aboutsummaryrefslogtreecommitdiffstats
path: root/flashrom.c
blob: 8e4300167d6a67048f40cc709ee155f27603cc2f (plain)
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
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
/*
 * This file is part of the flashrom project.
 *
 * Copyright (C) 2000 Silicon Integrated System Corporation
 * Copyright (C) 2004 Tyan Corp <yhlu@tyan.com>
 * Copyright (C) 2005-2008 coresystems GmbH
 * Copyright (C) 2008,2009 Carl-Daniel Hailfinger
 * Copyright (C) 2016 secunet Security Networks AG
 * (Written by Nico Huber <nico.huber@secunet.com> for secunet)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <stdio.h>
#include <sys/types.h>
#ifndef __LIBPAYLOAD__
#include <fcntl.h>
#include <sys/stat.h>
#endif
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#if HAVE_UTSNAME == 1
#include <sys/utsname.h>
#endif
#include "flash.h"
#include "flashchips.h"
#include "programmer.h"
#include "hwaccess_physmap.h"
#include "chipdrivers.h"

const char flashrom_version[] = FLASHROM_VERSION;
const char *chip_to_probe = NULL;

static const struct programmer_entry *programmer = NULL;
static const char *programmer_param = NULL;

/*
 * Programmers supporting multiple buses can have differing size limits on
 * each bus. Store the limits for each bus in a common struct.
 */
struct decode_sizes max_rom_decode;

/* If nonzero, used as the start address of bottom-aligned flash. */
unsigned long flashbase;

/* Is writing allowed with this programmer? */
int programmer_may_write;

#define SHUTDOWN_MAXFN 32
static int shutdown_fn_count = 0;
/** @private */
static struct shutdown_func_data {
	int (*func) (void *data);
	void *data;
} shutdown_fn[SHUTDOWN_MAXFN];
/* Initialize to 0 to make sure nobody registers a shutdown function before
 * programmer init.
 */
static int may_register_shutdown = 0;

/* Did we change something or was every erase/write skipped (if any)? */
static bool all_skipped = true;

/* Register a function to be executed on programmer shutdown.
 * The advantage over atexit() is that you can supply a void pointer which will
 * be used as parameter to the registered function upon programmer shutdown.
 * This pointer can point to arbitrary data used by said function, e.g. undo
 * information for GPIO settings etc. If unneeded, set data=NULL.
 * Please note that the first (void *data) belongs to the function signature of
 * the function passed as first parameter.
 */
int register_shutdown(int (*function) (void *data), void *data)
{
	if (shutdown_fn_count >= SHUTDOWN_MAXFN) {
		msg_perr("Tried to register more than %i shutdown functions.\n",
			 SHUTDOWN_MAXFN);
		return 1;
	}
	if (!may_register_shutdown) {
		msg_perr("Tried to register a shutdown function before "
			 "programmer init.\n");
		return 1;
	}
	shutdown_fn[shutdown_fn_count].func = function;
	shutdown_fn[shutdown_fn_count].data = data;
	shutdown_fn_count++;

	return 0;
}

int register_chip_restore(chip_restore_fn_cb_t func,
			  struct flashctx *flash, uint8_t status)
{
	if (flash->chip_restore_fn_count >= MAX_CHIP_RESTORE_FUNCTIONS) {
		msg_perr("Tried to register more than %i chip restore"
		         " functions.\n", MAX_CHIP_RESTORE_FUNCTIONS);
		return 1;
	}
	flash->chip_restore_fn[flash->chip_restore_fn_count].func = func;
	flash->chip_restore_fn[flash->chip_restore_fn_count].status = status;
	flash->chip_restore_fn_count++;

	return 0;
}

static int deregister_chip_restore(struct flashctx *flash)
{
	int rc = 0;

	while (flash->chip_restore_fn_count > 0) {
		int i = --flash->chip_restore_fn_count;
		rc |= flash->chip_restore_fn[i].func(
			flash, flash->chip_restore_fn[i].status);
	}

	return rc;
}

int programmer_init(const struct programmer_entry *prog, const char *param)
{
	int ret;

	if (prog == NULL) {
		msg_perr("Invalid programmer specified!\n");
		return -1;
	}
	programmer = prog;
	/* Initialize all programmer specific data. */
	/* Default to unlimited decode sizes. */
	max_rom_decode = (const struct decode_sizes) {
		.parallel	= 0xffffffff,
		.lpc		= 0xffffffff,
		.fwh		= 0xffffffff,
		.spi		= 0xffffffff,
	};
	/* Default to top aligned flash at 4 GB. */
	flashbase = 0;
	/* Registering shutdown functions is now allowed. */
	may_register_shutdown = 1;
	/* Default to allowing writes. Broken programmers set this to 0. */
	programmer_may_write = 1;

	programmer_param = param;
	msg_pdbg("Initializing %s programmer\n", programmer->name);
	ret = programmer->init();
	if (programmer_param && strlen(programmer_param)) {
		if (ret != 0) {
			/* It is quite possible that any unhandled programmer parameter would have been valid,
			 * but an error in actual programmer init happened before the parameter was evaluated.
			 */
			msg_pwarn("Unhandled programmer parameters (possibly due to another failure): %s\n",
				  programmer_param);
		} else {
			/* Actual programmer init was successful, but the user specified an invalid or unusable
			 * (for the current programmer configuration) parameter.
			 */
			msg_perr("Unhandled programmer parameters: %s\n", programmer_param);
			msg_perr("Aborting.\n");
			ret = ERROR_FATAL;
		}
	}
	return ret;
}

/** Calls registered shutdown functions and resets internal programmer-related variables.
 * Calling it is safe even without previous initialization, but further interactions with programmer support
 * require a call to programmer_init() (afterwards).
 *
 * @return The OR-ed result values of all shutdown functions (i.e. 0 on success). */
int programmer_shutdown(void)
{
	int ret = 0;

	/* Registering shutdown functions is no longer allowed. */
	may_register_shutdown = 0;
	while (shutdown_fn_count > 0) {
		int i = --shutdown_fn_count;
		ret |= shutdown_fn[i].func(shutdown_fn[i].data);
	}

	programmer_param = NULL;
	registered_master_count = 0;

	return ret;
}

void *programmer_map_flash_region(const char *descr, uintptr_t phys_addr, size_t len)
{
	void *ret = programmer->map_flash_region(descr, phys_addr, len);
	msg_gspew("%s: mapping %s from 0x%0*" PRIxPTR " to 0x%0*" PRIxPTR "\n",
		  __func__, descr, PRIxPTR_WIDTH, phys_addr, PRIxPTR_WIDTH, (uintptr_t) ret);
	return ret;
}

void programmer_unmap_flash_region(void *virt_addr, size_t len)
{
	programmer->unmap_flash_region(virt_addr, len);
	msg_gspew("%s: unmapped 0x%0*" PRIxPTR "\n", __func__, PRIxPTR_WIDTH, (uintptr_t)virt_addr);
}

void chip_writeb(const struct flashctx *flash, uint8_t val, chipaddr addr)
{
	flash->mst->par.chip_writeb(flash, val, addr);
}

void chip_writew(const struct flashctx *flash, uint16_t val, chipaddr addr)
{
	flash->mst->par.chip_writew(flash, val, addr);
}

void chip_writel(const struct flashctx *flash, uint32_t val, chipaddr addr)
{
	flash->mst->par.chip_writel(flash, val, addr);
}

void chip_writen(const struct flashctx *flash, const uint8_t *buf, chipaddr addr, size_t len)
{
	flash->mst->par.chip_writen(flash, buf, addr, len);
}

uint8_t chip_readb(const struct flashctx *flash, const chipaddr addr)
{
	return flash->mst->par.chip_readb(flash, addr);
}

uint16_t chip_readw(const struct flashctx *flash, const chipaddr addr)
{
	return flash->mst->par.chip_readw(flash, addr);
}

uint32_t chip_readl(const struct flashctx *flash, const chipaddr addr)
{
	return flash->mst->par.chip_readl(flash, addr);
}

void chip_readn(const struct flashctx *flash, uint8_t *buf, chipaddr addr,
		size_t len)
{
	flash->mst->par.chip_readn(flash, buf, addr, len);
}

void programmer_delay(unsigned int usecs)
{
	if (usecs > 0)
		programmer->delay(usecs);
}

int read_memmapped(struct flashctx *flash, uint8_t *buf, unsigned int start,
		   int unsigned len)
{
	chip_readn(flash, buf, flash->virtual_memory + start, len);

	return 0;
}

/* This is a somewhat hacked function similar in some ways to strtok().
 * It will look for needle with a subsequent '=' in haystack, return a copy of
 * needle and remove everything from the first occurrence of needle to the next
 * delimiter from haystack.
 */
static char *extract_param(const char *const *haystack, const char *needle, const char *delim)
{
	char *param_pos, *opt_pos, *rest;
	char *opt = NULL;
	int optlen;
	int needlelen;

