Free Electrons

Embedded Linux Experts

   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
/*
 * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
 * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
 * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
 *
 * This file is released under the GPLv2.
 */

#define pr_fmt(fmt) "PM: " fmt

#include <linux/export.h>
#include <linux/suspend.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/async.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pm.h>
#include <linux/nmi.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/freezer.h>
#include <linux/gfp.h>
#include <linux/syscore_ops.h>
#include <linux/ctype.h>
#include <linux/genhd.h>
#include <linux/ktime.h>
#include <trace/events/power.h>

#include "power.h"


static int nocompress;
static int noresume;
static int nohibernate;
static int resume_wait;
static unsigned int resume_delay;
static char resume_file[256] = CONFIG_PM_STD_PARTITION;
dev_t swsusp_resume_device;
sector_t swsusp_resume_block;
__visible int in_suspend __nosavedata;

enum {
	HIBERNATION_INVALID,
	HIBERNATION_PLATFORM,
	HIBERNATION_SHUTDOWN,
	HIBERNATION_REBOOT,
#ifdef CONFIG_SUSPEND
	HIBERNATION_SUSPEND,
#endif
	HIBERNATION_TEST_RESUME,
	/* keep last */
	__HIBERNATION_AFTER_LAST
};
#define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
#define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)

static int hibernation_mode = HIBERNATION_SHUTDOWN;

bool freezer_test_done;

static const struct platform_hibernation_ops *hibernation_ops;

bool hibernation_available(void)
{
	return (nohibernate == 0);
}

/**
 * hibernation_set_ops - Set the global hibernate operations.
 * @ops: Hibernation operations to use in subsequent hibernation transitions.
 */
void hibernation_set_ops(const struct platform_hibernation_ops *ops)
{
	if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
	    && ops->prepare && ops->finish && ops->enter && ops->pre_restore
	    && ops->restore_cleanup && ops->leave)) {
		WARN_ON(1);
		return;
	}
	lock_system_sleep();
	hibernation_ops = ops;
	if (ops)
		hibernation_mode = HIBERNATION_PLATFORM;
	else if (hibernation_mode == HIBERNATION_PLATFORM)
		hibernation_mode = HIBERNATION_SHUTDOWN;

	unlock_system_sleep();
}
EXPORT_SYMBOL_GPL(hibernation_set_ops);

static bool entering_platform_hibernation;

bool system_entering_hibernation(void)
{
	return entering_platform_hibernation;
}
EXPORT_SYMBOL(system_entering_hibernation);

#ifdef CONFIG_PM_DEBUG
static void hibernation_debug_sleep(void)
{
	pr_info("hibernation debug: Waiting for 5 seconds.\n");
	mdelay(5000);
}

static int hibernation_test(int level)
{
	if (pm_test_level == level) {
		hibernation_debug_sleep();
		return 1;
	}
	return 0;
}
#else /* !CONFIG_PM_DEBUG */
static int hibernation_test(int level) { return 0; }
#endif /* !CONFIG_PM_DEBUG */

/**
 * platform_begin - Call platform to start hibernation.
 * @platform_mode: Whether or not to use the platform driver.
 */
static int platform_begin(int platform_mode)
{
	return (platform_mode && hibernation_ops) ?
		hibernation_ops->begin() : 0;
}

/**
 * platform_end - Call platform to finish transition to the working state.
 * @platform_mode: Whether or not to use the platform driver.
 */
static void platform_end(int platform_mode)
{
	if (platform_mode && hibernation_ops)
		hibernation_ops->end();
}

/**
 * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 * @platform_mode: Whether or not to use the platform driver.
 *
 * Use the platform driver to prepare the system for creating a hibernate image,
 * if so configured, and return an error code if that fails.
 */

static int platform_pre_snapshot(int platform_mode)
{
	return (platform_mode && hibernation_ops) ?
		hibernation_ops->pre_snapshot() : 0;
}

/**
 * platform_leave - Call platform to prepare a transition to the working state.
 * @platform_mode: Whether or not to use the platform driver.
 *
 * Use the platform driver prepare to prepare the machine for switching to the
 * normal mode of operation.
 *
 * This routine is called on one CPU with interrupts disabled.
 */
static void platform_leave(int platform_mode)
{
	if (platform_mode && hibernation_ops)
		hibernation_ops->leave();
}

