1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /******************************************************************************
3  *
4  * Module Name: exfldio - Aml Field I/O
5  *
6  * Copyright (C) 2000 - 2023, Intel Corp.
7  *
8  *****************************************************************************/
9 
10 #include <acpi/acpi.h>
11 #include "accommon.h"
12 #include "acinterp.h"
13 #include "amlcode.h"
14 #include "acevents.h"
15 #include "acdispat.h"
16 
17 #define _COMPONENT          ACPI_EXECUTER
18 ACPI_MODULE_NAME("exfldio")
19 
20 /* Local prototypes */
21 static acpi_status
22 acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
23 		       u32 field_datum_byte_offset, u64 *value, u32 read_write);
24 
25 static u8
26 acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value);
27 
28 static acpi_status
29 acpi_ex_setup_region(union acpi_operand_object *obj_desc,
30 		     u32 field_datum_byte_offset);
31 
32 /*******************************************************************************
33  *
34  * FUNCTION:    acpi_ex_setup_region
35  *
36  * PARAMETERS:  obj_desc                - Field to be read or written
37  *              field_datum_byte_offset - Byte offset of this datum within the
38  *                                        parent field
39  *
40  * RETURN:      Status
41  *
42  * DESCRIPTION: Common processing for acpi_ex_extract_from_field and
43  *              acpi_ex_insert_into_field. Initialize the Region if necessary and
44  *              validate the request.
45  *
46  ******************************************************************************/
47 
48 static acpi_status
acpi_ex_setup_region(union acpi_operand_object * obj_desc,u32 field_datum_byte_offset)49 acpi_ex_setup_region(union acpi_operand_object *obj_desc,
50 		     u32 field_datum_byte_offset)
51 {
52 	acpi_status status = AE_OK;
53 	union acpi_operand_object *rgn_desc;
54 	u8 space_id;
55 
56 	ACPI_FUNCTION_TRACE_U32(ex_setup_region, field_datum_byte_offset);
57 
58 	rgn_desc = obj_desc->common_field.region_obj;
59 
60 	/* We must have a valid region */
61 
62 	if (rgn_desc->common.type != ACPI_TYPE_REGION) {
63 		ACPI_ERROR((AE_INFO, "Needed Region, found type 0x%X (%s)",
64 			    rgn_desc->common.type,
65 			    acpi_ut_get_object_type_name(rgn_desc)));
66 
67 		return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
68 	}
69 
70 	space_id = rgn_desc->region.space_id;
71 
72 	/* Validate the Space ID */
73 
74 	if (!acpi_is_valid_space_id(space_id)) {
75 		ACPI_ERROR((AE_INFO,
76 			    "Invalid/unknown Address Space ID: 0x%2.2X",
77 			    space_id));
78 		return_ACPI_STATUS(AE_AML_INVALID_SPACE_ID);
79 	}
80 
81 	/*
82 	 * If the Region Address and Length have not been previously evaluated,
83 	 * evaluate them now and save the results.
84 	 */
85 	if (!(rgn_desc->common.flags & AOPOBJ_DATA_VALID)) {
86 		status = acpi_ds_get_region_arguments(rgn_desc);
87 		if (ACPI_FAILURE(status)) {
88 			return_ACPI_STATUS(status);
89 		}
90 	}
91 
92 	/*
93 	 * Exit now for SMBus, GSBus or IPMI address space, it has a non-linear
94 	 * address space and the request cannot be directly validated
95 	 */
96 	if (space_id == ACPI_ADR_SPACE_SMBUS ||
97 	    space_id == ACPI_ADR_SPACE_GSBUS ||
98 	    space_id == ACPI_ADR_SPACE_IPMI) {
99 
100 		/* SMBus or IPMI has a non-linear address space */
101 
102 		return_ACPI_STATUS(AE_OK);
103 	}
104 #ifdef ACPI_UNDER_DEVELOPMENT
105 	/*
106 	 * If the Field access is any_acc, we can now compute the optimal
107 	 * access (because we know the length of the parent region)
108 	 */
109 	if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
110 		if (ACPI_FAILURE(status)) {
111 			return_ACPI_STATUS(status);
112 		}
113 	}
114 #endif
115 
116 	/*
117 	 * Validate the request. The entire request from the byte offset for a
118 	 * length of one field datum (access width) must fit within the region.
