3  * Module Name: evglock - Global Lock support
11  * Some or all of this work - Copyright (c) 1999 - 2025, Intel Corp.
28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
104  * re-exports any such software from a foreign destination, Licensee shall
105  * ensure that the distribution and export/re-export of the software is in
108  * any of its subsidiaries will export/re-export any technical data, process,
130  * 3. Neither the names of the above-listed copyright holders nor the names
175  * RETURN:      Status
177  * DESCRIPTION: Install a handler for the global lock release event
185     ACPI_STATUS             Status;  in AcpiEvInitGlobalLockHandler()  local
191     /* If Hardware Reduced flag is set, there is no global lock */  in AcpiEvInitGlobalLockHandler()
203     /* Attempt installation of the global lock handler */  in AcpiEvInitGlobalLockHandler()
205     Status = AcpiInstallFixedEventHandler (ACPI_EVENT_GLOBAL,  in AcpiEvInitGlobalLockHandler()
209      * If the global lock does not exist on this platform, the attempt to  in AcpiEvInitGlobalLockHandler()
211      * Map to AE_OK, but mark global lock as not present. Any attempt to  in AcpiEvInitGlobalLockHandler()
212      * actually use the global lock will be flagged with an error.  in AcpiEvInitGlobalLockHandler()
215     if (Status == AE_NO_HARDWARE_RESPONSE)  in AcpiEvInitGlobalLockHandler()
218             "No response from Global Lock hardware, disabling lock"));  in AcpiEvInitGlobalLockHandler()
223     Status = AcpiOsCreateLock (&AcpiGbl_GlobalLockPendingLock);  in AcpiEvInitGlobalLockHandler()
224     if (ACPI_FAILURE (Status))  in AcpiEvInitGlobalLockHandler()
226         return_ACPI_STATUS (Status);  in AcpiEvInitGlobalLockHandler()
231     return_ACPI_STATUS (Status);  in AcpiEvInitGlobalLockHandler()
241  * RETURN:      Status
243  * DESCRIPTION: Remove the handler for the Global Lock
251     ACPI_STATUS             Status;  in AcpiEvRemoveGlobalLockHandler()  local
258     Status = AcpiRemoveFixedEventHandler (ACPI_EVENT_GLOBAL,  in AcpiEvRemoveGlobalLockHandler()
262     return_ACPI_STATUS (Status);  in AcpiEvRemoveGlobalLockHandler()
270  * PARAMETERS:  Context         - From thread interface, not used
274  * DESCRIPTION: Invoked directly from the SCI handler when a global lock
276  *              request for the lock, signal the waiting thread.
284     ACPI_STATUS             Status;  in AcpiEvGlobalLockHandler()  local
291      * If a request for the global lock is not actually pending,  in AcpiEvGlobalLockHandler()
292      * we are done. This handles "spurious" global lock interrupts  in AcpiEvGlobalLockHandler()
301      * Send a unit to the global lock semaphore. The actual acquisition  in AcpiEvGlobalLockHandler()
302      * of the global lock will be performed by the waiting thread.  in AcpiEvGlobalLockHandler()
304     Status = AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore, 1);  in AcpiEvGlobalLockHandler()
305     if (ACPI_FAILURE (Status))  in AcpiEvGlobalLockHandler()
307         ACPI_ERROR ((AE_INFO, "Could not signal Global Lock semaphore"));  in AcpiEvGlobalLockHandler()
324  * PARAMETERS:  Timeout         - Max time to wait for the lock, in millisec.
326  * RETURN:      Status
328  * DESCRIPTION: Attempt to gain ownership of the Global Lock.
333  * Global Lock, and the OS would hold the lock until the last thread had
335  * lock, especially in the case where there is a tight handshake between the
337  * allows only one thread to acquire the HW Global Lock at a time, and makes
338  * the global lock appear as a standard mutex on the OS side.
347     ACPI_STATUS             Status;  in AcpiEvAcquireGlobalLock()  local
358     Status = AcpiExSystemWaitMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex,  in AcpiEvAcquireGlobalLock()
360     if (ACPI_FAILURE (Status))  in AcpiEvAcquireGlobalLock()
362         return_ACPI_STATUS (Status);  in AcpiEvAcquireGlobalLock()
366      * Update the global lock handle and check for wraparound. The handle is  in AcpiEvAcquireGlobalLock()
367      * only used for the external global lock interfaces, but it is updated  in AcpiEvAcquireGlobalLock()
369      * lock via both the AML and the AcpiAcquireGlobalLock interfaces. The  in AcpiEvAcquireGlobalLock()
380      * Make sure that a global lock actually exists. If not, just  in AcpiEvAcquireGlobalLock()
381      * treat the lock as a standard mutex.  in AcpiEvAcquireGlobalLock()
393         /* Attempt to acquire the actual hardware lock */  in AcpiEvAcquireGlobalLock()
400                 "Acquired hardware Global Lock\n"));  in AcpiEvAcquireGlobalLock()
405          * Did not get the lock. The pending bit was set above, and  in AcpiEvAcquireGlobalLock()
406          * we must now wait until we receive the global lock  in AcpiEvAcquireGlobalLock()
413             "Waiting for hardware Global Lock\n"));  in AcpiEvAcquireGlobalLock()
416          * Wait for handshake with the global lock interrupt handler.  in AcpiEvAcquireGlobalLock()
419         Status = AcpiExSystemWaitSemaphore (  in AcpiEvAcquireGlobalLock()
424     } while (ACPI_SUCCESS (Status));  in AcpiEvAcquireGlobalLock()
429     return_ACPI_STATUS (Status);  in AcpiEvAcquireGlobalLock()
439  * RETURN:      Status
441  * DESCRIPTION: Releases ownership of the Global Lock.
450     ACPI_STATUS             Status = AE_OK;  in AcpiEvReleaseGlobalLock()  local
456     /* Lock must be already acquired */  in AcpiEvReleaseGlobalLock()
461             "Cannot release the ACPI Global Lock, it has not been acquired"));  in AcpiEvReleaseGlobalLock()
467         /* Allow any thread to release the lock */  in AcpiEvReleaseGlobalLock()
477             Status = AcpiWriteBitRegister (  in AcpiEvReleaseGlobalLock()
481         ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Released hardware Global Lock\n"));  in AcpiEvReleaseGlobalLock()
488     AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex);  in AcpiEvReleaseGlobalLock()
489     return_ACPI_STATUS (Status);  in AcpiEvReleaseGlobalLock()