[deliverable/linux.git] / drivers / acpi / executer / exfield.c

/******************************************************************************
 *
 * Module Name: exfield - ACPI AML (p-code) execution - field manipulation
 *
 *****************************************************************************/

/*
 * 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/acdispat.h>
#include <acpi/acinterp.h>


#define _COMPONENT          ACPI_EXECUTER
	 ACPI_MODULE_NAME    ("exfield")


/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_read_data_from_field
 *
 * PARAMETERS:  walk_state          - Current execution state
 *              obj_desc            - The named field
 *              ret_buffer_desc     - Where the return data object is stored
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Read from a named field.  Returns either an Integer or a
 *              Buffer, depending on the size of the field.
 *
 ******************************************************************************/

acpi_status
acpi_ex_read_data_from_field (
	struct acpi_walk_state          *walk_state,
	union acpi_operand_object       *obj_desc,
	union acpi_operand_object       **ret_buffer_desc)
{
	acpi_status                     status;
	union acpi_operand_object       *buffer_desc;
	acpi_size                       length;
	void                            *buffer;
	u8                              locked;


	ACPI_FUNCTION_TRACE_PTR ("ex_read_data_from_field", obj_desc);


	/* Parameter validation */

	if (!obj_desc) {
		return_ACPI_STATUS (AE_AML_NO_OPERAND);
	}
	if (!ret_buffer_desc) {
		return_ACPI_STATUS (AE_BAD_PARAMETER);
	}

	if (ACPI_GET_OBJECT_TYPE (obj_desc) == 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);
			}
		}
	}
	else if ((ACPI_GET_OBJECT_TYPE (obj_desc) == ACPI_TYPE_LOCAL_REGION_FIELD) &&
			 (obj_desc->field.region_obj->region.space_id == ACPI_ADR_SPACE_SMBUS)) {
		/*
		 * This is an SMBus read.  We must create a buffer to hold the data
		 * and directly access the region handler.
		 */
		buffer_desc = acpi_ut_create_buffer_object (ACPI_SMBUS_BUFFER_SIZE);
		if (!buffer_desc) {
			return_ACPI_STATUS (AE_NO_MEMORY);
		}

		/* Lock entire transaction if requested */

		locked = acpi_ex_acquire_global_lock (obj_desc->common_field.field_flags);

		/*
		 * Perform the read.
		 * Note: Smbus protocol value is passed in upper 16-bits of Function
		 */
		status = acpi_ex_access_region (obj_desc, 0,
				 ACPI_CAST_PTR (acpi_integer, buffer_desc->buffer.pointer),
				 ACPI_READ | (obj_desc->field.attribute << 16));
		acpi_ex_release_global_lock (locked);
		goto exit;
	}

	/*
	 * Allocate a buffer for the contents of the field.
	 *
	 * If the field is larger than the size of an acpi_integer, create
	 * a BUFFER to hold it.  Otherwise, use an INTEGER.  This allows
	 * the use of arithmetic operators on the returned value if the
	 * field size is equal or smaller than an Integer.
	 *
	 * Note: Field.length is in bits.
	 */
	length = (acpi_size) ACPI_ROUND_BITS_UP_TO_BYTES (obj_desc->field.bit_length);
	if (length > acpi_gbl_integer_byte_width) {
		/* Field is too large for an Integer, create a Buffer instead */

		buffer_desc = acpi_ut_create_buffer_object (length);
		if (!buffer_desc) {
			return_ACPI_STATUS (AE_NO_MEMORY);
		}
		buffer = buffer_desc->buffer.pointer;
	}
	else {
		/* Field will fit within an Integer (normal case) */

		buffer_desc = acpi_ut_create_internal_object (ACPI_TYPE_INTEGER);
		if (!buffer_desc) {
			return_ACPI_STATUS (AE_NO_MEMORY);
		}

		length = acpi_gbl_integer_byte_width;
		buffer_desc->integer.value = 0;
		buffer = &buffer_desc->integer.value;
	}

	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
		"field_read [TO]:  Obj %p, Type %X, Buf %p, byte_len %X\n",
		obj_desc, ACPI_GET_OBJECT_TYPE (obj_desc), buffer, (u32) length));
	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
		"field_read [FROM]: bit_len %X, bit_off %X, byte_off %X\n",
		obj_desc->common_field.bit_length,
		obj_desc->common_field.start_field_bit_offset,
		obj_desc->common_field.base_byte_offset));

