summaryrefslogtreecommitdiffstats
path: root/fs/yaffs2/yaffs_tagscompat.c
blob: 9ac5896da37713d51875c8f9bd23b6d4e434fa88 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
/*
 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
 *
 * Copyright (C) 2002-2011 Aleph One Ltd.
 *   for Toby Churchill Ltd and Brightstar Engineering
 *
 * Created by Charles Manning <charles@aleph1.co.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include "yaffs_guts.h"
#include "yaffs_tagscompat.h"
#include "yaffs_ecc.h"
#include "yaffs_getblockinfo.h"
#include "yaffs_trace.h"

static void yaffs_handle_rd_data_error(struct yaffs_dev *dev, int nand_chunk);


/********** Tags ECC calculations  *********/

void yaffs_calc_ecc(const u8 *data, struct yaffs_spare *spare)
{
	yaffs_ecc_calc(data, spare->ecc1);
	yaffs_ecc_calc(&data[256], spare->ecc2);
}

void yaffs_calc_tags_ecc(struct yaffs_tags *tags)
{
	/* Calculate an ecc */
	unsigned char *b = ((union yaffs_tags_union *)tags)->as_bytes;
	unsigned i, j;
	unsigned ecc = 0;
	unsigned bit = 0;

	tags->ecc = 0;

	for (i = 0; i < 8; i++) {
		for (j = 1; j & 0xff; j <<= 1) {
			bit++;
			if (b[i] & j)
				ecc ^= bit;
		}
	}
	tags->ecc = ecc;
}

int yaffs_check_tags_ecc(struct yaffs_tags *tags)
{
	unsigned ecc = tags->ecc;

	yaffs_calc_tags_ecc(tags);

	ecc ^= tags->ecc;

	if (ecc && ecc <= 64) {
		/* TODO: Handle the failure better. Retire? */
		unsigned char *b = ((union yaffs_tags_union *)tags)->as_bytes;

		ecc--;

		b[ecc / 8] ^= (1 << (ecc & 7));

		/* Now recvalc the ecc */
		yaffs_calc_tags_ecc(tags);

		return 1;	/* recovered error */
	} else if (ecc) {
		/* Wierd ecc failure value */
		/* TODO Need to do somethiong here */
		return -1;	/* unrecovered error */
	}
	return 0;
}

/********** Tags **********/

static void yaffs_load_tags_to_spare(struct yaffs_spare *spare_ptr,
				     struct yaffs_tags *tags_ptr)
{
	union yaffs_tags_union *tu = (union yaffs_tags_union *)tags_ptr;

	yaffs_calc_tags_ecc(tags_ptr);

	spare_ptr->tb0 = tu->as_bytes[0];
	spare_ptr->tb1 = tu->as_bytes[1];
	spare_ptr->tb2 = tu->as_bytes[2];
	spare_ptr->tb3 = tu->as_bytes[3];
	spare_ptr->tb4 = tu->as_bytes[4];
	spare_ptr->tb5 = tu->as_bytes[5];
	spare_ptr->tb6 = tu->as_bytes[6];
	spare_ptr->tb7 = tu->as_bytes[7];
}

static void yaffs_get_tags_from_spare(struct yaffs_dev *dev,
				      struct yaffs_spare *spare_ptr,
				      struct yaffs_tags *tags_ptr)
{
	union yaffs_tags_union *tu = (union yaffs_tags_union *)tags_ptr;
	int result;

	tu->as_bytes[0] = spare_ptr->tb0;
	tu->as_bytes[1] = spare_ptr->tb1;
	tu->as_bytes[2] = spare_ptr->tb2;
	tu->as_bytes[3] = spare_ptr->tb3;
	tu->as_bytes[4] = spare_ptr->tb4;
	tu->as_bytes[5] = spare_ptr->tb5;
	tu->as_bytes[6] = spare_ptr->tb6;
	tu->as_bytes[7] = spare_ptr->tb7;

	result = yaffs_check_tags_ecc(tags_ptr);
	if (result > 0)
		dev->n_tags_ecc_fixed++;
	else if (result < 0)
		dev->n_tags_ecc_unfixed++;
}

static void yaffs_spare_init(struct yaffs_spare *spare)
{
	memset(spare, 0xff, sizeof(struct yaffs_spare));
}

static int yaffs_wr_nand(struct yaffs_dev *dev,
			 int nand_chunk, const u8 *data,
			 struct yaffs_spare *spare)
{
	if (nand_chunk < dev->param.start_block * dev->param.chunks_per_block) {
		yaffs_trace(YAFFS_TRACE_ERROR,
			"**>> yaffs chunk %d is not valid",
			nand_chunk);
		return YAFFS_FAIL;
	}

