Refine the comments for BiosVideo thunk driver.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@7738 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 51 insertions, 46 deletions

diff --git a/DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c b/DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c
index 1f39066b2e..b8603426c6 100644
--- a/DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c
+++ b/DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c
@@ -1,13 +1,29 @@
+/** @file

+  Provide legacy thunk interface for accessing Bios Video Rom.

+  

+Copyright (c) 2006 - 2007, Intel Corporation                                                         

+All rights reserved. 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.             

+

+**/

 

 #include "BiosVideo.h"

 

 #define EFI_CPU_EFLAGS_IF 0x200

 

-THUNK_CONTEXT               mThunkContext;

-

+/**

+  Initialize legacy environment for BIOS INI caller.

+  

+  @param ThunkContext   the instance pointer of THUNK_CONTEXT

+**/

 VOID

 InitializeBiosIntCaller (

-  IN  BIOS_VIDEO_DEV                 *BiosDev

+  THUNK_CONTEXT     *ThunkContext

   )

 {

   EFI_STATUS            Status;

@@ -29,32 +45,27 @@ InitializeBiosIntCaller (
                   );

   ASSERT_EFI_ERROR (Status);

   

-  mThunkContext.RealModeBuffer     = (VOID*)(UINTN)LegacyRegionBase;

-  mThunkContext.RealModeBufferSize = EFI_PAGES_TO_SIZE (RealModeBufferSize);

-  mThunkContext.ThunkAttributes    = 3;

-  AsmPrepareThunk16(&mThunkContext);

+  ThunkContext->RealModeBuffer     = (VOID*)(UINTN)LegacyRegionBase;

+  ThunkContext->RealModeBufferSize = EFI_PAGES_TO_SIZE (RealModeBufferSize);

+  ThunkContext->ThunkAttributes    = 3;

+  AsmPrepareThunk16(ThunkContext);

   

 }

 

+/**

+   Initialize interrupt redirection code and entries, because

+   IDT Vectors 0x68-0x6f must be redirected to IDT Vectors 0x08-0x0f.

+   Or the interrupt will lost when we do thunk.

+   NOTE: We do not reset 8259 vector base, because it will cause pending

+   interrupt lost.

+   

+   @param Legacy8259  Instance pointer for EFI_LEGACY_8259_PROTOCOL.

+   

+**/

 VOID

 InitializeInterruptRedirection (

-  IN  BIOS_VIDEO_DEV                 *BiosDev

+  IN  EFI_LEGACY_8259_PROTOCOL  *Legacy8259

   )

-/*++

-

-  Routine Description:

-    Initialize interrupt redirection code and entries, because

-    IDT Vectors 0x68-0x6f must be redirected to IDT Vectors 0x08-0x0f.

-    Or the interrupt will lost when we do thunk.

-    NOTE: We do not reset 8259 vector base, because it will cause pending

-    interrupt lost.

-

-  Arguments:

-    NONE

-

-  Returns:

-    NONE

---*/

 {

   EFI_STATUS            Status;

   EFI_PHYSICAL_ADDRESS  LegacyRegionBase;

@@ -94,7 +105,7 @@ InitializeInterruptRedirection (
   //

   // Get VectorBase, it should be 0x68

   //

-  Status = BiosDev->Legacy8259->GetVector (BiosDev->Legacy8259, Efi8259Irq0, &ProtectedModeBaseVector);

+  Status = Legacy8259->GetVector (Legacy8259, Efi8259Irq0, &ProtectedModeBaseVector);

   ASSERT_EFI_ERROR (Status);

 

   //

@@ -108,6 +119,19 @@ InitializeInterruptRedirection (
   return ;

 }

 

+/**

+  Thunk to 16-bit real mode and execute a software interrupt with a vector 

+  of BiosInt. Regs will contain the 16-bit register context on entry and 

+  exit.

+  

+  @param  This    Protocol instance pointer.

+  @param  BiosInt Processor interrupt vector to invoke

+  @param  Reg     Register contexted passed into (and returned) from thunk to 16-bit mode

+  

+  @retval TRUE   Thunk completed, and there were no BIOS errors in the target code.

+                 See Regs for status.

+  @retval FALSE  There was a BIOS erro in the target code.  

+**/

 BOOLEAN

 EFIAPI

 LegacyBiosInt86 (

@@ -115,25 +139,6 @@ LegacyBiosInt86 (
   IN  UINT8                           BiosInt,

   IN  EFI_IA32_REGISTER_SET           *Regs

   )

-/*++

-

-  Routine Description:

-    Thunk to 16-bit real mode and execute a software interrupt with a vector 

-    of BiosInt. Regs will contain the 16-bit register context on entry and 

-    exit.

-

-  Arguments:

-    This    - Protocol instance pointer.

-    BiosInt - Processor interrupt vector to invoke

-    Reg     - Register contexted passed into (and returned) from thunk to 

-              16-bit mode

-

-  Returns:

-    FALSE   - Thunk completed, and there were no BIOS errors in the target code.

-              See Regs for status.

-    TRUE    - There was a BIOS erro in the target code.

-

---*/

 {

   UINTN                 Status;

   UINTN                 Eflags;

@@ -178,7 +183,7 @@ LegacyBiosInt86 (
   Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259LegacyMode, NULL, NULL);

   ASSERT_EFI_ERROR (Status);

   

-  Stack16 = (UINT16 *)((UINT8 *) mThunkContext.RealModeBuffer + mThunkContext.RealModeBufferSize - sizeof (UINT16));

+  Stack16 = (UINT16 *)((UINT8 *) BiosDev->ThunkContext->RealModeBuffer + BiosDev->ThunkContext->RealModeBufferSize - sizeof (UINT16));

   Stack16 -= sizeof (ThunkRegSet.E.EFLAGS) / sizeof (UINT16);

   CopyMem (Stack16, &ThunkRegSet.E.EFLAGS, sizeof (ThunkRegSet.E.EFLAGS));

 

@@ -186,8 +191,8 @@ LegacyBiosInt86 (
   ThunkRegSet.E.ESP  = (UINT16) (UINTN) Stack16;

   ThunkRegSet.E.Eip  = (UINT16)((UINT32 *)NULL)[BiosInt];

   ThunkRegSet.E.CS   = (UINT16)(((UINT32 *)NULL)[BiosInt] >> 16);

-  mThunkContext.RealModeState = &ThunkRegSet;

-  AsmThunk16 (&mThunkContext);

+  BiosDev->ThunkContext->RealModeState = &ThunkRegSet;

+  AsmThunk16 (BiosDev->ThunkContext);

 

   //

   // Restore protected mode interrupt state