/*******************************************************************************
   *
   * Module Name: utownerid - Support for Table/Method Owner IDs
   *
   ******************************************************************************/
  
  /*
   * Copyright (C) 2000 - 2013, 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 "acnamesp.h"
  
  #define _COMPONENT          ACPI_UTILITIES
  ACPI_MODULE_NAME("utownerid")
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ut_allocate_owner_id
   *
   * PARAMETERS:  owner_id        - Where the new owner ID is returned
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Allocate a table or method owner ID. The owner ID is used to
   *              track objects created by the table or method, to be deleted
   *              when the method exits or the table is unloaded.
   *
   ******************************************************************************/
  acpi_status acpi_ut_allocate_owner_id(acpi_owner_id * owner_id)
  {
  	u32 i;
  	u32 j;
  	u32 k;
  	acpi_status status;
  
  	ACPI_FUNCTION_TRACE(ut_allocate_owner_id);
  
  	/* Guard against multiple allocations of ID to the same location */
  
  	if (*owner_id) {
  		ACPI_ERROR((AE_INFO, "Owner ID [0x%2.2X] already exists",
  			    *owner_id));
  		return_ACPI_STATUS(AE_ALREADY_EXISTS);
  	}
  
  	/* Mutex for the global ID mask */
  
  	status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
  	if (ACPI_FAILURE(status)) {
  		return_ACPI_STATUS(status);
  	}
  
  	/*
  	 * Find a free owner ID, cycle through all possible IDs on repeated
  	 * allocations. (ACPI_NUM_OWNERID_MASKS + 1) because first index may have
  	 * to be scanned twice.
  	 */
  	for (i = 0, j = acpi_gbl_last_owner_id_index;
  	     i < (ACPI_NUM_OWNERID_MASKS + 1); i++, j++) {
  		if (j >= ACPI_NUM_OWNERID_MASKS) {
  			j = 0;	/* Wraparound to start of mask array */
  		}
  
  		for (k = acpi_gbl_next_owner_id_offset; k < 32; k++) {
  			if (acpi_gbl_owner_id_mask[j] == ACPI_UINT32_MAX) {
  
  				/* There are no free IDs in this mask */
  
  				break;
  			}
  
  			if (!(acpi_gbl_owner_id_mask[j] & (1 << k))) {
  				/*
  				 * Found a free ID. The actual ID is the bit index plus one,
  				 * making zero an invalid Owner ID. Save this as the last ID
  				 * allocated and update the global ID mask.
  				 */
  				acpi_gbl_owner_id_mask[j] |= (1 << k);
  
  				acpi_gbl_last_owner_id_index = (u8)j;
  				acpi_gbl_next_owner_id_offset = (u8)(k + 1);
  
  				/*
  				 * Construct encoded ID from the index and bit position
  				 *
  				 * Note: Last [j].k (bit 255) is never used and is marked
  				 * permanently allocated (prevents +1 overflow)
  				 */
  				*owner_id =
  				    (acpi_owner_id) ((k + 1) + ACPI_MUL_32(j));
  
  				ACPI_DEBUG_PRINT((ACPI_DB_VALUES,
  						  "Allocated OwnerId: %2.2X
  ",
  						  (unsigned int)*owner_id));
  				goto exit;
  			}
  		}
  
  		acpi_gbl_next_owner_id_offset = 0;
  	}
  
  	/*
  	 * All owner_ids have been allocated. This typically should
  	 * not happen since the IDs are reused after deallocation. The IDs are
  	 * allocated upon table load (one per table) and method execution, and
  	 * they are released when a table is unloaded or a method completes
  	 * execution.
  	 *
  	 * If this error happens, there may be very deep nesting of invoked control
  	 * methods, or there may be a bug where the IDs are not released.
  	 */
  	status = AE_OWNER_ID_LIMIT;
  	ACPI_ERROR((AE_INFO,
  		    "Could not allocate new OwnerId (255 max), AE_OWNER_ID_LIMIT"));
  
  exit:
  	(void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
  	return_ACPI_STATUS(status);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ut_release_owner_id
   *
   * PARAMETERS:  owner_id_ptr        - Pointer to a previously allocated owner_ID
   *
   * RETURN:      None. No error is returned because we are either exiting a
   *              control method or unloading a table. Either way, we would
   *              ignore any error anyway.
   *
   * DESCRIPTION: Release a table or method owner ID. Valid IDs are 1 - 255
   *
   ******************************************************************************/
  
  void acpi_ut_release_owner_id(acpi_owner_id * owner_id_ptr)
  {
  	acpi_owner_id owner_id = *owner_id_ptr;
  	acpi_status status;
  	u32 index;
  	u32 bit;
  
  	ACPI_FUNCTION_TRACE_U32(ut_release_owner_id, owner_id);
  
  	/* Always clear the input owner_id (zero is an invalid ID) */
  
  	*owner_id_ptr = 0;
  
  	/* Zero is not a valid owner_ID */
  
  	if (owner_id == 0) {
  		ACPI_ERROR((AE_INFO, "Invalid OwnerId: 0x%2.2X", owner_id));
  		return_VOID;
  	}
  
  	/* Mutex for the global ID mask */
  
  	status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
  	if (ACPI_FAILURE(status)) {
  		return_VOID;
  	}
  
  	/* Normalize the ID to zero */
  
  	owner_id--;
  
  	/* Decode ID to index/offset pair */
  
  	index = ACPI_DIV_32(owner_id);
  	bit = 1 << ACPI_MOD_32(owner_id);
  
  	/* Free the owner ID only if it is valid */
  
  	if (acpi_gbl_owner_id_mask[index] & bit) {
  		acpi_gbl_owner_id_mask[index] ^= bit;
  	} else {
  		ACPI_ERROR((AE_INFO,
  			    "Release of non-allocated OwnerId: 0x%2.2X",
  			    owner_id + 1));
  	}
  
  	(void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
  	return_VOID;
  }