1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * NAND flash simulator.
4 *
5 * Author: Artem B. Bityuckiy <dedekind@oktetlabs.ru>, <dedekind@infradead.org>
6 *
7 * Copyright (C) 2004 Nokia Corporation
8 *
9 * Note: NS means "NAND Simulator".
10 * Note: Input means input TO flash chip, output means output FROM chip.
11 */
12
13#define pr_fmt(fmt)  "[nandsim]" fmt
14
15#include <linux/init.h>
16#include <linux/types.h>
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/vmalloc.h>
20#include <linux/math64.h>
21#include <linux/slab.h>
22#include <linux/errno.h>
23#include <linux/string.h>
24#include <linux/mtd/mtd.h>
25#include <linux/mtd/rawnand.h>
26#include <linux/mtd/partitions.h>
27#include <linux/delay.h>
28#include <linux/list.h>
29#include <linux/random.h>
30#include <linux/sched.h>
31#include <linux/sched/mm.h>
32#include <linux/fs.h>
33#include <linux/pagemap.h>
34#include <linux/seq_file.h>
35#include <linux/debugfs.h>
36
37/* Default simulator parameters values */
38#if !defined(CONFIG_NANDSIM_FIRST_ID_BYTE)  || \
39    !defined(CONFIG_NANDSIM_SECOND_ID_BYTE) || \
40    !defined(CONFIG_NANDSIM_THIRD_ID_BYTE)  || \
41    !defined(CONFIG_NANDSIM_FOURTH_ID_BYTE)
42#define CONFIG_NANDSIM_FIRST_ID_BYTE  0x98
43#define CONFIG_NANDSIM_SECOND_ID_BYTE 0x39
44#define CONFIG_NANDSIM_THIRD_ID_BYTE  0xFF /* No byte */
45#define CONFIG_NANDSIM_FOURTH_ID_BYTE 0xFF /* No byte */
46#endif
47
48#ifndef CONFIG_NANDSIM_ACCESS_DELAY
49#define CONFIG_NANDSIM_ACCESS_DELAY 25
50#endif
51#ifndef CONFIG_NANDSIM_PROGRAMM_DELAY
52#define CONFIG_NANDSIM_PROGRAMM_DELAY 200
53#endif
54#ifndef CONFIG_NANDSIM_ERASE_DELAY
55#define CONFIG_NANDSIM_ERASE_DELAY 2
56#endif
57#ifndef CONFIG_NANDSIM_OUTPUT_CYCLE
58#define CONFIG_NANDSIM_OUTPUT_CYCLE 40
59#endif
60#ifndef CONFIG_NANDSIM_INPUT_CYCLE
61#define CONFIG_NANDSIM_INPUT_CYCLE  50
62#endif
63#ifndef CONFIG_NANDSIM_BUS_WIDTH
64#define CONFIG_NANDSIM_BUS_WIDTH  8
65#endif
66#ifndef CONFIG_NANDSIM_DO_DELAYS
67#define CONFIG_NANDSIM_DO_DELAYS  0
68#endif
69#ifndef CONFIG_NANDSIM_LOG
70#define CONFIG_NANDSIM_LOG        0
71#endif
72#ifndef CONFIG_NANDSIM_DBG
73#define CONFIG_NANDSIM_DBG        0
74#endif
75#ifndef CONFIG_NANDSIM_MAX_PARTS
76#define CONFIG_NANDSIM_MAX_PARTS  32
77#endif
78
79static uint access_delay   = CONFIG_NANDSIM_ACCESS_DELAY;
80static uint programm_delay = CONFIG_NANDSIM_PROGRAMM_DELAY;
81static uint erase_delay    = CONFIG_NANDSIM_ERASE_DELAY;
82static uint output_cycle   = CONFIG_NANDSIM_OUTPUT_CYCLE;
83static uint input_cycle    = CONFIG_NANDSIM_INPUT_CYCLE;
84static uint bus_width      = CONFIG_NANDSIM_BUS_WIDTH;
85static uint do_delays      = CONFIG_NANDSIM_DO_DELAYS;
86static uint log            = CONFIG_NANDSIM_LOG;
87static uint dbg            = CONFIG_NANDSIM_DBG;
88static unsigned long parts[CONFIG_NANDSIM_MAX_PARTS];
89static unsigned int parts_num;
90static char *badblocks = NULL;
91static char *weakblocks = NULL;
92static char *weakpages = NULL;
93static unsigned int bitflips = 0;
94static char *gravepages = NULL;
95static unsigned int overridesize = 0;
96static char *cache_file = NULL;
97static unsigned int bbt;
98static unsigned int bch;
99static u_char id_bytes[8] = {
100	[0] = CONFIG_NANDSIM_FIRST_ID_BYTE,
101	[1] = CONFIG_NANDSIM_SECOND_ID_BYTE,
102	[2] = CONFIG_NANDSIM_THIRD_ID_BYTE,
103	[3] = CONFIG_NANDSIM_FOURTH_ID_BYTE,
104	[4 ... 7] = 0xFF,
105};
106
107module_param_array(id_bytes, byte, NULL, 0400);
108module_param_named(first_id_byte, id_bytes[0], byte, 0400);
109module_param_named(second_id_byte, id_bytes[1], byte, 0400);
110module_param_named(third_id_byte, id_bytes[2], byte, 0400);
111module_param_named(fourth_id_byte, id_bytes[3], byte, 0400);
112module_param(access_delay,   uint, 0400);
113module_param(programm_delay, uint, 0400);
114module_param(erase_delay,    uint, 0400);
115module_param(output_cycle,   uint, 0400);
116module_param(input_cycle,    uint, 0400);
117module_param(bus_width,      uint, 0400);
118module_param(do_delays,      uint, 0400);
119module_param(log,            uint, 0400);
120module_param(dbg,            uint, 0400);
121module_param_array(parts, ulong, &parts_num, 0400);
122module_param(badblocks,      charp, 0400);
123module_param(weakblocks,     charp, 0400);
124module_param(weakpages,      charp, 0400);
125module_param(bitflips,       uint, 0400);
126module_param(gravepages,     charp, 0400);
127module_param(overridesize,   uint, 0400);
128module_param(cache_file,     charp, 0400);
129module_param(bbt,	     uint, 0400);
130module_param(bch,	     uint, 0400);
131
132MODULE_PARM_DESC(id_bytes,       "The ID bytes returned by NAND Flash 'read ID' command");
133MODULE_PARM_DESC(first_id_byte,  "The first byte returned by NAND Flash 'read ID' command (manufacturer ID) (obsolete)");
134MODULE_PARM_DESC(second_id_byte, "The second byte returned by NAND Flash 'read ID' command (chip ID) (obsolete)");
135MODULE_PARM_DESC(third_id_byte,  "The third byte returned by NAND Flash 'read ID' command (obsolete)");
136MODULE_PARM_DESC(fourth_id_byte, "The fourth byte returned by NAND Flash 'read ID' command (obsolete)");
137MODULE_PARM_DESC(access_delay,   "Initial page access delay (microseconds)");
138MODULE_PARM_DESC(programm_delay, "Page programm delay (microseconds");
139MODULE_PARM_DESC(erase_delay,    "Sector erase delay (milliseconds)");
140MODULE_PARM_DESC(output_cycle,   "Word output (from flash) time (nanoseconds)");
141MODULE_PARM_DESC(input_cycle,    "Word input (to flash) time (nanoseconds)");
142MODULE_PARM_DESC(bus_width,      "Chip's bus width (8- or 16-bit)");
143MODULE_PARM_DESC(do_delays,      "Simulate NAND delays using busy-waits if not zero");
144MODULE_PARM_DESC(log,            "Perform logging if not zero");
145MODULE_PARM_DESC(dbg,            "Output debug information if not zero");
146MODULE_PARM_DESC(parts,          "Partition sizes (in erase blocks) separated by commas");
147/* Page and erase block positions for the following parameters are independent of any partitions */
148MODULE_PARM_DESC(badblocks,      "Erase blocks that are initially marked bad, separated by commas");
149MODULE_PARM_DESC(weakblocks,     "Weak erase blocks [: remaining erase cycles (defaults to 3)]"
150				 " separated by commas e.g. 113:2 means eb 113"
151				 " can be erased only twice before failing");
152MODULE_PARM_DESC(weakpages,      "Weak pages [: maximum writes (defaults to 3)]"
153				 " separated by commas e.g. 1401:2 means page 1401"
154				 " can be written only twice before failing");
155MODULE_PARM_DESC(bitflips,       "Maximum number of random bit flips per page (zero by default)");
156MODULE_PARM_DESC(gravepages,     "Pages that lose data [: maximum reads (defaults to 3)]"
157				 " separated by commas e.g. 1401:2 means page 1401"
158				 " can be read only twice before failing");
159MODULE_PARM_DESC(overridesize,   "Specifies the NAND Flash size overriding the ID bytes. "
160				 "The size is specified in erase blocks and as the exponent of a power of two"
161				 " e.g. 5 means a size of 32 erase blocks");
162MODULE_PARM_DESC(cache_file,     "File to use to cache nand pages instead of memory");
163MODULE_PARM_DESC(bbt,		 "0 OOB, 1 BBT with marker in OOB, 2 BBT with marker in data area");
164MODULE_PARM_DESC(bch,		 "Enable BCH ecc and set how many bits should "
165				 "be correctable in 512-byte blocks");
166
167/* The largest possible page size */
168#define NS_LARGEST_PAGE_SIZE	4096
169
170/* Simulator's output macros (logging, debugging, warning, error) */
171#define NS_LOG(args...) \
172	do { if (log) pr_debug(" log: " args); } while(0)
173#define NS_DBG(args...) \
174	do { if (dbg) pr_debug(" debug: " args); } while(0)
175#define NS_WARN(args...) \
176	do { pr_warn(" warning: " args); } while(0)
177#define NS_ERR(args...) \
178	do { pr_err(" error: " args); } while(0)
179#define NS_INFO(args...) \
180	do { pr_info(" " args); } while(0)
181
182/* Busy-wait delay macros (microseconds, milliseconds) */
183#define NS_UDELAY(us) \
184        do { if (do_delays) udelay(us); } while(0)
185#define NS_MDELAY(us) \
186        do { if (do_delays) mdelay(us); } while(0)
187
188/* Is the nandsim structure initialized ? */
189#define NS_IS_INITIALIZED(ns) ((ns)->geom.totsz != 0)
190
191/* Good operation completion status */
192#define NS_STATUS_OK(ns) (NAND_STATUS_READY | (NAND_STATUS_WP * ((ns)->lines.wp == 0)))
193
194/* Operation failed completion status */
195#define NS_STATUS_FAILED(ns) (NAND_STATUS_FAIL | NS_STATUS_OK(ns))
196
197/* Calculate the page offset in flash RAM image by (row, column) address */
198#define NS_RAW_OFFSET(ns) \
199	(((ns)->regs.row * (ns)->geom.pgszoob) + (ns)->regs.column)
200
201/* Calculate the OOB offset in flash RAM image by (row, column) address */
202#define NS_RAW_OFFSET_OOB(ns) (NS_RAW_OFFSET(ns) + ns->geom.pgsz)
203
204/* Calculate the byte shift in the next page to access */
205#define NS_PAGE_BYTE_SHIFT(ns) ((ns)->regs.column + (ns)->regs.off)
206
207/* After a command is input, the simulator goes to one of the following states */
208#define STATE_CMD_READ0        0x00000001 /* read data from the beginning of page */
209#define STATE_CMD_READ1        0x00000002 /* read data from the second half of page */
210#define STATE_CMD_READSTART    0x00000003 /* read data second command (large page devices) */
211#define STATE_CMD_PAGEPROG     0x00000004 /* start page program */
212#define STATE_CMD_READOOB      0x00000005 /* read OOB area */
213#define STATE_CMD_ERASE1       0x00000006 /* sector erase first command */
214#define STATE_CMD_STATUS       0x00000007 /* read status */
215#define STATE_CMD_SEQIN        0x00000009 /* sequential data input */
216#define STATE_CMD_READID       0x0000000A /* read ID */
217#define STATE_CMD_ERASE2       0x0000000B /* sector erase second command */
218#define STATE_CMD_RESET        0x0000000C /* reset */
219#define STATE_CMD_RNDOUT       0x0000000D /* random output command */
220#define STATE_CMD_RNDOUTSTART  0x0000000E /* random output start command */
221#define STATE_CMD_MASK         0x0000000F /* command states mask */
222
223/* After an address is input, the simulator goes to one of these states */
224#define STATE_ADDR_PAGE        0x00000010 /* full (row, column) address is accepted */
225#define STATE_ADDR_SEC         0x00000020 /* sector address was accepted */
226#define STATE_ADDR_COLUMN      0x00000030 /* column address was accepted */
227#define STATE_ADDR_ZERO        0x00000040 /* one byte zero address was accepted */
228#define STATE_ADDR_MASK        0x00000070 /* address states mask */
229
230/* During data input/output the simulator is in these states */
231#define STATE_DATAIN           0x00000100 /* waiting for data input */
232#define STATE_DATAIN_MASK      0x00000100 /* data input states mask */
233
234#define STATE_DATAOUT          0x00001000 /* waiting for page data output */
235#define STATE_DATAOUT_ID       0x00002000 /* waiting for ID bytes output */
236#define STATE_DATAOUT_STATUS   0x00003000 /* waiting for status output */
237#define STATE_DATAOUT_MASK     0x00007000 /* data output states mask */
238
239/* Previous operation is done, ready to accept new requests */
240#define STATE_READY            0x00000000
241
242/* This state is used to mark that the next state isn't known yet */
243#define STATE_UNKNOWN          0x10000000
244
245/* Simulator's actions bit masks */
246#define ACTION_CPY       0x00100000 /* copy page/OOB to the internal buffer */
247#define ACTION_PRGPAGE   0x00200000 /* program the internal buffer to flash */
248#define ACTION_SECERASE  0x00300000 /* erase sector */
249#define ACTION_ZEROOFF   0x00400000 /* don't add any offset to address */
250#define ACTION_HALFOFF   0x00500000 /* add to address half of page */
251#define ACTION_OOBOFF    0x00600000 /* add to address OOB offset */
252#define ACTION_MASK      0x00700000 /* action mask */
253
254#define NS_OPER_NUM      13 /* Number of operations supported by the simulator */
255#define NS_OPER_STATES   6  /* Maximum number of states in operation */
256
257#define OPT_ANY          0xFFFFFFFF /* any chip supports this operation */
258#define OPT_PAGE512      0x00000002 /* 512-byte  page chips */
259#define OPT_PAGE2048     0x00000008 /* 2048-byte page chips */
260#define OPT_PAGE512_8BIT 0x00000040 /* 512-byte page chips with 8-bit bus width */
261#define OPT_PAGE4096     0x00000080 /* 4096-byte page chips */
262#define OPT_LARGEPAGE    (OPT_PAGE2048 | OPT_PAGE4096) /* 2048 & 4096-byte page chips */
263#define OPT_SMALLPAGE    (OPT_PAGE512) /* 512-byte page chips */
264
265/* Remove action bits from state */
266#define NS_STATE(x) ((x) & ~ACTION_MASK)
267
268/*
269 * Maximum previous states which need to be saved. Currently saving is
270 * only needed for page program operation with preceded read command
271 * (which is only valid for 512-byte pages).
