// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 /******************************************************************************* * * Module Name: hwregs - Read/write access functions for the various ACPI * control and status registers. * ******************************************************************************/ #include <acpi/acpi.h> #include "accommon.h" #include "acevents.h" #define _COMPONENT ACPI_HARDWARE ACPI_MODULE_NAME("hwregs") #if (!ACPI_REDUCED_HARDWARE) /* Local Prototypes */ static u8 acpi_hw_get_access_bit_width(u64 address, struct acpi_generic_address *reg, u8 max_bit_width); static acpi_status acpi_hw_read_multiple(u32 *value, struct acpi_generic_address *register_a, struct acpi_generic_address *register_b); static acpi_status acpi_hw_write_multiple(u32 value, struct acpi_generic_address *register_a, struct acpi_generic_address *register_b); #endif /* !ACPI_REDUCED_HARDWARE */ /****************************************************************************** * * FUNCTION: acpi_hw_get_access_bit_width * * PARAMETERS: address - GAS register address * reg - GAS register structure * max_bit_width - Max bit_width supported (32 or 64) * * RETURN: Status * * DESCRIPTION: Obtain optimal access bit width * ******************************************************************************/ static u8 acpi_hw_get_access_bit_width(u64 address, struct acpi_generic_address *reg, u8 max_bit_width) { u8 access_bit_width; /* * GAS format "register", used by FADT: * 1. Detected if bit_offset is 0 and bit_width is 8/16/32/64; * 2. access_size field is ignored and bit_width field is used for * determining the boundary of the IO accesses. * GAS format "region", used by APEI registers: * 1. Detected if bit_offset is not 0 or bit_width is not 8/16/32/64; * 2. access_size field is used for determining the boundary of the * IO accesses; * 3. bit_offset/bit_width fields are used to describe the "region". * * Note: This algorithm assumes that the "Address" fields should always * contain aligned values. */ if (!reg->bit_offset && reg->bit_width && ACPI_IS_POWER_OF_TWO(reg->bit_width) && ACPI_IS_ALIGNED(reg->bit_width, 8)) { access_bit_width = reg->bit_width; } else if (reg->access_width) { access_bit_width = ACPI_ACCESS_BIT_WIDTH(reg->access_width); } else { access_bit_width = ACPI_ROUND_UP_POWER_OF_TWO_8(reg->bit_offset + reg->bit_width); if (access_bit_width <= 8) { access_bit_width = 8; } else { while (!ACPI_IS_ALIGNED(address, access_bit_width >> 3)) { access_bit_width >>= 1; } } } /* Maximum IO port access bit width is 32 */ if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { max_bit_width = 32; } /* * Return access width according to the requested maximum access bit width, * as the caller should know the format of the register and may enforce * a 32-bit accesses. */ if (access_bit_width < max_bit_width) { return (access_bit_width); } return (max_bit_width); } /****************************************************************************** * * FUNCTION: acpi_hw_validate_register * * PARAMETERS: reg - GAS register structure * max_bit_width - Max bit_width supported (32 or 64) * address - Pointer to where the gas->address * is returned * * RETURN: Status * * DESCRIPTION: Validate the contents of a GAS register. Checks the GAS * pointer, Address, space_id, bit_width, and bit_offset. * ******************************************************************************/ acpi_status acpi_hw_validate_register(struct acpi_generic_address *reg, u8 max_bit_width, u64 *address) { u8 bit_width; u8 access_width; /* Must have a valid pointer to a GAS structure */ if (!reg) { return (AE_BAD_PARAMETER); } /* * Copy the target address. This handles possible alignment issues. * Address must not be null. A null address also indicates an optional * ACPI register that is not supported, so no error message. */ ACPI_MOVE_64_TO_64(address, ®->address); if (!