diff options
Diffstat (limited to 'drivers/acpi/executer/exfldio.c')
| -rw-r--r-- | drivers/acpi/executer/exfldio.c | 835 |
1 files changed, 835 insertions, 0 deletions
diff --git a/drivers/acpi/executer/exfldio.c b/drivers/acpi/executer/exfldio.c new file mode 100644 index 00000000000..9d0f9d2e906 --- /dev/null +++ b/drivers/acpi/executer/exfldio.c @@ -0,0 +1,835 @@ +/****************************************************************************** + * + * Module Name: exfldio - Aml Field I/O + * + *****************************************************************************/ + +/* + * Copyright (C) 2000 - 2005, R. Byron Moore + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions, and the following disclaimer, + * without modification. + * 2. Redistributions in binary form must reproduce at minimum a disclaimer + * substantially similar to the "NO WARRANTY" disclaimer below + * ("Disclaimer") and any redistribution must be conditioned upon + * including a substantially similar Disclaimer requirement for further + * binary redistribution. + * 3. Neither the names of the above-listed copyright holders nor the names + * of any contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * Alternatively, this software may be distributed under the terms of the + * GNU General Public License ("GPL") version 2 as published by the Free + * Software Foundation. + * + * NO WARRANTY + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING + * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGES. + */ + + +#include <acpi/acpi.h> +#include <acpi/acinterp.h> +#include <acpi/amlcode.h> +#include <acpi/acevents.h> +#include <acpi/acdispat.h> + + +#define _COMPONENT ACPI_EXECUTER + ACPI_MODULE_NAME ("exfldio") + + +/******************************************************************************* + * + * 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. + * + ******************************************************************************/ + +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; + + + 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 (ACPI_GET_OBJECT_TYPE (rgn_desc) != ACPI_TYPE_REGION) { + ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Needed Region, found type %X (%s)\n", + ACPI_GET_OBJECT_TYPE (rgn_desc), + acpi_ut_get_object_type_name (rgn_desc))); + + return_ACPI_STATUS (AE_AML_OPERAND_TYPE); + } + + /* + * 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); + } + } + + if (rgn_desc->region.space_id == ACPI_ADR_SPACE_SMBUS) { + /* SMBus 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. + */ + if (ACPI_ROUND_UP (rgn_desc->region.length, + obj_desc->common_field.access_byte_width) >= + (obj_desc->common_field.base_byte_offset + + (acpi_native_uint) 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_DEBUG_PRINT ((ACPI_DB_ERROR, + "Field [%4.4s] access width (%d bytes) too large for region [%4.4s] (length %X)\n", + 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_DEBUG_PRINT ((ACPI_DB_ERROR, + "Field [%4.4s] Base+Offset+Width %X+%X+%X is beyond end of region [%4.4s] (length %X)\n", + 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 + * the size of acpi_integer) + * 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, + acpi_integer *value, + u32 function) +{ + acpi_status status; + union acpi_operand_object *rgn_desc; + acpi_physical_address address; + + + 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; + address = rgn_desc->region.address + + 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, byte_base %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 (address))); + + /* Invoke the appropriate address_space/op_region handler */ + + status = acpi_ev_address_space_dispatch (rgn_desc, function, + address, ACPI_MUL_8 (obj_desc->common_field.access_byte_width), value); + + if (ACPI_FAILURE (status)) { + if (status == AE_NOT_IMPLEMENTED) { + ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, + "Region %s(%X) not implemented\n", + acpi_ut_get_region_name (rgn_desc->region.space_id), + rgn_desc->region.space_id)); + } + else if (status == AE_NOT_EXIST) { + ACPI_REPORT_ERROR (( + "Region %s(%X) has no handler\n", + 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. + * + ******************************************************************************/ + +u8 +acpi_ex_register_overflow ( + union acpi_operand_object *obj_desc, + acpi_integer 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 >= ((acpi_integer) 1 << obj_desc->common_field.bit_length)) { + /* + * The Value is larger than the maximum value that can fit into + * the register. + */ + 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) + * + ******************************************************************************/ + +acpi_status +acpi_ex_field_datum_io ( + union acpi_operand_object *obj_desc, + u32 field_datum_byte_offset, + acpi_integer *value, + u32 read_write) +{ + acpi_status status; + acpi_integer local_value; + + + ACPI_FUNCTION_TRACE_U32 ("ex_field_datum_io", field_datum_byte_offset); + + + if (read_write == ACPI_READ) { + if (!value) { + local_value = 0; + value = &local_value; /* To support reads without saving