/**
 * platform_finish - Call platform to switch the system to the working state.
 * @platform_mode: Whether or not to use the platform driver.
 *
 * Use the platform driver to switch the machine to the normal mode of
 * operation.
 *
 * This routine must be called after platform_prepare().
 */
static void platform_finish(int platform_mode)
{
	if (platform_mode && hibernation_ops)
		hibernation_ops->finish();
}

/**
 * platform_pre_restore - Prepare for hibernate image restoration.
 * @platform_mode: Whether or not to use the platform driver.
 *
 * Use the platform driver to prepare the system for resume from a hibernation
 * image.
 *
 * If the restore fails after this function has been called,
 * platform_restore_cleanup() must be called.
 */
static int platform_pre_restore(int platform_mode)
{
	return (platform_mode && hibernation_ops) ?
		hibernation_ops->pre_restore() : 0;
}

/**
 * platform_restore_cleanup - Switch to the working state after failing restore.
 * @platform_mode: Whether or not to use the platform driver.
 *
 * Use the platform driver to switch the system to the normal mode of operation
 * after a failing restore.
 *
 * If platform_pre_restore() has been called before the failing restore, this
 * function must be called too, regardless of the result of
 * platform_pre_restore().
 */
static void platform_restore_cleanup(int platform_mode)
{
	if (platform_mode && hibernation_ops)
		hibernation_ops->restore_cleanup();
}

/**
 * platform_recover - Recover from a failure to suspend devices.
 * @platform_mode: Whether or not to use the platform driver.
 */
static void platform_recover(int platform_mode)
{
	if (platform_mode && hibernation_ops && hibernation_ops->recover)
		hibernation_ops->recover();
}

/**
 * swsusp_show_speed - Print time elapsed between two events during hibernation.
 * @start: Starting event.
 * @stop: Final event.
 * @nr_pages: Number of memory pages processed between @start and @stop.
 * @msg: Additional diagnostic message to print.
 */
void swsusp_show_speed(ktime_t start, ktime_t stop,
		      unsigned nr_pages, char *msg)
{
	ktime_t diff;
	u64 elapsed_centisecs64;
	unsigned int centisecs;
	unsigned int k;
	unsigned int kps;

	diff = ktime_sub(stop, start);
	elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
	centisecs = elapsed_centisecs64;
	if (centisecs == 0)
		centisecs = 1;	/* avoid div-by-zero */
	k = nr_pages * (PAGE_SIZE / 1024);
	kps = (k * 100) / centisecs;
	pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
		msg, k, centisecs / 100, centisecs % 100, kps / 1000,
		(kps % 1000) / 10);
}

/**
 * create_image - Create a hibernation image.
 * @platform_mode: Whether or not to use the platform driver.
 *
 * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 *
 * Control reappears in this routine after the subsequent restore.
 */
static int create_image(int platform_mode)
{
	int error;

	error = dpm_suspend_end(PMSG_FREEZE);
	if (error) {
		pr_err("Some devices failed to power down, aborting hibernation\n");
		return error;
	}

	error = platform_pre_snapshot(platform_mode);
	if (error || hibernation_test(TEST_PLATFORM))
		goto Platform_finish;

	error = disable_nonboot_cpus();
	if (error || hibernation_test(TEST_CPUS))
		goto Enable_cpus;

	local_irq_disable();

	error = syscore_suspend();
	if (error) {
		pr_err("Some system devices failed to power down, aborting hibernation\n");
		goto Enable_irqs;
	}

	if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
		goto Power_up;

	in_suspend = 1;
	save_processor_state();
	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
	error = swsusp_arch_suspend();
	/* Restore control flow magically appears here */
	restore_processor_state();
	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
	if (error)
		pr_err("Error %d creating hibernation image\n", error);

	if (!in_suspend) {
		events_check_enabled = false;
		clear_free_pages();
	}

	platform_leave(platform_mode);

 Power_up:
	syscore_resume();

 Enable_irqs:
	local_irq_enable();

 Enable_cpus:
	enable_nonboot_cpus();