272 */
273#define NS_MAX_PREVSTATES 1
274
275/* Maximum page cache pages needed to read or write a NAND page to the cache_file */
276#define NS_MAX_HELD_PAGES 16
277
278/*
279 * A union to represent flash memory contents and flash buffer.
280 */
281union ns_mem {
282	u_char *byte;    /* for byte access */
283	uint16_t *word;  /* for 16-bit word access */
284};
285
286/*
287 * The structure which describes all the internal simulator data.
288 */
289struct nandsim {
290	struct nand_chip chip;
291	struct nand_controller base;
292	struct mtd_partition partitions[CONFIG_NANDSIM_MAX_PARTS];
293	unsigned int nbparts;
294
295	uint busw;              /* flash chip bus width (8 or 16) */
296	u_char ids[8];          /* chip's ID bytes */
297	uint32_t options;       /* chip's characteristic bits */
298	uint32_t state;         /* current chip state */
299	uint32_t nxstate;       /* next expected state */
300
301	uint32_t *op;           /* current operation, NULL operations isn't known yet  */
302	uint32_t pstates[NS_MAX_PREVSTATES]; /* previous states */
303	uint16_t npstates;      /* number of previous states saved */
304	uint16_t stateidx;      /* current state index */
305
306	/* The simulated NAND flash pages array */
307	union ns_mem *pages;
308
309	/* Slab allocator for nand pages */
310	struct kmem_cache *nand_pages_slab;
311
312	/* Internal buffer of page + OOB size bytes */
313	union ns_mem buf;
314
315	/* NAND flash "geometry" */
316	struct {
317		uint64_t totsz;     /* total flash size, bytes */
318		uint32_t secsz;     /* flash sector (erase block) size, bytes */
319		uint pgsz;          /* NAND flash page size, bytes */
320		uint oobsz;         /* page OOB area size, bytes */
321		uint64_t totszoob;  /* total flash size including OOB, bytes */
322		uint pgszoob;       /* page size including OOB , bytes*/
323		uint secszoob;      /* sector size including OOB, bytes */
324		uint pgnum;         /* total number of pages */
325		uint pgsec;         /* number of pages per sector */
326		uint secshift;      /* bits number in sector size */
327		uint pgshift;       /* bits number in page size */
328		uint pgaddrbytes;   /* bytes per page address */
329		uint secaddrbytes;  /* bytes per sector address */
330		uint idbytes;       /* the number ID bytes that this chip outputs */
331	} geom;
332
333	/* NAND flash internal registers */
334	struct {
335		unsigned command; /* the command register */
336		u_char   status;  /* the status register */
337		uint     row;     /* the page number */
338		uint     column;  /* the offset within page */
339		uint     count;   /* internal counter */
340		uint     num;     /* number of bytes which must be processed */
341		uint     off;     /* fixed page offset */
342	} regs;
343
344	/* NAND flash lines state */
345        struct {
346                int ce;  /* chip Enable */
347                int cle; /* command Latch Enable */
348                int ale; /* address Latch Enable */
349                int wp;  /* write Protect */
350        } lines;
351
352	/* Fields needed when using a cache file */
353	struct file *cfile; /* Open file */
354	unsigned long *pages_written; /* Which pages have been written */
355	void *file_buf;
356	struct page *held_pages[NS_MAX_HELD_PAGES];
357	int held_cnt;
358
359	/* debugfs entry */
360	struct dentry *dent;
361};
362
363/*
364 * Operations array. To perform any operation the simulator must pass
365 * through the correspondent states chain.
366 */
367static struct nandsim_operations {
368	uint32_t reqopts;  /* options which are required to perform the operation */
369	uint32_t states[NS_OPER_STATES]; /* operation's states */
370} ops[NS_OPER_NUM] = {
371	/* Read page + OOB from the beginning */
372	{OPT_SMALLPAGE, {STATE_CMD_READ0 | ACTION_ZEROOFF, STATE_ADDR_PAGE | ACTION_CPY,
373			STATE_DATAOUT, STATE_READY}},
374	/* Read page + OOB from the second half */
375	{OPT_PAGE512_8BIT, {STATE_CMD_READ1 | ACTION_HALFOFF, STATE_ADDR_PAGE | ACTION_CPY,
376			STATE_DATAOUT, STATE_READY}},
377	/* Read OOB */
378	{OPT_SMALLPAGE, {STATE_CMD_READOOB | ACTION_OOBOFF, STATE_ADDR_PAGE | ACTION_CPY,
379			STATE_DATAOUT, STATE_READY}},
380	/* Program page starting from the beginning */
381	{OPT_ANY, {STATE_CMD_SEQIN, STATE_ADDR_PAGE, STATE_DATAIN,
382			STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
383	/* Program page starting from the beginning */
384	{OPT_SMALLPAGE, {STATE_CMD_READ0, STATE_CMD_SEQIN | ACTION_ZEROOFF, STATE_ADDR_PAGE,
385			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
386	/* Program page starting from the second half */
387	{OPT_PAGE512, {STATE_CMD_READ1, STATE_CMD_SEQIN | ACTION_HALFOFF, STATE_ADDR_PAGE,
388			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
389	/* Program OOB */
390	{OPT_SMALLPAGE, {STATE_CMD_READOOB, STATE_CMD_SEQIN | ACTION_OOBOFF, STATE_ADDR_PAGE,
391			      STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
392	/* Erase sector */
393	{OPT_ANY, {STATE_CMD_ERASE1, STATE_ADDR_SEC, STATE_CMD_ERASE2 | ACTION_SECERASE, STATE_READY}},
394	/* Read status */
395	{OPT_ANY, {STATE_CMD_STATUS, STATE_DATAOUT_STATUS, STATE_READY}},
396	/* Read ID */
397	{OPT_ANY, {STATE_CMD_READID, STATE_ADDR_ZERO, STATE_DATAOUT_ID, STATE_READY}},
398	/* Large page devices read page */
399	{OPT_LARGEPAGE, {STATE_CMD_READ0, STATE_ADDR_PAGE, STATE_CMD_READSTART | ACTION_CPY,
400			       STATE_DATAOUT, STATE_READY}},
401	/* Large page devices random page read */
402	{OPT_LARGEPAGE, {STATE_CMD_RNDOUT, STATE_ADDR_COLUMN, STATE_CMD_RNDOUTSTART | ACTION_CPY,
403			       STATE_DATAOUT, STATE_READY}},
404};
405
406struct weak_block {
407	struct list_head list;
408	unsigned int erase_block_no;
409	unsigned int max_erases;
410	unsigned int erases_done;
411};
412
413static LIST_HEAD(weak_blocks);
414
415struct weak_page {
416	struct list_head list;
417	unsigned int page_no;
418	unsigned int max_writes;
419	unsigned int writes_done;
420};
421
422static LIST_HEAD(weak_pages);
423
424struct grave_page {
425	struct list_head list;
426	unsigned int page_no;
427	unsigned int max_reads;
428	unsigned int reads_done;
429};
430
431static LIST_HEAD(grave_pages);
432
433static unsigned long *erase_block_wear = NULL;
434static unsigned int wear_eb_count = 0;
435static unsigned long total_wear = 0;
436
437/* MTD structure for NAND controller */
438static struct mtd_info *nsmtd;
439
440static int ns_show(struct seq_file *m, void *private)
441{
442	unsigned long wmin = -1, wmax = 0, avg;
443	unsigned long deciles[10], decile_max[10], tot = 0;
444	unsigned int i;
445
446	/* Calc wear stats */
447	for (i = 0; i < wear_eb_count; ++i) {
448		unsigned long wear = erase_block_wear[i];
449		if (wear < wmin)
450			wmin = wear;
451		if (wear > wmax)
452			wmax = wear;
453		tot += wear;
454	}
455
456	for (i = 0; i < 9; ++i) {
457		deciles[i] = 0;
458		decile_max[i] = (wmax * (i + 1) + 5) / 10;
459	}
460	deciles[9] = 0;
461	decile_max[9] = wmax;
462	for (i = 0; i < wear_eb_count; ++i) {
463		int d;
464		unsigned long wear = erase_block_wear[i];
465		for (d = 0; d < 10; ++d)
466			if (wear <= decile_max[d]) {
467				deciles[d] += 1;
468				break;
469			}
470	}
471	avg = tot / wear_eb_count;
472
473	/* Output wear report */
474	seq_printf(m, "Total numbers of erases:  %lu\n", tot);
475	seq_printf(m, "Number of erase blocks:   %u\n", wear_eb_count);
476	seq_printf(m, "Average number of erases: %lu\n", avg);
477	seq_printf(m, "Maximum number of erases: %lu\n", wmax);
478	seq_printf(m, "Minimum number of erases: %lu\n", wmin);
479	for (i = 0; i < 10; ++i) {
480		unsigned long from = (i ? decile_max[i - 1] + 1 : 0);
481		if (from > decile_max[i])
482			continue;
483		seq_printf(m, "Number of ebs with erase counts from %lu to %lu : %lu\n",
484			from,
485			decile_max[i],
486			deciles[i]);
487	}
488
489	return 0;
490}
491DEFINE_SHOW_ATTRIBUTE(ns);
492
493/**
494 * ns_debugfs_create - initialize debugfs
495 * @ns: nandsim device description object
496 *
497 * This function creates all debugfs files for UBI device @ubi. Returns zero in
498 * case of success and a negative error code in case of failure.