119 	 * (Region length is specified in bytes)
120 	 */
121 	if (rgn_desc->region.length <
122 	    (obj_desc->common_field.base_byte_offset + field_datum_byte_offset +
123 	     obj_desc->common_field.access_byte_width)) {
124 		if (acpi_gbl_enable_interpreter_slack) {
125 			/*
126 			 * Slack mode only:  We will go ahead and allow access to this
127 			 * field if it is within the region length rounded up to the next
128 			 * access width boundary. acpi_size cast for 64-bit compile.
129 			 */
130 			if (ACPI_ROUND_UP(rgn_desc->region.length,
131 					  obj_desc->common_field.
132 					  access_byte_width) >=
133 			    ((acpi_size)obj_desc->common_field.
134 			     base_byte_offset +
135 			     obj_desc->common_field.access_byte_width +
136 			     field_datum_byte_offset)) {
137 				return_ACPI_STATUS(AE_OK);
138 			}
139 		}
140 
141 		if (rgn_desc->region.length <
142 		    obj_desc->common_field.access_byte_width) {
143 			/*
144 			 * This is the case where the access_type (acc_word, etc.) is wider
145 			 * than the region itself. For example, a region of length one
146 			 * byte, and a field with Dword access specified.
147 			 */
148 			ACPI_ERROR((AE_INFO,
149 				    "Field [%4.4s] access width (%u bytes) "
150 				    "too large for region [%4.4s] (length %u)",
151 				    acpi_ut_get_node_name(obj_desc->
152 							  common_field.node),
153 				    obj_desc->common_field.access_byte_width,
154 				    acpi_ut_get_node_name(rgn_desc->region.
155 							  node),
156 				    rgn_desc->region.length));
157 		}
158 
159 		/*
160 		 * Offset rounded up to next multiple of field width
161 		 * exceeds region length, indicate an error
162 		 */
163 		ACPI_ERROR((AE_INFO,
164 			    "Field [%4.4s] Base+Offset+Width %u+%u+%u "
165 			    "is beyond end of region [%4.4s] (length %u)",
166 			    acpi_ut_get_node_name(obj_desc->common_field.node),
167 			    obj_desc->common_field.base_byte_offset,
168 			    field_datum_byte_offset,
169 			    obj_desc->common_field.access_byte_width,
170 			    acpi_ut_get_node_name(rgn_desc->region.node),
171 			    rgn_desc->region.length));
172 
173 		return_ACPI_STATUS(AE_AML_REGION_LIMIT);
174 	}
175 
176 	return_ACPI_STATUS(AE_OK);
177 }
178 
179 /*******************************************************************************
180  *
181  * FUNCTION:    acpi_ex_access_region
182  *
183  * PARAMETERS:  obj_desc                - Field to be read
184  *              field_datum_byte_offset - Byte offset of this datum within the
185  *                                        parent field
186  *              value                   - Where to store value (must at least
187  *                                        64 bits)
188  *              function                - Read or Write flag plus other region-
189  *                                        dependent flags
190  *
191  * RETURN:      Status
192  *
193  * DESCRIPTION: Read or Write a single field datum to an Operation Region.
194  *
195  ******************************************************************************/
196 
197 acpi_status
acpi_ex_access_region(union acpi_operand_object * obj_desc,u32 field_datum_byte_offset,u64 * value,u32 function)198 acpi_ex_access_region(union acpi_operand_object *obj_desc,
199 		      u32 field_datum_byte_offset, u64 *value, u32 function)
200 {
201 	acpi_status status;
202 	union acpi_operand_object *rgn_desc;
203 	u32 region_offset;
204 
205 	ACPI_FUNCTION_TRACE(ex_access_region);
206 
207 	/*
208 	 * Ensure that the region operands are fully evaluated and verify
209 	 * the validity of the request
210 	 */
211 	status = acpi_ex_setup_region(obj_desc, field_datum_byte_offset);
212 	if (ACPI_FAILURE(status)) {
213 		return_ACPI_STATUS(status);
214 	}
215 
216 	/*
217 	 * The physical address of this field datum is:
218 	 *
219 	 * 1) The base of the region, plus
220 	 * 2) The base offset of the field, plus
221 	 * 3) The current offset into the field
222 	 */
223 	rgn_desc = obj_desc->common_field.region_obj;
224 	region_offset =
225 	    obj_desc->common_field.base_byte_offset + field_datum_byte_offset;
226 
227 	if ((function & ACPI_IO_MASK) == ACPI_READ) {
228 		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[READ]"));
229 	} else {
230 		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, "[WRITE]"));
231 	}
232 
233 	ACPI_DEBUG_PRINT_RAW((ACPI_DB_BFIELD,
234 			      " Region [%s:%X], Width %X, ByteBase %X, Offset %X at %8.8X%8.8X\n",
235 			      acpi_ut_get_region_name(rgn_desc->region.
