File: main.c

package info (click to toggle)
linux 4.19.37-3
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 962,264 kB
  • sloc: ansic: 16,757,120; asm: 271,404; makefile: 38,285; sh: 33,529; perl: 27,681; python: 21,031; cpp: 5,063; yacc: 4,648; lex: 2,585; awk: 1,385; ruby: 25; sed: 5
file content (1283 lines) | stat: -rw-r--r-- 31,231 bytes parent folder | download | duplicates (10)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
// SPDX-License-Identifier: GPL-2.0
/*
 * main.c - Multi purpose firmware loading support
 *
 * Copyright (c) 2003 Manuel Estrada Sainz
 *
 * Please see Documentation/firmware_class/ for more information.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/capability.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <linux/highmem.h>
#include <linux/firmware.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/async.h>
#include <linux/pm.h>
#include <linux/suspend.h>
#include <linux/syscore_ops.h>
#include <linux/reboot.h>
#include <linux/security.h>

#include <generated/utsrelease.h>

#include "../base.h"
#include "firmware.h"
#include "fallback.h"

MODULE_AUTHOR("Manuel Estrada Sainz");
MODULE_DESCRIPTION("Multi purpose firmware loading support");
MODULE_LICENSE("GPL");

struct firmware_cache {
	/* firmware_buf instance will be added into the below list */
	spinlock_t lock;
	struct list_head head;
	int state;

#ifdef CONFIG_PM_SLEEP
	/*
	 * Names of firmware images which have been cached successfully
	 * will be added into the below list so that device uncache
	 * helper can trace which firmware images have been cached
	 * before.
	 */
	spinlock_t name_lock;
	struct list_head fw_names;

	struct delayed_work work;

	struct notifier_block   pm_notify;
#endif
};

struct fw_cache_entry {
	struct list_head list;
	const char *name;
};

struct fw_name_devm {
	unsigned long magic;
	const char *name;
};

static inline struct fw_priv *to_fw_priv(struct kref *ref)
{
	return container_of(ref, struct fw_priv, ref);
}

#define	FW_LOADER_NO_CACHE	0
#define	FW_LOADER_START_CACHE	1

/* fw_lock could be moved to 'struct fw_sysfs' but since it is just
 * guarding for corner cases a global lock should be OK */
DEFINE_MUTEX(fw_lock);

static struct firmware_cache fw_cache;

/* Builtin firmware support */

#ifdef CONFIG_FW_LOADER

extern struct builtin_fw __start_builtin_fw[];
extern struct builtin_fw __end_builtin_fw[];

static void fw_copy_to_prealloc_buf(struct firmware *fw,
				    void *buf, size_t size)
{
	if (!buf || size < fw->size)
		return;
	memcpy(buf, fw->data, fw->size);
}

static bool fw_get_builtin_firmware(struct firmware *fw, const char *name,
				    void *buf, size_t size)
{
	struct builtin_fw *b_fw;

	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
		if (strcmp(name, b_fw->name) == 0) {
			fw->size = b_fw->size;
			fw->data = b_fw->data;
			fw_copy_to_prealloc_buf(fw, buf, size);

			return true;
		}
	}

	return false;
}

static bool fw_is_builtin_firmware(const struct firmware *fw)
{
	struct builtin_fw *b_fw;

	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
		if (fw->data == b_fw->data)
			return true;

	return false;
}

#else /* Module case - no builtin firmware support */

static inline bool fw_get_builtin_firmware(struct firmware *fw,
					   const char *name, void *buf,
					   size_t size)
{
	return false;
}

static inline bool fw_is_builtin_firmware(const struct firmware *fw)
{
	return false;
}
#endif

static void fw_state_init(struct fw_priv *fw_priv)
{
	struct fw_state *fw_st = &fw_priv->fw_st;

	init_completion(&fw_st->completion);
	fw_st->status = FW_STATUS_UNKNOWN;
}

static inline int fw_state_wait(struct fw_priv *fw_priv)
{
	return __fw_state_wait_common(fw_priv, MAX_SCHEDULE_TIMEOUT);
}

static int fw_cache_piggyback_on_request(const char *name);

static struct fw_priv *__allocate_fw_priv(const char *fw_name,
					  struct firmware_cache *fwc,
					  void *dbuf, size_t size)
{
	struct fw_priv *fw_priv;

	fw_priv = kzalloc(sizeof(*fw_priv), GFP_ATOMIC);
	if (!fw_priv)
		return NULL;

	fw_priv->fw_name = kstrdup_const(fw_name, GFP_ATOMIC);
	if (!fw_priv->fw_name) {
		kfree(fw_priv);
		return NULL;
	}