	/* Lock entire transaction if requested */

	locked = acpi_ex_acquire_global_lock (obj_desc->common_field.field_flags);

	/* Read from the field */

	status = acpi_ex_extract_from_field (obj_desc, buffer, (u32) length);
	acpi_ex_release_global_lock (locked);


exit:
	if (ACPI_FAILURE (status)) {
		acpi_ut_remove_reference (buffer_desc);
	}
	else {
		*ret_buffer_desc = buffer_desc;
	}

	return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_write_data_to_field
 *
 * PARAMETERS:  source_desc         - Contains data to write
 *              obj_desc            - The named field
 *              result_desc         - Where the return value is returned, if any
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Write to a named field
 *
 ******************************************************************************/

acpi_status
acpi_ex_write_data_to_field (
	union acpi_operand_object       *source_desc,
	union acpi_operand_object       *obj_desc,
	union acpi_operand_object       **result_desc)
{
	acpi_status                     status;
	u32                             length;
	u32                             required_length;
	void                            *buffer;
	void                            *new_buffer;
	u8                              locked;
	union acpi_operand_object       *buffer_desc;


	ACPI_FUNCTION_TRACE_PTR ("ex_write_data_to_field", obj_desc);


	/* Parameter validation */

	if (!source_desc || !obj_desc) {
		return_ACPI_STATUS (AE_AML_NO_OPERAND);
	}

	if (ACPI_GET_OBJECT_TYPE (obj_desc) == 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);
			}
		}
	}
	else if ((ACPI_GET_OBJECT_TYPE (obj_desc) == ACPI_TYPE_LOCAL_REGION_FIELD) &&
			 (obj_desc->field.region_obj->region.space_id == ACPI_ADR_SPACE_SMBUS)) {
		/*
		 * This is an SMBus write.  We will bypass the entire field mechanism
		 * and handoff the buffer directly to the handler.
		 *
		 * Source must be a buffer of sufficient size (ACPI_SMBUS_BUFFER_SIZE).
		 */
		if (ACPI_GET_OBJECT_TYPE (source_desc) != ACPI_TYPE_BUFFER) {
			ACPI_REPORT_ERROR (("SMBus write requires Buffer, found type %s\n",
				acpi_ut_get_object_type_name (source_desc)));

			return_ACPI_STATUS (AE_AML_OPERAND_TYPE);
		}

		if (source_desc->buffer.length < ACPI_SMBUS_BUFFER_SIZE) {
			ACPI_REPORT_ERROR ((
				"SMBus write requires Buffer of length %X, found length %X\n",
				ACPI_SMBUS_BUFFER_SIZE, source_desc->buffer.length));

			return_ACPI_STATUS (AE_AML_BUFFER_LIMIT);
		}

		buffer_desc = acpi_ut_create_buffer_object (ACPI_SMBUS_BUFFER_SIZE);
		if (!buffer_desc) {
			return_ACPI_STATUS (AE_NO_MEMORY);
		}

		buffer = buffer_desc->buffer.pointer;
		ACPI_MEMCPY (buffer, source_desc->buffer.pointer,
			ACPI_SMBUS_BUFFER_SIZE);

		/* Lock entire transaction if requested */

		locked = acpi_ex_acquire_global_lock (obj_desc->common_field.field_flags);

		/*
		 * Perform the write (returns status and perhaps data in the
		 * same buffer)
		 * Note: SMBus protocol type is passed in upper 16-bits of Function.
		 */
		status = acpi_ex_access_region (obj_desc, 0,
				  (acpi_integer *) buffer,
				  ACPI_WRITE | (obj_desc->field.attribute << 16));
		acpi_ex_release_global_lock (locked);