236 						      space_id),
237 			      rgn_desc->region.space_id,
238 			      obj_desc->common_field.access_byte_width,
239 			      obj_desc->common_field.base_byte_offset,
240 			      field_datum_byte_offset,
241 			      ACPI_FORMAT_UINT64(rgn_desc->region.address +
242 						 region_offset)));
243 
244 	/* Invoke the appropriate address_space/op_region handler */
245 
246 	status = acpi_ev_address_space_dispatch(rgn_desc, obj_desc,
247 						function, region_offset,
248 						ACPI_MUL_8(obj_desc->
249 							   common_field.
250 							   access_byte_width),
251 						value);
252 
253 	if (ACPI_FAILURE(status)) {
254 		if (status == AE_NOT_IMPLEMENTED) {
255 			ACPI_ERROR((AE_INFO,
256 				    "Region %s (ID=%u) not implemented",
257 				    acpi_ut_get_region_name(rgn_desc->region.
258 							    space_id),
259 				    rgn_desc->region.space_id));
260 		} else if (status == AE_NOT_EXIST) {
261 			ACPI_ERROR((AE_INFO,
262 				    "Region %s (ID=%u) has no handler",
263 				    acpi_ut_get_region_name(rgn_desc->region.
264 							    space_id),
265 				    rgn_desc->region.space_id));
266 		}
267 	}
268 
269 	return_ACPI_STATUS(status);
270 }
271 
272 /*******************************************************************************
273  *
274  * FUNCTION:    acpi_ex_register_overflow
275  *
276  * PARAMETERS:  obj_desc                - Register(Field) to be written
277  *              value                   - Value to be stored
278  *
279  * RETURN:      TRUE if value overflows the field, FALSE otherwise
280  *
281  * DESCRIPTION: Check if a value is out of range of the field being written.
282  *              Used to check if the values written to Index and Bank registers
283  *              are out of range. Normally, the value is simply truncated
284  *              to fit the field, but this case is most likely a serious
285  *              coding error in the ASL.
286  *
287  ******************************************************************************/
288 
289 static u8
acpi_ex_register_overflow(union acpi_operand_object * obj_desc,u64 value)290 acpi_ex_register_overflow(union acpi_operand_object *obj_desc, u64 value)
291 {
292 
293 	if (obj_desc->common_field.bit_length >= ACPI_INTEGER_BIT_SIZE) {
294 		/*
295 		 * The field is large enough to hold the maximum integer, so we can
296 		 * never overflow it.
297 		 */
298 		return (FALSE);
299 	}
300 
301 	if (value >= ((u64) 1 << obj_desc->common_field.bit_length)) {
302 		/*
303 		 * The Value is larger than the maximum value that can fit into
304 		 * the register.
305 		 */
306 		ACPI_ERROR((AE_INFO,
307 			    "Index value 0x%8.8X%8.8X overflows field width 0x%X",
308 			    ACPI_FORMAT_UINT64(value),
309 			    obj_desc->common_field.bit_length));
310 
311 		return (TRUE);
312 	}
313 
314 	/* The Value will fit into the field with no truncation */
315 
316 	return (FALSE);
317 }
318 
319 /*******************************************************************************
320  *
321  * FUNCTION:    acpi_ex_field_datum_io
322  *
323  * PARAMETERS:  obj_desc                - Field to be read
324  *              field_datum_byte_offset - Byte offset of this datum within the
325  *                                        parent field
326  *              value                   - Where to store value (must be 64 bits)
327  *              read_write              - Read or Write flag
328  *
329  * RETURN:      Status
330  *
331  * DESCRIPTION: Read or Write a single datum of a field. The field_type is
332  *              demultiplexed here to handle the different types of fields
333  *              (buffer_field, region_field, index_field, bank_field)
334  *
335  ******************************************************************************/
336 
337 static acpi_status
acpi_ex_field_datum_io(union acpi_operand_object * obj_desc,u32 field_datum_byte_offset,u64 * value,u32 read_write)338 acpi_ex_field_datum_io(union acpi_operand_object *obj_desc,
339 		       u32 field_datum_byte_offset, u64 *value, u32 read_write)
340 {
341 	acpi_status status;
342 	u64 local_value;
343 
344 	ACPI_FUNCTION_TRACE_U32(ex_field_datum_io, field_datum_byte_offset);
345 
346 	if (read_write == ACPI_READ) {
347 		if (!value) {
348 			local_value = 0;
349 
350 			/* To support reads without saving return value */
351 			value = &local_value;
352 		}
353 
354 		/* Clear the entire return buffer first, [Very Important!] */
355 
356 		*value = 0;
357 	}
358 
359 	/*
360 	 * The four types of fields are:
361 	 *
362 	 * buffer_field - Read/write from/to a Buffer
363 	 * region_field - Read/write from/to a Operation Region.