	needlelen = strlen(needle);
	if (!needlelen) {
		msg_gerr("%s: empty needle! Please report a bug at "
			 "flashrom@flashrom.org\n", __func__);
		return NULL;
	}
	/* No programmer parameters given. */
	if (*haystack == NULL)
		return NULL;
	param_pos = strstr(*haystack, needle);
	do {
		if (!param_pos)
			return NULL;
		/* Needle followed by '='? */
		if (param_pos[needlelen] == '=') {
			/* Beginning of the string? */
			if (param_pos == *haystack)
				break;
			/* After a delimiter? */
			if (strchr(delim, *(param_pos - 1)))
				break;
		}
		/* Continue searching. */
		param_pos++;
		param_pos = strstr(param_pos, needle);
	} while (1);

	if (param_pos) {
		/* Get the string after needle and '='. */
		opt_pos = param_pos + needlelen + 1;
		optlen = strcspn(opt_pos, delim);
		/* Return an empty string if the parameter was empty. */
		opt = malloc(optlen + 1);
		if (!opt) {
			msg_gerr("Out of memory!\n");
			exit(1);
		}
		strncpy(opt, opt_pos, optlen);
		opt[optlen] = '\0';
		rest = opt_pos + optlen;
		/* Skip all delimiters after the current parameter. */
		rest += strspn(rest, delim);
		memmove(param_pos, rest, strlen(rest) + 1);
		/* We could shrink haystack, but the effort is not worth it. */
	}

	return opt;
}

char *extract_programmer_param(const char *param_name)
{
	return extract_param(&programmer_param, param_name, ",");
}

static int check_block_eraser(const struct flashctx *flash, int k, int log)
{
	struct block_eraser eraser = flash->chip->block_erasers[k];

	if (!eraser.block_erase && !eraser.eraseblocks[0].count) {
		if (log)
			msg_cdbg("not defined. ");
		return 1;
	}
	if (!eraser.block_erase && eraser.eraseblocks[0].count) {
		if (log)
			msg_cdbg("eraseblock layout is known, but matching "
				 "block erase function is not implemented. ");
		return 1;
	}
	if (eraser.block_erase && !eraser.eraseblocks[0].count) {
		if (log)
			msg_cdbg("block erase function found, but "
				 "eraseblock layout is not defined. ");
		return 1;
	}
	// TODO: Once erase functions are annotated with allowed buses, check that as well.
	return 0;
}

/* Returns the number of well-defined erasers for a chip. */
static unsigned int count_usable_erasers(const struct flashctx *flash)
{
	unsigned int usable_erasefunctions = 0;
	int k;
	for (k = 0; k < NUM_ERASEFUNCTIONS; k++) {
		if (!check_block_eraser(flash, k, 0))
			usable_erasefunctions++;
	}
	return usable_erasefunctions;
}

static int compare_range(const uint8_t *wantbuf, const uint8_t *havebuf, unsigned int start, unsigned int len)
{
	int ret = 0, failcount = 0;
	unsigned int i;
	for (i = 0; i < len; i++) {
		if (wantbuf[i] != havebuf[i]) {
			/* Only print the first failure. */
			if (!failcount++)
				msg_cerr("FAILED at 0x%08x! Expected=0x%02x, Found=0x%02x,",
					 start + i, wantbuf[i], havebuf[i]);
		}
	}
	if (failcount) {
		msg_cerr(" failed byte count from 0x%08x-0x%08x: 0x%x\n",
			 start, start + len - 1, failcount);
		ret = -1;
	}
	return ret;
}

/* start is an offset to the base address of the flash chip */
static int check_erased_range(struct flashctx *flash, unsigned int start, unsigned int len)
{
	int ret;
	uint8_t *cmpbuf = malloc(len);
	const uint8_t erased_value = ERASED_VALUE(flash);

	if (!cmpbuf) {
		msg_gerr("Could not allocate memory!\n");
		exit(1);
	}
	memset(cmpbuf, erased_value, len);
	ret = verify_range(flash, cmpbuf, start, len);
	free(cmpbuf);
	return ret;
}

/*
 * @cmpbuf	buffer to compare against, cmpbuf[0] is expected to match the
 *		flash content at location start
 * @start	offset to the base address of the flash chip
 * @len		length of the verified area
 * @return	0 for success, -1 for failure
 */
int verify_range(struct flashctx *flash, const uint8_t *cmpbuf, unsigned int start, unsigned int len)
{
	if (!len)
		return -1;

	if (start + len > flash->chip->total_size * 1024) {
		msg_gerr("Error: %s called with start 0x%x + len 0x%x >"
			" total_size 0x%x\n", __func__, start, len,
			flash->chip->total_size * 1024);
		return -1;
	}

	if (!flash->chip->read) {
		msg_cerr("ERROR: flashrom has no read function for this flash chip.\n");
		return -1;
	}

	uint8_t *readbuf = malloc(len);
	if (!readbuf) {
		msg_gerr("Could not allocate memory!\n");
		return -1;
	}

	int ret = flash->chip->read(flash, readbuf, start, len);
	if (ret) {
		msg_gerr("Verification impossible because read failed "
			 "at 0x%x (len 0x%x)\n", start, len);
		ret = -1;
		goto out_free;
	}

	ret = compare_range(cmpbuf, readbuf, start, len);
out_free:
	free(readbuf);
	return ret;
}

/* Helper function for need_erase() that focuses on granularities of gran bytes. */
static int need_erase_gran_bytes(const uint8_t *have, const uint8_t *want, unsigned int len,
                                 unsigned int gran, const uint8_t erased_value)
{
	unsigned int i, j, limit;
	for (j = 0; j < len / gran; j++) {
		limit = min (gran, len - j * gran);
		/* Are 'have' and 'want' identical? */
		if (!memcmp(have + j * gran, want + j * gran, limit))
			continue;
		/* have needs to be in erased state. */
		for (i = 0; i < limit; i++)
			if (have[j * gran + i] != erased_value)
				return 1;
	}
	return 0;
}

/*
 * Check if the buffer @have can be programmed to the content of @want without
 * erasing. This is only possible if all chunks of size @gran are either kept
 * as-is or changed from an all-ones state to any other state.
 *
 * Warning: This function assumes that @have and @want point to naturally
 * aligned regions.
 *
 * @have        buffer with current content
 * @want        buffer with desired content
 * @len		length of the checked area
 * @gran	write granularity (enum, not count)
 * @return      0 if no erase is needed, 1 otherwise
 */
static int need_erase(const uint8_t *have, const uint8_t *want, unsigned int len,
               enum write_granularity gran, const uint8_t erased_value)
{
	int result = 0;
	unsigned int i;

	switch (gran) {
	case write_gran_1bit:
		for (i = 0; i < len; i++)
			if ((have[i] & want[i]) != want[i]) {
				result = 1;
				break;
			}
		break;
	case write_gran_1byte:
		for (i = 0; i < len; i++)
			if ((have[i] != want[i]) && (have[i] != erased_value)) {
				result = 1;
				break;
			}
		break;
	case write_gran_128bytes:
		result = need_erase_gran_bytes(have, want, len, 128, erased_value);
		break;
	case write_gran_256bytes:
		result = need_erase_gran_bytes(have, want, len, 256, erased_value);
		break;
	case write_gran_264bytes:
		result = need_erase_gran_bytes(have, want, len, 264, erased_value);
		break;
	case write_gran_512bytes:
		result = need_erase_gran_bytes(have, want, len, 512, erased_value);
		break;
	case write_gran_528bytes:
		result = need_erase_gran_bytes(have, want, len, 528, erased_value);
		break;
	case write_gran_1024bytes:
		result = need_erase_gran_bytes(have, want, len, 1024, erased_value);
		break;
	case write_gran_1056bytes:
		result = need_erase_gran_bytes(have, want, len, 1056, erased_value);
		break;
	case write_gran_1byte_implicit_erase:
		/* Do not erase, handle content changes from anything->0xff by writing 0xff. */
		result = 0;
		break;
	default:
		msg_cerr("%s: Unsupported granularity! Please report a bug at "
			 "flashrom@flashrom.org\n", __func__);
	}
	return result;
}

