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kernel/linux-rt-4.4.41/drivers/acpi/acpica/tbfadt.c 23 KB
5113f6f70   김현기   kernel add
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  /******************************************************************************
   *
   * Module Name: tbfadt   - FADT table utilities
   *
   *****************************************************************************/
  
  /*
   * 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 "actables.h"
  
  #define _COMPONENT          ACPI_TABLES
  ACPI_MODULE_NAME("tbfadt")
  
  /* Local prototypes */
  static void
  acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
  			     u8 space_id,
  			     u8 byte_width,
  			     u64 address, char *register_name, u8 flags);
  
  static void acpi_tb_convert_fadt(void);
  
  static void acpi_tb_setup_fadt_registers(void);
  
  static u64
  acpi_tb_select_address(char *register_name, u32 address32, u64 address64);
  
  /* Table for conversion of FADT to common internal format and FADT validation */
  
  typedef struct acpi_fadt_info {
  	char *name;
  	u16 address64;
  	u16 address32;
  	u16 length;
  	u8 default_length;
  	u8 flags;
  
  } acpi_fadt_info;
  
  #define ACPI_FADT_OPTIONAL          0
  #define ACPI_FADT_REQUIRED          1
  #define ACPI_FADT_SEPARATE_LENGTH   2
  #define ACPI_FADT_GPE_REGISTER      4
  
  static struct acpi_fadt_info fadt_info_table[] = {
  	{"Pm1aEventBlock",
  	 ACPI_FADT_OFFSET(xpm1a_event_block),
  	 ACPI_FADT_OFFSET(pm1a_event_block),
  	 ACPI_FADT_OFFSET(pm1_event_length),
  	 ACPI_PM1_REGISTER_WIDTH * 2,	/* Enable + Status register */
  	 ACPI_FADT_REQUIRED},
  
  	{"Pm1bEventBlock",
  	 ACPI_FADT_OFFSET(xpm1b_event_block),
  	 ACPI_FADT_OFFSET(pm1b_event_block),
  	 ACPI_FADT_OFFSET(pm1_event_length),
  	 ACPI_PM1_REGISTER_WIDTH * 2,	/* Enable + Status register */
  	 ACPI_FADT_OPTIONAL},
  
  	{"Pm1aControlBlock",
  	 ACPI_FADT_OFFSET(xpm1a_control_block),
  	 ACPI_FADT_OFFSET(pm1a_control_block),
  	 ACPI_FADT_OFFSET(pm1_control_length),
  	 ACPI_PM1_REGISTER_WIDTH,
  	 ACPI_FADT_REQUIRED},
  
  	{"Pm1bControlBlock",
  	 ACPI_FADT_OFFSET(xpm1b_control_block),
  	 ACPI_FADT_OFFSET(pm1b_control_block),
  	 ACPI_FADT_OFFSET(pm1_control_length),
  	 ACPI_PM1_REGISTER_WIDTH,
  	 ACPI_FADT_OPTIONAL},
  
  	{"Pm2ControlBlock",
  	 ACPI_FADT_OFFSET(xpm2_control_block),
  	 ACPI_FADT_OFFSET(pm2_control_block),
  	 ACPI_FADT_OFFSET(pm2_control_length),
  	 ACPI_PM2_REGISTER_WIDTH,
  	 ACPI_FADT_SEPARATE_LENGTH},
  
  	{"PmTimerBlock",
  	 ACPI_FADT_OFFSET(xpm_timer_block),
  	 ACPI_FADT_OFFSET(pm_timer_block),
  	 ACPI_FADT_OFFSET(pm_timer_length),
  	 ACPI_PM_TIMER_WIDTH,
  	 ACPI_FADT_SEPARATE_LENGTH},	/* ACPI 5.0A: Timer is optional */
  
  	{"Gpe0Block",
  	 ACPI_FADT_OFFSET(xgpe0_block),
  	 ACPI_FADT_OFFSET(gpe0_block),
  	 ACPI_FADT_OFFSET(gpe0_block_length),
  	 0,
  	 ACPI_FADT_SEPARATE_LENGTH | ACPI_FADT_GPE_REGISTER},
  
  	{"Gpe1Block",
  	 ACPI_FADT_OFFSET(xgpe1_block),
  	 ACPI_FADT_OFFSET(gpe1_block),
  	 ACPI_FADT_OFFSET(gpe1_block_length),
  	 0,
  	 ACPI_FADT_SEPARATE_LENGTH | ACPI_FADT_GPE_REGISTER}
  };
  