364 	 * bank_field  - Write to a Bank Register, then read/write from/to an
365 	 *               operation_region
366 	 * index_field - Write to an Index Register, then read/write from/to a
367 	 *               Data Register
368 	 */
369 	switch (obj_desc->common.type) {
370 	case ACPI_TYPE_BUFFER_FIELD:
371 		/*
372 		 * If the buffer_field arguments have not been previously evaluated,
373 		 * evaluate them now and save the results.
374 		 */
375 		if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
376 			status = acpi_ds_get_buffer_field_arguments(obj_desc);
377 			if (ACPI_FAILURE(status)) {
378 				return_ACPI_STATUS(status);
379 			}
380 		}
381 
382 		if (read_write == ACPI_READ) {
383 			/*
384 			 * Copy the data from the source buffer.
385 			 * Length is the field width in bytes.
386 			 */
387 			memcpy(value,
388 			       (obj_desc->buffer_field.buffer_obj)->buffer.
389 			       pointer +
390 			       obj_desc->buffer_field.base_byte_offset +
391 			       field_datum_byte_offset,
392 			       obj_desc->common_field.access_byte_width);
393 		} else {
394 			/*
395 			 * Copy the data to the target buffer.
396 			 * Length is the field width in bytes.
397 			 */
398 			memcpy((obj_desc->buffer_field.buffer_obj)->buffer.
399 			       pointer +
400 			       obj_desc->buffer_field.base_byte_offset +
401 			       field_datum_byte_offset, value,
402 			       obj_desc->common_field.access_byte_width);
403 		}
404 
405 		status = AE_OK;
406 		break;
407 
408 	case ACPI_TYPE_LOCAL_BANK_FIELD:
409 		/*
410 		 * Ensure that the bank_value is not beyond the capacity of
411 		 * the register
412 		 */
413 		if (acpi_ex_register_overflow(obj_desc->bank_field.bank_obj,
414 					      (u64) obj_desc->bank_field.
415 					      value)) {
416 			return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
417 		}
418 
419 		/*
420 		 * For bank_fields, we must write the bank_value to the bank_register
421 		 * (itself a region_field) before we can access the data.
422 		 */
423 		status =
424 		    acpi_ex_insert_into_field(obj_desc->bank_field.bank_obj,
425 					      &obj_desc->bank_field.value,
426 					      sizeof(obj_desc->bank_field.
427 						     value));
428 		if (ACPI_FAILURE(status)) {
429 			return_ACPI_STATUS(status);
430 		}
431 
432 		/*
433 		 * Now that the Bank has been selected, fall through to the
434 		 * region_field case and write the datum to the Operation Region
435 		 */
436 
437 		ACPI_FALLTHROUGH;
438 
439 	case ACPI_TYPE_LOCAL_REGION_FIELD:
440 		/*
441 		 * For simple region_fields, we just directly access the owning
442 		 * Operation Region.
443 		 */
444 		status =
445 		    acpi_ex_access_region(obj_desc, field_datum_byte_offset,
446 					  value, read_write);
447 		break;
448 
449 	case ACPI_TYPE_LOCAL_INDEX_FIELD:
450 		/*
451 		 * Ensure that the index_value is not beyond the capacity of
452 		 * the register
453 		 */
454 		if (acpi_ex_register_overflow(obj_desc->index_field.index_obj,
455 					      (u64) obj_desc->index_field.
