xref: /openbmc/linux/drivers/mtd/nand/raw/nandsim.c (revision 20e2fc42)
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/nand_bch.h>
27 #include <linux/mtd/partitions.h>
28 #include <linux/delay.h>
29 #include <linux/list.h>
30 #include <linux/random.h>
31 #include <linux/sched.h>
32 #include <linux/sched/mm.h>
33 #include <linux/fs.h>
34 #include <linux/pagemap.h>
35 #include <linux/seq_file.h>
36 #include <linux/debugfs.h>
37 
38 /* Default simulator parameters values */
39 #if !defined(CONFIG_NANDSIM_FIRST_ID_BYTE)  || \
40     !defined(CONFIG_NANDSIM_SECOND_ID_BYTE) || \
41     !defined(CONFIG_NANDSIM_THIRD_ID_BYTE)  || \
42     !defined(CONFIG_NANDSIM_FOURTH_ID_BYTE)
43 #define CONFIG_NANDSIM_FIRST_ID_BYTE  0x98
44 #define CONFIG_NANDSIM_SECOND_ID_BYTE 0x39
45 #define CONFIG_NANDSIM_THIRD_ID_BYTE  0xFF /* No byte */
46 #define CONFIG_NANDSIM_FOURTH_ID_BYTE 0xFF /* No byte */
47 #endif
48 
49 #ifndef CONFIG_NANDSIM_ACCESS_DELAY
50 #define CONFIG_NANDSIM_ACCESS_DELAY 25
51 #endif
52 #ifndef CONFIG_NANDSIM_PROGRAMM_DELAY
53 #define CONFIG_NANDSIM_PROGRAMM_DELAY 200
54 #endif
55 #ifndef CONFIG_NANDSIM_ERASE_DELAY
56 #define CONFIG_NANDSIM_ERASE_DELAY 2
57 #endif
58 #ifndef CONFIG_NANDSIM_OUTPUT_CYCLE
59 #define CONFIG_NANDSIM_OUTPUT_CYCLE 40
60 #endif
61 #ifndef CONFIG_NANDSIM_INPUT_CYCLE
62 #define CONFIG_NANDSIM_INPUT_CYCLE  50
63 #endif
64 #ifndef CONFIG_NANDSIM_BUS_WIDTH
65 #define CONFIG_NANDSIM_BUS_WIDTH  8
66 #endif
67 #ifndef CONFIG_NANDSIM_DO_DELAYS
68 #define CONFIG_NANDSIM_DO_DELAYS  0
69 #endif
70 #ifndef CONFIG_NANDSIM_LOG
71 #define CONFIG_NANDSIM_LOG        0
72 #endif
73 #ifndef CONFIG_NANDSIM_DBG
74 #define CONFIG_NANDSIM_DBG        0
75 #endif
76 #ifndef CONFIG_NANDSIM_MAX_PARTS
77 #define CONFIG_NANDSIM_MAX_PARTS  32
78 #endif
79 
80 static uint access_delay   = CONFIG_NANDSIM_ACCESS_DELAY;
81 static uint programm_delay = CONFIG_NANDSIM_PROGRAMM_DELAY;
82 static uint erase_delay    = CONFIG_NANDSIM_ERASE_DELAY;
83 static uint output_cycle   = CONFIG_NANDSIM_OUTPUT_CYCLE;
84 static uint input_cycle    = CONFIG_NANDSIM_INPUT_CYCLE;
85 static uint bus_width      = CONFIG_NANDSIM_BUS_WIDTH;
86 static uint do_delays      = CONFIG_NANDSIM_DO_DELAYS;
87 static uint log            = CONFIG_NANDSIM_LOG;
88 static uint dbg            = CONFIG_NANDSIM_DBG;
89 static unsigned long parts[CONFIG_NANDSIM_MAX_PARTS];
90 static unsigned int parts_num;
91 static char *badblocks = NULL;
92 static char *weakblocks = NULL;
93 static char *weakpages = NULL;
94 static unsigned int bitflips = 0;
95 static char *gravepages = NULL;
96 static unsigned int overridesize = 0;
97 static char *cache_file = NULL;
98 static unsigned int bbt;
99 static unsigned int bch;
100 static u_char id_bytes[8] = {
101 	[0] = CONFIG_NANDSIM_FIRST_ID_BYTE,
102 	[1] = CONFIG_NANDSIM_SECOND_ID_BYTE,
103 	[2] = CONFIG_NANDSIM_THIRD_ID_BYTE,
104 	[3] = CONFIG_NANDSIM_FOURTH_ID_BYTE,
105 	[4 ... 7] = 0xFF,
106 };
107 
108 module_param_array(id_bytes, byte, NULL, 0400);
109 module_param_named(first_id_byte, id_bytes[0], byte, 0400);
110 module_param_named(second_id_byte, id_bytes[1], byte, 0400);
111 module_param_named(third_id_byte, id_bytes[2], byte, 0400);
112 module_param_named(fourth_id_byte, id_bytes[3], byte, 0400);
113 module_param(access_delay,   uint, 0400);
114 module_param(programm_delay, uint, 0400);
115 module_param(erase_delay,    uint, 0400);
116 module_param(output_cycle,   uint, 0400);
117 module_param(input_cycle,    uint, 0400);
118 module_param(bus_width,      uint, 0400);
119 module_param(do_delays,      uint, 0400);
120 module_param(log,            uint, 0400);
121 module_param(dbg,            uint, 0400);
122 module_param_array(parts, ulong, &parts_num, 0400);
123 module_param(badblocks,      charp, 0400);
124 module_param(weakblocks,     charp, 0400);
125 module_param(weakpages,      charp, 0400);
126 module_param(bitflips,       uint, 0400);
127 module_param(gravepages,     charp, 0400);
128 module_param(overridesize,   uint, 0400);
129 module_param(cache_file,     charp, 0400);
130 module_param(bbt,	     uint, 0400);
131 module_param(bch,	     uint, 0400);
132 
133 MODULE_PARM_DESC(id_bytes,       "The ID bytes returned by NAND Flash 'read ID' command");
134 MODULE_PARM_DESC(first_id_byte,  "The first byte returned by NAND Flash 'read ID' command (manufacturer ID) (obsolete)");
135 MODULE_PARM_DESC(second_id_byte, "The second byte returned by NAND Flash 'read ID' command (chip ID) (obsolete)");
136 MODULE_PARM_DESC(third_id_byte,  "The third byte returned by NAND Flash 'read ID' command (obsolete)");
137 MODULE_PARM_DESC(fourth_id_byte, "The fourth byte returned by NAND Flash 'read ID' command (obsolete)");
138 MODULE_PARM_DESC(access_delay,   "Initial page access delay (microseconds)");
139 MODULE_PARM_DESC(programm_delay, "Page programm delay (microseconds");
140 MODULE_PARM_DESC(erase_delay,    "Sector erase delay (milliseconds)");
141 MODULE_PARM_DESC(output_cycle,   "Word output (from flash) time (nanoseconds)");
142 MODULE_PARM_DESC(input_cycle,    "Word input (to flash) time (nanoseconds)");
143 MODULE_PARM_DESC(bus_width,      "Chip's bus width (8- or 16-bit)");
144 MODULE_PARM_DESC(do_delays,      "Simulate NAND delays using busy-waits if not zero");
145 MODULE_PARM_DESC(log,            "Perform logging if not zero");
146 MODULE_PARM_DESC(dbg,            "Output debug information if not zero");
147 MODULE_PARM_DESC(parts,          "Partition sizes (in erase blocks) separated by commas");
148 /* Page and erase block positions for the following parameters are independent of any partitions */
149 MODULE_PARM_DESC(badblocks,      "Erase blocks that are initially marked bad, separated by commas");
150 MODULE_PARM_DESC(weakblocks,     "Weak erase blocks [: remaining erase cycles (defaults to 3)]"
151 				 " separated by commas e.g. 113:2 means eb 113"
152 				 " can be erased only twice before failing");
153 MODULE_PARM_DESC(weakpages,      "Weak pages [: maximum writes (defaults to 3)]"
154 				 " separated by commas e.g. 1401:2 means page 1401"
155 				 " can be written only twice before failing");
156 MODULE_PARM_DESC(bitflips,       "Maximum number of random bit flips per page (zero by default)");
157 MODULE_PARM_DESC(gravepages,     "Pages that lose data [: maximum reads (defaults to 3)]"
158 				 " separated by commas e.g. 1401:2 means page 1401"
159 				 " can be read only twice before failing");
160 MODULE_PARM_DESC(overridesize,   "Specifies the NAND Flash size overriding the ID bytes. "
161 				 "The size is specified in erase blocks and as the exponent of a power of two"
162 				 " e.g. 5 means a size of 32 erase blocks");
163 MODULE_PARM_DESC(cache_file,     "File to use to cache nand pages instead of memory");
164 MODULE_PARM_DESC(bbt,		 "0 OOB, 1 BBT with marker in OOB, 2 BBT with marker in data area");
165 MODULE_PARM_DESC(bch,		 "Enable BCH ecc and set how many bits should "
166 				 "be correctable in 512-byte blocks");
167 
168 /* The largest possible page size */
169 #define NS_LARGEST_PAGE_SIZE	4096
170 
171 /* Simulator's output macros (logging, debugging, warning, error) */
172 #define NS_LOG(args...) \
173 	do { if (log) pr_debug(" log: " args); } while(0)
174 #define NS_DBG(args...) \
175 	do { if (dbg) pr_debug(" debug: " args); } while(0)
176 #define NS_WARN(args...) \
177 	do { pr_warn(" warning: " args); } while(0)
178 #define NS_ERR(args...) \
179 	do { pr_err(" error: " args); } while(0)
180 #define NS_INFO(args...) \
181 	do { pr_info(" " args); } while(0)
182 
183 /* Busy-wait delay macros (microseconds, milliseconds) */
184 #define NS_UDELAY(us) \
185         do { if (do_delays) udelay(us); } while(0)
186 #define NS_MDELAY(us) \
187         do { if (do_delays) mdelay(us); } while(0)
188 
189 /* Is the nandsim structure initialized ? */
190 #define NS_IS_INITIALIZED(ns) ((ns)->geom.totsz != 0)
191 
192 /* Good operation completion status */
193 #define NS_STATUS_OK(ns) (NAND_STATUS_READY | (NAND_STATUS_WP * ((ns)->lines.wp == 0)))
194 
195 /* Operation failed completion status */
196 #define NS_STATUS_FAILED(ns) (NAND_STATUS_FAIL | NS_STATUS_OK(ns))
197 
198 /* Calculate the page offset in flash RAM image by (row, column) address */
199 #define NS_RAW_OFFSET(ns) \
200 	(((ns)->regs.row * (ns)->geom.pgszoob) + (ns)->regs.column)
201 
202 /* Calculate the OOB offset in flash RAM image by (row, column) address */
203 #define NS_RAW_OFFSET_OOB(ns) (NS_RAW_OFFSET(ns) + ns->geom.pgsz)
204 
205 /* After a command is input, the simulator goes to one of the following states */
206 #define STATE_CMD_READ0        0x00000001 /* read data from the beginning of page */
207 #define STATE_CMD_READ1        0x00000002 /* read data from the second half of page */
208 #define STATE_CMD_READSTART    0x00000003 /* read data second command (large page devices) */
209 #define STATE_CMD_PAGEPROG     0x00000004 /* start page program */
210 #define STATE_CMD_READOOB      0x00000005 /* read OOB area */
211 #define STATE_CMD_ERASE1       0x00000006 /* sector erase first command */
212 #define STATE_CMD_STATUS       0x00000007 /* read status */
213 #define STATE_CMD_SEQIN        0x00000009 /* sequential data input */
214 #define STATE_CMD_READID       0x0000000A /* read ID */
215 #define STATE_CMD_ERASE2       0x0000000B /* sector erase second command */
216 #define STATE_CMD_RESET        0x0000000C /* reset */
217 #define STATE_CMD_RNDOUT       0x0000000D /* random output command */
218 #define STATE_CMD_RNDOUTSTART  0x0000000E /* random output start command */
219 #define STATE_CMD_MASK         0x0000000F /* command states mask */
220 
221 /* After an address is input, the simulator goes to one of these states */
222 #define STATE_ADDR_PAGE        0x00000010 /* full (row, column) address is accepted */
223 #define STATE_ADDR_SEC         0x00000020 /* sector address was accepted */
224 #define STATE_ADDR_COLUMN      0x00000030 /* column address was accepted */
225 #define STATE_ADDR_ZERO        0x00000040 /* one byte zero address was accepted */
226 #define STATE_ADDR_MASK        0x00000070 /* address states mask */
227 
228 /* During data input/output the simulator is in these states */
229 #define STATE_DATAIN           0x00000100 /* waiting for data input */
230 #define STATE_DATAIN_MASK      0x00000100 /* data input states mask */
231 
232 #define STATE_DATAOUT          0x00001000 /* waiting for page data output */
233 #define STATE_DATAOUT_ID       0x00002000 /* waiting for ID bytes output */
234 #define STATE_DATAOUT_STATUS   0x00003000 /* waiting for status output */
235 #define STATE_DATAOUT_MASK     0x00007000 /* data output states mask */
236 
237 /* Previous operation is done, ready to accept new requests */
238 #define STATE_READY            0x00000000
239 
240 /* This state is used to mark that the next state isn't known yet */
241 #define STATE_UNKNOWN          0x10000000
242 
243 /* Simulator's actions bit masks */
244 #define ACTION_CPY       0x00100000 /* copy page/OOB to the internal buffer */
245 #define ACTION_PRGPAGE   0x00200000 /* program the internal buffer to flash */
246 #define ACTION_SECERASE  0x00300000 /* erase sector */
247 #define ACTION_ZEROOFF   0x00400000 /* don't add any offset to address */
248 #define ACTION_HALFOFF   0x00500000 /* add to address half of page */
249 #define ACTION_OOBOFF    0x00600000 /* add to address OOB offset */
250 #define ACTION_MASK      0x00700000 /* action mask */
251 
252 #define NS_OPER_NUM      13 /* Number of operations supported by the simulator */
253 #define NS_OPER_STATES   6  /* Maximum number of states in operation */
254 
255 #define OPT_ANY          0xFFFFFFFF /* any chip supports this operation */
256 #define OPT_PAGE512      0x00000002 /* 512-byte  page chips */
257 #define OPT_PAGE2048     0x00000008 /* 2048-byte page chips */
258 #define OPT_PAGE512_8BIT 0x00000040 /* 512-byte page chips with 8-bit bus width */
259 #define OPT_PAGE4096     0x00000080 /* 4096-byte page chips */
260 #define OPT_LARGEPAGE    (OPT_PAGE2048 | OPT_PAGE4096) /* 2048 & 4096-byte page chips */
261 #define OPT_SMALLPAGE    (OPT_PAGE512) /* 512-byte page chips */
262 
263 /* Remove action bits from state */
264 #define NS_STATE(x) ((x) & ~ACTION_MASK)
265 
266 /*
267  * Maximum previous states which need to be saved. Currently saving is
268  * only needed for page program operation with preceded read command
269  * (which is only valid for 512-byte pages).
