1/*
2 * NAND flash simulator.
3 *
4 * Author: Artem B. Bityuckiy <dedekind@oktetlabs.ru>, <dedekind@infradead.org>
5 *
6 * Copyright (C) 2004 Nokia Corporation
7 *
8 * Note: NS means "NAND Simulator".
9 * Note: Input means input TO flash chip, output means output FROM chip.
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the
13 * Free Software Foundation; either version 2, or (at your option) any later
14 * version.
15 *
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
19 * Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
24 */
25
26#include <linux/init.h>
27#include <linux/types.h>
28#include <linux/module.h>
29#include <linux/moduleparam.h>
30#include <linux/vmalloc.h>
31#include <linux/math64.h>
32#include <linux/slab.h>
33#include <linux/errno.h>
34#include <linux/string.h>
35#include <linux/mtd/mtd.h>
36#include <linux/mtd/nand.h>
37#include <linux/mtd/nand_bch.h>
38#include <linux/mtd/partitions.h>
39#include <linux/delay.h>
40#include <linux/list.h>
41#include <linux/random.h>
42#include <linux/sched.h>
43#include <linux/fs.h>
44#include <linux/pagemap.h>
45#include <linux/seq_file.h>
46#include <linux/debugfs.h>
47
48/* Default simulator parameters values */
49#if !defined(CONFIG_NANDSIM_FIRST_ID_BYTE)  || \
50    !defined(CONFIG_NANDSIM_SECOND_ID_BYTE) || \
51    !defined(CONFIG_NANDSIM_THIRD_ID_BYTE)  || \
52    !defined(CONFIG_NANDSIM_FOURTH_ID_BYTE)
53#define CONFIG_NANDSIM_FIRST_ID_BYTE  0x98
54#define CONFIG_NANDSIM_SECOND_ID_BYTE 0x39
55#define CONFIG_NANDSIM_THIRD_ID_BYTE  0xFF /* No byte */
56#define CONFIG_NANDSIM_FOURTH_ID_BYTE 0xFF /* No byte */
57#endif
58
59#ifndef CONFIG_NANDSIM_ACCESS_DELAY
60#define CONFIG_NANDSIM_ACCESS_DELAY 25
61#endif
62#ifndef CONFIG_NANDSIM_PROGRAMM_DELAY
63#define CONFIG_NANDSIM_PROGRAMM_DELAY 200
64#endif
65#ifndef CONFIG_NANDSIM_ERASE_DELAY
66#define CONFIG_NANDSIM_ERASE_DELAY 2
67#endif
68#ifndef CONFIG_NANDSIM_OUTPUT_CYCLE
69#define CONFIG_NANDSIM_OUTPUT_CYCLE 40
70#endif
71#ifndef CONFIG_NANDSIM_INPUT_CYCLE
72#define CONFIG_NANDSIM_INPUT_CYCLE  50
73#endif
74#ifndef CONFIG_NANDSIM_BUS_WIDTH
75#define CONFIG_NANDSIM_BUS_WIDTH  8
76#endif
77#ifndef CONFIG_NANDSIM_DO_DELAYS
78#define CONFIG_NANDSIM_DO_DELAYS  0
79#endif
80#ifndef CONFIG_NANDSIM_LOG
81#define CONFIG_NANDSIM_LOG        0
82#endif
83#ifndef CONFIG_NANDSIM_DBG
84#define CONFIG_NANDSIM_DBG        0
85#endif
86#ifndef CONFIG_NANDSIM_MAX_PARTS
87#define CONFIG_NANDSIM_MAX_PARTS  32
88#endif
89
90static uint access_delay   = CONFIG_NANDSIM_ACCESS_DELAY;
91static uint programm_delay = CONFIG_NANDSIM_PROGRAMM_DELAY;
92static uint erase_delay    = CONFIG_NANDSIM_ERASE_DELAY;
93static uint output_cycle   = CONFIG_NANDSIM_OUTPUT_CYCLE;
94static uint input_cycle    = CONFIG_NANDSIM_INPUT_CYCLE;
95static uint bus_width      = CONFIG_NANDSIM_BUS_WIDTH;
96static uint do_delays      = CONFIG_NANDSIM_DO_DELAYS;
97static uint log            = CONFIG_NANDSIM_LOG;
98static uint dbg            = CONFIG_NANDSIM_DBG;
99static unsigned long parts[CONFIG_NANDSIM_MAX_PARTS];
100static unsigned int parts_num;
101static char *badblocks = NULL;
102static char *weakblocks = NULL;
103static char *weakpages = NULL;
104static unsigned int bitflips = 0;
105static char *gravepages = NULL;
106static unsigned int overridesize = 0;
107static char *cache_file = NULL;
108static unsigned int bbt;
109static unsigned int bch;
110static u_char id_bytes[8] = {
111	[0] = CONFIG_NANDSIM_FIRST_ID_BYTE,
112	[1] = CONFIG_NANDSIM_SECOND_ID_BYTE,
113	[2] = CONFIG_NANDSIM_THIRD_ID_BYTE,
114	[3] = CONFIG_NANDSIM_FOURTH_ID_BYTE,
115	[4 ... 7] = 0xFF,
116};
117
118module_param_array(id_bytes, byte, NULL, 0400);
119module_param_named(first_id_byte, id_bytes[0], byte, 0400);
120module_param_named(second_id_byte, id_bytes[1], byte, 0400);
121module_param_named(third_id_byte, id_bytes[2], byte, 0400);
122module_param_named(fourth_id_byte, id_bytes[3], byte, 0400);
123module_param(access_delay,   uint, 0400);
124module_param(programm_delay, uint, 0400);
125module_param(erase_delay,    uint, 0400);
126module_param(output_cycle,   uint, 0400);
127module_param(input_cycle,    uint, 0400);
128module_param(bus_width,      uint, 0400);
129module_param(do_delays,      uint, 0400);
130module_param(log,            uint, 0400);
131module_param(dbg,            uint, 0400);
132module_param_array(parts, ulong, &parts_num, 0400);
133module_param(badblocks,      charp, 0400);
134module_param(weakblocks,     charp, 0400);
135module_param(weakpages,      charp, 0400);
136module_param(bitflips,       uint, 0400);
137module_param(gravepages,     charp, 0400);
138module_param(overridesize,   uint, 0400);
139module_param(cache_file,     charp, 0400);
140module_param(bbt,	     uint, 0400);
141module_param(bch,	     uint, 0400);
142
143MODULE_PARM_DESC(id_bytes,       "The ID bytes returned by NAND Flash 'read ID' command");
144MODULE_PARM_DESC(first_id_byte,  "The first byte returned by NAND Flash 'read ID' command (manufacturer ID) (obsolete)");
145MODULE_PARM_DESC(second_id_byte, "The second byte returned by NAND Flash 'read ID' command (chip ID) (obsolete)");
146MODULE_PARM_DESC(third_id_byte,  "The third byte returned by NAND Flash 'read ID' command (obsolete)");
147MODULE_PARM_DESC(fourth_id_byte, "The fourth byte returned by NAND Flash 'read ID' command (obsolete)");
148MODULE_PARM_DESC(access_delay,   "Initial page access delay (microseconds)");
149MODULE_PARM_DESC(programm_delay, "Page programm delay (microseconds");
150MODULE_PARM_DESC(erase_delay,    "Sector erase delay (milliseconds)");
151MODULE_PARM_DESC(output_cycle,   "Word output (from flash) time (nanoseconds)");
152MODULE_PARM_DESC(input_cycle,    "Word input (to flash) time (nanoseconds)");
153MODULE_PARM_DESC(bus_width,      "Chip's bus width (8- or 16-bit)");
154MODULE_PARM_DESC(do_delays,      "Simulate NAND delays using busy-waits if not zero");
155MODULE_PARM_DESC(log,            "Perform logging if not zero");
156MODULE_PARM_DESC(dbg,            "Output debug information if not zero");
157MODULE_PARM_DESC(parts,          "Partition sizes (in erase blocks) separated by commas");
158/* Page and erase block positions for the following parameters are independent of any partitions */
159MODULE_PARM_DESC(badblocks,      "Erase blocks that are initially marked bad, separated by commas");
160MODULE_PARM_DESC(weakblocks,     "Weak erase blocks [: remaining erase cycles (defaults to 3)]"
161				 " separated by commas e.g. 113:2 means eb 113"
162				 " can be erased only twice before failing");
163MODULE_PARM_DESC(weakpages,      "Weak pages [: maximum writes (defaults to 3)]"
164				 " separated by commas e.g. 1401:2 means page 1401"
165				 " can be written only twice before failing");
166MODULE_PARM_DESC(bitflips,       "Maximum number of random bit flips per page (zero by default)");
167MODULE_PARM_DESC(gravepages,     "Pages that lose data [: maximum reads (defaults to 3)]"
168				 " separated by commas e.g. 1401:2 means page 1401"
169				 " can be read only twice before failing");
170MODULE_PARM_DESC(overridesize,   "Specifies the NAND Flash size overriding the ID bytes. "
171				 "The size is specified in erase blocks and as the exponent of a power of two"
172				 " e.g. 5 means a size of 32 erase blocks");
173MODULE_PARM_DESC(cache_file,     "File to use to cache nand pages instead of memory");
174MODULE_PARM_DESC(bbt,		 "0 OOB, 1 BBT with marker in OOB, 2 BBT with marker in data area");
175MODULE_PARM_DESC(bch,		 "Enable BCH ecc and set how many bits should "
176				 "be correctable in 512-byte blocks");
177
178/* The largest possible page size */
179#define NS_LARGEST_PAGE_SIZE	4096
180
181/* The prefix for simulator output */
182#define NS_OUTPUT_PREFIX "[nandsim]"
183
184/* Simulator's output macros (logging, debugging, warning, error) */
185#define NS_LOG(args...) \
186	do { if (log) printk(KERN_DEBUG NS_OUTPUT_PREFIX " log: " args); } while(0)
187#define NS_DBG(args...) \
188	do { if (dbg) printk(KERN_DEBUG NS_OUTPUT_PREFIX " debug: " args); } while(0)
189#define NS_WARN(args...) \
190	do { printk(KERN_WARNING NS_OUTPUT_PREFIX " warning: " args); } while(0)
191#define NS_ERR(args...) \
192	do { printk(KERN_ERR NS_OUTPUT_PREFIX " error: " args); } while(0)
193#define NS_INFO(args...) \
194	do { printk(KERN_INFO NS_OUTPUT_PREFIX " " args); } while(0)
195
196/* Busy-wait delay macros (microseconds, milliseconds) */
197#define NS_UDELAY(us) \
198        do { if (do_delays) udelay(us); } while(0)
199#define NS_MDELAY(us) \
200        do { if (do_delays) mdelay(us); } while(0)
201
202/* Is the nandsim structure initialized ? */
203#define NS_IS_INITIALIZED(ns) ((ns)->geom.totsz != 0)
204
205/* Good operation completion status */
206#define NS_STATUS_OK(ns) (NAND_STATUS_READY | (NAND_STATUS_WP * ((ns)->lines.wp == 0)))
207
208/* Operation failed completion status */
209#define NS_STATUS_FAILED(ns) (NAND_STATUS_FAIL | NS_STATUS_OK(ns))
210
211/* Calculate the page offset in flash RAM image by (row, column) address */
212#define NS_RAW_OFFSET(ns) \
213	(((ns)->regs.row * (ns)->geom.pgszoob) + (ns)->regs.column)
214
215/* Calculate the OOB offset in flash RAM image by (row, column) address */
216#define NS_RAW_OFFSET_OOB(ns) (NS_RAW_OFFSET(ns) + ns->geom.pgsz)
217
218/* After a command is input, the simulator goes to one of the following states */
219#define STATE_CMD_READ0        0x00000001 /* read data from the beginning of page */
220#define STATE_CMD_READ1        0x00000002 /* read data from the second half of page */
221#define STATE_CMD_READSTART    0x00000003 /* read data second command (large page devices) */
222#define STATE_CMD_PAGEPROG     0x00000004 /* start page program */
223#define STATE_CMD_READOOB      0x00000005 /* read OOB area */
224#define STATE_CMD_ERASE1       0x00000006 /* sector erase first command */
225#define STATE_CMD_STATUS       0x00000007 /* read status */
226#define STATE_CMD_SEQIN        0x00000009 /* sequential data input */
227#define STATE_CMD_READID       0x0000000A /* read ID */
228#define STATE_CMD_ERASE2       0x0000000B /* sector erase second command */
229#define STATE_CMD_RESET        0x0000000C /* reset */
230#define STATE_CMD_RNDOUT       0x0000000D /* random output command */
231#define STATE_CMD_RNDOUTSTART  0x0000000E /* random output start command */
232#define STATE_CMD_MASK         0x0000000F /* command states mask */
233
234/* After an address is input, the simulator goes to one of these states */
235#define STATE_ADDR_PAGE        0x00000010 /* full (row, column) address is accepted */
236#define STATE_ADDR_SEC         0x00000020 /* sector address was accepted */
237#define STATE_ADDR_COLUMN      0x00000030 /* column address was accepted */
238#define STATE_ADDR_ZERO        0x00000040 /* one byte zero address was accepted */