  #define ACPI_FADT_INFO_ENTRIES \
  			(sizeof (fadt_info_table) / sizeof (struct acpi_fadt_info))
  
  /* Table used to split Event Blocks into separate status/enable registers */
  
  typedef struct acpi_fadt_pm_info {
  	struct acpi_generic_address *target;
  	u16 source;
  	u8 register_num;
  
  } acpi_fadt_pm_info;
  
  static struct acpi_fadt_pm_info fadt_pm_info_table[] = {
  	{&acpi_gbl_xpm1a_status,
  	 ACPI_FADT_OFFSET(xpm1a_event_block),
  	 0},
  
  	{&acpi_gbl_xpm1a_enable,
  	 ACPI_FADT_OFFSET(xpm1a_event_block),
  	 1},
  
  	{&acpi_gbl_xpm1b_status,
  	 ACPI_FADT_OFFSET(xpm1b_event_block),
  	 0},
  
  	{&acpi_gbl_xpm1b_enable,
  	 ACPI_FADT_OFFSET(xpm1b_event_block),
  	 1}
  };
  
  #define ACPI_FADT_PM_INFO_ENTRIES \
  			(sizeof (fadt_pm_info_table) / sizeof (struct acpi_fadt_pm_info))
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_tb_init_generic_address
   *
   * PARAMETERS:  generic_address     - GAS struct to be initialized
   *              space_id            - ACPI Space ID for this register
   *              byte_width          - Width of this register
   *              address             - Address of the register
   *              register_name       - ASCII name of the ACPI register
   *
   * RETURN:      None
   *
   * DESCRIPTION: Initialize a Generic Address Structure (GAS)
   *              See the ACPI specification for a full description and
   *              definition of this structure.
   *
   ******************************************************************************/
  
  static void
  acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
  			     u8 space_id,
  			     u8 byte_width,
  			     u64 address, char *register_name, u8 flags)
  {
  	u8 bit_width;
  
  	/*
  	 * Bit width field in the GAS is only one byte long, 255 max.
  	 * Check for bit_width overflow in GAS.
  	 */
  	bit_width = (u8)(byte_width * 8);
  	if (byte_width > 31) {	/* (31*8)=248, (32*8)=256 */
  		/*
  		 * No error for GPE blocks, because we do not use the bit_width
  		 * for GPEs, the legacy length (byte_width) is used instead to
  		 * allow for a large number of GPEs.
  		 */
  		if (!(flags & ACPI_FADT_GPE_REGISTER)) {
  			ACPI_ERROR((AE_INFO,
  				    "%s - 32-bit FADT register is too long (%u bytes, %u bits) "
  				    "to convert to GAS struct - 255 bits max, truncating",
  				    register_name, byte_width,
  				    (byte_width * 8)));
  		}
  
  		bit_width = 255;
  	}
  
  	/*
  	 * The 64-bit Address field is non-aligned in the byte packed
  	 * GAS struct.
  	 */
  	ACPI_MOVE_64_TO_64(&generic_address->address, &address);
  
  	/* All other fields are byte-wide */
  
  	generic_address->space_id = space_id;
  	generic_address->bit_width = bit_width;
  	generic_address->bit_offset = 0;
  	generic_address->access_width = 0;	/* Access width ANY */
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_tb_select_address
   *
   * PARAMETERS:  register_name       - ASCII name of the ACPI register
   *              address32           - 32-bit address of the register
   *              address64           - 64-bit address of the register
   *
   * RETURN:      The resolved 64-bit address
   *
   * DESCRIPTION: Select between 32-bit and 64-bit versions of addresses within
   *              the FADT. Used for the FACS and DSDT addresses.
   *
   * NOTES:
   *
   * Check for FACS and DSDT address mismatches. An address mismatch between
   * the 32-bit and 64-bit address fields (FIRMWARE_CTRL/X_FIRMWARE_CTRL and
   * DSDT/X_DSDT) could be a corrupted address field or it might indicate
   * the presence of two FACS or two DSDT tables.
   *
   * November 2013:
   * By default, as per the ACPICA specification, a valid 64-bit address is
   * used regardless of the value of the 32-bit address. However, this
   * behavior can be overridden via the acpi_gbl_use32_bit_fadt_addresses flag.
   *
   ******************************************************************************/
  
  static u64
  acpi_tb_select_address(char *register_name, u32 address32, u64 address64)
  {
  
