xref: /openbmc/linux/drivers/mtd/nand/raw/nandsim.c (revision aac28965)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * NAND flash simulator.
4  *
5  * Author: Artem B. Bityuckiy <dedekind@oktetlabs.ru>, <dedekind@infradead.org>
6  *
7  * Copyright (C) 2004 Nokia Corporation
8  *
9  * Note: NS means "NAND Simulator".
10  * Note: Input means input TO flash chip, output means output FROM chip.
11  */
12 
13 #define pr_fmt(fmt)  "[nandsim]" fmt
14 
15 #include <linux/init.h>
16 #include <linux/types.h>
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/vmalloc.h>
20 #include <linux/math64.h>
21 #include <linux/slab.h>
22 #include <linux/errno.h>
23 #include <linux/string.h>
24 #include <linux/mtd/mtd.h>
25 #include <linux/mtd/rawnand.h>
26 #include <linux/mtd/partitions.h>
27 #include <linux/delay.h>
28 #include <linux/list.h>
29 #include <linux/random.h>
30 #include <linux/sched.h>
31 #include <linux/sched/mm.h>
32 #include <linux/fs.h>
33 #include <linux/pagemap.h>
34 #include <linux/seq_file.h>
35 #include <linux/debugfs.h>
36 
37 /* Default simulator parameters values */
38 #if !defined(CONFIG_NANDSIM_FIRST_ID_BYTE)  || \
39     !defined(CONFIG_NANDSIM_SECOND_ID_BYTE) || \
40     !defined(CONFIG_NANDSIM_THIRD_ID_BYTE)  || \
41     !defined(CONFIG_NANDSIM_FOURTH_ID_BYTE)
42 #define CONFIG_NANDSIM_FIRST_ID_BYTE  0x98
43 #define CONFIG_NANDSIM_SECOND_ID_BYTE 0x39
44 #define CONFIG_NANDSIM_THIRD_ID_BYTE  0xFF /* No byte */
45 #define CONFIG_NANDSIM_FOURTH_ID_BYTE 0xFF /* No byte */
46 #endif
47 
48 #ifndef CONFIG_NANDSIM_ACCESS_DELAY
49 #define CONFIG_NANDSIM_ACCESS_DELAY 25
50 #endif
51 #ifndef CONFIG_NANDSIM_PROGRAMM_DELAY
52 #define CONFIG_NANDSIM_PROGRAMM_DELAY 200
53 #endif
54 #ifndef CONFIG_NANDSIM_ERASE_DELAY
55 #define CONFIG_NANDSIM_ERASE_DELAY 2
56 #endif
57 #ifndef CONFIG_NANDSIM_OUTPUT_CYCLE
58 #define CONFIG_NANDSIM_OUTPUT_CYCLE 40
59 #endif
60 #ifndef CONFIG_NANDSIM_INPUT_CYCLE
61 #define CONFIG_NANDSIM_INPUT_CYCLE  50
62 #endif
63 #ifndef CONFIG_NANDSIM_BUS_WIDTH
64 #define CONFIG_NANDSIM_BUS_WIDTH  8
65 #endif
66 #ifndef CONFIG_NANDSIM_DO_DELAYS
67 #define CONFIG_NANDSIM_DO_DELAYS  0
68 #endif
69 #ifndef CONFIG_NANDSIM_LOG
70 #define CONFIG_NANDSIM_LOG        0
71 #endif
72 #ifndef CONFIG_NANDSIM_DBG
73 #define CONFIG_NANDSIM_DBG        0
74 #endif
75 #ifndef CONFIG_NANDSIM_MAX_PARTS
76 #define CONFIG_NANDSIM_MAX_PARTS  32
77 #endif
78 
79 static uint access_delay   = CONFIG_NANDSIM_ACCESS_DELAY;
80 static uint programm_delay = CONFIG_NANDSIM_PROGRAMM_DELAY;
81 static uint erase_delay    = CONFIG_NANDSIM_ERASE_DELAY;
82 static uint output_cycle   = CONFIG_NANDSIM_OUTPUT_CYCLE;
83 static uint input_cycle    = CONFIG_NANDSIM_INPUT_CYCLE;
84 static uint bus_width      = CONFIG_NANDSIM_BUS_WIDTH;
85 static uint do_delays      = CONFIG_NANDSIM_DO_DELAYS;
86 static uint log            = CONFIG_NANDSIM_LOG;
87 static uint dbg            = CONFIG_NANDSIM_DBG;
88 static unsigned long parts[CONFIG_NANDSIM_MAX_PARTS];
89 static unsigned int parts_num;
90 static char *badblocks = NULL;
91 static char *weakblocks = NULL;
92 static char *weakpages = NULL;
93 static unsigned int bitflips = 0;
94 static char *gravepages = NULL;
95 static unsigned int overridesize = 0;
96 static char *cache_file = NULL;
97 static unsigned int bbt;
98 static unsigned int bch;
99 static u_char id_bytes[8] = {
100 	[0] = CONFIG_NANDSIM_FIRST_ID_BYTE,
101 	[1] = CONFIG_NANDSIM_SECOND_ID_BYTE,
102 	[2] = CONFIG_NANDSIM_THIRD_ID_BYTE,
103 	[3] = CONFIG_NANDSIM_FOURTH_ID_BYTE,
104 	[4 ... 7] = 0xFF,
105 };
106 
107 module_param_array(id_bytes, byte, NULL, 0400);
108 module_param_named(first_id_byte, id_bytes[0], byte, 0400);
109 module_param_named(second_id_byte, id_bytes[1], byte, 0400);
110 module_param_named(third_id_byte, id_bytes[2], byte, 0400);
111 module_param_named(fourth_id_byte, id_bytes[3], byte, 0400);
112 module_param(access_delay,   uint, 0400);
113 module_param(programm_delay, uint, 0400);
114 module_param(erase_delay,    uint, 0400);
115 module_param(output_cycle,   uint, 0400);
116 module_param(input_cycle,    uint, 0400);
117 module_param(bus_width,      uint, 0400);
118 module_param(do_delays,      uint, 0400);
119 module_param(log,            uint, 0400);
120 module_param(dbg,            uint, 0400);
121 module_param_array(parts, ulong, &parts_num, 0400);
122 module_param(badblocks,      charp, 0400);
123 module_param(weakblocks,     charp, 0400);
124 module_param(weakpages,      charp, 0400);
125 module_param(bitflips,       uint, 0400);
126 module_param(gravepages,     charp, 0400);
127 module_param(overridesize,   uint, 0400);
128 module_param(cache_file,     charp, 0400);
129 module_param(bbt,	     uint, 0400);
130 module_param(bch,	     uint, 0400);
131 
132 MODULE_PARM_DESC(id_bytes,       "The ID bytes returned by NAND Flash 'read ID' command");
133 MODULE_PARM_DESC(first_id_byte,  "The first byte returned by NAND Flash 'read ID' command (manufacturer ID) (obsolete)");
134 MODULE_PARM_DESC(second_id_byte, "The second byte returned by NAND Flash 'read ID' command (chip ID) (obsolete)");
135 MODULE_PARM_DESC(third_id_byte,  "The third byte returned by NAND Flash 'read ID' command (obsolete)");
136 MODULE_PARM_DESC(fourth_id_byte, "The fourth byte returned by NAND Flash 'read ID' command (obsolete)");
137 MODULE_PARM_DESC(access_delay,   "Initial page access delay (microseconds)");
138 MODULE_PARM_DESC(programm_delay, "Page programm delay (microseconds");
139 MODULE_PARM_DESC(erase_delay,    "Sector erase delay (milliseconds)");
140 MODULE_PARM_DESC(output_cycle,   "Word output (from flash) time (nanoseconds)");
141 MODULE_PARM_DESC(input_cycle,    "Word input (to flash) time (nanoseconds)");
142 MODULE_PARM_DESC(bus_width,      "Chip's bus width (8- or 16-bit)");
143 MODULE_PARM_DESC(do_delays,      "Simulate NAND delays using busy-waits if not zero");
144 MODULE_PARM_DESC(log,            "Perform logging if not zero");
145 MODULE_PARM_DESC(dbg,            "Output debug information if not zero");
146 MODULE_PARM_DESC(parts,          "Partition sizes (in erase blocks) separated by commas");
147 /* Page and erase block positions for the following parameters are independent of any partitions */
148 MODULE_PARM_DESC(badblocks,      "Erase blocks that are initially marked bad, separated by commas");
149 MODULE_PARM_DESC(weakblocks,     "Weak erase blocks [: remaining erase cycles (defaults to 3)]"
150 				 " separated by commas e.g. 113:2 means eb 113"
151 				 " can be erased only twice before failing");
152 MODULE_PARM_DESC(weakpages,      "Weak pages [: maximum writes (defaults to 3)]"
153 				 " separated by commas e.g. 1401:2 means page 1401"
154 				 " can be written only twice before failing");
155 MODULE_PARM_DESC(bitflips,       "Maximum number of random bit flips per page (zero by default)");
156 MODULE_PARM_DESC(gravepages,     "Pages that lose data [: maximum reads (defaults to 3)]"
157 				 " separated by commas e.g. 1401:2 means page 1401"
158 				 " can be read only twice before failing");
159 MODULE_PARM_DESC(overridesize,   "Specifies the NAND Flash size overriding the ID bytes. "
160 				 "The size is specified in erase blocks and as the exponent of a power of two"
161 				 " e.g. 5 means a size of 32 erase blocks");
162 MODULE_PARM_DESC(cache_file,     "File to use to cache nand pages instead of memory");
163 MODULE_PARM_DESC(bbt,		 "0 OOB, 1 BBT with marker in OOB, 2 BBT with marker in data area");
164 MODULE_PARM_DESC(bch,		 "Enable BCH ecc and set how many bits should "
165 				 "be correctable in 512-byte blocks");
166 
167 /* The largest possible page size */
168 #define NS_LARGEST_PAGE_SIZE	4096
169 
170 /* Simulator's output macros (logging, debugging, warning, error) */
171 #define NS_LOG(args...) \
172 	do { if (log) pr_debug(" log: " args); } while(0)
173 #define NS_DBG(args...) \
174 	do { if (dbg) pr_debug(" debug: " args); } while(0)
175 #define NS_WARN(args...) \
176 	do { pr_warn(" warning: " args); } while(0)
177 #define NS_ERR(args...) \
178 	do { pr_err(" error: " args); } while(0)
179 #define NS_INFO(args...) \
180 	do { pr_info(" " args); } while(0)
181 
182 /* Busy-wait delay macros (microseconds, milliseconds) */
183 #define NS_UDELAY(us) \
184         do { if (do_delays) udelay(us); } while(0)
185 #define NS_MDELAY(us) \
186         do { if (do_delays) mdelay(us); } while(0)
187 
188 /* Is the nandsim structure initialized ? */
189 #define NS_IS_INITIALIZED(ns) ((ns)->geom.totsz != 0)
190 
191 /* Good operation completion status */
192 #define NS_STATUS_OK(ns) (NAND_STATUS_READY | (NAND_STATUS_WP * ((ns)->lines.wp == 0)))
193 
194 /* Operation failed completion status */
195 #define NS_STATUS_FAILED(ns) (NAND_STATUS_FAIL | NS_STATUS_OK(ns))
196 
197 /* Calculate the page offset in flash RAM image by (row, column) address */
198 #define NS_RAW_OFFSET(ns) \
199 	(((ns)->regs.row * (ns)->geom.pgszoob) + (ns)->regs.column)
200 
201 /* Calculate the OOB offset in flash RAM image by (row, column) address */
202 #define NS_RAW_OFFSET_OOB(ns) (NS_RAW_OFFSET(ns) + ns->geom.pgsz)
203 
204 /* Calculate the byte shift in the next page to access */
205 #define NS_PAGE_BYTE_SHIFT(ns) ((ns)->regs.column + (ns)->regs.off)
206 
207 /* After a command is input, the simulator goes to one of the following states */
208 #define STATE_CMD_READ0        0x00000001 /* read data from the beginning of page */
209 #define STATE_CMD_READ1        0x00000002 /* read data from the second half of page */
210 #define STATE_CMD_READSTART    0x00000003 /* read data second command (large page devices) */
211 #define STATE_CMD_PAGEPROG     0x00000004 /* start page program */
212 #define STATE_CMD_READOOB      0x00000005 /* read OOB area */
213 #define STATE_CMD_ERASE1       0x00000006 /* sector erase first command */
214 #define STATE_CMD_STATUS       0x00000007 /* read status */
215 #define STATE_CMD_SEQIN        0x00000009 /* sequential data input */
216 #define STATE_CMD_READID       0x0000000A /* read ID */
217 #define STATE_CMD_ERASE2       0x0000000B /* sector erase second command */
218 #define STATE_CMD_RESET        0x0000000C /* reset */
219 #define STATE_CMD_RNDOUT       0x0000000D /* random output command */
220 #define STATE_CMD_RNDOUTSTART  0x0000000E /* random output start command */
221 #define STATE_CMD_MASK         0x0000000F /* command states mask */
222 
223 /* After an address is input, the simulator goes to one of these states */
224 #define STATE_ADDR_PAGE        0x00000010 /* full (row, column) address is accepted */
225 #define STATE_ADDR_SEC         0x00000020 /* sector address was accepted */
226 #define STATE_ADDR_COLUMN      0x00000030 /* column address was accepted */
227 #define STATE_ADDR_ZERO        0x00000040 /* one byte zero address was accepted */
228 #define STATE_ADDR_MASK        0x00000070 /* address states mask */
229 
230 /* During data input/output the simulator is in these states */
231 #define STATE_DATAIN           0x00000100 /* waiting for data input */
232 #define STATE_DATAIN_MASK      0x00000100 /* data input states mask */
233 
234 #define STATE_DATAOUT          0x00001000 /* waiting for page data output */
235 #define STATE_DATAOUT_ID       0x00002000 /* waiting for ID bytes output */
236 #define STATE_DATAOUT_STATUS   0x00003000 /* waiting for status output */
237 #define STATE_DATAOUT_MASK     0x00007000 /* data output states mask */
238 
239 /* Previous operation is done, ready to accept new requests */
240 #define STATE_READY            0x00000000
241 
242 /* This state is used to mark that the next state isn't known yet */
243 #define STATE_UNKNOWN          0x10000000
244 
245 /* Simulator's actions bit masks */
246 #define ACTION_CPY       0x00100000 /* copy page/OOB to the internal buffer */
247 #define ACTION_PRGPAGE   0x00200000 /* program the internal buffer to flash */
248 #define ACTION_SECERASE  0x00300000 /* erase sector */
249 #define ACTION_ZEROOFF   0x00400000 /* don't add any offset to address */
250 #define ACTION_HALFOFF   0x00500000 /* add to address half of page */
251 #define ACTION_OOBOFF    0x00600000 /* add to address OOB offset */
252 #define ACTION_MASK      0x00700000 /* action mask */
253 
254 #define NS_OPER_NUM      13 /* Number of operations supported by the simulator */
255 #define NS_OPER_STATES   6  /* Maximum number of states in operation */
256 
257 #define OPT_ANY          0xFFFFFFFF /* any chip supports this operation */
258 #define OPT_PAGE512      0x00000002 /* 512-byte  page chips */
259 #define OPT_PAGE2048     0x00000008 /* 2048-byte page chips */
260 #define OPT_PAGE512_8BIT 0x00000040 /* 512-byte page chips with 8-bit bus width */
261 #define OPT_PAGE4096     0x00000080 /* 4096-byte page chips */
262 #define OPT_LARGEPAGE    (OPT_PAGE2048 | OPT_PAGE4096) /* 2048 & 4096-byte page chips */
263 #define OPT_SMALLPAGE    (OPT_PAGE512) /* 512-byte page chips */
264 
265 /* Remove action bits from state */
266 #define NS_STATE(x) ((x) & ~ACTION_MASK)
267 
268 /*
269  * Maximum previous states which need to be saved. Currently saving is
270  * only needed for page program operation with preceded read command
271  * (which is only valid for 512-byte pages).
