ACPI_STATUS
AcpiExInsertIntoField (
ACPI_OPERAND_OBJECT *ObjDesc,
void *Buffer,
UINT32 BufferLength)
{
void *NewBuffer;
ACPI_STATUS Status;
UINT64 Mask;
UINT64 WidthMask;
UINT64 MergedDatum;
UINT64 RawDatum = 0;
UINT32 FieldOffset = 0;
UINT32 BufferOffset = 0;
UINT32 BufferTailBits;
UINT32 DatumCount;
UINT32 FieldDatumCount;
UINT32 AccessBitWidth;
UINT32 RequiredLength;
UINT32 i;
ACPI_FUNCTION_TRACE (ExInsertIntoField);
/* Validate input buffer */
NewBuffer = NULL;
RequiredLength = ACPI_ROUND_BITS_UP_TO_BYTES (
ObjDesc->CommonField.BitLength);
/*
* 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 (BufferLength < RequiredLength)
{
/* We need to create a new buffer */
NewBuffer = ACPI_ALLOCATE_ZEROED (RequiredLength);
if (!NewBuffer)
{
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 *) NewBuffer, (char *) Buffer, BufferLength);
Buffer = NewBuffer;
BufferLength = RequiredLength;
}
/* TBD: Move to common setup code */
/* Algo is limited to sizeof(UINT64), so cut the AccessByteWidth */
if (ObjDesc->CommonField.AccessByteWidth > sizeof (UINT64))
{
ObjDesc->CommonField.AccessByteWidth = sizeof (UINT64);
}
AccessBitWidth = ACPI_MUL_8 (ObjDesc->CommonField.AccessByteWidth);
/*
* Create the bitmasks used for bit insertion.
* Note: This if/else is used to bypass compiler differences with the
* shift operator
*/
if (AccessBitWidth == ACPI_INTEGER_BIT_SIZE)
{
WidthMask = ACPI_UINT64_MAX;
}
else
{
WidthMask = ACPI_MASK_BITS_ABOVE (AccessBitWidth);
}
Mask = WidthMask &
ACPI_MASK_BITS_BELOW (ObjDesc->CommonField.StartFieldBitOffset);
/* Compute the number of datums (access width data items) */
DatumCount = ACPI_ROUND_UP_TO (ObjDesc->CommonField.BitLength,
AccessBitWidth);
FieldDatumCount = ACPI_ROUND_UP_TO (ObjDesc->CommonField.BitLength +
ObjDesc->CommonField.StartFieldBitOffset,
AccessBitWidth);
/* Get initial Datum from the input buffer */
memcpy (&RawDatum, Buffer,
ACPI_MIN(ObjDesc->CommonField.AccessByteWidth,
BufferLength - BufferOffset));
MergedDatum = RawDatum << ObjDesc->CommonField.StartFieldBitOffset;
/* Write the entire field */
for (i = 1; i < FieldDatumCount; i++)
{
/* Write merged datum to the target field */
MergedDatum &= Mask;
Status = AcpiExWriteWithUpdateRule (ObjDesc, Mask,
MergedDatum, FieldOffset);
if (ACPI_FAILURE (Status))
{
goto Exit;
}
FieldOffset += ObjDesc->CommonField.AccessByteWidth;
/*
* 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 ((AccessBitWidth - ObjDesc->CommonField.StartFieldBitOffset) <
ACPI_INTEGER_BIT_SIZE)
{
MergedDatum = RawDatum >>
(AccessBitWidth - ObjDesc->CommonField.StartFieldBitOffset);
}
else
{
ACPI_STATUS
AcpiHwWrite (
UINT32 Value,
ACPI_GENERIC_ADDRESS *Reg)
{
UINT64 Address;
UINT8 AccessWidth;
UINT32 BitWidth;
UINT8 BitOffset;
UINT64 Value64;
UINT32 NewValue32, OldValue32;
UINT8 Index;
ACPI_STATUS Status;
ACPI_FUNCTION_NAME (HwWrite);
/* Validate contents of the GAS register */
Status = AcpiHwValidateRegister (Reg, 32, &Address);
if (ACPI_FAILURE (Status))
{
return (Status);
}
/* Convert AccessWidth into number of bits based */
AccessWidth = Reg->AccessWidth ? Reg->AccessWidth : 1;
AccessWidth = 1 << (AccessWidth + 2);
BitWidth = ACPI_ROUND_UP (Reg->BitOffset + Reg->BitWidth, AccessWidth);
BitOffset = Reg->BitOffset;
/*
* Two address spaces supported: Memory or IO. PCI_Config is
* not supported here because the GAS structure is insufficient
*/
Index = 0;
while (BitWidth)
{
NewValue32 = ACPI_GET_BITS (&Value, (Index * AccessWidth),
((1 << AccessWidth) - 1));
if (BitOffset > AccessWidth)
{
BitOffset -= AccessWidth;
}
else
{
if (BitOffset)
{
NewValue32 &= ACPI_MASK_BITS_BELOW (BitOffset);
}
if (BitWidth < AccessWidth)
{
NewValue32 &= ACPI_MASK_BITS_ABOVE (BitWidth);
}
if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
{
if (BitOffset || BitWidth < AccessWidth)
{
/*
* Read old values in order not to modify the bits that
* are beyond the register BitWidth/BitOffset setting.