/**
 * Check if the buffer @have needs to be programmed to get the content of @want.
 * If yes, return 1 and fill in first_start with the start address of the
 * write operation and first_len with the length of the first to-be-written
 * chunk. If not, return 0 and leave first_start and first_len undefined.
 *
 * Warning: This function assumes that @have and @want point to naturally
 * aligned regions.
 *
 * @have	buffer with current content
 * @want	buffer with desired content
 * @len		length of the checked area
 * @gran	write granularity (enum, not count)
 * @first_start	offset of the first byte which needs to be written (passed in
 *		value is increased by the offset of the first needed write
 *		relative to have/want or unchanged if no write is needed)
 * @return	length of the first contiguous area which needs to be written
 *		0 if no write is needed
 *
 * FIXME: This function needs a parameter which tells it about coalescing
 * in relation to the max write length of the programmer and the max write
 * length of the chip.
 */
static unsigned int get_next_write(const uint8_t *have, const uint8_t *want, unsigned int len,
			  unsigned int *first_start,
			  enum write_granularity gran)
{
	int need_write = 0;
	unsigned int rel_start = 0, first_len = 0;
	unsigned int i, limit, stride;

	switch (gran) {
	case write_gran_1bit:
	case write_gran_1byte:
	case write_gran_1byte_implicit_erase:
		stride = 1;
		break;
	case write_gran_128bytes:
		stride = 128;
		break;
	case write_gran_256bytes:
		stride = 256;
		break;
	case write_gran_264bytes:
		stride = 264;
		break;
	case write_gran_512bytes:
		stride = 512;
		break;
	case write_gran_528bytes:
		stride = 528;
		break;
	case write_gran_1024bytes:
		stride = 1024;
		break;
	case write_gran_1056bytes:
		stride = 1056;
		break;
	default:
		msg_cerr("%s: Unsupported granularity! Please report a bug at "
			 "flashrom@flashrom.org\n", __func__);
		/* Claim that no write was needed. A write with unknown
		 * granularity is too dangerous to try.
		 */
		return 0;
	}
	for (i = 0; i < len / stride; i++) {
		limit = min(stride, len - i * stride);
		/* Are 'have' and 'want' identical? */
		if (memcmp(have + i * stride, want + i * stride, limit)) {
			if (!need_write) {
				/* First location where have and want differ. */
				need_write = 1;
				rel_start = i * stride;
			}
		} else {
			if (need_write) {
				/* First location where have and want
				 * do not differ anymore.
				 */
				break;
			}
		}
	}
	if (need_write)
		first_len = min(i * stride - rel_start, len);
	*first_start += rel_start;
	return first_len;
}

/* Returns the number of buses commonly supported by the current programmer and flash chip where the latter
 * can not be completely accessed due to size/address limits of the programmer. */
unsigned int count_max_decode_exceedings(const struct flashctx *flash)
{
	unsigned int limitexceeded = 0;
	uint32_t size = flash->chip->total_size * 1024;
	enum chipbustype buses = flash->mst->buses_supported & flash->chip->bustype;

	if ((buses & BUS_PARALLEL) && (max_rom_decode.parallel < size)) {
		limitexceeded++;
		msg_pdbg("Chip size %u kB is bigger than supported "
			 "size %u kB of chipset/board/programmer "
			 "for %s interface, "
			 "probe/read/erase/write may fail. ", size / 1024,
			 max_rom_decode.parallel / 1024, "Parallel");
	}
	if ((buses & BUS_LPC) && (max_rom_decode.lpc < size)) {
		limitexceeded++;
		msg_pdbg("Chip size %u kB is bigger than supported "
			 "size %u kB of chipset/board/programmer "
			 "for %s interface, "
			 "probe/read/erase/write may fail. ", size / 1024,
			 max_rom_decode.lpc / 1024, "LPC");
	}
	if ((buses & BUS_FWH) && (max_rom_decode.fwh < size)) {
		limitexceeded++;
		msg_pdbg("Chip size %u kB is bigger than supported "
			 "size %u kB of chipset/board/programmer "
			 "for %s interface, "
			 "probe/read/erase/write may fail. ", size / 1024,
			 max_rom_decode.fwh / 1024, "FWH");
	}
	if ((buses & BUS_SPI) && (max_rom_decode.spi < size)) {
		limitexceeded++;
		msg_pdbg("Chip size %u kB is bigger than supported "
			 "size %u kB of chipset/board/programmer "
			 "for %s interface, "
			 "probe/read/erase/write may fail. ", size / 1024,
			 max_rom_decode.spi / 1024, "SPI");
	}
	return limitexceeded;
}

void unmap_flash(struct flashctx *flash)
{
	if (flash->virtual_registers != (chipaddr)ERROR_PTR) {
		programmer_unmap_flash_region((void *)flash->virtual_registers, flash->chip->total_size * 1024);
		flash->physical_registers = 0;
		flash->virtual_registers = (chipaddr)ERROR_PTR;
	}

	if (flash->virtual_memory != (chipaddr)ERROR_PTR) {
		programmer_unmap_flash_region((void *)flash->virtual_memory, flash->chip->total_size * 1024);
		flash->physical_memory = 0;
		flash->virtual_memory = (chipaddr)ERROR_PTR;
	}
}

int map_flash(struct flashctx *flash)
{
	/* Init pointers to the fail-safe state to distinguish them later from legit values. */
	flash->virtual_memory = (chipaddr)ERROR_PTR;
	flash->virtual_registers = (chipaddr)ERROR_PTR;

	/* FIXME: This avoids mapping (and unmapping) of flash chip definitions with size 0.
	 * These are used for various probing-related hacks that would not map successfully anyway and should be
	 * removed ASAP. */
	if (flash->chip->total_size == 0)
		return 0;

	const chipsize_t size = flash->chip->total_size * 1024;
	uintptr_t base = flashbase ? flashbase : (0xffffffff - size + 1);
	void *addr = programmer_map_flash_region(flash->chip->name, base, size);
	if (addr == ERROR_PTR) {
		msg_perr("Could not map flash chip %s at 0x%0*" PRIxPTR ".\n",
			 flash->chip->name, PRIxPTR_WIDTH, base);
		return 1;
	}
	flash->physical_memory = base;
	flash->virtual_memory = (chipaddr)addr;

	/* FIXME: Special function registers normally live 4 MByte below flash space, but it might be somewhere
	 * completely different on some chips and programmers, or not mappable at all.
	 * Ignore these problems for now and always report success. */
	if (flash->chip->feature_bits & FEATURE_REGISTERMAP) {
		base = 0xffffffff - size - 0x400000 + 1;
		addr = programmer_map_flash_region("flash chip registers", base, size);
		if (addr == ERROR_PTR) {
			msg_pdbg2("Could not map flash chip registers %s at 0x%0*" PRIxPTR ".\n",
				 flash->chip->name, PRIxPTR_WIDTH, base);
			return 0;
		}
		flash->physical_registers = base;
		flash->virtual_registers = (chipaddr)addr;
	}
	return 0;
}

/*
 * Return a string corresponding to the bustype parameter.
 * Memory is obtained with malloc() and must be freed with free() by the caller.
 */
char *flashbuses_to_text(enum chipbustype bustype)
{
	char *ret = calloc(1, 1);
	/*
	 * FIXME: Once all chipsets and flash chips have been updated, NONSPI
	 * will cease to exist and should be eliminated here as well.
	 */
	if (bustype == BUS_NONSPI) {
		ret = strcat_realloc(ret, "Non-SPI, ");
	} else {
		if (bustype & BUS_PARALLEL)
			ret = strcat_realloc(ret, "Parallel, ");
		if (bustype & BUS_LPC)
			ret = strcat_realloc(ret, "LPC, ");
		if (bustype & BUS_FWH)
			ret = strcat_realloc(ret, "FWH, ");
		if (bustype & BUS_SPI)
			ret = strcat_realloc(ret, "SPI, ");
		if (bustype & BUS_PROG)
			ret = strcat_realloc(ret, "Programmer-specific, ");
		if (bustype == BUS_NONE)
			ret = strcat_realloc(ret, "None, ");
	}
	/* Kill last comma. */
	ret[strlen(ret) - 2] = '\0';
	ret = realloc(ret, strlen(ret) + 1);
	return ret;
}

int probe_flash(struct registered_master *mst, int startchip, struct flashctx *flash, int force)
{
	const struct flashchip *chip;
	enum chipbustype buses_common;
	char *tmp;

	for (chip = flashchips + startchip; chip && chip->name; chip++) {
		if (chip_to_probe && strcmp(chip->name, chip_to_probe) != 0)
			continue;
		buses_common = mst->buses_supported & chip->bustype;
		if (!buses_common)
			continue;
		/* Only probe for SPI25 chips by default. */
		if (chip->bustype == BUS_SPI && !chip_to_probe && chip->spi_cmd_set != SPI25)
			continue;
		msg_gdbg("Probing for %s %s, %d kB: ", chip->vendor, chip->name, chip->total_size);
		if (!chip->probe && !force) {
			msg_gdbg("failed! flashrom has no probe function for this flash chip.\n");
			continue;
		}