272  */
273 #define NS_MAX_PREVSTATES 1
274 
275 /* Maximum page cache pages needed to read or write a NAND page to the cache_file */
276 #define NS_MAX_HELD_PAGES 16
277 
278 /*
279  * A union to represent flash memory contents and flash buffer.
280  */
281 union ns_mem {
282 	u_char *byte;    /* for byte access */
283 	uint16_t *word;  /* for 16-bit word access */
284 };
285 
286 /*
287  * The structure which describes all the internal simulator data.
288  */
289 struct nandsim {
290 	struct nand_chip chip;
291 	struct nand_controller base;
292 	struct mtd_partition partitions[CONFIG_NANDSIM_MAX_PARTS];
293 	unsigned int nbparts;
294 
295 	uint busw;              /* flash chip bus width (8 or 16) */
296 	u_char ids[8];          /* chip's ID bytes */
297 	uint32_t options;       /* chip's characteristic bits */
298 	uint32_t state;         /* current chip state */
299 	uint32_t nxstate;       /* next expected state */
300 
301 	uint32_t *op;           /* current operation, NULL operations isn't known yet  */
302 	uint32_t pstates[NS_MAX_PREVSTATES]; /* previous states */
303 	uint16_t npstates;      /* number of previous states saved */
304 	uint16_t stateidx;      /* current state index */
305 
306 	/* The simulated NAND flash pages array */
307 	union ns_mem *pages;
308 
309 	/* Slab allocator for nand pages */
310 	struct kmem_cache *nand_pages_slab;
311 
312 	/* Internal buffer of page + OOB size bytes */
313 	union ns_mem buf;
314 
315 	/* NAND flash "geometry" */
316 	struct {
317 		uint64_t totsz;     /* total flash size, bytes */
318 		uint32_t secsz;     /* flash sector (erase block) size, bytes */
319 		uint pgsz;          /* NAND flash page size, bytes */
320 		uint oobsz;         /* page OOB area size, bytes */
321 		uint64_t totszoob;  /* total flash size including OOB, bytes */
322 		uint pgszoob;       /* page size including OOB , bytes*/
323 		uint secszoob;      /* sector size including OOB, bytes */
324 		uint pgnum;         /* total number of pages */
325 		uint pgsec;         /* number of pages per sector */
326 		uint secshift;      /* bits number in sector size */
327 		uint pgshift;       /* bits number in page size */
328 		uint pgaddrbytes;   /* bytes per page address */
329 		uint secaddrbytes;  /* bytes per sector address */
330 		uint idbytes;       /* the number ID bytes that this chip outputs */
331 	} geom;
332 
333 	/* NAND flash internal registers */
334 	struct {
335 		unsigned command; /* the command register */
336 		u_char   status;  /* the status register */
337 		uint     row;     /* the page number */
338 		uint     column;  /* the offset within page */
339 		uint     count;   /* internal counter */
340 		uint     num;     /* number of bytes which must be processed */
341 		uint     off;     /* fixed page offset */
342 	} regs;
343 
344 	/* NAND flash lines state */
345         struct {
346                 int ce;  /* chip Enable */
347                 int cle; /* command Latch Enable */
348                 int ale; /* address Latch Enable */
349                 int wp;  /* write Protect */
350         } lines;
351 
352 	/* Fields needed when using a cache file */
353 	struct file *cfile; /* Open file */
354 	unsigned long *pages_written; /* Which pages have been written */
355 	void *file_buf;
356 	struct page *held_pages[NS_MAX_HELD_PAGES];
357 	int held_cnt;
358 
359 	/* debugfs entry */
360 	struct dentry *dent;
361 };
362 
363 /*
364  * Operations array. To perform any operation the simulator must pass
365  * through the correspondent states chain.
366  */
367 static struct nandsim_operations {
368 	uint32_t reqopts;  /* options which are required to perform the operation */
369 	uint32_t states[NS_OPER_STATES]; /* operation's states */
370 } ops[NS_OPER_NUM] = {
371 	/* Read page + OOB from the beginning */
372 	{OPT_SMALLPAGE, {STATE_CMD_READ0 | ACTION_ZEROOFF, STATE_ADDR_PAGE | ACTION_CPY,
373 			STATE_DATAOUT, STATE_READY}},
374 	/* Read page + OOB from the second half */
375 	{OPT_PAGE512_8BIT, {STATE_CMD_READ1 | ACTION_HALFOFF, STATE_ADDR_PAGE | ACTION_CPY,
376 			STATE_DATAOUT, STATE_READY}},
377 	/* Read OOB */
378 	{OPT_SMALLPAGE, {STATE_CMD_READOOB | ACTION_OOBOFF, STATE_ADDR_PAGE | ACTION_CPY,
379 			STATE_DATAOUT, STATE_READY}},
380 	/* Program page starting from the beginning */
381 	{OPT_ANY, {STATE_CMD_SEQIN, STATE_ADDR_PAGE, STATE_DATAIN,
382 			STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
383 	/* Program page starting from the beginning */
384 	{OPT_SMALLPAGE, {STATE_CMD_READ0, STATE_CMD_SEQIN | ACTION_ZEROOFF, STATE_ADDR_PAGE,
385 			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
386 	/* Program page starting from the second half */
387 	{OPT_PAGE512, {STATE_CMD_READ1, STATE_CMD_SEQIN | ACTION_HALFOFF, STATE_ADDR_PAGE,
388 			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
389 	/* Program OOB */
390 	{OPT_SMALLPAGE, {STATE_CMD_READOOB, STATE_CMD_SEQIN | ACTION_OOBOFF, STATE_ADDR_PAGE,
391 			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
392 	/* Erase sector */
393 	{OPT_ANY, {STATE_CMD_ERASE1, STATE_ADDR_SEC, STATE_CMD_ERASE2 | ACTION_SECERASE, STATE_READY}},
394 	/* Read status */
395 	{OPT_ANY, {STATE_CMD_STATUS, STATE_DATAOUT_STATUS, STATE_READY}},
396 	/* Read ID */
397 	{OPT_ANY, {STATE_CMD_READID, STATE_ADDR_ZERO, STATE_DATAOUT_ID, STATE_READY}},
398 	/* Large page devices read page */
399 	{OPT_LARGEPAGE, {STATE_CMD_READ0, STATE_ADDR_PAGE, STATE_CMD_READSTART | ACTION_CPY,
400 			       STATE_DATAOUT, STATE_READY}},
401 	/* Large page devices random page read */
402 	{OPT_LARGEPAGE, {STATE_CMD_RNDOUT, STATE_ADDR_COLUMN, STATE_CMD_RNDOUTSTART | ACTION_CPY,
403 			       STATE_DATAOUT, STATE_READY}},
404 };
405 
406 struct weak_block {
407 	struct list_head list;
408 	unsigned int erase_block_no;
409 	unsigned int max_erases;
410 	unsigned int erases_done;
411 };
412 
413 static LIST_HEAD(weak_blocks);
414 
415 struct weak_page {
416 	struct list_head list;
417 	unsigned int page_no;
418 	unsigned int max_writes;
419 	unsigned int writes_done;
420 };
421 
422 static LIST_HEAD(weak_pages);
423 
424 struct grave_page {
425 	struct list_head list;
426 	unsigned int page_no;
427 	unsigned int max_reads;
428 	unsigned int reads_done;
429 };
430 
431 static LIST_HEAD(grave_pages);
432 
433 static unsigned long *erase_block_wear = NULL;
434 static unsigned int wear_eb_count = 0;
435 static unsigned long total_wear = 0;
436 
437 /* MTD structure for NAND controller */
438 static struct mtd_info *nsmtd;
439 
440 static int ns_show(struct seq_file *m, void *private)
441 {
442 	unsigned long wmin = -1, wmax = 0, avg;
443 	unsigned long deciles[10], decile_max[10], tot = 0;
444 	unsigned int i;
445 
446 	/* Calc wear stats */
447 	for (i = 0; i < wear_eb_count; ++i) {
448 		unsigned long wear = erase_block_wear[i];
449 		if (wear < wmin)
450 			wmin = wear;
451 		if (wear > wmax)
452 			wmax = wear;
453 		tot += wear;
454 	}
455 
456 	for (i = 0; i < 9; ++i) {
457 		deciles[i] = 0;
458 		decile_max[i] = (wmax * (i + 1) + 5) / 10;
459 	}
460 	deciles[9] = 0;
461 	decile_max[9] = wmax;
462 	for (i = 0; i < wear_eb_count; ++i) {
463 		int d;
464 		unsigned long wear = erase_block_wear[i];
465 		for (d = 0; d < 10; ++d)
466 			if (wear <= decile_max[d]) {
467 				deciles[d] += 1;
468 				break;
469 			}
470 	}
471 	avg = tot / wear_eb_count;
472 
473 	/* Output wear report */
474 	seq_printf(m, "Total numbers of erases:  %lu\n", tot);
475 	seq_printf(m, "Number of erase blocks:   %u\n", wear_eb_count);
476 	seq_printf(m, "Average number of erases: %lu\n", avg);
477 	seq_printf(m, "Maximum number of erases: %lu\n", wmax);
478 	seq_printf(m, "Minimum number of erases: %lu\n", wmin);
479 	for (i = 0; i < 10; ++i) {
480 		unsigned long from = (i ? decile_max[i - 1] + 1 : 0);
481 		if (from > decile_max[i])
482 			continue;
483 		seq_printf(m, "Number of ebs with erase counts from %lu to %lu : %lu\n",
484 			from,
485 			decile_max[i],
486 			deciles[i]);
487 	}
488 
489 	return 0;
490 }
491 DEFINE_SHOW_ATTRIBUTE(ns);
492 
493 /**
494  * ns_debugfs_create - initialize debugfs
495  * @ns: nandsim device description object
496  *
497  * This function creates all debugfs files for UBI device @ubi. Returns zero in
498  * case of success and a negative error code in case of failure.
