diff options
Diffstat (limited to 'drivers/acpi/acpica/exfldio.c')
| -rw-r--r-- | drivers/acpi/acpica/exfldio.c | 967 |
1 files changed, 967 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/exfldio.c b/drivers/acpi/acpica/exfldio.c new file mode 100644 index 000000000..516994133 --- /dev/null +++ b/drivers/acpi/acpica/exfldio.c @@ -0,0 +1,967 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 +/****************************************************************************** + * + * Module Name: exfldio - Aml Field I/O + * + * Copyright (C) 2000 - 2018, Intel Corp. + * + *****************************************************************************/ + +#include <acpi/acpi.h> +#include "accommon.h" +#include "acinterp.h" +#include "amlcode.h" +#include "acevents.h" +#include "acdispat.h" + +#define _COMPONENT ACPI_EXECUTER +ACPI_MODULE_NAME("exfldio") + +/* Local prototypes */ +static acpi_status +acpi_ex_field_datum_io(union acpi_operand_object *obj_desc, + u32 field_datum_byte_offset, u64 *value, u32 read_write); + +static u8 +acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value); + +static acpi_status +acpi_ex_setup_region(union acpi_operand_object *obj_desc, + u32 field_datum_byte_offset); + +/******************************************************************************* + * + * FUNCTION: acpi_ex_setup_region + * + * PARAMETERS: obj_desc - Field to be read or written + * field_datum_byte_offset - Byte offset of this datum within the + * parent field + * + * RETURN: Status + * + * DESCRIPTION: Common processing for acpi_ex_extract_from_field and + * acpi_ex_insert_into_field. Initialize the Region if necessary and + * validate the request. + * + ******************************************************************************/ + +static acpi_status +acpi_ex_setup_region(union acpi_operand_object *obj_desc, + u32 field_datum_byte_offset) +{ + acpi_status status = AE_OK; + union acpi_operand_object *rgn_desc; + u8 space_id; + + ACPI_FUNCTION_TRACE_U32(ex_setup_region, field_datum_byte_offset); + + rgn_desc = obj_desc->common_field.region_obj; + + /* We must have a valid region */ + + if (rgn_desc->common.type != ACPI_TYPE_REGION) { + ACPI_ERROR((AE_INFO, "Needed Region, found type 0x%X (%s)", + rgn_desc->common.type, + acpi_ut_get_object_type_name(rgn_desc))); + + return_ACPI_STATUS(AE_AML_OPERAND_TYPE); + } + + space_id = rgn_desc->region.space_id; + + /* Validate the Space ID */ + + if (!acpi_is_valid_space_id(space_id)) { + ACPI_ERROR((AE_INFO, + "Invalid/unknown Address Space ID: 0x%2.2X", + space_id)); + return_ACPI_STATUS(AE_AML_INVALID_SPACE_ID); + } + + /* + * If the Region Address and Length have not been previously evaluated, + * evaluate them now and save the results. + */ + if (!(rgn_desc->common.flags & AOPOBJ_DATA_VALID)) { + status = acpi_ds_get_region_arguments(rgn_desc); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + } + + /* + * Exit now for SMBus, GSBus or IPMI address space, it has a non-linear + * address space and the request cannot be directly validated + */ + if (space_id == ACPI_ADR_SPACE_SMBUS || + space_id == ACPI_ADR_SPACE_GSBUS || + space_id == ACPI_ADR_SPACE_IPMI) { + + /* SMBus or IPMI has a non-linear address space */ + + return_ACPI_STATUS(AE_OK); + } +#ifdef ACPI_UNDER_DEVELOPMENT + /* + * If the Field access is any_acc, we can now compute the optimal + * access (because we know know the length of the parent region) + */ + if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) { + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + } +#endif + + /* + * Validate the request. The entire request from the byte offset for a + * length of one field datum (access width) must fit within the region. + * (Region length is specified in bytes) + */ + if (rgn_desc->region.length < + (obj_desc->common_field.base_byte_offset + field_datum_byte_offset + + obj_desc->common_field.access_byte_width)) { + if (acpi_gbl_enable_interpreter_slack) { + /* + * Slack mode only: We will go ahead and allow access to this + * field if it is within the region length rounded up to the next + * access width boundary. acpi_size cast for 64-bit compile. + */ + if (ACPI_ROUND_UP(rgn_desc->region.length, + obj_desc->common_field. + access_byte_width) >= + ((acpi_size)obj_desc->common_field. + base_byte_offset + + obj_desc->common_field.access_byte_width + + field_datum_byte_offset)) { + return_ACPI_STATUS(AE_OK); + } + } + + if (rgn_desc->region.length < + obj_desc->common_field.access_byte_width) { + /* + * This is the case where the access_type (acc_word, etc.) is wider + * than the region itself. For example, a region of length one + * byte, and a field with Dword access specified. + */ + ACPI_ERROR((AE_INFO, + "Field [%4.4s] access width (%u bytes) " + "too large for region [%4.4s] (length %u)", + acpi_ut_get_node_name(obj_desc-> + common_field.node), + obj_desc->common_field.access_byte_width, + acpi_ut_get_node_name(rgn_desc->region. + node), + rgn_desc->region.length)); + } + + /* + * Offset rounded up to next multiple of field width + * exceeds region length, indicate an error + */ + ACPI_ERROR((AE_INFO, + "Field [%4.4s] Base+Offset+Width %u+%u+%u " + "is beyond end of region [%4.4s] (length %u)", + acpi_ut_get_node_name(obj_desc->common_field.node), + obj_desc->common_field.base_byte_offset, + field_datum_byte_offset, + obj_desc->common_field.access_byte_width, + acpi_ut_get_node_name(rgn_desc->region.node), + rgn_desc->region.length)); + + return_ACPI_STATUS(AE_AML_REGION_LIMIT); + } + + return_ACPI_STATUS(AE_OK); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ex_access_region + * + * PARAMETERS: obj_desc - Field to be read + * field_datum_byte_offset - Byte offset of this datum within the + * parent field + * value - Where to store value (must at least + * 64 bits) + * function - Read or Write flag plus other region- + * dependent flags + * + * RETURN: Status + * + * DESCRIPTION: Read or Write a single field datum to an Operation Region. + * + ******************************************************************************/ + +acpi_status +acpi_ex_access_region(union acpi_operand_object *obj_desc, + u32 field_datum_byte_offset, u64 *value, u32 function) +{ + acpi_status status; + union acpi_operand_object *rgn_desc; + u32 region_offset; + + ACPI_FUNCTION_TRACE(ex_access_region); + + /* + * Ensure that the region operands are fully evaluated and verify + * the validity of the request + */ + status = acpi_ex_setup_region(obj_desc, field_datum_byte_offset); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + + /* + * The physical address of this field datum is: + * + * 1) The base of the region, plus + * 2) The base offset of the field, plus + * 3) The current offset into the field + */ + rgn_desc = obj_desc->common_field.region_obj; + region_offset = + obj_desc->common_field.base_byte_offset + field_datum_byte_offset; + + if ((function & ACPI_IO_MASK) == ACPI_READ) { + ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[READ]")); + } else { + ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[WRITE]")); + } + + ACPI_DEBUG_PRINT_RAW((ACPI_DB_BFIELD, + " Region [%s:%X], Width %X, ByteBase %X, Offset %X at %8.8X%8.8X\n", + acpi_ut_get_region_name(rgn_desc->region. + space_id), + rgn_desc->region.space_id, + obj_desc->common_field.access_byte_width, + obj_desc->common_field.base_byte_offset, + field_datum_byte_offset, + ACPI_FORMAT_UINT64(rgn_desc->region.address + + region_offset))); + + /* Invoke the appropriate address_space/op_region handler */ + + status = acpi_ev_address_space_dispatch(rgn_desc, obj_desc, + function, region_offset, + ACPI_MUL_8(obj_desc-> + common_field. + access_byte_width), + value); + + if (ACPI_FAILURE(status)) { + if (status == AE_NOT_IMPLEMENTED) { + ACPI_ERROR((AE_INFO, + "Region %s (ID=%u) not implemented", + acpi_ut_get_region_name(rgn_desc->region. + space_id), + rgn_desc->region.space_id)); + } else if (status == AE_NOT_EXIST) { + ACPI_ERROR((AE_INFO, + "Region %s (ID=%u) has no handler", + acpi_ut_get_region_name(rgn_desc->region. + space_id), + rgn_desc->region.space_id)); + } + } + + return_ACPI_STATUS(status); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ex_register_overflow + * + * PARAMETERS: obj_desc - Register(Field) to be written + * value - Value to be stored + * + * RETURN: TRUE if value overflows the field, FALSE otherwise + * + * DESCRIPTION: Check if a value is out of range of the field being written. + * Used to check if the values written to Index and Bank registers + * are out of range. Normally, the value is simply truncated + * to fit the field, but this case is most likely a serious + * coding error in the ASL. + * + ******************************************************************************/ + +static u8 +acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value) +{ + + if (obj_desc->common_field.bit_length >= ACPI_INTEGER_BIT_SIZE) { + /* + * The field is large enough to hold the maximum integer, so we can + * never overflow it. + */ + return (FALSE); + } + + if (value >= ((u64) 1 << obj_desc->common_field.bit_length)) { + /* + * The Value is larger than the maximum value that can fit into + * the register. + */ + ACPI_ERROR((AE_INFO, + "Index value 0x%8.8X%8.8X overflows field width 0x%X", + ACPI_FORMAT_UINT64(value), + obj_desc->common_field.bit_length)); + + return (TRUE); + } + + /* The Value will fit into the field with no truncation */ + + return (FALSE); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ex_field_datum_io + * + * PARAMETERS: obj_desc - Field to be read + * field_datum_byte_offset - Byte offset of this datum within the + * parent field + * value - Where to store value (must be 64 bits) + * read_write - Read or Write flag + * + * RETURN: Status + * + * DESCRIPTION: Read or Write a single datum of a field. The field_type is + * demultiplexed here to handle the different types of fields + * (buffer_field, region_field, index_field, bank_field) + * + ******************************************************************************/ + +static acpi_status +acpi_ex_field_datum_io(union acpi_operand_object *obj_desc, + u32 field_datum_byte_offset, u64 *value, u32 read_write) +{ + acpi_status status; + u64 local_value; + + ACPI_FUNCTION_TRACE_U32(ex_field_datum_io, field_datum_byte_offset); + + if (read_write == ACPI_READ) { + if (!value) { + local_value = 0; + + /* To support reads without saving return value */ + value = &local_value; + } + + /* Clear the entire return buffer first, [Very Important!] */ + + *value = 0; + } + + /* + * The four types of fields are: + * + * buffer_field - Read/write from/to a Buffer + * region_field - Read/write from/to a Operation Region. + * bank_field - Write to a Bank Register, then read/write from/to an + * operation_region + * index_field - Write to an Index Register, then read/write from/to a + * Data Register + */ + switch (obj_desc->common.type) { + case ACPI_TYPE_BUFFER_FIELD: + /* + * If the buffer_field arguments have not been previously evaluated, + * evaluate them now and save the results. + */ + if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) { + status = acpi_ds_get_buffer_field_arguments(obj_desc); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + } + + if (read_write == ACPI_READ) { + /* + * Copy the data from the source buffer. + * Length is the field width in bytes. + */ + memcpy(value, + (obj_desc->buffer_field.buffer_obj)->buffer. + pointer + + obj_desc->buffer_field.base_byte_offset + + field_datum_byte_offset, + obj_desc->common_field.access_byte_width); + } else { + /* + * Copy the data to the target buffer. + * Length is the field width in bytes. + */ + memcpy((obj_desc->buffer_field.buffer_obj)->buffer. + pointer + + obj_desc->buffer_field.base_byte_offset + + field_datum_byte_offset, value, + obj_desc->common_field.access_byte_width); + } + + status = AE_OK; + break; + + case ACPI_TYPE_LOCAL_BANK_FIELD: + /* + * Ensure that the bank_value is not beyond the capacity of + * the register + */ + if (acpi_ex_register_overflow(obj_desc->bank_field.bank_obj, + (u64) obj_desc->bank_field. + value)) { + return_ACPI_STATUS(AE_AML_REGISTER_LIMIT); + } + + /* + * For bank_fields, we must write the bank_value to the bank_register + * (itself a region_field) before we can access the data. + */ + status = + acpi_ex_insert_into_field(obj_desc->bank_field.bank_obj, + &obj_desc->bank_field.value, + sizeof(obj_desc->bank_field. + value)); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + + /* + * Now that the Bank has been selected, fall through to the + * region_field case and write the datum to the Operation Region + */ + + /*lint -fallthrough */ + + case ACPI_TYPE_LOCAL_REGION_FIELD: + /* + * For simple region_fields, we just directly access the owning + * Operation Region. + */ + status = + acpi_ex_access_region(obj_desc, field_datum_byte_offset, + value, read_write); + break; + + case ACPI_TYPE_LOCAL_INDEX_FIELD: + /* + * Ensure that the index_value is not beyond the capacity of + * the register + */ + if (acpi_ex_register_overflow(obj_desc->index_field.index_obj, + (u64) obj_desc->index_field. + value)) { + return_ACPI_STATUS(AE_AML_REGISTER_LIMIT); + } + + /* Write