*/
Status = AcpiOsReadMemory ((ACPI_PHYSICAL_ADDRESS)
Address + Index * ACPI_DIV_8 (AccessWidth),
&Value64, AccessWidth);
OldValue32 = (UINT32) Value64;
if (BitOffset)
{
OldValue32 &= ACPI_MASK_BITS_ABOVE (BitOffset + 1);
BitOffset = 0;
}
if (BitWidth < AccessWidth)
{
OldValue32 &= ACPI_MASK_BITS_BELOW (BitWidth - 1);
}
NewValue32 |= OldValue32;
}
Value64 = (UINT64) NewValue32;
Status = AcpiOsWriteMemory ((ACPI_PHYSICAL_ADDRESS)
Address + Index * ACPI_DIV_8 (AccessWidth),
Value64, AccessWidth);
}
else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
{
if (BitOffset || BitWidth < AccessWidth)
{
/*
* Read old values in order not to modify the bits that
* are beyond the register BitWidth/BitOffset setting.
*/
Status = AcpiHwReadPort ((ACPI_IO_ADDRESS)
Address + Index * ACPI_DIV_8 (AccessWidth),
&OldValue32, AccessWidth);
if (BitOffset)
{
OldValue32 &= ACPI_MASK_BITS_ABOVE (BitOffset + 1);
BitOffset = 0;
}
if (BitWidth < AccessWidth)
{
OldValue32 &= ACPI_MASK_BITS_BELOW (BitWidth - 1);
}
NewValue32 |= OldValue32;
}
Status = AcpiHwWritePort ((ACPI_IO_ADDRESS)
Address + Index * ACPI_DIV_8 (AccessWidth),
NewValue32, AccessWidth);
}
}
BitWidth -= BitWidth > AccessWidth ? AccessWidth : BitWidth;
Index++;
}
ACPI_DEBUG_PRINT ((ACPI_DB_IO,
"Wrote: %8.8X width %2d to %8.8X%8.8X (%s)\n",
Value, AccessWidth, ACPI_FORMAT_UINT64 (Address),
AcpiUtGetRegionName (Reg->SpaceId)));
return (Status);
}
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.
*/
ACPI_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.
* Note: This if/else is used to bypass compiler differences with the
* shift operator
*/
if (access_bit_width == ACPI_INTEGER_BIT_SIZE) {
width_mask = ACPI_UINT64_MAX;
} else {
width_mask = ACPI_MASK_BITS_ABOVE(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 */
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 ((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 {
ACPI_STATUS
AcpiHwRead (
UINT32 *Value,
ACPI_GENERIC_ADDRESS *Reg)
{
UINT64 Address;
UINT8 AccessWidth;
UINT32 BitWidth;
UINT8 BitOffset;
UINT64 Value64;
UINT32 Value32;
UINT8 Index;
ACPI_STATUS Status;
ACPI_FUNCTION_NAME (HwRead);
/* Validate contents of the GAS register */
Status = AcpiHwValidateRegister (Reg, 32, &Address);
if (ACPI_FAILURE (Status))
{
return (Status);
}
/*
* Initialize entire 32-bit return value to zero, convert AccessWidth
* into number of bits based
*/
*Value = 0;
AccessWidth = Reg->AccessWidth ? Reg->AccessWidth : 1;
AccessWidth = 1 << (AccessWidth + 2);
BitWidth = ACPI_ROUND_UP (Reg->BitOffset + Reg->BitWidth, AccessWidth);
BitOffset = Reg->BitOffset;
/*
* Two address spaces supported: Memory or IO. PCI_Config is
* not supported here because the GAS structure is insufficient
*/
Index = 0;
while (BitWidth)
{
if (BitOffset > AccessWidth)
{
Value32 = 0;
BitOffset -= AccessWidth;
}
else
{
if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
{
Status = AcpiOsReadMemory ((ACPI_PHYSICAL_ADDRESS)
Address + Index * ACPI_DIV_8 (AccessWidth),
&Value64, AccessWidth);
Value32 = (UINT32) Value64;
}
else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
{
Status = AcpiHwReadPort ((ACPI_IO_ADDRESS)
Address + Index * ACPI_DIV_8 (AccessWidth),
&Value32, AccessWidth);
}
if (BitOffset)
{
Value32 &= ACPI_MASK_BITS_BELOW (BitOffset);
BitOffset = 0;
}
if (BitWidth < AccessWidth)
{
Value32 &= ACPI_MASK_BITS_ABOVE (BitWidth);
}
}
ACPI_SET_BITS (Value, Index * AccessWidth,
((1 << AccessWidth) - 1), Value32);
BitWidth -= BitWidth > AccessWidth ? AccessWidth : BitWidth;
Index++;
}
ACPI_DEBUG_PRINT ((ACPI_DB_IO,
"Read: %8.8X width %2d from %8.8X%8.8X (%s)\n",
*Value, AccessWidth, ACPI_FORMAT_UINT64 (Address),
AcpiUtGetRegionName (Reg->SpaceId)));
return (Status);
}
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);
}
acpi_status acpi_hw_write(u32 value, struct acpi_generic_address *reg)
{
u64 address;
u8 access_width;
u32 bit_width;
u8 bit_offset;
u64 value64;
u32 new_value32, old_value32;
u8 index;
acpi_status status;
ACPI_FUNCTION_NAME(hw_write);
/* Validate contents of the GAS register */
status = acpi_hw_validate_register(reg, 32, &address);
if (ACPI_FAILURE(status)) {
return (status);
}
/* Convert access_width into number of bits based */
access_width = acpi_hw_get_access_bit_width(reg, 32);
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 32-bits by acpi_hw_validate_register().