	kref_init(&fw_priv->ref);
	fw_priv->fwc = fwc;
	fw_priv->data = dbuf;
	fw_priv->allocated_size = size;
	fw_state_init(fw_priv);
#ifdef CONFIG_FW_LOADER_USER_HELPER
	INIT_LIST_HEAD(&fw_priv->pending_list);
#endif

	pr_debug("%s: fw-%s fw_priv=%p\n", __func__, fw_name, fw_priv);

	return fw_priv;
}

static struct fw_priv *__lookup_fw_priv(const char *fw_name)
{
	struct fw_priv *tmp;
	struct firmware_cache *fwc = &fw_cache;

	list_for_each_entry(tmp, &fwc->head, list)
		if (!strcmp(tmp->fw_name, fw_name))
			return tmp;
	return NULL;
}

/* Returns 1 for batching firmware requests with the same name */
static int alloc_lookup_fw_priv(const char *fw_name,
				struct firmware_cache *fwc,
				struct fw_priv **fw_priv, void *dbuf,
				size_t size, enum fw_opt opt_flags)
{
	struct fw_priv *tmp;

	spin_lock(&fwc->lock);
	if (!(opt_flags & FW_OPT_NOCACHE)) {
		tmp = __lookup_fw_priv(fw_name);
		if (tmp) {
			kref_get(&tmp->ref);
			spin_unlock(&fwc->lock);
			*fw_priv = tmp;
			pr_debug("batched request - sharing the same struct fw_priv and lookup for multiple requests\n");
			return 1;
		}
	}

	tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size);
	if (tmp) {
		INIT_LIST_HEAD(&tmp->list);
		if (!(opt_flags & FW_OPT_NOCACHE))
			list_add(&tmp->list, &fwc->head);
	}
	spin_unlock(&fwc->lock);

	*fw_priv = tmp;

	return tmp ? 0 : -ENOMEM;
}

static void __free_fw_priv(struct kref *ref)
	__releases(&fwc->lock)
{
	struct fw_priv *fw_priv = to_fw_priv(ref);
	struct firmware_cache *fwc = fw_priv->fwc;

	pr_debug("%s: fw-%s fw_priv=%p data=%p size=%u\n",
		 __func__, fw_priv->fw_name, fw_priv, fw_priv->data,
		 (unsigned int)fw_priv->size);

	list_del(&fw_priv->list);
	spin_unlock(&fwc->lock);

#ifdef CONFIG_FW_LOADER_USER_HELPER
	if (fw_priv->is_paged_buf) {
		int i;
		vunmap(fw_priv->data);
		for (i = 0; i < fw_priv->nr_pages; i++)
			__free_page(fw_priv->pages[i]);
		vfree(fw_priv->pages);
	} else
#endif
	if (!fw_priv->allocated_size)
		vfree(fw_priv->data);
	kfree_const(fw_priv->fw_name);
	kfree(fw_priv);
}

static void free_fw_priv(struct fw_priv *fw_priv)
{
	struct firmware_cache *fwc = fw_priv->fwc;
	spin_lock(&fwc->lock);
	if (!kref_put(&fw_priv->ref, __free_fw_priv))
		spin_unlock(&fwc->lock);
}

/* direct firmware loading support */
static char fw_path_para[256];
static const char * const fw_path[] = {
	fw_path_para,
	"/lib/firmware/updates/" UTS_RELEASE,
	"/lib/firmware/updates",
	"/lib/firmware/" UTS_RELEASE,
	"/lib/firmware"
};

/*
 * Typical usage is that passing 'firmware_class.path=$CUSTOMIZED_PATH'
 * from kernel command line because firmware_class is generally built in
 * kernel instead of module.
 */
module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644);
MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path");

static int
fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv)
{
	loff_t size;
	int i, len;
	int rc = -ENOENT;
	char *path;
	enum kernel_read_file_id id = READING_FIRMWARE;
	size_t msize = INT_MAX;

