/******************************************************************************
*
* Module Name: evglock - Global Lock support
*
*****************************************************************************/
/******************************************************************************
*
* 1. Copyright Notice
*
* Some or all of this work - Copyright (c) 1999 - 2011, 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.
*
*****************************************************************************/
#include "acpi.h"
#include "accommon.h"
#include "acevents.h"
#include "acinterp.h"
#define _COMPONENT ACPI_EVENTS
ACPI_MODULE_NAME ("evglock")
/* 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);
/* 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);
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);
}