drivers/acpi/hardware/hwacpi.c

   1
   2 /******************************************************************************
   3  *
   4  * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface
   5  *
   6  *****************************************************************************/
   7
   8 /*
   9  * Copyright (C) 2000 - 2006, R. Byron Moore
  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
  47 #define _COMPONENT          ACPI_HARDWARE
  48 ACPI_MODULE_NAME("hwacpi")
  49
  50 /******************************************************************************
  51  *
  52  * FUNCTION:    acpi_hw_initialize
  53  *
  54  * PARAMETERS:  None
  55  *
  56  * RETURN:      Status
  57  *
  58  * DESCRIPTION: Initialize and validate the various ACPI registers defined in
  59  *              the FADT.
  60  *
  61  ******************************************************************************/
  62 acpi_status acpi_hw_initialize(void)
  63 {
  64         acpi_status status;
  65
  66         ACPI_FUNCTION_TRACE(hw_initialize);
  67
  68         /* Sanity check the FADT for valid values */
  69
  70         status = acpi_ut_validate_fadt();
  71         if (ACPI_FAILURE(status)) {
  72                 return_ACPI_STATUS(status);
  73         }
  74
  75         return_ACPI_STATUS(AE_OK);
  76 }
  77
  78 /******************************************************************************
  79  *
  80  * FUNCTION:    acpi_hw_set_mode
  81  *
  82  * PARAMETERS:  Mode            - SYS_MODE_ACPI or SYS_MODE_LEGACY
  83  *
  84  * RETURN:      Status
  85  *
  86  * DESCRIPTION: Transitions the system into the requested mode.
  87  *
  88  ******************************************************************************/
  89
  90 acpi_status acpi_hw_set_mode(u32 mode)
  91 {
  92
  93         acpi_status status;
  94         u32 retry;
  95
  96         ACPI_FUNCTION_TRACE(hw_set_mode);
  97
  98         /*
  99          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
 100          * system does not support mode transition.
 101          */
 102         if (!acpi_gbl_FADT.smi_command) {
 103                 ACPI_ERROR((AE_INFO,
 104                             "No SMI_CMD in FADT, mode transition failed"));
 105                 return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
 106         }
 107
 108         /*
 109          * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
 110          * in FADT: If it is zero, enabling or disabling is not supported.
 111          * As old systems may have used zero for mode transition,
 112          * we make sure both the numbers are zero to determine these
 113          * transitions are not supported.
 114          */
 115         if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) {
 116                 ACPI_ERROR((AE_INFO,
 117                             "No ACPI mode transition supported in this system (enable/disable both zero)"));
 118                 return_ACPI_STATUS(AE_OK);
 119         }
 120
 121         switch (mode) {
 122         case ACPI_SYS_MODE_ACPI:
 123
 124                 /* BIOS should have disabled ALL fixed and GP events */
 125
 126                 status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
 127                                             (u32) acpi_gbl_FADT.acpi_enable, 8);
 128                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 129                                   "Attempting to enable ACPI mode\n"));
 130                 break;
 131
 132         case ACPI_SYS_MODE_LEGACY:
 133
 134                 /*
 135                  * BIOS should clear all fixed status bits and restore fixed event
 136                  * enable bits to default
 137                  */
 138                 status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
 139                                             (u32) acpi_gbl_FADT.acpi_disable,
 140                                             8);
 141                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 142                                   "Attempting to enable Legacy (non-ACPI) mode\n"));
 143                 break;
 144
 145         default:
 146                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 147         }
 148
 149         if (ACPI_FAILURE(status)) {
 150                 ACPI_EXCEPTION((AE_INFO, status,
 151                                 "Could not write ACPI mode change"));
 152                 return_ACPI_STATUS(status);
 153         }
 154
 155         /*
 156          * Some hardware takes a LONG time to switch modes. Give them 3 sec to
 157          * do so, but allow faster systems to proceed more quickly.
 158          */
 159         retry = 3000;
 160         while (retry) {
 161                 if (acpi_hw_get_mode() == mode) {
 162                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 163                                           "Mode %X successfully enabled\n",
 164                                           mode));
 165                         return_ACPI_STATUS(AE_OK);
 166                 }
 167                 acpi_os_stall(1000);
 168                 retry--;
 169         }
 170
 171         ACPI_ERROR((AE_INFO, "Hardware did not change modes"));
 172         return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
 173 }
 174
 175 /*******************************************************************************
 176  *
 177  * FUNCTION:    acpi_hw_get_mode
 178  *
 179  * PARAMETERS:  none
 180  *
 181  * RETURN:      SYS_MODE_ACPI or SYS_MODE_LEGACY
 182  *
 183  * DESCRIPTION: Return current operating state of system.  Determined by
 184  *              querying the SCI_EN bit.
 185  *
 186  ******************************************************************************/
 187
 188 u32 acpi_hw_get_mode(void)
 189 {
 190         acpi_status status;
 191         u32 value;
 192
 193         ACPI_FUNCTION_TRACE(hw_get_mode);
 194
 195         /*
 196          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
 197          * system does not support mode transition.
 198          */
 199         if (!acpi_gbl_FADT.smi_command) {
 200                 return_UINT32(ACPI_SYS_MODE_ACPI);
 201         }
 202
 203         status =
 204             acpi_get_register(ACPI_BITREG_SCI_ENABLE, &value, ACPI_MTX_LOCK);
 205         if (ACPI_FAILURE(status)) {
 206                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 207         }
 208
 209         if (value) {
 210                 return_UINT32(ACPI_SYS_MODE_ACPI);
 211         } else {
 212                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 213         }
 214 }