456 					      value)) {
457 			return_ACPI_STATUS(AE_AML_REGISTER_LIMIT);
458 		}
459 
460 		/* Write the index value to the index_register (itself a region_field) */
461 
462 		field_datum_byte_offset += obj_desc->index_field.value;
463 
464 		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
465 				  "Write to Index Register: Value %8.8X\n",
466 				  field_datum_byte_offset));
467 
468 		status =
469 		    acpi_ex_insert_into_field(obj_desc->index_field.index_obj,
470 					      &field_datum_byte_offset,
471 					      sizeof(field_datum_byte_offset));
472 		if (ACPI_FAILURE(status)) {
473 			return_ACPI_STATUS(status);
474 		}
475 
476 		if (read_write == ACPI_READ) {
477 
478 			/* Read the datum from the data_register */
479 
480 			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
481 					  "Read from Data Register\n"));
482 
483 			status =
484 			    acpi_ex_extract_from_field(obj_desc->index_field.
485 						       data_obj, value,
486 						       sizeof(u64));
487 		} else {
488 			/* Write the datum to the data_register */
489 
490 			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
491 					  "Write to Data Register: Value %8.8X%8.8X\n",
492 					  ACPI_FORMAT_UINT64(*value)));
493 
494 			status =
495 			    acpi_ex_insert_into_field(obj_desc->index_field.
496 						      data_obj, value,
497 						      sizeof(u64));
498 		}
499 		break;
500 
501 	default:
502 
503 		ACPI_ERROR((AE_INFO, "Wrong object type in field I/O %u",
504 			    obj_desc->common.type));
505 		status = AE_AML_INTERNAL;
506 		break;
507 	}
508 
509 	if (ACPI_SUCCESS(status)) {
510 		if (read_write == ACPI_READ) {
511 			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
512 					  "Value Read %8.8X%8.8X, Width %u\n",
513 					  ACPI_FORMAT_UINT64(*value),
514 					  obj_desc->common_field.
515 					  access_byte_width));
516 		} else {
517 			ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
518 					  "Value Written %8.8X%8.8X, Width %u\n",
519 					  ACPI_FORMAT_UINT64(*value),
520 					  obj_desc->common_field.
521 					  access_byte_width));
522 		}
523 	}
524 
525 	return_ACPI_STATUS(status);
526 }
527 
528 /*******************************************************************************
529  *
530  * FUNCTION:    acpi_ex_write_with_update_rule
531  *
532  * PARAMETERS:  obj_desc                - Field to be written
533  *              mask                    - bitmask within field datum
534  *              field_value             - Value to write
535  *              field_datum_byte_offset - Offset of datum within field
536  *
537  * RETURN:      Status
538  *
539  * DESCRIPTION: Apply the field update rule to a field write
540  *
541  ******************************************************************************/
542 
543 acpi_status
acpi_ex_write_with_update_rule(union acpi_operand_object * obj_desc,u64 mask,u64 field_value,u32 field_datum_byte_offset)544 acpi_ex_write_with_update_rule(union acpi_operand_object *obj_desc,
545 			       u64 mask,
546 			       u64 field_value, u32 field_datum_byte_offset)
547 {
548 	acpi_status status = AE_OK;
549 	u64 merged_value;
550 	u64 current_value;
551 
552 	ACPI_FUNCTION_TRACE_U32(ex_write_with_update_rule, mask);
553 
554 	/* Start with the new bits  */
555 
556 	merged_value = field_value;
557 
558 	/* If the mask is all ones, we don't need to worry about the update rule */
559 
560 	if (mask != ACPI_UINT64_MAX) {
561 
562 		/* Decode the update rule */
563 
564 		switch (obj_desc->common_field.
565 			field_flags & AML_FIELD_UPDATE_RULE_MASK) {
566 		case AML_FIELD_UPDATE_PRESERVE:
567 			/*
568 			 * Check if update rule needs to be applied (not if mask is all
569 			 * ones)  The left shift drops the bits we want to ignore.
570 			 */
571 			if ((~mask << (ACPI_MUL_8(sizeof(mask)) -
572 				       ACPI_MUL_8(obj_desc->common_field.
573 						  access_byte_width))) != 0) {
574 				/*
575 				 * Read the current contents of the byte/word/dword containing
576 				 * the field, and merge with the new field value.