	/* Already populated data member means we're loading into a buffer */
	if (fw_priv->data) {
		id = READING_FIRMWARE_PREALLOC_BUFFER;
		msize = fw_priv->allocated_size;
	}

	path = __getname();
	if (!path)
		return -ENOMEM;

	for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
		/* skip the unset customized path */
		if (!fw_path[i][0])
			continue;

		len = snprintf(path, PATH_MAX, "%s/%s",
			       fw_path[i], fw_priv->fw_name);
		if (len >= PATH_MAX) {
			rc = -ENAMETOOLONG;
			break;
		}

		fw_priv->size = 0;
		rc = kernel_read_file_from_path(path, &fw_priv->data, &size,
						msize, id);
		if (rc) {
			dev_dbg(device, "loading %s failed with error %d\n",
				path, rc);
			continue;
		}
		dev_info(device, "firmware: direct-loading firmware %s\n",
			 fw_priv->fw_name);
		fw_priv->size = size;
		fw_state_done(fw_priv);
		break;
	}
	__putname(path);

	if (rc) {
		dev_err(device, "firmware: failed to load %s (%d)\n",
			fw_priv->fw_name, rc);
		if (rc == -ENOENT)
			pr_err_once("See https://wiki.debian.org/Firmware for information about missing firmware\n");
	}

	return rc;
}

/* firmware holds the ownership of pages */
static void firmware_free_data(const struct firmware *fw)
{
	/* Loaded directly? */
	if (!fw->priv) {
		vfree(fw->data);
		return;
	}
	free_fw_priv(fw->priv);
}

/* store the pages buffer info firmware from buf */
static void fw_set_page_data(struct fw_priv *fw_priv, struct firmware *fw)
{
	fw->priv = fw_priv;
#ifdef CONFIG_FW_LOADER_USER_HELPER
	fw->pages = fw_priv->pages;
#endif
	fw->size = fw_priv->size;
	fw->data = fw_priv->data;

	pr_debug("%s: fw-%s fw_priv=%p data=%p size=%u\n",
		 __func__, fw_priv->fw_name, fw_priv, fw_priv->data,
		 (unsigned int)fw_priv->size);
}

#ifdef CONFIG_PM_SLEEP
static void fw_name_devm_release(struct device *dev, void *res)
{
	struct fw_name_devm *fwn = res;

	if (fwn->magic == (unsigned long)&fw_cache)
		pr_debug("%s: fw_name-%s devm-%p released\n",
				__func__, fwn->name, res);
	kfree_const(fwn->name);
}

static int fw_devm_match(struct device *dev, void *res,
		void *match_data)
{
	struct fw_name_devm *fwn = res;

	return (fwn->magic == (unsigned long)&fw_cache) &&
		!strcmp(fwn->name, match_data);
}

static struct fw_name_devm *fw_find_devm_name(struct device *dev,
		const char *name)
{
	struct fw_name_devm *fwn;

	fwn = devres_find(dev, fw_name_devm_release,
			  fw_devm_match, (void *)name);
	return fwn;
}

static bool fw_cache_is_setup(struct device *dev, const char *name)
{
	struct fw_name_devm *fwn;

	fwn = fw_find_devm_name(dev, name);
	if (fwn)
		return true;

	return false;
}

/* add firmware name into devres list */
static int fw_add_devm_name(struct device *dev, const char *name)
{
	struct fw_name_devm *fwn;

	if (fw_cache_is_setup(dev, name))
		return 0;

	fwn = devres_alloc(fw_name_devm_release, sizeof(struct fw_name_devm),
			   GFP_KERNEL);
	if (!fwn)
		return -ENOMEM;
	fwn->name = kstrdup_const(name, GFP_KERNEL);
	if (!fwn->name) {
		devres_free(fwn);
		return -ENOMEM;
	}

	fwn->magic = (unsigned long)&fw_cache;
	devres_add(dev, fwn);

	return 0;
}
#else
static bool fw_cache_is_setup(struct device *dev, const char *name)
{
	return false;
}

static int fw_add_devm_name(struct device *dev, const char *name)
{
	return 0;
}
#endif

int assign_fw(struct firmware *fw, struct device *device,
	      enum fw_opt opt_flags)
{
	struct fw_priv *fw_priv = fw->priv;
	int ret;

	mutex_lock(&fw_lock);
	if (!fw_priv->size || fw_state_is_aborted(fw_priv)) {
		mutex_unlock(&fw_lock);
		return -ENOENT;
	}

	/*
	 * add firmware name into devres list so that we can auto cache
	 * and uncache firmware for device.
	 *
	 * device may has been deleted already, but the problem
	 * should be fixed in devres or driver core.
	 */
	/* don't cache firmware handled without uevent */
	if (device && (opt_flags & FW_OPT_UEVENT) &&
	    !(opt_flags & FW_OPT_NOCACHE)) {
		ret = fw_add_devm_name(device, fw_priv->fw_name);
		if (ret) {
			mutex_unlock(&fw_lock);
			return ret;
		}
	}

	/*
	 * After caching firmware image is started, let it piggyback
	 * on request firmware.
	 */
	if (!(opt_flags & FW_OPT_NOCACHE) &&
	    fw_priv->fwc->state == FW_LOADER_START_CACHE) {
		if (fw_cache_piggyback_on_request(fw_priv->fw_name))
			kref_get(&fw_priv->ref);
	}

