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hwregs.c

/*******************************************************************************
 *
 * Module Name: hwregs - Read/write access functions for the various ACPI
 *                       control and status registers.
 *
 ******************************************************************************/

/*
 * Copyright (C) 2000 - 2007, 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>
#include <acpi/acnamesp.h>
#include <acpi/acevents.h>

#define _COMPONENT          ACPI_HARDWARE
ACPI_MODULE_NAME("hwregs")

/*******************************************************************************
 *
 * FUNCTION:    acpi_hw_clear_acpi_status
 *
 * PARAMETERS:  None
 *
 * RETURN:      None
 *
 * DESCRIPTION: Clears all fixed and general purpose status bits
 *              THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
 *
 ******************************************************************************/
acpi_status acpi_hw_clear_acpi_status(void)
{
      acpi_status status;
      acpi_cpu_flags lock_flags = 0;

      ACPI_FUNCTION_TRACE(hw_clear_acpi_status);

      ACPI_DEBUG_PRINT((ACPI_DB_IO, "About to write %04X to %04X\n",
                    ACPI_BITMASK_ALL_FIXED_STATUS,
                    (u16) acpi_gbl_FADT.xpm1a_event_block.address));

      lock_flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);

      status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
                              ACPI_BITMASK_ALL_FIXED_STATUS);
      if (ACPI_FAILURE(status)) {
            goto unlock_and_exit;
      }

      /* Clear the fixed events */

      if (acpi_gbl_FADT.xpm1b_event_block.address) {
            status =
                acpi_hw_low_level_write(16, ACPI_BITMASK_ALL_FIXED_STATUS,
                                  &acpi_gbl_FADT.xpm1b_event_block);
            if (ACPI_FAILURE(status)) {
                  goto unlock_and_exit;
            }
      }

      /* Clear the GPE Bits in all GPE registers in all GPE blocks */

      status = acpi_ev_walk_gpe_list(acpi_hw_clear_gpe_block);

      unlock_and_exit:
      acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
      return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_get_sleep_type_data
 *
 * PARAMETERS:  sleep_state         - Numeric sleep state
 *              *sleep_type_a        - Where SLP_TYPa is returned
 *              *sleep_type_b        - Where SLP_TYPb is returned
 *
 * RETURN:      Status - ACPI status
 *
 * DESCRIPTION: Obtain the SLP_TYPa and SLP_TYPb values for the requested sleep
 *              state.
 *
 ******************************************************************************/

acpi_status
acpi_get_sleep_type_data(u8 sleep_state, u8 * sleep_type_a, u8 * sleep_type_b)
{
      acpi_status status = AE_OK;
      struct acpi_evaluate_info *info;

      ACPI_FUNCTION_TRACE(acpi_get_sleep_type_data);

      /* Validate parameters */

      if ((sleep_state > ACPI_S_STATES_MAX) || !sleep_type_a || !sleep_type_b) {
            return_ACPI_STATUS(AE_BAD_PARAMETER);
      }

      /* Allocate the evaluation information block */

      info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
      if (!info) {
            return_ACPI_STATUS(AE_NO_MEMORY);
      }

      info->pathname =
          ACPI_CAST_PTR(char, acpi_gbl_sleep_state_names[sleep_state]);

      /* Evaluate the namespace object containing the values for this state */

      status = acpi_ns_evaluate(info);
      if (ACPI_FAILURE(status)) {
            ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
                          "%s while evaluating SleepState [%s]\n",
                          acpi_format_exception(status),
                          info->pathname));

            goto cleanup;
      }

      /* Must have a return object */

      if (!info->return_object) {
            ACPI_ERROR((AE_INFO, "No Sleep State object returned from [%s]",
                      info->pathname));
            status = AE_NOT_EXIST;
      }

      /* It must be of type Package */

      else if (ACPI_GET_OBJECT_TYPE(info->return_object) != ACPI_TYPE_PACKAGE) {
            ACPI_ERROR((AE_INFO,
                      "Sleep State return object is not a Package"));
            status = AE_AML_OPERAND_TYPE;
      }

