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 - 2012, 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 #if (!ACPI_REDUCED_HARDWARE)    /* Entire module */
  52 /******************************************************************************
  53  *
  54  * FUNCTION:    acpi_hw_set_mode
  55  *
  56  * PARAMETERS:  Mode            - SYS_MODE_ACPI or SYS_MODE_LEGACY
  57  *
  58  * RETURN:      Status
  59  *
  60  * DESCRIPTION: Transitions the system into the requested mode.
  61  *
  62  ******************************************************************************/
  63 acpi_status acpi_hw_set_mode(u32 mode)
  64 {
  65
  66         acpi_status status;
  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         return_ACPI_STATUS(AE_OK);
 129 }
 130
 131 /*******************************************************************************
 132  *
 133  * FUNCTION:    acpi_hw_get_mode
 134  *
 135  * PARAMETERS:  none
 136  *
 137  * RETURN:      SYS_MODE_ACPI or SYS_MODE_LEGACY
 138  *
 139  * DESCRIPTION: Return current operating state of system.  Determined by
 140  *              querying the SCI_EN bit.
 141  *
 142  ******************************************************************************/
 143
 144 u32 acpi_hw_get_mode(void)
 145 {
 146         acpi_status status;
 147         u32 value;
 148
 149         ACPI_FUNCTION_TRACE(hw_get_mode);
 150
 151         /*
 152          * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
 153          * system does not support mode transition.
 154          */
 155         if (!acpi_gbl_FADT.smi_command) {
 156                 return_UINT32(ACPI_SYS_MODE_ACPI);
 157         }
 158
 159         status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value);
 160         if (ACPI_FAILURE(status)) {
 161                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 162         }
 163
 164         if (value) {
 165                 return_UINT32(ACPI_SYS_MODE_ACPI);
 166         } else {
 167                 return_UINT32(ACPI_SYS_MODE_LEGACY);
 168         }
 169 }
 170
 171 #endif                          /* !ACPI_REDUCED_HARDWARE */