 Platform_finish:
	platform_finish(platform_mode);

	dpm_resume_start(in_suspend ?
		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);

	return error;
}

/**
 * hibernation_snapshot - Quiesce devices and create a hibernation image.
 * @platform_mode: If set, use platform driver to prepare for the transition.
 *
 * This routine must be called with pm_mutex held.
 */
int hibernation_snapshot(int platform_mode)
{
	pm_message_t msg;
	int error;

	pm_suspend_clear_flags();
	error = platform_begin(platform_mode);
	if (error)
		goto Close;

	/* Preallocate image memory before shutting down devices. */
	error = hibernate_preallocate_memory();
	if (error)
		goto Close;

	error = freeze_kernel_threads();
	if (error)
		goto Cleanup;

	if (hibernation_test(TEST_FREEZER)) {

		/*
		 * Indicate to the caller that we are returning due to a
		 * successful freezer test.
		 */
		freezer_test_done = true;
		goto Thaw;
	}

	error = dpm_prepare(PMSG_FREEZE);
	if (error) {
		dpm_complete(PMSG_RECOVER);
		goto Thaw;
	}

	suspend_console();
	pm_restrict_gfp_mask();

	error = dpm_suspend(PMSG_FREEZE);

	if (error || hibernation_test(TEST_DEVICES))
		platform_recover(platform_mode);
	else
		error = create_image(platform_mode);

	/*
	 * In the case that we call create_image() above, the control
	 * returns here (1) after the image has been created or the
	 * image creation has failed and (2) after a successful restore.
	 */

	/* We may need to release the preallocated image pages here. */
	if (error || !in_suspend)
		swsusp_free();

	msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
	dpm_resume(msg);

	if (error || !in_suspend)
		pm_restore_gfp_mask();

	resume_console();
	dpm_complete(msg);

 Close:
	platform_end(platform_mode);
	return error;

 Thaw:
	thaw_kernel_threads();
 Cleanup:
	swsusp_free();
	goto Close;
}

int __weak hibernate_resume_nonboot_cpu_disable(void)
{
	return disable_nonboot_cpus();
}

/**
 * resume_target_kernel - Restore system state from a hibernation image.
 * @platform_mode: Whether or not to use the platform driver.
 *
 * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 * contents of highmem that have not been restored yet from the image and run
 * the low-level code that will restore the remaining contents of memory and
 * switch to the just restored target kernel.
 */
static int resume_target_kernel(bool platform_mode)
{
	int error;

	error = dpm_suspend_end(PMSG_QUIESCE);
	if (error) {
		pr_err("Some devices failed to power down, aborting resume\n");
		return error;
	}

	error = platform_pre_restore(platform_mode);
	if (error)
		goto Cleanup;

	error = hibernate_resume_nonboot_cpu_disable();
	if (error)
		goto Enable_cpus;

	local_irq_disable();

	error = syscore_suspend();
	if (error)
		goto Enable_irqs;

	save_processor_state();
	error = restore_highmem();
	if (!error) {
		error = swsusp_arch_resume();
		/*
		 * The code below is only ever reached in case of a failure.
		 * Otherwise, execution continues at the place where
		 * swsusp_arch_suspend() was called.
		 */
		BUG_ON(!error);
		/*
		 * This call to restore_highmem() reverts the changes made by
		 * the previous one.
		 */
		restore_highmem();
	}
	/*
	 * The only reason why swsusp_arch_resume() can fail is memory being
	 * very tight, so we have to free it as soon as we can to avoid
	 * subsequent failures.
	 */
	swsusp_free();
	restore_processor_state();
	touch_softlockup_watchdog();

	syscore_resume();

 Enable_irqs:
	local_irq_enable();

 Enable_cpus:
	enable_nonboot_cpus();