(*address)) { return (AE_BAD_ADDRESS); } /* Validate the space_ID */ if ((reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) && (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO)) { ACPI_ERROR((AE_INFO, "Unsupported address space: 0x%X", reg->space_id)); return (AE_SUPPORT); } /* Validate the access_width */ if (reg->access_width > 4) { ACPI_ERROR((AE_INFO, "Unsupported register access width: 0x%X", reg->access_width)); return (AE_SUPPORT); } /* Validate the bit_width, convert access_width into number of bits */ access_width = acpi_hw_get_access_bit_width(*address, reg, max_bit_width); bit_width = ACPI_ROUND_UP(reg->bit_offset + reg->bit_width, access_width); if (max_bit_width < bit_width) { ACPI_WARNING((AE_INFO, "Requested bit width 0x%X is smaller than register bit width 0x%X", max_bit_width, bit_width)); return (AE_SUPPORT); } return (AE_OK); } /****************************************************************************** * * FUNCTION: acpi_hw_read * * PARAMETERS: value - Where the value is returned * reg - GAS register structure * * RETURN: Status * * DESCRIPTION: Read from either memory or IO space. This is a 64-bit max * version of acpi_read. * * LIMITATIONS: <These limitations also apply to acpi_hw_write> * space_ID must be system_memory or system_IO. * ******************************************************************************/ acpi_status acpi_hw_read(u64 *value, struct acpi_generic_address *reg) { u64 address; u8 access_width; u32 bit_width; u8 bit_offset; u64 value64; u32 value32; u8 index; acpi_status status; ACPI_FUNCTION_NAME(hw_read); /* Validate contents of the GAS register */ status = acpi_hw_validate_register(reg, 64, &address); if (ACPI_FAILURE(status)) { return (status); } /* * Initialize entire 64-bit return value to zero, convert access_width * into number of bits based */ *value = 0; access_width = acpi_hw_get_access_bit_width(address, reg, 64); bit_width = reg->bit_offset + reg->bit_width; bit_offset = reg->bit_offset; /* * Two address spaces supported: Memory or IO. PCI_Config is * not supported here because the GAS structure is insufficient */ index = 0; while (bit_width) { if (bit_offset >= access_width) { value64 = 0; bit_offset -= access_width; } else { if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { status = acpi_os_read_memory((acpi_physical_address) address + index * ACPI_DIV_8 (access_width), &value64, access_width); } else { /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */ status = acpi_hw_read_port((acpi_io_address) address + index * ACPI_DIV_8 (access_width), &value32, access_width); value64 = (u64)value32; } } /* * Use offset style bit writes because "Index * AccessWidth" is * ensured to be less than 64-bits by acpi_hw_validate_register(). */ ACPI_SET_BITS(value, index * access_width, ACPI_MASK_BITS_ABOVE_64(access_width), value64); bit_width -= bit_width > access_width ? access_width : bit_width; index++; } ACPI_DEBUG_PRINT((ACPI_DB_IO, "Read: %8.8X%8.8X width %2d from %8.8X%8.8X (%s)\n", ACPI_FORMAT_UINT64(*value), access_width, ACPI_FORMAT_UINT64(address), acpi_ut_get_region_name(reg->space_id))); return (status); } /****************************************************************************** * * FUNCTION: acpi_hw_write * * PARAMETERS: value - Value to be written * reg - GAS register structure * * RETURN: Status * * DESCRIPTION: Write to either memory or IO space. This is a 64-bit max * version of acpi_write. * ******************************************************************************/ acpi_status acpi_hw_write(u64 value, struct acpi_generic_address *reg) { u64 address; u8 access_width; u32 bit_width; u8 bit_offset; u64 value64; u8 index; acpi_status status; ACPI_FUNCTION_NAME(hw_write); /* Validate contents of the GAS register */ status = acpi_hw_validate_register(reg, 64, &address); if (ACPI_FAILURE(status)) { return (status); } /* Convert access_width into number of bits based */ access_width = acpi_hw_get_access_bit_width(address, reg, 64); bit_width = reg->bit_offset + reg->bit_width; bit_offset = reg->bit_offset; /* * Two address spaces supported: Memory or IO. PCI_Config is * not supported here because the GAS structure