		*result_desc = buffer_desc;
		return_ACPI_STATUS (status);
	}

	/* Get a pointer to the data to be written */

	switch (ACPI_GET_OBJECT_TYPE (source_desc)) {
	case ACPI_TYPE_INTEGER:
		buffer = &source_desc->integer.value;
		length = sizeof (source_desc->integer.value);
		break;

	case ACPI_TYPE_BUFFER:
		buffer = source_desc->buffer.pointer;
		length = source_desc->buffer.length;
		break;

	case ACPI_TYPE_STRING:
		buffer = source_desc->string.pointer;
		length = source_desc->string.length;
		break;

	default:
		return_ACPI_STATUS (AE_AML_OPERAND_TYPE);
	}

	/*
	 * 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.
	 */
	new_buffer = NULL;
	required_length = ACPI_ROUND_BITS_UP_TO_BYTES (
			   obj_desc->common_field.bit_length);

	if (length < required_length) {
		/* We need to create a new buffer */

		new_buffer = ACPI_MEM_CALLOCATE (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, length);
		buffer = new_buffer;
		length = required_length;
	}

	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
		"field_write [FROM]: Obj %p (%s:%X), Buf %p, byte_len %X\n",
		source_desc, acpi_ut_get_type_name (ACPI_GET_OBJECT_TYPE (source_desc)),
		ACPI_GET_OBJECT_TYPE (source_desc), buffer, length));

	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
		"field_write [TO]:  Obj %p (%s:%X), bit_len %X, bit_off %X, byte_off %X\n",
		obj_desc, acpi_ut_get_type_name (ACPI_GET_OBJECT_TYPE (obj_desc)),
		ACPI_GET_OBJECT_TYPE (obj_desc),
		obj_desc->common_field.bit_length,
		obj_desc->common_field.start_field_bit_offset,
		obj_desc->common_field.base_byte_offset));

	/* Lock entire transaction if requested */

	locked = acpi_ex_acquire_global_lock (obj_desc->common_field.field_flags);

	/* Write to the field */

	status = acpi_ex_insert_into_field (obj_desc, buffer, length);
	acpi_ex_release_global_lock (locked);