 Cleanup:
	platform_restore_cleanup(platform_mode);

	dpm_resume_start(PMSG_RECOVER);

	return error;
}

/**
 * hibernation_restore - Quiesce devices and restore from a hibernation image.
 * @platform_mode: If set, use platform driver to prepare for the transition.
 *
 * This routine must be called with pm_mutex held.  If it is successful, control
 * reappears in the restored target kernel in hibernation_snapshot().
 */
int hibernation_restore(int platform_mode)
{
	int error;

	pm_prepare_console();
	suspend_console();
	pm_restrict_gfp_mask();
	error = dpm_suspend_start(PMSG_QUIESCE);
	if (!error) {
		error = resume_target_kernel(platform_mode);
		/*
		 * The above should either succeed and jump to the new kernel,
		 * or return with an error. Otherwise things are just
		 * undefined, so let's be paranoid.
		 */
		BUG_ON(!error);
	}
	dpm_resume_end(PMSG_RECOVER);
	pm_restore_gfp_mask();
	resume_console();
	pm_restore_console();
	return error;
}

/**
 * hibernation_platform_enter - Power off the system using the platform driver.
 */
int hibernation_platform_enter(void)
{
	int error;

	if (!hibernation_ops)
		return -ENOSYS;

	/*
	 * We have cancelled the power transition by running
	 * hibernation_ops->finish() before saving the image, so we should let
	 * the firmware know that we're going to enter the sleep state after all
	 */
	error = hibernation_ops->begin();
	if (error)
		goto Close;

	entering_platform_hibernation = true;
	suspend_console();
	error = dpm_suspend_start(PMSG_HIBERNATE);
	if (error) {
		if (hibernation_ops->recover)
			hibernation_ops->recover();
		goto Resume_devices;
	}

	error = dpm_suspend_end(PMSG_HIBERNATE);
	if (error)
		goto Resume_devices;

	error = hibernation_ops->prepare();
	if (error)
		goto Platform_finish;

	error = disable_nonboot_cpus();
	if (error)
		goto Enable_cpus;

	local_irq_disable();
	syscore_suspend();
	if (pm_wakeup_pending()) {
		error = -EAGAIN;
		goto Power_up;
	}

	hibernation_ops->enter();
	/* We should never get here */
	while (1);

 Power_up:
	syscore_resume();
	local_irq_enable();

 Enable_cpus:
	enable_nonboot_cpus();

 Platform_finish:
	hibernation_ops->finish();

	dpm_resume_start(PMSG_RESTORE);

 Resume_devices:
	entering_platform_hibernation = false;
	dpm_resume_end(PMSG_RESTORE);
	resume_console();

 Close:
	hibernation_ops->end();

	return error;
}

/**
 * power_down - Shut the machine down for hibernation.
 *
 * Use the platform driver, if configured, to put the system into the sleep
 * state corresponding to hibernation, or try to power it off or reboot,
 * depending on the value of hibernation_mode.
 */
static void power_down(void)
{
#ifdef CONFIG_SUSPEND
	int error;

	if (hibernation_mode == HIBERNATION_SUSPEND) {
		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
		if (error) {
			hibernation_mode = hibernation_ops ?
						HIBERNATION_PLATFORM :
						HIBERNATION_SHUTDOWN;
		} else {
			/* Restore swap signature. */
			error = swsusp_unmark();
			if (error)
				pr_err("Swap will be unusable! Try swapon -a.\n");

			return;
		}
	}
#endif

	switch (hibernation_mode) {
	case HIBERNATION_REBOOT:
		kernel_restart(NULL);
		break;
	case HIBERNATION_PLATFORM:
		hibernation_platform_enter();
	case HIBERNATION_SHUTDOWN:
		if (pm_power_off)
			kernel_power_off();
		break;
	}
	kernel_halt();
	/*
	 * Valid image is on the disk, if we continue we risk serious data
	 * corruption after resume.
	 */
	pr_crit("Power down manually\n");
	while (1)
		cpu_relax();
}

static int load_image_and_restore(void)
{
	int error;
	unsigned int flags;

	pm_pr_dbg("Loading hibernation image.\n");

	lock_device_hotplug();
	error = create_basic_memory_bitmaps();
	if (error)
		goto Unlock;

	error = swsusp_read(&flags);
	swsusp_close(FMODE_READ);
	if (!error)
		hibernation_restore(flags & SF_PLATFORM_MODE);

	pr_err("Failed to load hibernation image, recovering.\n");
	swsusp_free();
	free_basic_memory_bitmaps();
 Unlock:
	unlock_device_hotplug();

