path: root/drivers/acpi/utilities/utmutex.c

/*******************************************************************************
 *
 * Module Name: utmutex - local mutex support
 *
 ******************************************************************************/

/*
 * Copyright (C) 2000 - 2005, R. Byron Moore
 * 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>

#define _COMPONENT          ACPI_UTILITIES
	 ACPI_MODULE_NAME    ("utmutex")

/* Local prototypes */

static acpi_status
acpi_ut_create_mutex (
	acpi_mutex_handle               mutex_id);

static acpi_status
acpi_ut_delete_mutex (
	acpi_mutex_handle               mutex_id);


/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_mutex_initialize
 *
 * PARAMETERS:  None.
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create the system mutex objects.
 *
 ******************************************************************************/

acpi_status
acpi_ut_mutex_initialize (
	void)
{
	u32                             i;
	acpi_status                     status;


	ACPI_FUNCTION_TRACE ("ut_mutex_initialize");


	/*
	 * Create each of the predefined mutex objects
	 */
	for (i = 0; i < NUM_MUTEX; i++) {
		status = acpi_ut_create_mutex (i);
		if (ACPI_FAILURE (status)) {
			return_ACPI_STATUS (status);
		}
	}

	status = acpi_os_create_lock (&acpi_gbl_gpe_lock);
	return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_mutex_terminate
 *
 * PARAMETERS:  None.
 *
 * RETURN:      None.
 *
 * DESCRIPTION: Delete all of the system mutex objects.
 *
 ******************************************************************************/

void
acpi_ut_mutex_terminate (
	void)
{
	u32                             i;


	ACPI_FUNCTION_TRACE ("ut_mutex_terminate");


	/*
	 * Delete each predefined mutex object
	 */
	for (i = 0; i < NUM_MUTEX; i++) {
		(void) acpi_ut_delete_mutex (i);
	}

	acpi_os_delete_lock (acpi_gbl_gpe_lock);
	return_VOID;
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_create_mutex
 *
 * PARAMETERS:  mutex_iD        - ID of the mutex to be created
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create a mutex object.
 *
 ******************************************************************************/

static acpi_status
acpi_ut_create_mutex (
	acpi_mutex_handle               mutex_id)
{
	acpi_status                     status = AE_OK;


	ACPI_FUNCTION_TRACE_U32 ("ut_create_mutex", mutex_id);


	if (mutex_id > MAX_MUTEX) {
		return_ACPI_STATUS (AE_BAD_PARAMETER);
	}

	if (!acpi_gbl_mutex_info[mutex_id].mutex) {
		status = acpi_os_create_semaphore (1, 1,
				  &acpi_gbl_mutex_info[mutex_id].mutex);
		acpi_gbl_mutex_info[mutex_id].thread_id = ACPI_MUTEX_NOT_ACQUIRED;
		acpi_gbl_mutex_info[mutex_id].use_count = 0;
	}

	return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_delete_mutex
 *
 * PARAMETERS:  mutex_iD        - ID of the mutex to be deleted
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Delete a mutex object.
 *
 ******************************************************************************/

static acpi_status
acpi_ut_delete_mutex (
	acpi_mutex_handle               mutex_id)
{
	acpi_status                     status;


	ACPI_FUNCTION_TRACE_U32 ("ut_delete_mutex", mutex_id);


	if (mutex_id > MAX_MUTEX) {
		return_ACPI_STATUS (AE_BAD_PARAMETER);
	}

	status = acpi_os_delete_semaphore (acpi_gbl_mutex_info[mutex_id].mutex);

	acpi_gbl_mutex_info[mutex_id].mutex = NULL;
	acpi_gbl_mutex_info[mutex_id].thread_id = ACPI_MUTEX_NOT_ACQUIRED;

	return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_acquire_mutex
 *
 * PARAMETERS:  mutex_iD        - ID of the mutex to be acquired
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Acquire a mutex object.
 *
 ******************************************************************************/

acpi_status
acpi_ut_acquire_mutex (
	acpi_mutex_handle               mutex_id)
{
	acpi_status                     status;
	u32                             this_thread_id;


	ACPI_FUNCTION_NAME ("ut_acquire_mutex");


	if (mutex_id > MAX_MUTEX) {
		return (AE_BAD_PARAMETER);
	}

	this_thread_id = acpi_os_get_thread_id ();