	/* pass the pages buffer to driver at the last minute */
	fw_set_page_data(fw_priv, fw);
	mutex_unlock(&fw_lock);
	return 0;
}

/* prepare firmware and firmware_buf structs;
 * return 0 if a firmware is already assigned, 1 if need to load one,
 * or a negative error code
 */
static int
_request_firmware_prepare(struct firmware **firmware_p, const char *name,
			  struct device *device, void *dbuf, size_t size,
			  enum fw_opt opt_flags)
{
	struct firmware *firmware;
	struct fw_priv *fw_priv;
	int ret;

	*firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
	if (!firmware) {
		dev_err(device, "%s: kmalloc(struct firmware) failed\n",
			__func__);
		return -ENOMEM;
	}

	if (fw_get_builtin_firmware(firmware, name, dbuf, size)) {
		dev_dbg(device, "using built-in %s\n", name);
		return 0; /* assigned */
	}

	ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv, dbuf, size,
				  opt_flags);

	/*
	 * bind with 'priv' now to avoid warning in failure path
	 * of requesting firmware.
	 */
	firmware->priv = fw_priv;

	if (ret > 0) {
		ret = fw_state_wait(fw_priv);
		if (!ret) {
			fw_set_page_data(fw_priv, firmware);
			return 0; /* assigned */
		}
	}

	if (ret < 0)
		return ret;
	return 1; /* need to load */
}

/*
 * Batched requests need only one wake, we need to do this step last due to the
 * fallback mechanism. The buf is protected with kref_get(), and it won't be
 * released until the last user calls release_firmware().
 *
 * Failed batched requests are possible as well, in such cases we just share
 * the struct fw_priv and won't release it until all requests are woken
 * and have gone through this same path.
 */
static void fw_abort_batch_reqs(struct firmware *fw)
{
	struct fw_priv *fw_priv;

	/* Loaded directly? */
	if (!fw || !fw->priv)
		return;

	fw_priv = fw->priv;
	if (!fw_state_is_aborted(fw_priv))
		fw_state_aborted(fw_priv);
}

/* called from request_firmware() and request_firmware_work_func() */
static int
_request_firmware(const struct firmware **firmware_p, const char *name,
		  struct device *device, void *buf, size_t size,
		  enum fw_opt opt_flags)
{
	struct firmware *fw = NULL;
	int ret;

	if (!firmware_p)
		return -EINVAL;

	if (!name || name[0] == '\0') {
		ret = -EINVAL;
		goto out;
	}

	ret = _request_firmware_prepare(&fw, name, device, buf, size,
					opt_flags);
	if (ret <= 0) /* error or already assigned */
		goto out;

	ret = fw_get_filesystem_firmware(device, fw->priv);
	if (ret) {
		if (!(opt_flags & FW_OPT_NO_WARN))
			dev_warn(device,
				 "Direct firmware load for %s failed with error %d\n",
				 name, ret);
		ret = firmware_fallback_sysfs(fw, name, device, opt_flags, ret);
	} else
		ret = assign_fw(fw, device, opt_flags);

 out:
	if (ret < 0) {
		fw_abort_batch_reqs(fw);
		release_firmware(fw);
		fw = NULL;
	}

	*firmware_p = fw;
	return ret;
}

/**
 * request_firmware() - send firmware request and wait for it
 * @firmware_p: pointer to firmware image
 * @name: name of firmware file
 * @device: device for which firmware is being loaded
 *
 *      @firmware_p will be used to return a firmware image by the name
 *      of @name for device @device.
 *
 *      Should be called from user context where sleeping is allowed.
 *
 *      @name will be used as $FIRMWARE in the uevent environment and
 *      should be distinctive enough not to be confused with any other
 *      firmware image for this or any other device.
 *
 *	Caller must hold the reference count of @device.
 *
 *	The function can be called safely inside device's suspend and
 *	resume callback.
 **/
int
request_firmware(const struct firmware **firmware_p, const char *name,
		 struct device *device)
{
	int ret;

	/* Need to pin this module until return */
	__module_get(THIS_MODULE);
	ret = _request_firmware(firmware_p, name, device, NULL, 0,
				FW_OPT_UEVENT);
	module_put(THIS_MODULE);
	return ret;
}
EXPORT_SYMBOL(request_firmware);

