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v3.5.6
   1/******************************************************************************
   2 *
   3 * Module Name: exfldio - Aml Field I/O
   4 *
   5 *****************************************************************************/
   6
   7/*
   8 * Copyright (C) 2000 - 2012, Intel Corp.
   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#include <acpi/acpi.h>
  45#include "accommon.h"
  46#include "acinterp.h"
  47#include "amlcode.h"
  48#include "acevents.h"
  49#include "acdispat.h"
  50
  51#define _COMPONENT          ACPI_EXECUTER
  52ACPI_MODULE_NAME("exfldio")
  53
  54/* Local prototypes */
  55static acpi_status
  56acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
  57		       u32 field_datum_byte_offset,
  58		       u64 *value, u32 read_write);
  59
  60static u8
  61acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value);
  62
  63static acpi_status
  64acpi_ex_setup_region(union acpi_operand_object *obj_desc,
  65		     u32 field_datum_byte_offset);
  66
  67/*******************************************************************************
  68 *
  69 * FUNCTION:    acpi_ex_setup_region
  70 *
  71 * PARAMETERS:  obj_desc                - Field to be read or written
  72 *              field_datum_byte_offset - Byte offset of this datum within the
  73 *                                        parent field
  74 *
  75 * RETURN:      Status
  76 *
  77 * DESCRIPTION: Common processing for acpi_ex_extract_from_field and
  78 *              acpi_ex_insert_into_field. Initialize the Region if necessary and
  79 *              validate the request.
  80 *
  81 ******************************************************************************/
  82
  83static acpi_status
  84acpi_ex_setup_region(union acpi_operand_object *obj_desc,
  85		     u32 field_datum_byte_offset)
  86{
  87	acpi_status status = AE_OK;
  88	union acpi_operand_object *rgn_desc;
  89	u8 space_id;
  90
  91	ACPI_FUNCTION_TRACE_U32(ex_setup_region, field_datum_byte_offset);
  92
  93	rgn_desc = obj_desc->common_field.region_obj;
  94
  95	/* We must have a valid region */
  96
  97	if (rgn_desc->common.type != ACPI_TYPE_REGION) {
  98		ACPI_ERROR((AE_INFO, "Needed Region, found type 0x%X (%s)",
  99			    rgn_desc->common.type,
 100			    acpi_ut_get_object_type_name(rgn_desc)));
 101
 102		return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
 103	}
 104
 105	space_id = rgn_desc->region.space_id;
 106
 107	/* Validate the Space ID */
 108
 109	if (!acpi_is_valid_space_id(space_id)) {
 110		ACPI_ERROR((AE_INFO,
 111			    "Invalid/unknown Address Space ID: 0x%2.2X",
 112			    space_id));
 113		return_ACPI_STATUS(AE_AML_INVALID_SPACE_ID);
 114	}
 115
 116	/*
 117	 * If the Region Address and Length have not been previously evaluated,
 118	 * evaluate them now and save the results.
 119	 */
 120	if (!(rgn_desc->common.flags & AOPOBJ_DATA_VALID)) {
 121		status = acpi_ds_get_region_arguments(rgn_desc);
 122		if (ACPI_FAILURE(status)) {
 123			return_ACPI_STATUS(status);
 124		}
 125	}
 126
 127	/* Exit if Address/Length have been disallowed by the host OS */
 128
 129	if (rgn_desc->common.flags & AOPOBJ_INVALID) {
 130		return_ACPI_STATUS(AE_AML_ILLEGAL_ADDRESS);
 131	}
 132
 133	/*
 134	 * Exit now for SMBus, GSBus or IPMI address space, it has a non-linear
 135	 * address space and the request cannot be directly validated
 136	 */
 137	if (space_id == ACPI_ADR_SPACE_SMBUS ||
 138	    space_id == ACPI_ADR_SPACE_GSBUS ||
 139	    space_id == ACPI_ADR_SPACE_IPMI) {
 140
 141		/* SMBus or IPMI has a non-linear address space */
 142
 143		return_ACPI_STATUS(AE_OK);
 144	}
 145#ifdef ACPI_UNDER_DEVELOPMENT
 146	/*
 147	 * If the Field access is any_acc, we can now compute the optimal
 148	 * access (because we know know the length of the parent region)
 149	 */
 150	if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
 151		if (ACPI_FAILURE(status)) {
 152			return_ACPI_STATUS(status);
 153		}
 154	}
 155#endif
 156
 157	/*
 158	 * Validate the request.  The entire request from the byte offset for a
 159	 * length of one field datum (access width) must fit within the region.
 160	 * (Region length is specified in bytes)
 161	 */
 162	if (rgn_desc->region.length <
 163	    (obj_desc->common_field.base_byte_offset + field_datum_byte_offset +
 164	     obj_desc->common_field.access_byte_width)) {
 165		if (acpi_gbl_enable_interpreter_slack) {
 166			/*
 167			 * Slack mode only:  We will go ahead and allow access to this
 168			 * field if it is within the region length rounded up to the next
 169			 * access width boundary. acpi_size cast for 64-bit compile.
 170			 */
 171			if (ACPI_ROUND_UP(rgn_desc->region.length,
 172					  obj_desc->common_field.
 173					  access_byte_width) >=
 174			    ((acpi_size) obj_desc->common_field.
 175			     base_byte_offset +
 176			     obj_desc->common_field.access_byte_width +
 177			     field_datum_byte_offset)) {
 178				return_ACPI_STATUS(AE_OK);
 179			}
 180		}
 181
 182		if (rgn_desc->region.length <
 183		    obj_desc->common_field.access_byte_width) {
 184			/*
 185			 * This is the case where the access_type (acc_word, etc.) is wider
 186			 * than the region itself.  For example, a region of length one
 187			 * byte, and a field with Dword access specified.
 188			 */
 189			ACPI_ERROR((AE_INFO,
 190				    "Field [%4.4s] access width (%u bytes) too large for region [%4.4s] (length %u)",
 191				    acpi_ut_get_node_name(obj_desc->
 192							  common_field.node),
 193				    obj_desc->common_field.access_byte_width,
 194				    acpi_ut_get_node_name(rgn_desc->region.
 195							  node),
 196				    rgn_desc->region.length));
 197		}
 198
 199		/*
 200		 * Offset rounded up to next multiple of field width
 201		 * exceeds region length, indicate an error
 202		 */
 203		ACPI_ERROR((AE_INFO,
 204			    "Field [%4.4s] Base+Offset+Width %u+%u+%u is beyond end of region [%4.4s] (length %u)",
 205			    acpi_ut_get_node_name(obj_desc->common_field.node),
 206			    obj_desc->common_field.base_byte_offset,
 207			    field_datum_byte_offset,
 208			    obj_desc->common_field.access_byte_width,
 209			    acpi_ut_get_node_name(rgn_desc->region.node),
 210			    rgn_desc->region.length));
 211
 212		return_ACPI_STATUS(AE_AML_REGION_LIMIT);
 213	}
 214
 215	return_ACPI_STATUS(AE_OK);
 216}
 217
 218/*******************************************************************************
 219 *
 220 * FUNCTION:    acpi_ex_access_region
 221 *
 222 * PARAMETERS:  obj_desc                - Field to be read
 223 *              field_datum_byte_offset - Byte offset of this datum within the
 224 *                                        parent field
 225 *              Value                   - Where to store value (must at least
 226 *                                        64 bits)
 227 *              Function                - Read or Write flag plus other region-
 228 *                                        dependent flags
 229 *
 230 * RETURN:      Status
 231 *
 232 * DESCRIPTION: Read or Write a single field datum to an Operation Region.
 233 *
 234 ******************************************************************************/
 235
 236acpi_status
 237acpi_ex_access_region(union acpi_operand_object *obj_desc,
 238		      u32 field_datum_byte_offset, u64 *value, u32 function)
 239{
 240	acpi_status status;
 241	union acpi_operand_object *rgn_desc;
 242	u32 region_offset;
 243
 244	ACPI_FUNCTION_TRACE(ex_access_region);
 245
 246	/*
 247	 * Ensure that the region operands are fully evaluated and verify
 248	 * the validity of the request
 249	 */
 250	status = acpi_ex_setup_region(obj_desc, field_datum_byte_offset);
 251	if (ACPI_FAILURE(status)) {
 252		return_ACPI_STATUS(status);
 253	}
 254
 255	/*
 256	 * The physical address of this field datum is:
 257	 *
 258	 * 1) The base of the region, plus
 259	 * 2) The base offset of the field, plus
 260	 * 3) The current offset into the field
 261	 */
 262	rgn_desc = obj_desc->common_field.region_obj;
 263	region_offset =
 264	    obj_desc->common_field.base_byte_offset + field_datum_byte_offset;
 265
 266	if ((function & ACPI_IO_MASK) == ACPI_READ) {
 267		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[READ]"));
 268	} else {
 269		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[WRITE]"));
 270	}
 271
 272	ACPI_DEBUG_PRINT_RAW((ACPI_DB_BFIELD,
 273			      " Region [%s:%X], Width %X, ByteBase %X, Offset %X at %p\n",
 274			      acpi_ut_get_region_name(rgn_desc->region.