239#define STATE_ADDR_MASK        0x00000070 /* address states mask */
240
241/* During data input/output the simulator is in these states */
242#define STATE_DATAIN           0x00000100 /* waiting for data input */
243#define STATE_DATAIN_MASK      0x00000100 /* data input states mask */
244
245#define STATE_DATAOUT          0x00001000 /* waiting for page data output */
246#define STATE_DATAOUT_ID       0x00002000 /* waiting for ID bytes output */
247#define STATE_DATAOUT_STATUS   0x00003000 /* waiting for status output */
248#define STATE_DATAOUT_MASK     0x00007000 /* data output states mask */
249
250/* Previous operation is done, ready to accept new requests */
251#define STATE_READY            0x00000000
252
253/* This state is used to mark that the next state isn't known yet */
254#define STATE_UNKNOWN          0x10000000
255
256/* Simulator's actions bit masks */
257#define ACTION_CPY       0x00100000 /* copy page/OOB to the internal buffer */
258#define ACTION_PRGPAGE   0x00200000 /* program the internal buffer to flash */
259#define ACTION_SECERASE  0x00300000 /* erase sector */
260#define ACTION_ZEROOFF   0x00400000 /* don't add any offset to address */
261#define ACTION_HALFOFF   0x00500000 /* add to address half of page */
262#define ACTION_OOBOFF    0x00600000 /* add to address OOB offset */
263#define ACTION_MASK      0x00700000 /* action mask */
264
265#define NS_OPER_NUM      13 /* Number of operations supported by the simulator */
266#define NS_OPER_STATES   6  /* Maximum number of states in operation */
267
268#define OPT_ANY          0xFFFFFFFF /* any chip supports this operation */
269#define OPT_PAGE512      0x00000002 /* 512-byte  page chips */
270#define OPT_PAGE2048     0x00000008 /* 2048-byte page chips */
271#define OPT_PAGE512_8BIT 0x00000040 /* 512-byte page chips with 8-bit bus width */
272#define OPT_PAGE4096     0x00000080 /* 4096-byte page chips */
273#define OPT_LARGEPAGE    (OPT_PAGE2048 | OPT_PAGE4096) /* 2048 & 4096-byte page chips */
274#define OPT_SMALLPAGE    (OPT_PAGE512) /* 512-byte page chips */
275
276/* Remove action bits from state */
277#define NS_STATE(x) ((x) & ~ACTION_MASK)
278
279/*
280 * Maximum previous states which need to be saved. Currently saving is
281 * only needed for page program operation with preceded read command
282 * (which is only valid for 512-byte pages).
283 */
284#define NS_MAX_PREVSTATES 1
285
286/* Maximum page cache pages needed to read or write a NAND page to the cache_file */
287#define NS_MAX_HELD_PAGES 16
288
289struct nandsim_debug_info {
290	struct dentry *dfs_root;
291	struct dentry *dfs_wear_report;
292};
293
294/*
295 * A union to represent flash memory contents and flash buffer.
296 */
297union ns_mem {
298	u_char *byte;    /* for byte access */
299	uint16_t *word;  /* for 16-bit word access */
300};
301
302/*
303 * The structure which describes all the internal simulator data.
304 */
305struct nandsim {
306	struct mtd_partition partitions[CONFIG_NANDSIM_MAX_PARTS];
307	unsigned int nbparts;
308
309	uint busw;              /* flash chip bus width (8 or 16) */
310	u_char ids[8];          /* chip's ID bytes */
311	uint32_t options;       /* chip's characteristic bits */
312	uint32_t state;         /* current chip state */
313	uint32_t nxstate;       /* next expected state */
314
315	uint32_t *op;           /* current operation, NULL operations isn't known yet  */
316	uint32_t pstates[NS_MAX_PREVSTATES]; /* previous states */
317	uint16_t npstates;      /* number of previous states saved */
318	uint16_t stateidx;      /* current state index */
319
320	/* The simulated NAND flash pages array */
321	union ns_mem *pages;
322
323	/* Slab allocator for nand pages */
324	struct kmem_cache *nand_pages_slab;
325
326	/* Internal buffer of page + OOB size bytes */
327	union ns_mem buf;
328
329	/* NAND flash "geometry" */
330	struct {
331		uint64_t totsz;     /* total flash size, bytes */
332		uint32_t secsz;     /* flash sector (erase block) size, bytes */
333		uint pgsz;          /* NAND flash page size, bytes */
334		uint oobsz;         /* page OOB area size, bytes */
335		uint64_t totszoob;  /* total flash size including OOB, bytes */
336		uint pgszoob;       /* page size including OOB , bytes*/
337		uint secszoob;      /* sector size including OOB, bytes */
338		uint pgnum;         /* total number of pages */
339		uint pgsec;         /* number of pages per sector */
340		uint secshift;      /* bits number in sector size */
341		uint pgshift;       /* bits number in page size */
342		uint pgaddrbytes;   /* bytes per page address */
343		uint secaddrbytes;  /* bytes per sector address */
344		uint idbytes;       /* the number ID bytes that this chip outputs */
345	} geom;
346
347	/* NAND flash internal registers */
348	struct {
349		unsigned command; /* the command register */
350		u_char   status;  /* the status register */
351		uint     row;     /* the page number */
352		uint     column;  /* the offset within page */
353		uint     count;   /* internal counter */
354		uint     num;     /* number of bytes which must be processed */
355		uint     off;     /* fixed page offset */
356	} regs;
357
358	/* NAND flash lines state */
359        struct {
360                int ce;  /* chip Enable */
361                int cle; /* command Latch Enable */
362                int ale; /* address Latch Enable */
363                int wp;  /* write Protect */
364        } lines;
365
366	/* Fields needed when using a cache file */
367	struct file *cfile; /* Open file */
368	unsigned long *pages_written; /* Which pages have been written */
369	void *file_buf;
370	struct page *held_pages[NS_MAX_HELD_PAGES];
371	int held_cnt;
372
373	struct nandsim_debug_info dbg;
374};
375
376/*
377 * Operations array. To perform any operation the simulator must pass
378 * through the correspondent states chain.
379 */
380static struct nandsim_operations {
381	uint32_t reqopts;  /* options which are required to perform the operation */
382	uint32_t states[NS_OPER_STATES]; /* operation's states */
383} ops[NS_OPER_NUM] = {
384	/* Read page + OOB from the beginning */
385	{OPT_SMALLPAGE, {STATE_CMD_READ0 | ACTION_ZEROOFF, STATE_ADDR_PAGE | ACTION_CPY,
386			STATE_DATAOUT, STATE_READY}},
387	/* Read page + OOB from the second half */
388	{OPT_PAGE512_8BIT, {STATE_CMD_READ1 | ACTION_HALFOFF, STATE_ADDR_PAGE | ACTION_CPY,
389			STATE_DATAOUT, STATE_READY}},
390	/* Read OOB */
391	{OPT_SMALLPAGE, {STATE_CMD_READOOB | ACTION_OOBOFF, STATE_ADDR_PAGE | ACTION_CPY,
392			STATE_DATAOUT, STATE_READY}},
393	/* Program page starting from the beginning */
394	{OPT_ANY, {STATE_CMD_SEQIN, STATE_ADDR_PAGE, STATE_DATAIN,
395			STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
396	/* Program page starting from the beginning */
397	{OPT_SMALLPAGE, {STATE_CMD_READ0, STATE_CMD_SEQIN | ACTION_ZEROOFF, STATE_ADDR_PAGE,
398			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
399	/* Program page starting from the second half */
400	{OPT_PAGE512, {STATE_CMD_READ1, STATE_CMD_SEQIN | ACTION_HALFOFF, STATE_ADDR_PAGE,
401			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
402	/* Program OOB */
403	{OPT_SMALLPAGE, {STATE_CMD_READOOB, STATE_CMD_SEQIN | ACTION_OOBOFF, STATE_ADDR_PAGE,
404			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
405	/* Erase sector */
406	{OPT_ANY, {STATE_CMD_ERASE1, STATE_ADDR_SEC, STATE_CMD_ERASE2 | ACTION_SECERASE, STATE_READY}},
407	/* Read status */
408	{OPT_ANY, {STATE_CMD_STATUS, STATE_DATAOUT_STATUS, STATE_READY}},
409	/* Read ID */
410	{OPT_ANY, {STATE_CMD_READID, STATE_ADDR_ZERO, STATE_DATAOUT_ID, STATE_READY}},
411	/* Large page devices read page */
412	{OPT_LARGEPAGE, {STATE_CMD_READ0, STATE_ADDR_PAGE, STATE_CMD_READSTART | ACTION_CPY,
413			       STATE_DATAOUT, STATE_READY}},
414	/* Large page devices random page read */
415	{OPT_LARGEPAGE, {STATE_CMD_RNDOUT, STATE_ADDR_COLUMN, STATE_CMD_RNDOUTSTART | ACTION_CPY,
416			       STATE_DATAOUT, STATE_READY}},
417};
418
419struct weak_block {
420	struct list_head list;
421	unsigned int erase_block_no;
422	unsigned int max_erases;
423	unsigned int erases_done;
424};
425
426static LIST_HEAD(weak_blocks);
427
428struct weak_page {
429	struct list_head list;
430	unsigned int page_no;
431	unsigned int max_writes;
432	unsigned int writes_done;
433};
434
435static LIST_HEAD(weak_pages);
436
437struct grave_page {
438	struct list_head list;
439	unsigned int page_no;
440	unsigned int max_reads;
441	unsigned int reads_done;
442};
443
444static LIST_HEAD(grave_pages);
445
446static unsigned long *erase_block_wear = NULL;
447static unsigned int wear_eb_count = 0;
448static unsigned long total_wear = 0;
449
450/* MTD structure for NAND controller */
451static struct mtd_info *nsmtd;
452
453static int nandsim_debugfs_show(struct seq_file *m, void *private)
454{
455	unsigned long wmin = -1, wmax = 0, avg;
456	unsigned long deciles[10], decile_max[10], tot = 0;
457	unsigned int i;
458
459	/* Calc wear stats */
460	for (i = 0; i < wear_eb_count; ++i) {
461		unsigned long wear = erase_block_wear[i];
462		if (wear < wmin)
463			wmin = wear;
464		if (wear > wmax)
465			wmax = wear;
466		tot += wear;
467	}
468
469	for (i = 0; i < 9; ++i) {
470		deciles[i] = 0;
471		decile_max[i] = (wmax * (i + 1) + 5) / 10;
472	}
473	deciles[9] = 0;
474	decile_max[9] = wmax;
475	for (i = 0; i < wear_eb_count; ++i) {
476		int d;
477		unsigned long wear = erase_block_wear[i];
478		for (d = 0; d < 10; ++d)
479			if (wear <= decile_max[d]) {
480				deciles[d] += 1;
481				break;
482			}
483	}
484	avg = tot / wear_eb_count;
485
486	/* Output wear report */
487	seq_printf(m, "Total numbers of erases:  %lu\n", tot);
488	seq_printf(m, "Number of erase blocks:   %u\n", wear_eb_count);
489	seq_printf(m, "Average number of erases: %lu\n", avg);
490	seq_printf(m, "Maximum number of erases: %lu\n", wmax);
491	seq_printf(m, "Minimum number of erases: %lu\n", wmin);
492	for (i = 0; i < 10; ++i) {
493		unsigned long from = (i ? decile_max[i - 1] + 1 : 0);
494		if (from > decile_max[i])
495			continue;
496		seq_printf(m, "Number of ebs with erase counts from %lu to %lu : %lu\n",
497			from,
498			decile_max[i],
499			deciles[i]);
500	}
501
502	return 0;
503}
504
505static int nandsim_debugfs_open(struct inode *inode, struct file *file)
506{
507	return single_open(file, nandsim_debugfs_show, inode->i_private);
508}
509
510static const struct file_operations dfs_fops = {
511	.open		= nandsim_debugfs_open,
512	.read		= seq_read,
513	.llseek		= seq_lseek,
514	.release	= single_release,
515};
516
517/**
518 * nandsim_debugfs_create - initialize debugfs
519 * @dev: nandsim device description object
520 *
521 * This function creates all debugfs files for UBI device @ubi. Returns zero in
522 * case of success and a negative error code in case of failure.
