1 /******************************************************************************
3 * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface
5 *****************************************************************************/
8 * Copyright (C) 2000 - 2015, Intel Corp.
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12 * modification, are permitted provided that the following conditions
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20 * including a substantially similar Disclaimer requirement for further
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23 * of any contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
26 * Alternatively, this software may be distributed under the terms of the
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48 #define _COMPONENT ACPI_HARDWARE
49 ACPI_MODULE_NAME ("hwacpi")
52 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */
53 /******************************************************************************
55 * FUNCTION: AcpiHwSetMode
57 * PARAMETERS: Mode - SYS_MODE_ACPI or SYS_MODE_LEGACY
61 * DESCRIPTION: Transitions the system into the requested mode.
63 ******************************************************************************/
74 ACPI_FUNCTION_TRACE (HwSetMode);
77 /* If the Hardware Reduced flag is set, machine is always in acpi mode */
79 if (AcpiGbl_ReducedHardware)
81 return_ACPI_STATUS (AE_OK);
85 * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
86 * system does not support mode transition.
88 if (!AcpiGbl_FADT.SmiCommand)
90 ACPI_ERROR ((AE_INFO, "No SMI_CMD in FADT, mode transition failed"));
91 return_ACPI_STATUS (AE_NO_HARDWARE_RESPONSE);
95 * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
96 * in FADT: If it is zero, enabling or disabling is not supported.
97 * As old systems may have used zero for mode transition,
98 * we make sure both the numbers are zero to determine these
99 * transitions are not supported.
101 if (!AcpiGbl_FADT.AcpiEnable && !AcpiGbl_FADT.AcpiDisable)
103 ACPI_ERROR ((AE_INFO,
104 "No ACPI mode transition supported in this system "
105 "(enable/disable both zero)"));
106 return_ACPI_STATUS (AE_OK);
111 case ACPI_SYS_MODE_ACPI:
113 /* BIOS should have disabled ALL fixed and GP events */
115 Status = AcpiHwWritePort (AcpiGbl_FADT.SmiCommand,
116 (UINT32) AcpiGbl_FADT.AcpiEnable, 8);
117 ACPI_DEBUG_PRINT ((ACPI_DB_INFO, "Attempting to enable ACPI mode\n"));
120 case ACPI_SYS_MODE_LEGACY:
122 * BIOS should clear all fixed status bits and restore fixed event
123 * enable bits to default
125 Status = AcpiHwWritePort (AcpiGbl_FADT.SmiCommand,
126 (UINT32) AcpiGbl_FADT.AcpiDisable, 8);
127 ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
128 "Attempting to enable Legacy (non-ACPI) mode\n"));
133 return_ACPI_STATUS (AE_BAD_PARAMETER);
136 if (ACPI_FAILURE (Status))
138 ACPI_EXCEPTION ((AE_INFO, Status,
139 "Could not write ACPI mode change"));
140 return_ACPI_STATUS (Status);
144 * Some hardware takes a LONG time to switch modes. Give them 3 sec to
145 * do so, but allow faster systems to proceed more quickly.
150 if (AcpiHwGetMode () == Mode)
152 ACPI_DEBUG_PRINT ((ACPI_DB_INFO, "Mode %X successfully enabled\n",
154 return_ACPI_STATUS (AE_OK);
156 AcpiOsStall (ACPI_USEC_PER_MSEC);
160 ACPI_ERROR ((AE_INFO, "Hardware did not change modes"));
161 return_ACPI_STATUS (AE_NO_HARDWARE_RESPONSE);
165 /*******************************************************************************
167 * FUNCTION: AcpiHwGetMode
171 * RETURN: SYS_MODE_ACPI or SYS_MODE_LEGACY
173 * DESCRIPTION: Return current operating state of system. Determined by
174 * querying the SCI_EN bit.
176 ******************************************************************************/
186 ACPI_FUNCTION_TRACE (HwGetMode);
189 /* If the Hardware Reduced flag is set, machine is always in acpi mode */
191 if (AcpiGbl_ReducedHardware)
193 return_UINT32 (ACPI_SYS_MODE_ACPI);
197 * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
198 * system does not support mode transition.
200 if (!AcpiGbl_FADT.SmiCommand)
202 return_UINT32 (ACPI_SYS_MODE_ACPI);
205 Status = AcpiReadBitRegister (ACPI_BITREG_SCI_ENABLE, &Value);
206 if (ACPI_FAILURE (Status))
208 return_UINT32 (ACPI_SYS_MODE_LEGACY);
213 return_UINT32 (ACPI_SYS_MODE_ACPI);
217 return_UINT32 (ACPI_SYS_MODE_LEGACY);
221 #endif /* !ACPI_REDUCED_HARDWARE */