499 */
500static int ns_debugfs_create(struct nandsim *ns)
501{
502	struct dentry *root = nsmtd->dbg.dfs_dir;
503
504	/*
505	 * Just skip debugfs initialization when the debugfs directory is
506	 * missing.
507	 */
508	if (IS_ERR_OR_NULL(root)) {
509		if (IS_ENABLED(CONFIG_DEBUG_FS) &&
510		    !IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER))
511			NS_WARN("CONFIG_MTD_PARTITIONED_MASTER must be enabled to expose debugfs stuff\n");
512		return 0;
513	}
514
515	ns->dent = debugfs_create_file("nandsim_wear_report", 0400, root, ns,
516				       &ns_fops);
517	if (IS_ERR_OR_NULL(ns->dent)) {
518		NS_ERR("cannot create \"nandsim_wear_report\" debugfs entry\n");
519		return -1;
520	}
521
522	return 0;
523}
524
525static void ns_debugfs_remove(struct nandsim *ns)
526{
527	debugfs_remove_recursive(ns->dent);
528}
529
530/*
531 * Allocate array of page pointers, create slab allocation for an array
532 * and initialize the array by NULL pointers.
533 *
534 * RETURNS: 0 if success, -ENOMEM if memory alloc fails.
535 */
536static int __init ns_alloc_device(struct nandsim *ns)
537{
538	struct file *cfile;
539	int i, err;
540
541	if (cache_file) {
542		cfile = filp_open(cache_file, O_CREAT | O_RDWR | O_LARGEFILE, 0600);
543		if (IS_ERR(cfile))
544			return PTR_ERR(cfile);
545		if (!(cfile->f_mode & FMODE_CAN_READ)) {
546			NS_ERR("alloc_device: cache file not readable\n");
547			err = -EINVAL;
548			goto err_close_filp;
549		}
550		if (!(cfile->f_mode & FMODE_CAN_WRITE)) {
551			NS_ERR("alloc_device: cache file not writeable\n");
552			err = -EINVAL;
553			goto err_close_filp;
554		}
555		ns->pages_written =
556			vzalloc(array_size(sizeof(unsigned long),
557					   BITS_TO_LONGS(ns->geom.pgnum)));
558		if (!ns->pages_written) {
559			NS_ERR("alloc_device: unable to allocate pages written array\n");
560			err = -ENOMEM;
561			goto err_close_filp;
562		}
563		ns->file_buf = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
564		if (!ns->file_buf) {
565			NS_ERR("alloc_device: unable to allocate file buf\n");
566			err = -ENOMEM;
567			goto err_free_pw;
568		}
569		ns->cfile = cfile;
570
571		return 0;
572
573err_free_pw:
574		vfree(ns->pages_written);
575err_close_filp:
576		filp_close(cfile, NULL);
577
578		return err;
579	}
580
581	ns->pages = vmalloc(array_size(sizeof(union ns_mem), ns->geom.pgnum));
582	if (!ns->pages) {
583		NS_ERR("alloc_device: unable to allocate page array\n");
584		return -ENOMEM;
585	}
586	for (i = 0; i < ns->geom.pgnum; i++) {
587		ns->pages[i].byte = NULL;
588	}
589	ns->nand_pages_slab = kmem_cache_create("nandsim",
590						ns->geom.pgszoob, 0, 0, NULL);
591	if (!ns->nand_pages_slab) {
592		NS_ERR("cache_create: unable to create kmem_cache\n");
593		err = -ENOMEM;
594		goto err_free_pg;
595	}
596
597	return 0;
598
599err_free_pg:
600	vfree(ns->pages);
601
602	return err;
603}
604
605/*
606 * Free any allocated pages, and free the array of page pointers.
607 */
608static void ns_free_device(struct nandsim *ns)
609{
610	int i;
611
612	if (ns->cfile) {
613		kfree(ns->file_buf);
614		vfree(ns->pages_written);
615		filp_close(ns->cfile, NULL);
616		return;
617	}
618
619	if (ns->pages) {
620		for (i = 0; i < ns->geom.pgnum; i++) {
621			if (ns->pages[i].byte)
622				kmem_cache_free(ns->nand_pages_slab,
623						ns->pages[i].byte);
624		}
625		kmem_cache_destroy(ns->nand_pages_slab);
626		vfree(ns->pages);
627	}
628}
629
630static char __init *ns_get_partition_name(int i)
631{
632	return kasprintf(GFP_KERNEL, "NAND simulator partition %d", i);
633}
634
635/*
636 * Initialize the nandsim structure.
637 *
638 * RETURNS: 0 if success, -ERRNO if failure.
639 */
640static int __init ns_init(struct mtd_info *mtd)
641{
642	struct nand_chip *chip = mtd_to_nand(mtd);
643	struct nandsim   *ns   = nand_get_controller_data(chip);
644	int i, ret = 0;
645	uint64_t remains;
646	uint64_t next_offset;
647
648	if (NS_IS_INITIALIZED(ns)) {
649		NS_ERR("init_nandsim: nandsim is already initialized\n");
650		return -EIO;
651	}
652
653	/* Initialize the NAND flash parameters */
654	ns->busw = chip->options & NAND_BUSWIDTH_16 ? 16 : 8;
655	ns->geom.totsz    = mtd->size;
656	ns->geom.pgsz     = mtd->writesize;
657	ns->geom.oobsz    = mtd->oobsize;
658	ns->geom.secsz    = mtd->erasesize;
659	ns->geom.pgszoob  = ns->geom.pgsz + ns->geom.oobsz;
660	ns->geom.pgnum    = div_u64(ns->geom.totsz, ns->geom.pgsz);
661	ns->geom.totszoob = ns->geom.totsz + (uint64_t)ns->geom.pgnum * ns->geom.oobsz;
662	ns->geom.secshift = ffs(ns->geom.secsz) - 1;
663	ns->geom.pgshift  = chip->page_shift;
664	ns->geom.pgsec    = ns->geom.secsz / ns->geom.pgsz;
665	ns->geom.secszoob = ns->geom.secsz + ns->geom.oobsz * ns->geom.pgsec;
666	ns->options = 0;
667
668	if (ns->geom.pgsz == 512) {
669		ns->options |= OPT_PAGE512;
670		if (ns->busw == 8)
671			ns->options |= OPT_PAGE512_8BIT;
672	} else if (ns->geom.pgsz == 2048) {
673		ns->options |= OPT_PAGE2048;
674	} else if (ns->geom.pgsz == 4096) {
675		ns->options |= OPT_PAGE4096;
676	} else {
677		NS_ERR("init_nandsim: unknown page size %u\n", ns->geom.pgsz);
678		return -EIO;
679	}
680
681	if (ns->options & OPT_SMALLPAGE) {
682		if (ns->geom.totsz <= (32 << 20)) {
683			ns->geom.pgaddrbytes  = 3;
684			ns->geom.secaddrbytes = 2;
685		} else {
686			ns->geom.pgaddrbytes  = 4;
687			ns->geom.secaddrbytes = 3;
688		}
689	} else {
690		if (ns->geom.totsz <= (128 << 20)) {
691			ns->geom.pgaddrbytes  = 4;
692			ns->geom.secaddrbytes = 2;
693		} else {
694			ns->geom.pgaddrbytes  = 5;
695			ns->geom.secaddrbytes = 3;
696		}
697	}
698
699	/* Fill the partition_info structure */
700	if (parts_num > ARRAY_SIZE(ns->partitions)) {
701		NS_ERR("too many partitions.\n");
702		return -EINVAL;
703	}
704	remains = ns->geom.totsz;
705	next_offset = 0;
706	for (i = 0; i < parts_num; ++i) {
707		uint64_t part_sz = (uint64_t)parts[i] * ns->geom.secsz;
708
709		if (!part_sz || part_sz > remains) {
710			NS_ERR("bad partition size.\n");
711			return -EINVAL;
712		}
713		ns->partitions[i].name = ns_get_partition_name(i);
714		if (!ns->partitions[i].name) {
715			NS_ERR("unable to allocate memory.\n");
716			return -ENOMEM;
717		}
718		ns->partitions[i].offset = next_offset;
719		ns->partitions[i].size   = part_sz;
720		next_offset += ns->partitions[i].size;
721		remains -= ns->partitions[i].size;
722	}
723	ns->nbparts = parts_num;
724	if (remains) {
725		if (parts_num + 1 > ARRAY_SIZE(ns->partitions)) {
726			NS_ERR("too many partitions.\n");
727			ret = -EINVAL;
728			goto free_partition_names;
729		}
730		ns->partitions[i].name = ns_get_partition_name(i);
731		if (!ns->partitions[i].name) {
732			NS_ERR("unable to allocate memory.\n");
733			ret = -ENOMEM;
734			goto free_partition_names;
735		}
736		ns->partitions[i].offset = next_offset;
737		ns->partitions[i].size   = remains;
738		ns->nbparts += 1;
739	}
740
741	if (ns->busw == 16)
742		NS_WARN("16-bit flashes support wasn't tested\n");
743
744	printk("flash size: %llu MiB\n",
745			(unsigned long long)ns->geom.totsz >> 20);
746	printk("page size: %u bytes\n",         ns->geom.pgsz);
747	printk("OOB area size: %u bytes\n",     ns->geom.oobsz);
748	printk("sector size: %u KiB\n",         ns->geom.secsz >> 10);
749	printk("pages number: %u\n",            ns->geom.pgnum);
750	printk("pages per sector: %u\n",        ns->geom.pgsec);
751	printk("bus width: %u\n",               ns->busw);
752	printk("bits in sector size: %u\n",     ns->geom.secshift);
753	printk("bits in page size: %u\n",       ns->geom.pgshift);
754	printk("bits in OOB size: %u\n",	ffs(ns->geom.oobsz) - 1);
755	printk("flash size with OOB: %llu KiB\n",
756			(unsigned long long)ns->geom.totszoob >> 10);
757	printk("page address bytes: %u\n",      ns->geom.pgaddrbytes);
758	printk("sector address bytes: %u\n",    ns->geom.secaddrbytes);
759	printk("options: %#x\n",                ns->options);
760
761	ret = ns_alloc_device(ns);
762	if (ret)
763		goto free_partition_names;
764
765	/* Allocate / initialize the internal buffer */
766	ns->buf.byte = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
767	if (!ns->buf.byte) {
768		NS_ERR("init_nandsim: unable to allocate %u bytes for the internal buffer\n",
769			ns->geom.pgszoob);
770		ret = -ENOMEM;
771		goto free_device;
772	}
773	memset(ns->buf.byte, 0xFF, ns->geom.pgszoob);
774
775	return 0;
776
777free_device:
778	ns_free_device(ns);
779free_partition_names:
780	for (i = 0; i < ARRAY_SIZE(ns->partitions); ++i)
781		kfree(ns->partitions[i].name);
782
783	return ret;
784}
785
786/*
787 * Free the nandsim structure.