499  */
500 static int ns_debugfs_create(struct nandsim *ns)
501 {
502 	struct dentry *root = nsmtd->dbg.dfs_dir;
503 
504 	/*
505 	 * Just skip debugfs initialization when the debugfs directory is
506 	 * missing.
507 	 */
508 	if (IS_ERR_OR_NULL(root)) {
509 		if (IS_ENABLED(CONFIG_DEBUG_FS) &&
510 		    !IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER))
511 			NS_WARN("CONFIG_MTD_PARTITIONED_MASTER must be enabled to expose debugfs stuff\n");
512 		return 0;
513 	}
514 
515 	ns->dent = debugfs_create_file("nandsim_wear_report", 0400, root, ns,
516 				       &ns_fops);
517 	if (IS_ERR_OR_NULL(ns->dent)) {
518 		NS_ERR("cannot create \"nandsim_wear_report\" debugfs entry\n");
519 		return -1;
520 	}
521 
522 	return 0;
523 }
524 
525 static void ns_debugfs_remove(struct nandsim *ns)
526 {
527 	debugfs_remove_recursive(ns->dent);
528 }
529 
530 /*
531  * Allocate array of page pointers, create slab allocation for an array
532  * and initialize the array by NULL pointers.
533  *
534  * RETURNS: 0 if success, -ENOMEM if memory alloc fails.
535  */
536 static int __init ns_alloc_device(struct nandsim *ns)
537 {
538 	struct file *cfile;
539 	int i, err;
540 
541 	if (cache_file) {
542 		cfile = filp_open(cache_file, O_CREAT | O_RDWR | O_LARGEFILE, 0600);
543 		if (IS_ERR(cfile))
544 			return PTR_ERR(cfile);
545 		if (!(cfile->f_mode & FMODE_CAN_READ)) {
546 			NS_ERR("alloc_device: cache file not readable\n");
547 			err = -EINVAL;
548 			goto err_close_filp;
549 		}
550 		if (!(cfile->f_mode & FMODE_CAN_WRITE)) {
551 			NS_ERR("alloc_device: cache file not writeable\n");
552 			err = -EINVAL;
553 			goto err_close_filp;
554 		}
555 		ns->pages_written =
556 			vzalloc(array_size(sizeof(unsigned long),
557 					   BITS_TO_LONGS(ns->geom.pgnum)));
558 		if (!ns->pages_written) {
559 			NS_ERR("alloc_device: unable to allocate pages written array\n");
560 			err = -ENOMEM;
561 			goto err_close_filp;
562 		}
563 		ns->file_buf = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
564 		if (!ns->file_buf) {
565 			NS_ERR("alloc_device: unable to allocate file buf\n");
566 			err = -ENOMEM;
567 			goto err_free_pw;
568 		}
569 		ns->cfile = cfile;
570 
571 		return 0;
572 
573 err_free_pw:
574 		vfree(ns->pages_written);
575 err_close_filp:
576 		filp_close(cfile, NULL);
577 
578 		return err;
579 	}
580 
581 	ns->pages = vmalloc(array_size(sizeof(union ns_mem), ns->geom.pgnum));
582 	if (!ns->pages) {
583 		NS_ERR("alloc_device: unable to allocate page array\n");
584 		return -ENOMEM;
585 	}
586 	for (i = 0; i < ns->geom.pgnum; i++) {
587 		ns->pages[i].byte = NULL;
588 	}
589 	ns->nand_pages_slab = kmem_cache_create("nandsim",
590 						ns->geom.pgszoob, 0, 0, NULL);
591 	if (!ns->nand_pages_slab) {
592 		NS_ERR("cache_create: unable to create kmem_cache\n");
593 		err = -ENOMEM;
594 		goto err_free_pg;
595 	}
596 
597 	return 0;
598 
599 err_free_pg:
600 	vfree(ns->pages);
601 
602 	return err;
603 }
604 
605 /*
606  * Free any allocated pages, and free the array of page pointers.
607  */
608 static void ns_free_device(struct nandsim *ns)
609 {
610 	int i;
611 
612 	if (ns->cfile) {
613 		kfree(ns->file_buf);
614 		vfree(ns->pages_written);
615 		filp_close(ns->cfile, NULL);
616 		return;
617 	}
618 
619 	if (ns->pages) {
620 		for (i = 0; i < ns->geom.pgnum; i++) {
621 			if (ns->pages[i].byte)
622 				kmem_cache_free(ns->nand_pages_slab,
623 						ns->pages[i].byte);
624 		}
625 		kmem_cache_destroy(ns->nand_pages_slab);
626 		vfree(ns->pages);
627 	}
628 }
629 
630 static char __init *ns_get_partition_name(int i)
631 {
632 	return kasprintf(GFP_KERNEL, "NAND simulator partition %d", i);
633 }
634 
635 /*
636  * Initialize the nandsim structure.
637  *
638  * RETURNS: 0 if success, -ERRNO if failure.
639  */
640 static int __init ns_init(struct mtd_info *mtd)
641 {
642 	struct nand_chip *chip = mtd_to_nand(mtd);
643 	struct nandsim   *ns   = nand_get_controller_data(chip);
644 	int i, ret = 0;
645 	uint64_t remains;
646 	uint64_t next_offset;
647 
648 	if (NS_IS_INITIALIZED(ns)) {
649 		NS_ERR("init_nandsim: nandsim is already initialized\n");
650 		return -EIO;
651 	}
652 
653 	/* Initialize the NAND flash parameters */
654 	ns->busw = chip->options & NAND_BUSWIDTH_16 ? 16 : 8;
655 	ns->geom.totsz    = mtd->size;
656 	ns->geom.pgsz     = mtd->writesize;
657 	ns->geom.oobsz    = mtd->oobsize;
658 	ns->geom.secsz    = mtd->erasesize;
659 	ns->geom.pgszoob  = ns->geom.pgsz + ns->geom.oobsz;
660 	ns->geom.pgnum    = div_u64(ns->geom.totsz, ns->geom.pgsz);
661 	ns->geom.totszoob = ns->geom.totsz + (uint64_t)ns->geom.pgnum * ns->geom.oobsz;
662 	ns->geom.secshift = ffs(ns->geom.secsz) - 1;
663 	ns->geom.pgshift  = chip->page_shift;
664 	ns->geom.pgsec    = ns->geom.secsz / ns->geom.pgsz;
665 	ns->geom.secszoob = ns->geom.secsz + ns->geom.oobsz * ns->geom.pgsec;
666 	ns->options = 0;
667 
668 	if (ns->geom.pgsz == 512) {
669 		ns->options |= OPT_PAGE512;
670 		if (ns->busw == 8)
671 			ns->options |= OPT_PAGE512_8BIT;
672 	} else if (ns->geom.pgsz == 2048) {
673 		ns->options |= OPT_PAGE2048;
674 	} else if (ns->geom.pgsz == 4096) {
675 		ns->options |= OPT_PAGE4096;
676 	} else {
677 		NS_ERR("init_nandsim: unknown page size %u\n", ns->geom.pgsz);
678 		return -EIO;
679 	}
680 
681 	if (ns->options & OPT_SMALLPAGE) {
682 		if (ns->geom.totsz <= (32 << 20)) {
683 			ns->geom.pgaddrbytes  = 3;
684 			ns->geom.secaddrbytes = 2;
685 		} else {
686 			ns->geom.pgaddrbytes  = 4;
687 			ns->geom.secaddrbytes = 3;
688 		}
689 	} else {
690 		if (ns->geom.totsz <= (128 << 20)) {
691 			ns->geom.pgaddrbytes  = 4;
692 			ns->geom.secaddrbytes = 2;
693 		} else {
694 			ns->geom.pgaddrbytes  = 5;
695 			ns->geom.secaddrbytes = 3;
696 		}
697 	}
698 
699 	/* Fill the partition_info structure */
700 	if (parts_num > ARRAY_SIZE(ns->partitions)) {
701 		NS_ERR("too many partitions.\n");
702 		return -EINVAL;
703 	}
704 	remains = ns->geom.totsz;
705 	next_offset = 0;
706 	for (i = 0; i < parts_num; ++i) {
707 		uint64_t part_sz = (uint64_t)parts[i] * ns->geom.secsz;
708 
709 		if (!part_sz || part_sz > remains) {
710 			NS_ERR("bad partition size.\n");
711 			return -EINVAL;
712 		}
713 		ns->partitions[i].name = ns_get_partition_name(i);
714 		if (!ns->partitions[i].name) {
715 			NS_ERR("unable to allocate memory.\n");
716 			return -ENOMEM;
717 		}
718 		ns->partitions[i].offset = next_offset;
719 		ns->partitions[i].size   = part_sz;
720 		next_offset += ns->partitions[i].size;
721 		remains -= ns->partitions[i].size;
722 	}
723 	ns->nbparts = parts_num;
724 	if (remains) {
725 		if (parts_num + 1 > ARRAY_SIZE(ns->partitions)) {
726 			NS_ERR("too many partitions.\n");
727 			ret = -EINVAL;
728 			goto free_partition_names;
729 		}
730 		ns->partitions[i].name = ns_get_partition_name(i);
731 		if (!ns->partitions[i].name) {
732 			NS_ERR("unable to allocate memory.\n");
733 			ret = -ENOMEM;
734 			goto free_partition_names;
735 		}
736 		ns->partitions[i].offset = next_offset;
737 		ns->partitions[i].size   = remains;
738 		ns->nbparts += 1;
739 	}
740 
741 	if (ns->busw == 16)
742 		NS_WARN("16-bit flashes support wasn't tested\n");
743 
744 	printk("flash size: %llu MiB\n",
745 			(unsigned long long)ns->geom.totsz >> 20);
746 	printk("page size: %u bytes\n",         ns->geom.pgsz);
747 	printk("OOB area size: %u bytes\n",     ns->geom.oobsz);
748 	printk("sector size: %u KiB\n",         ns->geom.secsz >> 10);
749 	printk("pages number: %u\n",            ns->geom.pgnum);
750 	printk("pages per sector: %u\n",        ns->geom.pgsec);
751 	printk("bus width: %u\n",               ns->busw);
752 	printk("bits in sector size: %u\n",     ns->geom.secshift);
753 	printk("bits in page size: %u\n",       ns->geom.pgshift);
754 	printk("bits in OOB size: %u\n",	ffs(ns->geom.oobsz) - 1);
755 	printk("flash size with OOB: %llu KiB\n",
756 			(unsigned long long)ns->geom.totszoob >> 10);
757 	printk("page address bytes: %u\n",      ns->geom.pgaddrbytes);
758 	printk("sector address bytes: %u\n",    ns->geom.secaddrbytes);
759 	printk("options: %#x\n",                ns->options);
760 
761 	ret = ns_alloc_device(ns);
762 	if (ret)
763 		goto free_partition_names;
764 
765 	/* Allocate / initialize the internal buffer */
766 	ns->buf.byte = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
767 	if (!ns->buf.byte) {
768 		NS_ERR("init_nandsim: unable to allocate %u bytes for the internal buffer\n",
769 			ns->geom.pgszoob);
770 		ret = -ENOMEM;
771 		goto free_device;
772 	}
773 	memset(ns->buf.byte, 0xFF, ns->geom.pgszoob);
774 
775 	return 0;
776 
777 free_device:
778 	ns_free_device(ns);
779 free_partition_names:
780 	for (i = 0; i < ARRAY_SIZE(ns->partitions); ++i)
781 		kfree(ns->partitions[i].name);
782 
783 	return ret;
784 }
785 
786 /*
787  * Free the nandsim structure.