 275						      space_id),
 276			      rgn_desc->region.space_id,
 277			      obj_desc->common_field.access_byte_width,
 278			      obj_desc->common_field.base_byte_offset,
 279			      field_datum_byte_offset, ACPI_CAST_PTR(void,
 280								     (rgn_desc->
 281								      region.
 282								      address +
 283								      region_offset))));
 284
 285	/* Invoke the appropriate address_space/op_region handler */
 286
 287	status = acpi_ev_address_space_dispatch(rgn_desc, obj_desc,
 288						function, region_offset,
 289						ACPI_MUL_8(obj_desc->
 290							   common_field.
 291							   access_byte_width),
 292						value);
 293
 294	if (ACPI_FAILURE(status)) {
 295		if (status == AE_NOT_IMPLEMENTED) {
 296			ACPI_ERROR((AE_INFO,
 297				    "Region %s (ID=%u) not implemented",
 298				    acpi_ut_get_region_name(rgn_desc->region.
 299							    space_id),
 300				    rgn_desc->region.space_id));
 301		} else if (status == AE_NOT_EXIST) {
 302			ACPI_ERROR((AE_INFO,
 303				    "Region %s (ID=%u) has no handler",
 304				    acpi_ut_get_region_name(rgn_desc->region.
 305							    space_id),
 306				    rgn_desc->region.space_id));
 307		}
 308	}
 309
 310	return_ACPI_STATUS(status);
 311}
 312
 313/*******************************************************************************
 314 *
 315 * FUNCTION:    acpi_ex_register_overflow
 316 *
 317 * PARAMETERS:  obj_desc                - Register(Field) to be written
 318 *              Value                   - Value to be stored
 319 *
 320 * RETURN:      TRUE if value overflows the field, FALSE otherwise
 321 *
 322 * DESCRIPTION: Check if a value is out of range of the field being written.
 323 *              Used to check if the values written to Index and Bank registers
 324 *              are out of range.  Normally, the value is simply truncated
 325 *              to fit the field, but this case is most likely a serious
 326 *              coding error in the ASL.
 327 *
 328 ******************************************************************************/
 329
 330static u8
 331acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value)
 332{
 333	ACPI_FUNCTION_NAME(ex_register_overflow);
 334
 335	if (obj_desc->common_field.bit_length >= ACPI_INTEGER_BIT_SIZE) {
 336		/*
 337		 * The field is large enough to hold the maximum integer, so we can
 338		 * never overflow it.
 339		 */
 340		return (FALSE);
 341	}
 342
 343	if (value >= ((u64) 1 << obj_desc->common_field.bit_length)) {
 344		/*
 345		 * The Value is larger than the maximum value that can fit into
 346		 * the register.
 347		 */
 348		ACPI_ERROR((AE_INFO,
 349			    "Index value 0x%8.8X%8.8X overflows field width 0x%X",
 350			    ACPI_FORMAT_UINT64(value),
 351			    obj_desc->common_field.bit_length));
 352
 353		return (TRUE);
 354	}
 355
 356	/* The Value will fit into the field with no truncation */
 357
 358	return (FALSE);
 359}
 360
 361/*******************************************************************************
 362 *
 363 * FUNCTION:    acpi_ex_field_datum_io
 364 *
 365 * PARAMETERS:  obj_desc                - Field to be read
 366 *              field_datum_byte_offset - Byte offset of this datum within the
 367 *                                        parent field
 368 *              Value                   - Where to store value (must be 64 bits)
 369 *              read_write              - Read or Write flag
 370 *
 371 * RETURN:      Status
 372 *
 373 * DESCRIPTION: Read or Write a single datum of a field.  The field_type is
 374 *              demultiplexed here to handle the different types of fields
 375 *              (buffer_field, region_field, index_field, bank_field)
 376 *
 377 ******************************************************************************/
 378
 379static acpi_status
 380acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
 381		       u32 field_datum_byte_offset, u64 *value, u32 read_write)
 382{
 383	acpi_status status;
 384	u64 local_value;
 385
 386	ACPI_FUNCTION_TRACE_U32(ex_field_datum_io, field_datum_byte_offset);
 387
 388	if (read_write == ACPI_READ) {
 389		if (!value) {
 390			local_value = 0;
 391
 392			/* To support reads without saving return value */
 393			value = &local_value;
 394		}
 395
 396		/* Clear the entire return buffer first, [Very Important!] */
 397
 398		*value = 0;
 399	}
 400
 401	/*
 402	 * The four types of fields are:
 403	 *
 404	 * buffer_field - Read/write from/to a Buffer
 405	 * region_field - Read/write from/to a Operation Region.
 406	 * bank_field  - Write to a Bank Register, then read/write from/to an
 407	 *               operation_region
 408	 * index_field - Write to an Index Register, then read/write from/to a
 409	 *               Data Register
 410	 */
 411	switch (obj_desc->common.type) {
 412	case ACPI_TYPE_BUFFER_FIELD:
 413		/*
 414		 * If the buffer_field arguments have not been previously evaluated,
 415		 * evaluate them now and save the results.
 416		 */
 417		if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
 418			status = acpi_ds_get_buffer_field_arguments(obj_desc);
 419			if (ACPI_FAILURE(status)) {
 420				return_ACPI_STATUS(status);
 421			}
 422		}
 423
 424		if (read_write == ACPI_READ) {
 425			/*
 426			 * Copy the data from the source buffer.
 427			 * Length is the field width in bytes.
 428			 */
 429			ACPI_MEMCPY(value,
 430				    (obj_desc->buffer_field.buffer_obj)->buffer.
 431				    pointer +
 432				    obj_desc->buffer_field.base_byte_offset +
 433				    field_datum_byte_offset,
 434				    obj_desc->common_field.access_byte_width);
 435		} else {
 436			/*
 437			 * Copy the data to the target buffer.
 438			 * Length is the field width in bytes.
 439			 */
 440			ACPI_MEMCPY((obj_desc->buffer_field.buffer_obj)->buffer.
 441				    pointer +
 442				    obj_desc->buffer_field.base_byte_offset +
 443				    field_datum_byte_offset, value,
 444				    obj_desc->common_field.access_byte_width);
 445		}
 446
 447		status = AE_OK;
 448		break;
 449
 450	case ACPI_TYPE_LOCAL_BANK_FIELD:
 451
 452		/*
 453		 * Ensure that the bank_value is not beyond the capacity of
 454		 * the register
 455		 */
 456		if (acpi_ex_register_overflow(obj_desc->bank_field.bank_obj,
 457					      (u64) obj_desc->bank_field.
 458					      value)) {
 459			return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
 460		}
 461
 462		/*
 463		 * For bank_fields, we must write the bank_value to the bank_register
 464		 * (itself a region_field) before we can access the data.
 465		 */
 466		status =
 467		    acpi_ex_insert_into_field(obj_desc->bank_field.bank_obj,
 468					      &obj_desc->bank_field.value,
 469					      sizeof(obj_desc->bank_field.
 470						     value));
 471		if (ACPI_FAILURE(status)) {
 472			return_ACPI_STATUS(status);
 473		}
 474
 475		/*
 476		 * Now that the Bank has been selected, fall through to the
 477		 * region_field case and write the datum to the Operation Region
 478		 */
 479
 480		/*lint -fallthrough */
 481
 482	case ACPI_TYPE_LOCAL_REGION_FIELD:
 483		/*
 484		 * For simple region_fields, we just directly access the owning
 485		 * Operation Region.
 486		 */
 487		status =
 488		    acpi_ex_access_region(obj_desc, field_datum_byte_offset,
 489					  value, read_write);
 490		break;
 491
 492	case ACPI_TYPE_LOCAL_INDEX_FIELD:
 493
 494		/*
 495		 * Ensure that the index_value is not beyond the capacity of
 496		 * the register
 497		 */
 498		if (acpi_ex_register_overflow(obj_desc->index_field.index_obj,
 499					      (u64) obj_desc->index_field.