	/* Free temporary buffer if we used one */

	if (new_buffer) {
		ACPI_MEM_FREE (new_buffer);
	}

	return_ACPI_STATUS (status);
}
Commit	Line	Data
1da177e4 LT	1	/******************************************************************************
	2	*
	3	* Module Name: exfield - ACPI AML (p-code) execution - field manipulation
	4	*
	5	*****************************************************************************/
	6
	7	/*
	8	* Copyright (C) 2000 - 2005, R. Byron Moore
	9	* All rights reserved.
	10	*
	11	* Redistribution and use in source and binary forms, with or without
	12	* modification, are permitted provided that the following conditions
	13	* are met:
	14	* 1. Redistributions of source code must retain the above copyright
	15	* notice, this list of conditions, and the following disclaimer,
	16	* without modification.
	17	* 2. Redistributions in binary form must reproduce at minimum a disclaimer
	18	* substantially similar to the "NO WARRANTY" disclaimer below
	19	* ("Disclaimer") and any redistribution must be conditioned upon
	20	* including a substantially similar Disclaimer requirement for further
	21	* binary redistribution.
	22	* 3. Neither the names of the above-listed copyright holders nor the names
	23	* of any contributors may be used to endorse or promote products derived
	24	* from this software without specific prior written permission.
	25	*
	26	* Alternatively, this software may be distributed under the terms of the
	27	* GNU General Public License ("GPL") version 2 as published by the Free
	28	* Software Foundation.
	29	*
	30	* NO WARRANTY
	31	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	32	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	33	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
	34	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	35	* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	36	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	37	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	38	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	39	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
	40	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	41	* POSSIBILITY OF SUCH DAMAGES.
	42	*/
	43
	44
	45	#include <acpi/acpi.h>
	46	#include <acpi/acdispat.h>
	47	#include <acpi/acinterp.h>
	48
	49
	50	#define _COMPONENT ACPI_EXECUTER
	51	ACPI_MODULE_NAME ("exfield")
	52
	53
	54	/*******************************************************************************
	55	*
	56	* FUNCTION: acpi_ex_read_data_from_field
	57	*
	58	* PARAMETERS: walk_state - Current execution state
	59	* obj_desc - The named field
	60	* ret_buffer_desc - Where the return data object is stored
	61	*
	62	* RETURN: Status
	63	*
	64	* DESCRIPTION: Read from a named field. Returns either an Integer or a
65	* Buffer, depending on the size of the field.
66	*
67	******************************************************************************/
68
69	acpi_status
70	acpi_ex_read_data_from_field (
71	struct acpi_walk_state *walk_state,
72	union acpi_operand_object *obj_desc,
73	union acpi_operand_object **ret_buffer_desc)
74	{
75	acpi_status status;
76	union acpi_operand_object *buffer_desc;
77	acpi_size length;
78	void *buffer;
79	u8 locked;
80
81
82	ACPI_FUNCTION_TRACE_PTR ("ex_read_data_from_field", obj_desc);
83
84
85	/* Parameter validation */
86
87	if (!obj_desc) {
88	return_ACPI_STATUS (AE_AML_NO_OPERAND);
89	}
88ac00f5 RM	90	if (!ret_buffer_desc) {
	91	return_ACPI_STATUS (AE_BAD_PARAMETER);
	92	}
1da177e4 LT	93
	94	if (ACPI_GET_OBJECT_TYPE (obj_desc) == ACPI_TYPE_BUFFER_FIELD) {
	95	/*
	96	* If the buffer_field arguments have not been previously evaluated,
	97	* evaluate them now and save the results.
	98	*/
	99	if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
	100	status = acpi_ds_get_buffer_field_arguments (obj_desc);
	101	if (ACPI_FAILURE (status)) {
	102	return_ACPI_STATUS (status);
	103	}
	104	}
	105	}
	106	else if ((ACPI_GET_OBJECT_TYPE (obj_desc) == ACPI_TYPE_LOCAL_REGION_FIELD) &&
	107	(obj_desc->field.region_obj->region.space_id == ACPI_ADR_SPACE_SMBUS)) {
	108	/*
	109	* This is an SMBus read. We must create a buffer to hold the data
	110	* and directly access the region handler.
	111	*/
	112	buffer_desc = acpi_ut_create_buffer_object (ACPI_SMBUS_BUFFER_SIZE);
	113	if (!buffer_desc) {
	114	return_ACPI_STATUS (AE_NO_MEMORY);
	115	}
	116
