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 /******************************************************************************
  *
  * Module Name: evglock - Global Lock support
  *
  *****************************************************************************/
 
 /******************************************************************************
  *
  * 1. Copyright Notice
  *
  * Some or all of this work - Copyright (c) 1999 - 2024, 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.
  *
  *****************************************************************************
  *
  * Alternatively, you may choose to be licensed under the terms of the
  * following license:
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions, and the following disclaimer,
  *    without modification.
  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  *    substantially similar to the "NO WARRANTY" disclaimer below
  *    ("Disclaimer") and any redistribution must be conditioned upon
  *    including a substantially similar Disclaimer requirement for further
  *    binary redistribution.
  * 3. Neither the names of the above-listed copyright holders nor the names
  *    of any contributors may be used to endorse or promote products derived
  *    from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * Alternatively, you may choose to be licensed under the terms of the
  * GNU General Public License ("GPL") version 2 as published by the Free
  * Software Foundation.
  *
  *****************************************************************************/
 
 #include "acpi.h"
 #include "accommon.h"
 #include "acevents.h"
 #include "acinterp.h"
 
 #define _COMPONENT          ACPI_EVENTS
         ACPI_MODULE_NAME    ("evglock")
 
 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */
 
 /* Local prototypes */
 
 static UINT32
 AcpiEvGlobalLockHandler (
     void                    *Context);
 
 
 /*******************************************************************************
  *
  * FUNCTION:    AcpiEvInitGlobalLockHandler
  *
  * PARAMETERS:  None
  *
  * RETURN:      Status
  *
  * DESCRIPTION: Install a handler for the global lock release event
  *
  ******************************************************************************/
 
 ACPI_STATUS
 AcpiEvInitGlobalLockHandler (
     void)
 {
     ACPI_STATUS             Status;
 
 
     ACPI_FUNCTION_TRACE (EvInitGlobalLockHandler);
 
 
     /* If Hardware Reduced flag is set, there is no global lock */
 
     if (AcpiGbl_ReducedHardware)
     {
         return_ACPI_STATUS (AE_OK);
     }
 
     /* Attempt installation of the global lock handler */
 
     Status = AcpiInstallFixedEventHandler (ACPI_EVENT_GLOBAL,
         AcpiEvGlobalLockHandler, NULL);
 
     /*
      * If the global lock does not exist on this platform, the attempt to
      * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick).
      * Map to AE_OK, but mark global lock as not present. Any attempt to
      * actually use the global lock will be flagged with an error.
      */
     AcpiGbl_GlobalLockPresent = FALSE;
     if (Status == AE_NO_HARDWARE_RESPONSE)
     {
         ACPI_ERROR ((AE_INFO,
             "No response from Global Lock hardware, disabling lock"));
 
         return_ACPI_STATUS (AE_OK);
     }
 
     Status = AcpiOsCreateLock (&AcpiGbl_GlobalLockPendingLock);
     if (ACPI_FAILURE (Status))
     {
         return_ACPI_STATUS (Status);
     }
 
     AcpiGbl_GlobalLockPending = FALSE;
     AcpiGbl_GlobalLockPresent = TRUE;
     return_ACPI_STATUS (Status);
 }
 
 
 /*******************************************************************************
  *
  * FUNCTION:    AcpiEvRemoveGlobalLockHandler
  *
  * PARAMETERS:  None
  *
  * RETURN:      Status
  *
  * DESCRIPTION: Remove the handler for the Global Lock
  *
  ******************************************************************************/
 
 ACPI_STATUS
 AcpiEvRemoveGlobalLockHandler (
     void)
 {
     ACPI_STATUS             Status;
 
 
     ACPI_FUNCTION_TRACE (EvRemoveGlobalLockHandler);
 
 
     AcpiGbl_GlobalLockPresent = FALSE;
     Status = AcpiRemoveFixedEventHandler (ACPI_EVENT_GLOBAL,
         AcpiEvGlobalLockHandler);
 
     AcpiOsDeleteLock (AcpiGbl_GlobalLockPendingLock);
     return_ACPI_STATUS (Status);
 }
 
 
 /*******************************************************************************
  *
  * FUNCTION:    AcpiEvGlobalLockHandler
  *
  * PARAMETERS:  Context         - From thread interface, not used
  *
  * RETURN:      ACPI_INTERRUPT_HANDLED
  *
  * DESCRIPTION: Invoked directly from the SCI handler when a global lock
  *              release interrupt occurs. If there is actually a pending
  *              request for the lock, signal the waiting thread.
  *
  ******************************************************************************/
 
 static UINT32
 AcpiEvGlobalLockHandler (
     void                    *Context)
 {
     ACPI_STATUS             Status;
     ACPI_CPU_FLAGS          Flags;
 
 
     Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
 
     /*
      * If a request for the global lock is not actually pending,
      * we are done. This handles "spurious" global lock interrupts
      * which are possible (and have been seen) with bad BIOSs.
      */
     if (!AcpiGbl_GlobalLockPending)
     {
         goto CleanupAndExit;
     }
 
     /*
      * Send a unit to the global lock semaphore. The actual acquisition
      * of the global lock will be performed by the waiting thread.
      */
     Status = AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore, 1);
     if (ACPI_FAILURE (Status))
     {
         ACPI_ERROR ((AE_INFO, "Could not signal Global Lock semaphore"));
     }
 