  	if (!address64) {
  
  		/* 64-bit address is zero, use 32-bit address */
  
  		return ((u64)address32);
  	}
  
  	if (address32 && (address64 != (u64)address32)) {
  
  		/* Address mismatch between 32-bit and 64-bit versions */
  
  		ACPI_BIOS_WARNING((AE_INFO,
  				   "32/64X %s address mismatch in FADT: "
  				   "0x%8.8X/0x%8.8X%8.8X, using %u-bit address",
  				   register_name, address32,
  				   ACPI_FORMAT_UINT64(address64),
  				   acpi_gbl_use32_bit_fadt_addresses ? 32 :
  				   64));
  
  		/* 32-bit address override */
  
  		if (acpi_gbl_use32_bit_fadt_addresses) {
  			return ((u64)address32);
  		}
  	}
  
  	/* Default is to use the 64-bit address */
  
  	return (address64);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_tb_parse_fadt
   *
   * PARAMETERS:  None
   *
   * RETURN:      None
   *
   * DESCRIPTION: Initialize the FADT, DSDT and FACS tables
   *              (FADT contains the addresses of the DSDT and FACS)
   *
   ******************************************************************************/
  
  void acpi_tb_parse_fadt(void)
  {
  	u32 length;
  	struct acpi_table_header *table;
  
  	/*
  	 * The FADT has multiple versions with different lengths,
  	 * and it contains pointers to both the DSDT and FACS tables.
  	 *
  	 * Get a local copy of the FADT and convert it to a common format
  	 * Map entire FADT, assumed to be smaller than one page.
  	 */
  	length = acpi_gbl_root_table_list.tables[acpi_gbl_fadt_index].length;
  
  	table =
  	    acpi_os_map_memory(acpi_gbl_root_table_list.
  			       tables[acpi_gbl_fadt_index].address, length);
  	if (!table) {
  		return;
  	}
  
  	/*
  	 * Validate the FADT checksum before we copy the table. Ignore
  	 * checksum error as we want to try to get the DSDT and FACS.
  	 */
  	(void)acpi_tb_verify_checksum(table, length);
  
  	/* Create a local copy of the FADT in common ACPI 2.0+ format */
  
  	acpi_tb_create_local_fadt(table, length);
  
  	/* All done with the real FADT, unmap it */
  
  	acpi_os_unmap_memory(table, length);
  
  	/* Obtain the DSDT and FACS tables via their addresses within the FADT */
  
  	acpi_tb_install_fixed_table((acpi_physical_address) acpi_gbl_FADT.Xdsdt,
  				    ACPI_SIG_DSDT, &acpi_gbl_dsdt_index);
  
  	/* If Hardware Reduced flag is set, there is no FACS */
  
  	if (!acpi_gbl_reduced_hardware) {
  		if (acpi_gbl_FADT.facs) {
  			acpi_tb_install_fixed_table((acpi_physical_address)
  						    acpi_gbl_FADT.facs,
  						    ACPI_SIG_FACS,
  						    &acpi_gbl_facs_index);
  		}
  		if (acpi_gbl_FADT.Xfacs) {
  			acpi_tb_install_fixed_table((acpi_physical_address)
  						    acpi_gbl_FADT.Xfacs,
  						    ACPI_SIG_FACS,
  						    &acpi_gbl_xfacs_index);
  		}
  	}
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_tb_create_local_fadt
   *
   * PARAMETERS:  table               - Pointer to BIOS FADT
   *              length              - Length of the table
   *
   * RETURN:      None
   *
   * DESCRIPTION: Get a local copy of the FADT and convert it to a common format.
   *              Performs validation on some important FADT fields.
   *
   * NOTE:        We create a local copy of the FADT regardless of the version.
   *
   ******************************************************************************/
  
  void acpi_tb_create_local_fadt(struct acpi_table_header *table, u32 length)
  {
  	/*
  	 * Check if the FADT is larger than the largest table that we expect
  	 * (the ACPI 5.0 version). If so, truncate the table, and issue
  	 * a warning.
  	 */
  	if (length > sizeof(struct acpi_table_fadt)) {
  		ACPI_BIOS_WARNING((AE_INFO,
  				   "FADT (revision %u) is longer than ACPI 5.0 version, "
  				   "truncating length %u to %u",
  				   table->revision, length,
  				   (u32)sizeof(struct acpi_table_fadt)));
  	}
  
