OvmfPkg: QemuFwCfgLib: introduce InternalQemuFwCfgIsAvailable()

This internal function allows separation of library-internal and
for-clients external availability of fw_cfg.

The interface contract of QemuFwCfgIsAvailable() is changed so that now it
may modify fw_cfg state. All current users are compliant with the new
contract.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15044 6f19259b-4bc3-4df7-8a09-765794883524

2 files changed, 47 insertions, 4 deletions

diff --git a/OvmfPkg/Include/Library/QemuFwCfgLib.h b/OvmfPkg/Include/Library/QemuFwCfgLib.h
index 9d023777c..2519fc297 100644
--- a/OvmfPkg/Include/Library/QemuFwCfgLib.h
+++ b/OvmfPkg/Include/Library/QemuFwCfgLib.h
@@ -2,6 +2,8 @@
   QEMU/KVM Firmware Configuration access

 

   Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>

+  Copyright (C) 2013, 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

@@ -56,6 +58,8 @@ typedef enum {
   Returns a boolean indicating if the firmware configuration interface

   is available or not.

 

+  This function may change fw_cfg state.

+

   @retval    TRUE   The interface is available

   @retval    FALSE  The interface is not available

 

@@ -193,5 +197,22 @@ QemuFwCfgFindFile (
   OUT  FIRMWARE_CONFIG_ITEM  *Item,

   OUT  UINTN                 *Size

   );

+

+

+/**

+  Returns a boolean indicating if the firmware configuration interface is

+  available for library-internal purposes.

+

+  This function never changes fw_cfg state.

+

+  @retval    TRUE   The interface is available internally.

+  @retval    FALSE  The interface is not available internally.

+**/

+BOOLEAN

+EFIAPI

+InternalQemuFwCfgIsAvailable (

+  VOID

+  );

+

 #endif

 

diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
index 7e5ea00bf..985b383c2 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
@@ -1,6 +1,7 @@
 /** @file

 

   Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>

+  Copyright (C) 2013, Red Hat, Inc.

 

   This program and the accompanying materials

   are licensed and made available under the terms and conditions of the BSD License

@@ -81,6 +82,8 @@ IoWriteFifo8 (
   Returns a boolean indicating if the firmware configuration interface

   is available or not.

 

+  This function may change fw_cfg state.

+

   @retval    TRUE   The interface is available

   @retval    FALSE  The interface is not available

 

@@ -91,7 +94,7 @@ QemuFwCfgIsAvailable (
   VOID

   )

 {

-  return mQemuFwCfgSupported;

+  return InternalQemuFwCfgIsAvailable ();

 }

 

 

@@ -151,7 +154,7 @@ QemuFwCfgReadBytes (
   IN VOID                   *Buffer

   )

 {

-  if (mQemuFwCfgSupported) {

+  if (InternalQemuFwCfgIsAvailable ()) {

     InternalQemuFwCfgReadBytes (Size, Buffer);

   } else {

     ZeroMem (Buffer, Size);

@@ -176,7 +179,7 @@ QemuFwCfgWriteBytes (
   IN VOID                   *Buffer

   )

 {

-  if (mQemuFwCfgSupported) {

+  if (InternalQemuFwCfgIsAvailable ()) {

     IoWriteFifo8 (0x511, Size, Buffer);

   }

 }

@@ -319,7 +322,7 @@ QemuFwCfgFindFile (
   UINT32 Count;

   UINT32 Idx;

 

-  if (!mQemuFwCfgSupported) {

+  if (!InternalQemuFwCfgIsAvailable ()) {

     return RETURN_UNSUPPORTED;

   }

 

@@ -346,3 +349,22 @@ QemuFwCfgFindFile (
 

   return RETURN_NOT_FOUND;

 }

+

+

+/**

+  Returns a boolean indicating if the firmware configuration interface is

+  available for library-internal purposes.

+

+  This function never changes fw_cfg state.

+

+  @retval    TRUE   The interface is available internally.

+  @retval    FALSE  The interface is not available internally.

+**/

+BOOLEAN

+EFIAPI

+InternalQemuFwCfgIsAvailable (

+  VOID

+  )

+{

+  return mQemuFwCfgSupported;

+}