      /*
       * The package must have at least two elements. NOTE (March 2005): This
       * goes against the current ACPI spec which defines this object as a
       * package with one encoded DWORD element. However, existing practice
       * by BIOS vendors seems to be to have 2 or more elements, at least
       * one per sleep type (A/B).
       */
      else if (info->return_object->package.count < 2) {
            ACPI_ERROR((AE_INFO,
                      "Sleep State return package does not have at least two elements"));
            status = AE_AML_NO_OPERAND;
      }

      /* The first two elements must both be of type Integer */

      else if ((ACPI_GET_OBJECT_TYPE(info->return_object->package.elements[0])
              != ACPI_TYPE_INTEGER) ||
             (ACPI_GET_OBJECT_TYPE(info->return_object->package.elements[1])
              != ACPI_TYPE_INTEGER)) {
            ACPI_ERROR((AE_INFO,
                      "Sleep State return package elements are not both Integers (%s, %s)",
                      acpi_ut_get_object_type_name(info->return_object->
                                           package.elements[0]),
                      acpi_ut_get_object_type_name(info->return_object->
                                           package.elements[1])));
            status = AE_AML_OPERAND_TYPE;
      } else {
            /* Valid _Sx_ package size, type, and value */

            *sleep_type_a = (u8)
                (info->return_object->package.elements[0])->integer.value;
            *sleep_type_b = (u8)
                (info->return_object->package.elements[1])->integer.value;
      }

      if (ACPI_FAILURE(status)) {
            ACPI_EXCEPTION((AE_INFO, status,
                        "While evaluating SleepState [%s], bad Sleep object %p type %s",
                        info->pathname, info->return_object,
                        acpi_ut_get_object_type_name(info->
                                               return_object)));
      }

      acpi_ut_remove_reference(info->return_object);

      cleanup:
      ACPI_FREE(info);
      return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_get_sleep_type_data)

/*******************************************************************************
 *
 * FUNCTION:    acpi_hw_get_register_bit_mask
 *
 * PARAMETERS:  register_id         - Index of ACPI Register to access
 *
 * RETURN:      The bitmask to be used when accessing the register
 *
 * DESCRIPTION: Map register_id into a register bitmask.
 *
 ******************************************************************************/
struct acpi_bit_register_info *acpi_hw_get_bit_register_info(u32 register_id)
{
      ACPI_FUNCTION_ENTRY();

      if (register_id > ACPI_BITREG_MAX) {
            ACPI_ERROR((AE_INFO, "Invalid BitRegister ID: %X",
                      register_id));
            return (NULL);
      }

      return (&acpi_gbl_bit_register_info[register_id]);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_get_register
 *
 * PARAMETERS:  register_id     - ID of ACPI bit_register to access
 *              return_value    - Value that was read from the register
 *
 * RETURN:      Status and the value read from specified Register. Value
 *              returned is normalized to bit0 (is shifted all the way right)
 *
 * DESCRIPTION: ACPI bit_register read function.
 *
 ******************************************************************************/

acpi_status acpi_get_register_unlocked(u32 register_id, u32 * return_value)
{
      u32 register_value = 0;
      struct acpi_bit_register_info *bit_reg_info;
      acpi_status status;

      ACPI_FUNCTION_TRACE(acpi_get_register);

      /* Get the info structure corresponding to the requested ACPI Register */

      bit_reg_info = acpi_hw_get_bit_register_info(register_id);
      if (!bit_reg_info) {
            return_ACPI_STATUS(AE_BAD_PARAMETER);
      }

      /* Read from the register */

      status = acpi_hw_register_read(bit_reg_info->parent_register,
                               &register_value);

      if (ACPI_SUCCESS(status)) {

            /* Normalize the value that was read */

            register_value =
                ((register_value & bit_reg_info->access_bit_mask)
                 >> bit_reg_info->bit_position);

            *return_value = register_value;