270  */
271 #define NS_MAX_PREVSTATES 1
272 
273 /* Maximum page cache pages needed to read or write a NAND page to the cache_file */
274 #define NS_MAX_HELD_PAGES 16
275 
276 /*
277  * A union to represent flash memory contents and flash buffer.
278  */
279 union ns_mem {
280 	u_char *byte;    /* for byte access */
281 	uint16_t *word;  /* for 16-bit word access */
282 };
283 
284 /*
285  * The structure which describes all the internal simulator data.
286  */
287 struct nandsim {
288 	struct nand_chip chip;
289 	struct nand_controller base;
290 	struct mtd_partition partitions[CONFIG_NANDSIM_MAX_PARTS];
291 	unsigned int nbparts;
292 
293 	uint busw;              /* flash chip bus width (8 or 16) */
294 	u_char ids[8];          /* chip's ID bytes */
295 	uint32_t options;       /* chip's characteristic bits */
296 	uint32_t state;         /* current chip state */
297 	uint32_t nxstate;       /* next expected state */
298 
299 	uint32_t *op;           /* current operation, NULL operations isn't known yet  */
300 	uint32_t pstates[NS_MAX_PREVSTATES]; /* previous states */
301 	uint16_t npstates;      /* number of previous states saved */
302 	uint16_t stateidx;      /* current state index */
303 
304 	/* The simulated NAND flash pages array */
305 	union ns_mem *pages;
306 
307 	/* Slab allocator for nand pages */
308 	struct kmem_cache *nand_pages_slab;
309 
310 	/* Internal buffer of page + OOB size bytes */
311 	union ns_mem buf;
312 
313 	/* NAND flash "geometry" */
314 	struct {
315 		uint64_t totsz;     /* total flash size, bytes */
316 		uint32_t secsz;     /* flash sector (erase block) size, bytes */
317 		uint pgsz;          /* NAND flash page size, bytes */
318 		uint oobsz;         /* page OOB area size, bytes */
319 		uint64_t totszoob;  /* total flash size including OOB, bytes */
320 		uint pgszoob;       /* page size including OOB , bytes*/
321 		uint secszoob;      /* sector size including OOB, bytes */
322 		uint pgnum;         /* total number of pages */
323 		uint pgsec;         /* number of pages per sector */
324 		uint secshift;      /* bits number in sector size */
325 		uint pgshift;       /* bits number in page size */
326 		uint pgaddrbytes;   /* bytes per page address */
327 		uint secaddrbytes;  /* bytes per sector address */
328 		uint idbytes;       /* the number ID bytes that this chip outputs */
329 	} geom;
330 
331 	/* NAND flash internal registers */
332 	struct {
333 		unsigned command; /* the command register */
334 		u_char   status;  /* the status register */
335 		uint     row;     /* the page number */
336 		uint     column;  /* the offset within page */
337 		uint     count;   /* internal counter */
338 		uint     num;     /* number of bytes which must be processed */
339 		uint     off;     /* fixed page offset */
340 	} regs;
341 
342 	/* NAND flash lines state */
343         struct {
344                 int ce;  /* chip Enable */
345                 int cle; /* command Latch Enable */
346                 int ale; /* address Latch Enable */
347                 int wp;  /* write Protect */
348         } lines;
349 
350 	/* Fields needed when using a cache file */
351 	struct file *cfile; /* Open file */
352 	unsigned long *pages_written; /* Which pages have been written */
353 	void *file_buf;
354 	struct page *held_pages[NS_MAX_HELD_PAGES];
355 	int held_cnt;
356 };
357 
358 /*
359  * Operations array. To perform any operation the simulator must pass
360  * through the correspondent states chain.
361  */
362 static struct nandsim_operations {
363 	uint32_t reqopts;  /* options which are required to perform the operation */
364 	uint32_t states[NS_OPER_STATES]; /* operation's states */
365 } ops[NS_OPER_NUM] = {
366 	/* Read page + OOB from the beginning */
367 	{OPT_SMALLPAGE, {STATE_CMD_READ0 | ACTION_ZEROOFF, STATE_ADDR_PAGE | ACTION_CPY,
368 			STATE_DATAOUT, STATE_READY}},
369 	/* Read page + OOB from the second half */
370 	{OPT_PAGE512_8BIT, {STATE_CMD_READ1 | ACTION_HALFOFF, STATE_ADDR_PAGE | ACTION_CPY,
371 			STATE_DATAOUT, STATE_READY}},
372 	/* Read OOB */
373 	{OPT_SMALLPAGE, {STATE_CMD_READOOB | ACTION_OOBOFF, STATE_ADDR_PAGE | ACTION_CPY,
374 			STATE_DATAOUT, STATE_READY}},
375 	/* Program page starting from the beginning */
376 	{OPT_ANY, {STATE_CMD_SEQIN, STATE_ADDR_PAGE, STATE_DATAIN,
377 			STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
378 	/* Program page starting from the beginning */
379 	{OPT_SMALLPAGE, {STATE_CMD_READ0, STATE_CMD_SEQIN | ACTION_ZEROOFF, STATE_ADDR_PAGE,
380 			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
381 	/* Program page starting from the second half */
382 	{OPT_PAGE512, {STATE_CMD_READ1, STATE_CMD_SEQIN | ACTION_HALFOFF, STATE_ADDR_PAGE,
383 			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
384 	/* Program OOB */
385 	{OPT_SMALLPAGE, {STATE_CMD_READOOB, STATE_CMD_SEQIN | ACTION_OOBOFF, STATE_ADDR_PAGE,
386 			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
387 	/* Erase sector */
388 	{OPT_ANY, {STATE_CMD_ERASE1, STATE_ADDR_SEC, STATE_CMD_ERASE2 | ACTION_SECERASE, STATE_READY}},
389 	/* Read status */
390 	{OPT_ANY, {STATE_CMD_STATUS, STATE_DATAOUT_STATUS, STATE_READY}},
391 	/* Read ID */
392 	{OPT_ANY, {STATE_CMD_READID, STATE_ADDR_ZERO, STATE_DATAOUT_ID, STATE_READY}},
393 	/* Large page devices read page */
394 	{OPT_LARGEPAGE, {STATE_CMD_READ0, STATE_ADDR_PAGE, STATE_CMD_READSTART | ACTION_CPY,
395 			       STATE_DATAOUT, STATE_READY}},
396 	/* Large page devices random page read */
397 	{OPT_LARGEPAGE, {STATE_CMD_RNDOUT, STATE_ADDR_COLUMN, STATE_CMD_RNDOUTSTART | ACTION_CPY,
398 			       STATE_DATAOUT, STATE_READY}},
399 };
400 
401 struct weak_block {
402 	struct list_head list;
403 	unsigned int erase_block_no;
404 	unsigned int max_erases;
405 	unsigned int erases_done;
406 };
407 
408 static LIST_HEAD(weak_blocks);
409 
410 struct weak_page {
411 	struct list_head list;
412 	unsigned int page_no;
413 	unsigned int max_writes;
414 	unsigned int writes_done;
415 };
416 
417 static LIST_HEAD(weak_pages);
418 
419 struct grave_page {
420 	struct list_head list;
421 	unsigned int page_no;
422 	unsigned int max_reads;
423 	unsigned int reads_done;
424 };
425 
426 static LIST_HEAD(grave_pages);
427 
428 static unsigned long *erase_block_wear = NULL;
429 static unsigned int wear_eb_count = 0;
430 static unsigned long total_wear = 0;
431 
432 /* MTD structure for NAND controller */
433 static struct mtd_info *nsmtd;
434 
435 static int nandsim_show(struct seq_file *m, void *private)
436 {
437 	unsigned long wmin = -1, wmax = 0, avg;
438 	unsigned long deciles[10], decile_max[10], tot = 0;
439 	unsigned int i;
440 
441 	/* Calc wear stats */
442 	for (i = 0; i < wear_eb_count; ++i) {
443 		unsigned long wear = erase_block_wear[i];
444 		if (wear < wmin)
445 			wmin = wear;
446 		if (wear > wmax)
447 			wmax = wear;
448 		tot += wear;
449 	}
450 
451 	for (i = 0; i < 9; ++i) {
452 		deciles[i] = 0;
453 		decile_max[i] = (wmax * (i + 1) + 5) / 10;
454 	}
455 	deciles[9] = 0;
456 	decile_max[9] = wmax;
457 	for (i = 0; i < wear_eb_count; ++i) {
458 		int d;
459 		unsigned long wear = erase_block_wear[i];
460 		for (d = 0; d < 10; ++d)
461 			if (wear <= decile_max[d]) {
462 				deciles[d] += 1;
463 				break;
464 			}
465 	}
466 	avg = tot / wear_eb_count;
467 
468 	/* Output wear report */
469 	seq_printf(m, "Total numbers of erases:  %lu\n", tot);
470 	seq_printf(m, "Number of erase blocks:   %u\n", wear_eb_count);
471 	seq_printf(m, "Average number of erases: %lu\n", avg);
472 	seq_printf(m, "Maximum number of erases: %lu\n", wmax);
473 	seq_printf(m, "Minimum number of erases: %lu\n", wmin);
474 	for (i = 0; i < 10; ++i) {
475 		unsigned long from = (i ? decile_max[i - 1] + 1 : 0);
476 		if (from > decile_max[i])
477 			continue;
478 		seq_printf(m, "Number of ebs with erase counts from %lu to %lu : %lu\n",
479 			from,
480 			decile_max[i],
481 			deciles[i]);
482 	}
483 
484 	return 0;
485 }
486 DEFINE_SHOW_ATTRIBUTE(nandsim);
487 
488 /**
489  * nandsim_debugfs_create - initialize debugfs
490  * @dev: nandsim device description object
491  *
492  * This function creates all debugfs files for UBI device @ubi. Returns zero in
493  * case of success and a negative error code in case of failure.