#ifdef ACPI_MUTEX_DEBUG
	{
		u32                             i;
		/*
		 * Mutex debug code, for internal debugging only.
		 *
		 * Deadlock prevention.  Check if this thread owns any mutexes of value
		 * greater than or equal to this one.  If so, the thread has violated
		 * the mutex ordering rule.  This indicates a coding error somewhere in
		 * the ACPI subsystem code.
		 */
		for (i = mutex_id; i < MAX_MUTEX; i++) {
			if (acpi_gbl_mutex_info[i].owner_id == this_thread_id) {
				if (i == mutex_id) {
					ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
						"Mutex [%s] already acquired by this thread [%X]\n",
						acpi_ut_get_mutex_name (mutex_id), this_thread_id));

					return (AE_ALREADY_ACQUIRED);
				}

				ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
					"Invalid acquire order: Thread %X owns [%s], wants [%s]\n",
					this_thread_id, acpi_ut_get_mutex_name (i),
					acpi_ut_get_mutex_name (mutex_id)));

				return (AE_ACQUIRE_DEADLOCK);
			}
		}
	}
#endif

	ACPI_DEBUG_PRINT ((ACPI_DB_MUTEX,
		"Thread %X attempting to acquire Mutex [%s]\n",
		this_thread_id, acpi_ut_get_mutex_name (mutex_id)));

	status = acpi_os_wait_semaphore (acpi_gbl_mutex_info[mutex_id].mutex,
			   1, ACPI_WAIT_FOREVER);
	if (ACPI_SUCCESS (status)) {
		ACPI_DEBUG_PRINT ((ACPI_DB_MUTEX, "Thread %X acquired Mutex [%s]\n",
			this_thread_id, acpi_ut_get_mutex_name (mutex_id)));

		acpi_gbl_mutex_info[mutex_id].use_count++;
		acpi_gbl_mutex_info[mutex_id].thread_id = this_thread_id;
	}
	else {
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
			"Thread %X could not acquire Mutex [%s] %s\n",
				this_thread_id, acpi_ut_get_mutex_name (mutex_id),
				acpi_format_exception (status)));
	}

	return (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_release_mutex
 *
 * PARAMETERS:  mutex_iD        - ID of the mutex to be released
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Release a mutex object.
 *
 ******************************************************************************/

acpi_status
acpi_ut_release_mutex (
	acpi_mutex_handle               mutex_id)
{
	acpi_status                     status;
	u32                             this_thread_id;


	ACPI_FUNCTION_NAME ("ut_release_mutex");


	this_thread_id = acpi_os_get_thread_id ();
	ACPI_DEBUG_PRINT ((ACPI_DB_MUTEX,
		"Thread %X releasing Mutex [%s]\n", this_thread_id,
		acpi_ut_get_mutex_name (mutex_id)));

	if (mutex_id > MAX_MUTEX) {
		return (AE_BAD_PARAMETER);
	}

	/*
	 * Mutex must be acquired in order to release it!
	 */
	if (acpi_gbl_mutex_info[mutex_id].thread_id == ACPI_MUTEX_NOT_ACQUIRED) {
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
			"Mutex [%s] is not acquired, cannot release\n",
			acpi_ut_get_mutex_name (mutex_id)));

		return (AE_NOT_ACQUIRED);
	}

#ifdef ACPI_MUTEX_DEBUG
	{
		u32                             i;
		/*
		 * Mutex debug code, for internal debugging only.
		 *
		 * Deadlock prevention.  Check if this thread owns any mutexes of value
		 * greater than this one.  If so, the thread has violated the mutex
		 * ordering rule.  This indicates a coding error somewhere in
		 * the ACPI subsystem code.
		 */
		for (i = mutex_id; i < MAX_MUTEX; i++) {
			if (acpi_gbl_mutex_info[i].owner_id == this_thread_id) {
				if (i == mutex_id) {
					continue;
				}

				ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
					"Invalid release order: owns [%s], releasing [%s]\n",
					acpi_ut_get_mutex_name (i), acpi_ut_get_mutex_name (mutex_id)));

				return (AE_RELEASE_DEADLOCK);
			}
		}
	}
#endif

	/* Mark unlocked FIRST */

	acpi_gbl_mutex_info[mutex_id].thread_id = ACPI_MUTEX_NOT_ACQUIRED;

	status = acpi_os_signal_semaphore (acpi_gbl_mutex_info[mutex_id].mutex, 1);

	if (ACPI_FAILURE (status)) {
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
			"Thread %X could not release Mutex [%s] %s\n",
			this_thread_id, acpi_ut_get_mutex_name (mutex_id),
			acpi_format_exception (status)));
	}
	else {
		ACPI_DEBUG_PRINT ((ACPI_DB_MUTEX, "Thread %X released Mutex [%s]\n",
			this_thread_id, acpi_ut_get_mutex_name (mutex_id)));
	}

	return (status);
}