            ACPI_DEBUG_PRINT((ACPI_DB_IO, "Read value %8.8X register %X\n",
                          register_value,
                          bit_reg_info->parent_register));
      }

      return_ACPI_STATUS(status);
}

acpi_status acpi_get_register(u32 register_id, u32 * return_value)
{
      acpi_status status;
      acpi_cpu_flags flags;
      flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);
      status = acpi_get_register_unlocked(register_id, return_value);
      acpi_os_release_lock(acpi_gbl_hardware_lock, flags);
      return status;
}

ACPI_EXPORT_SYMBOL(acpi_get_register)

/*******************************************************************************
 *
 * FUNCTION:    acpi_set_register
 *
 * PARAMETERS:  register_id     - ID of ACPI bit_register to access
 *              Value           - (only used on write) value to write to the
 *                                Register, NOT pre-normalized to the bit pos
 *
 * RETURN:      Status
 *
 * DESCRIPTION: ACPI Bit Register write function.
 *
 ******************************************************************************/
acpi_status acpi_set_register(u32 register_id, u32 value)
{
      u32 register_value = 0;
      struct acpi_bit_register_info *bit_reg_info;
      acpi_status status;
      acpi_cpu_flags lock_flags;

      ACPI_FUNCTION_TRACE_U32(acpi_set_register, register_id);

      /* Get the info structure corresponding to the requested ACPI Register */

      bit_reg_info = acpi_hw_get_bit_register_info(register_id);
      if (!bit_reg_info) {
            ACPI_ERROR((AE_INFO, "Bad ACPI HW RegisterId: %X",
                      register_id));
            return_ACPI_STATUS(AE_BAD_PARAMETER);
      }

      lock_flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);

      /* Always do a register read first so we can insert the new bits  */

      status = acpi_hw_register_read(bit_reg_info->parent_register,
                               &register_value);
      if (ACPI_FAILURE(status)) {
            goto unlock_and_exit;
      }

      /*
       * Decode the Register ID
       * Register ID = [Register block ID] | [bit ID]
       *
       * Check bit ID to fine locate Register offset.
       * Check Mask to determine Register offset, and then read-write.
       */
      switch (bit_reg_info->parent_register) {
      case ACPI_REGISTER_PM1_STATUS:

            /*
             * Status Registers are different from the rest. Clear by
             * writing 1, and writing 0 has no effect. So, the only relevant
             * information is the single bit we're interested in, all others should
             * be written as 0 so they will be left unchanged.
             */
            value = ACPI_REGISTER_PREPARE_BITS(value,
                                       bit_reg_info->bit_position,
                                       bit_reg_info->
                                       access_bit_mask);
            if (value) {
                  status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
                                          (u16) value);
                  register_value = 0;
            }
            break;

      case ACPI_REGISTER_PM1_ENABLE:

            ACPI_REGISTER_INSERT_VALUE(register_value,
                                 bit_reg_info->bit_position,
                                 bit_reg_info->access_bit_mask,
                                 value);

            status = acpi_hw_register_write(ACPI_REGISTER_PM1_ENABLE,
                                    (u16) register_value);
            break;

      case ACPI_REGISTER_PM1_CONTROL:

            /*
             * Write the PM1 Control register.
             * Note that at this level, the fact that there are actually TWO
             * registers (A and B - and B may not exist) is abstracted.
             */
            ACPI_DEBUG_PRINT((ACPI_DB_IO, "PM1 control: Read %X\n",
                          register_value));

            ACPI_REGISTER_INSERT_VALUE(register_value,
                                 bit_reg_info->bit_position,
                                 bit_reg_info->access_bit_mask,
                                 value);

            status = acpi_hw_register_write(ACPI_REGISTER_PM1_CONTROL,
                                    (u16) register_value);
            break;

      case ACPI_REGISTER_PM2_CONTROL:

            status = acpi_hw_register_read(ACPI_REGISTER_PM2_CONTROL,
                                     &register_value);
            if (ACPI_FAILURE(status)) {
                  goto unlock_and_exit;
            }

            ACPI_DEBUG_PRINT((ACPI_DB_IO,
                          "PM2 control: Read %X from %8.8X%8.8X\n",
                          register_value,
                          ACPI_FORMAT_UINT64(acpi_gbl_FADT.
                                         xpm2_control_block.
                                         address)));