788  */
789 static void ns_free(struct nandsim *ns)
790 {
791 	int i;
792 
793 	for (i = 0; i < ARRAY_SIZE(ns->partitions); ++i)
794 		kfree(ns->partitions[i].name);
795 
796 	kfree(ns->buf.byte);
797 	ns_free_device(ns);
798 
799 	return;
800 }
801 
802 static int ns_parse_badblocks(struct nandsim *ns, struct mtd_info *mtd)
803 {
804 	char *w;
805 	int zero_ok;
806 	unsigned int erase_block_no;
807 	loff_t offset;
808 
809 	if (!badblocks)
810 		return 0;
811 	w = badblocks;
812 	do {
813 		zero_ok = (*w == '0' ? 1 : 0);
814 		erase_block_no = simple_strtoul(w, &w, 0);
815 		if (!zero_ok && !erase_block_no) {
816 			NS_ERR("invalid badblocks.\n");
817 			return -EINVAL;
818 		}
819 		offset = (loff_t)erase_block_no * ns->geom.secsz;
820 		if (mtd_block_markbad(mtd, offset)) {
821 			NS_ERR("invalid badblocks.\n");
822 			return -EINVAL;
823 		}
824 		if (*w == ',')
825 			w += 1;
826 	} while (*w);
827 	return 0;
828 }
829 
830 static int ns_parse_weakblocks(void)
831 {
832 	char *w;
833 	int zero_ok;
834 	unsigned int erase_block_no;
835 	unsigned int max_erases;
836 	struct weak_block *wb;
837 
838 	if (!weakblocks)
839 		return 0;
840 	w = weakblocks;
841 	do {
842 		zero_ok = (*w == '0' ? 1 : 0);
843 		erase_block_no = simple_strtoul(w, &w, 0);
844 		if (!zero_ok && !erase_block_no) {
845 			NS_ERR("invalid weakblocks.\n");
846 			return -EINVAL;
847 		}
848 		max_erases = 3;
849 		if (*w == ':') {
850 			w += 1;
851 			max_erases = simple_strtoul(w, &w, 0);
852 		}
853 		if (*w == ',')
854 			w += 1;
855 		wb = kzalloc(sizeof(*wb), GFP_KERNEL);
856 		if (!wb) {
857 			NS_ERR("unable to allocate memory.\n");
858 			return -ENOMEM;
859 		}
860 		wb->erase_block_no = erase_block_no;
861 		wb->max_erases = max_erases;
862 		list_add(&wb->list, &weak_blocks);
863 	} while (*w);
864 	return 0;
865 }
866 
867 static int ns_erase_error(unsigned int erase_block_no)
868 {
869 	struct weak_block *wb;
870 
871 	list_for_each_entry(wb, &weak_blocks, list)
872 		if (wb->erase_block_no == erase_block_no) {
873 			if (wb->erases_done >= wb->max_erases)
874 				return 1;
875 			wb->erases_done += 1;
876 			return 0;
877 		}
878 	return 0;
879 }
880 
881 static int ns_parse_weakpages(void)
882 {
883 	char *w;
884 	int zero_ok;
885 	unsigned int page_no;
886 	unsigned int max_writes;
887 	struct weak_page *wp;
888 
889 	if (!weakpages)
890 		return 0;
891 	w = weakpages;
892 	do {
893 		zero_ok = (*w == '0' ? 1 : 0);
894 		page_no = simple_strtoul(w, &w, 0);
895 		if (!zero_ok && !page_no) {
896 			NS_ERR("invalid weakpages.\n");
897 			return -EINVAL;
898 		}
899 		max_writes = 3;
900 		if (*w == ':') {
901 			w += 1;
902 			max_writes = simple_strtoul(w, &w, 0);
903 		}
904 		if (*w == ',')
905 			w += 1;
906 		wp = kzalloc(sizeof(*wp), GFP_KERNEL);
907 		if (!wp) {
908 			NS_ERR("unable to allocate memory.\n");
909 			return -ENOMEM;
910 		}
911 		wp->page_no = page_no;
912 		wp->max_writes = max_writes;
913 		list_add(&wp->list, &weak_pages);
914 	} while (*w);
915 	return 0;
916 }
917 
918 static int ns_write_error(unsigned int page_no)
919 {
920 	struct weak_page *wp;
921 
922 	list_for_each_entry(wp, &weak_pages, list)
923 		if (wp->page_no == page_no) {
924 			if (wp->writes_done >= wp->max_writes)
925 				return 1;
926 			wp->writes_done += 1;
927 			return 0;
928 		}
929 	return 0;
930 }
931 
932 static int ns_parse_gravepages(void)
933 {
934 	char *g;
935 	int zero_ok;
936 	unsigned int page_no;
937 	unsigned int max_reads;
938 	struct grave_page *gp;
939 
940 	if (!gravepages)
941 		return 0;
942 	g = gravepages;
943 	do {
944 		zero_ok = (*g == '0' ? 1 : 0);
945 		page_no = simple_strtoul(g, &g, 0);
946 		if (!zero_ok && !page_no) {
947 			NS_ERR("invalid gravepagess.\n");
948 			return -EINVAL;
949 		}
950 		max_reads = 3;
951 		if (*g == ':') {
952 			g += 1;
953 			max_reads = simple_strtoul(g, &g, 0);
954 		}
955 		if (*g == ',')
956 			g += 1;
957 		gp = kzalloc(sizeof(*gp), GFP_KERNEL);
958 		if (!gp) {
959 			NS_ERR("unable to allocate memory.\n");
960 			return -ENOMEM;
961 		}
962 		gp->page_no = page_no;
963 		gp->max_reads = max_reads;
964 		list_add(&gp->list, &grave_pages);
965 	} while (*g);
966 	return 0;
967 }
968 
969 static int ns_read_error(unsigned int page_no)
970 {
971 	struct grave_page *gp;
972 
973 	list_for_each_entry(gp, &grave_pages, list)
974 		if (gp->page_no == page_no) {
975 			if (gp->reads_done >= gp->max_reads)
976 				return 1;
977 			gp->reads_done += 1;
978 			return 0;
979 		}
980 	return 0;
981 }
982 
983 static int ns_setup_wear_reporting(struct mtd_info *mtd)
984 {
985 	wear_eb_count = div_u64(mtd->size, mtd->erasesize);
986 	erase_block_wear = kcalloc(wear_eb_count, sizeof(unsigned long), GFP_KERNEL);
987 	if (!erase_block_wear) {
988 		NS_ERR("Too many erase blocks for wear reporting\n");
989 		return -ENOMEM;
990 	}
991 	return 0;
992 }
993 
994 static void ns_update_wear(unsigned int erase_block_no)
995 {
996 	if (!erase_block_wear)
997 		return;
998 	total_wear += 1;
999 	/*
1000 	 * TODO: Notify this through a debugfs entry,
1001 	 * instead of showing an error message.
1002 	 */
1003 	if (total_wear == 0)
1004 		NS_ERR("Erase counter total overflow\n");
1005 	erase_block_wear[erase_block_no] += 1;
1006 	if (erase_block_wear[erase_block_no] == 0)
1007 		NS_ERR("Erase counter overflow for erase block %u\n", erase_block_no);
1008 }
1009 
1010 /*
1011  * Returns the string representation of 'state' state.
1012  */
1013 static char *ns_get_state_name(uint32_t state)
1014 {
1015 	switch (NS_STATE(state)) {
1016 		case STATE_CMD_READ0:
1017 			return "STATE_CMD_READ0";
1018 		case STATE_CMD_READ1:
1019 			return "STATE_CMD_READ1";
1020 		case STATE_CMD_PAGEPROG:
1021 			return "STATE_CMD_PAGEPROG";
1022 		case STATE_CMD_READOOB:
1023 			return "STATE_CMD_READOOB";
1024 		case STATE_CMD_READSTART:
1025 			return "STATE_CMD_READSTART";
1026 		case STATE_CMD_ERASE1:
1027 			return "STATE_CMD_ERASE1";
1028 		case STATE_CMD_STATUS:
1029 			return "STATE_CMD_STATUS";
1030 		case STATE_CMD_SEQIN:
1031 			return "STATE_CMD_SEQIN";
1032 		case STATE_CMD_READID:
1033 			return "STATE_CMD_READID";
1034 		case STATE_CMD_ERASE2:
1035 			return "STATE_CMD_ERASE2";
1036 		case STATE_CMD_RESET:
1037 			return "STATE_CMD_RESET";
1038 		case STATE_CMD_RNDOUT:
1039 			return "STATE_CMD_RNDOUT";
1040 		case STATE_CMD_RNDOUTSTART:
1041 			return "STATE_CMD_RNDOUTSTART";
1042 		case STATE_ADDR_PAGE:
1043 			return "STATE_ADDR_PAGE";
1044 		case STATE_ADDR_SEC:
1045 			return "STATE_ADDR_SEC";
1046 		case STATE_ADDR_ZERO:
1047 			return "STATE_ADDR_ZERO";
1048 		case STATE_ADDR_COLUMN:
1049 			return "STATE_ADDR_COLUMN";
1050 		case STATE_DATAIN:
1051 			return "STATE_DATAIN";
1052 		case STATE_DATAOUT:
1053 			return "STATE_DATAOUT";
1054 		case STATE_DATAOUT_ID:
1055 			return "STATE_DATAOUT_ID";
1056 		case STATE_DATAOUT_STATUS:
1057 			return "STATE_DATAOUT_STATUS";
1058 		case STATE_READY:
1059 			return "STATE_READY";
1060 		case STATE_UNKNOWN:
1061 			return "STATE_UNKNOWN";
1062 	}
1063 
1064 	NS_ERR("get_state_name: unknown state, BUG\n");
1065 	return NULL;
1066 }
1067 
1068 /*
1069  * Check if command is valid.
1070  *
1071  * RETURNS: 1 if wrong command, 0 if right.
1072  */
1073 static int ns_check_command(int cmd)
1074 {
1075 	switch (cmd) {
1076 
1077 	case NAND_CMD_READ0:
1078 	case NAND_CMD_READ1:
1079 	case NAND_CMD_READSTART:
1080 	case NAND_CMD_PAGEPROG:
1081 	case NAND_CMD_READOOB:
1082 	case NAND_CMD_ERASE1:
1083 	case NAND_CMD_STATUS:
1084 	case NAND_CMD_SEQIN:
1085 	case NAND_CMD_READID:
1086 	case NAND_CMD_ERASE2:
1087 	case NAND_CMD_RESET:
1088 	case NAND_CMD_RNDOUT:
1089 	case NAND_CMD_RNDOUTSTART:
1090 		return 0;
1091 
1092 	default:
1093 		return 1;
1094 	}
1095 }
1096 
1097 /*
1098  * Returns state after command is accepted by command number.
1099  */
1100 static uint32_t ns_get_state_by_command(unsigned command)
1101 {
1102 	switch (command) {
1103 		case NAND_CMD_READ0:
1104 			return STATE_CMD_READ0;
1105 		case NAND_CMD_READ1:
1106 			return STATE_CMD_READ1;
1107 		case NAND_CMD_PAGEPROG:
1108 			return STATE_CMD_PAGEPROG;
1109 		case NAND_CMD_READSTART:
1110 			return STATE_CMD_READSTART;
1111 		case NAND_CMD_READOOB:
1112 			return STATE_CMD_READOOB;
1113 		case NAND_CMD_ERASE1:
1114 			return STATE_CMD_ERASE1;
1115 		case NAND_CMD_STATUS:
1116 			return STATE_CMD_STATUS;
1117 		case NAND_CMD_SEQIN:
1118 			return STATE_CMD_SEQIN;
1119 		case NAND_CMD_READID:
1120 			return STATE_CMD_READID;
1121 		case NAND_CMD_ERASE2:
1122 			return STATE_CMD_ERASE2;
1123 		case NAND_CMD_RESET:
1124 			return STATE_CMD_RESET;
1125 		case NAND_CMD_RNDOUT:
1126 			return STATE_CMD_RNDOUT;
1127 		case NAND_CMD_RNDOUTSTART:
1128 			return STATE_CMD_RNDOUTSTART;
1129 	}
1130 
1131 	NS_ERR("get_state_by_command: unknown command, BUG\n");
1132 	return 0;
1133 }
1134 
1135 /*
1136  * Move an address byte to the correspondent internal register.
1137  */
1138 static inline void ns_accept_addr_byte(struct nandsim *ns, u_char bt)
1139 {
1140 	uint byte = (uint)bt;
1141 
1142 	if (ns->regs.count < (ns->geom.pgaddrbytes - ns->geom.secaddrbytes))
1143 		ns->regs.column |= (byte << 8 * ns->regs.count);
1144 	else {
1145 		ns->regs.row |= (byte << 8 * (ns->regs.count -
1146 						ns->geom.pgaddrbytes +
1147 						ns->geom.secaddrbytes));
1148 	}
1149 
1150 	return;
1151 }
1152 
1153 /*
1154  * Switch to STATE_READY state.