 500					      value)) {
 501			return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
 502		}
 503
 504		/* Write the index value to the index_register (itself a region_field) */
 505
 506		field_datum_byte_offset += obj_desc->index_field.value;
 507
 508		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 509				  "Write to Index Register: Value %8.8X\n",
 510				  field_datum_byte_offset));
 511
 512		status =
 513		    acpi_ex_insert_into_field(obj_desc->index_field.index_obj,
 514					      &field_datum_byte_offset,
 515					      sizeof(field_datum_byte_offset));
 516		if (ACPI_FAILURE(status)) {
 517			return_ACPI_STATUS(status);
 518		}
 519
 520		if (read_write == ACPI_READ) {
 521
 522			/* Read the datum from the data_register */
 523
 524			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 525					  "Read from Data Register\n"));
 526
 527			status =
 528			    acpi_ex_extract_from_field(obj_desc->index_field.
 529						       data_obj, value,
 530						       sizeof(u64));
 531		} else {
 532			/* Write the datum to the data_register */
 533
 534			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 535					  "Write to Data Register: Value %8.8X%8.8X\n",
 536					  ACPI_FORMAT_UINT64(*value)));
 537
 538			status =
 539			    acpi_ex_insert_into_field(obj_desc->index_field.
 540						      data_obj, value,
 541						      sizeof(u64));
 542		}
 543		break;
 544
 545	default:
 546
 547		ACPI_ERROR((AE_INFO, "Wrong object type in field I/O %u",
 548			    obj_desc->common.type));
 549		status = AE_AML_INTERNAL;
 550		break;
 551	}
 552
 553	if (ACPI_SUCCESS(status)) {
 554		if (read_write == ACPI_READ) {
 555			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 556					  "Value Read %8.8X%8.8X, Width %u\n",
 557					  ACPI_FORMAT_UINT64(*value),
 558					  obj_desc->common_field.
 559					  access_byte_width));
 560		} else {
 561			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 562					  "Value Written %8.8X%8.8X, Width %u\n",
 563					  ACPI_FORMAT_UINT64(*value),
 564					  obj_desc->common_field.
 565					  access_byte_width));
 566		}
 567	}
 568
 569	return_ACPI_STATUS(status);
 570}
 571
 572/*******************************************************************************
 573 *
 574 * FUNCTION:    acpi_ex_write_with_update_rule
 575 *
 576 * PARAMETERS:  obj_desc                - Field to be written
 577 *              Mask                    - bitmask within field datum
 578 *              field_value             - Value to write
 579 *              field_datum_byte_offset - Offset of datum within field
 580 *
 581 * RETURN:      Status
 582 *
 583 * DESCRIPTION: Apply the field update rule to a field write
 584 *
 585 ******************************************************************************/
 586
 587acpi_status
 588acpi_ex_write_with_update_rule(union acpi_operand_object *obj_desc,
 589			       u64 mask,
 590			       u64 field_value, u32 field_datum_byte_offset)
 591{
 592	acpi_status status = AE_OK;
 593	u64 merged_value;
 594	u64 current_value;
 595
 596	ACPI_FUNCTION_TRACE_U32(ex_write_with_update_rule, mask);
 597
 598	/* Start with the new bits  */
 599
 600	merged_value = field_value;
 601
 602	/* If the mask is all ones, we don't need to worry about the update rule */
 603
 604	if (mask != ACPI_UINT64_MAX) {
 605
 606		/* Decode the update rule */
 607
 608		switch (obj_desc->common_field.
 609			field_flags & AML_FIELD_UPDATE_RULE_MASK) {
 610		case AML_FIELD_UPDATE_PRESERVE:
 611			/*
 612			 * Check if update rule needs to be applied (not if mask is all
 613			 * ones)  The left shift drops the bits we want to ignore.
 614			 */
 615			if ((~mask << (ACPI_MUL_8(sizeof(mask)) -
 616				       ACPI_MUL_8(obj_desc->common_field.
 617						  access_byte_width))) != 0) {
 618				/*
 619				 * Read the current contents of the byte/word/dword containing
 620				 * the field, and merge with the new field value.
 621				 */
 622				status =
 623				    acpi_ex_field_datum_io(obj_desc,
 624							   field_datum_byte_offset,
 625							   &current_value,
 626							   ACPI_READ);
 627				if (ACPI_FAILURE(status)) {
 628					return_ACPI_STATUS(status);
 629				}
 630
 631				merged_value |= (current_value & ~mask);
 632			}
 633			break;
 634
 635		case AML_FIELD_UPDATE_WRITE_AS_ONES:
 636
 637			/* Set positions outside the field to all ones */
 638
 639			merged_value |= ~mask;
 640			break;
 641
 642		case AML_FIELD_UPDATE_WRITE_AS_ZEROS:
 643
 644			/* Set positions outside the field to all zeros */
 645
 646			merged_value &= mask;
 647			break;
 648
 649		default:
 650
 651			ACPI_ERROR((AE_INFO,
 652				    "Unknown UpdateRule value: 0x%X",
 653				    (obj_desc->common_field.
 654				     field_flags &
 655				     AML_FIELD_UPDATE_RULE_MASK)));
 656			return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
 657		}
 658	}
 659
 660	ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 661			  "Mask %8.8X%8.8X, DatumOffset %X, Width %X, Value %8.8X%8.8X, MergedValue %8.8X%8.8X\n",
 662			  ACPI_FORMAT_UINT64(mask),
 663			  field_datum_byte_offset,
 664			  obj_desc->common_field.access_byte_width,
 665			  ACPI_FORMAT_UINT64(field_value),
 666			  ACPI_FORMAT_UINT64(merged_value)));
 667
 668	/* Write the merged value */
 669
 670	status = acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset,
 671					&merged_value, ACPI_WRITE);
 672
 673	return_ACPI_STATUS(status);
 674}
 675
 676/*******************************************************************************
 677 *
 678 * FUNCTION:    acpi_ex_extract_from_field
 679 *
 680 * PARAMETERS:  obj_desc            - Field to be read
 681 *              Buffer              - Where to store the field data
 682 *              buffer_length       - Length of Buffer
 683 *
 684 * RETURN:      Status
 685 *
 686 * DESCRIPTION: Retrieve the current value of the given field
 687 *
 688 ******************************************************************************/
 689
 690acpi_status
 691acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
 692			   void *buffer, u32 buffer_length)
 693{
 694	acpi_status status;
 695	u64 raw_datum;
 696	u64 merged_datum;
 697	u32 field_offset = 0;
 698	u32 buffer_offset = 0;
 699	u32 buffer_tail_bits;
 700	u32 datum_count;
 701	u32 field_datum_count;
 702	u32 access_bit_width;
 703	u32 i;
 704
 705	ACPI_FUNCTION_TRACE(ex_extract_from_field);
 706
 707	/* Validate target buffer and clear it */
 708
 709	if (buffer_length <
 710	    ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length)) {
 711		ACPI_ERROR((AE_INFO,
 712			    "Field size %u (bits) is too large for buffer (%u)",
 713			    obj_desc->common_field.bit_length, buffer_length));
 714
 715		return_ACPI_STATUS(AE_BUFFER_OVERFLOW);
 716	}
 717
 718	ACPI_MEMSET(buffer, 0, buffer_length);
 719	access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
 720
 721	/* Handle the simple case here */
 722
 723	if ((obj_desc->common_field.start_field_bit_offset == 0) &&
 724	    (obj_desc->common_field.bit_length == access_bit_width)) {
 725		status = acpi_ex_field_datum_io(obj_desc, 0, buffer, ACPI_READ);
 
 
 
 
 
 
 
 
 
 
 
 
 726		return_ACPI_STATUS(status);
 727	}
 728
 729/* TBD: Move to common setup code */
 730
 731	/* Field algorithm is limited to sizeof(u64), truncate if needed */
 732
 733	if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
 734		obj_desc->common_field.access_byte_width = sizeof(u64);
 735		access_bit_width = sizeof(u64) * 8;
 736	}
 737
 738	/* Compute the number of datums (access width data items) */
 739
 740	datum_count =
 741	    ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
 742			     access_bit_width);
 743
 744	field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
 745					     obj_desc->common_field.
