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1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.02/******************************************************************************3 *4 * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface5 *6 * Copyright (C) 2000 - 2023, Intel Corp.7 *8 *****************************************************************************/9 10#include <acpi/acpi.h>11#include "accommon.h"12 13#define _COMPONENT ACPI_HARDWARE14ACPI_MODULE_NAME("hwacpi")15 16#if (!ACPI_REDUCED_HARDWARE) /* Entire module */17/******************************************************************************18 *19 * FUNCTION: acpi_hw_set_mode20 *21 * PARAMETERS: mode - SYS_MODE_ACPI or SYS_MODE_LEGACY22 *23 * RETURN: Status24 *25 * DESCRIPTION: Transitions the system into the requested mode.26 *27 ******************************************************************************/28acpi_status acpi_hw_set_mode(u32 mode)29{30 31 acpi_status status;32 33 ACPI_FUNCTION_TRACE(hw_set_mode);34 35 /* If the Hardware Reduced flag is set, machine is always in acpi mode */36 37 if (acpi_gbl_reduced_hardware) {38 return_ACPI_STATUS(AE_OK);39 }40 41 /*42 * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,43 * system does not support mode transition.44 */45 if (!acpi_gbl_FADT.smi_command) {46 ACPI_ERROR((AE_INFO,47 "No SMI_CMD in FADT, mode transition failed"));48 return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);49 }50 51 /*52 * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE53 * in FADT: If it is zero, enabling or disabling is not supported.54 * As old systems may have used zero for mode transition,55 * we make sure both the numbers are zero to determine these56 * transitions are not supported.57 */58 if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) {59 ACPI_ERROR((AE_INFO,60 "No ACPI mode transition supported in this system "61 "(enable/disable both zero)"));62 return_ACPI_STATUS(AE_OK);63 }64 65 switch (mode) {66 case ACPI_SYS_MODE_ACPI:67 68 /* BIOS should have disabled ALL fixed and GP events */69 70 status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,71 (u32) acpi_gbl_FADT.acpi_enable, 8);72 ACPI_DEBUG_PRINT((ACPI_DB_INFO,73 "Attempting to enable ACPI mode\n"));74 break;75 76 case ACPI_SYS_MODE_LEGACY:77 /*78 * BIOS should clear all fixed status bits and restore fixed event79 * enable bits to default80 */81 status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,82 (u32)acpi_gbl_FADT.acpi_disable, 8);83 ACPI_DEBUG_PRINT((ACPI_DB_INFO,84 "Attempting to enable Legacy (non-ACPI) mode\n"));85 break;86 87 default:88 89 return_ACPI_STATUS(AE_BAD_PARAMETER);90 }91 92 if (ACPI_FAILURE(status)) {93 ACPI_EXCEPTION((AE_INFO, status,94 "Could not write ACPI mode change"));95 return_ACPI_STATUS(status);96 }97 98 return_ACPI_STATUS(AE_OK);99}100 101/*******************************************************************************102 *103 * FUNCTION: acpi_hw_get_mode104 *105 * PARAMETERS: none106 *107 * RETURN: SYS_MODE_ACPI or SYS_MODE_LEGACY108 *109 * DESCRIPTION: Return current operating state of system. Determined by110 * querying the SCI_EN bit.111 *112 ******************************************************************************/113 114u32 acpi_hw_get_mode(void)115{116 acpi_status status;117 u32 value;118 119 ACPI_FUNCTION_TRACE(hw_get_mode);120 121 /* If the Hardware Reduced flag is set, machine is always in acpi mode */122 123 if (acpi_gbl_reduced_hardware) {124 return_UINT32(ACPI_SYS_MODE_ACPI);125 }126 127 /*128 * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,129 * system does not support mode transition.130 */131 if (!acpi_gbl_FADT.smi_command) {132 return_UINT32(ACPI_SYS_MODE_ACPI);133 }134 135 status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value);136 if (ACPI_FAILURE(status)) {137 return_UINT32(ACPI_SYS_MODE_LEGACY);138 }139 140 if (value) {141 return_UINT32(ACPI_SYS_MODE_ACPI);142 } else {143 return_UINT32(ACPI_SYS_MODE_LEGACY);144 }145}146 147#endif /* !ACPI_REDUCED_HARDWARE */148