/**
 * firmware_request_nowarn() - request for an optional fw module
 * @firmware: pointer to firmware image
 * @name: name of firmware file
 * @device: device for which firmware is being loaded
 *
 * This function is similar in behaviour to request_firmware(), except
 * it doesn't produce warning messages when the file is not found.
 * The sysfs fallback mechanism is enabled if direct filesystem lookup fails,
 * however, however failures to find the firmware file with it are still
 * suppressed. It is therefore up to the driver to check for the return value
 * of this call and to decide when to inform the users of errors.
 **/
int firmware_request_nowarn(const struct firmware **firmware, const char *name,
			    struct device *device)
{
	int ret;

	/* Need to pin this module until return */
	__module_get(THIS_MODULE);
	ret = _request_firmware(firmware, name, device, NULL, 0,
				FW_OPT_UEVENT | FW_OPT_NO_WARN);
	module_put(THIS_MODULE);
	return ret;
}
EXPORT_SYMBOL_GPL(firmware_request_nowarn);

/**
 * request_firmware_direct() - load firmware directly without usermode helper
 * @firmware_p: pointer to firmware image
 * @name: name of firmware file
 * @device: device for which firmware is being loaded
 *
 * This function works pretty much like request_firmware(), but this doesn't
 * fall back to usermode helper even if the firmware couldn't be loaded
 * directly from fs.  Hence it's useful for loading optional firmwares, which
 * aren't always present, without extra long timeouts of udev.
 **/
int request_firmware_direct(const struct firmware **firmware_p,
			    const char *name, struct device *device)
{
	int ret;

	__module_get(THIS_MODULE);
	ret = _request_firmware(firmware_p, name, device, NULL, 0,
				FW_OPT_UEVENT | FW_OPT_NO_WARN |
				FW_OPT_NOFALLBACK);
	module_put(THIS_MODULE);
	return ret;
}
EXPORT_SYMBOL_GPL(request_firmware_direct);

/**
 * firmware_request_cache() - cache firmware for suspend so resume can use it
 * @name: name of firmware file
 * @device: device for which firmware should be cached for
 *
 * There are some devices with an optimization that enables the device to not
 * require loading firmware on system reboot. This optimization may still
 * require the firmware present on resume from suspend. This routine can be
 * used to ensure the firmware is present on resume from suspend in these
 * situations. This helper is not compatible with drivers which use
 * request_firmware_into_buf() or request_firmware_nowait() with no uevent set.
 **/
int firmware_request_cache(struct device *device, const char *name)
{
	int ret;

	mutex_lock(&fw_lock);
	ret = fw_add_devm_name(device, name);
	mutex_unlock(&fw_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(firmware_request_cache);

/**
 * request_firmware_into_buf() - load firmware into a previously allocated buffer
 * @firmware_p: pointer to firmware image
 * @name: name of firmware file
 * @device: device for which firmware is being loaded and DMA region allocated
 * @buf: address of buffer to load firmware into
 * @size: size of buffer
 *
 * This function works pretty much like request_firmware(), but it doesn't
 * allocate a buffer to hold the firmware data. Instead, the firmware
 * is loaded directly into the buffer pointed to by @buf and the @firmware_p
 * data member is pointed at @buf.
 *
 * This function doesn't cache firmware either.
 */
int
request_firmware_into_buf(const struct firmware **firmware_p, const char *name,
			  struct device *device, void *buf, size_t size)
{
	int ret;

	if (fw_cache_is_setup(device, name))
		return -EOPNOTSUPP;

	__module_get(THIS_MODULE);
	ret = _request_firmware(firmware_p, name, device, buf, size,
				FW_OPT_UEVENT | FW_OPT_NOCACHE);
	module_put(THIS_MODULE);
	return ret;
}
EXPORT_SYMBOL(request_firmware_into_buf);

/**
 * release_firmware() - release the resource associated with a firmware image
 * @fw: firmware resource to release
 **/
void release_firmware(const struct firmware *fw)
{
	if (fw) {
		if (!fw_is_builtin_firmware(fw))
			firmware_free_data(fw);
		kfree(fw);
	}
}
EXPORT_SYMBOL(release_firmware);

/* Async support */
struct firmware_work {
	struct work_struct work;
	struct module *module;
	const char *name;
	struct device *device;
	void *context;
	void (*cont)(const struct firmware *fw, void *context);
	enum fw_opt opt_flags;
};

static void request_firmware_work_func(struct work_struct *work)
{
	struct firmware_work *fw_work;
	const struct firmware *fw;

	fw_work = container_of(work, struct firmware_work, work);