 746					     start_field_bit_offset,
 747					     access_bit_width);
 748
 749	/* Priming read from the field */
 750
 751	status =
 752	    acpi_ex_field_datum_io(obj_desc, field_offset, &raw_datum,
 753				   ACPI_READ);
 754	if (ACPI_FAILURE(status)) {
 755		return_ACPI_STATUS(status);
 756	}
 757	merged_datum =
 758	    raw_datum >> obj_desc->common_field.start_field_bit_offset;
 759
 760	/* Read the rest of the field */
 761
 762	for (i = 1; i < field_datum_count; i++) {
 763
 764		/* Get next input datum from the field */
 765
 766		field_offset += obj_desc->common_field.access_byte_width;
 767		status = acpi_ex_field_datum_io(obj_desc, field_offset,
 768						&raw_datum, ACPI_READ);
 769		if (ACPI_FAILURE(status)) {
 770			return_ACPI_STATUS(status);
 771		}
 772
 773		/*
 774		 * Merge with previous datum if necessary.
 775		 *
 776		 * Note: Before the shift, check if the shift value will be larger than
 777		 * the integer size. If so, there is no need to perform the operation.
 778		 * This avoids the differences in behavior between different compilers
 779		 * concerning shift values larger than the target data width.
 780		 */
 781		if (access_bit_width -
 782		    obj_desc->common_field.start_field_bit_offset <
 783		    ACPI_INTEGER_BIT_SIZE) {
 784			merged_datum |=
 785			    raw_datum << (access_bit_width -
 786					  obj_desc->common_field.
 787					  start_field_bit_offset);
 788		}
 789
 790		if (i == datum_count) {
 791			break;
 792		}
 793
 794		/* Write merged datum to target buffer */
 795
 796		ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
 797			    ACPI_MIN(obj_desc->common_field.access_byte_width,
 798				     buffer_length - buffer_offset));
 799
 800		buffer_offset += obj_desc->common_field.access_byte_width;
 801		merged_datum =
 802		    raw_datum >> obj_desc->common_field.start_field_bit_offset;
 803	}
 804
 805	/* Mask off any extra bits in the last datum */
 806
 807	buffer_tail_bits = obj_desc->common_field.bit_length % access_bit_width;
 808	if (buffer_tail_bits) {
 809		merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
 810	}
 811
 812	/* Write the last datum to the buffer */
 813
 814	ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
 815		    ACPI_MIN(obj_desc->common_field.access_byte_width,
 816			     buffer_length - buffer_offset));
 817
 818	return_ACPI_STATUS(AE_OK);
 819}
 820
 821/*******************************************************************************
 822 *
 823 * FUNCTION:    acpi_ex_insert_into_field
 824 *
 825 * PARAMETERS:  obj_desc            - Field to be written
 826 *              Buffer              - Data to be written
 827 *              buffer_length       - Length of Buffer
 828 *
 829 * RETURN:      Status
 830 *
 831 * DESCRIPTION: Store the Buffer contents into the given field
 832 *
 833 ******************************************************************************/
 834
 835acpi_status
 836acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
 837			  void *buffer, u32 buffer_length)
 838{
 839	void *new_buffer;
 840	acpi_status status;
 841	u64 mask;
 842	u64 width_mask;
 843	u64 merged_datum;
 844	u64 raw_datum = 0;
 845	u32 field_offset = 0;
 846	u32 buffer_offset = 0;
 847	u32 buffer_tail_bits;
 848	u32 datum_count;
 849	u32 field_datum_count;
 850	u32 access_bit_width;
 851	u32 required_length;
 852	u32 i;
 853
 854	ACPI_FUNCTION_TRACE(ex_insert_into_field);
 855
 856	/* Validate input buffer */
 857
 858	new_buffer = NULL;
 859	required_length =
 860	    ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length);
 861	/*
 862	 * We must have a buffer that is at least as long as the field
 863	 * we are writing to.  This is because individual fields are
 864	 * indivisible and partial writes are not supported -- as per
 865	 * the ACPI specification.
 866	 */
 867	if (buffer_length < required_length) {
 868
 869		/* We need to create a new buffer */
 870
 871		new_buffer = ACPI_ALLOCATE_ZEROED(required_length);
 872		if (!new_buffer) {
 873			return_ACPI_STATUS(AE_NO_MEMORY);
 874		}
 875
 876		/*
 877		 * Copy the original data to the new buffer, starting
 878		 * at Byte zero.  All unused (upper) bytes of the
 879		 * buffer will be 0.
 880		 */
 881		ACPI_MEMCPY((char *)new_buffer, (char *)buffer, buffer_length);
 882		buffer = new_buffer;
 883		buffer_length = required_length;
 884	}
 885
 886/* TBD: Move to common setup code */
 887
 888	/* Algo is limited to sizeof(u64), so cut the access_byte_width */
 889	if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
 890		obj_desc->common_field.access_byte_width = sizeof(u64);
 891	}
 892
 893	access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
 894
 895	/*
 896	 * Create the bitmasks used for bit insertion.
 897	 * Note: This if/else is used to bypass compiler differences with the
 898	 * shift operator
 899	 */
 900	if (access_bit_width == ACPI_INTEGER_BIT_SIZE) {
 901		width_mask = ACPI_UINT64_MAX;
 902	} else {
 903		width_mask = ACPI_MASK_BITS_ABOVE(access_bit_width);
 904	}
 905
 906	mask = width_mask &
 907	    ACPI_MASK_BITS_BELOW(obj_desc->common_field.start_field_bit_offset);
 908
 909	/* Compute the number of datums (access width data items) */
 910
 911	datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
 912				       access_bit_width);
 913
 914	field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
 915					     obj_desc->common_field.
 916					     start_field_bit_offset,
 917					     access_bit_width);
 918
 919	/* Get initial Datum from the input buffer */
 920
 921	ACPI_MEMCPY(&raw_datum, buffer,
 922		    ACPI_MIN(obj_desc->common_field.access_byte_width,
 923			     buffer_length - buffer_offset));
 924
 925	merged_datum =
 926	    raw_datum << obj_desc->common_field.start_field_bit_offset;
 927
 928	/* Write the entire field */
 929
 930	for (i = 1; i < field_datum_count; i++) {
 931
 932		/* Write merged datum to the target field */
 933
 934		merged_datum &= mask;
 935		status = acpi_ex_write_with_update_rule(obj_desc, mask,
 936							merged_datum,
 937							field_offset);
 938		if (ACPI_FAILURE(status)) {
 939			goto exit;
 940		}
 941
 942		field_offset += obj_desc->common_field.access_byte_width;
 943
 944		/*
 945		 * Start new output datum by merging with previous input datum
 946		 * if necessary.
 947		 *
 948		 * Note: Before the shift, check if the shift value will be larger than
 949		 * the integer size. If so, there is no need to perform the operation.
 950		 * This avoids the differences in behavior between different compilers
 951		 * concerning shift values larger than the target data width.
 952		 */
 953		if ((access_bit_width -
 954		     obj_desc->common_field.start_field_bit_offset) <
 955		    ACPI_INTEGER_BIT_SIZE) {
 956			merged_datum =
 957			    raw_datum >> (access_bit_width -
 958					  obj_desc->common_field.
 959					  start_field_bit_offset);
 960		} else {
 961			merged_datum = 0;
 962		}
 963
 964		mask = width_mask;
 965
 966		if (i == datum_count) {
 967			break;
 968		}
 969
 970		/* Get the next input datum from the buffer */
 971
 972		buffer_offset += obj_desc->common_field.access_byte_width;
 973		ACPI_MEMCPY(&raw_datum, ((char *)buffer) + buffer_offset,
 974			    ACPI_MIN(obj_desc->common_field.access_byte_width,
 975				     buffer_length - buffer_offset));
 976
 977		merged_datum |=
 978		    raw_datum << obj_desc->common_field.start_field_bit_offset;
 979	}
 980
 981	/* Mask off any extra bits in the last datum */
 982
 983	buffer_tail_bits = (obj_desc->common_field.bit_length +
 984			    obj_desc->common_field.start_field_bit_offset) %
 985	    access_bit_width;
 986	if (buffer_tail_bits) {
 987		mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
 988	}
 989
 990	/* Write the last datum to the field */
 991
 992	merged_datum &= mask;
 993	status = acpi_ex_write_with_update_rule(obj_desc,
 994						mask, merged_datum,
 995						field_offset);
 996
 997      exit:
 998	/* Free temporary buffer if we used one */
 999
1000	if (new_buffer) {
1001		ACPI_FREE(new_buffer);
1002	}
1003	return_ACPI_STATUS(status);
1004}
v3.15
   1/******************************************************************************
   2 *
   3 * Module Name: exfldio - Aml Field I/O
   4 *
   5 *****************************************************************************/
   6
   7/*
   8 * Copyright (C) 2000 - 2014, Intel Corp.
