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linux/drivers/acpi/acpica/exfldio.c
Bob Moore 5df7e6cb42 ACPICA: Remove obsolete ACPI_INTEGER (acpi_integer) type 
This type was introduced as the code was migrated from ACPI 1.0
(with 32-bit AML integers) to ACPI 2.0 (with 64-bit integers). It
is now obsolete and this change removes it from the ACPICA code
base, replaced by u64.  The original typedef has been retained
for now for compatibility with existing device driver code.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-22 12:30:06 -05:00

960 lines
28 KiB
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/******************************************************************************
*
* Module Name: exfldio - Aml Field I/O
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2010, Intel Corp.
* 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 "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;
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 %X (%s)",
rgn_desc->common.type,
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);
}
}
/* Exit if Address/Length have been disallowed by the host OS */
if (rgn_desc->common.flags & AOPOBJ_INVALID) {
return_ACPI_STATUS(AE_AML_ILLEGAL_ADDRESS);
}
/*
* Exit now for SMBus or IPMI address space, it has a non-linear address space
* and the request cannot be directly validated
*/
if (rgn_desc->region.space_id == ACPI_ADR_SPACE_SMBUS ||
rgn_desc->region.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 (%d bytes) too large for region [%4.4s] (length %X)",
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 %X+%X+%X is beyond end of region [%4.4s] (length %X)",
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 %p\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_CAST_PTR(void,
(rgn_desc->
region.
address +
region_offset))));
/* Invoke the appropriate address_space/op_region handler */
status =
acpi_ev_address_space_dispatch(rgn_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(%X) 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(%X) 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.
*/
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.
*/
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,
(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 %X",
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 %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 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,
&current_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: %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 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 %X (bits) is too large for buffer (%X)",
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.
*
* 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 ((obj_desc->common_field.access_bit_width -
obj_desc->common_field.start_field_bit_offset) <
ACPI_INTEGER_BIT_SIZE) {
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;
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 i;
u32 required_length;
void *new_buffer;
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.
*/
ACPI_MEMCPY((char *)new_buffer, (char *)buffer, buffer_length);
buffer = new_buffer;
buffer_length = required_length;
}
/*
* Create the bitmasks used for bit insertion.
* Note: This if/else is used to bypass compiler differences with the
* shift operator
*/
if (obj_desc->common_field.access_bit_width == ACPI_INTEGER_BIT_SIZE) {
width_mask = ACPI_UINT64_MAX;
} else {
width_mask =
ACPI_MASK_BITS_ABOVE(obj_desc->common_field.
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,
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)) {
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 ((obj_desc->common_field.access_bit_width -
obj_desc->common_field.start_field_bit_offset) <
ACPI_INTEGER_BIT_SIZE) {
merged_datum =
raw_datum >> (obj_desc->common_field.
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;
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);
exit:
/* Free temporary buffer if we used one */
if (new_buffer) {
ACPI_FREE(new_buffer);
}
return_ACPI_STATUS(status);
}
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