*/
new_value32 = ACPI_GET_BITS(&value, index * access_width,
ACPI_MASK_BITS_ABOVE_32
(access_width));
if (bit_offset >= access_width) {
bit_offset -= access_width;
} else {
/*
* Use offset style bit masks because access_width is ensured
* to be less than 32-bits by acpi_hw_validate_register() and
* bit_offset/bit_width is less than access_width here.
*/
if (bit_offset) {
new_value32 &= ACPI_MASK_BITS_BELOW(bit_offset);
}
if (bit_width < access_width) {
new_value32 &= ACPI_MASK_BITS_ABOVE(bit_width);
}
if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
if (bit_offset || bit_width < access_width) {
/*
* Read old values in order not to modify the bits that
* are beyond the register bit_width/bit_offset setting.
*/
status =
acpi_os_read_memory((acpi_physical_address)
address +
index *
ACPI_DIV_8
(access_width),
&value64,
access_width);
old_value32 = (u32)value64;
/*
* Use offset style bit masks because access_width is
* ensured to be less than 32-bits by
* acpi_hw_validate_register() and bit_offset/bit_width is
* less than access_width here.
*/
if (bit_offset) {
old_value32 &=
ACPI_MASK_BITS_ABOVE
(bit_offset);
bit_offset = 0;
}
if (bit_width < access_width) {
old_value32 &=
ACPI_MASK_BITS_BELOW
(bit_width);
}
new_value32 |= old_value32;
}
value64 = (u64)new_value32;
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 */
if (bit_offset || bit_width < access_width) {
/*
* Read old values in order not to modify the bits that
* are beyond the register bit_width/bit_offset setting.
*/
status =
acpi_hw_read_port((acpi_io_address)
address +
index *
ACPI_DIV_8
(access_width),
&old_value32,
access_width);
/*
* Use offset style bit masks because access_width is
* ensured to be less than 32-bits by
* acpi_hw_validate_register() and bit_offset/bit_width is
* less than access_width here.
*/
if (bit_offset) {
old_value32 &=
ACPI_MASK_BITS_ABOVE
(bit_offset);
bit_offset = 0;
}
if (bit_width < access_width) {
old_value32 &=
ACPI_MASK_BITS_BELOW
(bit_width);
}
new_value32 |= old_value32;
}
status = acpi_hw_write_port((acpi_io_address)
address +
index *
ACPI_DIV_8
(access_width),
new_value32,
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 width %2d to %8.8X%8.8X (%s)\n",
value, access_width, ACPI_FORMAT_UINT64(address),
acpi_ut_get_region_name(reg->space_id)));
return (status);
}
acpi_status acpi_hw_read(u32 *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, 32, &address);
if (ACPI_FAILURE(status)) {
return (status);
}
/*
* Initialize entire 32-bit return value to zero, convert access_width
* into number of bits based
*/
*value = 0;
access_width = acpi_hw_get_access_bit_width(reg, 32);
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) {
value32 = 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);
value32 = (u32)value64;
} 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);
}
/*
* Use offset style bit masks because:
* bit_offset < access_width/bit_width < access_width, and
* access_width is ensured to be less than 32-bits by
* acpi_hw_validate_register().
*/
if (bit_offset) {
value32 &= ACPI_MASK_BITS_BELOW(bit_offset);
bit_offset = 0;
}
if (bit_width < access_width) {
value32 &= ACPI_MASK_BITS_ABOVE(bit_width);
}
}
/*
* Use offset style bit writes because "Index * AccessWidth" is
* ensured to be less than 32-bits by acpi_hw_validate_register().
*/
ACPI_SET_BITS(value, index * access_width,
ACPI_MASK_BITS_ABOVE_32(access_width), value32);
bit_width -=
bit_width > access_width ? access_width : bit_width;
index++;
}
ACPI_DEBUG_PRINT((ACPI_DB_IO,
"Read: %8.8X width %2d from %8.8X%8.8X (%s)\n",
*value, access_width, ACPI_FORMAT_UINT64(address),
acpi_ut_get_region_name(reg->space_id)));
return (status);
}
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 width_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_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);
}
/*
* 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_INTEGER_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)) {
return_ACPI_STATUS(status);
}
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 {