523 */
524static int nandsim_debugfs_create(struct nandsim *dev)
525{
526	struct nandsim_debug_info *dbg = &dev->dbg;
527	struct dentry *dent;
528	int err;
529
530	if (!IS_ENABLED(CONFIG_DEBUG_FS))
531		return 0;
532
533	dent = debugfs_create_dir("nandsim", NULL);
534	if (IS_ERR_OR_NULL(dent)) {
535		int err = dent ? -ENODEV : PTR_ERR(dent);
536
537		NS_ERR("cannot create \"nandsim\" debugfs directory, err %d\n",
538			err);
539		return err;
540	}
541	dbg->dfs_root = dent;
542
543	dent = debugfs_create_file("wear_report", S_IRUSR,
544				   dbg->dfs_root, dev, &dfs_fops);
545	if (IS_ERR_OR_NULL(dent))
546		goto out_remove;
547	dbg->dfs_wear_report = dent;
548
549	return 0;
550
551out_remove:
552	debugfs_remove_recursive(dbg->dfs_root);
553	err = dent ? PTR_ERR(dent) : -ENODEV;
554	return err;
555}
556
557/**
558 * nandsim_debugfs_remove - destroy all debugfs files
559 */
560static void nandsim_debugfs_remove(struct nandsim *ns)
561{
562	if (IS_ENABLED(CONFIG_DEBUG_FS))
563		debugfs_remove_recursive(ns->dbg.dfs_root);
564}
565
566/*
567 * Allocate array of page pointers, create slab allocation for an array
568 * and initialize the array by NULL pointers.
569 *
570 * RETURNS: 0 if success, -ENOMEM if memory alloc fails.
571 */
572static int alloc_device(struct nandsim *ns)
573{
574	struct file *cfile;
575	int i, err;
576
577	if (cache_file) {
578		cfile = filp_open(cache_file, O_CREAT | O_RDWR | O_LARGEFILE, 0600);
579		if (IS_ERR(cfile))
580			return PTR_ERR(cfile);
581		if (!(cfile->f_mode & FMODE_CAN_READ)) {
582			NS_ERR("alloc_device: cache file not readable\n");
583			err = -EINVAL;
584			goto err_close;
585		}
586		if (!(cfile->f_mode & FMODE_CAN_WRITE)) {
587			NS_ERR("alloc_device: cache file not writeable\n");
588			err = -EINVAL;
589			goto err_close;
590		}
591		ns->pages_written = vzalloc(BITS_TO_LONGS(ns->geom.pgnum) *
592					    sizeof(unsigned long));
593		if (!ns->pages_written) {
594			NS_ERR("alloc_device: unable to allocate pages written array\n");
595			err = -ENOMEM;
596			goto err_close;
597		}
598		ns->file_buf = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
599		if (!ns->file_buf) {
600			NS_ERR("alloc_device: unable to allocate file buf\n");
601			err = -ENOMEM;
602			goto err_free;
603		}
604		ns->cfile = cfile;
605		return 0;
606	}
607
608	ns->pages = vmalloc(ns->geom.pgnum * sizeof(union ns_mem));
609	if (!ns->pages) {
610		NS_ERR("alloc_device: unable to allocate page array\n");
611		return -ENOMEM;
612	}
613	for (i = 0; i < ns->geom.pgnum; i++) {
614		ns->pages[i].byte = NULL;
615	}
616	ns->nand_pages_slab = kmem_cache_create("nandsim",
617						ns->geom.pgszoob, 0, 0, NULL);
618	if (!ns->nand_pages_slab) {
619		NS_ERR("cache_create: unable to create kmem_cache\n");
620		return -ENOMEM;
621	}
622
623	return 0;
624
625err_free:
626	vfree(ns->pages_written);
627err_close:
628	filp_close(cfile, NULL);
629	return err;
630}
631
632/*
633 * Free any allocated pages, and free the array of page pointers.
634 */
635static void free_device(struct nandsim *ns)
636{
637	int i;
638
639	if (ns->cfile) {
640		kfree(ns->file_buf);
641		vfree(ns->pages_written);
642		filp_close(ns->cfile, NULL);
643		return;
644	}
645
646	if (ns->pages) {
647		for (i = 0; i < ns->geom.pgnum; i++) {
648			if (ns->pages[i].byte)
649				kmem_cache_free(ns->nand_pages_slab,
650						ns->pages[i].byte);
651		}
652		kmem_cache_destroy(ns->nand_pages_slab);
653		vfree(ns->pages);
654	}
655}
656
657static char *get_partition_name(int i)
658{
659	return kasprintf(GFP_KERNEL, "NAND simulator partition %d", i);
660}
661
662/*
663 * Initialize the nandsim structure.
664 *
665 * RETURNS: 0 if success, -ERRNO if failure.
666 */
667static int init_nandsim(struct mtd_info *mtd)
668{
669	struct nand_chip *chip = mtd->priv;
670	struct nandsim   *ns   = chip->priv;
671	int i, ret = 0;
672	uint64_t remains;
673	uint64_t next_offset;
674
675	if (NS_IS_INITIALIZED(ns)) {
676		NS_ERR("init_nandsim: nandsim is already initialized\n");
677		return -EIO;
678	}
679
680	/* Force mtd to not do delays */
681	chip->chip_delay = 0;
682
683	/* Initialize the NAND flash parameters */
684	ns->busw = chip->options & NAND_BUSWIDTH_16 ? 16 : 8;
685	ns->geom.totsz    = mtd->size;
686	ns->geom.pgsz     = mtd->writesize;
687	ns->geom.oobsz    = mtd->oobsize;
688	ns->geom.secsz    = mtd->erasesize;
689	ns->geom.pgszoob  = ns->geom.pgsz + ns->geom.oobsz;
690	ns->geom.pgnum    = div_u64(ns->geom.totsz, ns->geom.pgsz);
691	ns->geom.totszoob = ns->geom.totsz + (uint64_t)ns->geom.pgnum * ns->geom.oobsz;
692	ns->geom.secshift = ffs(ns->geom.secsz) - 1;
693	ns->geom.pgshift  = chip->page_shift;
694	ns->geom.pgsec    = ns->geom.secsz / ns->geom.pgsz;
695	ns->geom.secszoob = ns->geom.secsz + ns->geom.oobsz * ns->geom.pgsec;
696	ns->options = 0;
697
698	if (ns->geom.pgsz == 512) {
699		ns->options |= OPT_PAGE512;
700		if (ns->busw == 8)
701			ns->options |= OPT_PAGE512_8BIT;
702	} else if (ns->geom.pgsz == 2048) {
703		ns->options |= OPT_PAGE2048;
704	} else if (ns->geom.pgsz == 4096) {
705		ns->options |= OPT_PAGE4096;
706	} else {
707		NS_ERR("init_nandsim: unknown page size %u\n", ns->geom.pgsz);
708		return -EIO;
709	}
710
711	if (ns->options & OPT_SMALLPAGE) {
712		if (ns->geom.totsz <= (32 << 20)) {
713			ns->geom.pgaddrbytes  = 3;
714			ns->geom.secaddrbytes = 2;
715		} else {
716			ns->geom.pgaddrbytes  = 4;
717			ns->geom.secaddrbytes = 3;
718		}
719	} else {
720		if (ns->geom.totsz <= (128 << 20)) {
721			ns->geom.pgaddrbytes  = 4;
722			ns->geom.secaddrbytes = 2;
723		} else {
724			ns->geom.pgaddrbytes  = 5;
725			ns->geom.secaddrbytes = 3;
726		}
727	}
728
729	/* Fill the partition_info structure */
730	if (parts_num > ARRAY_SIZE(ns->partitions)) {
731		NS_ERR("too many partitions.\n");
732		return -EINVAL;
733	}
734	remains = ns->geom.totsz;
735	next_offset = 0;
736	for (i = 0; i < parts_num; ++i) {
737		uint64_t part_sz = (uint64_t)parts[i] * ns->geom.secsz;
738
739		if (!part_sz || part_sz > remains) {
740			NS_ERR("bad partition size.\n");
741			return -EINVAL;
742		}
743		ns->partitions[i].name   = get_partition_name(i);
744		if (!ns->partitions[i].name) {
745			NS_ERR("unable to allocate memory.\n");
746			return -ENOMEM;
747		}
748		ns->partitions[i].offset = next_offset;
749		ns->partitions[i].size   = part_sz;
750		next_offset += ns->partitions[i].size;
751		remains -= ns->partitions[i].size;
752	}
753	ns->nbparts = parts_num;
754	if (remains) {
755		if (parts_num + 1 > ARRAY_SIZE(ns->partitions)) {
756			NS_ERR("too many partitions.\n");
757			return -EINVAL;
758		}
759		ns->partitions[i].name   = get_partition_name(i);
760		if (!ns->partitions[i].name) {
761			NS_ERR("unable to allocate memory.\n");
762			return -ENOMEM;
763		}
764		ns->partitions[i].offset = next_offset;
765		ns->partitions[i].size   = remains;
766		ns->nbparts += 1;
767	}
768
769	if (ns->busw == 16)
770		NS_WARN("16-bit flashes support wasn't tested\n");
771
772	printk("flash size: %llu MiB\n",
773			(unsigned long long)ns->geom.totsz >> 20);
774	printk("page size: %u bytes\n",         ns->geom.pgsz);
775	printk("OOB area size: %u bytes\n",     ns->geom.oobsz);
776	printk("sector size: %u KiB\n",         ns->geom.secsz >> 10);
777	printk("pages number: %u\n",            ns->geom.pgnum);
778	printk("pages per sector: %u\n",        ns->geom.pgsec);
779	printk("bus width: %u\n",               ns->busw);
780	printk("bits in sector size: %u\n",     ns->geom.secshift);
781	printk("bits in page size: %u\n",       ns->geom.pgshift);
782	printk("bits in OOB size: %u\n",	ffs(ns->geom.oobsz) - 1);
783	printk("flash size with OOB: %llu KiB\n",
784			(unsigned long long)ns->geom.totszoob >> 10);
785	printk("page address bytes: %u\n",      ns->geom.pgaddrbytes);
786	printk("sector address bytes: %u\n",    ns->geom.secaddrbytes);
787	printk("options: %#x\n",                ns->options);
788
789	if ((ret = alloc_device(ns)) != 0)
790		return ret;
791
792	/* Allocate / initialize the internal buffer */
793	ns->buf.byte = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
794	if (!ns->buf.byte) {
795		NS_ERR("init_nandsim: unable to allocate %u bytes for the internal buffer\n",
796			ns->geom.pgszoob);
797		return -ENOMEM;
798	}
799	memset(ns->buf.byte, 0xFF, ns->geom.pgszoob);
800
801	return 0;
802}
803
804/*
805 * Free the nandsim structure.