	return error;
}

/**
 * hibernate - Carry out system hibernation, including saving the image.
 */
int hibernate(void)
{
	int error, nr_calls = 0;
	bool snapshot_test = false;

	if (!hibernation_available()) {
		pm_pr_dbg("Hibernation not available.\n");
		return -EPERM;
	}

	lock_system_sleep();
	/* The snapshot device should not be opened while we're running */
	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
		error = -EBUSY;
		goto Unlock;
	}

	pr_info("hibernation entry\n");
	pm_prepare_console();
	error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
	if (error) {
		nr_calls--;
		goto Exit;
	}

	pr_info("Syncing filesystems ... \n");
	sys_sync();
	pr_info("done.\n");

	error = freeze_processes();
	if (error)
		goto Exit;

	lock_device_hotplug();
	/* Allocate memory management structures */
	error = create_basic_memory_bitmaps();
	if (error)
		goto Thaw;

	error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
	if (error || freezer_test_done)
		goto Free_bitmaps;

	if (in_suspend) {
		unsigned int flags = 0;

		if (hibernation_mode == HIBERNATION_PLATFORM)
			flags |= SF_PLATFORM_MODE;
		if (nocompress)
			flags |= SF_NOCOMPRESS_MODE;
		else
		        flags |= SF_CRC32_MODE;

		pm_pr_dbg("Writing image.\n");
		error = swsusp_write(flags);
		swsusp_free();
		if (!error) {
			if (hibernation_mode == HIBERNATION_TEST_RESUME)
				snapshot_test = true;
			else
				power_down();
		}
		in_suspend = 0;
		pm_restore_gfp_mask();
	} else {
		pm_pr_dbg("Image restored successfully.\n");
	}

 Free_bitmaps:
	free_basic_memory_bitmaps();
 Thaw:
	unlock_device_hotplug();
	if (snapshot_test) {
		pm_pr_dbg("Checking hibernation image\n");
		error = swsusp_check();
		if (!error)
			error = load_image_and_restore();
	}
	thaw_processes();

	/* Don't bother checking whether freezer_test_done is true */
	freezer_test_done = false;
 Exit:
	__pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
	pm_restore_console();
	atomic_inc(&snapshot_device_available);
 Unlock:
	unlock_system_sleep();
	pr_info("hibernation exit\n");

	return error;
}


/**
 * software_resume - Resume from a saved hibernation image.
 *
 * This routine is called as a late initcall, when all devices have been
 * discovered and initialized already.
 *
 * The image reading code is called to see if there is a hibernation image
 * available for reading.  If that is the case, devices are quiesced and the
 * contents of memory is restored from the saved image.
 *
 * If this is successful, control reappears in the restored target kernel in
 * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 * attempts to recover gracefully and make the kernel return to the normal mode
 * of operation.
 */
static int software_resume(void)
{
	int error, nr_calls = 0;

	/*
	 * If the user said "noresume".. bail out early.
	 */
	if (noresume || !hibernation_available())
		return 0;

	/*
	 * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
	 * is configured into the kernel. Since the regular hibernate
	 * trigger path is via sysfs which takes a buffer mutex before
	 * calling hibernate functions (which take pm_mutex) this can
	 * cause lockdep to complain about a possible ABBA deadlock
	 * which cannot happen since we're in the boot code here and
	 * sysfs can't be invoked yet. Therefore, we use a subclass
	 * here to avoid lockdep complaining.
	 */
	mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);

	if (swsusp_resume_device)
		goto Check_image;

	if (!strlen(resume_file)) {
		error = -ENOENT;
		goto Unlock;
	}

	pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);

	if (resume_delay) {
		pr_info("Waiting %dsec before reading resume device ...\n",
			resume_delay);
		ssleep(resume_delay);
	}

	/* Check if the device is there */
	swsusp_resume_device = name_to_dev_t(resume_file);

	/*
	 * name_to_dev_t is ineffective to verify parition if resume_file is in
	 * integer format. (e.g. major:minor)
	 */
	if (isdigit(resume_file[0]) && resume_wait) {
		int partno;
		while (!get_gendisk(swsusp_resume_device, &partno))
			msleep(10);
	}

	if (!swsusp_resume_device) {
		/*
		 * Some device discovery might still be in progress; we need
		 * to wait for this to finish.
		 */
		wait_for_device_probe();

		if (resume_wait) {
			while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
				msleep(10);
			async_synchronize_full();
		}

		swsusp_resume_device = name_to_dev_t(resume_file);
		if (!swsusp_resume_device) {
			error = -ENODEV;
			goto Unlock;
		}
	}