	return dev->param.write_chunk_fn(dev, nand_chunk, data, spare);
}

static int yaffs_rd_chunk_nand(struct yaffs_dev *dev,
			       int nand_chunk,
			       u8 *data,
			       struct yaffs_spare *spare,
			       enum yaffs_ecc_result *ecc_result,
			       int correct_errors)
{
	int ret_val;
	struct yaffs_spare local_spare;

	if (!spare) {
		/* If we don't have a real spare, then we use a local one. */
		/* Need this for the calculation of the ecc */
		spare = &local_spare;
	}

	if (!dev->param.use_nand_ecc) {
		ret_val =
		    dev->param.read_chunk_fn(dev, nand_chunk, data, spare);
		if (data && correct_errors) {
			/* Do ECC correction */
			/* Todo handle any errors */
			int ecc_result1, ecc_result2;
			u8 calc_ecc[3];

			yaffs_ecc_calc(data, calc_ecc);
			ecc_result1 =
			    yaffs_ecc_correct(data, spare->ecc1, calc_ecc);
			yaffs_ecc_calc(&data[256], calc_ecc);
			ecc_result2 =
			    yaffs_ecc_correct(&data[256], spare->ecc2,
					      calc_ecc);

			if (ecc_result1 > 0) {
				yaffs_trace(YAFFS_TRACE_ERROR,
					"**>>yaffs ecc error fix performed on chunk %d:0",
					nand_chunk);
				dev->n_ecc_fixed++;
			} else if (ecc_result1 < 0) {
				yaffs_trace(YAFFS_TRACE_ERROR,
					"**>>yaffs ecc error unfixed on chunk %d:0",
					nand_chunk);
				dev->n_ecc_unfixed++;
			}

			if (ecc_result2 > 0) {
				yaffs_trace(YAFFS_TRACE_ERROR,
					"**>>yaffs ecc error fix performed on chunk %d:1",
					nand_chunk);
				dev->n_ecc_fixed++;
			} else if (ecc_result2 < 0) {
				yaffs_trace(YAFFS_TRACE_ERROR,
					"**>>yaffs ecc error unfixed on chunk %d:1",
					nand_chunk);
				dev->n_ecc_unfixed++;
			}

			if (ecc_result1 || ecc_result2) {
				/* We had a data problem on this page */
				yaffs_handle_rd_data_error(dev, nand_chunk);
			}

			if (ecc_result1 < 0 || ecc_result2 < 0)
				*ecc_result = YAFFS_ECC_RESULT_UNFIXED;
			else if (ecc_result1 > 0 || ecc_result2 > 0)
				*ecc_result = YAFFS_ECC_RESULT_FIXED;
			else
				*ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
		}
	} else {
		/* Must allocate enough memory for spare+2*sizeof(int) */
		/* for ecc results from device. */
		struct yaffs_nand_spare nspare;

		memset(&nspare, 0, sizeof(nspare));

		ret_val = dev->param.read_chunk_fn(dev, nand_chunk, data,
						   (struct yaffs_spare *)
						   &nspare);
		memcpy(spare, &nspare, sizeof(struct yaffs_spare));
		if (data && correct_errors) {
			if (nspare.eccres1 > 0) {
				yaffs_trace(YAFFS_TRACE_ERROR,
					"**>>mtd ecc error fix performed on chunk %d:0",
					nand_chunk);
			} else if (nspare.eccres1 < 0) {
				yaffs_trace(YAFFS_TRACE_ERROR,
					"**>>mtd ecc error unfixed on chunk %d:0",
					nand_chunk);
			}

			if (nspare.eccres2 > 0) {
				yaffs_trace(YAFFS_TRACE_ERROR,
					"**>>mtd ecc error fix performed on chunk %d:1",
					nand_chunk);
			} else if (nspare.eccres2 < 0) {
				yaffs_trace(YAFFS_TRACE_ERROR,
					"**>>mtd ecc error unfixed on chunk %d:1",
					nand_chunk);
			}

			if (nspare.eccres1 || nspare.eccres2) {
				/* We had a data problem on this page */
				yaffs_handle_rd_data_error(dev, nand_chunk);
			}

			if (nspare.eccres1 < 0 || nspare.eccres2 < 0)
				*ecc_result = YAFFS_ECC_RESULT_UNFIXED;
			else if (nspare.eccres1 > 0 || nspare.eccres2 > 0)
				*ecc_result = YAFFS_ECC_RESULT_FIXED;
			else
				*ecc_result = YAFFS_ECC_RESULT_NO_ERROR;

		}
	}
	return ret_val;
}

/*
 * Functions for robustisizing
 */

static void yaffs_handle_rd_data_error(struct yaffs_dev *dev, int nand_chunk)
{
	int flash_block = nand_chunk / dev->param.chunks_per_block;