806 */
807static void free_nandsim(struct nandsim *ns)
808{
809	kfree(ns->buf.byte);
810	free_device(ns);
811
812	return;
813}
814
815static int parse_badblocks(struct nandsim *ns, struct mtd_info *mtd)
816{
817	char *w;
818	int zero_ok;
819	unsigned int erase_block_no;
820	loff_t offset;
821
822	if (!badblocks)
823		return 0;
824	w = badblocks;
825	do {
826		zero_ok = (*w == '0' ? 1 : 0);
827		erase_block_no = simple_strtoul(w, &w, 0);
828		if (!zero_ok && !erase_block_no) {
829			NS_ERR("invalid badblocks.\n");
830			return -EINVAL;
831		}
832		offset = (loff_t)erase_block_no * ns->geom.secsz;
833		if (mtd_block_markbad(mtd, offset)) {
834			NS_ERR("invalid badblocks.\n");
835			return -EINVAL;
836		}
837		if (*w == ',')
838			w += 1;
839	} while (*w);
840	return 0;
841}
842
843static int parse_weakblocks(void)
844{
845	char *w;
846	int zero_ok;
847	unsigned int erase_block_no;
848	unsigned int max_erases;
849	struct weak_block *wb;
850
851	if (!weakblocks)
852		return 0;
853	w = weakblocks;
854	do {
855		zero_ok = (*w == '0' ? 1 : 0);
856		erase_block_no = simple_strtoul(w, &w, 0);
857		if (!zero_ok && !erase_block_no) {
858			NS_ERR("invalid weakblocks.\n");
859			return -EINVAL;
860		}
861		max_erases = 3;
862		if (*w == ':') {
863			w += 1;
864			max_erases = simple_strtoul(w, &w, 0);
865		}
866		if (*w == ',')
867			w += 1;
868		wb = kzalloc(sizeof(*wb), GFP_KERNEL);
869		if (!wb) {
870			NS_ERR("unable to allocate memory.\n");
871			return -ENOMEM;
872		}
873		wb->erase_block_no = erase_block_no;
874		wb->max_erases = max_erases;
875		list_add(&wb->list, &weak_blocks);
876	} while (*w);
877	return 0;
878}
879
880static int erase_error(unsigned int erase_block_no)
881{
882	struct weak_block *wb;
883
884	list_for_each_entry(wb, &weak_blocks, list)
885		if (wb->erase_block_no == erase_block_no) {
886			if (wb->erases_done >= wb->max_erases)
887				return 1;
888			wb->erases_done += 1;
889			return 0;
890		}
891	return 0;
892}
893
894static int parse_weakpages(void)
895{
896	char *w;
897	int zero_ok;
898	unsigned int page_no;
899	unsigned int max_writes;
900	struct weak_page *wp;
901
902	if (!weakpages)
903		return 0;
904	w = weakpages;
905	do {
906		zero_ok = (*w == '0' ? 1 : 0);
907		page_no = simple_strtoul(w, &w, 0);
908		if (!zero_ok && !page_no) {
909			NS_ERR("invalid weakpagess.\n");
910			return -EINVAL;
911		}
912		max_writes = 3;
913		if (*w == ':') {
914			w += 1;
915			max_writes = simple_strtoul(w, &w, 0);
916		}
917		if (*w == ',')
918			w += 1;
919		wp = kzalloc(sizeof(*wp), GFP_KERNEL);
920		if (!wp) {
921			NS_ERR("unable to allocate memory.\n");
922			return -ENOMEM;
923		}
924		wp->page_no = page_no;
925		wp->max_writes = max_writes;
926		list_add(&wp->list, &weak_pages);
927	} while (*w);
928	return 0;
929}
930
931static int write_error(unsigned int page_no)
932{
933	struct weak_page *wp;
934
935	list_for_each_entry(wp, &weak_pages, list)
936		if (wp->page_no == page_no) {
937			if (wp->writes_done >= wp->max_writes)
938				return 1;
939			wp->writes_done += 1;
940			return 0;
941		}
942	return 0;
943}
944
945static int parse_gravepages(void)
946{
947	char *g;
948	int zero_ok;
949	unsigned int page_no;
950	unsigned int max_reads;
951	struct grave_page *gp;
952
953	if (!gravepages)
954		return 0;
955	g = gravepages;
956	do {
957		zero_ok = (*g == '0' ? 1 : 0);
958		page_no = simple_strtoul(g, &g, 0);
959		if (!zero_ok && !page_no) {
960			NS_ERR("invalid gravepagess.\n");
961			return -EINVAL;
962		}
963		max_reads = 3;
964		if (*g == ':') {
965			g += 1;
966			max_reads = simple_strtoul(g, &g, 0);
967		}
968		if (*g == ',')
969			g += 1;
970		gp = kzalloc(sizeof(*gp), GFP_KERNEL);
971		if (!gp) {
972			NS_ERR("unable to allocate memory.\n");
973			return -ENOMEM;
974		}
975		gp->page_no = page_no;
976		gp->max_reads = max_reads;
977		list_add(&gp->list, &grave_pages);
978	} while (*g);
979	return 0;
980}
981
982static int read_error(unsigned int page_no)
983{
984	struct grave_page *gp;
985
986	list_for_each_entry(gp, &grave_pages, list)
987		if (gp->page_no == page_no) {
988			if (gp->reads_done >= gp->max_reads)
989				return 1;
990			gp->reads_done += 1;
991			return 0;
992		}
993	return 0;
994}
995
996static void free_lists(void)
997{
998	struct list_head *pos, *n;
999	list_for_each_safe(pos, n, &weak_blocks) {
1000		list_del(pos);
1001		kfree(list_entry(pos, struct weak_block, list));
1002	}
1003	list_for_each_safe(pos, n, &weak_pages) {
1004		list_del(pos);
1005		kfree(list_entry(pos, struct weak_page, list));
1006	}
1007	list_for_each_safe(pos, n, &grave_pages) {
1008		list_del(pos);
1009		kfree(list_entry(pos, struct grave_page, list));
1010	}
1011	kfree(erase_block_wear);
1012}
1013
1014static int setup_wear_reporting(struct mtd_info *mtd)
1015{
1016	size_t mem;
1017
1018	wear_eb_count = div_u64(mtd->size, mtd->erasesize);
1019	mem = wear_eb_count * sizeof(unsigned long);
1020	if (mem / sizeof(unsigned long) != wear_eb_count) {
1021		NS_ERR("Too many erase blocks for wear reporting\n");
1022		return -ENOMEM;
1023	}
1024	erase_block_wear = kzalloc(mem, GFP_KERNEL);
1025	if (!erase_block_wear) {
1026		NS_ERR("Too many erase blocks for wear reporting\n");
1027		return -ENOMEM;
1028	}
1029	return 0;
1030}
1031
1032static void update_wear(unsigned int erase_block_no)
1033{
1034	if (!erase_block_wear)
1035		return;
1036	total_wear += 1;
1037	/*
1038	 * TODO: Notify this through a debugfs entry,
1039	 * instead of showing an error message.
1040	 */
1041	if (total_wear == 0)
1042		NS_ERR("Erase counter total overflow\n");
1043	erase_block_wear[erase_block_no] += 1;
1044	if (erase_block_wear[erase_block_no] == 0)
1045		NS_ERR("Erase counter overflow for erase block %u\n", erase_block_no);
1046}
1047
1048/*
1049 * Returns the string representation of 'state' state.
1050 */
1051static char *get_state_name(uint32_t state)
1052{
1053	switch (NS_STATE(state)) {
1054		case STATE_CMD_READ0:
1055			return "STATE_CMD_READ0";
1056		case STATE_CMD_READ1:
1057			return "STATE_CMD_READ1";
1058		case STATE_CMD_PAGEPROG:
1059			return "STATE_CMD_PAGEPROG";
1060		case STATE_CMD_READOOB:
1061			return "STATE_CMD_READOOB";
1062		case STATE_CMD_READSTART:
1063			return "STATE_CMD_READSTART";
1064		case STATE_CMD_ERASE1:
1065			return "STATE_CMD_ERASE1";
1066		case STATE_CMD_STATUS:
1067			return "STATE_CMD_STATUS";
1068		case STATE_CMD_SEQIN:
1069			return "STATE_CMD_SEQIN";
1070		case STATE_CMD_READID:
1071			return "STATE_CMD_READID";
1072		case STATE_CMD_ERASE2:
1073			return "STATE_CMD_ERASE2";
1074		case STATE_CMD_RESET:
1075			return "STATE_CMD_RESET";
1076		case STATE_CMD_RNDOUT:
1077			return "STATE_CMD_RNDOUT";
1078		case STATE_CMD_RNDOUTSTART:
1079			return "STATE_CMD_RNDOUTSTART";
1080		case STATE_ADDR_PAGE:
1081			return "STATE_ADDR_PAGE";
1082		case STATE_ADDR_SEC:
1083			return "STATE_ADDR_SEC";
1084		case STATE_ADDR_ZERO:
1085			return "STATE_ADDR_ZERO";
1086		case STATE_ADDR_COLUMN:
1087			return "STATE_ADDR_COLUMN";
1088		case STATE_DATAIN:
1089			return "STATE_DATAIN";
1090		case STATE_DATAOUT:
1091			return "STATE_DATAOUT";
1092		case STATE_DATAOUT_ID:
1093			return "STATE_DATAOUT_ID";
1094		case STATE_DATAOUT_STATUS:
1095			return "STATE_DATAOUT_STATUS";
1096		case STATE_READY:
1097			return "STATE_READY";
1098		case STATE_UNKNOWN:
1099			return "STATE_UNKNOWN";
1100	}
1101
1102	NS_ERR("get_state_name: unknown state, BUG\n");
1103	return NULL;
1104}
1105
1106/*
1107 * Check if command is valid.
1108 *
1109 * RETURNS: 1 if wrong command, 0 if right.
1110 */
1111static int check_command(int cmd)
1112{
1113	switch (cmd) {
1114
1115	case NAND_CMD_READ0:
1116	case NAND_CMD_READ1:
1117	case NAND_CMD_READSTART:
1118	case NAND_CMD_PAGEPROG:
1119	case NAND_CMD_READOOB:
1120	case NAND_CMD_ERASE1:
1121	case NAND_CMD_STATUS:
1122	case NAND_CMD_SEQIN:
1123	case NAND_CMD_READID:
1124	case NAND_CMD_ERASE2:
1125	case NAND_CMD_RESET:
1126	case NAND_CMD_RNDOUT:
1127	case NAND_CMD_RNDOUTSTART:
1128		return 0;
1129
1130	default:
1131		return 1;
1132	}
1133}
1134
1135/*
1136 * Returns state after command is accepted by command number.