the index value to the index_register (itself a region_field) */ + + field_datum_byte_offset += obj_desc->index_field.value; + + ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, + "Write to Index Register: Value %8.8X\n", + field_datum_byte_offset)); + + status = + acpi_ex_insert_into_field(obj_desc->index_field.index_obj, + &field_datum_byte_offset, + sizeof(field_datum_byte_offset)); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + + if (read_write == ACPI_READ) { + + /* Read the datum from the data_register */ + + ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, + "Read from Data Register\n")); + + status = + acpi_ex_extract_from_field(obj_desc->index_field. + data_obj, value, + sizeof(u64)); + } else { + /* Write the datum to the data_register */ + + ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, + "Write to Data Register: Value %8.8X%8.8X\n", + ACPI_FORMAT_UINT64(*value))); + + status = + acpi_ex_insert_into_field(obj_desc->index_field. + data_obj, value, + sizeof(u64)); + } + break; + + default: + + ACPI_ERROR((AE_INFO, "Wrong object type in field I/O %u", + obj_desc->common.type)); + status = AE_AML_INTERNAL; + break; + } + + if (ACPI_SUCCESS(status)) { + if (read_write == ACPI_READ) { + ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, + "Value Read %8.8X%8.8X, Width %u\n", + ACPI_FORMAT_UINT64(*value), + obj_desc->common_field. + access_byte_width)); + } else { + ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, + "Value Written %8.8X%8.8X, Width %u\n", + ACPI_FORMAT_UINT64(*value), + obj_desc->common_field. + access_byte_width)); + } + } + + return_ACPI_STATUS(status); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ex_write_with_update_rule + * + * PARAMETERS: obj_desc - Field to be written + * mask - bitmask within field datum + * field_value - Value to write + * field_datum_byte_offset - Offset of datum within field + * + * RETURN: Status + * + * DESCRIPTION: Apply the field update rule to a field write + * + ******************************************************************************/ + +acpi_status +acpi_ex_write_with_update_rule(union acpi_operand_object *obj_desc, + u64 mask, + u64 field_value, u32 field_datum_byte_offset) +{ + acpi_status status = AE_OK; + u64 merged_value; + u64 current_value; + + ACPI_FUNCTION_TRACE_U32(ex_write_with_update_rule, mask); + + /* Start with the new bits */ + + merged_value = field_value; + + /* If the mask is all ones, we don't need to worry about the update rule */ + + if (mask != ACPI_UINT64_MAX) { + + /* Decode the update rule */ + + switch (obj_desc->common_field. + field_flags & AML_FIELD_UPDATE_RULE_MASK) { + case AML_FIELD_UPDATE_PRESERVE: + /* + * Check if update rule needs to be applied (not if mask is all + * ones) The left shift drops the bits we want to ignore. + */ + if ((~mask << (ACPI_MUL_8(sizeof(mask)) - + ACPI_MUL_8(obj_desc->common_field. + access_byte_width))) != 0) { + /* + * Read the current contents of the byte/word/dword containing + * the field, and merge with the new field value. + */ + status = + acpi_ex_field_datum_io(obj_desc, + field_datum_byte_offset, + ¤t_value, + ACPI_READ); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + + merged_value |= (current_value & ~mask); + } + break; + + case AML_FIELD_UPDATE_WRITE_AS_ONES: + + /* Set positions outside the field to all ones */ + + merged_value |= ~mask; + break; + + case AML_FIELD_UPDATE_WRITE_AS_ZEROS: + + /* Set positions outside the field to all zeros */ + + merged_value &= mask; + break; + + default: + + ACPI_ERROR((AE_INFO, + "Unknown UpdateRule value: 0x%X", + (obj_desc->common_field.field_flags & + AML_FIELD_UPDATE_RULE_MASK))); + return_ACPI_STATUS(AE_AML_OPERAND_VALUE); + } + } + + ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, + "Mask %8.8X%8.8X, DatumOffset %X, Width %X, " + "Value %8.8X%8.8X, MergedValue %8.8X%8.8X\n", + ACPI_FORMAT_UINT64(mask), + field_datum_byte_offset, + obj_desc->common_field.access_byte_width, + ACPI_FORMAT_UINT64(field_value), + ACPI_FORMAT_UINT64(merged_value))); + + /* Write the merged value */ + + status = + acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset, + &merged_value, ACPI_WRITE); + + return_ACPI_STATUS(status); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ex_extract_from_field + * + * PARAMETERS: obj_desc - Field to be read + * buffer - Where to store the field data + * buffer_length - Length of Buffer + * + * RETURN: Status + * + * DESCRIPTION: Retrieve the current value of the given field + * + ******************************************************************************/ + +acpi_status +acpi_ex_extract_from_field(union acpi_operand_object *obj_desc, + void *buffer, u32 buffer_length) +{ + acpi_status status; + u64 raw_datum; + u64 merged_datum; + u32 field_offset = 0; + u32 buffer_offset = 0; + u32 buffer_tail_bits; + u32 datum_count; + u32 field_datum_count; + u32 access_bit_width; + u32 i; + + ACPI_FUNCTION_TRACE(ex_extract_from_field); + + /* Validate target buffer and clear it */ + + if (buffer_length < + ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length)) { + ACPI_ERROR((AE_INFO, + "Field size %u (bits) is too large for buffer (%u)", + obj_desc->common_field.bit_length, buffer_length)); + + return_ACPI_STATUS(AE_BUFFER_OVERFLOW); + } + + memset(buffer, 0, buffer_length); + access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width); + + /* Handle the simple case here */ + + if ((obj_desc->common_field.start_field_bit_offset == 0) && + (obj_desc->common_field.bit_length == access_bit_width)) { + if (buffer_length >= sizeof(u64)) { + status = + acpi_ex_field_datum_io(obj_desc, 0, buffer, + ACPI_READ); + } else { + /* Use raw_datum (u64) to handle buffers < 64 bits */ + + status = + acpi_ex_field_datum_io(obj_desc, 0, &raw_datum, + ACPI_READ); + memcpy(buffer, &raw_datum, buffer_length); + } + + return_ACPI_STATUS(status); + } + +/* TBD: Move to common setup code */ + + /* Field algorithm is limited to sizeof(u64), truncate if needed */ + + if (obj_desc->common_field.access_byte_width > sizeof(u64)) { + obj_desc->common_field.access_byte_width = sizeof(u64); + access_bit_width = sizeof(u64) * 8; + } + + /* Compute the number of datums (access width data items) */ + + datum_count = + ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length, + access_bit_width); + + field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length + + obj_desc->common_field. + start_field_bit_offset, + access_bit_width); + + /* Priming read from the field */ + + status = + acpi_ex_field_datum_io(obj_desc, field_offset, &raw_datum, + ACPI_READ); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + merged_datum = + raw_datum >> obj_desc->common_field.start_field_bit_offset; + + /* Read the rest of the field */ + + for (i = 1; i < field_datum_count; i++) { + + /* Get next input datum from the field */ + + field_offset += obj_desc->common_field.access_byte_width; + status = + acpi_ex_field_datum_io(obj_desc, field_offset, &raw_datum, + ACPI_READ); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + + /* + * Merge with previous datum if necessary. + * + * Note: Before the shift, check if the shift value will be larger than + * the integer size. If so, there is no need to perform the operation. + * This avoids the differences in behavior between different compilers + * concerning shift values larger than the target data width. + */ + if (access_bit_width - + obj_desc->common_field.start_field_bit_offset < + ACPI_INTEGER_BIT_SIZE) { + merged_datum |= + raw_datum << (access_bit_width - + obj_desc->common_field. + start_field_bit_offset); + } + + if (i == datum_count) { + break; + } + + /* Write merged datum to target buffer */ + + memcpy(((char *)buffer) + buffer_offset, &merged_datum, + ACPI_MIN(obj_desc->common_field.access_byte_width, + buffer_length - buffer_offset)); + + buffer_offset += obj_desc->common_field.access_byte_width; + merged_datum = + raw_datum >> obj_desc->common_field.start_field_bit_offset; + } + + /* Mask off any extra bits in the last datum */ + + buffer_tail_bits = obj_desc->common_field.bit_length % access_bit_width; + if (buffer_tail_bits) { + merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits); + } + + /* Write the last datum to the buffer */ + + memcpy(((char *)buffer) + buffer_offset, &merged_datum, + ACPI_MIN(obj_desc->common_field.access_byte_width, + buffer_length - buffer_offset)); + + return_ACPI_STATUS(AE_OK); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ex_insert_into_field + * + * PARAMETERS: obj_desc - Field to be written + * buffer - Data to be written + * buffer_length - Length of Buffer + * + * RETURN: Status + * + * DESCRIPTION: Store the Buffer contents into the given field + * + ******************************************************************************/ + +acpi_status +acpi_ex_insert_into_field(union acpi_operand_object *obj_desc, + void *buffer, u32 buffer_length) +{ + void *new_buffer; + acpi_status status; + u64 mask; + u64 width_mask; + u64 merged_datum; + u64 raw_datum = 0; + u32 field_offset = 0; + u32 buffer_offset = 0; + u32 buffer_tail_bits; + u32 datum_count; + u32 field_datum_count; + u32 access_bit_width; + u32 required_length; + u32 i; + + ACPI_FUNCTION_TRACE(ex_insert_into_field); + + /* Validate input buffer */ + + new_buffer = NULL; + required_length = + ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length); + + /* + * We must have a buffer that is at least as long as the field + * we are writing to. This is because individual fields are + * indivisible and partial writes are not supported -- as per + * the ACPI specification. + */ + if (buffer_length < required_length) { + + /* We need to create a new buffer */ + + new_buffer = ACPI_ALLOCATE_ZEROED(required_length); + if (!new_buffer) { + return_ACPI_STATUS(AE_NO_MEMORY); + } + + /* + * Copy the original data to the new buffer, starting + * at Byte zero. All unused (upper) bytes of the + * buffer will be 0. + */ + memcpy((char *)new_buffer, (char *)buffer, buffer_length); + buffer = new_buffer; + buffer_length = required_length; + } + +/* TBD: Move to common setup code */ + + /* Algo is limited to sizeof(u64), so cut the access_byte_width */ + if (obj_desc->common_field.access_byte_width > sizeof(u64)) { + obj_desc->common_field.access_byte_width = sizeof(u64); + } + + access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width); + + /* Create the bitmasks used for bit insertion */ + + width_mask = ACPI_MASK_BITS_ABOVE_64(access_bit_width); + mask = width_mask & + ACPI_MASK_BITS_BELOW(obj_desc->common_field.start_field_bit_offset); + + /* Compute the number of datums (access width data items) */ + + datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length, + access_bit_width); + + field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length + + obj_desc->common_field. + start_field_bit_offset, + access_bit_width); + + /* Get initial Datum from the input buffer */ + + memcpy(&raw_datum, buffer, + ACPI_MIN(obj_desc->common_field.access_byte_width, + buffer_length - buffer_offset)); + + merged_datum = + raw_datum << obj_desc->common_field.start_field_bit_offset; + + /* Write the entire field */ + + for (i = 1; i < field_datum_count; i++) { + + /* Write merged datum to the target field */ + + merged_datum &= mask; + status = + acpi_ex_write_with_update_rule(obj_desc, mask, merged_datum, + field_offset); + if (ACPI_FAILURE(status)) { + goto exit; + } + + field_offset += obj_desc->common_field.access_byte_width; + + /* + * Start new output datum by merging with previous input datum + * if necessary. + * + * Note: Before the shift, check if the shift value will be larger than + * the integer size. If so, there is no need to perform the operation. + * This avoids the differences in behavior between different compilers + * concerning shift values larger than the target data width. + */ + if ((access_bit_width - + obj_desc->common_field.start_field_bit_offset) < + ACPI_INTEGER_BIT_SIZE) { + merged_datum = + raw_datum >> (access_bit_width - + obj_desc->common_field. + start_field_bit_offset); + } else { + merged_datum = 0; + } + + mask = width_mask; + + if (i == datum_count) { + break; + } + + /* Get the next input datum from the buffer */ + + buffer_offset += obj_desc->common_field.access_byte_width; + memcpy(&raw_datum, ((char *)buffer) + buffer_offset, + ACPI_MIN(obj_desc->common_field.access_byte_width, + buffer_length - buffer_offset)); + + merged_datum |= + raw_datum << obj_desc->common_field.start_field_bit_offset; + } + + /* Mask off any extra bits in the last datum */ + + buffer_tail_bits = (obj_desc->common_field.bit_length + + obj_desc->common_field.start_field_bit_offset) % + access_bit_width; + if (buffer_tail_bits) { + mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits); + } + + /* Write the last datum to the field */ + + merged_datum &= mask; + status = + acpi_ex_write_with_update_rule(obj_desc, mask, merged_datum, + field_offset); + +exit: + /* Free temporary buffer if we used one */ + + if (new_buffer) { + ACPI_FREE(new_buffer); + } + return_ACPI_STATUS(status); +} |