text: 
  /******************************************************************************
   *
   * Module Name: exsystem - Interface to OS services
   *
   *****************************************************************************/
  
  /*
   * Copyright (C) 2000 - 2012, 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 "acinterp.h"
  
  #define _COMPONENT          ACPI_EXECUTER
  ACPI_MODULE_NAME("exsystem")
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ex_system_wait_semaphore
   *
   * PARAMETERS:  semaphore       - Semaphore to wait on
   *              timeout         - Max time to wait
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Implements a semaphore wait with a check to see if the
   *              semaphore is available immediately.  If it is not, the
   *              interpreter is released before waiting.
   *
   ******************************************************************************/
  acpi_status acpi_ex_system_wait_semaphore(acpi_semaphore semaphore, u16 timeout)
  {
  	acpi_status status;
  
  	ACPI_FUNCTION_TRACE(ex_system_wait_semaphore);
  
  	status = acpi_os_wait_semaphore(semaphore, 1, ACPI_DO_NOT_WAIT);
  	if (ACPI_SUCCESS(status)) {
  		return_ACPI_STATUS(status);
  	}
  
  	if (status == AE_TIME) {
  
  		/* We must wait, so unlock the interpreter */
  
  		acpi_ex_relinquish_interpreter();
  
  		status = acpi_os_wait_semaphore(semaphore, 1, timeout);
  
  		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
  				  "*** Thread awake after blocking, %s\n",
  				  acpi_format_exception(status)));
  
  		/* Reacquire the interpreter */
  
  		acpi_ex_reacquire_interpreter();
  	}
  
  	return_ACPI_STATUS(status);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ex_system_wait_mutex
   *
   * PARAMETERS:  mutex           - Mutex to wait on
   *              timeout         - Max time to wait
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Implements a mutex wait with a check to see if the
   *              mutex is available immediately.  If it is not, the
   *              interpreter is released before waiting.
   *
   ******************************************************************************/
  
  acpi_status acpi_ex_system_wait_mutex(acpi_mutex mutex, u16 timeout)
  {
  	acpi_status status;
  
  	ACPI_FUNCTION_TRACE(ex_system_wait_mutex);
  
  	status = acpi_os_acquire_mutex(mutex, ACPI_DO_NOT_WAIT);
  	if (ACPI_SUCCESS(status)) {
  		return_ACPI_STATUS(status);
  	}
  
  	if (status == AE_TIME) {
  
  		/* We must wait, so unlock the interpreter */
  
  		acpi_ex_relinquish_interpreter();
  
  		status = acpi_os_acquire_mutex(mutex, timeout);
  
  		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
  				  "*** Thread awake after blocking, %s\n",
  				  acpi_format_exception(status)));
  
  		/* Reacquire the interpreter */
  
  		acpi_ex_reacquire_interpreter();
  	}
  
  	return_ACPI_STATUS(status);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ex_system_do_stall
   *
   * PARAMETERS:  how_long        - The amount of time to stall,
   *                                in microseconds
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Suspend running thread for specified amount of time.
   *              Note: ACPI specification requires that Stall() does not
   *              relinquish the processor, and delays longer than 100 usec
   *              should use Sleep() instead.  We allow stalls up to 255 usec
   *              for compatibility with other interpreters and existing BIOSs.
   *
   ******************************************************************************/
  
  acpi_status acpi_ex_system_do_stall(u32 how_long)
  {
  	acpi_status status = AE_OK;
  
  	ACPI_FUNCTION_ENTRY();
  
  	if (how_long > 255) {	/* 255 microseconds */
  		/*
  		 * Longer than 255 usec, this is an error
  		 *
  		 * (ACPI specifies 100 usec as max, but this gives some slack in
  		 * order to support existing BIOSs)
  		 */
  		ACPI_ERROR((AE_INFO, "Time parameter is too large (%u)",
  			    how_long));
  		status = AE_AML_OPERAND_VALUE;
  	} else {
  		acpi_os_stall(how_long);
  	}
  
  	return (status);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ex_system_do_sleep
   *
   * PARAMETERS:  how_long        - The amount of time to sleep,
   *                                in milliseconds
   *
   * RETURN:      None
   *
   * DESCRIPTION: Sleep the running thread for specified amount of time.
   *
   ******************************************************************************/
  
  acpi_status acpi_ex_system_do_sleep(u64 how_long)
  {
  	ACPI_FUNCTION_ENTRY();
  
  	/* Since this thread will sleep, we must release the interpreter */
  
  	acpi_ex_relinquish_interpreter();
  
  	/*
  	 * For compatibility with other ACPI implementations and to prevent
  	 * accidental deep sleeps, limit the sleep time to something reasonable.
  	 */
  	if (how_long > ACPI_MAX_SLEEP) {
  		how_long = ACPI_MAX_SLEEP;
  	}
  
  	acpi_os_sleep(how_long);
  
  	/* And now we must get the interpreter again */
  
  	acpi_ex_reacquire_interpreter();
  	return (AE_OK);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ex_system_signal_event
   *
   * PARAMETERS:  obj_desc        - The object descriptor for this op
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Provides an access point to perform synchronization operations
   *              within the AML.
   *
   ******************************************************************************/
  
  acpi_status acpi_ex_system_signal_event(union acpi_operand_object * obj_desc)
  {
  	acpi_status status = AE_OK;
  
  	ACPI_FUNCTION_TRACE(ex_system_signal_event);
  
  	if (obj_desc) {
  		status =
  		    acpi_os_signal_semaphore(obj_desc->event.os_semaphore, 1);
  	}
  
  	return_ACPI_STATUS(status);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ex_system_wait_event
   *
   * PARAMETERS:  time_desc       - The 'time to delay' object descriptor
   *              obj_desc        - The object descriptor for this op
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Provides an access point to perform synchronization operations
   *              within the AML.  This operation is a request to wait for an
   *              event.
   *
   ******************************************************************************/
  
  acpi_status
  acpi_ex_system_wait_event(union acpi_operand_object *time_desc,
  			  union acpi_operand_object *obj_desc)
  {
  	acpi_status status = AE_OK;
  
  	ACPI_FUNCTION_TRACE(ex_system_wait_event);
  
  	if (obj_desc) {
  		status =
  		    acpi_ex_system_wait_semaphore(obj_desc->event.os_semaphore,
  						  (u16) time_desc->integer.
  						  value);
  	}
  
  	return_ACPI_STATUS(status);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ex_system_reset_event
   *
   * PARAMETERS:  obj_desc        - The object descriptor for this op
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Reset an event to a known state.
   *
   ******************************************************************************/
  
  acpi_status acpi_ex_system_reset_event(union acpi_operand_object *obj_desc)
  {
  	acpi_status status = AE_OK;
  	acpi_semaphore temp_semaphore;
  
  	ACPI_FUNCTION_ENTRY();
  
  	/*
  	 * We are going to simply delete the existing semaphore and
  	 * create a new one!
  	 */
  	status =
  	    acpi_os_create_semaphore(ACPI_NO_UNIT_LIMIT, 0, &temp_semaphore);
  	if (ACPI_SUCCESS(status)) {
  		(void)acpi_os_delete_semaphore(obj_desc->event.os_semaphore);
  		obj_desc->event.os_semaphore = temp_semaphore;
  	}
  
  	return (status);
  }
  