1155  */
1156 static inline void ns_switch_to_ready_state(struct nandsim *ns, u_char status)
1157 {
1158 	NS_DBG("switch_to_ready_state: switch to %s state\n",
1159 	       ns_get_state_name(STATE_READY));
1160 
1161 	ns->state       = STATE_READY;
1162 	ns->nxstate     = STATE_UNKNOWN;
1163 	ns->op          = NULL;
1164 	ns->npstates    = 0;
1165 	ns->stateidx    = 0;
1166 	ns->regs.num    = 0;
1167 	ns->regs.count  = 0;
1168 	ns->regs.off    = 0;
1169 	ns->regs.row    = 0;
1170 	ns->regs.column = 0;
1171 	ns->regs.status = status;
1172 }
1173 
1174 /*
1175  * If the operation isn't known yet, try to find it in the global array
1176  * of supported operations.
1177  *
1178  * Operation can be unknown because of the following.
1179  *   1. New command was accepted and this is the first call to find the
1180  *      correspondent states chain. In this case ns->npstates = 0;
1181  *   2. There are several operations which begin with the same command(s)
1182  *      (for example program from the second half and read from the
1183  *      second half operations both begin with the READ1 command). In this
1184  *      case the ns->pstates[] array contains previous states.
1185  *
1186  * Thus, the function tries to find operation containing the following
1187  * states (if the 'flag' parameter is 0):
1188  *    ns->pstates[0], ... ns->pstates[ns->npstates], ns->state
1189  *
1190  * If (one and only one) matching operation is found, it is accepted (
1191  * ns->ops, ns->state, ns->nxstate are initialized, ns->npstate is
1192  * zeroed).
1193  *
1194  * If there are several matches, the current state is pushed to the
1195  * ns->pstates.
1196  *
1197  * The operation can be unknown only while commands are input to the chip.
1198  * As soon as address command is accepted, the operation must be known.
1199  * In such situation the function is called with 'flag' != 0, and the
1200  * operation is searched using the following pattern:
1201  *     ns->pstates[0], ... ns->pstates[ns->npstates], <address input>
1202  *
1203  * It is supposed that this pattern must either match one operation or
1204  * none. There can't be ambiguity in that case.
1205  *
1206  * If no matches found, the function does the following:
1207  *   1. if there are saved states present, try to ignore them and search
1208  *      again only using the last command. If nothing was found, switch
1209  *      to the STATE_READY state.
1210  *   2. if there are no saved states, switch to the STATE_READY state.
1211  *
1212  * RETURNS: -2 - no matched operations found.
1213  *          -1 - several matches.
1214  *           0 - operation is found.
1215  */
1216 static int ns_find_operation(struct nandsim *ns, uint32_t flag)
1217 {
1218 	int opsfound = 0;
1219 	int i, j, idx = 0;
1220 
1221 	for (i = 0; i < NS_OPER_NUM; i++) {
1222 
1223 		int found = 1;
1224 
1225 		if (!(ns->options & ops[i].reqopts))
1226 			/* Ignore operations we can't perform */
1227 			continue;
1228 
1229 		if (flag) {
1230 			if (!(ops[i].states[ns->npstates] & STATE_ADDR_MASK))
1231 				continue;
1232 		} else {
1233 			if (NS_STATE(ns->state) != NS_STATE(ops[i].states[ns->npstates]))
1234 				continue;
1235 		}
1236 
1237 		for (j = 0; j < ns->npstates; j++)
1238 			if (NS_STATE(ops[i].states[j]) != NS_STATE(ns->pstates[j])
1239 				&& (ns->options & ops[idx].reqopts)) {
1240 				found = 0;
1241 				break;
1242 			}
1243 
1244 		if (found) {
1245 			idx = i;
1246 			opsfound += 1;
1247 		}
1248 	}
1249 
1250 	if (opsfound == 1) {
1251 		/* Exact match */
1252 		ns->op = &ops[idx].states[0];
1253 		if (flag) {
1254 			/*
1255 			 * In this case the find_operation function was
1256 			 * called when address has just began input. But it isn't
1257 			 * yet fully input and the current state must
1258 			 * not be one of STATE_ADDR_*, but the STATE_ADDR_*
1259 			 * state must be the next state (ns->nxstate).
1260 			 */
1261 			ns->stateidx = ns->npstates - 1;
1262 		} else {
1263 			ns->stateidx = ns->npstates;
1264 		}
1265 		ns->npstates = 0;
1266 		ns->state = ns->op[ns->stateidx];
1267 		ns->nxstate = ns->op[ns->stateidx + 1];
1268 		NS_DBG("find_operation: operation found, index: %d, state: %s, nxstate %s\n",
1269 		       idx, ns_get_state_name(ns->state),
1270 		       ns_get_state_name(ns->nxstate));
1271 		return 0;
1272 	}
1273 
1274 	if (opsfound == 0) {
1275 		/* Nothing was found. Try to ignore previous commands (if any) and search again */
1276 		if (ns->npstates != 0) {
1277 			NS_DBG("find_operation: no operation found, try again with state %s\n",
1278 			       ns_get_state_name(ns->state));
1279 			ns->npstates = 0;
1280 			return ns_find_operation(ns, 0);
1281 
1282 		}
1283 		NS_DBG("find_operation: no operations found\n");
1284 		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1285 		return -2;
1286 	}
1287 
1288 	if (flag) {
1289 		/* This shouldn't happen */
1290 		NS_DBG("find_operation: BUG, operation must be known if address is input\n");
1291 		return -2;
1292 	}
1293 
1294 	NS_DBG("find_operation: there is still ambiguity\n");
1295 
1296 	ns->pstates[ns->npstates++] = ns->state;
1297 
1298 	return -1;
1299 }
1300 
1301 static void ns_put_pages(struct nandsim *ns)
1302 {
1303 	int i;
1304 
1305 	for (i = 0; i < ns->held_cnt; i++)
1306 		put_page(ns->held_pages[i]);
1307 }
1308 
1309 /* Get page cache pages in advance to provide NOFS memory allocation */
1310 static int ns_get_pages(struct nandsim *ns, struct file *file, size_t count,
1311 			loff_t pos)
1312 {
1313 	pgoff_t index, start_index, end_index;
1314 	struct page *page;
1315 	struct address_space *mapping = file->f_mapping;
1316 
1317 	start_index = pos >> PAGE_SHIFT;
1318 	end_index = (pos + count - 1) >> PAGE_SHIFT;
1319 	if (end_index - start_index + 1 > NS_MAX_HELD_PAGES)
1320 		return -EINVAL;
1321 	ns->held_cnt = 0;
1322 	for (index = start_index; index <= end_index; index++) {
1323 		page = find_get_page(mapping, index);
1324 		if (page == NULL) {
1325 			page = find_or_create_page(mapping, index, GFP_NOFS);
1326 			if (page == NULL) {
1327 				write_inode_now(mapping->host, 1);
1328 				page = find_or_create_page(mapping, index, GFP_NOFS);
1329 			}
1330 			if (page == NULL) {
1331 				ns_put_pages(ns);
1332 				return -ENOMEM;
1333 			}
1334 			unlock_page(page);
1335 		}
1336 		ns->held_pages[ns->held_cnt++] = page;
1337 	}
1338 	return 0;
1339 }
1340 
1341 static ssize_t ns_read_file(struct nandsim *ns, struct file *file, void *buf,
1342 			    size_t count, loff_t pos)
1343 {
1344 	ssize_t tx;
1345 	int err;
1346 	unsigned int noreclaim_flag;
1347 
1348 	err = ns_get_pages(ns, file, count, pos);
1349 	if (err)
1350 		return err;
1351 	noreclaim_flag = memalloc_noreclaim_save();
1352 	tx = kernel_read(file, buf, count, &pos);
1353 	memalloc_noreclaim_restore(noreclaim_flag);
1354 	ns_put_pages(ns);
1355 	return tx;
1356 }
1357 
1358 static ssize_t ns_write_file(struct nandsim *ns, struct file *file, void *buf,
1359 			     size_t count, loff_t pos)
1360 {
1361 	ssize_t tx;
1362 	int err;
1363 	unsigned int noreclaim_flag;
1364 
1365 	err = ns_get_pages(ns, file, count, pos);
1366 	if (err)
1367 		return err;
1368 	noreclaim_flag = memalloc_noreclaim_save();
1369 	tx = kernel_write(file, buf, count, &pos);
1370 	memalloc_noreclaim_restore(noreclaim_flag);
1371 	ns_put_pages(ns);
1372 	return tx;
1373 }
1374 
1375 /*
1376  * Returns a pointer to the current page.
1377  */
1378 static inline union ns_mem *NS_GET_PAGE(struct nandsim *ns)
1379 {
1380 	return &(ns->pages[ns->regs.row]);
1381 }
1382 
1383 /*
1384  * Retuns a pointer to the current byte, within the current page.
1385  */
1386 static inline u_char *NS_PAGE_BYTE_OFF(struct nandsim *ns)
1387 {
1388 	return NS_GET_PAGE(ns)->byte + NS_PAGE_BYTE_SHIFT(ns);
1389 }
1390 
1391 static int ns_do_read_error(struct nandsim *ns, int num)
1392 {
1393 	unsigned int page_no = ns->regs.row;
1394 
1395 	if (ns_read_error(page_no)) {
1396 		prandom_bytes(ns->buf.byte, num);
1397 		NS_WARN("simulating read error in page %u\n", page_no);
1398 		return 1;
1399 	}
1400 	return 0;
1401 }
1402 
1403 static void ns_do_bit_flips(struct nandsim *ns, int num)
1404 {
1405 	if (bitflips && prandom_u32() < (1 << 22)) {
1406 		int flips = 1;
1407 		if (bitflips > 1)
1408 			flips = (prandom_u32() % (int) bitflips) + 1;
1409 		while (flips--) {
1410 			int pos = prandom_u32() % (num * 8);
1411 			ns->buf.byte[pos / 8] ^= (1 << (pos % 8));
1412 			NS_WARN("read_page: flipping bit %d in page %d "
1413 				"reading from %d ecc: corrected=%u failed=%u\n",
1414 				pos, ns->regs.row, NS_PAGE_BYTE_SHIFT(ns),
1415 				nsmtd->ecc_stats.corrected, nsmtd->ecc_stats.failed);
1416 		}
1417 	}
1418 }
1419 
1420 /*
1421  * Fill the NAND buffer with data read from the specified page.
1422  */
1423 static void ns_read_page(struct nandsim *ns, int num)
1424 {
1425 	union ns_mem *mypage;
1426 
1427 	if (ns->cfile) {
1428 		if (!test_bit(ns->regs.row, ns->pages_written)) {
1429 			NS_DBG("read_page: page %d not written\n", ns->regs.row);
1430 			memset(ns->buf.byte, 0xFF, num);
1431 		} else {
1432 			loff_t pos;
1433 			ssize_t tx;
1434 
1435 			NS_DBG("read_page: page %d written, reading from %d\n",
1436 				ns->regs.row, NS_PAGE_BYTE_SHIFT(ns));
1437 			if (ns_do_read_error(ns, num))
1438 				return;
1439 			pos = (loff_t)NS_RAW_OFFSET(ns) + ns->regs.off;
1440 			tx = ns_read_file(ns, ns->cfile, ns->buf.byte, num,
1441 					  pos);
1442 			if (tx != num) {
1443 				NS_ERR("read_page: read error for page %d ret %ld\n", ns->regs.row, (long)tx);
1444 				return;
1445 			}
1446 			ns_do_bit_flips(ns, num);
1447 		}
1448 		return;
1449 	}
1450 
1451 	mypage = NS_GET_PAGE(ns);
1452 	if (mypage->byte == NULL) {
1453 		NS_DBG("read_page: page %d not allocated\n", ns->regs.row);
1454 		memset(ns->buf.byte, 0xFF, num);
1455 	} else {
1456 		NS_DBG("read_page: page %d allocated, reading from %d\n",
1457 			ns->regs.row, NS_PAGE_BYTE_SHIFT(ns));
1458 		if (ns_do_read_error(ns, num))
1459 			return;
1460 		memcpy(ns->buf.byte, NS_PAGE_BYTE_OFF(ns), num);
1461 		ns_do_bit_flips(ns, num);
1462 	}
1463 }
1464 
1465 /*
1466  * Erase all pages in the specified sector.
