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/****************************************************************************** |
* |
* Module Name: evglock - Global Lock support |
* |
*****************************************************************************/ |
|
/* |
* Copyright (C) 2000 - 2015, 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 MERCHANTIBILITY 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/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 u32 acpi_ev_global_lock_handler(void *context); |
|
/******************************************************************************* |
* |
* FUNCTION: acpi_ev_init_global_lock_handler |
* |
* PARAMETERS: None |
* |
* RETURN: Status |
* |
* DESCRIPTION: Install a handler for the global lock release event |
* |
******************************************************************************/ |
|
acpi_status acpi_ev_init_global_lock_handler(void) |
{ |
acpi_status status; |
|
ACPI_FUNCTION_TRACE(ev_init_global_lock_handler); |
|
/* If Hardware Reduced flag is set, there is no global lock */ |
|
if (acpi_gbl_reduced_hardware) { |
return_ACPI_STATUS(AE_OK); |
} |
|
/* Attempt installation of the global lock handler */ |
|
status = acpi_install_fixed_event_handler(ACPI_EVENT_GLOBAL, |
acpi_ev_global_lock_handler, |
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. |
*/ |
acpi_gbl_global_lock_present = 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 = acpi_os_create_lock(&acpi_gbl_global_lock_pending_lock); |
if (ACPI_FAILURE(status)) { |
return_ACPI_STATUS(status); |
} |
|
acpi_gbl_global_lock_pending = FALSE; |
acpi_gbl_global_lock_present = TRUE; |
return_ACPI_STATUS(status); |
} |
|
/******************************************************************************* |
* |
* FUNCTION: acpi_ev_remove_global_lock_handler |
* |
* PARAMETERS: None |
* |
* RETURN: Status |
* |
* DESCRIPTION: Remove the handler for the Global Lock |
* |
******************************************************************************/ |
|
acpi_status acpi_ev_remove_global_lock_handler(void) |
{ |
acpi_status status; |
|
ACPI_FUNCTION_TRACE(ev_remove_global_lock_handler); |
|
acpi_gbl_global_lock_present = FALSE; |
status = acpi_remove_fixed_event_handler(ACPI_EVENT_GLOBAL, |
acpi_ev_global_lock_handler); |
|
acpi_os_delete_lock(acpi_gbl_global_lock_pending_lock); |
return_ACPI_STATUS(status); |
} |
|
/******************************************************************************* |
* |
* FUNCTION: acpi_ev_global_lock_handler |
* |
* 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 u32 acpi_ev_global_lock_handler(void *context) |
{ |
acpi_status status; |
acpi_cpu_flags flags; |
|
flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock); |
|
/* |
* 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 (!acpi_gbl_global_lock_pending) { |
goto cleanup_and_exit; |
} |
|
/* |
* Send a unit to the global lock semaphore. The actual acquisition |
* of the global lock will be performed by the waiting thread. |
*/ |
status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1); |
if (ACPI_FAILURE(status)) { |
ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore")); |
} |
|
acpi_gbl_global_lock_pending = FALSE; |
|
cleanup_and_exit: |
|
acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags); |
return (ACPI_INTERRUPT_HANDLED); |
} |
|
/****************************************************************************** |
* |
* FUNCTION: acpi_ev_acquire_global_lock |
* |
* 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 acpi_ev_acquire_global_lock(u16 timeout) |
{ |
acpi_cpu_flags flags; |
acpi_status status; |
u8 acquired = FALSE; |
|
ACPI_FUNCTION_TRACE(ev_acquire_global_lock); |
|
/* |
* Only one thread can acquire the GL at a time, the global_lock_mutex |
* enforces this. This interface releases the interpreter if we must wait. |
*/ |
status = |
acpi_ex_system_wait_mutex(acpi_gbl_global_lock_mutex->mutex. |
os_mutex, 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 acpi_acquire_global_lock interfaces. The |
* handle is therefore updated on the first acquire from a given thread |
* regardless of where the acquisition request originated. |
*/ |
acpi_gbl_global_lock_handle++; |
if (acpi_gbl_global_lock_handle == 0) { |
acpi_gbl_global_lock_handle = 1; |
} |
|
/* |
* Make sure that a global lock actually exists. If not, just |
* treat the lock as a standard mutex. |
*/ |
if (!acpi_gbl_global_lock_present) { |
acpi_gbl_global_lock_acquired = TRUE; |
return_ACPI_STATUS(AE_OK); |
} |
|
flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock); |
|
do { |
|
/* Attempt to acquire the actual hardware lock */ |
|
ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired); |
if (acquired) { |
acpi_gbl_global_lock_acquired = 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. |
*/ |
acpi_gbl_global_lock_pending = TRUE; |
acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, 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 = |
acpi_ex_system_wait_semaphore |
(acpi_gbl_global_lock_semaphore, ACPI_WAIT_FOREVER); |
|
flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock); |
|
} while (ACPI_SUCCESS(status)); |
|
acpi_gbl_global_lock_pending = FALSE; |
acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags); |
|
return_ACPI_STATUS(status); |
} |
|
/******************************************************************************* |
* |
* FUNCTION: acpi_ev_release_global_lock |
* |
* PARAMETERS: None |
* |
* RETURN: Status |
* |
* DESCRIPTION: Releases ownership of the Global Lock. |
* |
******************************************************************************/ |
|
acpi_status acpi_ev_release_global_lock(void) |
{ |
u8 pending = FALSE; |
acpi_status status = AE_OK; |
|
ACPI_FUNCTION_TRACE(ev_release_global_lock); |
|
/* Lock must be already acquired */ |
|
if (!acpi_gbl_global_lock_acquired) { |
ACPI_WARNING((AE_INFO, |
"Cannot release the ACPI Global Lock, it has not been acquired")); |
return_ACPI_STATUS(AE_NOT_ACQUIRED); |
} |
|
if (acpi_gbl_global_lock_present) { |
|
/* Allow any thread to release the lock */ |
|
ACPI_RELEASE_GLOBAL_LOCK(acpi_gbl_FACS, pending); |
|
/* |
* If the pending bit was set, we must write GBL_RLS to the control |
* register |
*/ |
if (pending) { |
status = |
acpi_write_bit_register |
(ACPI_BITREG_GLOBAL_LOCK_RELEASE, |
ACPI_ENABLE_EVENT); |
} |
|
ACPI_DEBUG_PRINT((ACPI_DB_EXEC, |
"Released hardware Global Lock\n")); |
} |
|
acpi_gbl_global_lock_acquired = FALSE; |
|
/* Release the local GL mutex */ |
|
acpi_os_release_mutex(acpi_gbl_global_lock_mutex->mutex.os_mutex); |
return_ACPI_STATUS(status); |
} |
|
#endif /* !ACPI_REDUCED_HARDWARE */ |