1137 */
1138static uint32_t get_state_by_command(unsigned command)
1139{
1140	switch (command) {
1141		case NAND_CMD_READ0:
1142			return STATE_CMD_READ0;
1143		case NAND_CMD_READ1:
1144			return STATE_CMD_READ1;
1145		case NAND_CMD_PAGEPROG:
1146			return STATE_CMD_PAGEPROG;
1147		case NAND_CMD_READSTART:
1148			return STATE_CMD_READSTART;
1149		case NAND_CMD_READOOB:
1150			return STATE_CMD_READOOB;
1151		case NAND_CMD_ERASE1:
1152			return STATE_CMD_ERASE1;
1153		case NAND_CMD_STATUS:
1154			return STATE_CMD_STATUS;
1155		case NAND_CMD_SEQIN:
1156			return STATE_CMD_SEQIN;
1157		case NAND_CMD_READID:
1158			return STATE_CMD_READID;
1159		case NAND_CMD_ERASE2:
1160			return STATE_CMD_ERASE2;
1161		case NAND_CMD_RESET:
1162			return STATE_CMD_RESET;
1163		case NAND_CMD_RNDOUT:
1164			return STATE_CMD_RNDOUT;
1165		case NAND_CMD_RNDOUTSTART:
1166			return STATE_CMD_RNDOUTSTART;
1167	}
1168
1169	NS_ERR("get_state_by_command: unknown command, BUG\n");
1170	return 0;
1171}
1172
1173/*
1174 * Move an address byte to the correspondent internal register.
1175 */
1176static inline void accept_addr_byte(struct nandsim *ns, u_char bt)
1177{
1178	uint byte = (uint)bt;
1179
1180	if (ns->regs.count < (ns->geom.pgaddrbytes - ns->geom.secaddrbytes))
1181		ns->regs.column |= (byte << 8 * ns->regs.count);
1182	else {
1183		ns->regs.row |= (byte << 8 * (ns->regs.count -
1184						ns->geom.pgaddrbytes +
1185						ns->geom.secaddrbytes));
1186	}
1187
1188	return;
1189}
1190
1191/*
1192 * Switch to STATE_READY state.
1193 */
1194static inline void switch_to_ready_state(struct nandsim *ns, u_char status)
1195{
1196	NS_DBG("switch_to_ready_state: switch to %s state\n", get_state_name(STATE_READY));
1197
1198	ns->state       = STATE_READY;
1199	ns->nxstate     = STATE_UNKNOWN;
1200	ns->op          = NULL;
1201	ns->npstates    = 0;
1202	ns->stateidx    = 0;
1203	ns->regs.num    = 0;
1204	ns->regs.count  = 0;
1205	ns->regs.off    = 0;
1206	ns->regs.row    = 0;
1207	ns->regs.column = 0;
1208	ns->regs.status = status;
1209}
1210
1211/*
1212 * If the operation isn't known yet, try to find it in the global array
1213 * of supported operations.
1214 *
1215 * Operation can be unknown because of the following.
1216 *   1. New command was accepted and this is the first call to find the
1217 *      correspondent states chain. In this case ns->npstates = 0;
1218 *   2. There are several operations which begin with the same command(s)
1219 *      (for example program from the second half and read from the
1220 *      second half operations both begin with the READ1 command). In this
1221 *      case the ns->pstates[] array contains previous states.
1222 *
1223 * Thus, the function tries to find operation containing the following
1224 * states (if the 'flag' parameter is 0):
1225 *    ns->pstates[0], ... ns->pstates[ns->npstates], ns->state
1226 *
1227 * If (one and only one) matching operation is found, it is accepted (
1228 * ns->ops, ns->state, ns->nxstate are initialized, ns->npstate is
1229 * zeroed).
1230 *
1231 * If there are several matches, the current state is pushed to the
1232 * ns->pstates.
1233 *
1234 * The operation can be unknown only while commands are input to the chip.
1235 * As soon as address command is accepted, the operation must be known.
1236 * In such situation the function is called with 'flag' != 0, and the
1237 * operation is searched using the following pattern:
1238 *     ns->pstates[0], ... ns->pstates[ns->npstates], <address input>
1239 *
1240 * It is supposed that this pattern must either match one operation or
1241 * none. There can't be ambiguity in that case.
1242 *
1243 * If no matches found, the function does the following:
1244 *   1. if there are saved states present, try to ignore them and search
1245 *      again only using the last command. If nothing was found, switch
1246 *      to the STATE_READY state.
1247 *   2. if there are no saved states, switch to the STATE_READY state.
1248 *
1249 * RETURNS: -2 - no matched operations found.
1250 *          -1 - several matches.
1251 *           0 - operation is found.
1252 */
1253static int find_operation(struct nandsim *ns, uint32_t flag)
1254{
1255	int opsfound = 0;
1256	int i, j, idx = 0;
1257
1258	for (i = 0; i < NS_OPER_NUM; i++) {
1259
1260		int found = 1;
1261
1262		if (!(ns->options & ops[i].reqopts))
1263			/* Ignore operations we can't perform */
1264			continue;
1265
1266		if (flag) {
1267			if (!(ops[i].states[ns->npstates] & STATE_ADDR_MASK))
1268				continue;
1269		} else {
1270			if (NS_STATE(ns->state) != NS_STATE(ops[i].states[ns->npstates]))
1271				continue;
1272		}
1273
1274		for (j = 0; j < ns->npstates; j++)
1275			if (NS_STATE(ops[i].states[j]) != NS_STATE(ns->pstates[j])
1276				&& (ns->options & ops[idx].reqopts)) {
1277				found = 0;
1278				break;
1279			}
1280
1281		if (found) {
1282			idx = i;
1283			opsfound += 1;
1284		}
1285	}
1286
1287	if (opsfound == 1) {
1288		/* Exact match */
1289		ns->op = &ops[idx].states[0];
1290		if (flag) {
1291			/*
1292			 * In this case the find_operation function was
1293			 * called when address has just began input. But it isn't
1294			 * yet fully input and the current state must
1295			 * not be one of STATE_ADDR_*, but the STATE_ADDR_*
1296			 * state must be the next state (ns->nxstate).
1297			 */
1298			ns->stateidx = ns->npstates - 1;
1299		} else {
1300			ns->stateidx = ns->npstates;
1301		}
1302		ns->npstates = 0;
1303		ns->state = ns->op[ns->stateidx];
1304		ns->nxstate = ns->op[ns->stateidx + 1];
1305		NS_DBG("find_operation: operation found, index: %d, state: %s, nxstate %s\n",
1306				idx, get_state_name(ns->state), get_state_name(ns->nxstate));
1307		return 0;
1308	}
1309
1310	if (opsfound == 0) {
1311		/* Nothing was found. Try to ignore previous commands (if any) and search again */
1312		if (ns->npstates != 0) {
1313			NS_DBG("find_operation: no operation found, try again with state %s\n",
1314					get_state_name(ns->state));
1315			ns->npstates = 0;
1316			return find_operation(ns, 0);
1317
1318		}
1319		NS_DBG("find_operation: no operations found\n");
1320		switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1321		return -2;
1322	}
1323
1324	if (flag) {
1325		/* This shouldn't happen */
1326		NS_DBG("find_operation: BUG, operation must be known if address is input\n");
1327		return -2;
1328	}
1329
1330	NS_DBG("find_operation: there is still ambiguity\n");
1331
1332	ns->pstates[ns->npstates++] = ns->state;
1333
1334	return -1;
1335}
1336
1337static void put_pages(struct nandsim *ns)
1338{
1339	int i;
1340
1341	for (i = 0; i < ns->held_cnt; i++)
1342		page_cache_release(ns->held_pages[i]);
1343}
1344
1345/* Get page cache pages in advance to provide NOFS memory allocation */
1346static int get_pages(struct nandsim *ns, struct file *file, size_t count, loff_t pos)
1347{
1348	pgoff_t index, start_index, end_index;
1349	struct page *page;
1350	struct address_space *mapping = file->f_mapping;
1351
1352	start_index = pos >> PAGE_CACHE_SHIFT;
1353	end_index = (pos + count - 1) >> PAGE_CACHE_SHIFT;
1354	if (end_index - start_index + 1 > NS_MAX_HELD_PAGES)
1355		return -EINVAL;
1356	ns->held_cnt = 0;
1357	for (index = start_index; index <= end_index; index++) {
1358		page = find_get_page(mapping, index);
1359		if (page == NULL) {
1360			page = find_or_create_page(mapping, index, GFP_NOFS);
1361			if (page == NULL) {
1362				write_inode_now(mapping->host, 1);
1363				page = find_or_create_page(mapping, index, GFP_NOFS);
1364			}
1365			if (page == NULL) {
1366				put_pages(ns);
1367				return -ENOMEM;
1368			}
1369			unlock_page(page);
1370		}
1371		ns->held_pages[ns->held_cnt++] = page;
1372	}
1373	return 0;
1374}
1375
1376static int set_memalloc(void)
1377{
1378	if (current->flags & PF_MEMALLOC)
1379		return 0;
1380	current->flags |= PF_MEMALLOC;
1381	return 1;
1382}
1383
1384static void clear_memalloc(int memalloc)
1385{
1386	if (memalloc)
1387		current->flags &= ~PF_MEMALLOC;
1388}
1389
1390static ssize_t read_file(struct nandsim *ns, struct file *file, void *buf, size_t count, loff_t pos)
1391{
1392	ssize_t tx;
1393	int err, memalloc;
1394
1395	err = get_pages(ns, file, count, pos);
1396	if (err)
1397		return err;
1398	memalloc = set_memalloc();
1399	tx = kernel_read(file, pos, buf, count);
1400	clear_memalloc(memalloc);
1401	put_pages(ns);
1402	return tx;
1403}
1404
1405static ssize_t write_file(struct nandsim *ns, struct file *file, void *buf, size_t count, loff_t pos)
1406{
1407	ssize_t tx;
1408	int err, memalloc;
1409
1410	err = get_pages(ns, file, count, pos);
1411	if (err)
1412		return err;
1413	memalloc = set_memalloc();
1414	tx = kernel_write(file, buf, count, pos);
1415	clear_memalloc(memalloc);
1416	put_pages(ns);
1417	return tx;
1418}
1419
1420/*
1421 * Returns a pointer to the current page.
1422 */
1423static inline union ns_mem *NS_GET_PAGE(struct nandsim *ns)
1424{
1425	return &(ns->pages[ns->regs.row]);
1426}
1427
1428/*
1429 * Retuns a pointer to the current byte, within the current page.
1430 */
1431static inline u_char *NS_PAGE_BYTE_OFF(struct nandsim *ns)
1432{
1433	return NS_GET_PAGE(ns)->byte + ns->regs.column + ns->regs.off;
1434}
1435
1436static int do_read_error(struct nandsim *ns, int num)
1437{
1438	unsigned int page_no = ns->regs.row;
1439
1440	if (read_error(page_no)) {
1441		prandom_bytes(ns->buf.byte, num);
1442		NS_WARN("simulating read error in page %u\n", page_no);
1443		return 1;
1444	}
1445	return 0;
1446}
1447
1448static void do_bit_flips(struct nandsim *ns, int num)
1449{
1450	if (bitflips && prandom_u32() < (1 << 22)) {
1451		int flips = 1;
1452		if (bitflips > 1)
1453			flips = (prandom_u32() % (int) bitflips) + 1;
1454		while (flips--) {
1455			int pos = prandom_u32() % (num * 8);
1456			ns->buf.byte[pos / 8] ^= (1 << (pos % 8));
1457			NS_WARN("read_page: flipping bit %d in page %d "
1458				"reading from %d ecc: corrected=%u failed=%u\n",
1459				pos, ns->regs.row, ns->regs.column + ns->regs.off,
1460				nsmtd->ecc_stats.corrected, nsmtd->ecc_stats.failed);
1461		}
1462	}
1463}
1464
1465/*
1466 * Fill the NAND buffer with data read from the specified page.