788 */
789static void ns_free(struct nandsim *ns)
790{
791	int i;
792
793	for (i = 0; i < ARRAY_SIZE(ns->partitions); ++i)
794		kfree(ns->partitions[i].name);
795
796	kfree(ns->buf.byte);
797	ns_free_device(ns);
798
799	return;
800}
801
802static int ns_parse_badblocks(struct nandsim *ns, struct mtd_info *mtd)
803{
804	char *w;
805	int zero_ok;
806	unsigned int erase_block_no;
807	loff_t offset;
808
809	if (!badblocks)
810		return 0;
811	w = badblocks;
812	do {
813		zero_ok = (*w == '0' ? 1 : 0);
814		erase_block_no = simple_strtoul(w, &w, 0);
815		if (!zero_ok && !erase_block_no) {
816			NS_ERR("invalid badblocks.\n");
817			return -EINVAL;
818		}
819		offset = (loff_t)erase_block_no * ns->geom.secsz;
820		if (mtd_block_markbad(mtd, offset)) {
821			NS_ERR("invalid badblocks.\n");
822			return -EINVAL;
823		}
824		if (*w == ',')
825			w += 1;
826	} while (*w);
827	return 0;
828}
829
830static int ns_parse_weakblocks(void)
831{
832	char *w;
833	int zero_ok;
834	unsigned int erase_block_no;
835	unsigned int max_erases;
836	struct weak_block *wb;
837
838	if (!weakblocks)
839		return 0;
840	w = weakblocks;
841	do {
842		zero_ok = (*w == '0' ? 1 : 0);
843		erase_block_no = simple_strtoul(w, &w, 0);
844		if (!zero_ok && !erase_block_no) {
845			NS_ERR("invalid weakblocks.\n");
846			return -EINVAL;
847		}
848		max_erases = 3;
849		if (*w == ':') {
850			w += 1;
851			max_erases = simple_strtoul(w, &w, 0);
852		}
853		if (*w == ',')
854			w += 1;
855		wb = kzalloc(sizeof(*wb), GFP_KERNEL);
856		if (!wb) {
857			NS_ERR("unable to allocate memory.\n");
858			return -ENOMEM;
859		}
860		wb->erase_block_no = erase_block_no;
861		wb->max_erases = max_erases;
862		list_add(&wb->list, &weak_blocks);
863	} while (*w);
864	return 0;
865}
866
867static int ns_erase_error(unsigned int erase_block_no)
868{
869	struct weak_block *wb;
870
871	list_for_each_entry(wb, &weak_blocks, list)
872		if (wb->erase_block_no == erase_block_no) {
873			if (wb->erases_done >= wb->max_erases)
874				return 1;
875			wb->erases_done += 1;
876			return 0;
877		}
878	return 0;
879}
880
881static int ns_parse_weakpages(void)
882{
883	char *w;
884	int zero_ok;
885	unsigned int page_no;
886	unsigned int max_writes;
887	struct weak_page *wp;
888
889	if (!weakpages)
890		return 0;
891	w = weakpages;
892	do {
893		zero_ok = (*w == '0' ? 1 : 0);
894		page_no = simple_strtoul(w, &w, 0);
895		if (!zero_ok && !page_no) {
896			NS_ERR("invalid weakpages.\n");
897			return -EINVAL;
898		}
899		max_writes = 3;
900		if (*w == ':') {
901			w += 1;
902			max_writes = simple_strtoul(w, &w, 0);
903		}
904		if (*w == ',')
905			w += 1;
906		wp = kzalloc(sizeof(*wp), GFP_KERNEL);
907		if (!wp) {
908			NS_ERR("unable to allocate memory.\n");
909			return -ENOMEM;
910		}
911		wp->page_no = page_no;
912		wp->max_writes = max_writes;
913		list_add(&wp->list, &weak_pages);
914	} while (*w);
915	return 0;
916}
917
918static int ns_write_error(unsigned int page_no)
919{
920	struct weak_page *wp;
921
922	list_for_each_entry(wp, &weak_pages, list)
923		if (wp->page_no == page_no) {
924			if (wp->writes_done >= wp->max_writes)
925				return 1;
926			wp->writes_done += 1;
927			return 0;
928		}
929	return 0;
930}
931
932static int ns_parse_gravepages(void)
933{
934	char *g;
935	int zero_ok;
936	unsigned int page_no;
937	unsigned int max_reads;
938	struct grave_page *gp;
939
940	if (!gravepages)
941		return 0;
942	g = gravepages;
943	do {
944		zero_ok = (*g == '0' ? 1 : 0);
945		page_no = simple_strtoul(g, &g, 0);
946		if (!zero_ok && !page_no) {
947			NS_ERR("invalid gravepagess.\n");
948			return -EINVAL;
949		}
950		max_reads = 3;
951		if (*g == ':') {
952			g += 1;
953			max_reads = simple_strtoul(g, &g, 0);
954		}
955		if (*g == ',')
956			g += 1;
957		gp = kzalloc(sizeof(*gp), GFP_KERNEL);
958		if (!gp) {
959			NS_ERR("unable to allocate memory.\n");
960			return -ENOMEM;
961		}
962		gp->page_no = page_no;
963		gp->max_reads = max_reads;
964		list_add(&gp->list, &grave_pages);
965	} while (*g);
966	return 0;
967}
968
969static int ns_read_error(unsigned int page_no)
970{
971	struct grave_page *gp;
972
973	list_for_each_entry(gp, &grave_pages, list)
974		if (gp->page_no == page_no) {
975			if (gp->reads_done >= gp->max_reads)
976				return 1;
977			gp->reads_done += 1;
978			return 0;
979		}
980	return 0;
981}
982
983static int ns_setup_wear_reporting(struct mtd_info *mtd)
984{
985	wear_eb_count = div_u64(mtd->size, mtd->erasesize);
986	erase_block_wear = kcalloc(wear_eb_count, sizeof(unsigned long), GFP_KERNEL);
987	if (!erase_block_wear) {
988		NS_ERR("Too many erase blocks for wear reporting\n");
989		return -ENOMEM;
990	}
991	return 0;
992}
993
994static void ns_update_wear(unsigned int erase_block_no)
995{
996	if (!erase_block_wear)
997		return;
998	total_wear += 1;
999	/*
1000	 * TODO: Notify this through a debugfs entry,
1001	 * instead of showing an error message.
1002	 */
1003	if (total_wear == 0)
1004		NS_ERR("Erase counter total overflow\n");
1005	erase_block_wear[erase_block_no] += 1;
1006	if (erase_block_wear[erase_block_no] == 0)
1007		NS_ERR("Erase counter overflow for erase block %u\n", erase_block_no);
1008}
1009
1010/*
1011 * Returns the string representation of 'state' state.
1012 */
1013static char *ns_get_state_name(uint32_t state)
1014{
1015	switch (NS_STATE(state)) {
1016		case STATE_CMD_READ0:
1017			return "STATE_CMD_READ0";
1018		case STATE_CMD_READ1:
1019			return "STATE_CMD_READ1";
1020		case STATE_CMD_PAGEPROG:
1021			return "STATE_CMD_PAGEPROG";
1022		case STATE_CMD_READOOB:
1023			return "STATE_CMD_READOOB";
1024		case STATE_CMD_READSTART:
1025			return "STATE_CMD_READSTART";
1026		case STATE_CMD_ERASE1:
1027			return "STATE_CMD_ERASE1";
1028		case STATE_CMD_STATUS:
1029			return "STATE_CMD_STATUS";
1030		case STATE_CMD_SEQIN:
1031			return "STATE_CMD_SEQIN";
1032		case STATE_CMD_READID:
1033			return "STATE_CMD_READID";
1034		case STATE_CMD_ERASE2:
1035			return "STATE_CMD_ERASE2";
1036		case STATE_CMD_RESET:
1037			return "STATE_CMD_RESET";
1038		case STATE_CMD_RNDOUT:
1039			return "STATE_CMD_RNDOUT";
1040		case STATE_CMD_RNDOUTSTART:
1041			return "STATE_CMD_RNDOUTSTART";
1042		case STATE_ADDR_PAGE:
1043			return "STATE_ADDR_PAGE";
1044		case STATE_ADDR_SEC:
1045			return "STATE_ADDR_SEC";
1046		case STATE_ADDR_ZERO:
1047			return "STATE_ADDR_ZERO";
1048		case STATE_ADDR_COLUMN:
1049			return "STATE_ADDR_COLUMN";
1050		case STATE_DATAIN:
1051			return "STATE_DATAIN";
1052		case STATE_DATAOUT:
1053			return "STATE_DATAOUT";
1054		case STATE_DATAOUT_ID:
1055			return "STATE_DATAOUT_ID";
1056		case STATE_DATAOUT_STATUS:
1057			return "STATE_DATAOUT_STATUS";
1058		case STATE_READY:
1059			return "STATE_READY";
1060		case STATE_UNKNOWN:
1061			return "STATE_UNKNOWN";
1062	}
1063
1064	NS_ERR("get_state_name: unknown state, BUG\n");
1065	return NULL;
1066}
1067
1068/*
1069 * Check if command is valid.
1070 *
1071 * RETURNS: 1 if wrong command, 0 if right.
1072 */
1073static int ns_check_command(int cmd)
1074{
1075	switch (cmd) {
1076
1077	case NAND_CMD_READ0:
1078	case NAND_CMD_READ1:
1079	case NAND_CMD_READSTART:
1080	case NAND_CMD_PAGEPROG:
1081	case NAND_CMD_READOOB:
1082	case NAND_CMD_ERASE1:
1083	case NAND_CMD_STATUS:
1084	case NAND_CMD_SEQIN:
1085	case NAND_CMD_READID:
1086	case NAND_CMD_ERASE2:
1087	case NAND_CMD_RESET:
1088	case NAND_CMD_RNDOUT:
1089	case NAND_CMD_RNDOUTSTART:
1090		return 0;
1091
1092	default:
1093		return 1;
1094	}
1095}
1096
1097/*
1098 * Returns state after command is accepted by command number.
1099 */
1100static uint32_t ns_get_state_by_command(unsigned command)
1101{
1102	switch (command) {
1103		case NAND_CMD_READ0:
1104			return STATE_CMD_READ0;
1105		case NAND_CMD_READ1:
1106			return STATE_CMD_READ1;
1107		case NAND_CMD_PAGEPROG:
1108			return STATE_CMD_PAGEPROG;
1109		case NAND_CMD_READSTART:
1110			return STATE_CMD_READSTART;
1111		case NAND_CMD_READOOB:
1112			return STATE_CMD_READOOB;
1113		case NAND_CMD_ERASE1:
1114			return STATE_CMD_ERASE1;
1115		case NAND_CMD_STATUS:
1116			return STATE_CMD_STATUS;
1117		case NAND_CMD_SEQIN:
1118			return STATE_CMD_SEQIN;
1119		case NAND_CMD_READID:
1120			return STATE_CMD_READID;
1121		case NAND_CMD_ERASE2:
1122			return STATE_CMD_ERASE2;
1123		case NAND_CMD_RESET:
1124			return STATE_CMD_RESET;
1125		case NAND_CMD_RNDOUT:
1126			return STATE_CMD_RNDOUT;
1127		case NAND_CMD_RNDOUTSTART:
1128			return STATE_CMD_RNDOUTSTART;
1129	}
1130
1131	NS_ERR("get_state_by_command: unknown command, BUG\n");
1132	return 0;
1133}
1134
1135/*
1136 * Move an address byte to the correspondent internal register.
1137 */
1138static inline void ns_accept_addr_byte(struct nandsim *ns, u_char bt)
1139{
1140	uint byte = (uint)bt;
1141
1142	if (ns->regs.count < (ns->geom.pgaddrbytes - ns->geom.secaddrbytes))
1143		ns->regs.column |= (byte << 8 * ns->regs.count);
1144	else {
1145		ns->regs.row |= (byte << 8 * (ns->regs.count -
1146						ns->geom.pgaddrbytes +
1147						ns->geom.secaddrbytes));
1148	}
1149
1150	return;
1151}
1152
1153/*
1154 * Switch to STATE_READY state.