	_request_firmware(&fw, fw_work->name, fw_work->device, NULL, 0,
			  fw_work->opt_flags);
	fw_work->cont(fw, fw_work->context);
	put_device(fw_work->device); /* taken in request_firmware_nowait() */

	module_put(fw_work->module);
	kfree_const(fw_work->name);
	kfree(fw_work);
}

/**
 * request_firmware_nowait() - asynchronous version of request_firmware
 * @module: module requesting the firmware
 * @uevent: sends uevent to copy the firmware image if this flag
 *	is non-zero else the firmware copy must be done manually.
 * @name: name of firmware file
 * @device: device for which firmware is being loaded
 * @gfp: allocation flags
 * @context: will be passed over to @cont, and
 *	@fw may be %NULL if firmware request fails.
 * @cont: function will be called asynchronously when the firmware
 *	request is over.
 *
 *	Caller must hold the reference count of @device.
 *
 *	Asynchronous variant of request_firmware() for user contexts:
 *		- sleep for as small periods as possible since it may
 *		  increase kernel boot time of built-in device drivers
 *		  requesting firmware in their ->probe() methods, if
 *		  @gfp is GFP_KERNEL.
 *
 *		- can't sleep at all if @gfp is GFP_ATOMIC.
 **/
int
request_firmware_nowait(
	struct module *module, bool uevent,
	const char *name, struct device *device, gfp_t gfp, void *context,
	void (*cont)(const struct firmware *fw, void *context))
{
	struct firmware_work *fw_work;

	fw_work = kzalloc(sizeof(struct firmware_work), gfp);
	if (!fw_work)
		return -ENOMEM;

	fw_work->module = module;
	fw_work->name = kstrdup_const(name, gfp);
	if (!fw_work->name) {
		kfree(fw_work);
		return -ENOMEM;
	}
	fw_work->device = device;
	fw_work->context = context;
	fw_work->cont = cont;
	fw_work->opt_flags = FW_OPT_NOWAIT |
		(uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER);

	if (!uevent && fw_cache_is_setup(device, name)) {
		kfree_const(fw_work->name);
		kfree(fw_work);
		return -EOPNOTSUPP;
	}

	if (!try_module_get(module)) {
		kfree_const(fw_work->name);
		kfree(fw_work);
		return -EFAULT;
	}

	get_device(fw_work->device);
	INIT_WORK(&fw_work->work, request_firmware_work_func);
	schedule_work(&fw_work->work);
	return 0;
}
EXPORT_SYMBOL(request_firmware_nowait);

#ifdef CONFIG_PM_SLEEP
static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);

/**
 * cache_firmware() - cache one firmware image in kernel memory space
 * @fw_name: the firmware image name
 *
 * Cache firmware in kernel memory so that drivers can use it when
 * system isn't ready for them to request firmware image from userspace.
 * Once it returns successfully, driver can use request_firmware or its
 * nowait version to get the cached firmware without any interacting
 * with userspace
 *
 * Return 0 if the firmware image has been cached successfully
 * Return !0 otherwise
 *
 */
static int cache_firmware(const char *fw_name)
{
	int ret;
	const struct firmware *fw;

	pr_debug("%s: %s\n", __func__, fw_name);

	ret = request_firmware(&fw, fw_name, NULL);
	if (!ret)
		kfree(fw);

	pr_debug("%s: %s ret=%d\n", __func__, fw_name, ret);

	return ret;
}

static struct fw_priv *lookup_fw_priv(const char *fw_name)
{
	struct fw_priv *tmp;
	struct firmware_cache *fwc = &fw_cache;

	spin_lock(&fwc->lock);
	tmp = __lookup_fw_priv(fw_name);
	spin_unlock(&fwc->lock);

	return tmp;
}

/**
 * uncache_firmware() - remove one cached firmware image
 * @fw_name: the firmware image name
 *
 * Uncache one firmware image which has been cached successfully
 * before.
 *
 * Return 0 if the firmware cache has been removed successfully
 * Return !0 otherwise
 *
 */
static int uncache_firmware(const char *fw_name)
{
	struct fw_priv *fw_priv;
	struct firmware fw;

	pr_debug("%s: %s\n", __func__, fw_name);

	if (fw_get_builtin_firmware(&fw, fw_name, NULL, 0))
		return 0;

	fw_priv = lookup_fw_priv(fw_name);
	if (fw_priv) {
		free_fw_priv(fw_priv);
		return 0;
	}

	return -EINVAL;
}

static struct fw_cache_entry *alloc_fw_cache_entry(const char *name)
{
	struct fw_cache_entry *fce;

	fce = kzalloc(sizeof(*fce), GFP_ATOMIC);
	if (!fce)
		goto exit;

