/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
 49ACPI_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 ******************************************************************************/
 62acpi_status acpi_hw_set_mode(u32 mode)
 63{
 64
 65	acpi_status status;
 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 "
 89			    "(enable/disable both zero)"));
 90		return_ACPI_STATUS(AE_OK);
 91	}
 92
 93	switch (mode) {
 94	case ACPI_SYS_MODE_ACPI:
 95
 96		/* BIOS should have disabled ALL fixed and GP events */
 97
 98		status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
 99					    (u32) acpi_gbl_FADT.acpi_enable, 8);
100		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
101				  "Attempting to enable ACPI mode\n"));
102		break;
103
104	case ACPI_SYS_MODE_LEGACY:
105
106		/*
107		 * BIOS should clear all fixed status bits and restore fixed event
108		 * enable bits to default
109		 */
110		status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
111					    (u32) acpi_gbl_FADT.acpi_disable,
112					    8);
113		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
114				  "Attempting to enable Legacy (non-ACPI) mode\n"));
115		break;
116
117	default:
118		return_ACPI_STATUS(AE_BAD_PARAMETER);
119	}
120
121	if (ACPI_FAILURE(status)) {
122		ACPI_EXCEPTION((AE_INFO, status,
123				"Could not write ACPI mode change"));
124		return_ACPI_STATUS(status);
125	}
126
127	return_ACPI_STATUS(AE_OK);
128}
129
130/*******************************************************************************
131 *
132 * FUNCTION:    acpi_hw_get_mode
133 *
134 * PARAMETERS:  none
135 *
136 * RETURN:      SYS_MODE_ACPI or SYS_MODE_LEGACY
137 *
138 * DESCRIPTION: Return current operating state of system.  Determined by
139 *              querying the SCI_EN bit.
140 *
141 ******************************************************************************/
142
143u32 acpi_hw_get_mode(void)
144{
145	acpi_status status;
146	u32 value;
147
148	ACPI_FUNCTION_TRACE(hw_get_mode);
149
150	/*
151	 * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
152	 * system does not support mode transition.
153	 */
154	if (!acpi_gbl_FADT.smi_command) {
155		return_UINT32(ACPI_SYS_MODE_ACPI);
156	}
157
158	status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value);
159	if (ACPI_FAILURE(status)) {
160		return_UINT32(ACPI_SYS_MODE_LEGACY);
161	}
162
163	if (value) {
164		return_UINT32(ACPI_SYS_MODE_ACPI);
165	} else {
166		return_UINT32(ACPI_SYS_MODE_LEGACY);
167	}
168}