		/* Start filling in the dynamic data. */
		flash->chip = calloc(1, sizeof(*flash->chip));
		if (!flash->chip) {
			msg_gerr("Out of memory!\n");
			exit(1);
		}
		*flash->chip = *chip;
		flash->mst = mst;

		if (map_flash(flash) != 0)
			goto notfound;

		/* We handle a forced match like a real match, we just avoid probing. Note that probe_flash()
		 * is only called with force=1 after normal probing failed.
		 */
		if (force)
			break;

		if (flash->chip->probe(flash) != 1)
			goto notfound;

		/* If this is the first chip found, accept it.
		 * If this is not the first chip found, accept it only if it is
		 * a non-generic match. SFDP and CFI are generic matches.
		 * startchip==0 means this call to probe_flash() is the first
		 * one for this programmer interface (master) and thus no other chip has
		 * been found on this interface.
		 */
		if (startchip == 0 && flash->chip->model_id == SFDP_DEVICE_ID) {
			msg_cinfo("===\n"
				  "SFDP has autodetected a flash chip which is "
				  "not natively supported by flashrom yet.\n");
			if (count_usable_erasers(flash) == 0)
				msg_cinfo("The standard operations read and "
					  "verify should work, but to support "
					  "erase, write and all other "
					  "possible features");
			else
				msg_cinfo("All standard operations (read, "
					  "verify, erase and write) should "
					  "work, but to support all possible "
					  "features");

			msg_cinfo(" we need to add them manually.\n"
				  "You can help us by mailing us the output of the following command to "
				  "flashrom@flashrom.org:\n"
				  "'flashrom -VV [plus the -p/--programmer parameter]'\n"
				  "Thanks for your help!\n"
				  "===\n");
		}

		/* First flash chip detected on this bus. */
		if (startchip == 0)
			break;
		/* Not the first flash chip detected on this bus, but not a generic match either. */
		if ((flash->chip->model_id != GENERIC_DEVICE_ID) && (flash->chip->model_id != SFDP_DEVICE_ID))
			break;
		/* Not the first flash chip detected on this bus, and it's just a generic match. Ignore it. */
notfound:
		unmap_flash(flash);
		free(flash->chip);
		flash->chip = NULL;
	}

	if (!flash->chip)
		return -1;

	/* Fill default layout covering the whole chip. */
	if (flashrom_layout_new(&flash->default_layout) ||
	    flashrom_layout_add_region(flash->default_layout,
			0, flash->chip->total_size * 1024 - 1, "complete flash") ||
	    flashrom_layout_include_region(flash->default_layout, "complete flash"))
	        return -1;

	tmp = flashbuses_to_text(flash->chip->bustype);
	msg_cinfo("%s %s flash chip \"%s\" (%d kB, %s) ", force ? "Assuming" : "Found",
		  flash->chip->vendor, flash->chip->name, flash->chip->total_size, tmp);
	free(tmp);
#if CONFIG_INTERNAL == 1
	if (programmer->map_flash_region == physmap)
		msg_cinfo("mapped at physical address 0x%0*" PRIxPTR ".\n",
			  PRIxPTR_WIDTH, flash->physical_memory);
	else
#endif
		msg_cinfo("on %s.\n", programmer->name);

	/* Flash registers may more likely not be mapped if the chip was forced.
	 * Lock info may be stored in registers, so avoid lock info printing. */
	if (!force)
		if (flash->chip->printlock)
			flash->chip->printlock(flash);

	/* Get out of the way for later runs. */
	unmap_flash(flash);

	/* Return position of matching chip. */
	return chip - flashchips;
}

int read_buf_from_file(unsigned char *buf, unsigned long size,
		       const char *filename)
{
#ifdef __LIBPAYLOAD__
	msg_gerr("Error: No file I/O support in libpayload\n");
	return 1;
#else
	int ret = 0;

	FILE *image;
	if (!strcmp(filename, "-"))
		image = fdopen(fileno(stdin), "rb");
	else
		image = fopen(filename, "rb");
	if (image == NULL) {
		msg_gerr("Error: opening file \"%s\" failed: %s\n", filename, strerror(errno));
		return 1;
	}

	struct stat image_stat;
	if (fstat(fileno(image), &image_stat) != 0) {
		msg_gerr("Error: getting metadata of file \"%s\" failed: %s\n", filename, strerror(errno));
		ret = 1;
		goto out;
	}
	if ((image_stat.st_size != (intmax_t)size) && strcmp(filename, "-")) {
		msg_gerr("Error: Image size (%jd B) doesn't match the expected size (%lu B)!\n",
			 (intmax_t)image_stat.st_size, size);
		ret = 1;
		goto out;
	}

	unsigned long numbytes = fread(buf, 1, size, image);
	if (numbytes != size) {
		msg_gerr("Error: Failed to read complete file. Got %ld bytes, "
			 "wanted %ld!\n", numbytes, size);
		ret = 1;
	}
out:
	(void)fclose(image);
	return ret;
#endif
}

/**
 * @brief Reads content to buffer from one or more files.
 *
 * Reads content to supplied buffer from files. If a filename is specified for
 * individual regions using the partial read syntax ('-i <region>[:<filename>]')
 * then this will read file data into the corresponding region in the
 * supplied buffer.
 *
 * @param flashctx Flash context to be used.
 * @param buf      Chip-sized buffer to write data to
 * @return 0 on success
 */
int read_buf_from_include_args(const struct flashctx *const flash,
				      unsigned char *buf)
{
	const struct flashrom_layout *const layout = get_layout(flash);
	const struct romentry *entry = NULL;

	/*
	 * Content will be read from -i args, so they must not overlap since
	 * we need to know exactly what content to write to the ROM.
	 */
	if (included_regions_overlap(layout)) {
		msg_gerr("Error: Included regions must not overlap when writing.\n");
		return 1;
	}

	while ((entry = layout_next_included(layout, entry))) {
		if (!entry->file)
			continue;
		if (read_buf_from_file(buf + entry->start,
				       entry->end - entry->start + 1, entry->file))
			return 1;
	}
	return 0;
}

/**
 * @brief Writes passed data buffer into a file
 *
 * @param buf      Buffer with data to write
 * @param size     Size of buffer
 * @param filename File path to write to
 * @return 0 on success
 */
int write_buf_to_file(const unsigned char *buf, unsigned long size, const char *filename)
{
#ifdef __LIBPAYLOAD__
	msg_gerr("Error: No file I/O support in libpayload\n");
	return 1;
#else
	FILE *image;
	int ret = 0;

	if (!filename) {
		msg_gerr("No filename specified.\n");
		return 1;
	}
	if ((image = fopen(filename, "wb")) == NULL) {
		msg_gerr("Error: opening file \"%s\" failed: %s\n", filename, strerror(errno));
		return 1;
	}

	unsigned long numbytes = fwrite(buf, 1, size, image);
	if (numbytes != size) {
		msg_gerr("Error: file %s could not be written completely.\n", filename);
		ret = 1;
		goto out;
	}
	if (fflush(image)) {
		msg_gerr("Error: flushing file \"%s\" failed: %s\n", filename, strerror(errno));
		ret = 1;
	}
	// Try to fsync() only regular files and if that function is available at all (e.g. not on MinGW).
#if defined(_POSIX_FSYNC) && (_POSIX_FSYNC != -1)
	struct stat image_stat;
	if (fstat(fileno(image), &image_stat) != 0) {
		msg_gerr("Error: getting metadata of file \"%s\" failed: %s\n", filename, strerror(errno));
		ret = 1;
		goto out;
	}
	if (S_ISREG(image_stat.st_mode)) {
		if (fsync(fileno(image))) {
			msg_gerr("Error: fsyncing file \"%s\" failed: %s\n", filename, strerror(errno));
			ret = 1;
		}
	}
#endif
out:
	if (fclose(image)) {
		msg_gerr("Error: closing file \"%s\" failed: %s\n", filename, strerror(errno));
		ret = 1;
	}
	return ret;
#endif
}

/**
 * @brief Writes content from buffer to one or more files.
 *
 * Writes content from supplied buffer to files. If a filename is specified for
 * individual regions using the partial read syntax ('-i <region>[:<filename>]')
 * then this will write files using data from the corresponding region in the
 * supplied buffer.
 *
 * @param flashctx Flash context to be used.
 * @param buf      Chip-sized buffer to read data from
 * @return 0 on success
 */
int write_buf_to_include_args(const struct flashctx *const flash,
				     unsigned char *buf)
{
	const struct flashrom_layout *const layout = get_layout(flash);
	const struct romentry *entry = NULL;

	while ((entry = layout_next_included(layout, entry))) {
		if (!entry->file)
			continue;
		if (write_buf_to_file(buf + entry->start,
				      entry->end - entry->start + 1, entry->file))
			return 1;
	}

	return 0;
}

/**
 * @brief Reads the included layout regions into a buffer.
 *
 * If there is no layout set in the given flash context, the whole chip will
 * be read.
 *
 * @param flashctx Flash context to be used.
 * @param buffer   Buffer of full chip size to read into.
 * @return 0 on success,
 *	   1 if any read fails.
 */
static int read_by_layout(struct flashctx *const flashctx, uint8_t *const buffer)
{
	const struct flashrom_layout *const layout = get_layout(flashctx);
	const struct romentry *entry = NULL;

	while ((entry = layout_next_included(layout, entry))) {
		const chipoff_t region_start	= entry->start;
		const chipsize_t region_len	= entry->end - entry->start + 1;

		if (flashctx->chip->read(flashctx, buffer + region_start, region_start, region_len))
			return 1;
	}
	return 0;
}