is insufficient */ index = 0; while (bit_width) { /* * Use offset style bit reads because "Index * AccessWidth" is * ensured to be less than 64-bits by acpi_hw_validate_register(). */ value64 = ACPI_GET_BITS(&value, index * access_width, ACPI_MASK_BITS_ABOVE_64(access_width)); if (bit_offset >= access_width) { bit_offset -= access_width; } else { if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { status = acpi_os_write_memory((acpi_physical_address) address + index * ACPI_DIV_8 (access_width), value64, access_width); } else { /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */ status = acpi_hw_write_port((acpi_io_address) address + index * ACPI_DIV_8 (access_width), (u32)value64, access_width); } } /* * Index * access_width is ensured to be less than 32-bits by * acpi_hw_validate_register(). */ bit_width -= bit_width > access_width ? access_width : bit_width; index++; } ACPI_DEBUG_PRINT((ACPI_DB_IO, "Wrote: %8.8X%8.8X width %2d to %8.8X%8.8X (%s)\n", ACPI_FORMAT_UINT64(value), access_width, ACPI_FORMAT_UINT64(address), acpi_ut_get_region_name(reg->space_id))); return (status); } #if (!ACPI_REDUCED_HARDWARE) /******************************************************************************* * * FUNCTION: acpi_hw_clear_acpi_status * * PARAMETERS: None * * RETURN: Status * * DESCRIPTION: Clears all fixed and general purpose status bits * ******************************************************************************/ acpi_status acpi_hw_clear_acpi_status(void) { acpi_status status; acpi_cpu_flags lock_flags = 0; ACPI_FUNCTION_TRACE(hw_clear_acpi_status); ACPI_DEBUG_PRINT((ACPI_DB_IO, "About to write %04X to %8.8X%8.8X\n", ACPI_BITMASK_ALL_FIXED_STATUS, ACPI_FORMAT_UINT64(acpi_gbl_xpm1a_status.address))); lock_flags = acpi_os_acquire_raw_lock(acpi_gbl_hardware_lock); /* Clear the fixed events in PM1 A/B */ status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS, ACPI_BITMASK_ALL_FIXED_STATUS); acpi_os_release_raw_lock(acpi_gbl_hardware_lock, lock_flags); if (ACPI_FAILURE(status)) { goto exit; } /* Clear the GPE Bits in all GPE registers in all GPE blocks */ status = acpi_ev_walk_gpe_list(acpi_hw_clear_gpe_block, NULL); exit: return_ACPI_STATUS(status); } /******************************************************************************* * * FUNCTION: acpi_hw_get_bit_register_info * * PARAMETERS: register_id - Index of ACPI Register to access * * RETURN: The bitmask to be used when accessing the register * * DESCRIPTION: Map register_id into a register bitmask. * ******************************************************************************/ struct acpi_bit_register_info *acpi_hw_get_bit_register_info(u32 register_id) { ACPI_FUNCTION_ENTRY(); if (register_id > ACPI_BITREG_MAX) { ACPI_ERROR((AE_INFO, "Invalid BitRegister ID: 0x%X", register_id)); return (NULL); } return (&acpi_gbl_bit_register_info[register_id]); } /****************************************************************************** * * FUNCTION: acpi_hw_write_pm1_control * * PARAMETERS: pm1a_control - Value to be written to PM1A control * pm1b_control - Value to be written to PM1B control * * RETURN: Status * * DESCRIPTION: Write the PM1 A/B control registers. These registers are * different than the PM1 A/B status and enable registers * in that different values can be written to the A/B registers. * Most notably, the SLP_TYP bits can be different, as per the * values returned from the _Sx predefined methods. * ******************************************************************************/ acpi_status acpi_hw_write_pm1_control(u32 pm1a_control, u32 pm1b_control) { acpi_status status; ACPI_FUNCTION_TRACE(hw_write_pm1_control); status = acpi_hw_write(pm1a_control, &acpi_gbl_FADT.xpm1a_control_block); if (ACPI_FAILURE(status)) { return_ACPI_STATUS(status); } if (acpi_gbl_FADT.xpm1b_control_block.address) { status = acpi_hw_write(pm1b_control, &acpi_gbl_FADT.xpm1b_control_block); } return_ACPI_STATUS(status); } /****************************************************************************** * * FUNCTION: acpi_hw_register_read * * PARAMETERS: register_id - ACPI Register ID * return_value - Where the register value is returned * * RETURN: Status and the value read. * * DESCRIPTION: Read from the specified ACPI register * ******************************************************************************/ acpi_status acpi_hw_register_read(u32 register_id, u32 *return_value) { u32 value = 0; u64 value64; acpi_status status; ACPI_FUNCTION_TRACE(hw_register_read); switch (register_id) { case ACPI_REGISTER_PM1_STATUS: /* PM1 A/B: 16-bit access each */ status = acpi_hw_read_multiple(&value, &acpi_gbl_xpm1a_status, &acpi_gbl_xpm1b_status); break; case ACPI_REGISTER_PM1_ENABLE: /* PM1 A/B: 16-bit access each */ status = acpi_hw_read_multiple(&value, &acpi_gbl_xpm1a_enable, &acpi_gbl_xpm1b_enable); break; case ACPI_REGISTER_PM1_CONTROL: /* PM1 A/B: 16-bit access each */ status = acpi_hw_read_multiple(&value, &acpi_gbl_FADT. xpm1a_control_block, &acpi_gbl_FADT. xpm1b_control_block); /* * Zero the write-only bits. From the ACPI specification, "Hardware * Write-Only Bits": "Upon reads to registers with write-only bits, * software masks out all write-only bits." */ value &= ~ACPI_PM1_CONTROL_WRITEONLY_BITS; break; case ACPI_REGISTER_PM2_CONTROL: /* 8-bit access */ status = acpi_hw_read(&value64, &acpi_gbl_FADT.xpm2_control_block); if (ACPI_SUCCESS(status)) { value = (u32)value64; } break; case ACPI_REGISTER_PM_TIMER: /* 32-bit access */ status = acpi_hw_read(&value64, &acpi_gbl_FADT.xpm_timer_block); if (ACPI_SUCCESS(status)) { value = (u32)value64; } break; case ACPI_REGISTER_SMI_COMMAND_BLOCK: /* 8-bit access */ status = acpi_hw_read_port(acpi_gbl_FADT.smi_command, &value, 8); break; default: ACPI_ERROR((AE_INFO, "Unknown Register ID: 0x%X", register_id)); status = AE_BAD_PARAMETER; break; } if (ACPI_SUCCESS(status)) { *return_value = (u32)value; } return_ACPI_STATUS(status); } /****************************************************************************** * * FUNCTION: acpi_hw_register_write * * PARAMETERS: register_id - ACPI Register ID * value - The value to write * * RETURN: Status * * DESCRIPTION: Write to the specified ACPI register * * NOTE: In accordance with the ACPI specification, this function automatically * preserves the value of the following bits, meaning that these bits cannot be * changed via this interface: * * PM1_CONTROL[0] = SCI_EN * PM1_CONTROL[9] * PM1_STATUS[11] * * ACPI References: * 1) Hardware Ignored Bits: When software writes to a register with ignored * bit fields, it preserves the ignored bit fields * 2) SCI_EN: OSPM always preserves this bit position * ******************************************************************************/ acpi_status acpi_hw_register_write(u32 register_id, u32 value) { acpi_status status; u32 read_value; u64 read_value64; ACPI_FUNCTION_TRACE(hw_register_write); switch (register_id) { case ACPI_REGISTER_PM1_STATUS: /* PM1 A/B: 16-bit access each */ /* * Handle the "ignored" bit in PM1 Status. According to the ACPI * specification, ignored bits are to be preserved when writing. * Normally, this would mean a read/modify/write sequence. However, * preserving a bit in the status register is different. Writing a * one clears the status, and writing a zero preserves the status. * Therefore, we must always write zero to the ignored bit. * * This behavior is clarified in the ACPI 4.0 specification. */ value &= ~ACPI_PM1_STATUS_PRESERVED_BITS; status = acpi_hw_write_multiple(value, &acpi_gbl_xpm1a_status, &acpi_gbl_xpm1b_status); break; case ACPI_REGISTER_PM1_ENABLE: /* PM1 A/B: 16-bit access each */ status = acpi_hw_write_multiple(value, &acpi_gbl_xpm1a_enable, &acpi_gbl_xpm1b_enable); break; case ACPI_REGISTER_PM1_CONTROL: /* PM1 A/B: 16-bit access each */ /* * Perform a read first to preserve certain bits (per ACPI spec) * Note: This includes SCI_EN, we never want to change this bit */ status = acpi_hw_read_multiple(&read_value, &acpi_gbl_FADT. xpm1a_control_block, &acpi_gbl_FADT. xpm1b_control_block); if (ACPI_FAILURE(status)) { goto