  	/* Clear the entire local FADT */
  
  	memset(&acpi_gbl_FADT, 0, sizeof(struct acpi_table_fadt));
  
  	/* Copy the original FADT, up to sizeof (struct acpi_table_fadt) */
  
  	memcpy(&acpi_gbl_FADT, table,
  	       ACPI_MIN(length, sizeof(struct acpi_table_fadt)));
  
  	/* Take a copy of the Hardware Reduced flag */
  
  	acpi_gbl_reduced_hardware = FALSE;
  	if (acpi_gbl_FADT.flags & ACPI_FADT_HW_REDUCED) {
  		acpi_gbl_reduced_hardware = TRUE;
  	}
  
  	/* Convert the local copy of the FADT to the common internal format */
  
  	acpi_tb_convert_fadt();
  
  	/* Initialize the global ACPI register structures */
  
  	acpi_tb_setup_fadt_registers();
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_tb_convert_fadt
   *
   * PARAMETERS:  none - acpi_gbl_FADT is used.
   *
   * RETURN:      None
   *
   * DESCRIPTION: Converts all versions of the FADT to a common internal format.
   *              Expand 32-bit addresses to 64-bit as necessary. Also validate
   *              important fields within the FADT.
   *
   * NOTE:        acpi_gbl_FADT must be of size (struct acpi_table_fadt), and must
   *              contain a copy of the actual BIOS-provided FADT.
   *
   * Notes on 64-bit register addresses:
   *
   * After this FADT conversion, later ACPICA code will only use the 64-bit "X"
   * fields of the FADT for all ACPI register addresses.
   *
   * The 64-bit X fields are optional extensions to the original 32-bit FADT
   * V1.0 fields. Even if they are present in the FADT, they are optional and
   * are unused if the BIOS sets them to zero. Therefore, we must copy/expand
   * 32-bit V1.0 fields to the 64-bit X fields if the the 64-bit X field is
   * originally zero.
   *
   * For ACPI 1.0 FADTs (that contain no 64-bit addresses), all 32-bit address
   * fields are expanded to the corresponding 64-bit X fields in the internal
   * common FADT.
   *
   * For ACPI 2.0+ FADTs, all valid (non-zero) 32-bit address fields are expanded
   * to the corresponding 64-bit X fields, if the 64-bit field is originally
   * zero. Adhering to the ACPI specification, we completely ignore the 32-bit
   * field if the 64-bit field is valid, regardless of whether the host OS is
   * 32-bit or 64-bit.
   *
   * Possible additional checks:
   *  (acpi_gbl_FADT.pm1_event_length >= 4)
   *  (acpi_gbl_FADT.pm1_control_length >= 2)
   *  (acpi_gbl_FADT.pm_timer_length >= 4)
   *  Gpe block lengths must be multiple of 2
   *
   ******************************************************************************/
  
  static void acpi_tb_convert_fadt(void)
  {
  	char *name;
  	struct acpi_generic_address *address64;
  	u32 address32;
  	u8 length;
  	u8 flags;
  	u32 i;
  
  	/*
  	 * For ACPI 1.0 FADTs (revision 1 or 2), ensure that reserved fields which
  	 * should be zero are indeed zero. This will workaround BIOSs that
  	 * inadvertently place values in these fields.
  	 *
  	 * The ACPI 1.0 reserved fields that will be zeroed are the bytes located
  	 * at offset 45, 55, 95, and the word located at offset 109, 110.
  	 *
  	 * Note: The FADT revision value is unreliable. Only the length can be
  	 * trusted.
  	 */
  	if (acpi_gbl_FADT.header.length <= ACPI_FADT_V2_SIZE) {
  		acpi_gbl_FADT.preferred_profile = 0;
  		acpi_gbl_FADT.pstate_control = 0;
  		acpi_gbl_FADT.cst_control = 0;
  		acpi_gbl_FADT.boot_flags = 0;
  	}
  
  	/*
  	 * Now we can update the local FADT length to the length of the
  	 * current FADT version as defined by the ACPI specification.
  	 * Thus, we will have a common FADT internally.
  	 */
  	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
  
  	/*
  	 * Expand the 32-bit DSDT addresses to 64-bit as necessary.
  	 * Later ACPICA code will always use the X 64-bit field.
  	 */
  	acpi_gbl_FADT.Xdsdt = acpi_tb_select_address("DSDT",
  						     acpi_gbl_FADT.dsdt,
  						     acpi_gbl_FADT.Xdsdt);
  