494  */
495 static int nandsim_debugfs_create(struct nandsim *dev)
496 {
497 	struct dentry *root = nsmtd->dbg.dfs_dir;
498 	struct dentry *dent;
499 
500 	/*
501 	 * Just skip debugfs initialization when the debugfs directory is
502 	 * missing.
503 	 */
504 	if (IS_ERR_OR_NULL(root)) {
505 		if (IS_ENABLED(CONFIG_DEBUG_FS) &&
506 		    !IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER))
507 			NS_WARN("CONFIG_MTD_PARTITIONED_MASTER must be enabled to expose debugfs stuff\n");
508 		return 0;
509 	}
510 
511 	dent = debugfs_create_file("nandsim_wear_report", S_IRUSR,
512 				   root, dev, &nandsim_fops);
513 	if (IS_ERR_OR_NULL(dent)) {
514 		NS_ERR("cannot create \"nandsim_wear_report\" debugfs entry\n");
515 		return -1;
516 	}
517 
518 	return 0;
519 }
520 
521 /*
522  * Allocate array of page pointers, create slab allocation for an array
523  * and initialize the array by NULL pointers.
524  *
525  * RETURNS: 0 if success, -ENOMEM if memory alloc fails.
526  */
527 static int __init alloc_device(struct nandsim *ns)
528 {
529 	struct file *cfile;
530 	int i, err;
531 
532 	if (cache_file) {
533 		cfile = filp_open(cache_file, O_CREAT | O_RDWR | O_LARGEFILE, 0600);
534 		if (IS_ERR(cfile))
535 			return PTR_ERR(cfile);
536 		if (!(cfile->f_mode & FMODE_CAN_READ)) {
537 			NS_ERR("alloc_device: cache file not readable\n");
538 			err = -EINVAL;
539 			goto err_close;
540 		}
541 		if (!(cfile->f_mode & FMODE_CAN_WRITE)) {
542 			NS_ERR("alloc_device: cache file not writeable\n");
543 			err = -EINVAL;
544 			goto err_close;
545 		}
546 		ns->pages_written =
547 			vzalloc(array_size(sizeof(unsigned long),
548 					   BITS_TO_LONGS(ns->geom.pgnum)));
549 		if (!ns->pages_written) {
550 			NS_ERR("alloc_device: unable to allocate pages written array\n");
551 			err = -ENOMEM;
552 			goto err_close;
553 		}
554 		ns->file_buf = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
555 		if (!ns->file_buf) {
556 			NS_ERR("alloc_device: unable to allocate file buf\n");
557 			err = -ENOMEM;
558 			goto err_free;
559 		}
560 		ns->cfile = cfile;
561 		return 0;
562 	}
563 
564 	ns->pages = vmalloc(array_size(sizeof(union ns_mem), ns->geom.pgnum));
565 	if (!ns->pages) {
566 		NS_ERR("alloc_device: unable to allocate page array\n");
567 		return -ENOMEM;
568 	}
569 	for (i = 0; i < ns->geom.pgnum; i++) {
570 		ns->pages[i].byte = NULL;
571 	}
572 	ns->nand_pages_slab = kmem_cache_create("nandsim",
573 						ns->geom.pgszoob, 0, 0, NULL);
574 	if (!ns->nand_pages_slab) {
575 		NS_ERR("cache_create: unable to create kmem_cache\n");
576 		return -ENOMEM;
577 	}
578 
579 	return 0;
580 
581 err_free:
582 	vfree(ns->pages_written);
583 err_close:
584 	filp_close(cfile, NULL);
585 	return err;
586 }
587 
588 /*
589  * Free any allocated pages, and free the array of page pointers.
590  */
591 static void free_device(struct nandsim *ns)
592 {
593 	int i;
594 
595 	if (ns->cfile) {
596 		kfree(ns->file_buf);
597 		vfree(ns->pages_written);
598 		filp_close(ns->cfile, NULL);
599 		return;
600 	}
601 
602 	if (ns->pages) {
603 		for (i = 0; i < ns->geom.pgnum; i++) {
604 			if (ns->pages[i].byte)
605 				kmem_cache_free(ns->nand_pages_slab,
606 						ns->pages[i].byte);
607 		}
608 		kmem_cache_destroy(ns->nand_pages_slab);
609 		vfree(ns->pages);
610 	}
611 }
612 
613 static char __init *get_partition_name(int i)
614 {
615 	return kasprintf(GFP_KERNEL, "NAND simulator partition %d", i);
616 }
617 
618 /*
619  * Initialize the nandsim structure.
620  *
621  * RETURNS: 0 if success, -ERRNO if failure.
622  */
623 static int __init init_nandsim(struct mtd_info *mtd)
624 {
625 	struct nand_chip *chip = mtd_to_nand(mtd);
626 	struct nandsim   *ns   = nand_get_controller_data(chip);
627 	int i, ret = 0;
628 	uint64_t remains;
629 	uint64_t next_offset;
630 
631 	if (NS_IS_INITIALIZED(ns)) {
632 		NS_ERR("init_nandsim: nandsim is already initialized\n");
633 		return -EIO;
634 	}
635 
636 	/* Initialize the NAND flash parameters */
637 	ns->busw = chip->options & NAND_BUSWIDTH_16 ? 16 : 8;
638 	ns->geom.totsz    = mtd->size;
639 	ns->geom.pgsz     = mtd->writesize;
640 	ns->geom.oobsz    = mtd->oobsize;
641 	ns->geom.secsz    = mtd->erasesize;
642 	ns->geom.pgszoob  = ns->geom.pgsz + ns->geom.oobsz;
643 	ns->geom.pgnum    = div_u64(ns->geom.totsz, ns->geom.pgsz);
644 	ns->geom.totszoob = ns->geom.totsz + (uint64_t)ns->geom.pgnum * ns->geom.oobsz;
645 	ns->geom.secshift = ffs(ns->geom.secsz) - 1;
646 	ns->geom.pgshift  = chip->page_shift;
647 	ns->geom.pgsec    = ns->geom.secsz / ns->geom.pgsz;
648 	ns->geom.secszoob = ns->geom.secsz + ns->geom.oobsz * ns->geom.pgsec;
649 	ns->options = 0;
650 
651 	if (ns->geom.pgsz == 512) {
652 		ns->options |= OPT_PAGE512;
653 		if (ns->busw == 8)
654 			ns->options |= OPT_PAGE512_8BIT;
655 	} else if (ns->geom.pgsz == 2048) {
656 		ns->options |= OPT_PAGE2048;
657 	} else if (ns->geom.pgsz == 4096) {
658 		ns->options |= OPT_PAGE4096;
659 	} else {
660 		NS_ERR("init_nandsim: unknown page size %u\n", ns->geom.pgsz);
661 		return -EIO;
662 	}
663 
664 	if (ns->options & OPT_SMALLPAGE) {
665 		if (ns->geom.totsz <= (32 << 20)) {
666 			ns->geom.pgaddrbytes  = 3;
667 			ns->geom.secaddrbytes = 2;
668 		} else {
669 			ns->geom.pgaddrbytes  = 4;
670 			ns->geom.secaddrbytes = 3;
671 		}
672 	} else {
673 		if (ns->geom.totsz <= (128 << 20)) {
674 			ns->geom.pgaddrbytes  = 4;
675 			ns->geom.secaddrbytes = 2;
676 		} else {
677 			ns->geom.pgaddrbytes  = 5;
678 			ns->geom.secaddrbytes = 3;
679 		}
680 	}
681 
682 	/* Fill the partition_info structure */
683 	if (parts_num > ARRAY_SIZE(ns->partitions)) {
684 		NS_ERR("too many partitions.\n");
685 		return -EINVAL;
686 	}
687 	remains = ns->geom.totsz;
688 	next_offset = 0;
689 	for (i = 0; i < parts_num; ++i) {
690 		uint64_t part_sz = (uint64_t)parts[i] * ns->geom.secsz;
691 
692 		if (!part_sz || part_sz > remains) {
693 			NS_ERR("bad partition size.\n");
694 			return -EINVAL;
695 		}
696 		ns->partitions[i].name   = get_partition_name(i);
697 		if (!ns->partitions[i].name) {
698 			NS_ERR("unable to allocate memory.\n");
699 			return -ENOMEM;
700 		}
701 		ns->partitions[i].offset = next_offset;
702 		ns->partitions[i].size   = part_sz;
703 		next_offset += ns->partitions[i].size;
704 		remains -= ns->partitions[i].size;
705 	}
706 	ns->nbparts = parts_num;
707 	if (remains) {
708 		if (parts_num + 1 > ARRAY_SIZE(ns->partitions)) {
709 			NS_ERR("too many partitions.\n");
710 			return -EINVAL;
711 		}
712 		ns->partitions[i].name   = get_partition_name(i);
713 		if (!ns->partitions[i].name) {
714 			NS_ERR("unable to allocate memory.\n");
715 			return -ENOMEM;
716 		}
717 		ns->partitions[i].offset = next_offset;
718 		ns->partitions[i].size   = remains;
719 		ns->nbparts += 1;
720 	}
721 
722 	if (ns->busw == 16)
723 		NS_WARN("16-bit flashes support wasn't tested\n");
724 
725 	printk("flash size: %llu MiB\n",
726 			(unsigned long long)ns->geom.totsz >> 20);
727 	printk("page size: %u bytes\n",         ns->geom.pgsz);
728 	printk("OOB area size: %u bytes\n",     ns->geom.oobsz);
729 	printk("sector size: %u KiB\n",         ns->geom.secsz >> 10);
730 	printk("pages number: %u\n",            ns->geom.pgnum);
731 	printk("pages per sector: %u\n",        ns->geom.pgsec);
732 	printk("bus width: %u\n",               ns->busw);
733 	printk("bits in sector size: %u\n",     ns->geom.secshift);
734 	printk("bits in page size: %u\n",       ns->geom.pgshift);
735 	printk("bits in OOB size: %u\n",	ffs(ns->geom.oobsz) - 1);
736 	printk("flash size with OOB: %llu KiB\n",
737 			(unsigned long long)ns->geom.totszoob >> 10);
738 	printk("page address bytes: %u\n",      ns->geom.pgaddrbytes);
739 	printk("sector address bytes: %u\n",    ns->geom.secaddrbytes);
740 	printk("options: %#x\n",                ns->options);
741 
742 	if ((ret = alloc_device(ns)) != 0)
743 		return ret;
744 
745 	/* Allocate / initialize the internal buffer */
746 	ns->buf.byte = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
747 	if (!ns->buf.byte) {
748 		NS_ERR("init_nandsim: unable to allocate %u bytes for the internal buffer\n",
749 			ns->geom.pgszoob);
750 		return -ENOMEM;
751 	}
752 	memset(ns->buf.byte, 0xFF, ns->geom.pgszoob);
753 
754 	return 0;
755 }
756 
757 /*
758  * Free the nandsim structure.
