hyperv: Remove recv_pkt_list and lock
[linux/fpc-iii.git] / drivers / mtd / nand / nand_ecc.c
blob053c9a2d47c3d02daca5589f622bb0e083c67afa
1 /*
2 * This file contains an ECC algorithm that detects and corrects 1 bit
3 * errors in a 256 byte block of data.
5 * drivers/mtd/nand/nand_ecc.c
7 * Copyright © 2008 Koninklijke Philips Electronics NV.
8 * Author: Frans Meulenbroeks
10 * Completely replaces the previous ECC implementation which was written by:
11 * Steven J. Hill (sjhill@realitydiluted.com)
12 * Thomas Gleixner (tglx@linutronix.de)
14 * Information on how this algorithm works and how it was developed
15 * can be found in Documentation/mtd/nand_ecc.txt
17 * This file is free software; you can redistribute it and/or modify it
18 * under the terms of the GNU General Public License as published by the
19 * Free Software Foundation; either version 2 or (at your option) any
20 * later version.
22 * This file is distributed in the hope that it will be useful, but WITHOUT
23 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
24 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
25 * for more details.
27 * You should have received a copy of the GNU General Public License along
28 * with this file; if not, write to the Free Software Foundation, Inc.,
29 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
34 * The STANDALONE macro is useful when running the code outside the kernel
35 * e.g. when running the code in a testbed or a benchmark program.
36 * When STANDALONE is used, the module related macros are commented out
37 * as well as the linux include files.
38 * Instead a private definition of mtd_info is given to satisfy the compiler
39 * (the code does not use mtd_info, so the code does not care)
41 #ifndef STANDALONE
42 #include <linux/types.h>
43 #include <linux/kernel.h>
44 #include <linux/module.h>
45 #include <linux/mtd/mtd.h>
46 #include <linux/mtd/nand.h>
47 #include <linux/mtd/nand_ecc.h>
48 #include <asm/byteorder.h>
49 #else
50 #include <stdint.h>
51 struct mtd_info;
52 #define EXPORT_SYMBOL(x) /* x */
54 #define MODULE_LICENSE(x) /* x */
55 #define MODULE_AUTHOR(x) /* x */
56 #define MODULE_DESCRIPTION(x) /* x */
58 #define pr_err printf
59 #endif
62 * invparity is a 256 byte table that contains the odd parity
63 * for each byte. So if the number of bits in a byte is even,
64 * the array element is 1, and when the number of bits is odd
65 * the array eleemnt is 0.
67 static const char invparity[256] = {
68 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
69 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
70 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
71 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
72 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
73 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
74 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
75 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
76 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
77 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
78 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
79 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
80 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
81 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
82 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
83 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
87 * bitsperbyte contains the number of bits per byte
88 * this is only used for testing and repairing parity
89 * (a precalculated value slightly improves performance)
91 static const char bitsperbyte[256] = {
92 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
93 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
94 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
95 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
96 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
97 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
98 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
99 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
100 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
101 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
102 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
103 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
104 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
105 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
106 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
107 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
111 * addressbits is a lookup table to filter out the bits from the xor-ed
112 * ECC data that identify the faulty location.
