/******************************************************************************
*
* Module Name: evglock - Global Lock support
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2022, Intel Corp.
* All rights reserved.
*
* 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.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* 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
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
*/
#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 */