drivers/acpi/acpica/hwacpi.c

   1
   2 /******************************************************************************
   3  *
   4  * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface
   5  *
   6  *****************************************************************************/
   7
   8 /*
   9  * Copyright (C) 2000 - 2010, Intel Corp.
  10  * All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions, and the following disclaimer,
  17  *    without modification.
  18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  19  *    substantially similar to the "NO WARRANTY" disclaimer below
  20  *    ("Disclaimer") and any redistribution must be conditioned upon
  21  *    including a substantially similar Disclaimer requirement for further
  22  *    binary redistribution.
  23  * 3. Neither the names of the above-listed copyright holders nor the names
  24  *    of any contributors may be used to endorse or promote products derived
  25  *    from this software without specific prior written permission.
  26  *
  27  * Alternatively, this software may be distributed under the terms of the
  28  * GNU General Public License ("GPL") version 2 as published by the Free
  29  * Software Foundation.
  30  *
  31  * NO WARRANTY
  32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  42  * POSSIBILITY OF SUCH DAMAGES.
  43  */
  44
  45 #include <acpi/acpi.h>
  46 #include "accommon.h"
  47
  48 #define _COMPONENT          ACPI_HARDWARE
  49 ACPI_MODULE_NAME("hwacpi")
  50
  51 /******************************************************************************
  52  *
  53  * FUNCTION:    acpi_hw_set_mode
  54  *
  55  * PARAMETERS:  Mode            - SYS_MODE_ACPI or SYS_MODE_LEGACY
  56  *
  57  * RETURN:      Status
  58  *
  59  * DESCRIPTION: Transitions the system into the requested mode.
  60  *
  61  ******************************************************************************/
  62 acpi_status acpi_hw_set_mode(u32 mode)
  63 {
  64
  65         acpi_status status;
  66         u32 retry;
  67
  68         ACPI_FUNCTION_TRACE(hw_set_mode);
  69
  70         /*
  71          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
  72          * system does not support mode transition.
  73          */
  74         if (!acpi_gbl_FADT.smi_command) {
  75                 ACPI_ERROR((AE_INFO,
  76                             "No SMI_CMD in FADT, mode transition failed"));
  77                 return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
  78         }
  79
  80         /*
  81          * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
  82          * in FADT: If it is zero, enabling or disabling is not supported.
  83          * As old systems may have used zero for mode transition,
  84          * we make sure both the numbers are zero to determine these
  85          * transitions are not supported.
  86          */
  87         if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) {
  88                 ACPI_ERROR((AE_INFO,
  89                             "No ACPI mode transition supported in this system "
  90                             "(enable/disable both zero)"));
  91                 return_ACPI_STATUS(AE_OK);
  92         }
  93
  94         switch (mode) {
  95         case ACPI_SYS_MODE_ACPI:
  96
  97                 /* BIOS should have disabled ALL fixed and GP events */
  98
  99                 status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
 100                                             (u32) acpi_gbl_FADT.acpi_enable, 8);
 101                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 102                                   "Attempting to enable ACPI mode\n"));
 103                 break;
 104
 105         case ACPI_SYS_MODE_LEGACY:
 106
 107                 /*
 108                  * BIOS should clear all fixed status bits and restore fixed event
 109                  * enable bits to default
 110                  */
 111                 status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
 112                                             (u32) acpi_gbl_FADT.acpi_disable,
 113                                             8);
 114                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 115                                   "Attempting to enable Legacy (non-ACPI) mode\n"));
 116                 break;
 117
 118         default:
 119                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 120         }
 121
 122         if (ACPI_FAILURE(status)) {
 123                 ACPI_EXCEPTION((AE_INFO, status,
 124                                 "Could not write ACPI mode change"));
 125                 return_ACPI_STATUS(status);
 126         }
 127
 128         /*
 129          * Some hardware takes a LONG time to switch modes. Give them 3 sec to
 130          * do so, but allow faster systems to proceed more quickly.
 131          */
 132         retry = 3000;
 133         while (retry) {
 134                 if (acpi_hw_get_mode() == mode) {
 135                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 136                                           "Mode %X successfully enabled\n",
 137                                           mode));
 138                         return_ACPI_STATUS(AE_OK);
 139                 }
 140                 acpi_os_stall(1000);
 141                 retry--;
 142         }
 143
 144         ACPI_ERROR((AE_INFO, "Hardware did not change modes"));
 145         return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
 146 }
 147
 148 /*******************************************************************************
 149  *
 150  * FUNCTION:    acpi_hw_get_mode
 151  *
 152  * PARAMETERS:  none
 153  *
 154  * RETURN:      SYS_MODE_ACPI or SYS_MODE_LEGACY
 155  *
 156  * DESCRIPTION: Return current operating state of system.  Determined by
 157  *              querying the SCI_EN bit.
 158  *
 159  ******************************************************************************/
 160
 161 u32 acpi_hw_get_mode(void)
 162 {
 163         acpi_status status;
 164         u32 value;
 165
 166         ACPI_FUNCTION_TRACE(hw_get_mode);
 167
 168         /*
 169          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
 170          * system does not support mode transition.
 171          */
 172         if (!acpi_gbl_FADT.smi_command) {
 173                 return_UINT32(ACPI_SYS_MODE_ACPI);
 174         }
 175
 176         status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value);
 177         if (ACPI_FAILURE(status)) {
 178                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 179         }
 180
 181         if (value) {
 182                 return_UINT32(ACPI_SYS_MODE_ACPI);
 183         } else {
 184                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 185         }
 186 }