1467 */
1468static void read_page(struct nandsim *ns, int num)
1469{
1470	union ns_mem *mypage;
1471
1472	if (ns->cfile) {
1473		if (!test_bit(ns->regs.row, ns->pages_written)) {
1474			NS_DBG("read_page: page %d not written\n", ns->regs.row);
1475			memset(ns->buf.byte, 0xFF, num);
1476		} else {
1477			loff_t pos;
1478			ssize_t tx;
1479
1480			NS_DBG("read_page: page %d written, reading from %d\n",
1481				ns->regs.row, ns->regs.column + ns->regs.off);
1482			if (do_read_error(ns, num))
1483				return;
1484			pos = (loff_t)NS_RAW_OFFSET(ns) + ns->regs.off;
1485			tx = read_file(ns, ns->cfile, ns->buf.byte, num, pos);
1486			if (tx != num) {
1487				NS_ERR("read_page: read error for page %d ret %ld\n", ns->regs.row, (long)tx);
1488				return;
1489			}
1490			do_bit_flips(ns, num);
1491		}
1492		return;
1493	}
1494
1495	mypage = NS_GET_PAGE(ns);
1496	if (mypage->byte == NULL) {
1497		NS_DBG("read_page: page %d not allocated\n", ns->regs.row);
1498		memset(ns->buf.byte, 0xFF, num);
1499	} else {
1500		NS_DBG("read_page: page %d allocated, reading from %d\n",
1501			ns->regs.row, ns->regs.column + ns->regs.off);
1502		if (do_read_error(ns, num))
1503			return;
1504		memcpy(ns->buf.byte, NS_PAGE_BYTE_OFF(ns), num);
1505		do_bit_flips(ns, num);
1506	}
1507}
1508
1509/*
1510 * Erase all pages in the specified sector.
1511 */
1512static void erase_sector(struct nandsim *ns)
1513{
1514	union ns_mem *mypage;
1515	int i;
1516
1517	if (ns->cfile) {
1518		for (i = 0; i < ns->geom.pgsec; i++)
1519			if (__test_and_clear_bit(ns->regs.row + i,
1520						 ns->pages_written)) {
1521				NS_DBG("erase_sector: freeing page %d\n", ns->regs.row + i);
1522			}
1523		return;
1524	}
1525
1526	mypage = NS_GET_PAGE(ns);
1527	for (i = 0; i < ns->geom.pgsec; i++) {
1528		if (mypage->byte != NULL) {
1529			NS_DBG("erase_sector: freeing page %d\n", ns->regs.row+i);
1530			kmem_cache_free(ns->nand_pages_slab, mypage->byte);
1531			mypage->byte = NULL;
1532		}
1533		mypage++;
1534	}
1535}
1536
1537/*
1538 * Program the specified page with the contents from the NAND buffer.
1539 */
1540static int prog_page(struct nandsim *ns, int num)
1541{
1542	int i;
1543	union ns_mem *mypage;
1544	u_char *pg_off;
1545
1546	if (ns->cfile) {
1547		loff_t off;
1548		ssize_t tx;
1549		int all;
1550
1551		NS_DBG("prog_page: writing page %d\n", ns->regs.row);
1552		pg_off = ns->file_buf + ns->regs.column + ns->regs.off;
1553		off = (loff_t)NS_RAW_OFFSET(ns) + ns->regs.off;
1554		if (!test_bit(ns->regs.row, ns->pages_written)) {
1555			all = 1;
1556			memset(ns->file_buf, 0xff, ns->geom.pgszoob);
1557		} else {
1558			all = 0;
1559			tx = read_file(ns, ns->cfile, pg_off, num, off);
1560			if (tx != num) {
1561				NS_ERR("prog_page: read error for page %d ret %ld\n", ns->regs.row, (long)tx);
1562				return -1;
1563			}
1564		}
1565		for (i = 0; i < num; i++)
1566			pg_off[i] &= ns->buf.byte[i];
1567		if (all) {
1568			loff_t pos = (loff_t)ns->regs.row * ns->geom.pgszoob;
1569			tx = write_file(ns, ns->cfile, ns->file_buf, ns->geom.pgszoob, pos);
1570			if (tx != ns->geom.pgszoob) {
1571				NS_ERR("prog_page: write error for page %d ret %ld\n", ns->regs.row, (long)tx);
1572				return -1;
1573			}
1574			__set_bit(ns->regs.row, ns->pages_written);
1575		} else {
1576			tx = write_file(ns, ns->cfile, pg_off, num, off);
1577			if (tx != num) {
1578				NS_ERR("prog_page: write error for page %d ret %ld\n", ns->regs.row, (long)tx);
1579				return -1;
1580			}
1581		}
1582		return 0;
1583	}
1584
1585	mypage = NS_GET_PAGE(ns);
1586	if (mypage->byte == NULL) {
1587		NS_DBG("prog_page: allocating page %d\n", ns->regs.row);
1588		/*
1589		 * We allocate memory with GFP_NOFS because a flash FS may
1590		 * utilize this. If it is holding an FS lock, then gets here,
1591		 * then kernel memory alloc runs writeback which goes to the FS
1592		 * again and deadlocks. This was seen in practice.
1593		 */
1594		mypage->byte = kmem_cache_alloc(ns->nand_pages_slab, GFP_NOFS);
1595		if (mypage->byte == NULL) {
1596			NS_ERR("prog_page: error allocating memory for page %d\n", ns->regs.row);
1597			return -1;
1598		}
1599		memset(mypage->byte, 0xFF, ns->geom.pgszoob);
1600	}
1601
1602	pg_off = NS_PAGE_BYTE_OFF(ns);
1603	for (i = 0; i < num; i++)
1604		pg_off[i] &= ns->buf.byte[i];
1605
1606	return 0;
1607}
1608
1609/*
1610 * If state has any action bit, perform this action.
1611 *
1612 * RETURNS: 0 if success, -1 if error.
1613 */
1614static int do_state_action(struct nandsim *ns, uint32_t action)
1615{
1616	int num;
1617	int busdiv = ns->busw == 8 ? 1 : 2;
1618	unsigned int erase_block_no, page_no;
1619
1620	action &= ACTION_MASK;
1621
1622	/* Check that page address input is correct */
1623	if (action != ACTION_SECERASE && ns->regs.row >= ns->geom.pgnum) {
1624		NS_WARN("do_state_action: wrong page number (%#x)\n", ns->regs.row);
1625		return -1;
1626	}
1627
1628	switch (action) {
1629
1630	case ACTION_CPY:
1631		/*
1632		 * Copy page data to the internal buffer.
1633		 */
1634
1635		/* Column shouldn't be very large */
1636		if (ns->regs.column >= (ns->geom.pgszoob - ns->regs.off)) {
1637			NS_ERR("do_state_action: column number is too large\n");
1638			break;
1639		}
1640		num = ns->geom.pgszoob - ns->regs.off - ns->regs.column;
1641		read_page(ns, num);
1642
1643		NS_DBG("do_state_action: (ACTION_CPY:) copy %d bytes to int buf, raw offset %d\n",
1644			num, NS_RAW_OFFSET(ns) + ns->regs.off);
1645
1646		if (ns->regs.off == 0)
1647			NS_LOG("read page %d\n", ns->regs.row);
1648		else if (ns->regs.off < ns->geom.pgsz)
1649			NS_LOG("read page %d (second half)\n", ns->regs.row);
1650		else
1651			NS_LOG("read OOB of page %d\n", ns->regs.row);
1652
1653		NS_UDELAY(access_delay);
1654		NS_UDELAY(input_cycle * ns->geom.pgsz / 1000 / busdiv);
1655
1656		break;
1657
1658	case ACTION_SECERASE:
1659		/*
1660		 * Erase sector.
1661		 */
1662
1663		if (ns->lines.wp) {
1664			NS_ERR("do_state_action: device is write-protected, ignore sector erase\n");
1665			return -1;
1666		}
1667
1668		if (ns->regs.row >= ns->geom.pgnum - ns->geom.pgsec
1669			|| (ns->regs.row & ~(ns->geom.secsz - 1))) {
1670			NS_ERR("do_state_action: wrong sector address (%#x)\n", ns->regs.row);
1671			return -1;
1672		}
1673
1674		ns->regs.row = (ns->regs.row <<
1675				8 * (ns->geom.pgaddrbytes - ns->geom.secaddrbytes)) | ns->regs.column;
1676		ns->regs.column = 0;
1677
1678		erase_block_no = ns->regs.row >> (ns->geom.secshift - ns->geom.pgshift);
1679
1680		NS_DBG("do_state_action: erase sector at address %#x, off = %d\n",
1681				ns->regs.row, NS_RAW_OFFSET(ns));
1682		NS_LOG("erase sector %u\n", erase_block_no);
1683
1684		erase_sector(ns);
1685
1686		NS_MDELAY(erase_delay);
1687
1688		if (erase_block_wear)
1689			update_wear(erase_block_no);
1690
1691		if (erase_error(erase_block_no)) {
1692			NS_WARN("simulating erase failure in erase block %u\n", erase_block_no);
1693			return -1;
1694		}
1695
1696		break;
1697
1698	case ACTION_PRGPAGE:
1699		/*
1700		 * Program page - move internal buffer data to the page.
1701		 */
1702
1703		if (ns->lines.wp) {
1704			NS_WARN("do_state_action: device is write-protected, programm\n");
1705			return -1;
1706		}
1707
1708		num = ns->geom.pgszoob - ns->regs.off - ns->regs.column;
1709		if (num != ns->regs.count) {
1710			NS_ERR("do_state_action: too few bytes were input (%d instead of %d)\n",
1711					ns->regs.count, num);
1712			return -1;
1713		}
1714
1715		if (prog_page(ns, num) == -1)
1716			return -1;
1717
1718		page_no = ns->regs.row;
1719
1720		NS_DBG("do_state_action: copy %d bytes from int buf to (%#x, %#x), raw off = %d\n",
1721			num, ns->regs.row, ns->regs.column, NS_RAW_OFFSET(ns) + ns->regs.off);
1722		NS_LOG("programm page %d\n", ns->regs.row);
1723
1724		NS_UDELAY(programm_delay);
1725		NS_UDELAY(output_cycle * ns->geom.pgsz / 1000 / busdiv);
1726
1727		if (write_error(page_no)) {
1728			NS_WARN("simulating write failure in page %u\n", page_no);
1729			return -1;
1730		}
1731
1732		break;
1733
1734	case ACTION_ZEROOFF:
1735		NS_DBG("do_state_action: set internal offset to 0\n");
1736		ns->regs.off = 0;
1737		break;
1738
1739	case ACTION_HALFOFF:
1740		if (!(ns->options & OPT_PAGE512_8BIT)) {
1741			NS_ERR("do_state_action: BUG! can't skip half of page for non-512"
1742				"byte page size 8x chips\n");
1743			return -1;
1744		}
1745		NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz/2);
1746		ns->regs.off = ns->geom.pgsz/2;
1747		break;
1748
1749	case ACTION_OOBOFF:
1750		NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz);
1751		ns->regs.off = ns->geom.pgsz;
1752		break;
1753
1754	default:
1755		NS_DBG("do_state_action: BUG! unknown action\n");
1756	}
1757
1758	return 0;
1759}
1760
1761/*
1762 * Switch simulator's state.
1763 */
1764static void switch_state(struct nandsim *ns)
1765{
1766	if (ns->op) {
1767		/*
1768		 * The current operation have already been identified.
1769		 * Just follow the states chain.
1770		 */
1771
1772		ns->stateidx += 1;
1773		ns->state = ns->nxstate;
1774		ns->nxstate = ns->op[ns->stateidx + 1];
1775
1776		NS_DBG("switch_state: operation is known, switch to the next state, "
1777			"state: %s, nxstate: %s\n",
1778			get_state_name(ns->state), get_state_name(ns->nxstate));
1779
1780		/* See, whether we need to do some action */
1781		if ((ns->state & ACTION_MASK) && do_state_action(ns, ns->state) < 0) {
1782			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1783			return;
1784		}
1785
1786	} else {
1787		/*
1788		 * We don't yet know which operation we perform.