1155 */
1156static inline void ns_switch_to_ready_state(struct nandsim *ns, u_char status)
1157{
1158	NS_DBG("switch_to_ready_state: switch to %s state\n",
1159	       ns_get_state_name(STATE_READY));
1160
1161	ns->state       = STATE_READY;
1162	ns->nxstate     = STATE_UNKNOWN;
1163	ns->op          = NULL;
1164	ns->npstates    = 0;
1165	ns->stateidx    = 0;
1166	ns->regs.num    = 0;
1167	ns->regs.count  = 0;
1168	ns->regs.off    = 0;
1169	ns->regs.row    = 0;
1170	ns->regs.column = 0;
1171	ns->regs.status = status;
1172}
1173
1174/*
1175 * If the operation isn't known yet, try to find it in the global array
1176 * of supported operations.
1177 *
1178 * Operation can be unknown because of the following.
1179 *   1. New command was accepted and this is the first call to find the
1180 *      correspondent states chain. In this case ns->npstates = 0;
1181 *   2. There are several operations which begin with the same command(s)
1182 *      (for example program from the second half and read from the
1183 *      second half operations both begin with the READ1 command). In this
1184 *      case the ns->pstates[] array contains previous states.
1185 *
1186 * Thus, the function tries to find operation containing the following
1187 * states (if the 'flag' parameter is 0):
1188 *    ns->pstates[0], ... ns->pstates[ns->npstates], ns->state
1189 *
1190 * If (one and only one) matching operation is found, it is accepted (
1191 * ns->ops, ns->state, ns->nxstate are initialized, ns->npstate is
1192 * zeroed).
1193 *
1194 * If there are several matches, the current state is pushed to the
1195 * ns->pstates.
1196 *
1197 * The operation can be unknown only while commands are input to the chip.
1198 * As soon as address command is accepted, the operation must be known.
1199 * In such situation the function is called with 'flag' != 0, and the
1200 * operation is searched using the following pattern:
1201 *     ns->pstates[0], ... ns->pstates[ns->npstates], <address input>
1202 *
1203 * It is supposed that this pattern must either match one operation or
1204 * none. There can't be ambiguity in that case.
1205 *
1206 * If no matches found, the function does the following:
1207 *   1. if there are saved states present, try to ignore them and search
1208 *      again only using the last command. If nothing was found, switch
1209 *      to the STATE_READY state.
1210 *   2. if there are no saved states, switch to the STATE_READY state.
1211 *
1212 * RETURNS: -2 - no matched operations found.
1213 *          -1 - several matches.
1214 *           0 - operation is found.
1215 */
1216static int ns_find_operation(struct nandsim *ns, uint32_t flag)
1217{
1218	int opsfound = 0;
1219	int i, j, idx = 0;
1220
1221	for (i = 0; i < NS_OPER_NUM; i++) {
1222
1223		int found = 1;
1224
1225		if (!(ns->options & ops[i].reqopts))
1226			/* Ignore operations we can't perform */
1227			continue;
1228
1229		if (flag) {
1230			if (!(ops[i].states[ns->npstates] & STATE_ADDR_MASK))
1231				continue;
1232		} else {
1233			if (NS_STATE(ns->state) != NS_STATE(ops[i].states[ns->npstates]))
1234				continue;
1235		}
1236
1237		for (j = 0; j < ns->npstates; j++)
1238			if (NS_STATE(ops[i].states[j]) != NS_STATE(ns->pstates[j])
1239				&& (ns->options & ops[idx].reqopts)) {
1240				found = 0;
1241				break;
1242			}
1243
1244		if (found) {
1245			idx = i;
1246			opsfound += 1;
1247		}
1248	}
1249
1250	if (opsfound == 1) {
1251		/* Exact match */
1252		ns->op = &ops[idx].states[0];
1253		if (flag) {
1254			/*
1255			 * In this case the find_operation function was
1256			 * called when address has just began input. But it isn't
1257			 * yet fully input and the current state must
1258			 * not be one of STATE_ADDR_*, but the STATE_ADDR_*
1259			 * state must be the next state (ns->nxstate).
1260			 */
1261			ns->stateidx = ns->npstates - 1;
1262		} else {
1263			ns->stateidx = ns->npstates;
1264		}
1265		ns->npstates = 0;
1266		ns->state = ns->op[ns->stateidx];
1267		ns->nxstate = ns->op[ns->stateidx + 1];
1268		NS_DBG("find_operation: operation found, index: %d, state: %s, nxstate %s\n",
1269		       idx, ns_get_state_name(ns->state),
1270		       ns_get_state_name(ns->nxstate));
1271		return 0;
1272	}
1273
1274	if (opsfound == 0) {
1275		/* Nothing was found. Try to ignore previous commands (if any) and search again */
1276		if (ns->npstates != 0) {
1277			NS_DBG("find_operation: no operation found, try again with state %s\n",
1278			       ns_get_state_name(ns->state));
1279			ns->npstates = 0;
1280			return ns_find_operation(ns, 0);
1281
1282		}
1283		NS_DBG("find_operation: no operations found\n");
1284		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1285		return -2;
1286	}
1287
1288	if (flag) {
1289		/* This shouldn't happen */
1290		NS_DBG("find_operation: BUG, operation must be known if address is input\n");
1291		return -2;
1292	}
1293
1294	NS_DBG("find_operation: there is still ambiguity\n");
1295
1296	ns->pstates[ns->npstates++] = ns->state;
1297
1298	return -1;
1299}
1300
1301static void ns_put_pages(struct nandsim *ns)
1302{
1303	int i;
1304
1305	for (i = 0; i < ns->held_cnt; i++)
1306		put_page(ns->held_pages[i]);
1307}
1308
1309/* Get page cache pages in advance to provide NOFS memory allocation */
1310static int ns_get_pages(struct nandsim *ns, struct file *file, size_t count,
1311			loff_t pos)
1312{
1313	pgoff_t index, start_index, end_index;
1314	struct page *page;
1315	struct address_space *mapping = file->f_mapping;
1316
1317	start_index = pos >> PAGE_SHIFT;
1318	end_index = (pos + count - 1) >> PAGE_SHIFT;
1319	if (end_index - start_index + 1 > NS_MAX_HELD_PAGES)
1320		return -EINVAL;
1321	ns->held_cnt = 0;
1322	for (index = start_index; index <= end_index; index++) {
1323		page = find_get_page(mapping, index);
1324		if (page == NULL) {
1325			page = find_or_create_page(mapping, index, GFP_NOFS);
1326			if (page == NULL) {
1327				write_inode_now(mapping->host, 1);
1328				page = find_or_create_page(mapping, index, GFP_NOFS);
1329			}
1330			if (page == NULL) {
1331				ns_put_pages(ns);
1332				return -ENOMEM;
1333			}
1334			unlock_page(page);
1335		}
1336		ns->held_pages[ns->held_cnt++] = page;
1337	}
1338	return 0;
1339}
1340
1341static ssize_t ns_read_file(struct nandsim *ns, struct file *file, void *buf,
1342			    size_t count, loff_t pos)
1343{
1344	ssize_t tx;
1345	int err;
1346	unsigned int noreclaim_flag;
1347
1348	err = ns_get_pages(ns, file, count, pos);
1349	if (err)
1350		return err;
1351	noreclaim_flag = memalloc_noreclaim_save();
1352	tx = kernel_read(file, buf, count, &pos);
1353	memalloc_noreclaim_restore(noreclaim_flag);
1354	ns_put_pages(ns);
1355	return tx;
1356}
1357
1358static ssize_t ns_write_file(struct nandsim *ns, struct file *file, void *buf,
1359			     size_t count, loff_t pos)
1360{
1361	ssize_t tx;
1362	int err;
1363	unsigned int noreclaim_flag;
1364
1365	err = ns_get_pages(ns, file, count, pos);
1366	if (err)
1367		return err;
1368	noreclaim_flag = memalloc_noreclaim_save();
1369	tx = kernel_write(file, buf, count, &pos);
1370	memalloc_noreclaim_restore(noreclaim_flag);
1371	ns_put_pages(ns);
1372	return tx;
1373}
1374
1375/*
1376 * Returns a pointer to the current page.
1377 */
1378static inline union ns_mem *NS_GET_PAGE(struct nandsim *ns)
1379{
1380	return &(ns->pages[ns->regs.row]);
1381}
1382
1383/*
1384 * Retuns a pointer to the current byte, within the current page.
1385 */
1386static inline u_char *NS_PAGE_BYTE_OFF(struct nandsim *ns)
1387{
1388	return NS_GET_PAGE(ns)->byte + NS_PAGE_BYTE_SHIFT(ns);
1389}
1390
1391static int ns_do_read_error(struct nandsim *ns, int num)
1392{
1393	unsigned int page_no = ns->regs.row;
1394
1395	if (ns_read_error(page_no)) {
1396		get_random_bytes(ns->buf.byte, num);
1397		NS_WARN("simulating read error in page %u\n", page_no);
1398		return 1;
1399	}
1400	return 0;
1401}
1402
1403static void ns_do_bit_flips(struct nandsim *ns, int num)
1404{
1405	if (bitflips && get_random_u16() < (1 << 6)) {
1406		int flips = 1;
1407		if (bitflips > 1)
1408			flips = get_random_u32_inclusive(1, bitflips);
1409		while (flips--) {
1410			int pos = get_random_u32_below(num * 8);
1411			ns->buf.byte[pos / 8] ^= (1 << (pos % 8));
1412			NS_WARN("read_page: flipping bit %d in page %d "
1413				"reading from %d ecc: corrected=%u failed=%u\n",
1414				pos, ns->regs.row, NS_PAGE_BYTE_SHIFT(ns),
1415				nsmtd->ecc_stats.corrected, nsmtd->ecc_stats.failed);
1416		}
1417	}
1418}
1419
1420/*
1421 * Fill the NAND buffer with data read from the specified page.
1422 */
1423static void ns_read_page(struct nandsim *ns, int num)
1424{
1425	union ns_mem *mypage;
1426
1427	if (ns->cfile) {
1428		if (!test_bit(ns->regs.row, ns->pages_written)) {
1429			NS_DBG("read_page: page %d not written\n", ns->regs.row);
1430			memset(ns->buf.byte, 0xFF, num);
1431		} else {
1432			loff_t pos;
1433			ssize_t tx;
1434
1435			NS_DBG("read_page: page %d written, reading from %d\n",
1436				ns->regs.row, NS_PAGE_BYTE_SHIFT(ns));
1437			if (ns_do_read_error(ns, num))
1438				return;
1439			pos = (loff_t)NS_RAW_OFFSET(ns) + ns->regs.off;
1440			tx = ns_read_file(ns, ns->cfile, ns->buf.byte, num,
1441					  pos);
1442			if (tx != num) {
1443				NS_ERR("read_page: read error for page %d ret %ld\n", ns->regs.row, (long)tx);
1444				return;
1445			}
1446			ns_do_bit_flips(ns, num);
1447		}
1448		return;
1449	}
1450
1451	mypage = NS_GET_PAGE(ns);
1452	if (mypage->byte == NULL) {
1453		NS_DBG("read_page: page %d not allocated\n", ns->regs.row);
1454		memset(ns->buf.byte, 0xFF, num);
1455	} else {
1456		NS_DBG("read_page: page %d allocated, reading from %d\n",
1457			ns->regs.row, NS_PAGE_BYTE_SHIFT(ns));
1458		if (ns_do_read_error(ns, num))
1459			return;
1460		memcpy(ns->buf.byte, NS_PAGE_BYTE_OFF(ns), num);
1461		ns_do_bit_flips(ns, num);
1462	}
1463}
1464
1465/*
1466 * Erase all pages in the specified sector.