	/* Mark the block for retirement */
	yaffs_get_block_info(dev, flash_block + dev->block_offset)->
		needs_retiring = 1;
	yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
		"**>>Block %d marked for retirement",
		flash_block);

	/* TODO:
	 * Just do a garbage collection on the affected block
	 * then retire the block
	 * NB recursion
	 */
}

int yaffs_tags_compat_wr(struct yaffs_dev *dev,
			 int nand_chunk,
			 const u8 *data, const struct yaffs_ext_tags *ext_tags)
{
	struct yaffs_spare spare;
	struct yaffs_tags tags;

	yaffs_spare_init(&spare);

	if (ext_tags->is_deleted)
		spare.page_status = 0;
	else {
		tags.obj_id = ext_tags->obj_id;
		tags.chunk_id = ext_tags->chunk_id;

		tags.n_bytes_lsb = ext_tags->n_bytes & (1024 - 1);

		if (dev->data_bytes_per_chunk >= 1024)
			tags.n_bytes_msb = (ext_tags->n_bytes >> 10) & 3;
		else
			tags.n_bytes_msb = 3;

		tags.serial_number = ext_tags->serial_number;

		if (!dev->param.use_nand_ecc && data)
			yaffs_calc_ecc(data, &spare);

		yaffs_load_tags_to_spare(&spare, &tags);
	}
	return yaffs_wr_nand(dev, nand_chunk, data, &spare);
}

int yaffs_tags_compat_rd(struct yaffs_dev *dev,
			 int nand_chunk,
			 u8 *data, struct yaffs_ext_tags *ext_tags)
{
	struct yaffs_spare spare;
	struct yaffs_tags tags;
	enum yaffs_ecc_result ecc_result = YAFFS_ECC_RESULT_UNKNOWN;
	static struct yaffs_spare spare_ff;
	static int init;
	int deleted;

	if (!init) {
		memset(&spare_ff, 0xff, sizeof(spare_ff));
		init = 1;
	}

	if (!yaffs_rd_chunk_nand(dev, nand_chunk,
					data, &spare, &ecc_result, 1))
		return YAFFS_FAIL;

	/* ext_tags may be NULL */
	if (!ext_tags)
		return YAFFS_OK;

	deleted = (hweight8(spare.page_status) < 7) ? 1 : 0;

	ext_tags->is_deleted = deleted;
	ext_tags->ecc_result = ecc_result;
	ext_tags->block_bad = 0;	/* We're reading it */
	/* therefore it is not a bad block */
	ext_tags->chunk_used =
		memcmp(&spare_ff, &spare, sizeof(spare_ff)) ? 1 : 0;

	if (ext_tags->chunk_used) {
		yaffs_get_tags_from_spare(dev, &spare, &tags);
		ext_tags->obj_id = tags.obj_id;
		ext_tags->chunk_id = tags.chunk_id;
		ext_tags->n_bytes = tags.n_bytes_lsb;

		if (dev->data_bytes_per_chunk >= 1024)
			ext_tags->n_bytes |=
				(((unsigned)tags.n_bytes_msb) << 10);

		ext_tags->serial_number = tags.serial_number;
	}

	return YAFFS_OK;
}

int yaffs_tags_compat_mark_bad(struct yaffs_dev *dev, int flash_block)
{
	struct yaffs_spare spare;

	memset(&spare, 0xff, sizeof(struct yaffs_spare));

	spare.block_status = 'Y';

	yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block, NULL,
		      &spare);
	yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block + 1,
		      NULL, &spare);

	return YAFFS_OK;
}

int yaffs_tags_compat_query_block(struct yaffs_dev *dev,
				  int block_no,
				  enum yaffs_block_state *state,
				  u32 *seq_number)
{
	struct yaffs_spare spare0, spare1;
	static struct yaffs_spare spare_ff;
	static int init;
	enum yaffs_ecc_result dummy;

	if (!init) {
		memset(&spare_ff, 0xff, sizeof(spare_ff));
		init = 1;
	}

	*seq_number = 0;

	yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block, NULL,
			    &spare0, &dummy, 1);
	yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block + 1,
			    NULL, &spare1, &dummy, 1);

	if (hweight8(spare0.block_status & spare1.block_status) < 7)
		*state = YAFFS_BLOCK_STATE_DEAD;
	else if (memcmp(&spare_ff, &spare0, sizeof(spare_ff)) == 0)
		*state = YAFFS_BLOCK_STATE_EMPTY;
	else
		*state = YAFFS_BLOCK_STATE_NEEDS_SCAN;

	return YAFFS_OK;
}
OpenPOWER on IntegriCloud