	117	/* Lock entire transaction if requested */
	118
	119	locked = acpi_ex_acquire_global_lock (obj_desc->common_field.field_flags);
	120
	121	/*
	122	* Perform the read.
	123	* Note: Smbus protocol value is passed in upper 16-bits of Function
	124	*/
	125	status = acpi_ex_access_region (obj_desc, 0,
44f6c012 RM	126	ACPI_CAST_PTR (acpi_integer, buffer_desc->buffer.pointer),
44f6c012 RM	127	ACPI_READ \| (obj_desc->field.attribute << 16));
1da177e4 LT	128	acpi_ex_release_global_lock (locked);
	129	goto exit;
	130	}
	131
	132	/*
	133	* Allocate a buffer for the contents of the field.
	134	*
	135	* If the field is larger than the size of an acpi_integer, create
	136	* a BUFFER to hold it. Otherwise, use an INTEGER. This allows
	137	* the use of arithmetic operators on the returned value if the
	138	* field size is equal or smaller than an Integer.
	139	*
	140	* Note: Field.length is in bits.
	141	*/
	142	length = (acpi_size) ACPI_ROUND_BITS_UP_TO_BYTES (obj_desc->field.bit_length);
	143	if (length > acpi_gbl_integer_byte_width) {
	144	/* Field is too large for an Integer, create a Buffer instead */
	145
	146	buffer_desc = acpi_ut_create_buffer_object (length);
	147	if (!buffer_desc) {
	148	return_ACPI_STATUS (AE_NO_MEMORY);
	149	}
	150	buffer = buffer_desc->buffer.pointer;
	151	}
	152	else {
	153	/* Field will fit within an Integer (normal case) */
	154
	155	buffer_desc = acpi_ut_create_internal_object (ACPI_TYPE_INTEGER);
	156	if (!buffer_desc) {
	157	return_ACPI_STATUS (AE_NO_MEMORY);
	158	}
	159
	160	length = acpi_gbl_integer_byte_width;
	161	buffer_desc->integer.value = 0;
	162	buffer = &buffer_desc->integer.value;
	163	}
	164
	165	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
	166	"field_read [TO]: Obj %p, Type %X, Buf %p, byte_len %X\n",
	167	obj_desc, ACPI_GET_OBJECT_TYPE (obj_desc), buffer, (u32) length));
	168	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
	169	"field_read [FROM]: bit_len %X, bit_off %X, byte_off %X\n",
	170	obj_desc->common_field.bit_length,
	171	obj_desc->common_field.start_field_bit_offset,
	172	obj_desc->common_field.base_byte_offset));
	173
	174	/* Lock entire transaction if requested */
	175
	176	locked = acpi_ex_acquire_global_lock (obj_desc->common_field.field_flags);
	177
	178	/* Read from the field */
	179
	180	status = acpi_ex_extract_from_field (obj_desc, buffer, (u32) length);
	181	acpi_ex_release_global_lock (locked);
	182
	183
	184	exit:
	185	if (ACPI_FAILURE (status)) {
	186	acpi_ut_remove_reference (buffer_desc);
	187	}
88ac00f5	188	else {
1da177e4 LT	189	*ret_buffer_desc = buffer_desc;
	190	}
	191
	192	return_ACPI_STATUS (status);
	193	}
	194
	195
	196	/*******************************************************************************
	197	*
	198	* FUNCTION: acpi_ex_write_data_to_field
	199	*
	200	* PARAMETERS: source_desc - Contains data to write
	201	* obj_desc - The named field
44f6c012	202	* result_desc - Where the return value is returned, if any
1da177e4 LT	203	*
	204	* RETURN: Status
	205	*
	206	* DESCRIPTION: Write to a named field
	207	*
	208	******************************************************************************/
	209
	210	acpi_status
	211	acpi_ex_write_data_to_field (
	212	union acpi_operand_object *source_desc,
	213	union acpi_operand_object *obj_desc,
	214	union acpi_operand_object **result_desc)
	215	{
	216	acpi_status status;
	217	u32 length;
	218	u32 required_length;
	219	void *buffer;
	220	void *new_buffer;
	221	u8 locked;
	222	union acpi_operand_object *buffer_desc;
	223
	224
	225	ACPI_FUNCTION_TRACE_PTR ("ex_write_data_to_field", obj_desc);
	226
	227
	228	/* Parameter validation */
	229
	230	if (!source_desc \|\| !obj_desc) {
	231	return_ACPI_STATUS (AE_AML_NO_OPERAND);
	232	}
	233
	234	if (ACPI_GET_OBJECT_TYPE (obj_desc) == ACPI_TYPE_BUFFER_FIELD) {
	235	/*
	236	* If the buffer_field arguments have not been previously evaluated,
	237	* evaluate them now and save the results.
	238	*/
	239	if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
	240	status = acpi_ds_get_buffer_field_arguments (obj_desc);
	241	if (ACPI_FAILURE (status)) {
	242	return_ACPI_STATUS (status);
	243	}
	244	}
	245	}
	246	else if ((ACPI_GET_OBJECT_TYPE (obj_desc) == ACPI_TYPE_LOCAL_REGION_FIELD) &&
	247	(obj_desc->field.region_obj->region.space_id == ACPI_ADR_SPACE_SMBUS)) {
	248	/*
	249	* This is an SMBus write. We will bypass the entire field mechanism