/* Even if an error is found, the function will keep going and check the rest. */
static int selfcheck_eraseblocks(const struct flashchip *chip)
{
	int i, j, k;
	int ret = 0;
	unsigned int prev_eraseblock_count = chip->total_size * 1024;

	for (k = 0; k < NUM_ERASEFUNCTIONS; k++) {
		unsigned int done = 0;
		struct block_eraser eraser = chip->block_erasers[k];
		unsigned int curr_eraseblock_count = 0;

		for (i = 0; i < NUM_ERASEREGIONS; i++) {
			/* Blocks with zero size are bugs in flashchips.c. */
			if (eraser.eraseblocks[i].count &&
			    !eraser.eraseblocks[i].size) {
				msg_gerr("ERROR: Flash chip %s erase function "
					"%i region %i has size 0. Please report"
					" a bug at flashrom@flashrom.org\n",
					chip->name, k, i);
				ret = 1;
			}
			/* Blocks with zero count are bugs in flashchips.c. */
			if (!eraser.eraseblocks[i].count &&
			    eraser.eraseblocks[i].size) {
				msg_gerr("ERROR: Flash chip %s erase function "
					"%i region %i has count 0. Please report"
					" a bug at flashrom@flashrom.org\n",
					chip->name, k, i);
				ret = 1;
			}
			done += eraser.eraseblocks[i].count *
				eraser.eraseblocks[i].size;
			curr_eraseblock_count += eraser.eraseblocks[i].count;
		}
		/* Empty eraseblock definition with erase function.  */
		if (!done && eraser.block_erase)
			msg_gspew("Strange: Empty eraseblock definition with "
				  "non-empty erase function. Not an error.\n");
		if (!done)
			continue;
		if (done != chip->total_size * 1024) {
			msg_gerr("ERROR: Flash chip %s erase function %i "
				"region walking resulted in 0x%06x bytes total,"
				" expected 0x%06x bytes. Please report a bug at"
				" flashrom@flashrom.org\n", chip->name, k,
				done, chip->total_size * 1024);
			ret = 1;
		}
		if (!eraser.block_erase)
			continue;
		/* Check if there are identical erase functions for different
		 * layouts. That would imply "magic" erase functions. The
		 * easiest way to check this is with function pointers.
		 */
		for (j = k + 1; j < NUM_ERASEFUNCTIONS; j++) {
			if (eraser.block_erase ==
			    chip->block_erasers[j].block_erase) {
				msg_gerr("ERROR: Flash chip %s erase function "
					"%i and %i are identical. Please report"
					" a bug at flashrom@flashrom.org\n",
					chip->name, k, j);
				ret = 1;
			}
		}
		if(curr_eraseblock_count > prev_eraseblock_count)
		{
			msg_gerr("ERROR: Flash chip %s erase function %i is not "
					"in order. Please report a bug at flashrom@flashrom.org\n",
					chip->name, k);
			ret = 1;
		}
		prev_eraseblock_count = curr_eraseblock_count;
	}
	return ret;
}

typedef int (*erasefn_t)(struct flashctx *, unsigned int addr, unsigned int len);
/**
 * @private
 *
 * For read-erase-write, `curcontents` and `newcontents` shall point
 * to buffers of the chip's size. Both are supposed to be prefilled
 * with at least the included layout regions of the current flash
 * contents (`curcontents`) and the data to be written to the flash
 * (`newcontents`).
 *
 * For erase, `curcontents` and `newcontents` shall be NULL-pointers.
 *
 * The `chipoff_t` values are used internally by `walk_by_layout()`.
 */
struct walk_info {
	uint8_t *curcontents;
	const uint8_t *newcontents;
	chipoff_t region_start;
	chipoff_t region_end;
	chipoff_t erase_start;
	chipoff_t erase_end;
};
/* returns 0 on success, 1 to retry with another erase function, 2 for immediate abort */
typedef int (*per_blockfn_t)(struct flashctx *, const struct walk_info *, erasefn_t);

static int walk_eraseblocks(struct flashctx *const flashctx,
			    struct walk_info *const info,
			    const size_t erasefunction, const per_blockfn_t per_blockfn)
{
	int ret;
	size_t i, j;
	bool first = true;
	struct block_eraser *const eraser = &flashctx->chip->block_erasers[erasefunction];

	info->erase_start = 0;
	for (i = 0; i < NUM_ERASEREGIONS; ++i) {
		/* count==0 for all automatically initialized array
		   members so the loop below won't be executed for them. */
		for (j = 0; j < eraser->eraseblocks[i].count; ++j, info->erase_start = info->erase_end + 1) {
			info->erase_end = info->erase_start + eraser->eraseblocks[i].size - 1;

			/* Skip any eraseblock that is completely outside the current region. */
			if (info->erase_end < info->region_start)
				continue;
			if (info->region_end < info->erase_start)
				break;

			/* Print this for every block except the first one. */
			if (first)
				first = false;
			else
				msg_cdbg(", ");
			msg_cdbg("0x%06x-0x%06x:", info->erase_start, info->erase_end);

			ret = per_blockfn(flashctx, info, eraser->block_erase);
			if (ret)
				return ret;
		}
		if (info->region_end < info->erase_start)
			break;
	}
	msg_cdbg("\n");
	return 0;
}

static int walk_by_layout(struct flashctx *const flashctx, struct walk_info *const info,
			  const per_blockfn_t per_blockfn)
{
	const struct flashrom_layout *const layout = get_layout(flashctx);
	const struct romentry *entry = NULL;

	all_skipped = true;
	msg_cinfo("Erasing and writing flash chip... ");

	while ((entry = layout_next_included(layout, entry))) {
		info->region_start = entry->start;
		info->region_end   = entry->end;

		size_t j;
		int error = 1; /* retry as long as it's 1 */
		for (j = 0; j < NUM_ERASEFUNCTIONS; ++j) {
			if (j != 0)
				msg_cinfo("Looking for another erase function.\n");
			msg_cdbg("Trying erase function %zi... ", j);
			if (check_block_eraser(flashctx, j, 1))
				continue;

			error = walk_eraseblocks(flashctx, info, j, per_blockfn);
			if (error != 1)
				break;

			if (info->curcontents) {
				msg_cinfo("Reading current flash chip contents... ");
				if (read_by_layout(flashctx, info->curcontents)) {
					/* Now we are truly screwed. Read failed as well. */
					msg_cerr("Can't read anymore! Aborting.\n");
					/* We have no idea about the flash chip contents, so
					   retrying with another erase function is pointless. */
					error = 2;
					break;
				}
				msg_cinfo("done. ");
			}
		}
		if (error == 1)
			msg_cinfo("No usable erase functions left.\n");
		if (error) {
			msg_cerr("FAILED!\n");
			return 1;
		}
	}
	if (all_skipped)
		msg_cinfo("\nWarning: Chip content is identical to the requested image.\n");
	msg_cinfo("Erase/write done.\n");
	return 0;
}

static int erase_block(struct flashctx *const flashctx,
		       const struct walk_info *const info, const erasefn_t erasefn)
{
	const unsigned int erase_len = info->erase_end + 1 - info->erase_start;
	const bool region_unaligned = info->region_start > info->erase_start ||
				      info->erase_end > info->region_end;
	uint8_t *backup_contents = NULL, *erased_contents = NULL;
	int ret = 2;