1789		 * Try to identify it.
1790		 */
1791
1792		/*
1793		 *  The only event causing the switch_state function to
1794		 *  be called with yet unknown operation is new command.
1795		 */
1796		ns->state = get_state_by_command(ns->regs.command);
1797
1798		NS_DBG("switch_state: operation is unknown, try to find it\n");
1799
1800		if (find_operation(ns, 0) != 0)
1801			return;
1802
1803		if ((ns->state & ACTION_MASK) && do_state_action(ns, ns->state) < 0) {
1804			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1805			return;
1806		}
1807	}
1808
1809	/* For 16x devices column means the page offset in words */
1810	if ((ns->nxstate & STATE_ADDR_MASK) && ns->busw == 16) {
1811		NS_DBG("switch_state: double the column number for 16x device\n");
1812		ns->regs.column <<= 1;
1813	}
1814
1815	if (NS_STATE(ns->nxstate) == STATE_READY) {
1816		/*
1817		 * The current state is the last. Return to STATE_READY
1818		 */
1819
1820		u_char status = NS_STATUS_OK(ns);
1821
1822		/* In case of data states, see if all bytes were input/output */
1823		if ((ns->state & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK))
1824			&& ns->regs.count != ns->regs.num) {
1825			NS_WARN("switch_state: not all bytes were processed, %d left\n",
1826					ns->regs.num - ns->regs.count);
1827			status = NS_STATUS_FAILED(ns);
1828		}
1829
1830		NS_DBG("switch_state: operation complete, switch to STATE_READY state\n");
1831
1832		switch_to_ready_state(ns, status);
1833
1834		return;
1835	} else if (ns->nxstate & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK)) {
1836		/*
1837		 * If the next state is data input/output, switch to it now
1838		 */
1839
1840		ns->state      = ns->nxstate;
1841		ns->nxstate    = ns->op[++ns->stateidx + 1];
1842		ns->regs.num   = ns->regs.count = 0;
1843
1844		NS_DBG("switch_state: the next state is data I/O, switch, "
1845			"state: %s, nxstate: %s\n",
1846			get_state_name(ns->state), get_state_name(ns->nxstate));
1847
1848		/*
1849		 * Set the internal register to the count of bytes which
1850		 * are expected to be input or output
1851		 */
1852		switch (NS_STATE(ns->state)) {
1853			case STATE_DATAIN:
1854			case STATE_DATAOUT:
1855				ns->regs.num = ns->geom.pgszoob - ns->regs.off - ns->regs.column;
1856				break;
1857
1858			case STATE_DATAOUT_ID:
1859				ns->regs.num = ns->geom.idbytes;
1860				break;
1861
1862			case STATE_DATAOUT_STATUS:
1863				ns->regs.count = ns->regs.num = 0;
1864				break;
1865
1866			default:
1867				NS_ERR("switch_state: BUG! unknown data state\n");
1868		}
1869
1870	} else if (ns->nxstate & STATE_ADDR_MASK) {
1871		/*
1872		 * If the next state is address input, set the internal
1873		 * register to the number of expected address bytes
1874		 */
1875
1876		ns->regs.count = 0;
1877
1878		switch (NS_STATE(ns->nxstate)) {
1879			case STATE_ADDR_PAGE:
1880				ns->regs.num = ns->geom.pgaddrbytes;
1881
1882				break;
1883			case STATE_ADDR_SEC:
1884				ns->regs.num = ns->geom.secaddrbytes;
1885				break;
1886
1887			case STATE_ADDR_ZERO:
1888				ns->regs.num = 1;
1889				break;
1890
1891			case STATE_ADDR_COLUMN:
1892				/* Column address is always 2 bytes */
1893				ns->regs.num = ns->geom.pgaddrbytes - ns->geom.secaddrbytes;
1894				break;
1895
1896			default:
1897				NS_ERR("switch_state: BUG! unknown address state\n");
1898		}
1899	} else {
1900		/*
1901		 * Just reset internal counters.
1902		 */
1903
1904		ns->regs.num = 0;
1905		ns->regs.count = 0;
1906	}
1907}
1908
1909static u_char ns_nand_read_byte(struct mtd_info *mtd)
1910{
1911	struct nandsim *ns = ((struct nand_chip *)mtd->priv)->priv;
1912	u_char outb = 0x00;
1913
1914	/* Sanity and correctness checks */
1915	if (!ns->lines.ce) {
1916		NS_ERR("read_byte: chip is disabled, return %#x\n", (uint)outb);
1917		return outb;
1918	}
1919	if (ns->lines.ale || ns->lines.cle) {
1920		NS_ERR("read_byte: ALE or CLE pin is high, return %#x\n", (uint)outb);
1921		return outb;
1922	}
1923	if (!(ns->state & STATE_DATAOUT_MASK)) {
1924		NS_WARN("read_byte: unexpected data output cycle, state is %s "
1925			"return %#x\n", get_state_name(ns->state), (uint)outb);
1926		return outb;
1927	}
1928
1929	/* Status register may be read as many times as it is wanted */
1930	if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS) {
1931		NS_DBG("read_byte: return %#x status\n", ns->regs.status);
1932		return ns->regs.status;
1933	}
1934
1935	/* Check if there is any data in the internal buffer which may be read */
1936	if (ns->regs.count == ns->regs.num) {
1937		NS_WARN("read_byte: no more data to output, return %#x\n", (uint)outb);
1938		return outb;
1939	}
1940
1941	switch (NS_STATE(ns->state)) {
1942		case STATE_DATAOUT:
1943			if (ns->busw == 8) {
1944				outb = ns->buf.byte[ns->regs.count];
1945				ns->regs.count += 1;
1946			} else {
1947				outb = (u_char)cpu_to_le16(ns->buf.word[ns->regs.count >> 1]);
1948				ns->regs.count += 2;
1949			}
1950			break;
1951		case STATE_DATAOUT_ID:
1952			NS_DBG("read_byte: read ID byte %d, total = %d\n", ns->regs.count, ns->regs.num);
1953			outb = ns->ids[ns->regs.count];
1954			ns->regs.count += 1;
1955			break;
1956		default:
1957			BUG();
1958	}
1959
1960	if (ns->regs.count == ns->regs.num) {
1961		NS_DBG("read_byte: all bytes were read\n");
1962
1963		if (NS_STATE(ns->nxstate) == STATE_READY)
1964			switch_state(ns);
1965	}
1966
1967	return outb;
1968}
1969
1970static void ns_nand_write_byte(struct mtd_info *mtd, u_char byte)
1971{
1972	struct nandsim *ns = ((struct nand_chip *)mtd->priv)->priv;
1973
1974	/* Sanity and correctness checks */
1975	if (!ns->lines.ce) {
1976		NS_ERR("write_byte: chip is disabled, ignore write\n");
1977		return;
1978	}
1979	if (ns->lines.ale && ns->lines.cle) {
1980		NS_ERR("write_byte: ALE and CLE pins are high simultaneously, ignore write\n");
1981		return;
1982	}
1983
1984	if (ns->lines.cle == 1) {
1985		/*
1986		 * The byte written is a command.
1987		 */
1988
1989		if (byte == NAND_CMD_RESET) {
1990			NS_LOG("reset chip\n");
1991			switch_to_ready_state(ns, NS_STATUS_OK(ns));
1992			return;
1993		}
1994
1995		/* Check that the command byte is correct */
1996		if (check_command(byte)) {
1997			NS_ERR("write_byte: unknown command %#x\n", (uint)byte);
1998			return;
1999		}
2000
2001		if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS
2002			|| NS_STATE(ns->state) == STATE_DATAOUT) {
2003			int row = ns->regs.row;
2004
2005			switch_state(ns);
2006			if (byte == NAND_CMD_RNDOUT)
2007				ns->regs.row = row;
2008		}
2009
2010		/* Check if chip is expecting command */
2011		if (NS_STATE(ns->nxstate) != STATE_UNKNOWN && !(ns->nxstate & STATE_CMD_MASK)) {
2012			/* Do not warn if only 2 id bytes are read */
2013			if (!(ns->regs.command == NAND_CMD_READID &&
2014			    NS_STATE(ns->state) == STATE_DATAOUT_ID && ns->regs.count == 2)) {
2015				/*
2016				 * We are in situation when something else (not command)
2017				 * was expected but command was input. In this case ignore
2018				 * previous command(s)/state(s) and accept the last one.
2019				 */
2020				NS_WARN("write_byte: command (%#x) wasn't expected, expected state is %s, "
2021					"ignore previous states\n", (uint)byte, get_state_name(ns->nxstate));
2022			}
2023			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2024		}
2025
2026		NS_DBG("command byte corresponding to %s state accepted\n",
2027			get_state_name(get_state_by_command(byte)));
2028		ns->regs.command = byte;
2029		switch_state(ns);
2030
2031	} else if (ns->lines.ale == 1) {
2032		/*
2033		 * The byte written is an address.
2034		 */
2035
2036		if (NS_STATE(ns->nxstate) == STATE_UNKNOWN) {
2037
2038			NS_DBG("write_byte: operation isn't known yet, identify it\n");
2039
2040			if (find_operation(ns, 1) < 0)
2041				return;
2042
2043			if ((ns->state & ACTION_MASK) && do_state_action(ns, ns->state) < 0) {
2044				switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2045				return;
2046			}
2047
2048			ns->regs.count = 0;
2049			switch (NS_STATE(ns->nxstate)) {
2050				case STATE_ADDR_PAGE:
2051					ns->regs.num = ns->geom.pgaddrbytes;
2052					break;
2053				case STATE_ADDR_SEC:
2054					ns->regs.num = ns->geom.secaddrbytes;
2055					break;
2056				case STATE_ADDR_ZERO:
2057					ns->regs.num = 1;
2058					break;
2059				default:
2060					BUG();
2061			}
2062		}
2063
2064		/* Check that chip is expecting address */
2065		if (!(ns->nxstate & STATE_ADDR_MASK)) {
2066			NS_ERR("write_byte: address (%#x) isn't expected, expected state is %s, "
2067				"switch to STATE_READY\n", (uint)byte, get_state_name(ns->nxstate));
2068			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2069			return;
2070		}
2071
2072		/* Check if this is expected byte */
2073		if (ns->regs.count == ns->regs.num) {
2074			NS_ERR("write_byte: no more address bytes expected\n");
2075			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2076			return;
2077		}
2078
2079		accept_addr_byte(ns, byte);
2080
2081		ns->regs.count += 1;
2082
2083		NS_DBG("write_byte: address byte %#x was accepted (%d bytes input, %d expected)\n",
2084				(uint)byte, ns->regs.count, ns->regs.num);
2085
2086		if (ns->regs.count == ns->regs.num) {
2087			NS_DBG("address (%#x, %#x) is accepted\n", ns->regs.row, ns->regs.column);
2088			switch_state(ns);
2089		}
2090
2091	} else {
2092		/*
2093		 * The byte written is an input data.