  	/* If Hardware Reduced flag is set, we are all done */
  
  	if (acpi_gbl_reduced_hardware) {
  		return;
  	}
  
  	/* Examine all of the 64-bit extended address fields (X fields) */
  
  	for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
  		/*
  		 * Get the 32-bit and 64-bit addresses, as well as the register
  		 * length and register name.
  		 */
  		address32 = *ACPI_ADD_PTR(u32,
  					  &acpi_gbl_FADT,
  					  fadt_info_table[i].address32);
  
  		address64 = ACPI_ADD_PTR(struct acpi_generic_address,
  					 &acpi_gbl_FADT,
  					 fadt_info_table[i].address64);
  
  		length = *ACPI_ADD_PTR(u8,
  				       &acpi_gbl_FADT,
  				       fadt_info_table[i].length);
  
  		name = fadt_info_table[i].name;
  		flags = fadt_info_table[i].flags;
  
  		/*
  		 * Expand the ACPI 1.0 32-bit addresses to the ACPI 2.0 64-bit "X"
  		 * generic address structures as necessary. Later code will always use
  		 * the 64-bit address structures.
  		 *
  		 * November 2013:
  		 * Now always use the 64-bit address if it is valid (non-zero), in
  		 * accordance with the ACPI specification which states that a 64-bit
  		 * address supersedes the 32-bit version. This behavior can be
  		 * overridden by the acpi_gbl_use32_bit_fadt_addresses flag.
  		 *
  		 * During 64-bit address construction and verification,
  		 * these cases are handled:
  		 *
  		 * Address32 zero, Address64 [don't care]   - Use Address64
  		 *
  		 * Address32 non-zero, Address64 zero       - Copy/use Address32
  		 * Address32 non-zero == Address64 non-zero - Use Address64
  		 * Address32 non-zero != Address64 non-zero - Warning, use Address64
  		 *
  		 * Override: if acpi_gbl_use32_bit_fadt_addresses is TRUE, and:
  		 * Address32 non-zero != Address64 non-zero - Warning, copy/use Address32
  		 *
  		 * Note: space_id is always I/O for 32-bit legacy address fields
  		 */
  		if (address32) {
  			if (!address64->address) {
  
  				/* 64-bit address is zero, use 32-bit address */
  
  				acpi_tb_init_generic_address(address64,
  							     ACPI_ADR_SPACE_SYSTEM_IO,
  							     *ACPI_ADD_PTR(u8,
  									   &acpi_gbl_FADT,
  									   fadt_info_table
  									   [i].
  									   length),
  							     (u64)address32,
  							     name, flags);
  			} else if (address64->address != (u64)address32) {
  
  				/* Address mismatch */
  
  				ACPI_BIOS_WARNING((AE_INFO,
  						   "32/64X address mismatch in FADT/%s: "
  						   "0x%8.8X/0x%8.8X%8.8X, using %u-bit address",
  						   name, address32,
  						   ACPI_FORMAT_UINT64
  						   (address64->address),
  						   acpi_gbl_use32_bit_fadt_addresses
  						   ? 32 : 64));
  
  				if (acpi_gbl_use32_bit_fadt_addresses) {
  
  					/* 32-bit address override */
  
  					acpi_tb_init_generic_address(address64,
  								     ACPI_ADR_SPACE_SYSTEM_IO,
  								     *ACPI_ADD_PTR
  								     (u8,
  								      &acpi_gbl_FADT,
  								      fadt_info_table
  								      [i].
  								      length),
  								     (u64)
  								     address32,
  								     name,
  								     flags);
  				}
  			}
  		}
  
  		/*
  		 * For each extended field, check for length mismatch between the
  		 * legacy length field and the corresponding 64-bit X length field.
  		 * Note: If the legacy length field is > 0xFF bits, ignore this
  		 * check. (GPE registers can be larger than the 64-bit GAS structure
  		 * can accomodate, 0xFF bits).
  		 */
  		if (address64->address &&
  		    (ACPI_MUL_8(length) <= ACPI_UINT8_MAX) &&
  		    (address64->bit_width != ACPI_MUL_8(length))) {
  			ACPI_BIOS_WARNING((AE_INFO,
  					   "32/64X length mismatch in FADT/%s: %u/%u",
  					   name, ACPI_MUL_8(length),
  					   address64->bit_width));
  		}
  