            ACPI_REGISTER_INSERT_VALUE(register_value,
                                 bit_reg_info->bit_position,
                                 bit_reg_info->access_bit_mask,
                                 value);

            ACPI_DEBUG_PRINT((ACPI_DB_IO,
                          "About to write %4.4X to %8.8X%8.8X\n",
                          register_value,
                          ACPI_FORMAT_UINT64(acpi_gbl_FADT.
                                         xpm2_control_block.
                                         address)));

            status = acpi_hw_register_write(ACPI_REGISTER_PM2_CONTROL,
                                    (u8) (register_value));
            break;

      default:
            break;
      }

      unlock_and_exit:

      acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);

      /* Normalize the value that was read */

      ACPI_DEBUG_EXEC(register_value =
                  ((register_value & bit_reg_info->access_bit_mask) >>
                   bit_reg_info->bit_position));

      ACPI_DEBUG_PRINT((ACPI_DB_IO,
                    "Set bits: %8.8X actual %8.8X register %X\n", value,
                    register_value, bit_reg_info->parent_register));
      return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_set_register)

/******************************************************************************
 *
 * FUNCTION:    acpi_hw_register_read
 *
 * PARAMETERS:  register_id         - ACPI Register ID
 *              return_value        - Where the register value is returned
 *
 * RETURN:      Status and the value read.
 *
 * DESCRIPTION: Read from the specified ACPI register
 *
 ******************************************************************************/
acpi_status
acpi_hw_register_read(u32 register_id, u32 * return_value)
{
      u32 value1 = 0;
      u32 value2 = 0;
      acpi_status status;

      ACPI_FUNCTION_TRACE(hw_register_read);

      switch (register_id) {
      case ACPI_REGISTER_PM1_STATUS:      /* 16-bit access */

            status =
                acpi_hw_low_level_read(16, &value1,
                                 &acpi_gbl_FADT.xpm1a_event_block);
            if (ACPI_FAILURE(status)) {
                  goto exit;
            }

            /* PM1B is optional */

            status =
                acpi_hw_low_level_read(16, &value2,
                                 &acpi_gbl_FADT.xpm1b_event_block);
            value1 |= value2;
            break;

      case ACPI_REGISTER_PM1_ENABLE:      /* 16-bit access */

            status =
                acpi_hw_low_level_read(16, &value1, &acpi_gbl_xpm1a_enable);
            if (ACPI_FAILURE(status)) {
                  goto exit;
            }

            /* PM1B is optional */

            status =
                acpi_hw_low_level_read(16, &value2, &acpi_gbl_xpm1b_enable);
            value1 |= value2;
            break;

      case ACPI_REGISTER_PM1_CONTROL:     /* 16-bit access */

            status =
                acpi_hw_low_level_read(16, &value1,
                                 &acpi_gbl_FADT.xpm1a_control_block);
            if (ACPI_FAILURE(status)) {
                  goto exit;
            }

            status =
                acpi_hw_low_level_read(16, &value2,
                                 &acpi_gbl_FADT.xpm1b_control_block);
            value1 |= value2;
            break;

      case ACPI_REGISTER_PM2_CONTROL:     /* 8-bit access */

            status =
                acpi_hw_low_level_read(8, &value1,
                                 &acpi_gbl_FADT.xpm2_control_block);
            break;

      case ACPI_REGISTER_PM_TIMER:  /* 32-bit access */

            status =
                acpi_hw_low_level_read(32, &value1,
                                 &acpi_gbl_FADT.xpm_timer_block);
            break;

      case ACPI_REGISTER_SMI_COMMAND_BLOCK:     /* 8-bit access */

            status =
                acpi_os_read_port(acpi_gbl_FADT.smi_command, &value1, 8);
            break;

      default:
            ACPI_ERROR((AE_INFO, "Unknown Register ID: %X", register_id));
            status = AE_BAD_PARAMETER;
            break;
      }

      exit:

