diff options
Diffstat (limited to 'drivers/acpi/acpica/hwacpi.c')
| -rw-r--r-- | drivers/acpi/acpica/hwacpi.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/hwacpi.c b/drivers/acpi/acpica/hwacpi.c new file mode 100644 index 000000000..9b9aac27f --- /dev/null +++ b/drivers/acpi/acpica/hwacpi.c @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 +/****************************************************************************** + * + * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface + * + * Copyright (C) 2000 - 2020, Intel Corp. + * + *****************************************************************************/ + +#include <acpi/acpi.h> +#include "accommon.h" + +#define _COMPONENT ACPI_HARDWARE +ACPI_MODULE_NAME("hwacpi") + +#if (!ACPI_REDUCED_HARDWARE) /* Entire module */ +/****************************************************************************** + * + * FUNCTION: acpi_hw_set_mode + * + * PARAMETERS: mode - SYS_MODE_ACPI or SYS_MODE_LEGACY + * + * RETURN: Status + * + * DESCRIPTION: Transitions the system into the requested mode. + * + ******************************************************************************/ +acpi_status acpi_hw_set_mode(u32 mode) +{ + + acpi_status status; + + ACPI_FUNCTION_TRACE(hw_set_mode); + + /* If the Hardware Reduced flag is set, machine is always in acpi mode */ + + if (acpi_gbl_reduced_hardware) { + return_ACPI_STATUS(AE_OK); + } + + /* + * ACPI 2.0 clarified that if SMI_CMD in FADT is zero, + * system does not support mode transition. + */ + if (!acpi_gbl_FADT.smi_command) { + ACPI_ERROR((AE_INFO, + "No SMI_CMD in FADT, mode transition failed")); + return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE); + } + + /* + * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE + * in FADT: If it is zero, enabling or disabling is not supported. + * As old systems may have used zero for mode transition, + * we make sure both the numbers are zero to determine these + * transitions are not supported. + */ + if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) { + ACPI_ERROR((AE_INFO, + "No ACPI mode transition supported in this system " + "(enable/disable both zero)")); + return_ACPI_STATUS(AE_OK); + } + + switch (mode) { + case ACPI_SYS_MODE_ACPI: + + /* BIOS should have disabled ALL fixed and GP events */ + + status = acpi_hw_write_port(acpi_gbl_FADT.smi_command, + (u32) acpi_gbl_FADT.acpi_enable, 8); + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "Attempting to enable ACPI mode\n")); + break; + + case ACPI_SYS_MODE_LEGACY: + /* + * BIOS should clear all fixed status bits and restore fixed event + * enable bits to default + */ + status = acpi_hw_write_port(acpi_gbl_FADT.smi_command, + (u32)acpi_gbl_FADT.acpi_disable, 8); + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "Attempting to enable Legacy (non-ACPI) mode\n")); + break; + + default: + + return_ACPI_STATUS(AE_BAD_PARAMETER); + } + + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, + "Could not write ACPI mode change")); + return_ACPI_STATUS(status); + } + + return_ACPI_STATUS(AE_OK); +} + +/******************************************************************************* + * + * FUNCTION: acpi_hw_get_mode + * + * PARAMETERS: none + * + * RETURN: SYS_MODE_ACPI or SYS_MODE_LEGACY + * + * DESCRIPTION: Return current operating state of system. Determined by + * querying the SCI_EN bit. + * + ******************************************************************************/ + +u32 acpi_hw_get_mode(void) +{ + acpi_status status; + u32 value; + + ACPI_FUNCTION_TRACE(hw_get_mode); + + /* If the Hardware Reduced flag is set, machine is always in acpi mode */ + + if (acpi_gbl_reduced_hardware) { + return_UINT32(ACPI_SYS_MODE_ACPI); + } + + /* + * ACPI 2.0 clarified that if SMI_CMD in FADT is zero, + * system does not support mode transition. + */ + if (!acpi_gbl_FADT.smi_command) { + return_UINT32(ACPI_SYS_MODE_ACPI); + } + + status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value); + if (ACPI_FAILURE(status)) { + return_UINT32(ACPI_SYS_MODE_LEGACY); + } + + if (value) { + return_UINT32(ACPI_SYS_MODE_ACPI); + } else { + return_UINT32(ACPI_SYS_MODE_LEGACY); + } +} + +#endif /* !ACPI_REDUCED_HARDWARE */ |