1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 2 /****************************************************************************** 3 * 4 * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface 5 * 6 * Copyright (C) 2000 - 2021, Intel Corp. 7 * 8 *****************************************************************************/ 9 10 #include <acpi/acpi.h> 11 #include "accommon.h" 12 13 #define _COMPONENT ACPI_HARDWARE 14 ACPI_MODULE_NAME("hwacpi") 15 16 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */ 17 /****************************************************************************** 18 * 19 * FUNCTION: acpi_hw_set_mode 20 * 21 * PARAMETERS: mode - SYS_MODE_ACPI or SYS_MODE_LEGACY 22 * 23 * RETURN: Status 24 * 25 * DESCRIPTION: Transitions the system into the requested mode. 26 * 27 ******************************************************************************/ 28 acpi_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_DISABLE 53 * 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 these 56 * 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 event 79 * enable bits to default 80 */ 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_mode 104 * 105 * PARAMETERS: none 106 * 107 * RETURN: SYS_MODE_ACPI or SYS_MODE_LEGACY 108 * 109 * DESCRIPTION: Return current operating state of system. Determined by 110 * querying the SCI_EN bit. 111 * 112 ******************************************************************************/ 113 114 u32 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