evmisc.c

acpi tools for linux include acpiexec and acpixtract

            HandlerObj->Notify.Context);
    }

    /* All done with the info object */

    AcpiUtDeleteGenericState (NotifyInfo);
}


/*******************************************************************************
 *
 * 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. Attempt to acquire the global lock,
 *              if successful, signal the thread waiting for the lock.
 *
 * NOTE: Assumes that the semaphore can be signaled from interrupt level. If
 * this is not possible for some reason, a separate thread will have to be
 * scheduled to do this.
 *
 ******************************************************************************/

static UINT32
AcpiEvGlobalLockHandler (
    void                    *Context)
{
    BOOLEAN                 Acquired = FALSE;
    ACPI_STATUS             Status;


    /*
     * Attempt to get the lock.
     *
     * If we don't get it now, it will be marked pending and we will
     * take another interrupt when it becomes free.
     */
    ACPI_ACQUIRE_GLOBAL_LOCK (Facs, Acquired);
    if (Acquired)
    {
        /* Got the lock, now wake the thread waiting for it */

        AcpiGbl_GlobalLockAcquired = TRUE;

        /* Send a unit to the semaphore */

        Status = AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore, 1);
        if (ACPI_FAILURE (Status))
        {
            ACPI_ERROR ((AE_INFO, "Could not signal Global Lock semaphore"));
        }
    }

    return (ACPI_INTERRUPT_HANDLED);
}


/*******************************************************************************
 *
 * 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);


    Status = AcpiGetTableByIndex (ACPI_TABLE_INDEX_FACS,
                ACPI_CAST_INDIRECT_PTR (ACPI_TABLE_HEADER, &Facs));
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    AcpiGbl_GlobalLockPresent = TRUE;
    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.
     */
    if (Status == AE_NO_HARDWARE_RESPONSE)
    {
        ACPI_ERROR ((AE_INFO,
            "No response from Global Lock hardware, disabling lock"));

        AcpiGbl_GlobalLockPresent = FALSE;
        Status = AE_OK;
    }

    return_ACPI_STATUS (Status);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiEvRemoveGlobalLockHandler
 *
 * PARAMETERS:  None
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Remove the handler for the Global Lock
 *
 ******************************************************************************/

static ACPI_STATUS
AcpiEvRemoveGlobalLockHandler (
    void)
{
    ACPI_STATUS             Status;


    ACPI_FUNCTION_TRACE (EvRemoveGlobalLockHandler);

    AcpiGbl_GlobalLockPresent = FALSE;
    Status = AcpiRemoveFixedEventHandler (ACPI_EVENT_GLOBAL,
                AcpiEvGlobalLockHandler);

    return_ACPI_STATUS (Status);
}


/******************************************************************************
 *
 * 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_STATUS             Status = AE_OK;
    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);
    }

    /* Attempt to acquire the actual hardware lock */

    ACPI_ACQUIRE_GLOBAL_LOCK (Facs, Acquired);
    if (Acquired)
    {
       /* We got the lock */

        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Acquired hardware Global Lock\n"));

        AcpiGbl_GlobalLockAcquired = TRUE;
        return_ACPI_STATUS (AE_OK);
    }

    /*
     * Did not get the lock. The pending bit was set above, and we must now
     * wait until we get the global lock released interrupt.
     */
    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);

    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 (Facs, Pending);

        /*
         * If the pending bit was set, we must write GBL_RLS to the control
         * register
         */
        if (Pending)
        {
            Status = AcpiSetRegister (
                        ACPI_BITREG_GLOBAL_LOCK_RELEASE, 1);
        }

        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);
}


/******************************************************************************
 *
 * FUNCTION:    AcpiEvTerminate
 *
 * PARAMETERS:  none
 *
 * RETURN:      none
 *
 * DESCRIPTION: Disable events and free memory allocated for table storage.
 *
 ******************************************************************************/

void
AcpiEvTerminate (
    void)
{
    ACPI_NATIVE_UINT        i;
    ACPI_STATUS             Status;


    ACPI_FUNCTION_TRACE (EvTerminate);


    if (AcpiGbl_EventsInitialized)
    {
        /*
         * Disable all event-related functionality.
         * In all cases, on error, print a message but obviously we don't abort.
         */

        /* Disable all fixed events */

        for (i = 0; i < ACPI_NUM_FIXED_EVENTS; i++)
        {
            Status = AcpiDisableEvent ((UINT32) i, 0);
            if (ACPI_FAILURE (Status))
            {
                ACPI_ERROR ((AE_INFO,
                    "Could not disable fixed event %d", (UINT32) i));
            }
        }

        /* Disable all GPEs in all GPE blocks */

        Status = AcpiEvWalkGpeList (AcpiHwDisableGpeBlock);

        /* Remove SCI handler */

        Status = AcpiEvRemoveSciHandler ();
        if (ACPI_FAILURE(Status))
        {
            ACPI_ERROR ((AE_INFO,
                "Could not remove SCI handler"));
        }

        Status = AcpiEvRemoveGlobalLockHandler ();
        if (ACPI_FAILURE(Status))
        {
            ACPI_ERROR ((AE_INFO,
                "Could not remove Global Lock handler"));
        }
    }

    /* Deallocate all handler objects installed within GPE info structs */

    Status = AcpiEvWalkGpeList (AcpiEvDeleteGpeHandlers);

    /* Return to original mode if necessary */

    if (AcpiGbl_OriginalMode == ACPI_SYS_MODE_LEGACY)
    {
        Status = AcpiDisable ();
        if (ACPI_FAILURE (Status))
        {
            ACPI_WARNING ((AE_INFO, "AcpiDisable failed"));
        }
    }
    return_VOID;
}