113 * this is only used for repairing parity
114 * see the comments in nand_correct_data for more details
116 static const char addressbits[256] = {
117 0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x01,
118 0x02, 0x02, 0x03, 0x03, 0x02, 0x02, 0x03, 0x03,
119 0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x01,
120 0x02, 0x02, 0x03, 0x03, 0x02, 0x02, 0x03, 0x03,
121 0x04, 0x04, 0x05, 0x05, 0x04, 0x04, 0x05, 0x05,
122 0x06, 0x06, 0x07, 0x07, 0x06, 0x06, 0x07, 0x07,
123 0x04, 0x04, 0x05, 0x05, 0x04, 0x04, 0x05, 0x05,
124 0x06, 0x06, 0x07, 0x07, 0x06, 0x06, 0x07, 0x07,
125 0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x01,
126 0x02, 0x02, 0x03, 0x03, 0x02, 0x02, 0x03, 0x03,
127 0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x01,
128 0x02, 0x02, 0x03, 0x03, 0x02, 0x02, 0x03, 0x03,
129 0x04, 0x04, 0x05, 0x05, 0x04, 0x04, 0x05, 0x05,
130 0x06, 0x06, 0x07, 0x07, 0x06, 0x06, 0x07, 0x07,
131 0x04, 0x04, 0x05, 0x05, 0x04, 0x04, 0x05, 0x05,
132 0x06, 0x06, 0x07, 0x07, 0x06, 0x06, 0x07, 0x07,
133 0x08, 0x08, 0x09, 0x09, 0x08, 0x08, 0x09, 0x09,
134 0x0a, 0x0a, 0x0b, 0x0b, 0x0a, 0x0a, 0x0b, 0x0b,
135 0x08, 0x08, 0x09, 0x09, 0x08, 0x08, 0x09, 0x09,
136 0x0a, 0x0a, 0x0b, 0x0b, 0x0a, 0x0a, 0x0b, 0x0b,
137 0x0c, 0x0c, 0x0d, 0x0d, 0x0c, 0x0c, 0x0d, 0x0d,
138 0x0e, 0x0e, 0x0f, 0x0f, 0x0e, 0x0e, 0x0f, 0x0f,
139 0x0c, 0x0c, 0x0d, 0x0d, 0x0c, 0x0c, 0x0d, 0x0d,
140 0x0e, 0x0e, 0x0f, 0x0f, 0x0e, 0x0e, 0x0f, 0x0f,
141 0x08, 0x08, 0x09, 0x09, 0x08, 0x08, 0x09, 0x09,
142 0x0a, 0x0a, 0x0b, 0x0b, 0x0a, 0x0a, 0x0b, 0x0b,
143 0x08, 0x08, 0x09, 0x09, 0x08, 0x08, 0x09, 0x09,
144 0x0a, 0x0a, 0x0b, 0x0b, 0x0a, 0x0a, 0x0b, 0x0b,
145 0x0c, 0x0c, 0x0d, 0x0d, 0x0c, 0x0c, 0x0d, 0x0d,
146 0x0e, 0x0e, 0x0f, 0x0f, 0x0e, 0x0e, 0x0f, 0x0f,
147 0x0c, 0x0c, 0x0d, 0x0d, 0x0c, 0x0c, 0x0d, 0x0d,
148 0x0e, 0x0e, 0x0f, 0x0f, 0x0e, 0x0e, 0x0f, 0x0f
152 * __nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
153 * block
154 * @buf: input buffer with raw data
155 * @eccsize: data bytes per ECC step (256 or 512)
156 * @code: output buffer with ECC
158 void __nand_calculate_ecc(const unsigned char *buf, unsigned int eccsize,
159 unsigned char *code)
161 int i;
162 const uint32_t *bp = (uint32_t *)buf;
163 /* 256 or 512 bytes/ecc */
164 const uint32_t eccsize_mult = eccsize >> 8;
165 uint32_t cur; /* current value in buffer */
166 /* rp0..rp15..rp17 are the various accumulated parities (per byte) */
167 uint32_t rp0, rp1, rp2, rp3, rp4, rp5, rp6, rp7;
168 uint32_t rp8, rp9, rp10, rp11, rp12, rp13, rp14, rp15, rp16;
169 uint32_t uninitialized_var(rp17); /* to make compiler happy */
170 uint32_t par; /* the cumulative parity for all data */
171 uint32_t tmppar; /* the cumulative parity for this iteration;
172 for rp12, rp14 and rp16 at the end of the
173 loop */
175 par = 0;
176 rp4 = 0;
177 rp6 = 0;
178 rp8 = 0;
179 rp10 = 0;
180 rp12 = 0;
181 rp14 = 0;
182 rp16 = 0;
185 * The loop is unrolled a number of times;
186 * This avoids if statements to decide on which rp value to update
187 * Also we process the data by longwords.
188 * Note: passing unaligned data might give a performance penalty.
189 * It is assumed that the buffers are aligned.
190 * tmppar is the cumulative sum of this iteration.