759  */
760 static void free_nandsim(struct nandsim *ns)
761 {
762 	kfree(ns->buf.byte);
763 	free_device(ns);
764 
765 	return;
766 }
767 
768 static int parse_badblocks(struct nandsim *ns, struct mtd_info *mtd)
769 {
770 	char *w;
771 	int zero_ok;
772 	unsigned int erase_block_no;
773 	loff_t offset;
774 
775 	if (!badblocks)
776 		return 0;
777 	w = badblocks;
778 	do {
779 		zero_ok = (*w == '0' ? 1 : 0);
780 		erase_block_no = simple_strtoul(w, &w, 0);
781 		if (!zero_ok && !erase_block_no) {
782 			NS_ERR("invalid badblocks.\n");
783 			return -EINVAL;
784 		}
785 		offset = (loff_t)erase_block_no * ns->geom.secsz;
786 		if (mtd_block_markbad(mtd, offset)) {
787 			NS_ERR("invalid badblocks.\n");
788 			return -EINVAL;
789 		}
790 		if (*w == ',')
791 			w += 1;
792 	} while (*w);
793 	return 0;
794 }
795 
796 static int parse_weakblocks(void)
797 {
798 	char *w;
799 	int zero_ok;
800 	unsigned int erase_block_no;
801 	unsigned int max_erases;
802 	struct weak_block *wb;
803 
804 	if (!weakblocks)
805 		return 0;
806 	w = weakblocks;
807 	do {
808 		zero_ok = (*w == '0' ? 1 : 0);
809 		erase_block_no = simple_strtoul(w, &w, 0);
810 		if (!zero_ok && !erase_block_no) {
811 			NS_ERR("invalid weakblocks.\n");
812 			return -EINVAL;
813 		}
814 		max_erases = 3;
815 		if (*w == ':') {
816 			w += 1;
817 			max_erases = simple_strtoul(w, &w, 0);
818 		}
819 		if (*w == ',')
820 			w += 1;
821 		wb = kzalloc(sizeof(*wb), GFP_KERNEL);
822 		if (!wb) {
823 			NS_ERR("unable to allocate memory.\n");
824 			return -ENOMEM;
825 		}
826 		wb->erase_block_no = erase_block_no;
827 		wb->max_erases = max_erases;
828 		list_add(&wb->list, &weak_blocks);
829 	} while (*w);
830 	return 0;
831 }
832 
833 static int erase_error(unsigned int erase_block_no)
834 {
835 	struct weak_block *wb;
836 
837 	list_for_each_entry(wb, &weak_blocks, list)
838 		if (wb->erase_block_no == erase_block_no) {
839 			if (wb->erases_done >= wb->max_erases)
840 				return 1;
841 			wb->erases_done += 1;
842 			return 0;
843 		}
844 	return 0;
845 }
846 
847 static int parse_weakpages(void)
848 {
849 	char *w;
850 	int zero_ok;
851 	unsigned int page_no;
852 	unsigned int max_writes;
853 	struct weak_page *wp;
854 
855 	if (!weakpages)
856 		return 0;
857 	w = weakpages;
858 	do {
859 		zero_ok = (*w == '0' ? 1 : 0);
860 		page_no = simple_strtoul(w, &w, 0);
861 		if (!zero_ok && !page_no) {
862 			NS_ERR("invalid weakpages.\n");
863 			return -EINVAL;
864 		}
865 		max_writes = 3;
866 		if (*w == ':') {
867 			w += 1;
868 			max_writes = simple_strtoul(w, &w, 0);
869 		}
870 		if (*w == ',')
871 			w += 1;
872 		wp = kzalloc(sizeof(*wp), GFP_KERNEL);
873 		if (!wp) {
874 			NS_ERR("unable to allocate memory.\n");
875 			return -ENOMEM;
876 		}
877 		wp->page_no = page_no;
878 		wp->max_writes = max_writes;
879 		list_add(&wp->list, &weak_pages);
880 	} while (*w);
881 	return 0;
882 }
883 
884 static int write_error(unsigned int page_no)
885 {
886 	struct weak_page *wp;
887 
888 	list_for_each_entry(wp, &weak_pages, list)
889 		if (wp->page_no == page_no) {
890 			if (wp->writes_done >= wp->max_writes)
891 				return 1;
892 			wp->writes_done += 1;
893 			return 0;
894 		}
895 	return 0;
896 }
897 
898 static int parse_gravepages(void)
899 {
900 	char *g;
901 	int zero_ok;
902 	unsigned int page_no;
903 	unsigned int max_reads;
904 	struct grave_page *gp;
905 
906 	if (!gravepages)
907 		return 0;
908 	g = gravepages;
909 	do {
910 		zero_ok = (*g == '0' ? 1 : 0);
911 		page_no = simple_strtoul(g, &g, 0);
912 		if (!zero_ok && !page_no) {
913 			NS_ERR("invalid gravepagess.\n");
914 			return -EINVAL;
915 		}
916 		max_reads = 3;
917 		if (*g == ':') {
918 			g += 1;
919 			max_reads = simple_strtoul(g, &g, 0);
920 		}
921 		if (*g == ',')
922 			g += 1;
923 		gp = kzalloc(sizeof(*gp), GFP_KERNEL);
924 		if (!gp) {
925 			NS_ERR("unable to allocate memory.\n");
926 			return -ENOMEM;
927 		}
928 		gp->page_no = page_no;
929 		gp->max_reads = max_reads;
930 		list_add(&gp->list, &grave_pages);
931 	} while (*g);
932 	return 0;
933 }
934 
935 static int read_error(unsigned int page_no)
936 {
937 	struct grave_page *gp;
938 
939 	list_for_each_entry(gp, &grave_pages, list)
940 		if (gp->page_no == page_no) {
941 			if (gp->reads_done >= gp->max_reads)
942 				return 1;
943 			gp->reads_done += 1;
944 			return 0;
945 		}
946 	return 0;
947 }
948 
949 static void free_lists(void)
950 {
951 	struct list_head *pos, *n;
952 	list_for_each_safe(pos, n, &weak_blocks) {
953 		list_del(pos);
954 		kfree(list_entry(pos, struct weak_block, list));
955 	}
956 	list_for_each_safe(pos, n, &weak_pages) {
957 		list_del(pos);
958 		kfree(list_entry(pos, struct weak_page, list));
959 	}
960 	list_for_each_safe(pos, n, &grave_pages) {
961 		list_del(pos);
962 		kfree(list_entry(pos, struct grave_page, list));
963 	}
964 	kfree(erase_block_wear);
965 }
966 
967 static int setup_wear_reporting(struct mtd_info *mtd)
968 {
969 	size_t mem;
970 
971 	wear_eb_count = div_u64(mtd->size, mtd->erasesize);
972 	mem = wear_eb_count * sizeof(unsigned long);
973 	if (mem / sizeof(unsigned long) != wear_eb_count) {
974 		NS_ERR("Too many erase blocks for wear reporting\n");
975 		return -ENOMEM;
976 	}
977 	erase_block_wear = kzalloc(mem, GFP_KERNEL);
978 	if (!erase_block_wear) {
979 		NS_ERR("Too many erase blocks for wear reporting\n");
980 		return -ENOMEM;
981 	}
982 	return 0;
983 }
984 
985 static void update_wear(unsigned int erase_block_no)
986 {
987 	if (!erase_block_wear)
988 		return;
989 	total_wear += 1;
990 	/*
991 	 * TODO: Notify this through a debugfs entry,
992 	 * instead of showing an error message.
993 	 */
994 	if (total_wear == 0)
995 		NS_ERR("Erase counter total overflow\n");
996 	erase_block_wear[erase_block_no] += 1;
997 	if (erase_block_wear[erase_block_no] == 0)
998 		NS_ERR("Erase counter overflow for erase block %u\n", erase_block_no);
999 }
1000 
1001 /*
1002  * Returns the string representation of 'state' state.
1003  */
1004 static char *get_state_name(uint32_t state)
1005 {
1006 	switch (NS_STATE(state)) {
1007 		case STATE_CMD_READ0:
1008 			return "STATE_CMD_READ0";
1009 		case STATE_CMD_READ1:
1010 			return "STATE_CMD_READ1";
1011 		case STATE_CMD_PAGEPROG:
1012 			return "STATE_CMD_PAGEPROG";
1013 		case STATE_CMD_READOOB:
1014 			return "STATE_CMD_READOOB";
1015 		case STATE_CMD_READSTART:
1016 			return "STATE_CMD_READSTART";
1017 		case STATE_CMD_ERASE1:
1018 			return "STATE_CMD_ERASE1";
1019 		case STATE_CMD_STATUS:
1020 			return "STATE_CMD_STATUS";
1021 		case STATE_CMD_SEQIN:
1022 			return "STATE_CMD_SEQIN";
1023 		case STATE_CMD_READID:
1024 			return "STATE_CMD_READID";
1025 		case STATE_CMD_ERASE2:
1026 			return "STATE_CMD_ERASE2";
1027 		case STATE_CMD_RESET:
1028 			return "STATE_CMD_RESET";
1029 		case STATE_CMD_RNDOUT:
1030 			return "STATE_CMD_RNDOUT";
1031 		case STATE_CMD_RNDOUTSTART:
1032 			return "STATE_CMD_RNDOUTSTART";
1033 		case STATE_ADDR_PAGE:
1034 			return "STATE_ADDR_PAGE";
1035 		case STATE_ADDR_SEC:
1036 			return "STATE_ADDR_SEC";
1037 		case STATE_ADDR_ZERO:
1038 			return "STATE_ADDR_ZERO";
1039 		case STATE_ADDR_COLUMN:
1040 			return "STATE_ADDR_COLUMN";
1041 		case STATE_DATAIN:
1042 			return "STATE_DATAIN";
1043 		case STATE_DATAOUT:
1044 			return "STATE_DATAOUT";
1045 		case STATE_DATAOUT_ID:
1046 			return "STATE_DATAOUT_ID";
1047 		case STATE_DATAOUT_STATUS:
1048 			return "STATE_DATAOUT_STATUS";
1049 		case STATE_READY:
1050 			return "STATE_READY";
1051 		case STATE_UNKNOWN:
1052 			return "STATE_UNKNOWN";
1053 	}
1054 
1055 	NS_ERR("get_state_name: unknown state, BUG\n");
1056 	return NULL;
1057 }
1058 
1059 /*
1060  * Check if command is valid.
1061  *
1062  * RETURNS: 1 if wrong command, 0 if right.
1063  */
1064 static int check_command(int cmd)
1065 {
1066 	switch (cmd) {
1067 
1068 	case NAND_CMD_READ0:
1069 	case NAND_CMD_READ1:
1070 	case NAND_CMD_READSTART:
1071 	case NAND_CMD_PAGEPROG:
1072 	case NAND_CMD_READOOB:
1073 	case NAND_CMD_ERASE1:
1074 	case NAND_CMD_STATUS:
1075 	case NAND_CMD_SEQIN:
1076 	case NAND_CMD_READID:
1077 	case NAND_CMD_ERASE2:
1078 	case NAND_CMD_RESET:
1079 	case NAND_CMD_RNDOUT:
1080 	case NAND_CMD_RNDOUTSTART:
1081 		return 0;
1082 
1083 	default:
1084 		return 1;
1085 	}
1086 }
1087 
1088 /*
1089  * Returns state after command is accepted by command number.
1090  */
1091 static uint32_t get_state_by_command(unsigned command)
1092 {
1093 	switch (command) {
1094 		case NAND_CMD_READ0:
1095 			return STATE_CMD_READ0;
1096 		case NAND_CMD_READ1:
1097 			return STATE_CMD_READ1;
1098 		case NAND_CMD_PAGEPROG:
1099 			return STATE_CMD_PAGEPROG;
1100 		case NAND_CMD_READSTART:
1101 			return STATE_CMD_READSTART;
1102 		case NAND_CMD_READOOB:
1103 			return STATE_CMD_READOOB;
1104 		case NAND_CMD_ERASE1:
1105 			return STATE_CMD_ERASE1;
1106 		case NAND_CMD_STATUS:
1107 			return STATE_CMD_STATUS;
1108 		case NAND_CMD_SEQIN:
1109 			return STATE_CMD_SEQIN;
1110 		case NAND_CMD_READID:
1111 			return STATE_CMD_READID;
1112 		case NAND_CMD_ERASE2:
1113 			return STATE_CMD_ERASE2;
1114 		case NAND_CMD_RESET:
1115 			return STATE_CMD_RESET;
1116 		case NAND_CMD_RNDOUT:
1117 			return STATE_CMD_RNDOUT;
1118 		case NAND_CMD_RNDOUTSTART:
1119 			return STATE_CMD_RNDOUTSTART;
1120 	}
1121 
1122 	NS_ERR("get_state_by_command: unknown command, BUG\n");
1123 	return 0;
1124 }
1125 
1126 /*
1127  * Move an address byte to the correspondent internal register.