577 				 */
578 				status =
579 				    acpi_ex_field_datum_io(obj_desc,
580 							   field_datum_byte_offset,
581 							   &current_value,
582 							   ACPI_READ);
583 				if (ACPI_FAILURE(status)) {
584 					return_ACPI_STATUS(status);
585 				}
586 
587 				merged_value |= (current_value & ~mask);
588 			}
589 			break;
590 
591 		case AML_FIELD_UPDATE_WRITE_AS_ONES:
592 
593 			/* Set positions outside the field to all ones */
594 
595 			merged_value |= ~mask;
596 			break;
597 
598 		case AML_FIELD_UPDATE_WRITE_AS_ZEROS:
599 
600 			/* Set positions outside the field to all zeros */
601 
602 			merged_value &= mask;
603 			break;
604 
605 		default:
606 
607 			ACPI_ERROR((AE_INFO,
608 				    "Unknown UpdateRule value: 0x%X",
609 				    (obj_desc->common_field.field_flags &
610 				     AML_FIELD_UPDATE_RULE_MASK)));
611 			return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
612 		}
613 	}
614 
615 	ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
616 			  "Mask %8.8X%8.8X, DatumOffset %X, Width %X, "
617 			  "Value %8.8X%8.8X, MergedValue %8.8X%8.8X\n",
618 			  ACPI_FORMAT_UINT64(mask),
619 			  field_datum_byte_offset,
620 			  obj_desc->common_field.access_byte_width,
621 			  ACPI_FORMAT_UINT64(field_value),
622 			  ACPI_FORMAT_UINT64(merged_value)));
623 
624 	/* Write the merged value */
625 
626 	status =
627 	    acpi_ex_field_datum_io(obj_desc, field_datum_byte_offset,
628 				   &merged_value, ACPI_WRITE);
629 
630 	return_ACPI_STATUS(status);
631 }
632 
633 /*******************************************************************************
634  *
635  * FUNCTION:    acpi_ex_extract_from_field
636  *
637  * PARAMETERS:  obj_desc            - Field to be read
638  *              buffer              - Where to store the field data
639  *              buffer_length       - Length of Buffer
640  *
641  * RETURN:      Status
642  *
643  * DESCRIPTION: Retrieve the current value of the given field
644  *
645  ******************************************************************************/
646 
647 acpi_status
acpi_ex_extract_from_field(union acpi_operand_object * obj_desc,void * buffer,u32 buffer_length)648 acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
649 			   void *buffer, u32 buffer_length)
650 {
651 	acpi_status status;
652 	u64 raw_datum;
653 	u64 merged_datum;
654 	u32 field_offset = 0;
655 	u32 buffer_offset = 0;
656 	u32 buffer_tail_bits;
657 	u32 datum_count;
658 	u32 field_datum_count;
659 	u32 access_bit_width;
660 	u32 i;
661 
662 	ACPI_FUNCTION_TRACE(ex_extract_from_field);
663 
664 	/* Validate target buffer and clear it */
665 
666 	if (buffer_length <
667 	    ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length)) {
668 		ACPI_ERROR((AE_INFO,
669 			    "Field size %u (bits) is too large for buffer (%u)",
670 			    obj_desc->common_field.bit_length, buffer_length));
671 
672 		return_ACPI_STATUS(AE_BUFFER_OVERFLOW);
673 	}
674 
675 	memset(buffer, 0, buffer_length);
676 	access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
677 
678 	/* Handle the simple case here */
679 
680 	if ((obj_desc->common_field.start_field_bit_offset == 0) &&
681 	    (obj_desc->common_field.bit_length == access_bit_width)) {
682 		if (buffer_length >= sizeof(u64)) {
683 			status =
684 			    acpi_ex_field_datum_io(obj_desc, 0, buffer,
685 						   ACPI_READ);
686 		} else {
687 			/* Use raw_datum (u64) to handle buffers < 64 bits */
688 
689 			status =
690 			    acpi_ex_field_datum_io(obj_desc, 0, &raw_datum,
691 						   ACPI_READ);
692 			memcpy(buffer, &raw_datum, buffer_length);
693 		}
694 
695 		return_ACPI_STATUS(status);
696 	}
697 
698 /* TBD: Move to common setup code */
699 
700 	/* Field algorithm is limited to sizeof(u64), truncate if needed */
701 
702 	if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
703 		obj_desc->common_field.access_byte_width = sizeof(u64);
704 		access_bit_width = sizeof(u64) * 8;
705 	}
706 
707 	/* Compute the number of datums (access width data items) */
708 
709 	datum_count =
710 	    ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
711 			     access_bit_width);
712 
713 	field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
714 					     obj_desc->common_field.