1467  */
1468 static void ns_erase_sector(struct nandsim *ns)
1469 {
1470 	union ns_mem *mypage;
1471 	int i;
1472 
1473 	if (ns->cfile) {
1474 		for (i = 0; i < ns->geom.pgsec; i++)
1475 			if (__test_and_clear_bit(ns->regs.row + i,
1476 						 ns->pages_written)) {
1477 				NS_DBG("erase_sector: freeing page %d\n", ns->regs.row + i);
1478 			}
1479 		return;
1480 	}
1481 
1482 	mypage = NS_GET_PAGE(ns);
1483 	for (i = 0; i < ns->geom.pgsec; i++) {
1484 		if (mypage->byte != NULL) {
1485 			NS_DBG("erase_sector: freeing page %d\n", ns->regs.row+i);
1486 			kmem_cache_free(ns->nand_pages_slab, mypage->byte);
1487 			mypage->byte = NULL;
1488 		}
1489 		mypage++;
1490 	}
1491 }
1492 
1493 /*
1494  * Program the specified page with the contents from the NAND buffer.
1495  */
1496 static int ns_prog_page(struct nandsim *ns, int num)
1497 {
1498 	int i;
1499 	union ns_mem *mypage;
1500 	u_char *pg_off;
1501 
1502 	if (ns->cfile) {
1503 		loff_t off;
1504 		ssize_t tx;
1505 		int all;
1506 
1507 		NS_DBG("prog_page: writing page %d\n", ns->regs.row);
1508 		pg_off = ns->file_buf + NS_PAGE_BYTE_SHIFT(ns);
1509 		off = (loff_t)NS_RAW_OFFSET(ns) + ns->regs.off;
1510 		if (!test_bit(ns->regs.row, ns->pages_written)) {
1511 			all = 1;
1512 			memset(ns->file_buf, 0xff, ns->geom.pgszoob);
1513 		} else {
1514 			all = 0;
1515 			tx = ns_read_file(ns, ns->cfile, pg_off, num, off);
1516 			if (tx != num) {
1517 				NS_ERR("prog_page: read error for page %d ret %ld\n", ns->regs.row, (long)tx);
1518 				return -1;
1519 			}
1520 		}
1521 		for (i = 0; i < num; i++)
1522 			pg_off[i] &= ns->buf.byte[i];
1523 		if (all) {
1524 			loff_t pos = (loff_t)ns->regs.row * ns->geom.pgszoob;
1525 			tx = ns_write_file(ns, ns->cfile, ns->file_buf,
1526 					   ns->geom.pgszoob, pos);
1527 			if (tx != ns->geom.pgszoob) {
1528 				NS_ERR("prog_page: write error for page %d ret %ld\n", ns->regs.row, (long)tx);
1529 				return -1;
1530 			}
1531 			__set_bit(ns->regs.row, ns->pages_written);
1532 		} else {
1533 			tx = ns_write_file(ns, ns->cfile, pg_off, num, off);
1534 			if (tx != num) {
1535 				NS_ERR("prog_page: write error for page %d ret %ld\n", ns->regs.row, (long)tx);
1536 				return -1;
1537 			}
1538 		}
1539 		return 0;
1540 	}
1541 
1542 	mypage = NS_GET_PAGE(ns);
1543 	if (mypage->byte == NULL) {
1544 		NS_DBG("prog_page: allocating page %d\n", ns->regs.row);
1545 		/*
1546 		 * We allocate memory with GFP_NOFS because a flash FS may
1547 		 * utilize this. If it is holding an FS lock, then gets here,
1548 		 * then kernel memory alloc runs writeback which goes to the FS
1549 		 * again and deadlocks. This was seen in practice.
1550 		 */
1551 		mypage->byte = kmem_cache_alloc(ns->nand_pages_slab, GFP_NOFS);
1552 		if (mypage->byte == NULL) {
1553 			NS_ERR("prog_page: error allocating memory for page %d\n", ns->regs.row);
1554 			return -1;
1555 		}
1556 		memset(mypage->byte, 0xFF, ns->geom.pgszoob);
1557 	}
1558 
1559 	pg_off = NS_PAGE_BYTE_OFF(ns);
1560 	for (i = 0; i < num; i++)
1561 		pg_off[i] &= ns->buf.byte[i];
1562 
1563 	return 0;
1564 }
1565 
1566 /*
1567  * If state has any action bit, perform this action.
1568  *
1569  * RETURNS: 0 if success, -1 if error.
1570  */
1571 static int ns_do_state_action(struct nandsim *ns, uint32_t action)
1572 {
1573 	int num;
1574 	int busdiv = ns->busw == 8 ? 1 : 2;
1575 	unsigned int erase_block_no, page_no;
1576 
1577 	action &= ACTION_MASK;
1578 
1579 	/* Check that page address input is correct */
1580 	if (action != ACTION_SECERASE && ns->regs.row >= ns->geom.pgnum) {
1581 		NS_WARN("do_state_action: wrong page number (%#x)\n", ns->regs.row);
1582 		return -1;
1583 	}
1584 
1585 	switch (action) {
1586 
1587 	case ACTION_CPY:
1588 		/*
1589 		 * Copy page data to the internal buffer.
1590 		 */
1591 
1592 		/* Column shouldn't be very large */
1593 		if (ns->regs.column >= (ns->geom.pgszoob - ns->regs.off)) {
1594 			NS_ERR("do_state_action: column number is too large\n");
1595 			break;
1596 		}
1597 		num = ns->geom.pgszoob - NS_PAGE_BYTE_SHIFT(ns);
1598 		ns_read_page(ns, num);
1599 
1600 		NS_DBG("do_state_action: (ACTION_CPY:) copy %d bytes to int buf, raw offset %d\n",
1601 			num, NS_RAW_OFFSET(ns) + ns->regs.off);
1602 
1603 		if (ns->regs.off == 0)
1604 			NS_LOG("read page %d\n", ns->regs.row);
1605 		else if (ns->regs.off < ns->geom.pgsz)
1606 			NS_LOG("read page %d (second half)\n", ns->regs.row);
1607 		else
1608 			NS_LOG("read OOB of page %d\n", ns->regs.row);
1609 
1610 		NS_UDELAY(access_delay);
1611 		NS_UDELAY(input_cycle * ns->geom.pgsz / 1000 / busdiv);
1612 
1613 		break;
1614 
1615 	case ACTION_SECERASE:
1616 		/*
1617 		 * Erase sector.
1618 		 */
1619 
1620 		if (ns->lines.wp) {
1621 			NS_ERR("do_state_action: device is write-protected, ignore sector erase\n");
1622 			return -1;
1623 		}
1624 
1625 		if (ns->regs.row >= ns->geom.pgnum - ns->geom.pgsec
1626 			|| (ns->regs.row & ~(ns->geom.secsz - 1))) {
1627 			NS_ERR("do_state_action: wrong sector address (%#x)\n", ns->regs.row);
1628 			return -1;
1629 		}
1630 
1631 		ns->regs.row = (ns->regs.row <<
1632 				8 * (ns->geom.pgaddrbytes - ns->geom.secaddrbytes)) | ns->regs.column;
1633 		ns->regs.column = 0;
1634 
1635 		erase_block_no = ns->regs.row >> (ns->geom.secshift - ns->geom.pgshift);
1636 
1637 		NS_DBG("do_state_action: erase sector at address %#x, off = %d\n",
1638 				ns->regs.row, NS_RAW_OFFSET(ns));
1639 		NS_LOG("erase sector %u\n", erase_block_no);
1640 
1641 		ns_erase_sector(ns);
1642 
1643 		NS_MDELAY(erase_delay);
1644 
1645 		if (erase_block_wear)
1646 			ns_update_wear(erase_block_no);
1647 
1648 		if (ns_erase_error(erase_block_no)) {
1649 			NS_WARN("simulating erase failure in erase block %u\n", erase_block_no);
1650 			return -1;
1651 		}
1652 
1653 		break;
1654 
1655 	case ACTION_PRGPAGE:
1656 		/*
1657 		 * Program page - move internal buffer data to the page.
1658 		 */
1659 
1660 		if (ns->lines.wp) {
1661 			NS_WARN("do_state_action: device is write-protected, programm\n");
1662 			return -1;
1663 		}
1664 
1665 		num = ns->geom.pgszoob - NS_PAGE_BYTE_SHIFT(ns);
1666 		if (num != ns->regs.count) {
1667 			NS_ERR("do_state_action: too few bytes were input (%d instead of %d)\n",
1668 					ns->regs.count, num);
1669 			return -1;
1670 		}
1671 
1672 		if (ns_prog_page(ns, num) == -1)
1673 			return -1;
1674 
1675 		page_no = ns->regs.row;
1676 
1677 		NS_DBG("do_state_action: copy %d bytes from int buf to (%#x, %#x), raw off = %d\n",
1678 			num, ns->regs.row, ns->regs.column, NS_RAW_OFFSET(ns) + ns->regs.off);
1679 		NS_LOG("programm page %d\n", ns->regs.row);
1680 
1681 		NS_UDELAY(programm_delay);
1682 		NS_UDELAY(output_cycle * ns->geom.pgsz / 1000 / busdiv);
1683 
1684 		if (ns_write_error(page_no)) {
1685 			NS_WARN("simulating write failure in page %u\n", page_no);
1686 			return -1;
1687 		}
1688 
1689 		break;
1690 
1691 	case ACTION_ZEROOFF:
1692 		NS_DBG("do_state_action: set internal offset to 0\n");
1693 		ns->regs.off = 0;
1694 		break;
1695 
1696 	case ACTION_HALFOFF:
1697 		if (!(ns->options & OPT_PAGE512_8BIT)) {
1698 			NS_ERR("do_state_action: BUG! can't skip half of page for non-512"
1699 				"byte page size 8x chips\n");
1700 			return -1;
1701 		}
1702 		NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz/2);
1703 		ns->regs.off = ns->geom.pgsz/2;
1704 		break;
1705 
1706 	case ACTION_OOBOFF:
1707 		NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz);
1708 		ns->regs.off = ns->geom.pgsz;
1709 		break;
1710 
1711 	default:
1712 		NS_DBG("do_state_action: BUG! unknown action\n");
1713 	}
1714 
1715 	return 0;
1716 }
1717 
1718 /*
1719  * Switch simulator's state.
1720  */
1721 static void ns_switch_state(struct nandsim *ns)
1722 {
1723 	if (ns->op) {
1724 		/*
1725 		 * The current operation have already been identified.
1726 		 * Just follow the states chain.
1727 		 */
1728 
1729 		ns->stateidx += 1;
1730 		ns->state = ns->nxstate;
1731 		ns->nxstate = ns->op[ns->stateidx + 1];
1732 
1733 		NS_DBG("switch_state: operation is known, switch to the next state, "
1734 			"state: %s, nxstate: %s\n",
1735 		       ns_get_state_name(ns->state),
1736 		       ns_get_state_name(ns->nxstate));
1737 	} else {
1738 		/*
1739 		 * We don't yet know which operation we perform.
1740 		 * Try to identify it.
1741 		 */
1742 
1743 		/*
1744 		 *  The only event causing the switch_state function to
1745 		 *  be called with yet unknown operation is new command.