1467 */
1468static void ns_erase_sector(struct nandsim *ns)
1469{
1470	union ns_mem *mypage;
1471	int i;
1472
1473	if (ns->cfile) {
1474		for (i = 0; i < ns->geom.pgsec; i++)
1475			if (__test_and_clear_bit(ns->regs.row + i,
1476						 ns->pages_written)) {
1477				NS_DBG("erase_sector: freeing page %d\n", ns->regs.row + i);
1478			}
1479		return;
1480	}
1481
1482	mypage = NS_GET_PAGE(ns);
1483	for (i = 0; i < ns->geom.pgsec; i++) {
1484		if (mypage->byte != NULL) {
1485			NS_DBG("erase_sector: freeing page %d\n", ns->regs.row+i);
1486			kmem_cache_free(ns->nand_pages_slab, mypage->byte);
1487			mypage->byte = NULL;
1488		}
1489		mypage++;
1490	}
1491}
1492
1493/*
1494 * Program the specified page with the contents from the NAND buffer.
1495 */
1496static int ns_prog_page(struct nandsim *ns, int num)
1497{
1498	int i;
1499	union ns_mem *mypage;
1500	u_char *pg_off;
1501
1502	if (ns->cfile) {
1503		loff_t off;
1504		ssize_t tx;
1505		int all;
1506
1507		NS_DBG("prog_page: writing page %d\n", ns->regs.row);
1508		pg_off = ns->file_buf + NS_PAGE_BYTE_SHIFT(ns);
1509		off = (loff_t)NS_RAW_OFFSET(ns) + ns->regs.off;
1510		if (!test_bit(ns->regs.row, ns->pages_written)) {
1511			all = 1;
1512			memset(ns->file_buf, 0xff, ns->geom.pgszoob);
1513		} else {
1514			all = 0;
1515			tx = ns_read_file(ns, ns->cfile, pg_off, num, off);
1516			if (tx != num) {
1517				NS_ERR("prog_page: read error for page %d ret %ld\n", ns->regs.row, (long)tx);
1518				return -1;
1519			}
1520		}
1521		for (i = 0; i < num; i++)
1522			pg_off[i] &= ns->buf.byte[i];
1523		if (all) {
1524			loff_t pos = (loff_t)ns->regs.row * ns->geom.pgszoob;
1525			tx = ns_write_file(ns, ns->cfile, ns->file_buf,
1526					   ns->geom.pgszoob, pos);
1527			if (tx != ns->geom.pgszoob) {
1528				NS_ERR("prog_page: write error for page %d ret %ld\n", ns->regs.row, (long)tx);
1529				return -1;
1530			}
1531			__set_bit(ns->regs.row, ns->pages_written);
1532		} else {
1533			tx = ns_write_file(ns, ns->cfile, pg_off, num, off);
1534			if (tx != num) {
1535				NS_ERR("prog_page: write error for page %d ret %ld\n", ns->regs.row, (long)tx);
1536				return -1;
1537			}
1538		}
1539		return 0;
1540	}
1541
1542	mypage = NS_GET_PAGE(ns);
1543	if (mypage->byte == NULL) {
1544		NS_DBG("prog_page: allocating page %d\n", ns->regs.row);
1545		/*
1546		 * We allocate memory with GFP_NOFS because a flash FS may
1547		 * utilize this. If it is holding an FS lock, then gets here,
1548		 * then kernel memory alloc runs writeback which goes to the FS
1549		 * again and deadlocks. This was seen in practice.
1550		 */
1551		mypage->byte = kmem_cache_alloc(ns->nand_pages_slab, GFP_NOFS);
1552		if (mypage->byte == NULL) {
1553			NS_ERR("prog_page: error allocating memory for page %d\n", ns->regs.row);
1554			return -1;
1555		}
1556		memset(mypage->byte, 0xFF, ns->geom.pgszoob);
1557	}
1558
1559	pg_off = NS_PAGE_BYTE_OFF(ns);
1560	for (i = 0; i < num; i++)
1561		pg_off[i] &= ns->buf.byte[i];
1562
1563	return 0;
1564}
1565
1566/*
1567 * If state has any action bit, perform this action.
1568 *
1569 * RETURNS: 0 if success, -1 if error.
1570 */
1571static int ns_do_state_action(struct nandsim *ns, uint32_t action)
1572{
1573	int num;
1574	int busdiv = ns->busw == 8 ? 1 : 2;
1575	unsigned int erase_block_no, page_no;
1576
1577	action &= ACTION_MASK;
1578
1579	/* Check that page address input is correct */
1580	if (action != ACTION_SECERASE && ns->regs.row >= ns->geom.pgnum) {
1581		NS_WARN("do_state_action: wrong page number (%#x)\n", ns->regs.row);
1582		return -1;
1583	}
1584
1585	switch (action) {
1586
1587	case ACTION_CPY:
1588		/*
1589		 * Copy page data to the internal buffer.
1590		 */
1591
1592		/* Column shouldn't be very large */
1593		if (ns->regs.column >= (ns->geom.pgszoob - ns->regs.off)) {
1594			NS_ERR("do_state_action: column number is too large\n");
1595			break;
1596		}
1597		num = ns->geom.pgszoob - NS_PAGE_BYTE_SHIFT(ns);
1598		ns_read_page(ns, num);
1599
1600		NS_DBG("do_state_action: (ACTION_CPY:) copy %d bytes to int buf, raw offset %d\n",
1601			num, NS_RAW_OFFSET(ns) + ns->regs.off);
1602
1603		if (ns->regs.off == 0)
1604			NS_LOG("read page %d\n", ns->regs.row);
1605		else if (ns->regs.off < ns->geom.pgsz)
1606			NS_LOG("read page %d (second half)\n", ns->regs.row);
1607		else
1608			NS_LOG("read OOB of page %d\n", ns->regs.row);
1609
1610		NS_UDELAY(access_delay);
1611		NS_UDELAY(input_cycle * ns->geom.pgsz / 1000 / busdiv);
1612
1613		break;
1614
1615	case ACTION_SECERASE:
1616		/*
1617		 * Erase sector.
1618		 */
1619
1620		if (ns->lines.wp) {
1621			NS_ERR("do_state_action: device is write-protected, ignore sector erase\n");
1622			return -1;
1623		}
1624
1625		if (ns->regs.row >= ns->geom.pgnum - ns->geom.pgsec
1626			|| (ns->regs.row & ~(ns->geom.secsz - 1))) {
1627			NS_ERR("do_state_action: wrong sector address (%#x)\n", ns->regs.row);
1628			return -1;
1629		}
1630
1631		ns->regs.row = (ns->regs.row <<
1632				8 * (ns->geom.pgaddrbytes - ns->geom.secaddrbytes)) | ns->regs.column;
1633		ns->regs.column = 0;
1634
1635		erase_block_no = ns->regs.row >> (ns->geom.secshift - ns->geom.pgshift);
1636
1637		NS_DBG("do_state_action: erase sector at address %#x, off = %d\n",
1638				ns->regs.row, NS_RAW_OFFSET(ns));
1639		NS_LOG("erase sector %u\n", erase_block_no);
1640
1641		ns_erase_sector(ns);
1642
1643		NS_MDELAY(erase_delay);
1644
1645		if (erase_block_wear)
1646			ns_update_wear(erase_block_no);
1647
1648		if (ns_erase_error(erase_block_no)) {
1649			NS_WARN("simulating erase failure in erase block %u\n", erase_block_no);
1650			return -1;
1651		}
1652
1653		break;
1654
1655	case ACTION_PRGPAGE:
1656		/*
1657		 * Program page - move internal buffer data to the page.
1658		 */
1659
1660		if (ns->lines.wp) {
1661			NS_WARN("do_state_action: device is write-protected, programm\n");
1662			return -1;
1663		}
1664
1665		num = ns->geom.pgszoob - NS_PAGE_BYTE_SHIFT(ns);
1666		if (num != ns->regs.count) {
1667			NS_ERR("do_state_action: too few bytes were input (%d instead of %d)\n",
1668					ns->regs.count, num);
1669			return -1;
1670		}
1671
1672		if (ns_prog_page(ns, num) == -1)
1673			return -1;
1674
1675		page_no = ns->regs.row;
1676
1677		NS_DBG("do_state_action: copy %d bytes from int buf to (%#x, %#x), raw off = %d\n",
1678			num, ns->regs.row, ns->regs.column, NS_RAW_OFFSET(ns) + ns->regs.off);
1679		NS_LOG("programm page %d\n", ns->regs.row);
1680
1681		NS_UDELAY(programm_delay);
1682		NS_UDELAY(output_cycle * ns->geom.pgsz / 1000 / busdiv);
1683
1684		if (ns_write_error(page_no)) {
1685			NS_WARN("simulating write failure in page %u\n", page_no);
1686			return -1;
1687		}
1688
1689		break;
1690
1691	case ACTION_ZEROOFF:
1692		NS_DBG("do_state_action: set internal offset to 0\n");
1693		ns->regs.off = 0;
1694		break;
1695
1696	case ACTION_HALFOFF:
1697		if (!(ns->options & OPT_PAGE512_8BIT)) {
1698			NS_ERR("do_state_action: BUG! can't skip half of page for non-512"
1699				"byte page size 8x chips\n");
1700			return -1;
1701		}
1702		NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz/2);
1703		ns->regs.off = ns->geom.pgsz/2;
1704		break;
1705
1706	case ACTION_OOBOFF:
1707		NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz);
1708		ns->regs.off = ns->geom.pgsz;
1709		break;
1710
1711	default:
1712		NS_DBG("do_state_action: BUG! unknown action\n");
1713	}
1714
1715	return 0;
1716}
1717
1718/*
1719 * Switch simulator's state.
1720 */
1721static void ns_switch_state(struct nandsim *ns)
1722{
1723	if (ns->op) {
1724		/*
1725		 * The current operation have already been identified.
1726		 * Just follow the states chain.
1727		 */
1728
1729		ns->stateidx += 1;
1730		ns->state = ns->nxstate;
1731		ns->nxstate = ns->op[ns->stateidx + 1];
1732
1733		NS_DBG("switch_state: operation is known, switch to the next state, "
1734			"state: %s, nxstate: %s\n",
1735		       ns_get_state_name(ns->state),
1736		       ns_get_state_name(ns->nxstate));
1737	} else {
1738		/*
1739		 * We don't yet know which operation we perform.
1740		 * Try to identify it.
1741		 */
1742
1743		/*
1744		 *  The only event causing the switch_state function to
1745		 *  be called with yet unknown operation is new command.