return 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 op_region + * index_field - Write to an Index Register, then read/write from/to a Data Register + */ + switch (ACPI_GET_OBJECT_TYPE (obj_desc)) { + 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. + */ + ACPI_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. + */ + ACPI_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, + (acpi_integer) 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, + (acpi_integer) 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); + } + + ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD, + "I/O to Data Register: value_ptr %p\n", + value)); + + if (read_write == ACPI_READ) { + /* Read the datum from the data_register */ + + status = acpi_ex_extract_from_field (obj_desc->index_field.data_obj, + value, sizeof (acpi_integer)); + } + else { + /* Write the datum to the data_register */ + + status = acpi_ex_insert_into_field (obj_desc->index_field.data_obj, + value, sizeof (acpi_integer)); + } + break; + + + default: + + ACPI_REPORT_ERROR (("Wrong object type in field I/O %X\n", + ACPI_GET_OBJECT_TYPE (obj_desc))); + 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 %d\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 %d\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 set + * Value - Value to store + * + * 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, + acpi_integer mask, + acpi_integer field_value, + u32 field_datum_byte_offset) +{ + acpi_status status = AE_OK; + acpi_integer merged_value; + acpi_integer 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_INTEGER_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_DEBUG_PRINT ((ACPI_DB_ERROR, + "write_with_update_rule: Unknown update_rule setting: %X\n", + (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, datum_offset %X, Width %X, Value %8.8X%8.8X, merged_value %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; + acpi_integer raw_datum; + acpi_integer merged_datum; + u32 field_offset = 0; + u32 buffer_offset = 0; + u32 buffer_tail_bits; + u32 datum_count; + u32 field_datum_count; + 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_DEBUG_PRINT ((ACPI_DB_ERROR, + "Field size %X (bits) is too large for buffer (%X)\n", + obj_desc->common_field.bit_length, buffer_length)); + + return_ACPI_STATUS (AE_BUFFER_OVERFLOW); + } + ACPI_MEMSET (buffer, 0, buffer_length); + + /* Compute the number of datums (access width data items) */ + + datum_count = ACPI_ROUND_UP_TO ( + obj_desc->common_field.bit_length, + obj_desc->common_field.access_bit_width); + field_datum_count = ACPI_ROUND_UP_TO ( + obj_desc->common_field.bit_length + + obj_desc->common_field.start_field_bit_offset, + obj_desc->common_field.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 */ + + merged_datum |= raw_datum << + (obj_desc->common_field.access_bit_width - obj_desc->common_field.start_field_bit_offset); + + if (i == datum_count) { + break; + } + + /* Write merged datum to target buffer */ + + ACPI_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 % obj_desc->common_field.access_bit_width; + if (buffer_tail_bits) { + merged_datum &= ACPI_MASK_BITS_ABOVE (buffer_tail_bits); + } + + /* Write the last datum to the buffer */ + + ACPI_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) +{ + acpi_status status; + acpi_integer mask; + acpi_integer merged_datum; + acpi_integer raw_datum = 0; + u32 field_offset = 0; + u32 buffer_offset = 0; + u32 buffer_tail_bits; + u32 datum_count; + u32 field_datum_count; + u32 i; + + + ACPI_FUNCTION_TRACE ("ex_insert_into_field"); + + + /* Validate input buffer */ + + if (buffer_length < ACPI_ROUND_BITS_UP_TO_BYTES ( + obj_desc->common_field.bit_length)) { + ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, + "Field size %X (bits) is too large for buffer (%X)\n", + obj_desc->common_field.bit_length, buffer_length)); + + return_ACPI_STATUS (AE_BUFFER_OVERFLOW); + } + + /* Compute the number of datums (access width data items) */ + + mask = ACPI_MASK_BITS_BELOW (obj_desc->common_field.start_field_bit_offset); + datum_count = ACPI_ROUND_UP_TO (obj_desc->common_field.bit_length, + obj_desc->common_field.access_bit_width); + field_datum_count = ACPI_ROUND_UP_TO (obj_desc->common_field.bit_length + + obj_desc->common_field.start_field_bit_offset, + obj_desc->common_field.access_bit_width); + + /* Get initial Datum from the input buffer */ + + ACPI_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)) { + return_ACPI_STATUS (status); + } + + /* Start new output datum by merging with previous input datum */ + + field_offset += obj_desc->common_field.access_byte_width; + merged_datum = raw_datum >> + (obj_desc->common_field.access_bit_width - obj_desc->common_field.start_field_bit_offset); + mask = ACPI_INTEGER_MAX; + + if (i == datum_count) { + break; + } + + /* Get the next input datum from the buffer */ + + buffer_offset += obj_desc->common_field.access_byte_width; + ACPI_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) % obj_desc->common_field.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); + + return_ACPI_STATUS (status); +} + + |