// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: tbfadt   - FADT table utilities
 *
 * Copyright (C) 2000 - 2021, Intel Corp.
 *
 *****************************************************************************/

#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, const 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 {
        const 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, const 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;
        struct acpi_table_desc *fadt_desc;
        acpi_status status;

        /*
         * 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.
         */
        fadt_desc = &acpi_gbl_root_table_list.tables[acpi_gbl_fadt_index];
        status = acpi_tb_get_table(fadt_desc, &table);
        if (ACPI_FAILURE(status)) {
                return;
        }
        length = fadt_desc->length;

        /*
         * 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_tb_put_table(fadt_desc);

        /* Obtain the DSDT and FACS tables via their addresses within the FADT */

        acpi_tb_install_standard_table((acpi_physical_address)acpi_gbl_FADT.
                                       Xdsdt,
                                       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
                                       FALSE, TRUE, &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_standard_table((acpi_physical_address)
                                                       acpi_gbl_FADT.facs,
                                                       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
                                                       FALSE, TRUE,
                                                       &acpi_gbl_facs_index);
                }
                if (acpi_gbl_FADT.Xfacs) {
                        acpi_tb_install_standard_table((acpi_physical_address)
                                                       acpi_gbl_FADT.Xfacs,
                                                       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
                                                       FALSE, TRUE,
                                                       &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
         * (typically the current ACPI specification 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 %s length, "
                                   "truncating length %u to %u",
                                   table->revision, ACPI_FADT_CONFORMANCE,
                                   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 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)
{
        const 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
                 *
                 * No override: if acpi_gbl_use32_bit_fadt_addresses is FALSE, and:
                 * 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 zero       - Copy/use Address32
                 * Address32 non-zero == Address64 non-zero - Copy/use Address32
                 * 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) {
                                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));
                                }

                                /*
                                 * 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 accommodate, 0xFF bits).
                                 */
                                if ((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));
                                }
                        }

                        /*
                         * Hardware register access code always uses the 64-bit fields.
                         * So if the 64-bit field is zero or is to be overridden,
                         * initialize it with the 32-bit fields.
                         * Note that when the 32-bit address favor is specified, the
                         * 64-bit fields are always re-initialized so that
                         * access_size/bit_width/bit_offset fields can be correctly
                         * configured to the values to trigger a 32-bit compatible
                         * access mode in the hardware register access code.
                         */
                        if (!address64->address
                            || acpi_gbl_use32_bit_fadt_addresses) {
                                acpi_tb_init_generic_address(address64,
                                                             ACPI_ADR_SPACE_SYSTEM_IO,
                                                             length,
                                                             (u64)address32,
                                                             name, flags);
                        }
                }

                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 valid %s but zero %s: "
                                                   "0x%8.8X%8.8X/0x%X", name,
                                                   (length ? "Length" :
                                                    "Address"),
                                                   (length ? "Address" :
                                                    "Length"),
                                                   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);
                }
        }
}