   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#include <acpi/acpi.h>
  45#include "accommon.h"
  46#include "acinterp.h"
  47#include "amlcode.h"
  48#include "acevents.h"
  49#include "acdispat.h"
  50
  51#define _COMPONENT          ACPI_EXECUTER
  52ACPI_MODULE_NAME("exfldio")
  53
  54/* Local prototypes */
  55static acpi_status
  56acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
  57		       u32 field_datum_byte_offset, u64 *value, u32 read_write);
 
  58
  59static u8
  60acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value);
  61
  62static acpi_status
  63acpi_ex_setup_region(union acpi_operand_object *obj_desc,
  64		     u32 field_datum_byte_offset);
  65
  66/*******************************************************************************
  67 *
  68 * FUNCTION:    acpi_ex_setup_region
  69 *
  70 * PARAMETERS:  obj_desc                - Field to be read or written
  71 *              field_datum_byte_offset - Byte offset of this datum within the
  72 *                                        parent field
  73 *
  74 * RETURN:      Status
  75 *
  76 * DESCRIPTION: Common processing for acpi_ex_extract_from_field and
  77 *              acpi_ex_insert_into_field. Initialize the Region if necessary and
  78 *              validate the request.
  79 *
  80 ******************************************************************************/
  81
  82static acpi_status
  83acpi_ex_setup_region(union acpi_operand_object *obj_desc,
  84		     u32 field_datum_byte_offset)
  85{
  86	acpi_status status = AE_OK;
  87	union acpi_operand_object *rgn_desc;
  88	u8 space_id;
  89
  90	ACPI_FUNCTION_TRACE_U32(ex_setup_region, field_datum_byte_offset);
  91
  92	rgn_desc = obj_desc->common_field.region_obj;
  93
  94	/* We must have a valid region */
  95
  96	if (rgn_desc->common.type != ACPI_TYPE_REGION) {
  97		ACPI_ERROR((AE_INFO, "Needed Region, found type 0x%X (%s)",
  98			    rgn_desc->common.type,
  99			    acpi_ut_get_object_type_name(rgn_desc)));
 100
 101		return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
 102	}
 103
 104	space_id = rgn_desc->region.space_id;
 105
 106	/* Validate the Space ID */
 107
 108	if (!acpi_is_valid_space_id(space_id)) {
 109		ACPI_ERROR((AE_INFO,
 110			    "Invalid/unknown Address Space ID: 0x%2.2X",
 111			    space_id));
 112		return_ACPI_STATUS(AE_AML_INVALID_SPACE_ID);
 113	}
 114
 115	/*
 116	 * If the Region Address and Length have not been previously evaluated,
 117	 * evaluate them now and save the results.
 118	 */
 119	if (!(rgn_desc->common.flags & AOPOBJ_DATA_VALID)) {
 120		status = acpi_ds_get_region_arguments(rgn_desc);
 121		if (ACPI_FAILURE(status)) {
 122			return_ACPI_STATUS(status);
 123		}
 124	}
 125
 
 
 
 
 
 
 126	/*
 127	 * Exit now for SMBus, GSBus or IPMI address space, it has a non-linear
 128	 * address space and the request cannot be directly validated
 129	 */
 130	if (space_id == ACPI_ADR_SPACE_SMBUS ||
 131	    space_id == ACPI_ADR_SPACE_GSBUS ||
 132	    space_id == ACPI_ADR_SPACE_IPMI) {
 133
 134		/* SMBus or IPMI has a non-linear address space */
 135
 136		return_ACPI_STATUS(AE_OK);
 137	}
 138#ifdef ACPI_UNDER_DEVELOPMENT
 139	/*
 140	 * If the Field access is any_acc, we can now compute the optimal
 141	 * access (because we know know the length of the parent region)
 142	 */
 143	if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
 144		if (ACPI_FAILURE(status)) {
 145			return_ACPI_STATUS(status);
 146		}
 147	}
 148#endif
 149
 150	/*
 151	 * Validate the request. The entire request from the byte offset for a
 152	 * length of one field datum (access width) must fit within the region.
 153	 * (Region length is specified in bytes)
 154	 */
 155	if (rgn_desc->region.length <
 156	    (obj_desc->common_field.base_byte_offset + field_datum_byte_offset +
 157	     obj_desc->common_field.access_byte_width)) {
 158		if (acpi_gbl_enable_interpreter_slack) {
 159			/*
 160			 * Slack mode only:  We will go ahead and allow access to this
 161			 * field if it is within the region length rounded up to the next
 162			 * access width boundary. acpi_size cast for 64-bit compile.
 163			 */
 164			if (ACPI_ROUND_UP(rgn_desc->region.length,
 165					  obj_desc->common_field.
 166					  access_byte_width) >=
 167			    ((acpi_size) obj_desc->common_field.
 168			     base_byte_offset +
 169			     obj_desc->common_field.access_byte_width +
 170			     field_datum_byte_offset)) {
 171				return_ACPI_STATUS(AE_OK);
 172			}
 173		}
 174
 175		if (rgn_desc->region.length <
 176		    obj_desc->common_field.access_byte_width) {
 177			/*
 178			 * This is the case where the access_type (acc_word, etc.) is wider
 179			 * than the region itself. For example, a region of length one
 180			 * byte, and a field with Dword access specified.
 181			 */
 182			ACPI_ERROR((AE_INFO,
 183				    "Field [%4.4s] access width (%u bytes) too large for region [%4.4s] (length %u)",
 184				    acpi_ut_get_node_name(obj_desc->
 185							  common_field.node),
 186				    obj_desc->common_field.access_byte_width,
 187				    acpi_ut_get_node_name(rgn_desc->region.
 188							  node),
 189				    rgn_desc->region.length));
 190		}
 191
 192		/*
 193		 * Offset rounded up to next multiple of field width
 194		 * exceeds region length, indicate an error
 195		 */
 196		ACPI_ERROR((AE_INFO,
 197			    "Field [%4.4s] Base+Offset+Width %u+%u+%u is beyond end of region [%4.4s] (length %u)",
 198			    acpi_ut_get_node_name(obj_desc->common_field.node),
 199			    obj_desc->common_field.base_byte_offset,
 200			    field_datum_byte_offset,
 201			    obj_desc->common_field.access_byte_width,
 202			    acpi_ut_get_node_name(rgn_desc->region.node),
 203			    rgn_desc->region.length));
 204
 205		return_ACPI_STATUS(AE_AML_REGION_LIMIT);
 206	}
 207
 208	return_ACPI_STATUS(AE_OK);
 209}
 210
 211/*******************************************************************************
 212 *
 213 * FUNCTION:    acpi_ex_access_region
 214 *
 215 * PARAMETERS:  obj_desc                - Field to be read
 216 *              field_datum_byte_offset - Byte offset of this datum within the
 217 *                                        parent field
 218 *              value                   - Where to store value (must at least
 219 *                                        64 bits)
 220 *              function                - Read or Write flag plus other region-
 221 *                                        dependent flags
 222 *
 223 * RETURN:      Status
 224 *
 225 * DESCRIPTION: Read or Write a single field datum to an Operation Region.
 226 *
 227 ******************************************************************************/
 228
 229acpi_status
 230acpi_ex_access_region(union acpi_operand_object *obj_desc,
 231		      u32 field_datum_byte_offset, u64 *value, u32 function)
 232{
 233	acpi_status status;
 234	union acpi_operand_object *rgn_desc;
 235	u32 region_offset;
 236
 237	ACPI_FUNCTION_TRACE(ex_access_region);
 238
 239	/*
 240	 * Ensure that the region operands are fully evaluated and verify
 241	 * the validity of the request
 242	 */
 243	status = acpi_ex_setup_region(obj_desc, field_datum_byte_offset);
 244	if (ACPI_FAILURE(status)) {
 245		return_ACPI_STATUS(status);
 246	}
 247
 248	/*
 249	 * The physical address of this field datum is:
 250	 *
 251	 * 1) The base of the region, plus
 252	 * 2) The base offset of the field, plus
 253	 * 3) The current offset into the field
 254	 */
 255	rgn_desc = obj_desc->common_field.region_obj;
 256	region_offset =
 257	    obj_desc->common_field.base_byte_offset + field_datum_byte_offset;
 258
 259	if ((function & ACPI_IO_MASK) == ACPI_READ) {
 260		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[READ]"));
 261	} else {
 262		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[WRITE]"));
 263	}
 264
 265	ACPI_DEBUG_PRINT_RAW((ACPI_DB_BFIELD,
 266			      " Region [%s:%X], Width %X, ByteBase %X, Offset %X at %p\n",
 267			      acpi_ut_get_region_name(rgn_desc->region.