191 * needed for calculating rp12, rp14, rp16 and par
192 * also used as a performance improvement for rp6, rp8 and rp10
194 for (i = 0; i < eccsize_mult << 2; i++) {
195 cur = *bp++;
196 tmppar = cur;
197 rp4 ^= cur;
198 cur = *bp++;
199 tmppar ^= cur;
200 rp6 ^= tmppar;
201 cur = *bp++;
202 tmppar ^= cur;
203 rp4 ^= cur;
204 cur = *bp++;
205 tmppar ^= cur;
206 rp8 ^= tmppar;
208 cur = *bp++;
209 tmppar ^= cur;
210 rp4 ^= cur;
211 rp6 ^= cur;
212 cur = *bp++;
213 tmppar ^= cur;
214 rp6 ^= cur;
215 cur = *bp++;
216 tmppar ^= cur;
217 rp4 ^= cur;
218 cur = *bp++;
219 tmppar ^= cur;
220 rp10 ^= tmppar;
222 cur = *bp++;
223 tmppar ^= cur;
224 rp4 ^= cur;
225 rp6 ^= cur;
226 rp8 ^= cur;
227 cur = *bp++;
228 tmppar ^= cur;
229 rp6 ^= cur;
230 rp8 ^= cur;
231 cur = *bp++;
232 tmppar ^= cur;
233 rp4 ^= cur;
234 rp8 ^= cur;
235 cur = *bp++;
236 tmppar ^= cur;
237 rp8 ^= cur;
239 cur = *bp++;
240 tmppar ^= cur;
241 rp4 ^= cur;
242 rp6 ^= cur;
243 cur = *bp++;
244 tmppar ^= cur;
245 rp6 ^= cur;
246 cur = *bp++;
247 tmppar ^= cur;
248 rp4 ^= cur;
249 cur = *bp++;
250 tmppar ^= cur;
252 par ^= tmppar;
253 if ((i & 0x1) == 0)
254 rp12 ^= tmppar;
255 if ((i & 0x2) == 0)
256 rp14 ^= tmppar;
257 if (eccsize_mult == 2 && (i & 0x4) == 0)
258 rp16 ^= tmppar;
262 * handle the fact that we use longword operations
263 * we'll bring rp4..rp14..rp16 back to single byte entities by
264 * shifting and xoring first fold the upper and lower 16 bits,
265 * then the upper and lower 8 bits.
267 rp4 ^= (rp4 >> 16);
268 rp4 ^= (rp4 >> 8);
269 rp4 &= 0xff;
270 rp6 ^= (rp6 >> 16);
271 rp6 ^= (rp6 >> 8);
272 rp6 &= 0xff;
273 rp8 ^= (rp8 >> 16);
274 rp8 ^= (rp8 >> 8);
275 rp8 &= 0xff;
276 rp10 ^= (rp10 >> 16);
277 rp10 ^= (rp10 >> 8);
278 rp10 &= 0xff;
279 rp12 ^= (rp12 >> 16);
280 rp12 ^= (rp12 >> 8);
281 rp12 &= 0xff;
282 rp14 ^= (rp14 >> 16);
283 rp14 ^= (rp14 >> 8);
284 rp14 &= 0xff;
285 if (eccsize_mult == 2) {
286 rp16 ^= (rp16 >> 16);
287 rp16 ^= (rp16 >> 8);
288 rp16 &= 0xff;
292 * we also need to calculate the row parity for rp0..rp3
293 * This is present in par, because par is now
294 * rp3 rp3 rp2 rp2 in little endian and
295 * rp2 rp2 rp3 rp3 in big endian
296 * as well as
297 * rp1 rp0 rp1 rp0 in little endian and
298 * rp0 rp1 rp0 rp1 in big endian
299 * First calculate rp2 and rp3
301 #ifdef __BIG_ENDIAN
302 rp2 = (par >> 16);
303 rp2 ^= (rp2 >> 8);
304 rp2 &= 0xff;
305 rp3 = par & 0xffff;
306 rp3 ^= (rp3 >> 8);
307 rp3 &= 0xff;
308 #else
309 rp3 = (par >> 16);
310 rp3 ^= (rp3 >> 8);
311 rp3 &= 0xff;
312 rp2 = par & 0xffff;
313 rp2 ^= (rp2 >> 8);
314 rp2 &= 0xff;
315 #endif
317 /* reduce par to 16 bits then calculate rp1 and rp0 */
318 par ^= (par >> 16);
319 #ifdef __BIG_ENDIAN
320 rp0 = (par >> 8) & 0xff;
321 rp1 = (par & 0xff);
322 #else
323 rp1 = (par >> 8) & 0xff;
324 rp0 = (par & 0xff);
325 #endif
327 /* finally reduce par to 8 bits */
328 par ^= (par >> 8);
329 par &= 0xff;
332 * and calculate rp5..rp15..rp17
333 * note that par = rp4 ^ rp5 and due to the commutative property
334 * of the ^ operator we can say:
335 * rp5 = (par ^ rp4);
336 * The & 0xff seems superfluous, but benchmarking learned that
337 * leaving it out gives slightly worse results. No idea why, probably
338 * it has to do with the way the pipeline in pentium is organized.