1128  */
1129 static inline void accept_addr_byte(struct nandsim *ns, u_char bt)
1130 {
1131 	uint byte = (uint)bt;
1132 
1133 	if (ns->regs.count < (ns->geom.pgaddrbytes - ns->geom.secaddrbytes))
1134 		ns->regs.column |= (byte << 8 * ns->regs.count);
1135 	else {
1136 		ns->regs.row |= (byte << 8 * (ns->regs.count -
1137 						ns->geom.pgaddrbytes +
1138 						ns->geom.secaddrbytes));
1139 	}
1140 
1141 	return;
1142 }
1143 
1144 /*
1145  * Switch to STATE_READY state.
1146  */
1147 static inline void switch_to_ready_state(struct nandsim *ns, u_char status)
1148 {
1149 	NS_DBG("switch_to_ready_state: switch to %s state\n", get_state_name(STATE_READY));
1150 
1151 	ns->state       = STATE_READY;
1152 	ns->nxstate     = STATE_UNKNOWN;
1153 	ns->op          = NULL;
1154 	ns->npstates    = 0;
1155 	ns->stateidx    = 0;
1156 	ns->regs.num    = 0;
1157 	ns->regs.count  = 0;
1158 	ns->regs.off    = 0;
1159 	ns->regs.row    = 0;
1160 	ns->regs.column = 0;
1161 	ns->regs.status = status;
1162 }
1163 
1164 /*
1165  * If the operation isn't known yet, try to find it in the global array
1166  * of supported operations.
1167  *
1168  * Operation can be unknown because of the following.
1169  *   1. New command was accepted and this is the first call to find the
1170  *      correspondent states chain. In this case ns->npstates = 0;
1171  *   2. There are several operations which begin with the same command(s)
1172  *      (for example program from the second half and read from the
1173  *      second half operations both begin with the READ1 command). In this
1174  *      case the ns->pstates[] array contains previous states.
1175  *
1176  * Thus, the function tries to find operation containing the following
1177  * states (if the 'flag' parameter is 0):
1178  *    ns->pstates[0], ... ns->pstates[ns->npstates], ns->state
1179  *
1180  * If (one and only one) matching operation is found, it is accepted (
1181  * ns->ops, ns->state, ns->nxstate are initialized, ns->npstate is
1182  * zeroed).
1183  *
1184  * If there are several matches, the current state is pushed to the
1185  * ns->pstates.
1186  *
1187  * The operation can be unknown only while commands are input to the chip.
1188  * As soon as address command is accepted, the operation must be known.
1189  * In such situation the function is called with 'flag' != 0, and the
1190  * operation is searched using the following pattern:
1191  *     ns->pstates[0], ... ns->pstates[ns->npstates], <address input>
1192  *
1193  * It is supposed that this pattern must either match one operation or
1194  * none. There can't be ambiguity in that case.
1195  *
1196  * If no matches found, the function does the following:
1197  *   1. if there are saved states present, try to ignore them and search
1198  *      again only using the last command. If nothing was found, switch
1199  *      to the STATE_READY state.
1200  *   2. if there are no saved states, switch to the STATE_READY state.
1201  *
1202  * RETURNS: -2 - no matched operations found.
1203  *          -1 - several matches.
1204  *           0 - operation is found.
1205  */
1206 static int find_operation(struct nandsim *ns, uint32_t flag)
1207 {
1208 	int opsfound = 0;
1209 	int i, j, idx = 0;
1210 
1211 	for (i = 0; i < NS_OPER_NUM; i++) {
1212 
1213 		int found = 1;
1214 
1215 		if (!(ns->options & ops[i].reqopts))
1216 			/* Ignore operations we can't perform */
1217 			continue;
1218 
1219 		if (flag) {
1220 			if (!(ops[i].states[ns->npstates] & STATE_ADDR_MASK))
1221 				continue;
1222 		} else {
1223 			if (NS_STATE(ns->state) != NS_STATE(ops[i].states[ns->npstates]))
1224 				continue;
1225 		}
1226 
1227 		for (j = 0; j < ns->npstates; j++)
1228 			if (NS_STATE(ops[i].states[j]) != NS_STATE(ns->pstates[j])
1229 				&& (ns->options & ops[idx].reqopts)) {
1230 				found = 0;
1231 				break;
1232 			}
1233 
1234 		if (found) {
1235 			idx = i;
1236 			opsfound += 1;
1237 		}
1238 	}
1239 
1240 	if (opsfound == 1) {
1241 		/* Exact match */
1242 		ns->op = &ops[idx].states[0];
1243 		if (flag) {
1244 			/*
1245 			 * In this case the find_operation function was
1246 			 * called when address has just began input. But it isn't
1247 			 * yet fully input and the current state must
1248 			 * not be one of STATE_ADDR_*, but the STATE_ADDR_*
1249 			 * state must be the next state (ns->nxstate).
1250 			 */
1251 			ns->stateidx = ns->npstates - 1;
1252 		} else {
1253 			ns->stateidx = ns->npstates;
1254 		}
1255 		ns->npstates = 0;
1256 		ns->state = ns->op[ns->stateidx];
1257 		ns->nxstate = ns->op[ns->stateidx + 1];
1258 		NS_DBG("find_operation: operation found, index: %d, state: %s, nxstate %s\n",
1259 				idx, get_state_name(ns->state), get_state_name(ns->nxstate));
1260 		return 0;
1261 	}
1262 
1263 	if (opsfound == 0) {
1264 		/* Nothing was found. Try to ignore previous commands (if any) and search again */
1265 		if (ns->npstates != 0) {
1266 			NS_DBG("find_operation: no operation found, try again with state %s\n",
1267 					get_state_name(ns->state));
1268 			ns->npstates = 0;
1269 			return find_operation(ns, 0);
1270 
1271 		}
1272 		NS_DBG("find_operation: no operations found\n");
1273 		switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1274 		return -2;
1275 	}
1276 
1277 	if (flag) {
1278 		/* This shouldn't happen */
1279 		NS_DBG("find_operation: BUG, operation must be known if address is input\n");
1280 		return -2;
1281 	}
1282 
1283 	NS_DBG("find_operation: there is still ambiguity\n");
1284 
1285 	ns->pstates[ns->npstates++] = ns->state;
1286 
1287 	return -1;
1288 }
1289 
1290 static void put_pages(struct nandsim *ns)
1291 {
1292 	int i;
1293 
1294 	for (i = 0; i < ns->held_cnt; i++)
1295 		put_page(ns->held_pages[i]);
1296 }
1297 
1298 /* Get page cache pages in advance to provide NOFS memory allocation */
1299 static int get_pages(struct nandsim *ns, struct file *file, size_t count, loff_t pos)
1300 {
1301 	pgoff_t index, start_index, end_index;
1302 	struct page *page;
1303 	struct address_space *mapping = file->f_mapping;
1304 
1305 	start_index = pos >> PAGE_SHIFT;
1306 	end_index = (pos + count - 1) >> PAGE_SHIFT;
1307 	if (end_index - start_index + 1 > NS_MAX_HELD_PAGES)
1308 		return -EINVAL;
1309 	ns->held_cnt = 0;
1310 	for (index = start_index; index <= end_index; index++) {
1311 		page = find_get_page(mapping, index);
1312 		if (page == NULL) {
1313 			page = find_or_create_page(mapping, index, GFP_NOFS);
1314 			if (page == NULL) {
1315 				write_inode_now(mapping->host, 1);
1316 				page = find_or_create_page(mapping, index, GFP_NOFS);
1317 			}
1318 			if (page == NULL) {
1319 				put_pages(ns);
1320 				return -ENOMEM;
1321 			}
1322 			unlock_page(page);
1323 		}
1324 		ns->held_pages[ns->held_cnt++] = page;
1325 	}
1326 	return 0;
1327 }
1328 
1329 static ssize_t read_file(struct nandsim *ns, struct file *file, void *buf, size_t count, loff_t pos)
1330 {
1331 	ssize_t tx;
1332 	int err;
1333 	unsigned int noreclaim_flag;
1334 
1335 	err = get_pages(ns, file, count, pos);
1336 	if (err)
1337 		return err;
1338 	noreclaim_flag = memalloc_noreclaim_save();
1339 	tx = kernel_read(file, buf, count, &pos);
1340 	memalloc_noreclaim_restore(noreclaim_flag);
1341 	put_pages(ns);
1342 	return tx;
1343 }
1344 
1345 static ssize_t write_file(struct nandsim *ns, struct file *file, void *buf, size_t count, loff_t pos)
1346 {
1347 	ssize_t tx;
1348 	int err;
1349 	unsigned int noreclaim_flag;
1350 
1351 	err = get_pages(ns, file, count, pos);
1352 	if (err)
1353 		return err;
1354 	noreclaim_flag = memalloc_noreclaim_save();
1355 	tx = kernel_write(file, buf, count, &pos);
1356 	memalloc_noreclaim_restore(noreclaim_flag);
1357 	put_pages(ns);
1358 	return tx;
1359 }
1360 
1361 /*
1362  * Returns a pointer to the current page.
1363  */
1364 static inline union ns_mem *NS_GET_PAGE(struct nandsim *ns)
1365 {
1366 	return &(ns->pages[ns->regs.row]);
1367 }
1368 
1369 /*
1370  * Retuns a pointer to the current byte, within the current page.
1371  */
1372 static inline u_char *NS_PAGE_BYTE_OFF(struct nandsim *ns)
1373 {
1374 	return NS_GET_PAGE(ns)->byte + ns->regs.column + ns->regs.off;
1375 }
1376 
1377 static int do_read_error(struct nandsim *ns, int num)
1378 {
1379 	unsigned int page_no = ns->regs.row;
1380 
1381 	if (read_error(page_no)) {
1382 		prandom_bytes(ns->buf.byte, num);
1383 		NS_WARN("simulating read error in page %u\n", page_no);
1384 		return 1;
1385 	}
1386 	return 0;
1387 }
1388 
1389 static void do_bit_flips(struct nandsim *ns, int num)
1390 {
1391 	if (bitflips && prandom_u32() < (1 << 22)) {
1392 		int flips = 1;
1393 		if (bitflips > 1)
1394 			flips = (prandom_u32() % (int) bitflips) + 1;
1395 		while (flips--) {
1396 			int pos = prandom_u32() % (num * 8);
1397 			ns->buf.byte[pos / 8] ^= (1 << (pos % 8));
1398 			NS_WARN("read_page: flipping bit %d in page %d "
1399 				"reading from %d ecc: corrected=%u failed=%u\n",
1400 				pos, ns->regs.row, ns->regs.column + ns->regs.off,
1401 				nsmtd->ecc_stats.corrected, nsmtd->ecc_stats.failed);
1402 		}
1403 	}
1404 }
1405 
1406 /*
1407  * Fill the NAND buffer with data read from the specified page.
1408  */
1409 static void read_page(struct nandsim *ns, int num)
1410 {
1411 	union ns_mem *mypage;
1412 
1413 	if (ns->cfile) {
1414 		if (!test_bit(ns->regs.row, ns->pages_written)) {
1415 			NS_DBG("read_page: page %d not written\n", ns->regs.row);
1416 			memset(ns->buf.byte, 0xFF, num);
1417 		} else {
1418 			loff_t pos;
1419 			ssize_t tx;
1420 
1421 			NS_DBG("read_page: page %d written, reading from %d\n",
1422 				ns->regs.row, ns->regs.column + ns->regs.off);
1423 			if (do_read_error(ns, num))
1424 				return;
1425 			pos = (loff_t)NS_RAW_OFFSET(ns) + ns->regs.off;
1426 			tx = read_file(ns, ns->cfile, ns->buf.byte, num, pos);
1427 			if (tx != num) {
1428 				NS_ERR("read_page: read error for page %d ret %ld\n", ns->regs.row, (long)tx);
1429 				return;
1430 			}
1431 			do_bit_flips(ns, num);
1432 		}
1433 		return;
1434 	}
1435 
1436 	mypage = NS_GET_PAGE(ns);
1437 	if (mypage->byte == NULL) {
1438 		NS_DBG("read_page: page %d not allocated\n", ns->regs.row);
1439 		memset(ns->buf.byte, 0xFF, num);
1440 	} else {
1441 		NS_DBG("read_page: page %d allocated, reading from %d\n",
1442 			ns->regs.row, ns->regs.column + ns->regs.off);
1443 		if (do_read_error(ns, num))
1444 			return;
1445 		memcpy(ns->buf.byte, NS_PAGE_BYTE_OFF(ns), num);
1446 		do_bit_flips(ns, num);
1447 	}
1448 }
1449 
1450 /*
1451  * Erase all pages in the specified sector.