 268						      space_id),
 269			      rgn_desc->region.space_id,
 270			      obj_desc->common_field.access_byte_width,
 271			      obj_desc->common_field.base_byte_offset,
 272			      field_datum_byte_offset, ACPI_CAST_PTR(void,
 273								     (rgn_desc->
 274								      region.
 275								      address +
 276								      region_offset))));
 277
 278	/* Invoke the appropriate address_space/op_region handler */
 279
 280	status = acpi_ev_address_space_dispatch(rgn_desc, obj_desc,
 281						function, region_offset,
 282						ACPI_MUL_8(obj_desc->
 283							   common_field.
 284							   access_byte_width),
 285						value);
 286
 287	if (ACPI_FAILURE(status)) {
 288		if (status == AE_NOT_IMPLEMENTED) {
 289			ACPI_ERROR((AE_INFO,
 290				    "Region %s (ID=%u) not implemented",
 291				    acpi_ut_get_region_name(rgn_desc->region.
 292							    space_id),
 293				    rgn_desc->region.space_id));
 294		} else if (status == AE_NOT_EXIST) {
 295			ACPI_ERROR((AE_INFO,
 296				    "Region %s (ID=%u) has no handler",
 297				    acpi_ut_get_region_name(rgn_desc->region.
 298							    space_id),
 299				    rgn_desc->region.space_id));
 300		}
 301	}
 302
 303	return_ACPI_STATUS(status);
 304}
 305
 306/*******************************************************************************
 307 *
 308 * FUNCTION:    acpi_ex_register_overflow
 309 *
 310 * PARAMETERS:  obj_desc                - Register(Field) to be written
 311 *              value                   - Value to be stored
 312 *
 313 * RETURN:      TRUE if value overflows the field, FALSE otherwise
 314 *
 315 * DESCRIPTION: Check if a value is out of range of the field being written.
 316 *              Used to check if the values written to Index and Bank registers
 317 *              are out of range. Normally, the value is simply truncated
 318 *              to fit the field, but this case is most likely a serious
 319 *              coding error in the ASL.
 320 *
 321 ******************************************************************************/
 322
 323static u8
 324acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value)
 325{
 
 326
 327	if (obj_desc->common_field.bit_length >= ACPI_INTEGER_BIT_SIZE) {
 328		/*
 329		 * The field is large enough to hold the maximum integer, so we can
 330		 * never overflow it.
 331		 */
 332		return (FALSE);
 333	}
 334
 335	if (value >= ((u64) 1 << obj_desc->common_field.bit_length)) {
 336		/*
 337		 * The Value is larger than the maximum value that can fit into
 338		 * the register.
 339		 */
 340		ACPI_ERROR((AE_INFO,
 341			    "Index value 0x%8.8X%8.8X overflows field width 0x%X",
 342			    ACPI_FORMAT_UINT64(value),
 343			    obj_desc->common_field.bit_length));
 344
 345		return (TRUE);
 346	}
 347
 348	/* The Value will fit into the field with no truncation */
 349
 350	return (FALSE);
 351}
 352
 353/*******************************************************************************
 354 *
 355 * FUNCTION:    acpi_ex_field_datum_io
 356 *
 357 * PARAMETERS:  obj_desc                - Field to be read
 358 *              field_datum_byte_offset - Byte offset of this datum within the
 359 *                                        parent field
 360 *              value                   - Where to store value (must be 64 bits)
 361 *              read_write              - Read or Write flag
 362 *
 363 * RETURN:      Status
 364 *
 365 * DESCRIPTION: Read or Write a single datum of a field. The field_type is
 366 *              demultiplexed here to handle the different types of fields
 367 *              (buffer_field, region_field, index_field, bank_field)
 368 *
 369 ******************************************************************************/
 370
 371static acpi_status
 372acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
 373		       u32 field_datum_byte_offset, u64 *value, u32 read_write)
 374{
 375	acpi_status status;
 376	u64 local_value;
 377
 378	ACPI_FUNCTION_TRACE_U32(ex_field_datum_io, field_datum_byte_offset);
 379
 380	if (read_write == ACPI_READ) {
 381		if (!value) {
 382			local_value = 0;
 383
 384			/* To support reads without saving return value */
 385			value = &local_value;
 386		}
 387
 388		/* Clear the entire return buffer first, [Very Important!] */
 389
 390		*value = 0;
 391	}
 392
 393	/*
 394	 * The four types of fields are:
 395	 *
 396	 * buffer_field - Read/write from/to a Buffer
 397	 * region_field - Read/write from/to a Operation Region.
 398	 * bank_field  - Write to a Bank Register, then read/write from/to an
 399	 *               operation_region
 400	 * index_field - Write to an Index Register, then read/write from/to a
 401	 *               Data Register
 402	 */
 403	switch (obj_desc->common.type) {
 404	case ACPI_TYPE_BUFFER_FIELD:
 405		/*
 406		 * If the buffer_field arguments have not been previously evaluated,
 407		 * evaluate them now and save the results.
 408		 */
 409		if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
 410			status = acpi_ds_get_buffer_field_arguments(obj_desc);
 411			if (ACPI_FAILURE(status)) {
 412				return_ACPI_STATUS(status);
 413			}
 414		}
 415
 416		if (read_write == ACPI_READ) {
 417			/*
 418			 * Copy the data from the source buffer.
 419			 * Length is the field width in bytes.
 420			 */
 421			ACPI_MEMCPY(value,
 422				    (obj_desc->buffer_field.buffer_obj)->buffer.
 423				    pointer +
 424				    obj_desc->buffer_field.base_byte_offset +
 425				    field_datum_byte_offset,
 426				    obj_desc->common_field.access_byte_width);
 427		} else {
 428			/*
 429			 * Copy the data to the target buffer.
 430			 * Length is the field width in bytes.
 431			 */
 432			ACPI_MEMCPY((obj_desc->buffer_field.buffer_obj)->buffer.
 433				    pointer +
 434				    obj_desc->buffer_field.base_byte_offset +
 435				    field_datum_byte_offset, value,
 436				    obj_desc->common_field.access_byte_width);
 437		}
 438
 439		status = AE_OK;
 440		break;
 441
 442	case ACPI_TYPE_LOCAL_BANK_FIELD:
 
 443		/*
 444		 * Ensure that the bank_value is not beyond the capacity of
 445		 * the register
 446		 */
 447		if (acpi_ex_register_overflow(obj_desc->bank_field.bank_obj,
 448					      (u64) obj_desc->bank_field.
 449					      value)) {
 450			return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
 451		}
 452
 453		/*
 454		 * For bank_fields, we must write the bank_value to the bank_register
 455		 * (itself a region_field) before we can access the data.
 456		 */
 457		status =
 458		    acpi_ex_insert_into_field(obj_desc->bank_field.bank_obj,
 459					      &obj_desc->bank_field.value,
 460					      sizeof(obj_desc->bank_field.
 461						     value));
 462		if (ACPI_FAILURE(status)) {
 463			return_ACPI_STATUS(status);
 464		}
 465
 466		/*
 467		 * Now that the Bank has been selected, fall through to the
 468		 * region_field case and write the datum to the Operation Region
 469		 */
 470
 471		/*lint -fallthrough */
 472
 473	case ACPI_TYPE_LOCAL_REGION_FIELD:
 474		/*
 475		 * For simple region_fields, we just directly access the owning
 476		 * Operation Region.
 477		 */
 478		status =
 479		    acpi_ex_access_region(obj_desc, field_datum_byte_offset,
 480					  value, read_write);
 481		break;
 482
 483	case ACPI_TYPE_LOCAL_INDEX_FIELD:
 
 484		/*
 485		 * Ensure that the index_value is not beyond the capacity of
 486		 * the register
 487		 */
 488		if (acpi_ex_register_overflow(obj_desc->index_field.index_obj,
 489					      (u64) obj_desc->index_field.