     AcpiGbl_GlobalLockPending = FALSE;
 
 
 CleanupAndExit:
 
     AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
     return (ACPI_INTERRUPT_HANDLED);
 }
 
 
 /******************************************************************************
  *
  * FUNCTION:    AcpiEvAcquireGlobalLock
  *
  * PARAMETERS:  Timeout         - Max time to wait for the lock, in millisec.
  *
  * RETURN:      Status
  *
  * DESCRIPTION: Attempt to gain ownership of the Global Lock.
  *
  * MUTEX:       Interpreter must be locked
  *
  * Note: The original implementation allowed multiple threads to "acquire" the
  * Global Lock, and the OS would hold the lock until the last thread had
  * released it. However, this could potentially starve the BIOS out of the
  * lock, especially in the case where there is a tight handshake between the
  * Embedded Controller driver and the BIOS. Therefore, this implementation
  * allows only one thread to acquire the HW Global Lock at a time, and makes
  * the global lock appear as a standard mutex on the OS side.
  *
  *****************************************************************************/
 
 ACPI_STATUS
 AcpiEvAcquireGlobalLock (
     UINT16                  Timeout)
 {
     ACPI_CPU_FLAGS          Flags;
     ACPI_STATUS             Status;
     BOOLEAN                 Acquired = FALSE;
 
 
     ACPI_FUNCTION_TRACE (EvAcquireGlobalLock);
 
 
     /*
      * Only one thread can acquire the GL at a time, the GlobalLockMutex
      * enforces this. This interface releases the interpreter if we must wait.
      */
     Status = AcpiExSystemWaitMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex,
                 Timeout);
     if (ACPI_FAILURE (Status))
     {
         return_ACPI_STATUS (Status);
     }
 
     /*
      * Update the global lock handle and check for wraparound. The handle is
      * only used for the external global lock interfaces, but it is updated
      * here to properly handle the case where a single thread may acquire the
      * lock via both the AML and the AcpiAcquireGlobalLock interfaces. The
      * handle is therefore updated on the first acquire from a given thread
      * regardless of where the acquisition request originated.
      */
     AcpiGbl_GlobalLockHandle++;
     if (AcpiGbl_GlobalLockHandle == 0)
     {
         AcpiGbl_GlobalLockHandle = 1;
     }
 
     /*
      * Make sure that a global lock actually exists. If not, just
      * treat the lock as a standard mutex.
      */
     if (!AcpiGbl_GlobalLockPresent)
     {
         AcpiGbl_GlobalLockAcquired = TRUE;
         return_ACPI_STATUS (AE_OK);
     }
 
     Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
 
     do
     {
         /* Attempt to acquire the actual hardware lock */
 
         ACPI_ACQUIRE_GLOBAL_LOCK (AcpiGbl_FACS, Acquired);
         if (Acquired)
         {
             AcpiGbl_GlobalLockAcquired = TRUE;
             ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
                 "Acquired hardware Global Lock\n"));
             break;
         }
 
         /*
          * Did not get the lock. The pending bit was set above, and
          * we must now wait until we receive the global lock
          * released interrupt.
          */
         AcpiGbl_GlobalLockPending = TRUE;
         AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
 
         ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
             "Waiting for hardware Global Lock\n"));
 
         /*
          * Wait for handshake with the global lock interrupt handler.
          * This interface releases the interpreter if we must wait.
          */
         Status = AcpiExSystemWaitSemaphore (
             AcpiGbl_GlobalLockSemaphore, ACPI_WAIT_FOREVER);
 
         Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
 
     } while (ACPI_SUCCESS (Status));
 
     AcpiGbl_GlobalLockPending = FALSE;
     AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
 
     return_ACPI_STATUS (Status);
 }
 
 
 /*******************************************************************************
  *
  * FUNCTION:    AcpiEvReleaseGlobalLock
  *
  * PARAMETERS:  None
  *
  * RETURN:      Status
  *
  * DESCRIPTION: Releases ownership of the Global Lock.
  *
  ******************************************************************************/
 
 ACPI_STATUS
 AcpiEvReleaseGlobalLock (
     void)
 {
     BOOLEAN                 Pending = FALSE;
     ACPI_STATUS             Status = AE_OK;
 
 
     ACPI_FUNCTION_TRACE (EvReleaseGlobalLock);
 
 
     /* Lock must be already acquired */
 
     if (!AcpiGbl_GlobalLockAcquired)
     {
         ACPI_WARNING ((AE_INFO,
             "Cannot release the ACPI Global Lock, it has not been acquired"));
         return_ACPI_STATUS (AE_NOT_ACQUIRED);
     }
 
     if (AcpiGbl_GlobalLockPresent)
     {
         /* Allow any thread to release the lock */
 
         ACPI_RELEASE_GLOBAL_LOCK (AcpiGbl_FACS, Pending);
 
         /*
          * If the pending bit was set, we must write GBL_RLS to the control
          * register
          */
         if (Pending)
         {
             Status = AcpiWriteBitRegister (
                 ACPI_BITREG_GLOBAL_LOCK_RELEASE, ACPI_ENABLE_EVENT);
         }
 
         ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Released hardware Global Lock\n"));
     }
 
     AcpiGbl_GlobalLockAcquired = FALSE;
 
     /* Release the local GL mutex */
 
     AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex);
     return_ACPI_STATUS (Status);
 }
 
 #endif /* !ACPI_REDUCED_HARDWARE */

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