1452  */
1453 static void erase_sector(struct nandsim *ns)
1454 {
1455 	union ns_mem *mypage;
1456 	int i;
1457 
1458 	if (ns->cfile) {
1459 		for (i = 0; i < ns->geom.pgsec; i++)
1460 			if (__test_and_clear_bit(ns->regs.row + i,
1461 						 ns->pages_written)) {
1462 				NS_DBG("erase_sector: freeing page %d\n", ns->regs.row + i);
1463 			}
1464 		return;
1465 	}
1466 
1467 	mypage = NS_GET_PAGE(ns);
1468 	for (i = 0; i < ns->geom.pgsec; i++) {
1469 		if (mypage->byte != NULL) {
1470 			NS_DBG("erase_sector: freeing page %d\n", ns->regs.row+i);
1471 			kmem_cache_free(ns->nand_pages_slab, mypage->byte);
1472 			mypage->byte = NULL;
1473 		}
1474 		mypage++;
1475 	}
1476 }
1477 
1478 /*
1479  * Program the specified page with the contents from the NAND buffer.
1480  */
1481 static int prog_page(struct nandsim *ns, int num)
1482 {
1483 	int i;
1484 	union ns_mem *mypage;
1485 	u_char *pg_off;
1486 
1487 	if (ns->cfile) {
1488 		loff_t off;
1489 		ssize_t tx;
1490 		int all;
1491 
1492 		NS_DBG("prog_page: writing page %d\n", ns->regs.row);
1493 		pg_off = ns->file_buf + ns->regs.column + ns->regs.off;
1494 		off = (loff_t)NS_RAW_OFFSET(ns) + ns->regs.off;
1495 		if (!test_bit(ns->regs.row, ns->pages_written)) {
1496 			all = 1;
1497 			memset(ns->file_buf, 0xff, ns->geom.pgszoob);
1498 		} else {
1499 			all = 0;
1500 			tx = read_file(ns, ns->cfile, pg_off, num, off);
1501 			if (tx != num) {
1502 				NS_ERR("prog_page: read error for page %d ret %ld\n", ns->regs.row, (long)tx);
1503 				return -1;
1504 			}
1505 		}
1506 		for (i = 0; i < num; i++)
1507 			pg_off[i] &= ns->buf.byte[i];
1508 		if (all) {
1509 			loff_t pos = (loff_t)ns->regs.row * ns->geom.pgszoob;
1510 			tx = write_file(ns, ns->cfile, ns->file_buf, ns->geom.pgszoob, pos);
1511 			if (tx != ns->geom.pgszoob) {
1512 				NS_ERR("prog_page: write error for page %d ret %ld\n", ns->regs.row, (long)tx);
1513 				return -1;
1514 			}
1515 			__set_bit(ns->regs.row, ns->pages_written);
1516 		} else {
1517 			tx = write_file(ns, ns->cfile, pg_off, num, off);
1518 			if (tx != num) {
1519 				NS_ERR("prog_page: write error for page %d ret %ld\n", ns->regs.row, (long)tx);
1520 				return -1;
1521 			}
1522 		}
1523 		return 0;
1524 	}
1525 
1526 	mypage = NS_GET_PAGE(ns);
1527 	if (mypage->byte == NULL) {
1528 		NS_DBG("prog_page: allocating page %d\n", ns->regs.row);
1529 		/*
1530 		 * We allocate memory with GFP_NOFS because a flash FS may
1531 		 * utilize this. If it is holding an FS lock, then gets here,
1532 		 * then kernel memory alloc runs writeback which goes to the FS
1533 		 * again and deadlocks. This was seen in practice.
1534 		 */
1535 		mypage->byte = kmem_cache_alloc(ns->nand_pages_slab, GFP_NOFS);
1536 		if (mypage->byte == NULL) {
1537 			NS_ERR("prog_page: error allocating memory for page %d\n", ns->regs.row);
1538 			return -1;
1539 		}
1540 		memset(mypage->byte, 0xFF, ns->geom.pgszoob);
1541 	}
1542 
1543 	pg_off = NS_PAGE_BYTE_OFF(ns);
1544 	for (i = 0; i < num; i++)
1545 		pg_off[i] &= ns->buf.byte[i];
1546 
1547 	return 0;
1548 }
1549 
1550 /*
1551  * If state has any action bit, perform this action.
1552  *
1553  * RETURNS: 0 if success, -1 if error.
1554  */
1555 static int do_state_action(struct nandsim *ns, uint32_t action)
1556 {
1557 	int num;
1558 	int busdiv = ns->busw == 8 ? 1 : 2;
1559 	unsigned int erase_block_no, page_no;
1560 
1561 	action &= ACTION_MASK;
1562 
1563 	/* Check that page address input is correct */
1564 	if (action != ACTION_SECERASE && ns->regs.row >= ns->geom.pgnum) {
1565 		NS_WARN("do_state_action: wrong page number (%#x)\n", ns->regs.row);
1566 		return -1;
1567 	}
1568 
1569 	switch (action) {
1570 
1571 	case ACTION_CPY:
1572 		/*
1573 		 * Copy page data to the internal buffer.
1574 		 */
1575 
1576 		/* Column shouldn't be very large */
1577 		if (ns->regs.column >= (ns->geom.pgszoob - ns->regs.off)) {
1578 			NS_ERR("do_state_action: column number is too large\n");
1579 			break;
1580 		}
1581 		num = ns->geom.pgszoob - ns->regs.off - ns->regs.column;
1582 		read_page(ns, num);
1583 
1584 		NS_DBG("do_state_action: (ACTION_CPY:) copy %d bytes to int buf, raw offset %d\n",
1585 			num, NS_RAW_OFFSET(ns) + ns->regs.off);
1586 
1587 		if (ns->regs.off == 0)
1588 			NS_LOG("read page %d\n", ns->regs.row);
1589 		else if (ns->regs.off < ns->geom.pgsz)
1590 			NS_LOG("read page %d (second half)\n", ns->regs.row);
1591 		else
1592 			NS_LOG("read OOB of page %d\n", ns->regs.row);
1593 
1594 		NS_UDELAY(access_delay);
1595 		NS_UDELAY(input_cycle * ns->geom.pgsz / 1000 / busdiv);
1596 
1597 		break;
1598 
1599 	case ACTION_SECERASE:
1600 		/*
1601 		 * Erase sector.
1602 		 */
1603 
1604 		if (ns->lines.wp) {
1605 			NS_ERR("do_state_action: device is write-protected, ignore sector erase\n");
1606 			return -1;
1607 		}
1608 
1609 		if (ns->regs.row >= ns->geom.pgnum - ns->geom.pgsec
1610 			|| (ns->regs.row & ~(ns->geom.secsz - 1))) {
1611 			NS_ERR("do_state_action: wrong sector address (%#x)\n", ns->regs.row);
1612 			return -1;
1613 		}
1614 
1615 		ns->regs.row = (ns->regs.row <<
1616 				8 * (ns->geom.pgaddrbytes - ns->geom.secaddrbytes)) | ns->regs.column;
1617 		ns->regs.column = 0;
1618 
1619 		erase_block_no = ns->regs.row >> (ns->geom.secshift - ns->geom.pgshift);
1620 
1621 		NS_DBG("do_state_action: erase sector at address %#x, off = %d\n",
1622 				ns->regs.row, NS_RAW_OFFSET(ns));
1623 		NS_LOG("erase sector %u\n", erase_block_no);
1624 
1625 		erase_sector(ns);
1626 
1627 		NS_MDELAY(erase_delay);
1628 
1629 		if (erase_block_wear)
1630 			update_wear(erase_block_no);
1631 
1632 		if (erase_error(erase_block_no)) {
1633 			NS_WARN("simulating erase failure in erase block %u\n", erase_block_no);
1634 			return -1;
1635 		}
1636 
1637 		break;
1638 
1639 	case ACTION_PRGPAGE:
1640 		/*
1641 		 * Program page - move internal buffer data to the page.
1642 		 */
1643 
1644 		if (ns->lines.wp) {
1645 			NS_WARN("do_state_action: device is write-protected, programm\n");
1646 			return -1;
1647 		}
1648 
1649 		num = ns->geom.pgszoob - ns->regs.off - ns->regs.column;
1650 		if (num != ns->regs.count) {
1651 			NS_ERR("do_state_action: too few bytes were input (%d instead of %d)\n",
1652 					ns->regs.count, num);
1653 			return -1;
1654 		}
1655 
1656 		if (prog_page(ns, num) == -1)
1657 			return -1;
1658 
1659 		page_no = ns->regs.row;
1660 
1661 		NS_DBG("do_state_action: copy %d bytes from int buf to (%#x, %#x), raw off = %d\n",
1662 			num, ns->regs.row, ns->regs.column, NS_RAW_OFFSET(ns) + ns->regs.off);
1663 		NS_LOG("programm page %d\n", ns->regs.row);
1664 
1665 		NS_UDELAY(programm_delay);
1666 		NS_UDELAY(output_cycle * ns->geom.pgsz / 1000 / busdiv);
1667 
1668 		if (write_error(page_no)) {
1669 			NS_WARN("simulating write failure in page %u\n", page_no);
1670 			return -1;
1671 		}
1672 
1673 		break;
1674 
1675 	case ACTION_ZEROOFF:
1676 		NS_DBG("do_state_action: set internal offset to 0\n");
1677 		ns->regs.off = 0;
1678 		break;
1679 
1680 	case ACTION_HALFOFF:
1681 		if (!(ns->options & OPT_PAGE512_8BIT)) {
1682 			NS_ERR("do_state_action: BUG! can't skip half of page for non-512"
1683 				"byte page size 8x chips\n");
1684 			return -1;
1685 		}
1686 		NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz/2);
1687 		ns->regs.off = ns->geom.pgsz/2;
1688 		break;
1689 
1690 	case ACTION_OOBOFF:
1691 		NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz);
1692 		ns->regs.off = ns->geom.pgsz;
1693 		break;
1694 
1695 	default:
1696 		NS_DBG("do_state_action: BUG! unknown action\n");
1697 	}
1698 
1699 	return 0;
1700 }
1701 
1702 /*
1703  * Switch simulator's state.
1704  */
1705 static void switch_state(struct nandsim *ns)
1706 {
1707 	if (ns->op) {
1708 		/*
1709 		 * The current operation have already been identified.
1710 		 * Just follow the states chain.
1711 		 */
1712 
1713 		ns->stateidx += 1;
1714 		ns->state = ns->nxstate;
1715 		ns->nxstate = ns->op[ns->stateidx + 1];
1716 
1717 		NS_DBG("switch_state: operation is known, switch to the next state, "
1718 			"state: %s, nxstate: %s\n",
1719 			get_state_name(ns->state), get_state_name(ns->nxstate));
1720 
1721 		/* See, whether we need to do some action */
1722 		if ((ns->state & ACTION_MASK) && do_state_action(ns, ns->state) < 0) {
1723 			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1724 			return;
1725 		}
1726 
1727 	} else {
1728 		/*
1729 		 * We don't yet know which operation we perform.
1730 		 * Try to identify it.
1731 		 */
1732 
1733 		/*
1734 		 *  The only event causing the switch_state function to
1735 		 *  be called with yet unknown operation is new command.