 490					      value)) {
 491			return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
 492		}
 493
 494		/* Write the index value to the index_register (itself a region_field) */
 495
 496		field_datum_byte_offset += obj_desc->index_field.value;
 497
 498		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 499				  "Write to Index Register: Value %8.8X\n",
 500				  field_datum_byte_offset));
 501
 502		status =
 503		    acpi_ex_insert_into_field(obj_desc->index_field.index_obj,
 504					      &field_datum_byte_offset,
 505					      sizeof(field_datum_byte_offset));
 506		if (ACPI_FAILURE(status)) {
 507			return_ACPI_STATUS(status);
 508		}
 509
 510		if (read_write == ACPI_READ) {
 511
 512			/* Read the datum from the data_register */
 513
 514			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 515					  "Read from Data Register\n"));
 516
 517			status =
 518			    acpi_ex_extract_from_field(obj_desc->index_field.
 519						       data_obj, value,
 520						       sizeof(u64));
 521		} else {
 522			/* Write the datum to the data_register */
 523
 524			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 525					  "Write to Data Register: Value %8.8X%8.8X\n",
 526					  ACPI_FORMAT_UINT64(*value)));
 527
 528			status =
 529			    acpi_ex_insert_into_field(obj_desc->index_field.
 530						      data_obj, value,
 531						      sizeof(u64));
 532		}
 533		break;
 534
 535	default:
 536
 537		ACPI_ERROR((AE_INFO, "Wrong object type in field I/O %u",
 538			    obj_desc->common.type));
 539		status = AE_AML_INTERNAL;
 540		break;
 541	}
 542
 543	if (ACPI_SUCCESS(status)) {
 544		if (read_write == ACPI_READ) {
 545			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 546					  "Value Read %8.8X%8.8X, Width %u\n",
 547					  ACPI_FORMAT_UINT64(*value),
 548					  obj_desc->common_field.
 549					  access_byte_width));
 550		} else {
 551			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 552					  "Value Written %8.8X%8.8X, Width %u\n",
 553					  ACPI_FORMAT_UINT64(*value),
 554					  obj_desc->common_field.
 555					  access_byte_width));
 556		}
 557	}
 558
 559	return_ACPI_STATUS(status);
 560}
 561
 562/*******************************************************************************
 563 *
 564 * FUNCTION:    acpi_ex_write_with_update_rule
 565 *
 566 * PARAMETERS:  obj_desc                - Field to be written
 567 *              mask                    - bitmask within field datum
 568 *              field_value             - Value to write
 569 *              field_datum_byte_offset - Offset of datum within field
 570 *
 571 * RETURN:      Status
 572 *
 573 * DESCRIPTION: Apply the field update rule to a field write
 574 *
 575 ******************************************************************************/
 576
 577acpi_status
 578acpi_ex_write_with_update_rule(union acpi_operand_object *obj_desc,
 579			       u64 mask,
 580			       u64 field_value, u32 field_datum_byte_offset)
 581{
 582	acpi_status status = AE_OK;
 583	u64 merged_value;
 584	u64 current_value;
 585
 586	ACPI_FUNCTION_TRACE_U32(ex_write_with_update_rule, mask);
 587
 588	/* Start with the new bits  */
 589
 590	merged_value = field_value;
 591
 592	/* If the mask is all ones, we don't need to worry about the update rule */
 593
 594	if (mask != ACPI_UINT64_MAX) {
 595
 596		/* Decode the update rule */
 597
 598		switch (obj_desc->common_field.
 599			field_flags & AML_FIELD_UPDATE_RULE_MASK) {
 600		case AML_FIELD_UPDATE_PRESERVE:
 601			/*
 602			 * Check if update rule needs to be applied (not if mask is all
 603			 * ones)  The left shift drops the bits we want to ignore.
 604			 */
 605			if ((~mask << (ACPI_MUL_8(sizeof(mask)) -
 606				       ACPI_MUL_8(obj_desc->common_field.
 607						  access_byte_width))) != 0) {
 608				/*
 609				 * Read the current contents of the byte/word/dword containing
 610				 * the field, and merge with the new field value.
 611				 */
 612				status =
 613				    acpi_ex_field_datum_io(obj_desc,
 614							   field_datum_byte_offset,
 615							   &current_value,
 616							   ACPI_READ);
 617				if (ACPI_FAILURE(status)) {
 618					return_ACPI_STATUS(status);
 619				}
 620
 621				merged_value |= (current_value & ~mask);
 622			}
 623			break;
 624
 625		case AML_FIELD_UPDATE_WRITE_AS_ONES:
 626
 627			/* Set positions outside the field to all ones */
 628
 629			merged_value |= ~mask;
 630			break;
 631
 632		case AML_FIELD_UPDATE_WRITE_AS_ZEROS:
 633
 634			/* Set positions outside the field to all zeros */
 635
 636			merged_value &= mask;
 637			break;
 638
 639		default:
 640
 641			ACPI_ERROR((AE_INFO,
 642				    "Unknown UpdateRule value: 0x%X",
 643				    (obj_desc->common_field.
 644				     field_flags &
 645				     AML_FIELD_UPDATE_RULE_MASK)));
 646			return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
 647		}
 648	}
 649
 650	ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 651			  "Mask %8.8X%8.8X, DatumOffset %X, Width %X, Value %8.8X%8.8X, MergedValue %8.8X%8.8X\n",
 652			  ACPI_FORMAT_UINT64(mask),
 653			  field_datum_byte_offset,
 654			  obj_desc->common_field.access_byte_width,
 655			  ACPI_FORMAT_UINT64(field_value),
 656			  ACPI_FORMAT_UINT64(merged_value)));
 657
 658	/* Write the merged value */
 659
 660	status = acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset,
 661					&merged_value, ACPI_WRITE);
 662
 663	return_ACPI_STATUS(status);
 664}
 665
 666/*******************************************************************************
 667 *
 668 * FUNCTION:    acpi_ex_extract_from_field
 669 *
 670 * PARAMETERS:  obj_desc            - Field to be read
 671 *              buffer              - Where to store the field data
 672 *              buffer_length       - Length of Buffer
 673 *
 674 * RETURN:      Status
 675 *
 676 * DESCRIPTION: Retrieve the current value of the given field
 677 *
 678 ******************************************************************************/
 679
 680acpi_status
 681acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
 682			   void *buffer, u32 buffer_length)
 683{
 684	acpi_status status;
 685	u64 raw_datum;
 686	u64 merged_datum;
 687	u32 field_offset = 0;
 688	u32 buffer_offset = 0;
 689	u32 buffer_tail_bits;
 690	u32 datum_count;
 691	u32 field_datum_count;
 692	u32 access_bit_width;
 693	u32 i;
 694
 695	ACPI_FUNCTION_TRACE(ex_extract_from_field);
 696
 697	/* Validate target buffer and clear it */
 698
 699	if (buffer_length <
 700	    ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length)) {
 701		ACPI_ERROR((AE_INFO,
 702			    "Field size %u (bits) is too large for buffer (%u)",
 703			    obj_desc->common_field.bit_length, buffer_length));
 704
 705		return_ACPI_STATUS(AE_BUFFER_OVERFLOW);
 706	}
 707
 708	ACPI_MEMSET(buffer, 0, buffer_length);
 709	access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
 710
 711	/* Handle the simple case here */
 712
 713	if ((obj_desc->common_field.start_field_bit_offset == 0) &&
 714	    (obj_desc->common_field.bit_length == access_bit_width)) {
 715		if (buffer_length >= sizeof(u64)) {
 716			status =
 717			    acpi_ex_field_datum_io(obj_desc, 0, buffer,
 718						   ACPI_READ);
 719		} else {
 720			/* Use raw_datum (u64) to handle buffers < 64 bits */
 721
 722			status =
 723			    acpi_ex_field_datum_io(obj_desc, 0, &raw_datum,
 724						   ACPI_READ);
 725			ACPI_MEMCPY(buffer, &raw_datum, buffer_length);
 726		}
 727
 728		return_ACPI_STATUS(status);
 729	}
 730
 731/* TBD: Move to common setup code */
 732
 733	/* Field algorithm is limited to sizeof(u64), truncate if needed */
 734
 735	if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
 736		obj_desc->common_field.access_byte_width = sizeof(u64);
 737		access_bit_width = sizeof(u64) * 8;
 738	}
 739
 740	/* Compute the number of datums (access width data items) */
 741
 742	datum_count =
 743	    ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
 744			     access_bit_width);
 745
 746	field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
 747					     obj_desc->common_field.