715 					     start_field_bit_offset,
716 					     access_bit_width);
717 
718 	/* Priming read from the field */
719 
720 	status =
721 	    acpi_ex_field_datum_io(obj_desc, field_offset, &raw_datum,
722 				   ACPI_READ);
723 	if (ACPI_FAILURE(status)) {
724 		return_ACPI_STATUS(status);
725 	}
726 	merged_datum =
727 	    raw_datum >> obj_desc->common_field.start_field_bit_offset;
728 
729 	/* Read the rest of the field */
730 
731 	for (i = 1; i < field_datum_count; i++) {
732 
733 		/* Get next input datum from the field */
734 
735 		field_offset += obj_desc->common_field.access_byte_width;
736 		status =
737 		    acpi_ex_field_datum_io(obj_desc, field_offset, &raw_datum,
738 					   ACPI_READ);
739 		if (ACPI_FAILURE(status)) {
740 			return_ACPI_STATUS(status);
741 		}
742 
743 		/*
744 		 * Merge with previous datum if necessary.
745 		 *
746 		 * Note: Before the shift, check if the shift value will be larger than
747 		 * the integer size. If so, there is no need to perform the operation.
748 		 * This avoids the differences in behavior between different compilers
749 		 * concerning shift values larger than the target data width.
750 		 */
751 		if (access_bit_width -
752 		    obj_desc->common_field.start_field_bit_offset <
753 		    ACPI_INTEGER_BIT_SIZE) {
754 			merged_datum |=
755 			    raw_datum << (access_bit_width -
756 					  obj_desc->common_field.
757 					  start_field_bit_offset);
758 		}
759 
760 		if (i == datum_count) {
761 			break;
762 		}
763 
764 		/* Write merged datum to target buffer */
765 
766 		memcpy(((char *)buffer) + buffer_offset, &merged_datum,
767 		       ACPI_MIN(obj_desc->common_field.access_byte_width,
768 				buffer_length - buffer_offset));
769 
770 		buffer_offset += obj_desc->common_field.access_byte_width;
771 		merged_datum =
772 		    raw_datum >> obj_desc->common_field.start_field_bit_offset;
773 	}
774 
775 	/* Mask off any extra bits in the last datum */
776 
777 	buffer_tail_bits = obj_desc->common_field.bit_length % access_bit_width;
778 	if (buffer_tail_bits) {
779 		merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
780 	}
781 
782 	/* Write the last datum to the buffer */
783 
784 	memcpy(((char *)buffer) + buffer_offset, &merged_datum,
785 	       ACPI_MIN(obj_desc->common_field.access_byte_width,
786 			buffer_length - buffer_offset));
787 
788 	return_ACPI_STATUS(AE_OK);
789 }
790 
791 /*******************************************************************************
792  *
793  * FUNCTION:    acpi_ex_insert_into_field
794  *
795  * PARAMETERS:  obj_desc            - Field to be written
796  *              buffer              - Data to be written
797  *              buffer_length       - Length of Buffer
798  *
799  * RETURN:      Status
800  *
801  * DESCRIPTION: Store the Buffer contents into the given field
802  *
803  ******************************************************************************/
804 
805 acpi_status
acpi_ex_insert_into_field(union acpi_operand_object * obj_desc,void * buffer,u32 buffer_length)806 acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
807 			  void *buffer, u32 buffer_length)
808 {
809 	void *new_buffer;
810 	acpi_status status;
811 	u64 mask;
812 	u64 width_mask;
813 	u64 merged_datum;
814 	u64 raw_datum = 0;
815 	u32 field_offset = 0;
816 	u32 buffer_offset = 0;
817 	u32 buffer_tail_bits;
818 	u32 datum_count;
819 	u32 field_datum_count;
820 	u32 access_bit_width;
821 	u32 required_length;
822 	u32 i;
823 
824 	ACPI_FUNCTION_TRACE(ex_insert_into_field);
825 
826 	/* Validate input buffer */
827 
828 	new_buffer = NULL;
829 	required_length =
830 	    ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.bit_length);
831 
832 	/*
833 	 * We must have a buffer that is at least as long as the field
834 	 * we are writing to. This is because individual fields are
835 	 * indivisible and partial writes are not supported -- as per
836 	 * the ACPI specification.