	/*
	 * If the region is not erase-block aligned, merge current flash con-
	 * tents into a new buffer `backup_contents`.
	 */
	if (region_unaligned) {
		backup_contents = malloc(erase_len);
		erased_contents = malloc(erase_len);
		if (!backup_contents || !erased_contents) {
			msg_cerr("Out of memory!\n");
			ret = 1;
			goto _free_ret;
		}
		memset(backup_contents, ERASED_VALUE(flashctx), erase_len);
		memset(erased_contents, ERASED_VALUE(flashctx), erase_len);

		msg_cdbg("R");
		/* Merge data preceding the current region. */
		if (info->region_start > info->erase_start) {
			const chipoff_t start	= info->erase_start;
			const chipsize_t len	= info->region_start - info->erase_start;
			if (flashctx->chip->read(flashctx, backup_contents, start, len)) {
				msg_cerr("Can't read! Aborting.\n");
				goto _free_ret;
			}
		}
		/* Merge data following the current region. */
		if (info->erase_end > info->region_end) {
			const chipoff_t start     = info->region_end + 1;
			const chipoff_t rel_start = start - info->erase_start; /* within this erase block */
			const chipsize_t len      = info->erase_end - info->region_end;
			if (flashctx->chip->read(flashctx, backup_contents + rel_start, start, len)) {
				msg_cerr("Can't read! Aborting.\n");
				goto _free_ret;
			}
		}
	}

	ret = 1;
	all_skipped = false;

	msg_cdbg("E");
	if (erasefn(flashctx, info->erase_start, erase_len))
		goto _free_ret;
	if (check_erased_range(flashctx, info->erase_start, erase_len)) {
		msg_cerr("ERASE FAILED!\n");
		goto _free_ret;
	}

	if (region_unaligned) {
		unsigned int starthere = 0, lenhere = 0, writecount = 0;
		/* get_next_write() sets starthere to a new value after the call. */
		while ((lenhere = get_next_write(erased_contents + starthere, backup_contents + starthere,
						 erase_len - starthere, &starthere, flashctx->chip->gran))) {
			if (!writecount++)
				msg_cdbg("W");
			/* Needs the partial write function signature. */
			if (flashctx->chip->write(flashctx, backup_contents + starthere,
						  info->erase_start + starthere, lenhere))
				goto _free_ret;
			starthere += lenhere;
		}
	}

	ret = 0;

_free_ret:
	free(erased_contents);
	free(backup_contents);
	return ret;
}

/**
 * @brief Erases the included layout regions.
 *
 * If there is no layout set in the given flash context, the whole chip will
 * be erased.
 *
 * @param flashctx Flash context to be used.
 * @return 0 on success,
 *	   1 if all available erase functions failed.
 */
static int erase_by_layout(struct flashctx *const flashctx)
{
	struct walk_info info = { 0 };
	return walk_by_layout(flashctx, &info, &erase_block);
}

static int read_erase_write_block(struct flashctx *const flashctx,
				  const struct walk_info *const info, const erasefn_t erasefn)
{
	const chipsize_t erase_len = info->erase_end + 1 - info->erase_start;
	const bool region_unaligned = info->region_start > info->erase_start ||
				      info->erase_end > info->region_end;
	const uint8_t *newcontents = NULL;
	int ret = 2;

	/*
	 * If the region is not erase-block aligned, merge current flash con-
	 * tents into `info->curcontents` and a new buffer `newc`. The former
	 * is necessary since we have no guarantee that the full erase block
	 * was already read into `info->curcontents`. For the latter a new
	 * buffer is used since `info->newcontents` might contain data for
	 * other unaligned regions that touch this erase block too.
	 */
	if (region_unaligned) {
		msg_cdbg("R");
		uint8_t *const newc = malloc(erase_len);
		if (!newc) {
			msg_cerr("Out of memory!\n");
			return 1;
		}
		memcpy(newc, info->newcontents + info->erase_start, erase_len);

		/* Merge data preceding the current region. */
		if (info->region_start > info->erase_start) {
			const chipoff_t start	= info->erase_start;
			const chipsize_t len	= info->region_start - info->erase_start;
			if (flashctx->chip->read(flashctx, newc, start, len)) {
				msg_cerr("Can't read! Aborting.\n");
				goto _free_ret;
			}
			memcpy(info->curcontents + start, newc, len);
		}
		/* Merge data following the current region. */
		if (info->erase_end > info->region_end) {
			const chipoff_t start     = info->region_end + 1;
			const chipoff_t rel_start = start - info->erase_start; /* within this erase block */
			const chipsize_t len      = info->erase_end - info->region_end;
			if (flashctx->chip->read(flashctx, newc + rel_start, start, len)) {
				msg_cerr("Can't read! Aborting.\n");
				goto _free_ret;
			}
			memcpy(info->curcontents + start, newc + rel_start, len);
		}

		newcontents = newc;
	} else {
		newcontents = info->newcontents + info->erase_start;
	}

	ret = 1;
	bool skipped = true;
	uint8_t *const curcontents = info->curcontents + info->erase_start;
	const uint8_t erased_value = ERASED_VALUE(flashctx);
	if (!(flashctx->chip->feature_bits & FEATURE_NO_ERASE) &&
			need_erase(curcontents, newcontents, erase_len, flashctx->chip->gran, erased_value)) {
		if (erase_block(flashctx, info, erasefn))
			goto _free_ret;
		/* Erase was successful. Adjust curcontents. */
		memset(curcontents, erased_value, erase_len);
		skipped = false;
	}

	unsigned int starthere = 0, lenhere = 0, writecount = 0;
	/* get_next_write() sets starthere to a new value after the call. */
	while ((lenhere = get_next_write(curcontents + starthere, newcontents + starthere,
					 erase_len - starthere, &starthere, flashctx->chip->gran))) {
		if (!writecount++)
			msg_cdbg("W");
		/* Needs the partial write function signature. */
		if (flashctx->chip->write(flashctx, newcontents + starthere,
					  info->erase_start + starthere, lenhere))
			goto _free_ret;
		starthere += lenhere;
		skipped = false;
	}
	if (skipped)
		msg_cdbg("S");
	else
		all_skipped = false;

	/* Update curcontents, other regions with overlapping erase blocks
	   might rely on this. */
	memcpy(curcontents, newcontents, erase_len);
	ret = 0;

_free_ret:
	if (region_unaligned)
		free((void *)newcontents);
	return ret;
}

/**
 * @brief Writes the included layout regions from a given image.
 *
 * If there is no layout set in the given flash context, the whole image
 * will be written.
 *
 * @param flashctx    Flash context to be used.
 * @param curcontents A buffer of full chip size with current chip contents of included regions.
 * @param newcontents The new image to be written.
 * @return 0 on success,
 *	   1 if anything has gone wrong.
 */
static int write_by_layout(struct flashctx *const flashctx,
			   void *const curcontents, const void *const newcontents)
{
	struct walk_info info;
	info.curcontents = curcontents;
	info.newcontents = newcontents;
	return walk_by_layout(flashctx, &info, read_erase_write_block);
}

/**
 * @brief Compares the included layout regions with content from a buffer.
 *
 * If there is no layout set in the given flash context, the whole chip's
 * contents will be compared.
 *
 * @param flashctx    Flash context to be used.
 * @param layout      Flash layout information.
 * @param curcontents A buffer of full chip size to read current chip contents into.
 * @param newcontents The new image to compare to.
 * @return 0 on success,
 *	   1 if reading failed,
 *	   3 if the contents don't match.
 */
static int verify_by_layout(
		struct flashctx *const flashctx,
		const struct flashrom_layout *const layout,
		void *const curcontents, const uint8_t *const newcontents)
{
	const struct romentry *entry = NULL;

	while ((entry = layout_next_included(layout, entry))) {
		const chipoff_t region_start	= entry->start;
		const chipsize_t region_len	= entry->end - entry->start + 1;

		if (flashctx->chip->read(flashctx, curcontents + region_start, region_start, region_len))
			return 1;
		if (compare_range(newcontents + region_start, curcontents + region_start,
				  region_start, region_len))
			return 3;
	}
	return 0;
}

static void nonfatal_help_message(void)
{
	msg_gerr("Good, writing to the flash chip apparently didn't do anything.\n");
#if CONFIG_INTERNAL == 1
	if (programmer == &programmer_internal)
		msg_gerr("This means we have to add special support for your board, programmer or flash\n"
			 "chip. Please report this to the mailing list at flashrom@flashrom.org or on\n"
			 "IRC (see https://www.flashrom.org/Contact for details), thanks!\n"
			 "-------------------------------------------------------------------------------\n"
			 "You may now reboot or simply leave the machine running.\n");
	else
#endif
		msg_gerr("Please check the connections (especially those to write protection pins) between\n"
			 "the programmer and the flash chip. If you think the error is caused by flashrom\n"
			 "please report this to the mailing list at flashrom@flashrom.org or on IRC (see\n"
			 "https://www.flashrom.org/Contact for details), thanks!\n");
}

void emergency_help_message(void)
{
	msg_gerr("Your flash chip is in an unknown state.\n");
#if CONFIG_INTERNAL == 1
	if (programmer == &programmer_internal)
		msg_gerr("Get help on IRC (see https://www.flashrom.org/Contact) or mail\n"
			"flashrom@flashrom.org with the subject \"FAILED: <your board name>\"!"
			"-------------------------------------------------------------------------------\n"
			"DO NOT REBOOT OR POWEROFF!\n");
	else
#endif
		msg_gerr("Please report this to the mailing list at flashrom@flashrom.org or\n"
			 "on IRC (see https://www.flashrom.org/Contact for details), thanks!\n");
}