1746 		 */
1747 		ns->state = ns_get_state_by_command(ns->regs.command);
1748 
1749 		NS_DBG("switch_state: operation is unknown, try to find it\n");
1750 
1751 		if (ns_find_operation(ns, 0))
1752 			return;
1753 	}
1754 
1755 	/* See, whether we need to do some action */
1756 	if ((ns->state & ACTION_MASK) &&
1757 	    ns_do_state_action(ns, ns->state) < 0) {
1758 		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1759 		return;
1760 	}
1761 
1762 	/* For 16x devices column means the page offset in words */
1763 	if ((ns->nxstate & STATE_ADDR_MASK) && ns->busw == 16) {
1764 		NS_DBG("switch_state: double the column number for 16x device\n");
1765 		ns->regs.column <<= 1;
1766 	}
1767 
1768 	if (NS_STATE(ns->nxstate) == STATE_READY) {
1769 		/*
1770 		 * The current state is the last. Return to STATE_READY
1771 		 */
1772 
1773 		u_char status = NS_STATUS_OK(ns);
1774 
1775 		/* In case of data states, see if all bytes were input/output */
1776 		if ((ns->state & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK))
1777 			&& ns->regs.count != ns->regs.num) {
1778 			NS_WARN("switch_state: not all bytes were processed, %d left\n",
1779 					ns->regs.num - ns->regs.count);
1780 			status = NS_STATUS_FAILED(ns);
1781 		}
1782 
1783 		NS_DBG("switch_state: operation complete, switch to STATE_READY state\n");
1784 
1785 		ns_switch_to_ready_state(ns, status);
1786 
1787 		return;
1788 	} else if (ns->nxstate & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK)) {
1789 		/*
1790 		 * If the next state is data input/output, switch to it now
1791 		 */
1792 
1793 		ns->state      = ns->nxstate;
1794 		ns->nxstate    = ns->op[++ns->stateidx + 1];
1795 		ns->regs.num   = ns->regs.count = 0;
1796 
1797 		NS_DBG("switch_state: the next state is data I/O, switch, "
1798 			"state: %s, nxstate: %s\n",
1799 		       ns_get_state_name(ns->state),
1800 		       ns_get_state_name(ns->nxstate));
1801 
1802 		/*
1803 		 * Set the internal register to the count of bytes which
1804 		 * are expected to be input or output
1805 		 */
1806 		switch (NS_STATE(ns->state)) {
1807 			case STATE_DATAIN:
1808 			case STATE_DATAOUT:
1809 				ns->regs.num = ns->geom.pgszoob - NS_PAGE_BYTE_SHIFT(ns);
1810 				break;
1811 
1812 			case STATE_DATAOUT_ID:
1813 				ns->regs.num = ns->geom.idbytes;
1814 				break;
1815 
1816 			case STATE_DATAOUT_STATUS:
1817 				ns->regs.count = ns->regs.num = 0;
1818 				break;
1819 
1820 			default:
1821 				NS_ERR("switch_state: BUG! unknown data state\n");
1822 		}
1823 
1824 	} else if (ns->nxstate & STATE_ADDR_MASK) {
1825 		/*
1826 		 * If the next state is address input, set the internal
1827 		 * register to the number of expected address bytes
1828 		 */
1829 
1830 		ns->regs.count = 0;
1831 
1832 		switch (NS_STATE(ns->nxstate)) {
1833 			case STATE_ADDR_PAGE:
1834 				ns->regs.num = ns->geom.pgaddrbytes;
1835 
1836 				break;
1837 			case STATE_ADDR_SEC:
1838 				ns->regs.num = ns->geom.secaddrbytes;
1839 				break;
1840 
1841 			case STATE_ADDR_ZERO:
1842 				ns->regs.num = 1;
1843 				break;
1844 
1845 			case STATE_ADDR_COLUMN:
1846 				/* Column address is always 2 bytes */
1847 				ns->regs.num = ns->geom.pgaddrbytes - ns->geom.secaddrbytes;
1848 				break;
1849 
1850 			default:
1851 				NS_ERR("switch_state: BUG! unknown address state\n");
1852 		}
1853 	} else {
1854 		/*
1855 		 * Just reset internal counters.
1856 		 */
1857 
1858 		ns->regs.num = 0;
1859 		ns->regs.count = 0;
1860 	}
1861 }
1862 
1863 static u_char ns_nand_read_byte(struct nand_chip *chip)
1864 {
1865 	struct nandsim *ns = nand_get_controller_data(chip);
1866 	u_char outb = 0x00;
1867 
1868 	/* Sanity and correctness checks */
1869 	if (!ns->lines.ce) {
1870 		NS_ERR("read_byte: chip is disabled, return %#x\n", (uint)outb);
1871 		return outb;
1872 	}
1873 	if (ns->lines.ale || ns->lines.cle) {
1874 		NS_ERR("read_byte: ALE or CLE pin is high, return %#x\n", (uint)outb);
1875 		return outb;
1876 	}
1877 	if (!(ns->state & STATE_DATAOUT_MASK)) {
1878 		NS_WARN("read_byte: unexpected data output cycle, state is %s return %#x\n",
1879 			ns_get_state_name(ns->state), (uint)outb);
1880 		return outb;
1881 	}
1882 
1883 	/* Status register may be read as many times as it is wanted */
1884 	if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS) {
1885 		NS_DBG("read_byte: return %#x status\n", ns->regs.status);
1886 		return ns->regs.status;
1887 	}
1888 
1889 	/* Check if there is any data in the internal buffer which may be read */
1890 	if (ns->regs.count == ns->regs.num) {
1891 		NS_WARN("read_byte: no more data to output, return %#x\n", (uint)outb);
1892 		return outb;
1893 	}
1894 
1895 	switch (NS_STATE(ns->state)) {
1896 		case STATE_DATAOUT:
1897 			if (ns->busw == 8) {
1898 				outb = ns->buf.byte[ns->regs.count];
1899 				ns->regs.count += 1;
1900 			} else {
1901 				outb = (u_char)cpu_to_le16(ns->buf.word[ns->regs.count >> 1]);
1902 				ns->regs.count += 2;
1903 			}
1904 			break;
1905 		case STATE_DATAOUT_ID:
1906 			NS_DBG("read_byte: read ID byte %d, total = %d\n", ns->regs.count, ns->regs.num);
1907 			outb = ns->ids[ns->regs.count];
1908 			ns->regs.count += 1;
1909 			break;
1910 		default:
1911 			BUG();
1912 	}
1913 
1914 	if (ns->regs.count == ns->regs.num) {
1915 		NS_DBG("read_byte: all bytes were read\n");
1916 
1917 		if (NS_STATE(ns->nxstate) == STATE_READY)
1918 			ns_switch_state(ns);
1919 	}
1920 
1921 	return outb;
1922 }
1923 
1924 static void ns_nand_write_byte(struct nand_chip *chip, u_char byte)
1925 {
1926 	struct nandsim *ns = nand_get_controller_data(chip);
1927 
1928 	/* Sanity and correctness checks */
1929 	if (!ns->lines.ce) {
1930 		NS_ERR("write_byte: chip is disabled, ignore write\n");
1931 		return;
1932 	}
1933 	if (ns->lines.ale && ns->lines.cle) {
1934 		NS_ERR("write_byte: ALE and CLE pins are high simultaneously, ignore write\n");
1935 		return;
1936 	}
1937 
1938 	if (ns->lines.cle == 1) {
1939 		/*
1940 		 * The byte written is a command.
1941 		 */
1942 
1943 		if (byte == NAND_CMD_RESET) {
1944 			NS_LOG("reset chip\n");
1945 			ns_switch_to_ready_state(ns, NS_STATUS_OK(ns));
1946 			return;
1947 		}
1948 
1949 		/* Check that the command byte is correct */
1950 		if (ns_check_command(byte)) {
1951 			NS_ERR("write_byte: unknown command %#x\n", (uint)byte);
1952 			return;
1953 		}
1954 
1955 		if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS
1956 			|| NS_STATE(ns->state) == STATE_DATAOUT) {
1957 			int row = ns->regs.row;
1958 
1959 			ns_switch_state(ns);
1960 			if (byte == NAND_CMD_RNDOUT)
1961 				ns->regs.row = row;
1962 		}
1963 
1964 		/* Check if chip is expecting command */
1965 		if (NS_STATE(ns->nxstate) != STATE_UNKNOWN && !(ns->nxstate & STATE_CMD_MASK)) {
1966 			/* Do not warn if only 2 id bytes are read */
1967 			if (!(ns->regs.command == NAND_CMD_READID &&
1968 			    NS_STATE(ns->state) == STATE_DATAOUT_ID && ns->regs.count == 2)) {
1969 				/*
1970 				 * We are in situation when something else (not command)
1971 				 * was expected but command was input. In this case ignore
1972 				 * previous command(s)/state(s) and accept the last one.
1973 				 */
1974 				NS_WARN("write_byte: command (%#x) wasn't expected, expected state is %s, ignore previous states\n",
1975 					(uint)byte,
1976 					ns_get_state_name(ns->nxstate));
1977 			}
1978 			ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1979 		}
1980 
1981 		NS_DBG("command byte corresponding to %s state accepted\n",
1982 			ns_get_state_name(ns_get_state_by_command(byte)));
1983 		ns->regs.command = byte;
1984 		ns_switch_state(ns);
1985 
1986 	} else if (ns->lines.ale == 1) {
1987 		/*
1988 		 * The byte written is an address.
1989 		 */
1990 
1991 		if (NS_STATE(ns->nxstate) == STATE_UNKNOWN) {
1992 
1993 			NS_DBG("write_byte: operation isn't known yet, identify it\n");
1994 
1995 			if (ns_find_operation(ns, 1) < 0)
1996 				return;
1997 
1998 			if ((ns->state & ACTION_MASK) &&
1999 			    ns_do_state_action(ns, ns->state) < 0) {
2000 				ns_switch_to_ready_state(ns,
2001 							 NS_STATUS_FAILED(ns));
2002 				return;
2003 			}
2004 
2005 			ns->regs.count = 0;
2006 			switch (NS_STATE(ns->nxstate)) {
2007 				case STATE_ADDR_PAGE:
2008 					ns->regs.num = ns->geom.pgaddrbytes;
2009 					break;
2010 				case STATE_ADDR_SEC:
2011 					ns->regs.num = ns->geom.secaddrbytes;
2012 					break;
2013 				case STATE_ADDR_ZERO:
2014 					ns->regs.num = 1;
2015 					break;
2016 				default:
2017 					BUG();
2018 			}
2019 		}
2020 
2021 		/* Check that chip is expecting address */
2022 		if (!(ns->nxstate & STATE_ADDR_MASK)) {
2023 			NS_ERR("write_byte: address (%#x) isn't expected, expected state is %s, switch to STATE_READY\n",
2024 			       (uint)byte, ns_get_state_name(ns->nxstate));
2025 			ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2026 			return;
2027 		}
2028 
2029 		/* Check if this is expected byte */
2030 		if (ns->regs.count == ns->regs.num) {
2031 			NS_ERR("write_byte: no more address bytes expected\n");
2032 			ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2033 			return;
2034 		}
2035 
2036 		ns_accept_addr_byte(ns, byte);
2037 
2038 		ns->regs.count += 1;
2039 
2040 		NS_DBG("write_byte: address byte %#x was accepted (%d bytes input, %d expected)\n",
2041 				(uint)byte, ns->regs.count, ns->regs.num);
2042 
2043 		if (ns->regs.count == ns->regs.num) {
2044 			NS_DBG("address (%#x, %#x) is accepted\n", ns->regs.row, ns->regs.column);
2045 			ns_switch_state(ns);
2046 		}
2047 
2048 	} else {
2049 		/*
2050 		 * The byte written is an input data.