1736 		 */
1737 		ns->state = get_state_by_command(ns->regs.command);
1738 
1739 		NS_DBG("switch_state: operation is unknown, try to find it\n");
1740 
1741 		if (find_operation(ns, 0) != 0)
1742 			return;
1743 
1744 		if ((ns->state & ACTION_MASK) && do_state_action(ns, ns->state) < 0) {
1745 			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1746 			return;
1747 		}
1748 	}
1749 
1750 	/* For 16x devices column means the page offset in words */
1751 	if ((ns->nxstate & STATE_ADDR_MASK) && ns->busw == 16) {
1752 		NS_DBG("switch_state: double the column number for 16x device\n");
1753 		ns->regs.column <<= 1;
1754 	}
1755 
1756 	if (NS_STATE(ns->nxstate) == STATE_READY) {
1757 		/*
1758 		 * The current state is the last. Return to STATE_READY
1759 		 */
1760 
1761 		u_char status = NS_STATUS_OK(ns);
1762 
1763 		/* In case of data states, see if all bytes were input/output */
1764 		if ((ns->state & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK))
1765 			&& ns->regs.count != ns->regs.num) {
1766 			NS_WARN("switch_state: not all bytes were processed, %d left\n",
1767 					ns->regs.num - ns->regs.count);
1768 			status = NS_STATUS_FAILED(ns);
1769 		}
1770 
1771 		NS_DBG("switch_state: operation complete, switch to STATE_READY state\n");
1772 
1773 		switch_to_ready_state(ns, status);
1774 
1775 		return;
1776 	} else if (ns->nxstate & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK)) {
1777 		/*
1778 		 * If the next state is data input/output, switch to it now
1779 		 */
1780 
1781 		ns->state      = ns->nxstate;
1782 		ns->nxstate    = ns->op[++ns->stateidx + 1];
1783 		ns->regs.num   = ns->regs.count = 0;
1784 
1785 		NS_DBG("switch_state: the next state is data I/O, switch, "
1786 			"state: %s, nxstate: %s\n",
1787 			get_state_name(ns->state), get_state_name(ns->nxstate));
1788 
1789 		/*
1790 		 * Set the internal register to the count of bytes which
1791 		 * are expected to be input or output
1792 		 */
1793 		switch (NS_STATE(ns->state)) {
1794 			case STATE_DATAIN:
1795 			case STATE_DATAOUT:
1796 				ns->regs.num = ns->geom.pgszoob - ns->regs.off - ns->regs.column;
1797 				break;
1798 
1799 			case STATE_DATAOUT_ID:
1800 				ns->regs.num = ns->geom.idbytes;
1801 				break;
1802 
1803 			case STATE_DATAOUT_STATUS:
1804 				ns->regs.count = ns->regs.num = 0;
1805 				break;
1806 
1807 			default:
1808 				NS_ERR("switch_state: BUG! unknown data state\n");
1809 		}
1810 
1811 	} else if (ns->nxstate & STATE_ADDR_MASK) {
1812 		/*
1813 		 * If the next state is address input, set the internal
1814 		 * register to the number of expected address bytes
1815 		 */
1816 
1817 		ns->regs.count = 0;
1818 
1819 		switch (NS_STATE(ns->nxstate)) {
1820 			case STATE_ADDR_PAGE:
1821 				ns->regs.num = ns->geom.pgaddrbytes;
1822 
1823 				break;
1824 			case STATE_ADDR_SEC:
1825 				ns->regs.num = ns->geom.secaddrbytes;
1826 				break;
1827 
1828 			case STATE_ADDR_ZERO:
1829 				ns->regs.num = 1;
1830 				break;
1831 
1832 			case STATE_ADDR_COLUMN:
1833 				/* Column address is always 2 bytes */
1834 				ns->regs.num = ns->geom.pgaddrbytes - ns->geom.secaddrbytes;
1835 				break;
1836 
1837 			default:
1838 				NS_ERR("switch_state: BUG! unknown address state\n");
1839 		}
1840 	} else {
1841 		/*
1842 		 * Just reset internal counters.
1843 		 */
1844 
1845 		ns->regs.num = 0;
1846 		ns->regs.count = 0;
1847 	}
1848 }
1849 
1850 static u_char ns_nand_read_byte(struct nand_chip *chip)
1851 {
1852 	struct nandsim *ns = nand_get_controller_data(chip);
1853 	u_char outb = 0x00;
1854 
1855 	/* Sanity and correctness checks */
1856 	if (!ns->lines.ce) {
1857 		NS_ERR("read_byte: chip is disabled, return %#x\n", (uint)outb);
1858 		return outb;
1859 	}
1860 	if (ns->lines.ale || ns->lines.cle) {
1861 		NS_ERR("read_byte: ALE or CLE pin is high, return %#x\n", (uint)outb);
1862 		return outb;
1863 	}
1864 	if (!(ns->state & STATE_DATAOUT_MASK)) {
1865 		NS_WARN("read_byte: unexpected data output cycle, state is %s "
1866 			"return %#x\n", get_state_name(ns->state), (uint)outb);
1867 		return outb;
1868 	}
1869 
1870 	/* Status register may be read as many times as it is wanted */
1871 	if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS) {
1872 		NS_DBG("read_byte: return %#x status\n", ns->regs.status);
1873 		return ns->regs.status;
1874 	}
1875 
1876 	/* Check if there is any data in the internal buffer which may be read */
1877 	if (ns->regs.count == ns->regs.num) {
1878 		NS_WARN("read_byte: no more data to output, return %#x\n", (uint)outb);
1879 		return outb;
1880 	}
1881 
1882 	switch (NS_STATE(ns->state)) {
1883 		case STATE_DATAOUT:
1884 			if (ns->busw == 8) {
1885 				outb = ns->buf.byte[ns->regs.count];
1886 				ns->regs.count += 1;
1887 			} else {
1888 				outb = (u_char)cpu_to_le16(ns->buf.word[ns->regs.count >> 1]);
1889 				ns->regs.count += 2;
1890 			}
1891 			break;
1892 		case STATE_DATAOUT_ID:
1893 			NS_DBG("read_byte: read ID byte %d, total = %d\n", ns->regs.count, ns->regs.num);
1894 			outb = ns->ids[ns->regs.count];
1895 			ns->regs.count += 1;
1896 			break;
1897 		default:
1898 			BUG();
1899 	}
1900 
1901 	if (ns->regs.count == ns->regs.num) {
1902 		NS_DBG("read_byte: all bytes were read\n");
1903 
1904 		if (NS_STATE(ns->nxstate) == STATE_READY)
1905 			switch_state(ns);
1906 	}
1907 
1908 	return outb;
1909 }
1910 
1911 static void ns_nand_write_byte(struct nand_chip *chip, u_char byte)
1912 {
1913 	struct nandsim *ns = nand_get_controller_data(chip);
1914 
1915 	/* Sanity and correctness checks */
1916 	if (!ns->lines.ce) {
1917 		NS_ERR("write_byte: chip is disabled, ignore write\n");
1918 		return;
1919 	}
1920 	if (ns->lines.ale && ns->lines.cle) {
1921 		NS_ERR("write_byte: ALE and CLE pins are high simultaneously, ignore write\n");
1922 		return;
1923 	}
1924 
1925 	if (ns->lines.cle == 1) {
1926 		/*
1927 		 * The byte written is a command.
1928 		 */
1929 
1930 		if (byte == NAND_CMD_RESET) {
1931 			NS_LOG("reset chip\n");
1932 			switch_to_ready_state(ns, NS_STATUS_OK(ns));
1933 			return;
1934 		}
1935 
1936 		/* Check that the command byte is correct */
1937 		if (check_command(byte)) {
1938 			NS_ERR("write_byte: unknown command %#x\n", (uint)byte);
1939 			return;
1940 		}
1941 
1942 		if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS
1943 			|| NS_STATE(ns->state) == STATE_DATAOUT) {
1944 			int row = ns->regs.row;
1945 
1946 			switch_state(ns);
1947 			if (byte == NAND_CMD_RNDOUT)
1948 				ns->regs.row = row;
1949 		}
1950 
1951 		/* Check if chip is expecting command */
1952 		if (NS_STATE(ns->nxstate) != STATE_UNKNOWN && !(ns->nxstate & STATE_CMD_MASK)) {
1953 			/* Do not warn if only 2 id bytes are read */
1954 			if (!(ns->regs.command == NAND_CMD_READID &&
1955 			    NS_STATE(ns->state) == STATE_DATAOUT_ID && ns->regs.count == 2)) {
1956 				/*
1957 				 * We are in situation when something else (not command)
1958 				 * was expected but command was input. In this case ignore
1959 				 * previous command(s)/state(s) and accept the last one.
1960 				 */
1961 				NS_WARN("write_byte: command (%#x) wasn't expected, expected state is %s, "
1962 					"ignore previous states\n", (uint)byte, get_state_name(ns->nxstate));
1963 			}
1964 			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1965 		}
1966 
1967 		NS_DBG("command byte corresponding to %s state accepted\n",
1968 			get_state_name(get_state_by_command(byte)));
1969 		ns->regs.command = byte;
1970 		switch_state(ns);
1971 
1972 	} else if (ns->lines.ale == 1) {
1973 		/*
1974 		 * The byte written is an address.
1975 		 */
1976 
1977 		if (NS_STATE(ns->nxstate) == STATE_UNKNOWN) {
1978 
1979 			NS_DBG("write_byte: operation isn't known yet, identify it\n");
1980 
1981 			if (find_operation(ns, 1) < 0)
1982 				return;
1983 
1984 			if ((ns->state & ACTION_MASK) && do_state_action(ns, ns->state) < 0) {
1985 				switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1986 				return;
1987 			}
1988 
1989 			ns->regs.count = 0;
1990 			switch (NS_STATE(ns->nxstate)) {
1991 				case STATE_ADDR_PAGE:
1992 					ns->regs.num = ns->geom.pgaddrbytes;
1993 					break;
1994 				case STATE_ADDR_SEC:
1995 					ns->regs.num = ns->geom.secaddrbytes;
1996 					break;
1997 				case STATE_ADDR_ZERO:
1998 					ns->regs.num = 1;
1999 					break;
2000 				default:
2001 					BUG();
2002 			}
2003 		}
2004 
2005 		/* Check that chip is expecting address */
2006 		if (!(ns->nxstate & STATE_ADDR_MASK)) {
2007 			NS_ERR("write_byte: address (%#x) isn't expected, expected state is %s, "
2008 				"switch to STATE_READY\n", (uint)byte, get_state_name(ns->nxstate));
2009 			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2010 			return;
2011 		}
2012 
2013 		/* Check if this is expected byte */
2014 		if (ns->regs.count == ns->regs.num) {
2015 			NS_ERR("write_byte: no more address bytes expected\n");
2016 			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2017 			return;
2018 		}
2019 
2020 		accept_addr_byte(ns, byte);
2021 
2022 		ns->regs.count += 1;
2023 
2024 		NS_DBG("write_byte: address byte %#x was accepted (%d bytes input, %d expected)\n",
2025 				(uint)byte, ns->regs.count, ns->regs.num);
2026 
2027 		if (ns->regs.count == ns->regs.num) {
2028 			NS_DBG("address (%#x, %#x) is accepted\n", ns->regs.row, ns->regs.column);
2029 			switch_state(ns);
2030 		}
2031 
2032 	} else {
2033 		/*
2034 		 * The byte written is an input data.
