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 - 2007, 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_set_mode
  53  *
  54  * PARAMETERS:  Mode            - SYS_MODE_ACPI or SYS_MODE_LEGACY
  55  *
  56  * RETURN:      Status
  57  *
  58  * DESCRIPTION: Transitions the system into the requested mode.
  59  *
  60  ******************************************************************************/
  61 acpi_status acpi_hw_set_mode(u32 mode)
  62 {
  63
  64         acpi_status status;
  65         u32 retry;
  66
  67         ACPI_FUNCTION_TRACE(hw_set_mode);
  68
  69         /*
  70          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
  71          * system does not support mode transition.
  72          */
  73         if (!acpi_gbl_FADT.smi_command) {
  74                 ACPI_ERROR((AE_INFO,
  75                             "No SMI_CMD in FADT, mode transition failed"));
  76                 return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
  77         }
  78
  79         /*
  80          * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
  81          * in FADT: If it is zero, enabling or disabling is not supported.
  82          * As old systems may have used zero for mode transition,
  83          * we make sure both the numbers are zero to determine these
  84          * transitions are not supported.
  85          */
  86         if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) {
  87                 ACPI_ERROR((AE_INFO,
  88                             "No ACPI mode transition supported in this system (enable/disable both zero)"));
  89                 return_ACPI_STATUS(AE_OK);
  90         }
  91
  92         switch (mode) {
  93         case ACPI_SYS_MODE_ACPI:
  94
  95                 /* BIOS should have disabled ALL fixed and GP events */
  96
  97                 status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
  98                                             (u32) acpi_gbl_FADT.acpi_enable, 8);
  99                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 100                                   "Attempting to enable ACPI mode\n"));
 101                 break;
 102
 103         case ACPI_SYS_MODE_LEGACY:
 104
 105                 /*
 106                  * BIOS should clear all fixed status bits and restore fixed event
 107                  * enable bits to default
 108                  */
 109                 status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
 110                                             (u32) acpi_gbl_FADT.acpi_disable,
 111                                             8);
 112                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 113                                   "Attempting to enable Legacy (non-ACPI) mode\n"));
 114                 break;
 115
 116         default:
 117                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 118         }
 119
 120         if (ACPI_FAILURE(status)) {
 121                 ACPI_EXCEPTION((AE_INFO, status,
 122                                 "Could not write ACPI mode change"));
 123                 return_ACPI_STATUS(status);
 124         }
 125
 126         /*
 127          * Some hardware takes a LONG time to switch modes. Give them 3 sec to
 128          * do so, but allow faster systems to proceed more quickly.
 129          */
 130         retry = 3000;
 131         while (retry) {
 132                 if (acpi_hw_get_mode() == mode) {
 133                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 134                                           "Mode %X successfully enabled\n",
 135                                           mode));
 136                         return_ACPI_STATUS(AE_OK);
 137                 }
 138                 acpi_os_stall(1000);
 139                 retry--;
 140         }
 141
 142         ACPI_ERROR((AE_INFO, "Hardware did not change modes"));
 143         return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
 144 }
 145
 146 /*******************************************************************************
 147  *
 148  * FUNCTION:    acpi_hw_get_mode
 149  *
 150  * PARAMETERS:  none
 151  *
 152  * RETURN:      SYS_MODE_ACPI or SYS_MODE_LEGACY
 153  *
 154  * DESCRIPTION: Return current operating state of system.  Determined by
 155  *              querying the SCI_EN bit.
 156  *
 157  ******************************************************************************/
 158
 159 u32 acpi_hw_get_mode(void)
 160 {
 161         acpi_status status;
 162         u32 value;
 163
 164         ACPI_FUNCTION_TRACE(hw_get_mode);
 165
 166         /*
 167          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
 168          * system does not support mode transition.
 169          */
 170         if (!acpi_gbl_FADT.smi_command) {
 171                 return_UINT32(ACPI_SYS_MODE_ACPI);
 172         }
 173
 174         status = acpi_get_register(ACPI_BITREG_SCI_ENABLE, &value);
 175         if (ACPI_FAILURE(status)) {
 176                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 177         }
 178
 179         if (value) {
 180                 return_UINT32(ACPI_SYS_MODE_ACPI);
 181         } else {
 182                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 183         }
 184 }