1746		 */
1747		ns->state = ns_get_state_by_command(ns->regs.command);
1748
1749		NS_DBG("switch_state: operation is unknown, try to find it\n");
1750
1751		if (ns_find_operation(ns, 0))
1752			return;
1753	}
1754
1755	/* See, whether we need to do some action */
1756	if ((ns->state & ACTION_MASK) &&
1757	    ns_do_state_action(ns, ns->state) < 0) {
1758		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1759		return;
1760	}
1761
1762	/* For 16x devices column means the page offset in words */
1763	if ((ns->nxstate & STATE_ADDR_MASK) && ns->busw == 16) {
1764		NS_DBG("switch_state: double the column number for 16x device\n");
1765		ns->regs.column <<= 1;
1766	}
1767
1768	if (NS_STATE(ns->nxstate) == STATE_READY) {
1769		/*
1770		 * The current state is the last. Return to STATE_READY
1771		 */
1772
1773		u_char status = NS_STATUS_OK(ns);
1774
1775		/* In case of data states, see if all bytes were input/output */
1776		if ((ns->state & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK))
1777			&& ns->regs.count != ns->regs.num) {
1778			NS_WARN("switch_state: not all bytes were processed, %d left\n",
1779					ns->regs.num - ns->regs.count);
1780			status = NS_STATUS_FAILED(ns);
1781		}
1782
1783		NS_DBG("switch_state: operation complete, switch to STATE_READY state\n");
1784
1785		ns_switch_to_ready_state(ns, status);
1786
1787		return;
1788	} else if (ns->nxstate & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK)) {
1789		/*
1790		 * If the next state is data input/output, switch to it now
1791		 */
1792
1793		ns->state      = ns->nxstate;
1794		ns->nxstate    = ns->op[++ns->stateidx + 1];
1795		ns->regs.num   = ns->regs.count = 0;
1796
1797		NS_DBG("switch_state: the next state is data I/O, switch, "
1798			"state: %s, nxstate: %s\n",
1799		       ns_get_state_name(ns->state),
1800		       ns_get_state_name(ns->nxstate));
1801
1802		/*
1803		 * Set the internal register to the count of bytes which
1804		 * are expected to be input or output
1805		 */
1806		switch (NS_STATE(ns->state)) {
1807			case STATE_DATAIN:
1808			case STATE_DATAOUT:
1809				ns->regs.num = ns->geom.pgszoob - NS_PAGE_BYTE_SHIFT(ns);
1810				break;
1811
1812			case STATE_DATAOUT_ID:
1813				ns->regs.num = ns->geom.idbytes;
1814				break;
1815
1816			case STATE_DATAOUT_STATUS:
1817				ns->regs.count = ns->regs.num = 0;
1818				break;
1819
1820			default:
1821				NS_ERR("switch_state: BUG! unknown data state\n");
1822		}
1823
1824	} else if (ns->nxstate & STATE_ADDR_MASK) {
1825		/*
1826		 * If the next state is address input, set the internal
1827		 * register to the number of expected address bytes
1828		 */
1829
1830		ns->regs.count = 0;
1831
1832		switch (NS_STATE(ns->nxstate)) {
1833			case STATE_ADDR_PAGE:
1834				ns->regs.num = ns->geom.pgaddrbytes;
1835
1836				break;
1837			case STATE_ADDR_SEC:
1838				ns->regs.num = ns->geom.secaddrbytes;
1839				break;
1840
1841			case STATE_ADDR_ZERO:
1842				ns->regs.num = 1;
1843				break;
1844
1845			case STATE_ADDR_COLUMN:
1846				/* Column address is always 2 bytes */
1847				ns->regs.num = ns->geom.pgaddrbytes - ns->geom.secaddrbytes;
1848				break;
1849
1850			default:
1851				NS_ERR("switch_state: BUG! unknown address state\n");
1852		}
1853	} else {
1854		/*
1855		 * Just reset internal counters.
1856		 */
1857
1858		ns->regs.num = 0;
1859		ns->regs.count = 0;
1860	}
1861}
1862
1863static u_char ns_nand_read_byte(struct nand_chip *chip)
1864{
1865	struct nandsim *ns = nand_get_controller_data(chip);
1866	u_char outb = 0x00;
1867
1868	/* Sanity and correctness checks */
1869	if (!ns->lines.ce) {
1870		NS_ERR("read_byte: chip is disabled, return %#x\n", (uint)outb);
1871		return outb;
1872	}
1873	if (ns->lines.ale || ns->lines.cle) {
1874		NS_ERR("read_byte: ALE or CLE pin is high, return %#x\n", (uint)outb);
1875		return outb;
1876	}
1877	if (!(ns->state & STATE_DATAOUT_MASK)) {
1878		NS_WARN("read_byte: unexpected data output cycle, state is %s return %#x\n",
1879			ns_get_state_name(ns->state), (uint)outb);
1880		return outb;
1881	}
1882
1883	/* Status register may be read as many times as it is wanted */
1884	if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS) {
1885		NS_DBG("read_byte: return %#x status\n", ns->regs.status);
1886		return ns->regs.status;
1887	}
1888
1889	/* Check if there is any data in the internal buffer which may be read */
1890	if (ns->regs.count == ns->regs.num) {
1891		NS_WARN("read_byte: no more data to output, return %#x\n", (uint)outb);
1892		return outb;
1893	}
1894
1895	switch (NS_STATE(ns->state)) {
1896		case STATE_DATAOUT:
1897			if (ns->busw == 8) {
1898				outb = ns->buf.byte[ns->regs.count];
1899				ns->regs.count += 1;
1900			} else {
1901				outb = (u_char)cpu_to_le16(ns->buf.word[ns->regs.count >> 1]);
1902				ns->regs.count += 2;
1903			}
1904			break;
1905		case STATE_DATAOUT_ID:
1906			NS_DBG("read_byte: read ID byte %d, total = %d\n", ns->regs.count, ns->regs.num);
1907			outb = ns->ids[ns->regs.count];
1908			ns->regs.count += 1;
1909			break;
1910		default:
1911			BUG();
1912	}
1913
1914	if (ns->regs.count == ns->regs.num) {
1915		NS_DBG("read_byte: all bytes were read\n");
1916
1917		if (NS_STATE(ns->nxstate) == STATE_READY)
1918			ns_switch_state(ns);
1919	}
1920
1921	return outb;
1922}
1923
1924static void ns_nand_write_byte(struct nand_chip *chip, u_char byte)
1925{
1926	struct nandsim *ns = nand_get_controller_data(chip);
1927
1928	/* Sanity and correctness checks */
1929	if (!ns->lines.ce) {
1930		NS_ERR("write_byte: chip is disabled, ignore write\n");
1931		return;
1932	}
1933	if (ns->lines.ale && ns->lines.cle) {
1934		NS_ERR("write_byte: ALE and CLE pins are high simultaneously, ignore write\n");
1935		return;
1936	}
1937
1938	if (ns->lines.cle == 1) {
1939		/*
1940		 * The byte written is a command.
1941		 */
1942
1943		if (byte == NAND_CMD_RESET) {
1944			NS_LOG("reset chip\n");
1945			ns_switch_to_ready_state(ns, NS_STATUS_OK(ns));
1946			return;
1947		}
1948
1949		/* Check that the command byte is correct */
1950		if (ns_check_command(byte)) {
1951			NS_ERR("write_byte: unknown command %#x\n", (uint)byte);
1952			return;
1953		}
1954
1955		if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS
1956			|| NS_STATE(ns->state) == STATE_DATAOUT) {
1957			int row = ns->regs.row;
1958
1959			ns_switch_state(ns);
1960			if (byte == NAND_CMD_RNDOUT)
1961				ns->regs.row = row;
1962		}
1963
1964		/* Check if chip is expecting command */
1965		if (NS_STATE(ns->nxstate) != STATE_UNKNOWN && !(ns->nxstate & STATE_CMD_MASK)) {
1966			/* Do not warn if only 2 id bytes are read */
1967			if (!(ns->regs.command == NAND_CMD_READID &&
1968			    NS_STATE(ns->state) == STATE_DATAOUT_ID && ns->regs.count == 2)) {
1969				/*
1970				 * We are in situation when something else (not command)
1971				 * was expected but command was input. In this case ignore
1972				 * previous command(s)/state(s) and accept the last one.
1973				 */
1974				NS_WARN("write_byte: command (%#x) wasn't expected, expected state is %s, ignore previous states\n",
1975					(uint)byte,
1976					ns_get_state_name(ns->nxstate));
1977			}
1978			ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1979		}
1980
1981		NS_DBG("command byte corresponding to %s state accepted\n",
1982			ns_get_state_name(ns_get_state_by_command(byte)));
1983		ns->regs.command = byte;
1984		ns_switch_state(ns);
1985
1986	} else if (ns->lines.ale == 1) {
1987		/*
1988		 * The byte written is an address.
1989		 */
1990
1991		if (NS_STATE(ns->nxstate) == STATE_UNKNOWN) {
1992
1993			NS_DBG("write_byte: operation isn't known yet, identify it\n");
1994
1995			if (ns_find_operation(ns, 1) < 0)
1996				return;
1997
1998			if ((ns->state & ACTION_MASK) &&
1999			    ns_do_state_action(ns, ns->state) < 0) {
2000				ns_switch_to_ready_state(ns,
2001							 NS_STATUS_FAILED(ns));
2002				return;
2003			}
2004
2005			ns->regs.count = 0;
2006			switch (NS_STATE(ns->nxstate)) {
2007				case STATE_ADDR_PAGE:
2008					ns->regs.num = ns->geom.pgaddrbytes;
2009					break;
2010				case STATE_ADDR_SEC:
2011					ns->regs.num = ns->geom.secaddrbytes;
2012					break;
2013				case STATE_ADDR_ZERO:
2014					ns->regs.num = 1;
2015					break;
2016				default:
2017					BUG();
2018			}
2019		}
2020
2021		/* Check that chip is expecting address */
2022		if (!(ns->nxstate & STATE_ADDR_MASK)) {
2023			NS_ERR("write_byte: address (%#x) isn't expected, expected state is %s, switch to STATE_READY\n",
2024			       (uint)byte, ns_get_state_name(ns->nxstate));
2025			ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2026			return;
2027		}
2028
2029		/* Check if this is expected byte */
2030		if (ns->regs.count == ns->regs.num) {
2031			NS_ERR("write_byte: no more address bytes expected\n");
2032			ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2033			return;
2034		}
2035
2036		ns_accept_addr_byte(ns, byte);
2037
2038		ns->regs.count += 1;
2039
2040		NS_DBG("write_byte: address byte %#x was accepted (%d bytes input, %d expected)\n",
2041				(uint)byte, ns->regs.count, ns->regs.num);
2042
2043		if (ns->regs.count == ns->regs.num) {
2044			NS_DBG("address (%#x, %#x) is accepted\n", ns->regs.row, ns->regs.column);
2045			ns_switch_state(ns);
2046		}
2047
2048	} else {
2049		/*
2050		 * The byte written is an input data.
2051		 */
2052
2053		/* Check that chip is expecting data input */
2054		if (!(ns->state & STATE_DATAIN_MASK)) {
2055			NS_ERR("write_byte: data input (%#x) isn't expected, state is %s, switch to %s\n",
2056			       (uint)byte, ns_get_state_name(ns->state),
2057			       ns_get_state_name(STATE_READY));
2058			ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2059			return;
2060		}
2061
2062		/* Check if this is expected byte */
2063		if (ns->regs.count == ns->regs.num) {
2064			NS_WARN("write_byte: %u input bytes has already been accepted, ignore write\n",
2065					ns->regs.num);
2066			return;
2067		}
2068
2069		if (ns->busw == 8) {
2070			ns->buf.byte[ns->regs.count] = byte;
2071			ns->regs.count += 1;
2072		} else {
2073			ns->buf.word[ns->regs.count >> 1] = cpu_to_le16((uint16_t)byte);
2074			ns->regs.count += 2;
2075		}
2076	}
2077
2078	return;
2079}
2080
2081static void ns_nand_write_buf(struct nand_chip *chip, const u_char *buf,
2082			      int len)
2083{
2084	struct nandsim *ns = nand_get_controller_data(chip);
2085
2086	/* Check that chip is expecting data input */
2087	if (!(ns->state & STATE_DATAIN_MASK)) {
2088		NS_ERR("write_buf: data input isn't expected, state is %s, switch to STATE_READY\n",
2089		       ns_get_state_name(ns->state));
2090		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2091		return;
2092	}
2093
2094	/* Check if these are expected bytes */
2095	if (ns->regs.count + len > ns->regs.num) {
2096		NS_ERR("write_buf: too many input bytes\n");
2097		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2098		return;
2099	}
2100
2101	memcpy(ns->buf.byte + ns->regs.count, buf, len);
2102	ns->regs.count += len;
2103
2104	if (ns->regs.count == ns->regs.num) {
2105		NS_DBG("write_buf: %d bytes were written\n", ns->regs.count);
2106	}
2107}
2108
2109static void ns_nand_read_buf(struct nand_chip *chip, u_char *buf, int len)
2110{
2111	struct nandsim *ns = nand_get_controller_data(chip);
2112
2113	/* Sanity and correctness checks */
2114	if (!ns->lines.ce) {
2115		NS_ERR("read_buf: chip is disabled\n");
2116		return;
2117	}
2118	if (ns->lines.ale || ns->lines.cle) {
2119		NS_ERR("read_buf: ALE or CLE pin is high\n");
2120		return;
2121	}
2122	if (!(ns->state & STATE_DATAOUT_MASK)) {
2123		NS_WARN("read_buf: unexpected data output cycle, current state is %s\n",
2124			ns_get_state_name(ns->state));
2125		return;
2126	}
2127
2128	if (NS_STATE(ns->state) != STATE_DATAOUT) {
2129		int i;
2130
2131		for (i = 0; i < len; i++)
2132			buf[i] = ns_nand_read_byte(chip);
2133
2134		return;
2135	}
2136
2137	/* Check if these are expected bytes */
2138	if (ns->regs.count + len > ns->regs.num) {
2139		NS_ERR("read_buf: too many bytes to read\n");
2140		ns_switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
2141		return;
2142	}
2143
2144	memcpy(buf, ns->buf.byte + ns->regs.count, len);
2145	ns->regs.count += len;
2146
2147	if (ns->regs.count == ns->regs.num) {
2148		if (NS_STATE(ns->nxstate) == STATE_READY)
2149			ns_switch_state(ns);
2150	}
2151
2152	return;
2153}
2154
2155static int ns_exec_op(struct nand_chip *chip, const struct nand_operation *op,
2156		      bool check_only)
2157{
2158	int i;
2159	unsigned int op_id;
2160	const struct nand_op_instr *instr = NULL;
2161	struct nandsim *ns = nand_get_controller_data(chip);
2162
2163	if (check_only) {
2164		/* The current implementation of nandsim needs to know the
2165		 * ongoing operation when performing the address cycles. This
2166		 * means it cannot make the difference between a regular read
2167		 * and a continuous read. Hence, this hack to manually refuse
2168		 * supporting sequential cached operations.