2035 		 */
2036 
2037 		/* Check that chip is expecting data input */
2038 		if (!(ns->state & STATE_DATAIN_MASK)) {
2039 			NS_ERR("write_byte: data input (%#x) isn't expected, state is %s, "
2040 				"switch to %s\n", (uint)byte,
2041 				get_state_name(ns->state), get_state_name(STATE_READY));
2042 			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2043 			return;
2044 		}
2045 
2046 		/* Check if this is expected byte */
2047 		if (ns->regs.count == ns->regs.num) {
2048 			NS_WARN("write_byte: %u input bytes has already been accepted, ignore write\n",
2049 					ns->regs.num);
2050 			return;
2051 		}
2052 
2053 		if (ns->busw == 8) {
2054 			ns->buf.byte[ns->regs.count] = byte;
2055 			ns->regs.count += 1;
2056 		} else {
2057 			ns->buf.word[ns->regs.count >> 1] = cpu_to_le16((uint16_t)byte);
2058 			ns->regs.count += 2;
2059 		}
2060 	}
2061 
2062 	return;
2063 }
2064 
2065 static void ns_nand_write_buf(struct nand_chip *chip, const u_char *buf,
2066 			      int len)
2067 {
2068 	struct nandsim *ns = nand_get_controller_data(chip);
2069 
2070 	/* Check that chip is expecting data input */
2071 	if (!(ns->state & STATE_DATAIN_MASK)) {
2072 		NS_ERR("write_buf: data input isn't expected, state is %s, "
2073 			"switch to STATE_READY\n", get_state_name(ns->state));
2074 		switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2075 		return;
2076 	}
2077 
2078 	/* Check if these are expected bytes */
2079 	if (ns->regs.count + len > ns->regs.num) {
2080 		NS_ERR("write_buf: too many input bytes\n");
2081 		switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2082 		return;
2083 	}
2084 
2085 	memcpy(ns->buf.byte + ns->regs.count, buf, len);
2086 	ns->regs.count += len;
2087 
2088 	if (ns->regs.count == ns->regs.num) {
2089 		NS_DBG("write_buf: %d bytes were written\n", ns->regs.count);
2090 	}
2091 }
2092 
2093 static void ns_nand_read_buf(struct nand_chip *chip, u_char *buf, int len)
2094 {
2095 	struct nandsim *ns = nand_get_controller_data(chip);
2096 
2097 	/* Sanity and correctness checks */
2098 	if (!ns->lines.ce) {
2099 		NS_ERR("read_buf: chip is disabled\n");
2100 		return;
2101 	}
2102 	if (ns->lines.ale || ns->lines.cle) {
2103 		NS_ERR("read_buf: ALE or CLE pin is high\n");
2104 		return;
2105 	}
2106 	if (!(ns->state & STATE_DATAOUT_MASK)) {
2107 		NS_WARN("read_buf: unexpected data output cycle, current state is %s\n",
2108 			get_state_name(ns->state));
2109 		return;
2110 	}
2111 
2112 	if (NS_STATE(ns->state) != STATE_DATAOUT) {
2113 		int i;
2114 
2115 		for (i = 0; i < len; i++)
2116 			buf[i] = ns_nand_read_byte(chip);
2117 
2118 		return;
2119 	}
2120 
2121 	/* Check if these are expected bytes */
2122 	if (ns->regs.count + len > ns->regs.num) {
2123 		NS_ERR("read_buf: too many bytes to read\n");
2124 		switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2125 		return;
2126 	}
2127 
2128 	memcpy(buf, ns->buf.byte + ns->regs.count, len);
2129 	ns->regs.count += len;
2130 
2131 	if (ns->regs.count == ns->regs.num) {
2132 		if (NS_STATE(ns->nxstate) == STATE_READY)
2133 			switch_state(ns);
2134 	}
2135 
2136 	return;
2137 }
2138 
2139 static int ns_exec_op(struct nand_chip *chip, const struct nand_operation *op,
2140 		      bool check_only)
2141 {
2142 	int i;
2143 	unsigned int op_id;
2144 	const struct nand_op_instr *instr = NULL;
2145 	struct nandsim *ns = nand_get_controller_data(chip);
2146 
2147 	ns->lines.ce = 1;
2148 
2149 	for (op_id = 0; op_id < op->ninstrs; op_id++) {
2150 		instr = &op->instrs[op_id];
2151 		ns->lines.cle = 0;
2152 		ns->lines.ale = 0;
2153 
2154 		switch (instr->type) {
2155 		case NAND_OP_CMD_INSTR:
2156 			ns->lines.cle = 1;
2157 			ns_nand_write_byte(chip, instr->ctx.cmd.opcode);
2158 			break;
2159 		case NAND_OP_ADDR_INSTR:
2160 			ns->lines.ale = 1;
2161 			for (i = 0; i < instr->ctx.addr.naddrs; i++)
2162 				ns_nand_write_byte(chip, instr->ctx.addr.addrs[i]);
2163 			break;
2164 		case NAND_OP_DATA_IN_INSTR:
2165 			ns_nand_read_buf(chip, instr->ctx.data.buf.in, instr->ctx.data.len);
2166 			break;
2167 		case NAND_OP_DATA_OUT_INSTR:
2168 			ns_nand_write_buf(chip, instr->ctx.data.buf.out, instr->ctx.data.len);
2169 			break;
2170 		case NAND_OP_WAITRDY_INSTR:
2171 			/* we are always ready */
2172 			break;
2173 		}
2174 	}
2175 
2176 	return 0;
2177 }
2178 
2179 static int ns_attach_chip(struct nand_chip *chip)
2180 {
2181 	unsigned int eccsteps, eccbytes;
2182 
2183 	if (!bch)
2184 		return 0;
2185 
2186 	if (!mtd_nand_has_bch()) {
2187 		NS_ERR("BCH ECC support is disabled\n");
2188 		return -EINVAL;
2189 	}
2190 
2191 	/* Use 512-byte ecc blocks */
2192 	eccsteps = nsmtd->writesize / 512;
2193 	eccbytes = ((bch * 13) + 7) / 8;
2194 
2195 	/* Do not bother supporting small page devices */
2196 	if (nsmtd->oobsize < 64 || !eccsteps) {
2197 		NS_ERR("BCH not available on small page devices\n");
2198 		return -EINVAL;
2199 	}
2200 
2201 	if (((eccbytes * eccsteps) + 2) > nsmtd->oobsize) {
2202 		NS_ERR("Invalid BCH value %u\n", bch);
2203 		return -EINVAL;
2204 	}
2205 
2206 	chip->ecc.mode = NAND_ECC_SOFT;
2207 	chip->ecc.algo = NAND_ECC_BCH;
2208 	chip->ecc.size = 512;
2209 	chip->ecc.strength = bch;
2210 	chip->ecc.bytes = eccbytes;
2211 
2212 	NS_INFO("Using %u-bit/%u bytes BCH ECC\n", bch, chip->ecc.size);
2213 
2214 	return 0;
2215 }
2216 
2217 static const struct nand_controller_ops ns_controller_ops = {
2218 	.attach_chip = ns_attach_chip,
2219 	.exec_op = ns_exec_op,
2220 };
2221 
2222 /*
2223  * Module initialization function
2224  */
2225 static int __init ns_init_module(void)
2226 {
2227 	struct nand_chip *chip;
2228 	struct nandsim *ns;
2229 	int retval = -ENOMEM, i;
2230 
2231 	if (bus_width != 8 && bus_width != 16) {
2232 		NS_ERR("wrong bus width (%d), use only 8 or 16\n", bus_width);
2233 		return -EINVAL;
2234 	}
2235 
2236 	ns = kzalloc(sizeof(struct nandsim), GFP_KERNEL);
2237 	if (!ns) {
2238 		NS_ERR("unable to allocate core structures.\n");
2239 		return -ENOMEM;
2240 	}
2241 	chip	    = &ns->chip;
2242 	nsmtd       = nand_to_mtd(chip);
2243 	nand_set_controller_data(chip, (void *)ns);
2244 
2245 	chip->ecc.mode   = NAND_ECC_SOFT;
2246 	chip->ecc.algo   = NAND_ECC_HAMMING;
2247 	/* The NAND_SKIP_BBTSCAN option is necessary for 'overridesize' */
2248 	/* and 'badblocks' parameters to work */
2249 	chip->options   |= NAND_SKIP_BBTSCAN;
2250 
2251 	switch (bbt) {
2252 	case 2:
2253 		chip->bbt_options |= NAND_BBT_NO_OOB;
2254 		/* fall through */
2255 	case 1:
2256 		chip->bbt_options |= NAND_BBT_USE_FLASH;
2257 		/* fall through */
2258 	case 0:
2259 		break;
2260 	default:
2261 		NS_ERR("bbt has to be 0..2\n");
2262 		retval = -EINVAL;
2263 		goto error;
2264 	}
2265 	/*
2266 	 * Perform minimum nandsim structure initialization to handle
2267 	 * the initial ID read command correctly
2268 	 */
2269 	if (id_bytes[6] != 0xFF || id_bytes[7] != 0xFF)
2270 		ns->geom.idbytes = 8;
2271 	else if (id_bytes[4] != 0xFF || id_bytes[5] != 0xFF)
2272 		ns->geom.idbytes = 6;
2273 	else if (id_bytes[2] != 0xFF || id_bytes[3] != 0xFF)
2274 		ns->geom.idbytes = 4;
2275 	else
2276 		ns->geom.idbytes = 2;
2277 	ns->regs.status = NS_STATUS_OK(ns);
2278 	ns->nxstate = STATE_UNKNOWN;
2279 	ns->options |= OPT_PAGE512; /* temporary value */
2280 	memcpy(ns->ids, id_bytes, sizeof(ns->ids));
2281 	if (bus_width == 16) {
2282 		ns->busw = 16;
2283 		chip->options |= NAND_BUSWIDTH_16;
2284 	}
2285 
2286 	nsmtd->owner = THIS_MODULE;
2287 
2288 	if ((retval = parse_weakblocks()) != 0)
2289 		goto error;
2290 
2291 	if ((retval = parse_weakpages()) != 0)
2292 		goto error;
2293 
2294 	if ((retval = parse_gravepages()) != 0)
2295 		goto error;
2296 
2297 	nand_controller_init(&ns->base);
2298 	ns->base.ops = &ns_controller_ops;
2299 	chip->controller = &ns->base;
2300 
2301 	retval = nand_scan(chip, 1);
2302 	if (retval) {
2303 		NS_ERR("Could not scan NAND Simulator device\n");
2304 		goto error;
2305 	}
2306 
2307 	if (overridesize) {
2308 		uint64_t new_size = (uint64_t)nsmtd->erasesize << overridesize;
2309 		struct nand_memory_organization *memorg;
2310 		u64 targetsize;
2311 
2312 		memorg = nanddev_get_memorg(&chip->base);
2313 
2314 		if (new_size >> overridesize != nsmtd->erasesize) {
2315 			NS_ERR("overridesize is too big\n");
2316 			retval = -EINVAL;
2317 			goto err_exit;
2318 		}
2319 
2320 		/* N.B. This relies on nand_scan not doing anything with the size before we change it */
2321 		nsmtd->size = new_size;
2322 		memorg->eraseblocks_per_lun = 1 << overridesize;
2323 		targetsize = nanddev_target_size(&chip->base);
2324 		chip->chip_shift = ffs(nsmtd->erasesize) + overridesize - 1;
2325 		chip->pagemask = (targetsize >> chip->page_shift) - 1;
2326 	}
2327 
2328 	if ((retval = setup_wear_reporting(nsmtd)) != 0)
2329 		goto err_exit;
2330 
2331 	if ((retval = init_nandsim(nsmtd)) != 0)
2332 		goto err_exit;
2333 
2334 	if ((retval = nand_create_bbt(chip)) != 0)
2335 		goto err_exit;
2336 
2337 	if ((retval = parse_badblocks(ns, nsmtd)) != 0)
2338 		goto err_exit;
2339 
2340 	/* Register NAND partitions */
2341 	retval = mtd_device_register(nsmtd, &ns->partitions[0],
2342 				     ns->nbparts);
2343 	if (retval != 0)
2344 		goto err_exit;
2345 
2346 	if ((retval = nandsim_debugfs_create(ns)) != 0)
2347 		goto err_exit;
2348 
2349         return 0;
2350 
2351 err_exit:
2352 	free_nandsim(ns);
2353 	nand_release(chip);
2354 	for (i = 0;i < ARRAY_SIZE(ns->partitions); ++i)
2355 		kfree(ns->partitions[i].name);
2356 error:
2357 	kfree(ns);
2358 	free_lists();
2359 
2360 	return retval;
2361 }
2362 
2363 module_init(ns_init_module);
2364 
2365 /*
2366  * Module clean-up function
2367  */
2368 static void __exit ns_cleanup_module(void)
2369 {
2370 	struct nand_chip *chip = mtd_to_nand(nsmtd);
2371 	struct nandsim *ns = nand_get_controller_data(chip);
2372 	int i;
2373 
2374 	free_nandsim(ns);    /* Free nandsim private resources */
2375 	nand_release(chip); /* Unregister driver */
2376 	for (i = 0;i < ARRAY_SIZE(ns->partitions); ++i)
2377 		kfree(ns->partitions[i].name);
2378 	kfree(ns);        /* Free other structures */
2379 	free_lists();
2380 }
2381 
2382 module_exit(ns_cleanup_module);
2383 
2384 MODULE_LICENSE ("GPL");
2385 MODULE_AUTHOR ("Artem B. Bityuckiy");
2386 MODULE_DESCRIPTION ("The NAND flash simulator");
2387