	fce->name = kstrdup_const(name, GFP_ATOMIC);
	if (!fce->name) {
		kfree(fce);
		fce = NULL;
		goto exit;
	}
exit:
	return fce;
}

static int __fw_entry_found(const char *name)
{
	struct firmware_cache *fwc = &fw_cache;
	struct fw_cache_entry *fce;

	list_for_each_entry(fce, &fwc->fw_names, list) {
		if (!strcmp(fce->name, name))
			return 1;
	}
	return 0;
}

static int fw_cache_piggyback_on_request(const char *name)
{
	struct firmware_cache *fwc = &fw_cache;
	struct fw_cache_entry *fce;
	int ret = 0;

	spin_lock(&fwc->name_lock);
	if (__fw_entry_found(name))
		goto found;

	fce = alloc_fw_cache_entry(name);
	if (fce) {
		ret = 1;
		list_add(&fce->list, &fwc->fw_names);
		pr_debug("%s: fw: %s\n", __func__, name);
	}
found:
	spin_unlock(&fwc->name_lock);
	return ret;
}

static void free_fw_cache_entry(struct fw_cache_entry *fce)
{
	kfree_const(fce->name);
	kfree(fce);
}

static void __async_dev_cache_fw_image(void *fw_entry,
				       async_cookie_t cookie)
{
	struct fw_cache_entry *fce = fw_entry;
	struct firmware_cache *fwc = &fw_cache;
	int ret;

	ret = cache_firmware(fce->name);
	if (ret) {
		spin_lock(&fwc->name_lock);
		list_del(&fce->list);
		spin_unlock(&fwc->name_lock);

		free_fw_cache_entry(fce);
	}
}

/* called with dev->devres_lock held */
static void dev_create_fw_entry(struct device *dev, void *res,
				void *data)
{
	struct fw_name_devm *fwn = res;
	const char *fw_name = fwn->name;
	struct list_head *head = data;
	struct fw_cache_entry *fce;

	fce = alloc_fw_cache_entry(fw_name);
	if (fce)
		list_add(&fce->list, head);
}

static int devm_name_match(struct device *dev, void *res,
			   void *match_data)
{
	struct fw_name_devm *fwn = res;
	return (fwn->magic == (unsigned long)match_data);
}

static void dev_cache_fw_image(struct device *dev, void *data)
{
	LIST_HEAD(todo);
	struct fw_cache_entry *fce;
	struct fw_cache_entry *fce_next;
	struct firmware_cache *fwc = &fw_cache;

	devres_for_each_res(dev, fw_name_devm_release,
			    devm_name_match, &fw_cache,
			    dev_create_fw_entry, &todo);

	list_for_each_entry_safe(fce, fce_next, &todo, list) {
		list_del(&fce->list);

		spin_lock(&fwc->name_lock);
		/* only one cache entry for one firmware */
		if (!__fw_entry_found(fce->name)) {
			list_add(&fce->list, &fwc->fw_names);
		} else {
			free_fw_cache_entry(fce);
			fce = NULL;
		}
		spin_unlock(&fwc->name_lock);

		if (fce)
			async_schedule_domain(__async_dev_cache_fw_image,
					      (void *)fce,
					      &fw_cache_domain);
	}
}

static void __device_uncache_fw_images(void)
{
	struct firmware_cache *fwc = &fw_cache;
	struct fw_cache_entry *fce;

	spin_lock(&fwc->name_lock);
	while (!list_empty(&fwc->fw_names)) {
		fce = list_entry(fwc->fw_names.next,
				struct fw_cache_entry, list);
		list_del(&fce->list);
		spin_unlock(&fwc->name_lock);

		uncache_firmware(fce->name);
		free_fw_cache_entry(fce);

		spin_lock(&fwc->name_lock);
	}
	spin_unlock(&fwc->name_lock);
}

/**
 * device_cache_fw_images() - cache devices' firmware
 *
 * If one device called request_firmware or its nowait version
 * successfully before, the firmware names are recored into the
 * device's devres link list, so device_cache_fw_images can call
 * cache_firmware() to cache these firmwares for the device,
 * then the device driver can load its firmwares easily at
 * time when system is not ready to complete loading firmware.
 */
static void device_cache_fw_images(void)
{
	struct firmware_cache *fwc = &fw_cache;
	DEFINE_WAIT(wait);

	pr_debug("%s\n", __func__);

	/* cancel uncache work */
	cancel_delayed_work_sync(&fwc->work);

	fw_fallback_set_cache_timeout();

	mutex_lock(&fw_lock);
	fwc->state = FW_LOADER_START_CACHE;
	dpm_for_each_dev(NULL, dev_cache_fw_image);
	mutex_unlock(&fw_lock);