2169		 */
2170		for (op_id = 0; op_id < op->ninstrs; op_id++) {
2171			instr = &op->instrs[op_id];
2172			if (instr->type == NAND_OP_CMD_INSTR &&
2173			    (instr->ctx.cmd.opcode == NAND_CMD_READCACHEEND ||
2174			     instr->ctx.cmd.opcode == NAND_CMD_READCACHESEQ))
2175				return -EOPNOTSUPP;
2176		}
2177
2178		return 0;
2179	}
2180
2181	ns->lines.ce = 1;
2182
2183	for (op_id = 0; op_id < op->ninstrs; op_id++) {
2184		instr = &op->instrs[op_id];
2185		ns->lines.cle = 0;
2186		ns->lines.ale = 0;
2187
2188		switch (instr->type) {
2189		case NAND_OP_CMD_INSTR:
2190			ns->lines.cle = 1;
2191			ns_nand_write_byte(chip, instr->ctx.cmd.opcode);
2192			break;
2193		case NAND_OP_ADDR_INSTR:
2194			ns->lines.ale = 1;
2195			for (i = 0; i < instr->ctx.addr.naddrs; i++)
2196				ns_nand_write_byte(chip, instr->ctx.addr.addrs[i]);
2197			break;
2198		case NAND_OP_DATA_IN_INSTR:
2199			ns_nand_read_buf(chip, instr->ctx.data.buf.in, instr->ctx.data.len);
2200			break;
2201		case NAND_OP_DATA_OUT_INSTR:
2202			ns_nand_write_buf(chip, instr->ctx.data.buf.out, instr->ctx.data.len);
2203			break;
2204		case NAND_OP_WAITRDY_INSTR:
2205			/* we are always ready */
2206			break;
2207		}
2208	}
2209
2210	return 0;
2211}
2212
2213static int ns_attach_chip(struct nand_chip *chip)
2214{
2215	unsigned int eccsteps, eccbytes;
2216
2217	chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
2218	chip->ecc.algo = bch ? NAND_ECC_ALGO_BCH : NAND_ECC_ALGO_HAMMING;
2219
2220	if (!bch)
2221		return 0;
2222
2223	if (!IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_BCH)) {
2224		NS_ERR("BCH ECC support is disabled\n");
2225		return -EINVAL;
2226	}
2227
2228	/* Use 512-byte ecc blocks */
2229	eccsteps = nsmtd->writesize / 512;
2230	eccbytes = ((bch * 13) + 7) / 8;
2231
2232	/* Do not bother supporting small page devices */
2233	if (nsmtd->oobsize < 64 || !eccsteps) {
2234		NS_ERR("BCH not available on small page devices\n");
2235		return -EINVAL;
2236	}
2237
2238	if (((eccbytes * eccsteps) + 2) > nsmtd->oobsize) {
2239		NS_ERR("Invalid BCH value %u\n", bch);
2240		return -EINVAL;
2241	}
2242
2243	chip->ecc.size = 512;
2244	chip->ecc.strength = bch;
2245	chip->ecc.bytes = eccbytes;
2246
2247	NS_INFO("Using %u-bit/%u bytes BCH ECC\n", bch, chip->ecc.size);
2248
2249	return 0;
2250}
2251
2252static const struct nand_controller_ops ns_controller_ops = {
2253	.attach_chip = ns_attach_chip,
2254	.exec_op = ns_exec_op,
2255};
2256
2257/*
2258 * Module initialization function
2259 */
2260static int __init ns_init_module(void)
2261{
2262	struct list_head *pos, *n;
2263	struct nand_chip *chip;
2264	struct nandsim *ns;
2265	int ret;
2266
2267	if (bus_width != 8 && bus_width != 16) {
2268		NS_ERR("wrong bus width (%d), use only 8 or 16\n", bus_width);
2269		return -EINVAL;
2270	}
2271
2272	ns = kzalloc(sizeof(struct nandsim), GFP_KERNEL);
2273	if (!ns) {
2274		NS_ERR("unable to allocate core structures.\n");
2275		return -ENOMEM;
2276	}
2277	chip	    = &ns->chip;
2278	nsmtd       = nand_to_mtd(chip);
2279	nand_set_controller_data(chip, (void *)ns);
2280
2281	/* The NAND_SKIP_BBTSCAN option is necessary for 'overridesize' */
2282	/* and 'badblocks' parameters to work */
2283	chip->options   |= NAND_SKIP_BBTSCAN;
2284
2285	switch (bbt) {
2286	case 2:
2287		chip->bbt_options |= NAND_BBT_NO_OOB;
2288		fallthrough;
2289	case 1:
2290		chip->bbt_options |= NAND_BBT_USE_FLASH;
2291		fallthrough;
2292	case 0:
2293		break;
2294	default:
2295		NS_ERR("bbt has to be 0..2\n");
2296		ret = -EINVAL;
2297		goto free_ns_struct;
2298	}
2299	/*
2300	 * Perform minimum nandsim structure initialization to handle
2301	 * the initial ID read command correctly
2302	 */
2303	if (id_bytes[6] != 0xFF || id_bytes[7] != 0xFF)
2304		ns->geom.idbytes = 8;
2305	else if (id_bytes[4] != 0xFF || id_bytes[5] != 0xFF)
2306		ns->geom.idbytes = 6;
2307	else if (id_bytes[2] != 0xFF || id_bytes[3] != 0xFF)
2308		ns->geom.idbytes = 4;
2309	else
2310		ns->geom.idbytes = 2;
2311	ns->regs.status = NS_STATUS_OK(ns);
2312	ns->nxstate = STATE_UNKNOWN;
2313	ns->options |= OPT_PAGE512; /* temporary value */
2314	memcpy(ns->ids, id_bytes, sizeof(ns->ids));
2315	if (bus_width == 16) {
2316		ns->busw = 16;
2317		chip->options |= NAND_BUSWIDTH_16;
2318	}
2319
2320	nsmtd->owner = THIS_MODULE;
2321
2322	ret = ns_parse_weakblocks();
2323	if (ret)
2324		goto free_ns_struct;
2325
2326	ret = ns_parse_weakpages();
2327	if (ret)
2328		goto free_wb_list;
2329
2330	ret = ns_parse_gravepages();
2331	if (ret)
2332		goto free_wp_list;
2333
2334	nand_controller_init(&ns->base);
2335	ns->base.ops = &ns_controller_ops;
2336	chip->controller = &ns->base;
2337
2338	ret = nand_scan(chip, 1);
2339	if (ret) {
2340		NS_ERR("Could not scan NAND Simulator device\n");
2341		goto free_gp_list;
2342	}
2343
2344	if (overridesize) {
2345		uint64_t new_size = (uint64_t)nsmtd->erasesize << overridesize;
2346		struct nand_memory_organization *memorg;
2347		u64 targetsize;
2348
2349		memorg = nanddev_get_memorg(&chip->base);
2350
2351		if (new_size >> overridesize != nsmtd->erasesize) {
2352			NS_ERR("overridesize is too big\n");
2353			ret = -EINVAL;
2354			goto cleanup_nand;
2355		}
2356
2357		/* N.B. This relies on nand_scan not doing anything with the size before we change it */
2358		nsmtd->size = new_size;
2359		memorg->eraseblocks_per_lun = 1 << overridesize;
2360		targetsize = nanddev_target_size(&chip->base);
2361		chip->chip_shift = ffs(nsmtd->erasesize) + overridesize - 1;
2362		chip->pagemask = (targetsize >> chip->page_shift) - 1;
2363	}
2364
2365	ret = ns_setup_wear_reporting(nsmtd);
2366	if (ret)
2367		goto cleanup_nand;
2368
2369	ret = ns_init(nsmtd);
2370	if (ret)
2371		goto free_ebw;
2372
2373	ret = nand_create_bbt(chip);
2374	if (ret)
2375		goto free_ns_object;
2376
2377	ret = ns_parse_badblocks(ns, nsmtd);
2378	if (ret)
2379		goto free_ns_object;
2380
2381	/* Register NAND partitions */
2382	ret = mtd_device_register(nsmtd, &ns->partitions[0], ns->nbparts);
2383	if (ret)
2384		goto free_ns_object;
2385
2386	ret = ns_debugfs_create(ns);
2387	if (ret)
2388		goto unregister_mtd;
2389
2390        return 0;
2391
2392unregister_mtd:
2393	WARN_ON(mtd_device_unregister(nsmtd));
2394free_ns_object:
2395	ns_free(ns);
2396free_ebw:
2397	kfree(erase_block_wear);
2398cleanup_nand:
2399	nand_cleanup(chip);
2400free_gp_list:
2401	list_for_each_safe(pos, n, &grave_pages) {
2402		list_del(pos);
2403		kfree(list_entry(pos, struct grave_page, list));
2404	}
2405free_wp_list:
2406	list_for_each_safe(pos, n, &weak_pages) {
2407		list_del(pos);
2408		kfree(list_entry(pos, struct weak_page, list));
2409	}
2410free_wb_list:
2411	list_for_each_safe(pos, n, &weak_blocks) {
2412		list_del(pos);
2413		kfree(list_entry(pos, struct weak_block, list));
2414	}
2415free_ns_struct:
2416	kfree(ns);
2417
2418	return ret;
2419}
2420
2421module_init(ns_init_module);
2422
2423/*
2424 * Module clean-up function
2425 */
2426static void __exit ns_cleanup_module(void)
2427{
2428	struct nand_chip *chip = mtd_to_nand(nsmtd);
2429	struct nandsim *ns = nand_get_controller_data(chip);
2430	struct list_head *pos, *n;
2431
2432	ns_debugfs_remove(ns);
2433	WARN_ON(mtd_device_unregister(nsmtd));
2434	ns_free(ns);
2435	kfree(erase_block_wear);
2436	nand_cleanup(chip);
2437
2438	list_for_each_safe(pos, n, &grave_pages) {
2439		list_del(pos);
2440		kfree(list_entry(pos, struct grave_page, list));
2441	}
2442
2443	list_for_each_safe(pos, n, &weak_pages) {
2444		list_del(pos);
2445		kfree(list_entry(pos, struct weak_page, list));
2446	}
2447
2448	list_for_each_safe(pos, n, &weak_blocks) {
2449		list_del(pos);
2450		kfree(list_entry(pos, struct weak_block, list));
2451	}
2452
2453	kfree(ns);
2454}
2455
2456module_exit(ns_cleanup_module);
2457
2458MODULE_LICENSE ("GPL");
2459MODULE_AUTHOR ("Artem B. Bityuckiy");
2460MODULE_DESCRIPTION ("The NAND flash simulator");
2461