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Diffstat (limited to 'sys/contrib/dev/acpica/utilities/utlock.c')
-rw-r--r-- | sys/contrib/dev/acpica/utilities/utlock.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/sys/contrib/dev/acpica/utilities/utlock.c b/sys/contrib/dev/acpica/utilities/utlock.c new file mode 100644 index 0000000..cbe1cb9 --- /dev/null +++ b/sys/contrib/dev/acpica/utilities/utlock.c @@ -0,0 +1,277 @@ +/****************************************************************************** + * + * Module Name: utlock - Reader/Writer lock interfaces + * + *****************************************************************************/ + +/****************************************************************************** + * + * 1. Copyright Notice + * + * Some or all of this work - Copyright (c) 1999 - 2009, Intel Corp. + * All rights reserved. + * + * 2. License + * + * 2.1. This is your license from Intel Corp. under its intellectual property + * rights. You may have additional license terms from the party that provided + * you this software, covering your right to use that party's intellectual + * property rights. + * + * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a + * copy of the source code appearing in this file ("Covered Code") an + * irrevocable, perpetual, worldwide license under Intel's copyrights in the + * base code distributed originally by Intel ("Original Intel Code") to copy, + * make derivatives, distribute, use and display any portion of the Covered + * Code in any form, with the right to sublicense such rights; and + * + * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent + * license (with the right to sublicense), under only those claims of Intel + * patents that are infringed by the Original Intel Code, to make, use, sell, + * offer to sell, and import the Covered Code and derivative works thereof + * solely to the minimum extent necessary to exercise the above copyright + * license, and in no event shall the patent license extend to any additions + * to or modifications of the Original Intel Code. No other license or right + * is granted directly or by implication, estoppel or otherwise; + * + * The above copyright and patent license is granted only if the following + * conditions are met: + * + * 3. Conditions + * + * 3.1. Redistribution of Source with Rights to Further Distribute Source. + * Redistribution of source code of any substantial portion of the Covered + * Code or modification with rights to further distribute source must include + * the above Copyright Notice, the above License, this list of Conditions, + * and the following Disclaimer and Export Compliance provision. In addition, + * Licensee must cause all Covered Code to which Licensee contributes to + * contain a file documenting the changes Licensee made to create that Covered + * Code and the date of any change. Licensee must include in that file the + * documentation of any changes made by any predecessor Licensee. Licensee + * must include a prominent statement that the modification is derived, + * directly or indirectly, from Original Intel Code. + * + * 3.2. Redistribution of Source with no Rights to Further Distribute Source. + * Redistribution of source code of any substantial portion of the Covered + * Code or modification without rights to further distribute source must + * include the following Disclaimer and Export Compliance provision in the + * documentation and/or other materials provided with distribution. In + * addition, Licensee may not authorize further sublicense of source of any + * portion of the Covered Code, and must include terms to the effect that the + * license from Licensee to its licensee is limited to the intellectual + * property embodied in the software Licensee provides to its licensee, and + * not to intellectual property embodied in modifications its licensee may + * make. + * + * 3.3. Redistribution of Executable. Redistribution in executable form of any + * substantial portion of the Covered Code or modification must reproduce the + * above Copyright Notice, and the following Disclaimer and Export Compliance + * provision in the documentation and/or other materials provided with the + * distribution. + * + * 3.4. Intel retains all right, title, and interest in and to the Original + * Intel Code. + * + * 3.5. Neither the name Intel nor any other trademark owned or controlled by + * Intel shall be used in advertising or otherwise to promote the sale, use or + * other dealings in products derived from or relating to the Covered Code + * without prior written authorization from Intel. + * + * 4. Disclaimer and Export Compliance + * + * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED + * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE + * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE, + * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY + * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY + * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A + * PARTICULAR PURPOSE. + * + * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES + * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR + * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT, + * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY + * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL + * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS + * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY + * LIMITED REMEDY. + * + * 4.3. Licensee shall not export, either directly or indirectly, any of this + * software or system incorporating such software without first obtaining any + * required license or other approval from the U. S. Department of Commerce or + * any other agency or department of the United States Government. In the + * event Licensee exports any such software from the United States or + * re-exports any such software from a foreign destination, Licensee shall + * ensure that the distribution and export/re-export of the software is in + * compliance with all laws, regulations, orders, or other restrictions of the + * U.S. Export Administration Regulations. Licensee agrees that neither it nor + * any of its subsidiaries will export/re-export any technical data, process, + * software, or service, directly or indirectly, to any country for which the + * United States government or any agency thereof requires an export license, + * other governmental approval, or letter of assurance, without first obtaining + * such license, approval or letter. + * + *****************************************************************************/ + +#define __UTLOCK_C__ + +#include <contrib/dev/acpica/include/acpi.h> +#include <contrib/dev/acpica/include/accommon.h> + + +#define _COMPONENT ACPI_UTILITIES + ACPI_MODULE_NAME ("utlock") + + +/******************************************************************************* + * + * FUNCTION: AcpiUtCreateRwLock + * AcpiUtDeleteRwLock + * + * PARAMETERS: Lock - Pointer to a valid RW lock + * + * RETURN: Status + * + * DESCRIPTION: Reader/writer lock creation and deletion interfaces. + * + ******************************************************************************/ + +ACPI_STATUS +AcpiUtCreateRwLock ( + ACPI_RW_LOCK *Lock) +{ + ACPI_STATUS Status; + + + Lock->NumReaders = 0; + Status = AcpiOsCreateMutex (&Lock->ReaderMutex); + if (ACPI_FAILURE (Status)) + { + return (Status); + } + + Status = AcpiOsCreateMutex (&Lock->WriterMutex); + return (Status); +} + + +void +AcpiUtDeleteRwLock ( + ACPI_RW_LOCK *Lock) +{ + + AcpiOsDeleteMutex (Lock->ReaderMutex); + AcpiOsDeleteMutex (Lock->WriterMutex); + + Lock->NumReaders = 0; + Lock->ReaderMutex = NULL; + Lock->WriterMutex = NULL; +} + + +/******************************************************************************* + * + * FUNCTION: AcpiUtAcquireReadLock + * AcpiUtReleaseReadLock + * + * PARAMETERS: Lock - Pointer to a valid RW lock + * + * RETURN: Status + * + * DESCRIPTION: Reader interfaces for reader/writer locks. On acquisition, + * only the first reader acquires the write mutex. On release, + * only the last reader releases the write mutex. Although this + * algorithm can in theory starve writers, this should not be a + * problem with ACPICA since the subsystem is infrequently used + * in comparison to (for example) an I/O system. + * + ******************************************************************************/ + +ACPI_STATUS +AcpiUtAcquireReadLock ( + ACPI_RW_LOCK *Lock) +{ + ACPI_STATUS Status; + + + Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER); + if (ACPI_FAILURE (Status)) + { + return (Status); + } + + /* Acquire the write lock only for the first reader */ + + Lock->NumReaders++; + if (Lock->NumReaders == 1) + { + Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER); + } + + AcpiOsReleaseMutex (Lock->ReaderMutex); + return (Status); +} + + +ACPI_STATUS +AcpiUtReleaseReadLock ( + ACPI_RW_LOCK *Lock) +{ + ACPI_STATUS Status; + + + Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER); + if (ACPI_FAILURE (Status)) + { + return (Status); + } + + /* Release the write lock only for the very last reader */ + + Lock->NumReaders--; + if (Lock->NumReaders == 0) + { + AcpiOsReleaseMutex (Lock->WriterMutex); + } + + AcpiOsReleaseMutex (Lock->ReaderMutex); + return (Status); +} + + +/******************************************************************************* + * + * FUNCTION: AcpiUtAcquireWriteLock + * AcpiUtReleaseWriteLock + * + * PARAMETERS: Lock - Pointer to a valid RW lock + * + * RETURN: Status + * + * DESCRIPTION: Writer interfaces for reader/writer locks. Simply acquire or + * release the writer mutex associated with the lock. Acquisition + * of the lock is fully exclusive and will block all readers and + * writers until it is released. + * + ******************************************************************************/ + +ACPI_STATUS +AcpiUtAcquireWriteLock ( + ACPI_RW_LOCK *Lock) +{ + ACPI_STATUS Status; + + + Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER); + return (Status); +} + + +void +AcpiUtReleaseWriteLock ( + ACPI_RW_LOCK *Lock) +{ + + AcpiOsReleaseMutex (Lock->WriterMutex); +} + |