	250	* and handoff the buffer directly to the handler.
	251	*
	252	* Source must be a buffer of sufficient size (ACPI_SMBUS_BUFFER_SIZE).
	253	*/
	254	if (ACPI_GET_OBJECT_TYPE (source_desc) != ACPI_TYPE_BUFFER) {
	255	ACPI_REPORT_ERROR (("SMBus write requires Buffer, found type %s\n",
	256	acpi_ut_get_object_type_name (source_desc)));
44f6c012	257
1da177e4 LT	258	return_ACPI_STATUS (AE_AML_OPERAND_TYPE);
	259	}
	260
	261	if (source_desc->buffer.length < ACPI_SMBUS_BUFFER_SIZE) {
44f6c012 RM	262	ACPI_REPORT_ERROR ((
44f6c012 RM	263	"SMBus write requires Buffer of length %X, found length %X\n",
1da177e4	264	ACPI_SMBUS_BUFFER_SIZE, source_desc->buffer.length));
44f6c012	265
1da177e4 LT	266	return_ACPI_STATUS (AE_AML_BUFFER_LIMIT);
	267	}
	268
	269	buffer_desc = acpi_ut_create_buffer_object (ACPI_SMBUS_BUFFER_SIZE);
	270	if (!buffer_desc) {
	271	return_ACPI_STATUS (AE_NO_MEMORY);
	272	}
	273
	274	buffer = buffer_desc->buffer.pointer;
44f6c012 RM	275	ACPI_MEMCPY (buffer, source_desc->buffer.pointer,
44f6c012 RM	276	ACPI_SMBUS_BUFFER_SIZE);
1da177e4 LT	277
	278	/* Lock entire transaction if requested */
	279
	280	locked = acpi_ex_acquire_global_lock (obj_desc->common_field.field_flags);
	281
	282	/*
44f6c012 RM	283	* Perform the write (returns status and perhaps data in the
44f6c012 RM	284	* same buffer)
1da177e4 LT	285	* Note: SMBus protocol type is passed in upper 16-bits of Function.
	286	*/
	287	status = acpi_ex_access_region (obj_desc, 0,
	288	(acpi_integer *) buffer,
	289	ACPI_WRITE \| (obj_desc->field.attribute << 16));
	290	acpi_ex_release_global_lock (locked);
	291
	292	*result_desc = buffer_desc;
	293	return_ACPI_STATUS (status);
	294	}
	295
44f6c012 RM	296	/* Get a pointer to the data to be written */
44f6c012 RM	297
1da177e4 LT	298	switch (ACPI_GET_OBJECT_TYPE (source_desc)) {
	299	case ACPI_TYPE_INTEGER:
	300	buffer = &source_desc->integer.value;
	301	length = sizeof (source_desc->integer.value);
	302	break;
	303
	304	case ACPI_TYPE_BUFFER:
	305	buffer = source_desc->buffer.pointer;
	306	length = source_desc->buffer.length;
	307	break;
	308
	309	case ACPI_TYPE_STRING:
	310	buffer = source_desc->string.pointer;
	311	length = source_desc->string.length;
	312	break;
	313
	314	default:
	315	return_ACPI_STATUS (AE_AML_OPERAND_TYPE);
	316	}
	317
	318	/*
	319	* We must have a buffer that is at least as long as the field
	320	* we are writing to. This is because individual fields are
	321	* indivisible and partial writes are not supported -- as per
	322	* the ACPI specification.
	323	*/
	324	new_buffer = NULL;
44f6c012 RM	325	required_length = ACPI_ROUND_BITS_UP_TO_BYTES (
44f6c012 RM	326	obj_desc->common_field.bit_length);
1da177e4 LT	327
	328	if (length < required_length) {
	329	/* We need to create a new buffer */
	330
	331	new_buffer = ACPI_MEM_CALLOCATE (required_length);
	332	if (!new_buffer) {
	333	return_ACPI_STATUS (AE_NO_MEMORY);
	334	}
	335
	336	/*
	337	* Copy the original data to the new buffer, starting
	338	* at Byte zero. All unused (upper) bytes of the
	339	* buffer will be 0.
	340	*/
	341	ACPI_MEMCPY ((char ) new_buffer, (char ) buffer, length);
	342	buffer = new_buffer;
	343	length = required_length;
	344	}
	345
	346	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
	347	"field_write [FROM]: Obj %p (%s:%X), Buf %p, byte_len %X\n",
	348	source_desc, acpi_ut_get_type_name (ACPI_GET_OBJECT_TYPE (source_desc)),
	349	ACPI_GET_OBJECT_TYPE (source_desc), buffer, length));
44f6c012	350
1da177e4 LT	351	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
	352	"field_write [TO]: Obj %p (%s:%X), bit_len %X, bit_off %X, byte_off %X\n",
	353	obj_desc, acpi_ut_get_type_name (ACPI_GET_OBJECT_TYPE (obj_desc)),
	354	ACPI_GET_OBJECT_TYPE (obj_desc),
	355	obj_desc->common_field.bit_length,
	356	obj_desc->common_field.start_field_bit_offset,
	357	obj_desc->common_field.base_byte_offset));
	358
	359	/* Lock entire transaction if requested */
	360
	361	locked = acpi_ex_acquire_global_lock (obj_desc->common_field.field_flags);
	362
	363	/* Write to the field */
	364
	365	status = acpi_ex_insert_into_field (obj_desc, buffer, length);
	366	acpi_ex_release_global_lock (locked);
	367
	368	/* Free temporary buffer if we used one */
	369
	370	if (new_buffer) {
	371	ACPI_MEM_FREE (new_buffer);
	372	}
	373
	374	return_ACPI_STATUS (status);
	375	}
	376
	377