void list_programmers_linebreak(int startcol, int cols, int paren)
{
	const char *pname;
	int pnamelen;
	int remaining = 0, firstline = 1;
	size_t p;
	int i;

	for (p = 0; p < programmer_table_size; p++) {
		pname = programmer_table[p]->name;
		pnamelen = strlen(pname);
		if (remaining - pnamelen - 2 < 0) {
			if (firstline)
				firstline = 0;
			else
				msg_ginfo("\n");
			for (i = 0; i < startcol; i++)
				msg_ginfo(" ");
			remaining = cols - startcol;
		} else {
			msg_ginfo(" ");
			remaining--;
		}
		if (paren && (p == 0)) {
			msg_ginfo("(");
			remaining--;
		}
		msg_ginfo("%s", pname);
		remaining -= pnamelen;
		if (p < programmer_table_size - 1) {
			msg_ginfo(",");
			remaining--;
		} else {
			if (paren)
				msg_ginfo(")");
		}
	}
}

static void print_sysinfo(void)
{
#if IS_WINDOWS
	SYSTEM_INFO si = { 0 };
	OSVERSIONINFOEX osvi = { 0 };

	msg_ginfo(" on Windows");
	/* Tell Windows which version of the structure we want. */
	osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
	if (GetVersionEx((OSVERSIONINFO*) &osvi))
		msg_ginfo(" %lu.%lu", osvi.dwMajorVersion, osvi.dwMinorVersion);
	else
		msg_ginfo(" unknown version");
	GetSystemInfo(&si);
	switch (si.wProcessorArchitecture) {
	case PROCESSOR_ARCHITECTURE_AMD64:
		msg_ginfo(" (x86_64)");
		break;
	case PROCESSOR_ARCHITECTURE_INTEL:
		msg_ginfo(" (x86)");
		break;
	default:
		msg_ginfo(" (unknown arch)");
		break;
	}
#elif HAVE_UTSNAME == 1
	struct utsname osinfo;

	uname(&osinfo);
	msg_ginfo(" on %s %s (%s)", osinfo.sysname, osinfo.release,
		  osinfo.machine);
#else
	msg_ginfo(" on unknown machine");
#endif
}

void print_buildinfo(void)
{
	msg_gdbg("flashrom was built with");
#ifdef __clang__
	msg_gdbg(" LLVM Clang");
#ifdef __clang_version__
	msg_gdbg(" %s,", __clang_version__);
#else
	msg_gdbg(" unknown version (before r102686),");
#endif
#elif defined(__GNUC__)
	msg_gdbg(" GCC");
#ifdef __VERSION__
	msg_gdbg(" %s,", __VERSION__);
#else
	msg_gdbg(" unknown version,");
#endif
#else
	msg_gdbg(" unknown compiler,");
#endif
#if defined (__FLASHROM_LITTLE_ENDIAN__)
	msg_gdbg(" little endian");
#elif defined (__FLASHROM_BIG_ENDIAN__)
	msg_gdbg(" big endian");
#else
#error Endianness could not be determined
#endif
	msg_gdbg("\n");
}

void print_version(void)
{
	msg_ginfo("flashrom %s", flashrom_version);
	print_sysinfo();
	msg_ginfo("\n");
}

void print_banner(void)
{
	msg_ginfo("flashrom is free software, get the source code at "
		  "https://flashrom.org\n");
	msg_ginfo("\n");
}

int selfcheck(void)
{
	unsigned int i;
	int ret = 0;

	for (i = 0; i < programmer_table_size; i++) {
		const struct programmer_entry *const p = programmer_table[i];
		if (p == NULL) {
			msg_gerr("Programmer with index %d is NULL instead of a valid pointer!\n", i);
			ret = 1;
			continue;
		}
		if (p->name == NULL) {
			msg_gerr("All programmers need a valid name, but the one with index %d does not!\n", i);
			ret = 1;
			/* This might hide other problems with this programmer, but allows for better error
			 * messages below without jumping through hoops. */
			continue;
		}
		switch (p->type) {
		case USB:
		case PCI:
		case OTHER:
			if (p->devs.note == NULL) {
				if (strcmp("internal", p->name) == 0)
					break; /* This one has its device list stored separately. */
				msg_gerr("Programmer %s has neither a device list nor a textual description!\n",
					 p->name);
				ret = 1;
			}
			break;
		default:
			msg_gerr("Programmer %s does not have a valid type set!\n", p->name);
			ret = 1;
			break;
		}
		if (p->init == NULL) {
			msg_gerr("Programmer %s does not have a valid init function!\n", p->name);
			ret = 1;
		}
		if (p->delay == NULL) {
			msg_gerr("Programmer %s does not have a valid delay function!\n", p->name);
			ret = 1;
		}
		if (p->map_flash_region == NULL) {
			msg_gerr("Programmer %s does not have a valid map_flash_region function!\n", p->name);
			ret = 1;
		}
		if (p->unmap_flash_region == NULL) {
			msg_gerr("Programmer %s does not have a valid unmap_flash_region function!\n", p->name);
			ret = 1;
		}
	}

	/* It would be favorable if we could check for the correct layout (especially termination) of various
	 * constant arrays: flashchips, chipset_enables, board_matches, boards_known, laptops_known.
	 * They are all defined as externs in this compilation unit so we don't know their sizes which vary
	 * depending on compiler flags, e.g. the target architecture, and can sometimes be 0.
	 * For 'flashchips' we export the size explicitly to work around this and to be able to implement the
	 * checks below. */
	if (flashchips_size <= 1 || flashchips[flashchips_size - 1].name != NULL) {
		msg_gerr("Flashchips table miscompilation!\n");
		ret = 1;
	} else {
		for (i = 0; i < flashchips_size - 1; i++) {
			const struct flashchip *chip = &flashchips[i];
			if (chip->vendor == NULL || chip->name == NULL || chip->bustype == BUS_NONE) {
				ret = 1;
				msg_gerr("ERROR: Some field of flash chip #%d (%s) is misconfigured.\n"
					 "Please report a bug at flashrom@flashrom.org\n", i,
					 chip->name == NULL ? "unnamed" : chip->name);
			}
			if (selfcheck_eraseblocks(chip)) {
				ret = 1;
			}
		}
	}

#if CONFIG_INTERNAL == 1
	ret |= selfcheck_board_enables();
#endif

	/* TODO: implement similar sanity checks for other arrays where deemed necessary. */
	return ret;
}

/* FIXME: This function signature needs to be improved once prepare_flash_access()
 * has a better function signature.
 */
static int chip_safety_check(const struct flashctx *flash, int force,
			     int read_it, int write_it, int erase_it, int verify_it)
{
	const struct flashchip *chip = flash->chip;

	if (!programmer_may_write && (write_it || erase_it)) {
		msg_perr("Write/erase is not working yet on your programmer in "
			 "its current configuration.\n");
		/* --force is the wrong approach, but it's the best we can do
		 * until the generic programmer parameter parser is merged.
		 */
		if (!force)
			return 1;
		msg_cerr("Continuing anyway.\n");
	}

	if (read_it || erase_it || write_it || verify_it) {
		/* Everything needs read. */
		if (chip->tested.read == BAD) {
			msg_cerr("Read is not working on this chip. ");
			if (!force)
				return 1;
			msg_cerr("Continuing anyway.\n");
		}
		if (!chip->read) {
			msg_cerr("flashrom has no read function for this "
				 "flash chip.\n");
			return 1;
		}
	}
	if (erase_it || write_it) {
		/* Write needs erase. */
		if (chip->tested.erase == NA) {
			msg_cerr("Erase is not possible on this chip.\n");
			return 1;
		}
		if (chip->tested.erase == BAD) {
			msg_cerr("Erase is not working on this chip. ");
			if (!force)
				return 1;
			msg_cerr("Continuing anyway.\n");
		}
		if(count_usable_erasers(flash) == 0) {
			msg_cerr("flashrom has no erase function for this "
				 "flash chip.\n");
			return 1;
		}
	}
	if (write_it) {
		if (chip->tested.write == NA) {
			msg_cerr("Write is not possible on this chip.\n");
			return 1;
		}
		if (chip->tested.write == BAD) {
			msg_cerr("Write is not working on this chip. ");
			if (!force)
				return 1;
			msg_cerr("Continuing anyway.\n");
		}
		if (!chip->write) {
			msg_cerr("flashrom has no write function for this "
				 "flash chip.\n");
			return 1;
		}
	}
	return 0;
}

int prepare_flash_access(struct flashctx *const flash,
			 const bool read_it, const bool write_it,
			 const bool erase_it, const bool verify_it)
{
	if (chip_safety_check(flash, flash->flags.force, read_it, write_it, erase_it, verify_it)) {
		msg_cerr("Aborting.\n");
		return 1;
	}

	if (layout_sanity_checks(flash)) {
		msg_cerr("Requested regions can not be handled. Aborting.\n");
		return 1;
	}

	if (map_flash(flash) != 0)
		return 1;