      if (ACPI_SUCCESS(status)) {
            *return_value = value1;
      }

      return_ACPI_STATUS(status);
}

/******************************************************************************
 *
 * FUNCTION:    acpi_hw_register_write
 *
 * PARAMETERS:  register_id         - ACPI Register ID
 *              Value               - The value to write
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Write to the specified ACPI register
 *
 * NOTE: In accordance with the ACPI specification, this function automatically
 * preserves the value of the following bits, meaning that these bits cannot be
 * changed via this interface:
 *
 * PM1_CONTROL[0] = SCI_EN
 * PM1_CONTROL[9]
 * PM1_STATUS[11]
 *
 * ACPI References:
 * 1) Hardware Ignored Bits: When software writes to a register with ignored
 *      bit fields, it preserves the ignored bit fields
 * 2) SCI_EN: OSPM always preserves this bit position
 *
 ******************************************************************************/

acpi_status acpi_hw_register_write(u32 register_id, u32 value)
{
      acpi_status status;
      u32 read_value;

      ACPI_FUNCTION_TRACE(hw_register_write);

      switch (register_id) {
      case ACPI_REGISTER_PM1_STATUS:      /* 16-bit access */

            /* Perform a read first to preserve certain bits (per ACPI spec) */

            status = acpi_hw_register_read(ACPI_REGISTER_PM1_STATUS,
                                     &read_value);
            if (ACPI_FAILURE(status)) {
                  goto exit;
            }

            /* Insert the bits to be preserved */

            ACPI_INSERT_BITS(value, ACPI_PM1_STATUS_PRESERVED_BITS,
                         read_value);

            /* Now we can write the data */

            status =
                acpi_hw_low_level_write(16, value,
                                  &acpi_gbl_FADT.xpm1a_event_block);
            if (ACPI_FAILURE(status)) {
                  goto exit;
            }

            /* PM1B is optional */

            status =
                acpi_hw_low_level_write(16, value,
                                  &acpi_gbl_FADT.xpm1b_event_block);
            break;

      case ACPI_REGISTER_PM1_ENABLE:      /* 16-bit access */

            status =
                acpi_hw_low_level_write(16, value, &acpi_gbl_xpm1a_enable);
            if (ACPI_FAILURE(status)) {
                  goto exit;
            }

            /* PM1B is optional */

            status =
                acpi_hw_low_level_write(16, value, &acpi_gbl_xpm1b_enable);
            break;

      case ACPI_REGISTER_PM1_CONTROL:     /* 16-bit access */

            /*
             * Perform a read first to preserve certain bits (per ACPI spec)
             */
            status = acpi_hw_register_read(ACPI_REGISTER_PM1_CONTROL,
                                     &read_value);
            if (ACPI_FAILURE(status)) {
                  goto exit;
            }

            /* Insert the bits to be preserved */

            ACPI_INSERT_BITS(value, ACPI_PM1_CONTROL_PRESERVED_BITS,
                         read_value);

            /* Now we can write the data */

            status =
                acpi_hw_low_level_write(16, value,
                                  &acpi_gbl_FADT.xpm1a_control_block);
            if (ACPI_FAILURE(status)) {
                  goto exit;
            }

            status =
                acpi_hw_low_level_write(16, value,
                                  &acpi_gbl_FADT.xpm1b_control_block);
            break;

      case ACPI_REGISTER_PM1A_CONTROL:    /* 16-bit access */

            status =
                acpi_hw_low_level_write(16, value,
                                  &acpi_gbl_FADT.xpm1a_control_block);
            break;

      case ACPI_REGISTER_PM1B_CONTROL:    /* 16-bit access */

            status =
                acpi_hw_low_level_write(16, value,
                                  &acpi_gbl_FADT.xpm1b_control_block);
            break;

      case ACPI_REGISTER_PM2_CONTROL:     /* 8-bit access */

            status =
                acpi_hw_low_level_write(8, value,
                                  &acpi_gbl_FADT.xpm2_control_block);
            break;

      case ACPI_REGISTER_PM_TIMER:  /* 32-bit access */

            status =
                acpi_hw_low_level_write(32, value,
                                  &acpi_gbl_FADT.xpm_timer_block);
            break;

