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hwacpi.c

/******************************************************************************
 *
 * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface
 *
 *****************************************************************************/

/*
 * 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>

#define _COMPONENT          ACPI_HARDWARE
ACPI_MODULE_NAME("hwacpi")

/******************************************************************************
 *
 * FUNCTION:    acpi_hw_set_mode
 *
 * PARAMETERS:  Mode            - SYS_MODE_ACPI or SYS_MODE_LEGACY
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Transitions the system into the requested mode.
 *
 ******************************************************************************/
acpi_status acpi_hw_set_mode(u32 mode)
{

      acpi_status status;
      u32 retry;

      ACPI_FUNCTION_TRACE(hw_set_mode);

      /*
       * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
       * system does not support mode transition.
       */
      if (!acpi_gbl_FADT.smi_command) {
            ACPI_ERROR((AE_INFO,
                      "No SMI_CMD in FADT, mode transition failed"));
            return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
      }

      /*
       * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
       * in FADT: If it is zero, enabling or disabling is not supported.
       * As old systems may have used zero for mode transition,
       * we make sure both the numbers are zero to determine these
       * transitions are not supported.
       */
      if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) {
            ACPI_ERROR((AE_INFO,
                      "No ACPI mode transition supported in this system (enable/disable both zero)"));
            return_ACPI_STATUS(AE_OK);
      }

      switch (mode) {
      case ACPI_SYS_MODE_ACPI:

            /* BIOS should have disabled ALL fixed and GP events */

            status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
                                  (u32) acpi_gbl_FADT.acpi_enable, 8);
            ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "Attempting to enable ACPI mode\n"));
            break;

      case ACPI_SYS_MODE_LEGACY:

            /*
             * BIOS should clear all fixed status bits and restore fixed event
             * enable bits to default
             */
            status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
                                  (u32) acpi_gbl_FADT.acpi_disable,
                                  8);
            ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "Attempting to enable Legacy (non-ACPI) mode\n"));
            break;

      default:
            return_ACPI_STATUS(AE_BAD_PARAMETER);
      }

      if (ACPI_FAILURE(status)) {
            ACPI_EXCEPTION((AE_INFO, status,
                        "Could not write ACPI mode change"));
            return_ACPI_STATUS(status);
      }

      /*
       * Some hardware takes a LONG time to switch modes. Give them 3 sec to
       * do so, but allow faster systems to proceed more quickly.
       */
      retry = 3000;
      while (retry) {
            if (acpi_hw_get_mode() == mode) {
                  ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                "Mode %X successfully enabled\n",
                                mode));
                  return_ACPI_STATUS(AE_OK);
            }
            acpi_os_stall(1000);
            retry--;
      }

      ACPI_ERROR((AE_INFO, "Hardware did not change modes"));
      return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_hw_get_mode
 *
 * PARAMETERS:  none
 *
 * RETURN:      SYS_MODE_ACPI or SYS_MODE_LEGACY
 *
 * DESCRIPTION: Return current operating state of system.  Determined by
 *              querying the SCI_EN bit.
 *
 ******************************************************************************/

u32 acpi_hw_get_mode(void)
{
      acpi_status status;
      u32 value;

      ACPI_FUNCTION_TRACE(hw_get_mode);

      /*
       * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
       * system does not support mode transition.
       */
      if (!acpi_gbl_FADT.smi_command) {
            return_UINT32(ACPI_SYS_MODE_ACPI);
      }

      status = acpi_get_register(ACPI_BITREG_SCI_ENABLE, &value);
      if (ACPI_FAILURE(status)) {
            return_UINT32(ACPI_SYS_MODE_LEGACY);
      }

      if (value) {
            return_UINT32(ACPI_SYS_MODE_ACPI);
      } else {
            return_UINT32(ACPI_SYS_MODE_LEGACY);
      }
}

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