  		if (fadt_info_table[i].flags & ACPI_FADT_REQUIRED) {
  			/*
  			 * Field is required (Pm1a_event, Pm1a_control).
  			 * Both the address and length must be non-zero.
  			 */
  			if (!address64->address || !length) {
  				ACPI_BIOS_ERROR((AE_INFO,
  						 "Required FADT field %s has zero address and/or length: "
  						 "0x%8.8X%8.8X/0x%X",
  						 name,
  						 ACPI_FORMAT_UINT64(address64->
  								    address),
  						 length));
  			}
  		} else if (fadt_info_table[i].flags & ACPI_FADT_SEPARATE_LENGTH) {
  			/*
  			 * Field is optional (Pm2_control, GPE0, GPE1) AND has its own
  			 * length field. If present, both the address and length must
  			 * be valid.
  			 */
  			if ((address64->address && !length) ||
  			    (!address64->address && length)) {
  				ACPI_BIOS_WARNING((AE_INFO,
  						   "Optional FADT field %s has zero address or length: "
  						   "0x%8.8X%8.8X/0x%X",
  						   name,
  						   ACPI_FORMAT_UINT64
  						   (address64->address),
  						   length));
  			}
  		}
  	}
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_tb_setup_fadt_registers
   *
   * PARAMETERS:  None, uses acpi_gbl_FADT.
   *
   * RETURN:      None
   *
   * DESCRIPTION: Initialize global ACPI PM1 register definitions. Optionally,
   *              force FADT register definitions to their default lengths.
   *
   ******************************************************************************/
  
  static void acpi_tb_setup_fadt_registers(void)
  {
  	struct acpi_generic_address *target64;
  	struct acpi_generic_address *source64;
  	u8 pm1_register_byte_width;
  	u32 i;
  
  	/*
  	 * Optionally check all register lengths against the default values and
  	 * update them if they are incorrect.
  	 */
  	if (acpi_gbl_use_default_register_widths) {
  		for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
  			target64 =
  			    ACPI_ADD_PTR(struct acpi_generic_address,
  					 &acpi_gbl_FADT,
  					 fadt_info_table[i].address64);
  
  			/*
  			 * If a valid register (Address != 0) and the (default_length > 0)
  			 * (Not a GPE register), then check the width against the default.
  			 */
  			if ((target64->address) &&
  			    (fadt_info_table[i].default_length > 0) &&
  			    (fadt_info_table[i].default_length !=
  			     target64->bit_width)) {
  				ACPI_BIOS_WARNING((AE_INFO,
  						   "Invalid length for FADT/%s: %u, using default %u",
  						   fadt_info_table[i].name,
  						   target64->bit_width,
  						   fadt_info_table[i].
  						   default_length));
  
  				/* Incorrect size, set width to the default */
  
  				target64->bit_width =
  				    fadt_info_table[i].default_length;
  			}
  		}
  	}
  
  	/*
  	 * Get the length of the individual PM1 registers (enable and status).
  	 * Each register is defined to be (event block length / 2). Extra divide
  	 * by 8 converts bits to bytes.
  	 */
  	pm1_register_byte_width = (u8)
  	    ACPI_DIV_16(acpi_gbl_FADT.xpm1a_event_block.bit_width);
  
  	/*
  	 * Calculate separate GAS structs for the PM1x (A/B) Status and Enable
  	 * registers. These addresses do not appear (directly) in the FADT, so it
  	 * is useful to pre-calculate them from the PM1 Event Block definitions.
  	 *
  	 * The PM event blocks are split into two register blocks, first is the
  	 * PM Status Register block, followed immediately by the PM Enable
  	 * Register block. Each is of length (pm1_event_length/2)
  	 *
  	 * Note: The PM1A event block is required by the ACPI specification.
  	 * However, the PM1B event block is optional and is rarely, if ever,
  	 * used.
  	 */
  
  	for (i = 0; i < ACPI_FADT_PM_INFO_ENTRIES; i++) {
  		source64 =
  		    ACPI_ADD_PTR(struct acpi_generic_address, &acpi_gbl_FADT,
  				 fadt_pm_info_table[i].source);
  
  		if (source64->address) {
  			acpi_tb_init_generic_address(fadt_pm_info_table[i].
  						     target, source64->space_id,
  						     pm1_register_byte_width,
  						     source64->address +
  						     (fadt_pm_info_table[i].
  						      register_num *
  						      pm1_register_byte_width),
  						     "PmRegisters", 0);
  		}
  	}
  }