Add in the 1st version of ECP.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2832 6f19259b-4bc3-4df7-8a09-765794883524

EdkCompatibilityPkg/Foundation/Library/RuntimeDxe/EfiRuntimeLib/Ipf/Lock.c

@@ -0,0 +1,170 @@
+/*++
+
+Copyright (c) 2004, 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.             
+
+Module Name:
+
+  Lock.c
+
+Abstract:
+
+  Support for locking lib services. These primitives may be implemented 
+  as Esal calls but since these result in small code that us position
+  independent, we can use lib functions. ESAL calls have a significant
+  software overhead and too deep nesting is bad for the stack.
+
+--*/
+
+#include "Tiano.h"
+#include "EfiDriverLib.h"
+
+extern
+BOOLEAN
+EfiAtRuntime (
+  VOID
+  );
+
+VOID
+EfiInitializeLock (
+  IN OUT EFI_LOCK *Lock,
+  IN EFI_TPL      Priority
+  )
+/*++
+
+Routine Description:
+
+  Initialize a basic mutual exclusion lock. There is 
+  no concept of TPL at runtime hence priority is
+  ignored.
+    
+Arguments:
+
+  Lock        - The EFI_LOCK structure to initialize
+
+  Priority    - Ignored
+
+    
+Returns:
+
+  An initialized Efi Lock structure.
+
+--*/
+{
+  Lock->Tpl       = Priority;
+  Lock->OwnerTpl  = 0;
+  Lock->Lock      = 0;
+}
+
+EFI_STATUS
+EfiAcquireLockOrFail (
+  IN EFI_LOCK  *Lock
+  )
+/*++
+
+Routine Description:
+
+  Initialize a basic mutual exclusion lock. For now,
+  only allow one level of nesting.
+    
+Arguments:
+
+  Lock        - The EFI_LOCK structure to initialize
+   
+Returns:
+
+  EFI_SUCCESS       - Lock Owned.
+  EFI_ACCESS_DENIED - Reentrant Lock Acquisition, Lock not Owned.
+
+--*/
+{
+  if (Lock->Lock != 0) {
+    //
+    // Lock is already owned, so bail out
+    //
+    return EFI_ACCESS_DENIED;
+  }
+
+  if (!EfiAtRuntime ()) {
+    //
+    // The check is just debug code for core inplementation. It must
+    //  always be true in a driver
+    //
+    Lock->OwnerTpl = gBS->RaiseTPL (Lock->Tpl);
+  }
+
+  Lock->Lock += 1;
+  return EFI_SUCCESS;
+}
+
+VOID
+EfiAcquireLock (
+  IN EFI_LOCK  *Lock
+  )
+/*++
+
+Routine Description:
+
+  Acquires ownership of the lock.
+    
+Arguments:
+
+  Lock - The lock to acquire
+    
+Returns:
+
+  Lock owned
+
+--*/
+{
+  EFI_STATUS  Status;
+
+  Status = EfiAcquireLockOrFail (Lock);
+
+  //
+  // Lock was already locked.
+  //
+  ASSERT_EFI_ERROR (Status);
+}
+
+VOID
+EfiReleaseLock (
+  IN EFI_LOCK  *Lock
+  )
+/*++
+
+Routine Description:
+
+    Releases ownership of the mutual exclusion lock.
+    
+Arguments:
+
+    Lock - The lock to release
+    
+Returns:
+
+    Lock unowned
+
+--*/
+{
+  EFI_TPL Tpl;
+
+  Tpl = Lock->OwnerTpl;
+
+  ASSERT (Lock->Lock == 1);
+  Lock->Lock -= 1;
+
+  if (!EfiAtRuntime ()) {
+    //
+    // The check is just debug code for core inplementation. It must
+    //  always be true in a driver
+    //
+    gBS->RestoreTPL (Tpl);
+  }
+}