exit; } /* Insert the bits to be preserved */ ACPI_INSERT_BITS(value, ACPI_PM1_CONTROL_PRESERVED_BITS, read_value); /* Now we can write the data */ status = acpi_hw_write_multiple(value, &acpi_gbl_FADT. xpm1a_control_block, &acpi_gbl_FADT. xpm1b_control_block); break; case ACPI_REGISTER_PM2_CONTROL: /* 8-bit access */ /* * For control registers, all reserved bits must be preserved, * as per the ACPI spec. */ status = acpi_hw_read(&read_value64, &acpi_gbl_FADT.xpm2_control_block); if (ACPI_FAILURE(status)) { goto exit; } read_value = (u32)read_value64; /* Insert the bits to be preserved */ ACPI_INSERT_BITS(value, ACPI_PM2_CONTROL_PRESERVED_BITS, read_value); status = acpi_hw_write(value, &acpi_gbl_FADT.xpm2_control_block); break; case ACPI_REGISTER_PM_TIMER: /* 32-bit access */ status = acpi_hw_write(value, &acpi_gbl_FADT.xpm_timer_block); break; case ACPI_REGISTER_SMI_COMMAND_BLOCK: /* 8-bit access */ /* SMI_CMD is currently always in IO space */ status = acpi_hw_write_port(acpi_gbl_FADT.smi_command, value, 8); break; default: ACPI_ERROR((AE_INFO, "Unknown Register ID: 0x%X", register_id)); status = AE_BAD_PARAMETER; break; } exit: return_ACPI_STATUS(status); } /****************************************************************************** * * FUNCTION: acpi_hw_read_multiple * * PARAMETERS: value - Where the register value is returned * register_a - First ACPI register (required) * register_b - Second ACPI register (optional) * * RETURN: Status * * DESCRIPTION: Read from the specified two-part ACPI register (such as PM1 A/B) * ******************************************************************************/ static acpi_status acpi_hw_read_multiple(u32 *value, struct acpi_generic_address *register_a, struct acpi_generic_address *register_b) { u32 value_a = 0; u32 value_b = 0; u64 value64; acpi_status status; /* The first register is always required */ status = acpi_hw_read(&value64, register_a); if (ACPI_FAILURE(status)) { return (status); } value_a = (u32)value64; /* Second register is optional */ if (register_b->address) { status = acpi_hw_read(&value64, register_b); if (ACPI_FAILURE(status)) { return (status); } value_b = (u32)value64; } /* * OR the two return values together. No shifting or masking is necessary, * because of how the PM1 registers are defined in the ACPI specification: * * "Although the bits can be split between the two register blocks (each * register block has a unique pointer within the FADT), the bit positions * are maintained. The register block with unimplemented bits (that is, * those implemented in the other register block) always returns zeros, * and writes have no side effects" */ *value = (value_a | value_b); return (AE_OK); } /****************************************************************************** * * FUNCTION: acpi_hw_write_multiple * * PARAMETERS: value - The value to write * register_a - First ACPI register (required) * register_b - Second ACPI register (optional) * * RETURN: Status * * DESCRIPTION: Write to the specified two-part ACPI register (such as PM1 A/B) * ******************************************************************************/ static acpi_status acpi_hw_write_multiple(u32 value, struct acpi_generic_address *register_a, struct acpi_generic_address *register_b) { acpi_status status; /* The first register is always required */ status = acpi_hw_write(value, register_a); if (ACPI_FAILURE(status)) { return (status); } /* * Second register is optional * * No bit shifting or clearing is necessary, because of how the PM1 * registers are defined in the ACPI specification: * * "Although the bits can be split between the two register blocks (each * register block has a unique pointer within the FADT), the bit positions * are maintained. The register block with unimplemented bits (that is, * those implemented in the other register block) always returns zeros, * and writes have no side effects" */ if (register_b->address) { status = acpi_hw_write(value, register_b); } return (status); } #endif /* !ACPI_REDUCED_HARDWARE */