2051 		 */
2052 
2053 		/* Check that chip is expecting data input */
2054 		if (!(ns->state & STATE_DATAIN_MASK)) {
2055 			NS_ERR("write_byte: data input (%#x) isn't expected, state is %s, switch to %s\n",
2056 			       (uint)byte, ns_get_state_name(ns->state),
2057 			       ns_get_state_name(STATE_READY));
2058 			ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2059 			return;
2060 		}
2061 
2062 		/* Check if this is expected byte */
2063 		if (ns->regs.count == ns->regs.num) {
2064 			NS_WARN("write_byte: %u input bytes has already been accepted, ignore write\n",
2065 					ns->regs.num);
2066 			return;
2067 		}
2068 
2069 		if (ns->busw == 8) {
2070 			ns->buf.byte[ns->regs.count] = byte;
2071 			ns->regs.count += 1;
2072 		} else {
2073 			ns->buf.word[ns->regs.count >> 1] = cpu_to_le16((uint16_t)byte);
2074 			ns->regs.count += 2;
2075 		}
2076 	}
2077 
2078 	return;
2079 }
2080 
2081 static void ns_nand_write_buf(struct nand_chip *chip, const u_char *buf,
2082 			      int len)
2083 {
2084 	struct nandsim *ns = nand_get_controller_data(chip);
2085 
2086 	/* Check that chip is expecting data input */
2087 	if (!(ns->state & STATE_DATAIN_MASK)) {
2088 		NS_ERR("write_buf: data input isn't expected, state is %s, switch to STATE_READY\n",
2089 		       ns_get_state_name(ns->state));
2090 		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2091 		return;
2092 	}
2093 
2094 	/* Check if these are expected bytes */
2095 	if (ns->regs.count + len > ns->regs.num) {
2096 		NS_ERR("write_buf: too many input bytes\n");
2097 		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2098 		return;
2099 	}
2100 
2101 	memcpy(ns->buf.byte + ns->regs.count, buf, len);
2102 	ns->regs.count += len;
2103 
2104 	if (ns->regs.count == ns->regs.num) {
2105 		NS_DBG("write_buf: %d bytes were written\n", ns->regs.count);
2106 	}
2107 }
2108 
2109 static void ns_nand_read_buf(struct nand_chip *chip, u_char *buf, int len)
2110 {
2111 	struct nandsim *ns = nand_get_controller_data(chip);
2112 
2113 	/* Sanity and correctness checks */
2114 	if (!ns->lines.ce) {
2115 		NS_ERR("read_buf: chip is disabled\n");
2116 		return;
2117 	}
2118 	if (ns->lines.ale || ns->lines.cle) {
2119 		NS_ERR("read_buf: ALE or CLE pin is high\n");
2120 		return;
2121 	}
2122 	if (!(ns->state & STATE_DATAOUT_MASK)) {
2123 		NS_WARN("read_buf: unexpected data output cycle, current state is %s\n",
2124 			ns_get_state_name(ns->state));
2125 		return;
2126 	}
2127 
2128 	if (NS_STATE(ns->state) != STATE_DATAOUT) {
2129 		int i;
2130 
2131 		for (i = 0; i < len; i++)
2132 			buf[i] = ns_nand_read_byte(chip);
2133 
2134 		return;
2135 	}
2136 
2137 	/* Check if these are expected bytes */
2138 	if (ns->regs.count + len > ns->regs.num) {
2139 		NS_ERR("read_buf: too many bytes to read\n");
2140 		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2141 		return;
2142 	}
2143 
2144 	memcpy(buf, ns->buf.byte + ns->regs.count, len);
2145 	ns->regs.count += len;
2146 
2147 	if (ns->regs.count == ns->regs.num) {
2148 		if (NS_STATE(ns->nxstate) == STATE_READY)
2149 			ns_switch_state(ns);
2150 	}
2151 
2152 	return;
2153 }
2154 
2155 static int ns_exec_op(struct nand_chip *chip, const struct nand_operation *op,
2156 		      bool check_only)
2157 {
2158 	int i;
2159 	unsigned int op_id;
2160 	const struct nand_op_instr *instr = NULL;
2161 	struct nandsim *ns = nand_get_controller_data(chip);
2162 
2163 	if (check_only)
2164 		return 0;
2165 
2166 	ns->lines.ce = 1;
2167 
2168 	for (op_id = 0; op_id < op->ninstrs; op_id++) {
2169 		instr = &op->instrs[op_id];
2170 		ns->lines.cle = 0;
2171 		ns->lines.ale = 0;
2172 
2173 		switch (instr->type) {
2174 		case NAND_OP_CMD_INSTR:
2175 			ns->lines.cle = 1;
2176 			ns_nand_write_byte(chip, instr->ctx.cmd.opcode);
2177 			break;
2178 		case NAND_OP_ADDR_INSTR:
2179 			ns->lines.ale = 1;
2180 			for (i = 0; i < instr->ctx.addr.naddrs; i++)
2181 				ns_nand_write_byte(chip, instr->ctx.addr.addrs[i]);
2182 			break;
2183 		case NAND_OP_DATA_IN_INSTR:
2184 			ns_nand_read_buf(chip, instr->ctx.data.buf.in, instr->ctx.data.len);
2185 			break;
2186 		case NAND_OP_DATA_OUT_INSTR:
2187 			ns_nand_write_buf(chip, instr->ctx.data.buf.out, instr->ctx.data.len);
2188 			break;
2189 		case NAND_OP_WAITRDY_INSTR:
2190 			/* we are always ready */
2191 			break;
2192 		}
2193 	}
2194 
2195 	return 0;
2196 }
2197 
2198 static int ns_attach_chip(struct nand_chip *chip)
2199 {
2200 	unsigned int eccsteps, eccbytes;
2201 
2202 	chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
2203 	chip->ecc.algo = bch ? NAND_ECC_ALGO_BCH : NAND_ECC_ALGO_HAMMING;
2204 
2205 	if (!bch)
2206 		return 0;
2207 
2208 	if (!IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_BCH)) {
2209 		NS_ERR("BCH ECC support is disabled\n");
2210 		return -EINVAL;
2211 	}
2212 
2213 	/* Use 512-byte ecc blocks */
2214 	eccsteps = nsmtd->writesize / 512;
2215 	eccbytes = ((bch * 13) + 7) / 8;
2216 
2217 	/* Do not bother supporting small page devices */
2218 	if (nsmtd->oobsize < 64 || !eccsteps) {
2219 		NS_ERR("BCH not available on small page devices\n");
2220 		return -EINVAL;
2221 	}
2222 
2223 	if (((eccbytes * eccsteps) + 2) > nsmtd->oobsize) {
2224 		NS_ERR("Invalid BCH value %u\n", bch);
2225 		return -EINVAL;
2226 	}
2227 
2228 	chip->ecc.size = 512;
2229 	chip->ecc.strength = bch;
2230 	chip->ecc.bytes = eccbytes;
2231 
2232 	NS_INFO("Using %u-bit/%u bytes BCH ECC\n", bch, chip->ecc.size);
2233 
2234 	return 0;
2235 }
2236 
2237 static const struct nand_controller_ops ns_controller_ops = {
2238 	.attach_chip = ns_attach_chip,
2239 	.exec_op = ns_exec_op,
2240 };
2241 
2242 /*
2243  * Module initialization function
2244  */
2245 static int __init ns_init_module(void)
2246 {
2247 	struct list_head *pos, *n;
2248 	struct nand_chip *chip;
2249 	struct nandsim *ns;
2250 	int ret;
2251 
2252 	if (bus_width != 8 && bus_width != 16) {
2253 		NS_ERR("wrong bus width (%d), use only 8 or 16\n", bus_width);
2254 		return -EINVAL;
2255 	}
2256 
2257 	ns = kzalloc(sizeof(struct nandsim), GFP_KERNEL);
2258 	if (!ns) {
2259 		NS_ERR("unable to allocate core structures.\n");
2260 		return -ENOMEM;
2261 	}
2262 	chip	    = &ns->chip;
2263 	nsmtd       = nand_to_mtd(chip);
2264 	nand_set_controller_data(chip, (void *)ns);
2265 
2266 	/* The NAND_SKIP_BBTSCAN option is necessary for 'overridesize' */
2267 	/* and 'badblocks' parameters to work */
2268 	chip->options   |= NAND_SKIP_BBTSCAN;
2269 
2270 	switch (bbt) {
2271 	case 2:
2272 		chip->bbt_options |= NAND_BBT_NO_OOB;
2273 		fallthrough;
2274 	case 1:
2275 		chip->bbt_options |= NAND_BBT_USE_FLASH;
2276 		fallthrough;
2277 	case 0:
2278 		break;
2279 	default:
2280 		NS_ERR("bbt has to be 0..2\n");
2281 		ret = -EINVAL;
2282 		goto free_ns_struct;
2283 	}
2284 	/*
2285 	 * Perform minimum nandsim structure initialization to handle
2286 	 * the initial ID read command correctly
2287 	 */
2288 	if (id_bytes[6] != 0xFF || id_bytes[7] != 0xFF)
2289 		ns->geom.idbytes = 8;
2290 	else if (id_bytes[4] != 0xFF || id_bytes[5] != 0xFF)
2291 		ns->geom.idbytes = 6;
2292 	else if (id_bytes[2] != 0xFF || id_bytes[3] != 0xFF)
2293 		ns->geom.idbytes = 4;
2294 	else
2295 		ns->geom.idbytes = 2;
2296 	ns->regs.status = NS_STATUS_OK(ns);
2297 	ns->nxstate = STATE_UNKNOWN;
2298 	ns->options |= OPT_PAGE512; /* temporary value */
2299 	memcpy(ns->ids, id_bytes, sizeof(ns->ids));
2300 	if (bus_width == 16) {
2301 		ns->busw = 16;
2302 		chip->options |= NAND_BUSWIDTH_16;
2303 	}
2304 
2305 	nsmtd->owner = THIS_MODULE;
2306 
2307 	ret = ns_parse_weakblocks();
2308 	if (ret)
2309 		goto free_ns_struct;
2310 
2311 	ret = ns_parse_weakpages();
2312 	if (ret)
2313 		goto free_wb_list;
2314 
2315 	ret = ns_parse_gravepages();
2316 	if (ret)
2317 		goto free_wp_list;
2318 
2319 	nand_controller_init(&ns->base);
2320 	ns->base.ops = &ns_controller_ops;
2321 	chip->controller = &ns->base;
2322 
2323 	ret = nand_scan(chip, 1);
2324 	if (ret) {
2325 		NS_ERR("Could not scan NAND Simulator device\n");
2326 		goto free_gp_list;
2327 	}
2328 
2329 	if (overridesize) {
2330 		uint64_t new_size = (uint64_t)nsmtd->erasesize << overridesize;
2331 		struct nand_memory_organization *memorg;
2332 		u64 targetsize;
2333 
2334 		memorg = nanddev_get_memorg(&chip->base);
2335 
2336 		if (new_size >> overridesize != nsmtd->erasesize) {
2337 			NS_ERR("overridesize is too big\n");
2338 			ret = -EINVAL;
2339 			goto cleanup_nand;
2340 		}
2341 
2342 		/* N.B. This relies on nand_scan not doing anything with the size before we change it */
2343 		nsmtd->size = new_size;
2344 		memorg->eraseblocks_per_lun = 1 << overridesize;
2345 		targetsize = nanddev_target_size(&chip->base);
2346 		chip->chip_shift = ffs(nsmtd->erasesize) + overridesize - 1;
2347 		chip->pagemask = (targetsize >> chip->page_shift) - 1;
2348 	}
2349 
2350 	ret = ns_setup_wear_reporting(nsmtd);
2351 	if (ret)
2352 		goto cleanup_nand;
2353 
2354 	ret = ns_init(nsmtd);
2355 	if (ret)
2356 		goto free_ebw;
2357 
2358 	ret = nand_create_bbt(chip);
2359 	if (ret)
2360 		goto free_ns_object;
2361 
2362 	ret = ns_parse_badblocks(ns, nsmtd);
2363 	if (ret)
2364 		goto free_ns_object;
2365 
2366 	/* Register NAND partitions */
2367 	ret = mtd_device_register(nsmtd, &ns->partitions[0], ns->nbparts);
2368 	if (ret)
2369 		goto free_ns_object;
2370 
2371 	ret = ns_debugfs_create(ns);
2372 	if (ret)
2373 		goto unregister_mtd;
2374 
2375         return 0;
2376 
2377 unregister_mtd:
2378 	WARN_ON(mtd_device_unregister(nsmtd));
2379 free_ns_object:
2380 	ns_free(ns);
2381 free_ebw:
2382 	kfree(erase_block_wear);
2383 cleanup_nand:
2384 	nand_cleanup(chip);
2385 free_gp_list:
2386 	list_for_each_safe(pos, n, &grave_pages) {
2387 		list_del(pos);
2388 		kfree(list_entry(pos, struct grave_page, list));
2389 	}
2390 free_wp_list:
2391 	list_for_each_safe(pos, n, &weak_pages) {
2392 		list_del(pos);
2393 		kfree(list_entry(pos, struct weak_page, list));
2394 	}
2395 free_wb_list:
2396 	list_for_each_safe(pos, n, &weak_blocks) {
2397 		list_del(pos);
2398 		kfree(list_entry(pos, struct weak_block, list));
2399 	}
2400 free_ns_struct:
2401 	kfree(ns);
2402 
2403 	return ret;
2404 }
2405 
2406 module_init(ns_init_module);
2407 
2408 /*
2409  * Module clean-up function
2410  */
2411 static void __exit ns_cleanup_module(void)
2412 {
2413 	struct nand_chip *chip = mtd_to_nand(nsmtd);
2414 	struct nandsim *ns = nand_get_controller_data(chip);
2415 	struct list_head *pos, *n;
2416 
2417 	ns_debugfs_remove(ns);
2418 	WARN_ON(mtd_device_unregister(nsmtd));
2419 	ns_free(ns);
2420 	kfree(erase_block_wear);
2421 	nand_cleanup(chip);
2422 
2423 	list_for_each_safe(pos, n, &grave_pages) {
2424 		list_del(pos);
2425 		kfree(list_entry(pos, struct grave_page, list));
2426 	}
2427 
2428 	list_for_each_safe(pos, n, &weak_pages) {
2429 		list_del(pos);
2430 		kfree(list_entry(pos, struct weak_page, list));
2431 	}
2432 
2433 	list_for_each_safe(pos, n, &weak_blocks) {
2434 		list_del(pos);
2435 		kfree(list_entry(pos, struct weak_block, list));
2436 	}
2437 
2438 	kfree(ns);
2439 }
2440 
2441 module_exit(ns_cleanup_module);
2442 
2443 MODULE_LICENSE ("GPL");
2444 MODULE_AUTHOR ("Artem B. Bityuckiy");
2445 MODULE_DESCRIPTION ("The NAND flash simulator");
2446