      case ACPI_REGISTER_SMI_COMMAND_BLOCK:     /* 8-bit access */

            /* SMI_CMD is currently always in IO space */

            status =
                acpi_os_write_port(acpi_gbl_FADT.smi_command, value, 8);
            break;

      default:
            status = AE_BAD_PARAMETER;
            break;
      }

      exit:
      return_ACPI_STATUS(status);
}

/******************************************************************************
 *
 * FUNCTION:    acpi_hw_low_level_read
 *
 * PARAMETERS:  Width               - 8, 16, or 32
 *              Value               - Where the value is returned
 *              Reg                 - GAS register structure
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Read from either memory or IO space.
 *
 ******************************************************************************/

acpi_status
acpi_hw_low_level_read(u32 width, u32 * value, struct acpi_generic_address *reg)
{
      u64 address;
      acpi_status status;

      ACPI_FUNCTION_NAME(hw_low_level_read);

      /*
       * Must have a valid pointer to a GAS structure, and
       * a non-zero address within. However, don't return an error
       * because the PM1A/B code must not fail if B isn't present.
       */
      if (!reg) {
            return (AE_OK);
      }

      /* Get a local copy of the address. Handles possible alignment issues */

      ACPI_MOVE_64_TO_64(&address, &reg->address);
      if (!address) {
            return (AE_OK);
      }
      *value = 0;

      /*
       * Two address spaces supported: Memory or IO.
       * PCI_Config is not supported here because the GAS struct is insufficient
       */
      switch (reg->space_id) {
      case ACPI_ADR_SPACE_SYSTEM_MEMORY:

            status = acpi_os_read_memory((acpi_physical_address) address,
                                   value, width);
            break;

      case ACPI_ADR_SPACE_SYSTEM_IO:

            status =
                acpi_os_read_port((acpi_io_address) address, value, width);
            break;

      default:
            ACPI_ERROR((AE_INFO,
                      "Unsupported address space: %X", reg->space_id));
            return (AE_BAD_PARAMETER);
      }

      ACPI_DEBUG_PRINT((ACPI_DB_IO,
                    "Read:  %8.8X width %2d from %8.8X%8.8X (%s)\n",
                    *value, width, ACPI_FORMAT_UINT64(address),
                    acpi_ut_get_region_name(reg->space_id)));

      return (status);
}

/******************************************************************************
 *
 * FUNCTION:    acpi_hw_low_level_write
 *
 * PARAMETERS:  Width               - 8, 16, or 32
 *              Value               - To be written
 *              Reg                 - GAS register structure
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Write to either memory or IO space.
 *
 ******************************************************************************/

acpi_status
acpi_hw_low_level_write(u32 width, u32 value, struct acpi_generic_address * reg)
{
      u64 address;
      acpi_status status;

      ACPI_FUNCTION_NAME(hw_low_level_write);

      /*
       * Must have a valid pointer to a GAS structure, and
       * a non-zero address within. However, don't return an error
       * because the PM1A/B code must not fail if B isn't present.
       */
      if (!reg) {
            return (AE_OK);
      }

      /* Get a local copy of the address. Handles possible alignment issues */

      ACPI_MOVE_64_TO_64(&address, &reg->address);
      if (!address) {
            return (AE_OK);
      }

      /*
       * Two address spaces supported: Memory or IO.
       * PCI_Config is not supported here because the GAS struct is insufficient
       */
      switch (reg->space_id) {
      case ACPI_ADR_SPACE_SYSTEM_MEMORY:

            status = acpi_os_write_memory((acpi_physical_address) address,
                                    value, width);
            break;

      case ACPI_ADR_SPACE_SYSTEM_IO:

            status = acpi_os_write_port((acpi_io_address) address, value,
                                  width);
            break;

      default:
            ACPI_ERROR((AE_INFO,
                      "Unsupported address space: %X", reg->space_id));
            return (AE_BAD_PARAMETER);
      }

      ACPI_DEBUG_PRINT((ACPI_DB_IO,
                    "Wrote: %8.8X width %2d   to %8.8X%8.8X (%s)\n",
                    value, width, ACPI_FORMAT_UINT64(address),
                    acpi_ut_get_region_name(reg->space_id)));

      return (status);
}

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