837 	 */
838 	if (buffer_length < required_length) {
839 
840 		/* We need to create a new buffer */
841 
842 		new_buffer = ACPI_ALLOCATE_ZEROED(required_length);
843 		if (!new_buffer) {
844 			return_ACPI_STATUS(AE_NO_MEMORY);
845 		}
846 
847 		/*
848 		 * Copy the original data to the new buffer, starting
849 		 * at Byte zero. All unused (upper) bytes of the
850 		 * buffer will be 0.
851 		 */
852 		memcpy((char *)new_buffer, (char *)buffer, buffer_length);
853 		buffer = new_buffer;
854 		buffer_length = required_length;
855 	}
856 
857 /* TBD: Move to common setup code */
858 
859 	/* Algo is limited to sizeof(u64), so cut the access_byte_width */
860 	if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
861 		obj_desc->common_field.access_byte_width = sizeof(u64);
862 	}
863 
864 	access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
865 
866 	/* Create the bitmasks used for bit insertion */
867 
868 	width_mask = ACPI_MASK_BITS_ABOVE_64(access_bit_width);
869 	mask = width_mask &
870 	    ACPI_MASK_BITS_BELOW(obj_desc->common_field.start_field_bit_offset);
871 
872 	/* Compute the number of datums (access width data items) */
873 
874 	datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
875 				       access_bit_width);
876 
877 	field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
878 					     obj_desc->common_field.
879 					     start_field_bit_offset,
880 					     access_bit_width);
881 
882 	/* Get initial Datum from the input buffer */
883 
884 	memcpy(&raw_datum, buffer,
885 	       ACPI_MIN(obj_desc->common_field.access_byte_width,
886 			buffer_length - buffer_offset));
887 
888 	merged_datum =
889 	    raw_datum << obj_desc->common_field.start_field_bit_offset;
890 
891 	/* Write the entire field */
892 
893 	for (i = 1; i < field_datum_count; i++) {
894 
895 		/* Write merged datum to the target field */
896 
897 		merged_datum &= mask;
898 		status =
899 		    acpi_ex_write_with_update_rule(obj_desc, mask, merged_datum,
900 						   field_offset);
901 		if (ACPI_FAILURE(status)) {
902 			goto exit;
903 		}
904 
905 		field_offset += obj_desc->common_field.access_byte_width;
906 
907 		/*
908 		 * Start new output datum by merging with previous input datum
909 		 * if necessary.
910 		 *
911 		 * Note: Before the shift, check if the shift value will be larger than
912 		 * the integer size. If so, there is no need to perform the operation.
913 		 * This avoids the differences in behavior between different compilers
914 		 * concerning shift values larger than the target data width.
915 		 */
916 		if ((access_bit_width -
917 		     obj_desc->common_field.start_field_bit_offset) <
918 		    ACPI_INTEGER_BIT_SIZE) {
919 			merged_datum =
920 			    raw_datum >> (access_bit_width -
921 					  obj_desc->common_field.
922 					  start_field_bit_offset);
923 		} else {
924 			merged_datum = 0;
925 		}
926 
927 		mask = width_mask;
928 
929 		if (i == datum_count) {
930 			break;
931 		}
932 
933 		/* Get the next input datum from the buffer */
934 
935 		buffer_offset += obj_desc->common_field.access_byte_width;
936 		memcpy(&raw_datum, ((char *)buffer) + buffer_offset,
937 		       ACPI_MIN(obj_desc->common_field.access_byte_width,
938 				buffer_length - buffer_offset));
939 
940 		merged_datum |=
941 		    raw_datum << obj_desc->common_field.start_field_bit_offset;
942 	}
943 
944 	/* Mask off any extra bits in the last datum */
945 
946 	buffer_tail_bits = (obj_desc->common_field.bit_length +
947 			    obj_desc->common_field.start_field_bit_offset) %
948 	    access_bit_width;
949 	if (buffer_tail_bits) {
950 		mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
951 	}
952 
953 	/* Write the last datum to the field */
954 
955 	merged_datum &= mask;
956 	status =
957 	    acpi_ex_write_with_update_rule(obj_desc, mask, merged_datum,
958 					   field_offset);
959 
960 exit:
961 	/* Free temporary buffer if we used one */
962 
963 	if (new_buffer) {
964 		ACPI_FREE(new_buffer);
965 	}
966 	return_ACPI_STATUS(status);
967 }
968