 Check_image:
	pm_pr_dbg("Hibernation image partition %d:%d present\n",
		MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));

	pm_pr_dbg("Looking for hibernation image.\n");
	error = swsusp_check();
	if (error)
		goto Unlock;

	/* The snapshot device should not be opened while we're running */
	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
		error = -EBUSY;
		swsusp_close(FMODE_READ);
		goto Unlock;
	}

	pr_info("resume from hibernation\n");
	pm_prepare_console();
	error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
	if (error) {
		nr_calls--;
		goto Close_Finish;
	}

	pm_pr_dbg("Preparing processes for restore.\n");
	error = freeze_processes();
	if (error)
		goto Close_Finish;
	error = load_image_and_restore();
	thaw_processes();
 Finish:
	__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
	pm_restore_console();
	pr_info("resume from hibernation failed (%d)\n", error);
	atomic_inc(&snapshot_device_available);
	/* For success case, the suspend path will release the lock */
 Unlock:
	mutex_unlock(&pm_mutex);
	pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
	return error;
 Close_Finish:
	swsusp_close(FMODE_READ);
	goto Finish;
}

late_initcall_sync(software_resume);


static const char * const hibernation_modes[] = {
	[HIBERNATION_PLATFORM]	= "platform",
	[HIBERNATION_SHUTDOWN]	= "shutdown",
	[HIBERNATION_REBOOT]	= "reboot",
#ifdef CONFIG_SUSPEND
	[HIBERNATION_SUSPEND]	= "suspend",
#endif
	[HIBERNATION_TEST_RESUME]	= "test_resume",
};

/*
 * /sys/power/disk - Control hibernation mode.
 *
 * Hibernation can be handled in several ways.  There are a few different ways
 * to put the system into the sleep state: using the platform driver (e.g. ACPI
 * or other hibernation_ops), powering it off or rebooting it (for testing
 * mostly).
 *
 * The sysfs file /sys/power/disk provides an interface for selecting the
 * hibernation mode to use.  Reading from this file causes the available modes
 * to be printed.  There are 3 modes that can be supported:
 *
 *	'platform'
 *	'shutdown'
 *	'reboot'
 *
 * If a platform hibernation driver is in use, 'platform' will be supported
 * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 * The selected option (i.e. the one corresponding to the current value of
 * hibernation_mode) is enclosed by a square bracket.
 *
 * To select a given hibernation mode it is necessary to write the mode's
 * string representation (as returned by reading from /sys/power/disk) back
 * into /sys/power/disk.
 */

static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
			 char *buf)
{
	int i;
	char *start = buf;

	if (!hibernation_available())
		return sprintf(buf, "[disabled]\n");

	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
		if (!hibernation_modes[i])
			continue;
		switch (i) {
		case HIBERNATION_SHUTDOWN:
		case HIBERNATION_REBOOT:
#ifdef CONFIG_SUSPEND
		case HIBERNATION_SUSPEND:
#endif
		case HIBERNATION_TEST_RESUME:
			break;
		case HIBERNATION_PLATFORM:
			if (hibernation_ops)
				break;
			/* not a valid mode, continue with loop */
			continue;
		}
		if (i == hibernation_mode)
			buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
		else
			buf += sprintf(buf, "%s ", hibernation_modes[i]);
	}
	buf += sprintf(buf, "\n");
	return buf-start;
}

static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
			  const char *buf, size_t n)
{
	int error = 0;
	int i;
	int len;
	char *p;
	int mode = HIBERNATION_INVALID;

	if (!hibernation_available())
		return -EPERM;

	p = memchr(buf, '\n', n);
	len = p ? p - buf : n;