2094		 */
2095
2096		/* Check that chip is expecting data input */
2097		if (!(ns->state & STATE_DATAIN_MASK)) {
2098			NS_ERR("write_byte: data input (%#x) isn't expected, state is %s, "
2099				"switch to %s\n", (uint)byte,
2100				get_state_name(ns->state), get_state_name(STATE_READY));
2101			switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2102			return;
2103		}
2104
2105		/* Check if this is expected byte */
2106		if (ns->regs.count == ns->regs.num) {
2107			NS_WARN("write_byte: %u input bytes has already been accepted, ignore write\n",
2108					ns->regs.num);
2109			return;
2110		}
2111
2112		if (ns->busw == 8) {
2113			ns->buf.byte[ns->regs.count] = byte;
2114			ns->regs.count += 1;
2115		} else {
2116			ns->buf.word[ns->regs.count >> 1] = cpu_to_le16((uint16_t)byte);
2117			ns->regs.count += 2;
2118		}
2119	}
2120
2121	return;
2122}
2123
2124static void ns_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int bitmask)
2125{
2126	struct nandsim *ns = ((struct nand_chip *)mtd->priv)->priv;
2127
2128	ns->lines.cle = bitmask & NAND_CLE ? 1 : 0;
2129	ns->lines.ale = bitmask & NAND_ALE ? 1 : 0;
2130	ns->lines.ce = bitmask & NAND_NCE ? 1 : 0;
2131
2132	if (cmd != NAND_CMD_NONE)
2133		ns_nand_write_byte(mtd, cmd);
2134}
2135
2136static int ns_device_ready(struct mtd_info *mtd)
2137{
2138	NS_DBG("device_ready\n");
2139	return 1;
2140}
2141
2142static uint16_t ns_nand_read_word(struct mtd_info *mtd)
2143{
2144	struct nand_chip *chip = (struct nand_chip *)mtd->priv;
2145
2146	NS_DBG("read_word\n");
2147
2148	return chip->read_byte(mtd) | (chip->read_byte(mtd) << 8);
2149}
2150
2151static void ns_nand_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
2152{
2153	struct nandsim *ns = ((struct nand_chip *)mtd->priv)->priv;
2154
2155	/* Check that chip is expecting data input */
2156	if (!(ns->state & STATE_DATAIN_MASK)) {
2157		NS_ERR("write_buf: data input isn't expected, state is %s, "
2158			"switch to STATE_READY\n", get_state_name(ns->state));
2159		switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2160		return;
2161	}
2162
2163	/* Check if these are expected bytes */
2164	if (ns->regs.count + len > ns->regs.num) {
2165		NS_ERR("write_buf: too many input bytes\n");
2166		switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2167		return;
2168	}
2169
2170	memcpy(ns->buf.byte + ns->regs.count, buf, len);
2171	ns->regs.count += len;
2172
2173	if (ns->regs.count == ns->regs.num) {
2174		NS_DBG("write_buf: %d bytes were written\n", ns->regs.count);
2175	}
2176}
2177
2178static void ns_nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
2179{
2180	struct nandsim *ns = ((struct nand_chip *)mtd->priv)->priv;
2181
2182	/* Sanity and correctness checks */
2183	if (!ns->lines.ce) {
2184		NS_ERR("read_buf: chip is disabled\n");
2185		return;
2186	}
2187	if (ns->lines.ale || ns->lines.cle) {
2188		NS_ERR("read_buf: ALE or CLE pin is high\n");
2189		return;
2190	}
2191	if (!(ns->state & STATE_DATAOUT_MASK)) {
2192		NS_WARN("read_buf: unexpected data output cycle, current state is %s\n",
2193			get_state_name(ns->state));
2194		return;
2195	}
2196
2197	if (NS_STATE(ns->state) != STATE_DATAOUT) {
2198		int i;
2199
2200		for (i = 0; i < len; i++)
2201			buf[i] = ((struct nand_chip *)mtd->priv)->read_byte(mtd);
2202
2203		return;
2204	}
2205
2206	/* Check if these are expected bytes */
2207	if (ns->regs.count + len > ns->regs.num) {
2208		NS_ERR("read_buf: too many bytes to read\n");
2209		switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2210		return;
2211	}
2212
2213	memcpy(buf, ns->buf.byte + ns->regs.count, len);
2214	ns->regs.count += len;
2215
2216	if (ns->regs.count == ns->regs.num) {
2217		if (NS_STATE(ns->nxstate) == STATE_READY)
2218			switch_state(ns);
2219	}
2220
2221	return;
2222}
2223
2224/*
2225 * Module initialization function
2226 */
2227static int __init ns_init_module(void)
2228{
2229	struct nand_chip *chip;
2230	struct nandsim *nand;
2231	int retval = -ENOMEM, i;
2232
2233	if (bus_width != 8 && bus_width != 16) {
2234		NS_ERR("wrong bus width (%d), use only 8 or 16\n", bus_width);
2235		return -EINVAL;
2236	}
2237
2238	/* Allocate and initialize mtd_info, nand_chip and nandsim structures */
2239	nsmtd = kzalloc(sizeof(struct mtd_info) + sizeof(struct nand_chip)
2240				+ sizeof(struct nandsim), GFP_KERNEL);
2241	if (!nsmtd) {
2242		NS_ERR("unable to allocate core structures.\n");
2243		return -ENOMEM;
2244	}
2245	chip        = (struct nand_chip *)(nsmtd + 1);
2246        nsmtd->priv = (void *)chip;
2247	nand        = (struct nandsim *)(chip + 1);
2248	chip->priv  = (void *)nand;
2249
2250	/*
2251	 * Register simulator's callbacks.
2252	 */
2253	chip->cmd_ctrl	 = ns_hwcontrol;
2254	chip->read_byte  = ns_nand_read_byte;
2255	chip->dev_ready  = ns_device_ready;
2256	chip->write_buf  = ns_nand_write_buf;
2257	chip->read_buf   = ns_nand_read_buf;
2258	chip->read_word  = ns_nand_read_word;
2259	chip->ecc.mode   = NAND_ECC_SOFT;
2260	/* The NAND_SKIP_BBTSCAN option is necessary for 'overridesize' */
2261	/* and 'badblocks' parameters to work */
2262	chip->options   |= NAND_SKIP_BBTSCAN;
2263
2264	switch (bbt) {
2265	case 2:
2266		 chip->bbt_options |= NAND_BBT_NO_OOB;
2267	case 1:
2268		 chip->bbt_options |= NAND_BBT_USE_FLASH;
2269	case 0:
2270		break;
2271	default:
2272		NS_ERR("bbt has to be 0..2\n");
2273		retval = -EINVAL;
2274		goto error;
2275	}
2276	/*
2277	 * Perform minimum nandsim structure initialization to handle
2278	 * the initial ID read command correctly
2279	 */
2280	if (id_bytes[6] != 0xFF || id_bytes[7] != 0xFF)
2281		nand->geom.idbytes = 8;
2282	else if (id_bytes[4] != 0xFF || id_bytes[5] != 0xFF)
2283		nand->geom.idbytes = 6;
2284	else if (id_bytes[2] != 0xFF || id_bytes[3] != 0xFF)
2285		nand->geom.idbytes = 4;
2286	else
2287		nand->geom.idbytes = 2;
2288	nand->regs.status = NS_STATUS_OK(nand);
2289	nand->nxstate = STATE_UNKNOWN;
2290	nand->options |= OPT_PAGE512; /* temporary value */
2291	memcpy(nand->ids, id_bytes, sizeof(nand->ids));
2292	if (bus_width == 16) {
2293		nand->busw = 16;
2294		chip->options |= NAND_BUSWIDTH_16;
2295	}
2296
2297	nsmtd->owner = THIS_MODULE;
2298
2299	if ((retval = parse_weakblocks()) != 0)
2300		goto error;
2301
2302	if ((retval = parse_weakpages()) != 0)
2303		goto error;
2304
2305	if ((retval = parse_gravepages()) != 0)
2306		goto error;
2307
2308	retval = nand_scan_ident(nsmtd, 1, NULL);
2309	if (retval) {
2310		NS_ERR("cannot scan NAND Simulator device\n");
2311		if (retval > 0)
2312			retval = -ENXIO;
2313		goto error;
2314	}
2315
2316	if (bch) {
2317		unsigned int eccsteps, eccbytes;
2318		if (!mtd_nand_has_bch()) {
2319			NS_ERR("BCH ECC support is disabled\n");
2320			retval = -EINVAL;
2321			goto error;
2322		}
2323		/* use 512-byte ecc blocks */
2324		eccsteps = nsmtd->writesize/512;
2325		eccbytes = (bch*13+7)/8;
2326		/* do not bother supporting small page devices */
2327		if ((nsmtd->oobsize < 64) || !eccsteps) {
2328			NS_ERR("bch not available on small page devices\n");
2329			retval = -EINVAL;
2330			goto error;
2331		}
2332		if ((eccbytes*eccsteps+2) > nsmtd->oobsize) {
2333			NS_ERR("invalid bch value %u\n", bch);
2334			retval = -EINVAL;
2335			goto error;
2336		}
2337		chip->ecc.mode = NAND_ECC_SOFT_BCH;
2338		chip->ecc.size = 512;
2339		chip->ecc.strength = bch;
2340		chip->ecc.bytes = eccbytes;
2341		NS_INFO("using %u-bit/%u bytes BCH ECC\n", bch, chip->ecc.size);
2342	}
2343
2344	retval = nand_scan_tail(nsmtd);
2345	if (retval) {
2346		NS_ERR("can't register NAND Simulator\n");
2347		if (retval > 0)
2348			retval = -ENXIO;
2349		goto error;
2350	}
2351
2352	if (overridesize) {
2353		uint64_t new_size = (uint64_t)nsmtd->erasesize << overridesize;
2354		if (new_size >> overridesize != nsmtd->erasesize) {
2355			NS_ERR("overridesize is too big\n");
2356			retval = -EINVAL;
2357			goto err_exit;
2358		}
2359		/* N.B. This relies on nand_scan not doing anything with the size before we change it */
2360		nsmtd->size = new_size;
2361		chip->chipsize = new_size;
2362		chip->chip_shift = ffs(nsmtd->erasesize) + overridesize - 1;
2363		chip->pagemask = (chip->chipsize >> chip->page_shift) - 1;
2364	}
2365
2366	if ((retval = setup_wear_reporting(nsmtd)) != 0)
2367		goto err_exit;
2368
2369	if ((retval = nandsim_debugfs_create(nand)) != 0)
2370		goto err_exit;
2371
2372	if ((retval = init_nandsim(nsmtd)) != 0)
2373		goto err_exit;
2374
2375	if ((retval = chip->scan_bbt(nsmtd)) != 0)
2376		goto err_exit;
2377
2378	if ((retval = parse_badblocks(nand, nsmtd)) != 0)
2379		goto err_exit;
2380
2381	/* Register NAND partitions */
2382	retval = mtd_device_register(nsmtd, &nand->partitions[0],
2383				     nand->nbparts);
2384	if (retval != 0)
2385		goto err_exit;
2386
2387        return 0;
2388
2389err_exit:
2390	free_nandsim(nand);
2391	nand_release(nsmtd);
2392	for (i = 0;i < ARRAY_SIZE(nand->partitions); ++i)
2393		kfree(nand->partitions[i].name);
2394error:
2395	kfree(nsmtd);
2396	free_lists();
2397
2398	return retval;
2399}
2400
2401module_init(ns_init_module);
2402
2403/*
2404 * Module clean-up function
2405 */
2406static void __exit ns_cleanup_module(void)
2407{
2408	struct nandsim *ns = ((struct nand_chip *)nsmtd->priv)->priv;
2409	int i;
2410
2411	nandsim_debugfs_remove(ns);
2412	free_nandsim(ns);    /* Free nandsim private resources */
2413	nand_release(nsmtd); /* Unregister driver */
2414	for (i = 0;i < ARRAY_SIZE(ns->partitions); ++i)
2415		kfree(ns->partitions[i].name);
2416	kfree(nsmtd);        /* Free other structures */
2417	free_lists();
2418}
2419
2420module_exit(ns_cleanup_module);
2421
2422MODULE_LICENSE ("GPL");
2423MODULE_AUTHOR ("Artem B. Bityuckiy");
2424MODULE_DESCRIPTION ("The NAND flash simulator");
2425