drivers/acpi/acpica/hwacpi.c

   1 /******************************************************************************
   2  *
   3  * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2013, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include "accommon.h"
  46
  47 #define _COMPONENT          ACPI_HARDWARE
  48 ACPI_MODULE_NAME("hwacpi")
  49
  50 #if (!ACPI_REDUCED_HARDWARE)    /* Entire module */
  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
  67         ACPI_FUNCTION_TRACE(hw_set_mode);
  68
  69         /* If the Hardware Reduced flag is set, machine is always in acpi mode */
  70
  71         if (acpi_gbl_reduced_hardware) {
  72                 return_ACPI_STATUS(AE_OK);
  73         }
  74
  75         /*
  76          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
  77          * system does not support mode transition.
  78          */
  79         if (!acpi_gbl_FADT.smi_command) {
  80                 ACPI_ERROR((AE_INFO,
  81                             "No SMI_CMD in FADT, mode transition failed"));
  82                 return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
  83         }
  84
  85         /*
  86          * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
  87          * in FADT: If it is zero, enabling or disabling is not supported.
  88          * As old systems may have used zero for mode transition,
  89          * we make sure both the numbers are zero to determine these
  90          * transitions are not supported.
  91          */
  92         if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) {
  93                 ACPI_ERROR((AE_INFO,
  94                             "No ACPI mode transition supported in this system "
  95                             "(enable/disable both zero)"));
  96                 return_ACPI_STATUS(AE_OK);
  97         }
  98
  99         switch (mode) {
 100         case ACPI_SYS_MODE_ACPI:
 101
 102                 /* BIOS should have disabled ALL fixed and GP events */
 103
 104                 status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
 105                                             (u32) acpi_gbl_FADT.acpi_enable, 8);
 106                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 107                                   "Attempting to enable ACPI mode\n"));
 108                 break;
 109
 110         case ACPI_SYS_MODE_LEGACY:
 111                 /*
 112                  * BIOS should clear all fixed status bits and restore fixed event
 113                  * enable bits to default
 114                  */
 115                 status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
 116                                             (u32)acpi_gbl_FADT.acpi_disable, 8);
 117                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 118                                   "Attempting to enable Legacy (non-ACPI) mode\n"));
 119                 break;
 120
 121         default:
 122
 123                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 124         }
 125
 126         if (ACPI_FAILURE(status)) {
 127                 ACPI_EXCEPTION((AE_INFO, status,
 128                                 "Could not write ACPI mode change"));
 129                 return_ACPI_STATUS(status);
 130         }
 131
 132         return_ACPI_STATUS(AE_OK);
 133 }
 134
 135 /*******************************************************************************
 136  *
 137  * FUNCTION:    acpi_hw_get_mode
 138  *
 139  * PARAMETERS:  none
 140  *
 141  * RETURN:      SYS_MODE_ACPI or SYS_MODE_LEGACY
 142  *
 143  * DESCRIPTION: Return current operating state of system. Determined by
 144  *              querying the SCI_EN bit.
 145  *
 146  ******************************************************************************/
 147
 148 u32 acpi_hw_get_mode(void)
 149 {
 150         acpi_status status;
 151         u32 value;
 152
 153         ACPI_FUNCTION_TRACE(hw_get_mode);
 154
 155         /* If the Hardware Reduced flag is set, machine is always in acpi mode */
 156
 157         if (acpi_gbl_reduced_hardware) {
 158                 return_UINT32(ACPI_SYS_MODE_ACPI);
 159         }
 160
 161         /*
 162          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
 163          * system does not support mode transition.
 164          */
 165         if (!acpi_gbl_FADT.smi_command) {
 166                 return_UINT32(ACPI_SYS_MODE_ACPI);
 167         }
 168
 169         status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value);
 170         if (ACPI_FAILURE(status)) {
 171                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 172         }
 173
 174         if (value) {
 175                 return_UINT32(ACPI_SYS_MODE_ACPI);
 176         } else {
 177                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 178         }
 179 }
 180
 181 #endif                          /* !ACPI_REDUCED_HARDWARE */