	/* wait for completion of caching firmware for all devices */
	async_synchronize_full_domain(&fw_cache_domain);

	fw_fallback_set_default_timeout();
}

/**
 * device_uncache_fw_images() - uncache devices' firmware
 *
 * uncache all firmwares which have been cached successfully
 * by device_uncache_fw_images earlier
 */
static void device_uncache_fw_images(void)
{
	pr_debug("%s\n", __func__);
	__device_uncache_fw_images();
}

static void device_uncache_fw_images_work(struct work_struct *work)
{
	device_uncache_fw_images();
}

/**
 * device_uncache_fw_images_delay() - uncache devices firmwares
 * @delay: number of milliseconds to delay uncache device firmwares
 *
 * uncache all devices's firmwares which has been cached successfully
 * by device_cache_fw_images after @delay milliseconds.
 */
static void device_uncache_fw_images_delay(unsigned long delay)
{
	queue_delayed_work(system_power_efficient_wq, &fw_cache.work,
			   msecs_to_jiffies(delay));
}

static int fw_pm_notify(struct notifier_block *notify_block,
			unsigned long mode, void *unused)
{
	switch (mode) {
	case PM_HIBERNATION_PREPARE:
	case PM_SUSPEND_PREPARE:
	case PM_RESTORE_PREPARE:
		/*
		 * kill pending fallback requests with a custom fallback
		 * to avoid stalling suspend.
		 */
		kill_pending_fw_fallback_reqs(true);
		device_cache_fw_images();
		break;

	case PM_POST_SUSPEND:
	case PM_POST_HIBERNATION:
	case PM_POST_RESTORE:
		/*
		 * In case that system sleep failed and syscore_suspend is
		 * not called.
		 */
		mutex_lock(&fw_lock);
		fw_cache.state = FW_LOADER_NO_CACHE;
		mutex_unlock(&fw_lock);

		device_uncache_fw_images_delay(10 * MSEC_PER_SEC);
		break;
	}

	return 0;
}

/* stop caching firmware once syscore_suspend is reached */
static int fw_suspend(void)
{
	fw_cache.state = FW_LOADER_NO_CACHE;
	return 0;
}

static struct syscore_ops fw_syscore_ops = {
	.suspend = fw_suspend,
};

static int __init register_fw_pm_ops(void)
{
	int ret;

	spin_lock_init(&fw_cache.name_lock);
	INIT_LIST_HEAD(&fw_cache.fw_names);

	INIT_DELAYED_WORK(&fw_cache.work,
			  device_uncache_fw_images_work);

	fw_cache.pm_notify.notifier_call = fw_pm_notify;
	ret = register_pm_notifier(&fw_cache.pm_notify);
	if (ret)
		return ret;

	register_syscore_ops(&fw_syscore_ops);

	return ret;
}

static inline void unregister_fw_pm_ops(void)
{
	unregister_syscore_ops(&fw_syscore_ops);
	unregister_pm_notifier(&fw_cache.pm_notify);
}
#else
static int fw_cache_piggyback_on_request(const char *name)
{
	return 0;
}
static inline int register_fw_pm_ops(void)
{
	return 0;
}
static inline void unregister_fw_pm_ops(void)
{
}
#endif

static void __init fw_cache_init(void)
{
	spin_lock_init(&fw_cache.lock);
	INIT_LIST_HEAD(&fw_cache.head);
	fw_cache.state = FW_LOADER_NO_CACHE;
}

static int fw_shutdown_notify(struct notifier_block *unused1,
			      unsigned long unused2, void *unused3)
{
	/*
	 * Kill all pending fallback requests to avoid both stalling shutdown,
	 * and avoid a deadlock with the usermode_lock.
	 */
	kill_pending_fw_fallback_reqs(false);

	return NOTIFY_DONE;
}

static struct notifier_block fw_shutdown_nb = {
	.notifier_call = fw_shutdown_notify,
};

static int __init firmware_class_init(void)
{
	int ret;

	/* No need to unfold these on exit */
	fw_cache_init();

	ret = register_fw_pm_ops();
	if (ret)
		return ret;

	ret = register_reboot_notifier(&fw_shutdown_nb);
	if (ret)
		goto out;

	return register_sysfs_loader();

out:
	unregister_fw_pm_ops();
	return ret;
}

static void __exit firmware_class_exit(void)
{
	unregister_fw_pm_ops();
	unregister_reboot_notifier(&fw_shutdown_nb);
	unregister_sysfs_loader();
}

fs_initcall(firmware_class_init);
module_exit(firmware_class_exit);