 748					     start_field_bit_offset,
 749					     access_bit_width);
 750
 751	/* Priming read from the field */
 752
 753	status =
 754	    acpi_ex_field_datum_io(obj_desc, field_offset, &raw_datum,
 755				   ACPI_READ);
 756	if (ACPI_FAILURE(status)) {
 757		return_ACPI_STATUS(status);
 758	}
 759	merged_datum =
 760	    raw_datum >> obj_desc->common_field.start_field_bit_offset;
 761
 762	/* Read the rest of the field */
 763
 764	for (i = 1; i < field_datum_count; i++) {
 765
 766		/* Get next input datum from the field */
 767
 768		field_offset += obj_desc->common_field.access_byte_width;
 769		status = acpi_ex_field_datum_io(obj_desc, field_offset,
 770						&raw_datum, ACPI_READ);
 771		if (ACPI_FAILURE(status)) {
 772			return_ACPI_STATUS(status);
 773		}
 774
 775		/*
 776		 * Merge with previous datum if necessary.
 777		 *
 778		 * Note: Before the shift, check if the shift value will be larger than
 779		 * the integer size. If so, there is no need to perform the operation.
 780		 * This avoids the differences in behavior between different compilers
 781		 * concerning shift values larger than the target data width.
 782		 */
 783		if (access_bit_width -
 784		    obj_desc->common_field.start_field_bit_offset <
 785		    ACPI_INTEGER_BIT_SIZE) {
 786			merged_datum |=
 787			    raw_datum << (access_bit_width -
 788					  obj_desc->common_field.
 789					  start_field_bit_offset);
 790		}
 791
 792		if (i == datum_count) {
 793			break;
 794		}
 795
 796		/* Write merged datum to target buffer */
 797
 798		ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
 799			    ACPI_MIN(obj_desc->common_field.access_byte_width,
 800				     buffer_length - buffer_offset));
 801
 802		buffer_offset += obj_desc->common_field.access_byte_width;
 803		merged_datum =
 804		    raw_datum >> obj_desc->common_field.start_field_bit_offset;
 805	}
 806
 807	/* Mask off any extra bits in the last datum */
 808
 809	buffer_tail_bits = obj_desc->common_field.bit_length % access_bit_width;
 810	if (buffer_tail_bits) {
 811		merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
 812	}
 813
 814	/* Write the last datum to the buffer */
 815
 816	ACPI_MEMCPY(((char *)buffer) + buffer_offset, &merged_datum,
 817		    ACPI_MIN(obj_desc->common_field.access_byte_width,
 818			     buffer_length - buffer_offset));
 819
 820	return_ACPI_STATUS(AE_OK);
 821}
 822
 823/*******************************************************************************
 824 *
 825 * FUNCTION:    acpi_ex_insert_into_field
 826 *
 827 * PARAMETERS:  obj_desc            - Field to be written
 828 *              buffer              - Data to be written
 829 *              buffer_length       - Length of Buffer
 830 *
 831 * RETURN:      Status
 832 *
 833 * DESCRIPTION: Store the Buffer contents into the given field
 834 *
 835 ******************************************************************************/
 836
 837acpi_status
 838acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
 839			  void *buffer, u32 buffer_length)
 840{
 841	void *new_buffer;
 842	acpi_status status;
 843	u64 mask;
 844	u64 width_mask;
 845	u64 merged_datum;
 846	u64 raw_datum = 0;
 847	u32 field_offset = 0;
 848	u32 buffer_offset = 0;
 849	u32 buffer_tail_bits;
 850	u32 datum_count;
 851	u32 field_datum_count;
 852	u32 access_bit_width;
 853	u32 required_length;
 854	u32 i;
 855
 856	ACPI_FUNCTION_TRACE(ex_insert_into_field);
 857
 858	/* Validate input buffer */
 859
 860	new_buffer = NULL;
 861	required_length =
 862	    ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length);
 863	/*
 864	 * We must have a buffer that is at least as long as the field
 865	 * we are writing to. This is because individual fields are
 866	 * indivisible and partial writes are not supported -- as per
 867	 * the ACPI specification.
 868	 */
 869	if (buffer_length < required_length) {
 870
 871		/* We need to create a new buffer */
 872
 873		new_buffer = ACPI_ALLOCATE_ZEROED(required_length);
 874		if (!new_buffer) {
 875			return_ACPI_STATUS(AE_NO_MEMORY);
 876		}
 877
 878		/*
 879		 * Copy the original data to the new buffer, starting
 880		 * at Byte zero. All unused (upper) bytes of the
 881		 * buffer will be 0.
 882		 */
 883		ACPI_MEMCPY((char *)new_buffer, (char *)buffer, buffer_length);
 884		buffer = new_buffer;
 885		buffer_length = required_length;
 886	}
 887
 888/* TBD: Move to common setup code */
 889
 890	/* Algo is limited to sizeof(u64), so cut the access_byte_width */
 891	if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
 892		obj_desc->common_field.access_byte_width = sizeof(u64);
 893	}
 894
 895	access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
 896
 897	/*
 898	 * Create the bitmasks used for bit insertion.
 899	 * Note: This if/else is used to bypass compiler differences with the
 900	 * shift operator
 901	 */
 902	if (access_bit_width == ACPI_INTEGER_BIT_SIZE) {
 903		width_mask = ACPI_UINT64_MAX;
 904	} else {
 905		width_mask = ACPI_MASK_BITS_ABOVE(access_bit_width);
 906	}
 907
 908	mask = width_mask &
 909	    ACPI_MASK_BITS_BELOW(obj_desc->common_field.start_field_bit_offset);
 910
 911	/* Compute the number of datums (access width data items) */
 912
 913	datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
 914				       access_bit_width);
 915
 916	field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
 917					     obj_desc->common_field.
 918					     start_field_bit_offset,
 919					     access_bit_width);
 920
 921	/* Get initial Datum from the input buffer */
 922
 923	ACPI_MEMCPY(&raw_datum, buffer,
 924		    ACPI_MIN(obj_desc->common_field.access_byte_width,
 925			     buffer_length - buffer_offset));
 926
 927	merged_datum =
 928	    raw_datum << obj_desc->common_field.start_field_bit_offset;
 929
 930	/* Write the entire field */
 931
 932	for (i = 1; i < field_datum_count; i++) {
 933
 934		/* Write merged datum to the target field */
 935
 936		merged_datum &= mask;
 937		status = acpi_ex_write_with_update_rule(obj_desc, mask,
 938							merged_datum,
 939							field_offset);
 940		if (ACPI_FAILURE(status)) {
 941			goto exit;
 942		}
 943
 944		field_offset += obj_desc->common_field.access_byte_width;
 945
 946		/*
 947		 * Start new output datum by merging with previous input datum
 948		 * if necessary.
 949		 *
 950		 * Note: Before the shift, check if the shift value will be larger than
 951		 * the integer size. If so, there is no need to perform the operation.
 952		 * This avoids the differences in behavior between different compilers
 953		 * concerning shift values larger than the target data width.
 954		 */
 955		if ((access_bit_width -
 956		     obj_desc->common_field.start_field_bit_offset) <
 957		    ACPI_INTEGER_BIT_SIZE) {
 958			merged_datum =
 959			    raw_datum >> (access_bit_width -
 960					  obj_desc->common_field.
 961					  start_field_bit_offset);
 962		} else {
 963			merged_datum = 0;
 964		}
 965
 966		mask = width_mask;
 967
 968		if (i == datum_count) {
 969			break;
 970		}
 971
 972		/* Get the next input datum from the buffer */
 973
 974		buffer_offset += obj_desc->common_field.access_byte_width;
 975		ACPI_MEMCPY(&raw_datum, ((char *)buffer) + buffer_offset,
 976			    ACPI_MIN(obj_desc->common_field.access_byte_width,
 977				     buffer_length - buffer_offset));
 978
 979		merged_datum |=
 980		    raw_datum << obj_desc->common_field.start_field_bit_offset;
 981	}
 982
 983	/* Mask off any extra bits in the last datum */
 984
 985	buffer_tail_bits = (obj_desc->common_field.bit_length +
 986			    obj_desc->common_field.start_field_bit_offset) %
 987	    access_bit_width;
 988	if (buffer_tail_bits) {
 989		mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
 990	}
 991
 992	/* Write the last datum to the field */
 993
 994	merged_datum &= mask;
 995	status = acpi_ex_write_with_update_rule(obj_desc,
 996						mask, merged_datum,
 997						field_offset);
 998
 999exit:
1000	/* Free temporary buffer if we used one */
1001
1002	if (new_buffer) {
1003		ACPI_FREE(new_buffer);
1004	}
1005	return_ACPI_STATUS(status);
1006}