diff options
Diffstat (limited to 'EDK/Foundation/Library/Dxe/EfiDriverLib/Lock.c')
-rw-r--r-- | EDK/Foundation/Library/Dxe/EfiDriverLib/Lock.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/EDK/Foundation/Library/Dxe/EfiDriverLib/Lock.c b/EDK/Foundation/Library/Dxe/EfiDriverLib/Lock.c new file mode 100644 index 0000000..f9d1006 --- /dev/null +++ b/EDK/Foundation/Library/Dxe/EfiDriverLib/Lock.c @@ -0,0 +1,159 @@ +/*++ + +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. + +--*/ + +#include "Tiano.h" +#include "EfiDriverLib.h" + +VOID +EfiInitializeLock ( + IN OUT EFI_LOCK *Lock, + IN EFI_TPL Priority + ) +/*++ + +Routine Description: + + Initialize a basic mutual exclusion lock. Each lock + provides mutual exclusion access at it's task priority + level. Since there is no-premption (at any TPL) or + multiprocessor support, acquiring the lock only consists + of raising to the locks TPL. + + Note on a check build ASSERT()s are used to ensure proper + lock usage. + +Arguments: + + Lock - The EFI_LOCK structure to initialize + + Priority - The task priority level of the lock + + +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. Each lock + provides mutual exclusion access at it's task priority + level. Since there is no-premption (at any TPL) or + multiprocessor support, acquiring the lock only consists + of raising to the locks TPL. + +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; + } + + Lock->OwnerTpl = gBS->RaiseTPL (Lock->Tpl); + + Lock->Lock += 1; + return EFI_SUCCESS; +} + +VOID +EfiAcquireLock ( + IN EFI_LOCK *Lock + ) +/*++ + +Routine Description: + + Raising to the task priority level of the mutual exclusion + lock, and then 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, and + restores the previous task priority level. + +Arguments: + + Lock - The lock to release + +Returns: + + Lock unowned + +--*/ +{ + EFI_TPL Tpl; + + Tpl = Lock->OwnerTpl; + + ASSERT (Lock->Lock == 1); + Lock->Lock -= 1; + + gBS->RestoreTPL (Tpl); +} |