCfgDma.h

[Laszlo Ersek <lersek@redhat.com>]

Add the type and macro definitions related to QEMU's DMA-like fw_cfg
access method in a dedicated header file.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 OvmfPkg/Include/IndustryStandard/QemuFwCfgDma.h | 50 ++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/OvmfPkg/Include/IndustryStandard/QemuFwCfgDma.h b/OvmfPkg/Include/IndustryStandard/QemuFwCfgDma.h
new file mode 100644
index 000000000000..37a5804adb05
--- /dev/null
+++ b/OvmfPkg/Include/IndustryStandard/QemuFwCfgDma.h
@@ -0,0 +1,50 @@
+/** @file
+  Macro and type definitions related to QEMU's DMA-like fw_cfg access method,
+  based on "docs/specs/fw_cfg.txt" in the QEMU tree.
+
+  Copyright (C) 2016, Red Hat, Inc.
+
+  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.
+**/
+
+
+#ifndef __FW_CFG_DMA__
+#define __FW_CFG_DMA__
+
+#include <Base.h>
+
+//
+// If the following bit is set in the UINT32 fw_cfg revision / feature bitmap
+// -- read from key 0x0001 with the basic IO Port or MMIO method --, then the
+// DMA interface is available.
+//
+#define FW_CFG_F_DMA BIT1
+
+//
+// Communication structure for the DMA access method. All fields are encoded in
+// big endian.
+//
+#pragma pack (1)
+typedef struct {
+  UINT32 Control;
+  UINT32 Length;
+  UINT64 Address;
+} FW_CFG_DMA_ACCESS;
+#pragma pack ()
+
+//
+// Macros for the FW_CFG_DMA_ACCESS.Control bitmap (in native encoding).
+//
+#define FW_CFG_DMA_CTL_ERROR  BIT0
+#define FW_CFG_DMA_CTL_READ   BIT1
+#define FW_CFG_DMA_CTL_SKIP   BIT2
+#define FW_CFG_DMA_CTL_SELECT BIT3
+#define FW_CFG_DMA_CTL_WRITE  BIT4
+
+#endif
-- 
2.9.2