	/* Initialize chip_restore_fn_count before chip unlock calls. */
	flash->chip_restore_fn_count = 0;

	/* Given the existence of read locks, we want to unlock for read,
	   erase and write. */
	if (flash->chip->unlock)
		flash->chip->unlock(flash);

	flash->address_high_byte = -1;
	flash->in_4ba_mode = false;

	/* Be careful about 4BA chips and broken masters */
	if (flash->chip->total_size > 16 * 1024 && spi_master_no_4ba_modes(flash)) {
		/* If we can't use native instructions, bail out */
		if ((flash->chip->feature_bits & FEATURE_4BA_NATIVE) != FEATURE_4BA_NATIVE
		    || !spi_master_4ba(flash)) {
			msg_cerr("Programmer doesn't support this chip. Aborting.\n");
			return 1;
		}
	}

	/* Enable/disable 4-byte addressing mode if flash chip supports it */
	if (flash->chip->feature_bits & (FEATURE_4BA_ENTER | FEATURE_4BA_ENTER_WREN | FEATURE_4BA_ENTER_EAR7)) {
		int ret;
		if (spi_master_4ba(flash))
			ret = spi_enter_4ba(flash);
		else
			ret = spi_exit_4ba(flash);
		if (ret) {
			msg_cerr("Failed to set correct 4BA mode! Aborting.\n");
			return 1;
		}
	}

	return 0;
}

void finalize_flash_access(struct flashctx *const flash)
{
	deregister_chip_restore(flash);
	unmap_flash(flash);
}

int flashrom_flash_erase(struct flashctx *const flashctx)
{
	if (prepare_flash_access(flashctx, false, false, true, false))
		return 1;

	const int ret = erase_by_layout(flashctx);

	finalize_flash_access(flashctx);

	return ret;
}

int flashrom_image_read(struct flashctx *const flashctx, void *const buffer, const size_t buffer_len)
{
	const size_t flash_size = flashctx->chip->total_size * 1024;

	if (flash_size > buffer_len)
		return 2;

	if (prepare_flash_access(flashctx, true, false, false, false))
		return 1;

	msg_cinfo("Reading flash... ");

	int ret = 1;
	if (read_by_layout(flashctx, buffer)) {
		msg_cerr("Read operation failed!\n");
		msg_cinfo("FAILED.\n");
		goto _finalize_ret;
	}
	msg_cinfo("done.\n");
	ret = 0;

_finalize_ret:
	finalize_flash_access(flashctx);
	return ret;
}

static void combine_image_by_layout(const struct flashctx *const flashctx,
				    uint8_t *const newcontents, const uint8_t *const oldcontents)
{
	const struct flashrom_layout *const layout = get_layout(flashctx);
	const struct romentry *included;
	chipoff_t start = 0;

	while ((included = layout_next_included_region(layout, start))) {
		if (included->start > start) {
			/* copy everything up to the start of this included region */
			memcpy(newcontents + start, oldcontents + start, included->start - start);
		}
		/* skip this included region */
		start = included->end + 1;
		if (start == 0)
			return;
	}

	/* copy the rest of the chip */
	const chipsize_t copy_len = flashctx->chip->total_size * 1024 - start;
	memcpy(newcontents + start, oldcontents + start, copy_len);
}

int flashrom_image_write(struct flashctx *const flashctx, void *const buffer, const size_t buffer_len,
                         const void *const refbuffer)
{
	const size_t flash_size = flashctx->chip->total_size * 1024;
	const bool verify_all = flashctx->flags.verify_whole_chip;
	const bool verify = flashctx->flags.verify_after_write;
	const struct flashrom_layout *const verify_layout =
		verify_all ? get_default_layout(flashctx) : get_layout(flashctx);

	if (buffer_len != flash_size)
		return 4;

	int ret = 1;

	uint8_t *const newcontents = buffer;
	const uint8_t *const refcontents = refbuffer;
	uint8_t *const curcontents = malloc(flash_size);
	uint8_t *oldcontents = NULL;
	if (verify_all)
		oldcontents = malloc(flash_size);
	if (!curcontents || (verify_all && !oldcontents)) {
		msg_gerr("Out of memory!\n");
		goto _free_ret;
	}

#if CONFIG_INTERNAL == 1
	if (programmer == &programmer_internal && cb_check_image(newcontents, flash_size) < 0) {
		if (flashctx->flags.force_boardmismatch) {
			msg_pinfo("Proceeding anyway because user forced us to.\n");
		} else {
			msg_perr("Aborting. You can override this with "
				 "-p internal:boardmismatch=force.\n");
			goto _free_ret;
		}
	}
#endif

	if (prepare_flash_access(flashctx, false, true, false, verify))
		goto _free_ret;

	/* If given, assume flash chip contains same data as `refcontents`. */
	if (refcontents) {
		msg_cinfo("Assuming old flash chip contents as ref-file...\n");
		memcpy(curcontents, refcontents, flash_size);
		if (oldcontents)
			memcpy(oldcontents, refcontents, flash_size);
	} else {
		/*
		 * Read the whole chip to be able to check whether regions need to be
		 * erased and to give better diagnostics in case write fails.
		 * The alternative is to read only the regions which are to be
		 * preserved, but in that case we might perform unneeded erase which
		 * takes time as well.
		 */
		msg_cinfo("Reading old flash chip contents... ");
		if (verify_all) {
			if (flashctx->chip->read(flashctx, oldcontents, 0, flash_size)) {
				msg_cinfo("FAILED.\n");
				goto _finalize_ret;
			}
			memcpy(curcontents, oldcontents, flash_size);
		} else {
			if (read_by_layout(flashctx, curcontents)) {
				msg_cinfo("FAILED.\n");
				goto _finalize_ret;
			}
		}
		msg_cinfo("done.\n");
	}

	if (write_by_layout(flashctx, curcontents, newcontents)) {
		msg_cerr("Uh oh. Erase/write failed. ");
		ret = 2;
		if (verify_all) {
			msg_cerr("Checking if anything has changed.\n");
			msg_cinfo("Reading current flash chip contents... ");
			if (!flashctx->chip->read(flashctx, curcontents, 0, flash_size)) {
				msg_cinfo("done.\n");
				if (!memcmp(oldcontents, curcontents, flash_size)) {
					nonfatal_help_message();
					goto _finalize_ret;
				}
				msg_cerr("Apparently at least some data has changed.\n");
			} else
				msg_cerr("Can't even read anymore!\n");
			emergency_help_message();
			goto _finalize_ret;
		} else {
			msg_cerr("\n");
		}
		emergency_help_message();
		goto _finalize_ret;
	}

	/* Verify only if we actually changed something. */
	if (verify && !all_skipped) {
		msg_cinfo("Verifying flash... ");

		/* Work around chips which need some time to calm down. */
		programmer_delay(1000*1000);

		if (verify_all)
			combine_image_by_layout(flashctx, newcontents, oldcontents);
		ret = verify_by_layout(flashctx, verify_layout, curcontents, newcontents);
		/* If we tried to write, and verification now fails, we
		   might have an emergency situation. */
		if (ret)
			emergency_help_message();
		else
			msg_cinfo("VERIFIED.\n");
	} else {
		/* We didn't change anything. */
		ret = 0;
	}

_finalize_ret:
	finalize_flash_access(flashctx);
_free_ret:
	free(oldcontents);
	free(curcontents);
	return ret;
}

int flashrom_image_verify(struct flashctx *const flashctx, const void *const buffer, const size_t buffer_len)
{
	const struct flashrom_layout *const layout = get_layout(flashctx);
	const size_t flash_size = flashctx->chip->total_size * 1024;

	if (buffer_len != flash_size)
		return 2;

	const uint8_t *const newcontents = buffer;
	uint8_t *const curcontents = malloc(flash_size);
	if (!curcontents) {
		msg_gerr("Out of memory!\n");
		return 1;
	}

	int ret = 1;

	if (prepare_flash_access(flashctx, false, false, false, true))
		goto _free_ret;

	msg_cinfo("Verifying flash... ");
	ret = verify_by_layout(flashctx, layout, curcontents, newcontents);
	if (!ret)
		msg_cinfo("VERIFIED.\n");

	finalize_flash_access(flashctx);
_free_ret:
	free(curcontents);
	return ret;
}