	lock_system_sleep();
	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
		if (len == strlen(hibernation_modes[i])
		    && !strncmp(buf, hibernation_modes[i], len)) {
			mode = i;
			break;
		}
	}
	if (mode != HIBERNATION_INVALID) {
		switch (mode) {
		case HIBERNATION_SHUTDOWN:
		case HIBERNATION_REBOOT:
#ifdef CONFIG_SUSPEND
		case HIBERNATION_SUSPEND:
#endif
		case HIBERNATION_TEST_RESUME:
			hibernation_mode = mode;
			break;
		case HIBERNATION_PLATFORM:
			if (hibernation_ops)
				hibernation_mode = mode;
			else
				error = -EINVAL;
		}
	} else
		error = -EINVAL;

	if (!error)
		pm_pr_dbg("Hibernation mode set to '%s'\n",
			       hibernation_modes[mode]);
	unlock_system_sleep();
	return error ? error : n;
}

power_attr(disk);

static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
			   char *buf)
{
	return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
		       MINOR(swsusp_resume_device));
}

static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
			    const char *buf, size_t n)
{
	dev_t res;
	int len = n;
	char *name;

	if (len && buf[len-1] == '\n')
		len--;
	name = kstrndup(buf, len, GFP_KERNEL);
	if (!name)
		return -ENOMEM;

	res = name_to_dev_t(name);
	kfree(name);
	if (!res)
		return -EINVAL;

	lock_system_sleep();
	swsusp_resume_device = res;
	unlock_system_sleep();
	pr_info("Starting manual resume from disk\n");
	noresume = 0;
	software_resume();
	return n;
}

power_attr(resume);

static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
			       char *buf)
{
	return sprintf(buf, "%lu\n", image_size);
}

static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
				const char *buf, size_t n)
{
	unsigned long size;

	if (sscanf(buf, "%lu", &size) == 1) {
		image_size = size;
		return n;
	}

	return -EINVAL;
}

power_attr(image_size);

static ssize_t reserved_size_show(struct kobject *kobj,
				  struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%lu\n", reserved_size);
}

static ssize_t reserved_size_store(struct kobject *kobj,
				   struct kobj_attribute *attr,
				   const char *buf, size_t n)
{
	unsigned long size;

	if (sscanf(buf, "%lu", &size) == 1) {
		reserved_size = size;
		return n;
	}

	return -EINVAL;
}

power_attr(reserved_size);

static struct attribute * g[] = {
	&disk_attr.attr,
	&resume_attr.attr,
	&image_size_attr.attr,
	&reserved_size_attr.attr,
	NULL,
};


static const struct attribute_group attr_group = {
	.attrs = g,
};


static int __init pm_disk_init(void)
{
	return sysfs_create_group(power_kobj, &attr_group);
}

core_initcall(pm_disk_init);


static int __init resume_setup(char *str)
{
	if (noresume)
		return 1;

	strncpy( resume_file, str, 255 );
	return 1;
}

static int __init resume_offset_setup(char *str)
{
	unsigned long long offset;

	if (noresume)
		return 1;

	if (sscanf(str, "%llu", &offset) == 1)
		swsusp_resume_block = offset;

	return 1;
}

static int __init hibernate_setup(char *str)
{
	if (!strncmp(str, "noresume", 8)) {
		noresume = 1;
	} else if (!strncmp(str, "nocompress", 10)) {
		nocompress = 1;
	} else if (!strncmp(str, "no", 2)) {
		noresume = 1;
		nohibernate = 1;
	} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
		   && !strncmp(str, "protect_image", 13)) {
		enable_restore_image_protection();
	}
	return 1;
}

static int __init noresume_setup(char *str)
{
	noresume = 1;
	return 1;
}

static int __init resumewait_setup(char *str)
{
	resume_wait = 1;
	return 1;
}

static int __init resumedelay_setup(char *str)
{
	int rc = kstrtouint(str, 0, &resume_delay);

	if (rc)
		return rc;
	return 1;
}

static int __init nohibernate_setup(char *str)
{
	noresume = 1;
	nohibernate = 1;
	return 1;
}

__setup("noresume", noresume_setup);
__setup("resume_offset=", resume_offset_setup);
__setup("resume=", resume_setup);
__setup("hibernate=", hibernate_setup);
__setup("resumewait", resumewait_setup);
__setup("resumedelay=", resumedelay_setup);
__setup("nohibernate", nohibernate_setup);