340 rp5 = (par ^ rp4) & 0xff;
341 rp7 = (par ^ rp6) & 0xff;
342 rp9 = (par ^ rp8) & 0xff;
343 rp11 = (par ^ rp10) & 0xff;
344 rp13 = (par ^ rp12) & 0xff;
345 rp15 = (par ^ rp14) & 0xff;
346 if (eccsize_mult == 2)
347 rp17 = (par ^ rp16) & 0xff;
350 * Finally calculate the ECC bits.
351 * Again here it might seem that there are performance optimisations
352 * possible, but benchmarks showed that on the system this is developed
353 * the code below is the fastest
355 #ifdef CONFIG_MTD_NAND_ECC_SMC
356 code[0] =
357 (invparity[rp7] << 7) |
358 (invparity[rp6] << 6) |
359 (invparity[rp5] << 5) |
360 (invparity[rp4] << 4) |
361 (invparity[rp3] << 3) |
362 (invparity[rp2] << 2) |
363 (invparity[rp1] << 1) |
364 (invparity[rp0]);
365 code[1] =
366 (invparity[rp15] << 7) |
367 (invparity[rp14] << 6) |
368 (invparity[rp13] << 5) |
369 (invparity[rp12] << 4) |
370 (invparity[rp11] << 3) |
371 (invparity[rp10] << 2) |
372 (invparity[rp9] << 1) |
373 (invparity[rp8]);
374 #else
375 code[1] =
376 (invparity[rp7] << 7) |
377 (invparity[rp6] << 6) |
378 (invparity[rp5] << 5) |
379 (invparity[rp4] << 4) |
380 (invparity[rp3] << 3) |
381 (invparity[rp2] << 2) |
382 (invparity[rp1] << 1) |
383 (invparity[rp0]);
384 code[0] =
385 (invparity[rp15] << 7) |
386 (invparity[rp14] << 6) |
387 (invparity[rp13] << 5) |
388 (invparity[rp12] << 4) |
389 (invparity[rp11] << 3) |
390 (invparity[rp10] << 2) |
391 (invparity[rp9] << 1) |
392 (invparity[rp8]);
393 #endif
394 if (eccsize_mult == 1)
395 code[2] =
396 (invparity[par & 0xf0] << 7) |
397 (invparity[par & 0x0f] << 6) |
398 (invparity[par & 0xcc] << 5) |
399 (invparity[par & 0x33] << 4) |
400 (invparity[par & 0xaa] << 3) |
401 (invparity[par & 0x55] << 2) |
403 else
404 code[2] =
405 (invparity[par & 0xf0] << 7) |
406 (invparity[par & 0x0f] << 6) |
407 (invparity[par & 0xcc] << 5) |
408 (invparity[par & 0x33] << 4) |
409 (invparity[par & 0xaa] << 3) |
410 (invparity[par & 0x55] << 2) |
411 (invparity[rp17] << 1) |
412 (invparity[rp16] << 0);
414 EXPORT_SYMBOL(__nand_calculate_ecc);
417 * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
418 * block
419 * @mtd: MTD block structure
420 * @buf: input buffer with raw data
421 * @code: output buffer with ECC
423 int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
424 unsigned char *code)
426 __nand_calculate_ecc(buf,
427 ((struct nand_chip *)mtd->priv)->ecc.size, code);
429 return 0;
431 EXPORT_SYMBOL(nand_calculate_ecc);
434 * __nand_correct_data - [NAND Interface] Detect and correct bit error(s)
435 * @buf: raw data read from the chip
436 * @read_ecc: ECC from the chip
437 * @calc_ecc: the ECC calculated from raw data
438 * @eccsize: data bytes per ECC step (256 or 512)
440 * Detect and correct a 1 bit error for eccsize byte block
442 int __nand_correct_data(unsigned char *buf,
443 unsigned char *read_ecc, unsigned char *calc_ecc,
444 unsigned int eccsize)
446 unsigned char b0, b1, b2, bit_addr;
447 unsigned int byte_addr;
448 /* 256 or 512 bytes/ecc */
449 const uint32_t eccsize_mult = eccsize >> 8;
452 * b0 to b2 indicate which bit is faulty (if any)
453 * we might need the xor result more than once,
454 * so keep them in a local var
456 #ifdef CONFIG_MTD_NAND_ECC_SMC
457 b0 = read_ecc[0] ^ calc_ecc[0];
458 b1 = read_ecc[1] ^ calc_ecc[1];
459 #else
460 b0 = read_ecc[1] ^ calc_ecc[1];
461 b1 = read_ecc[0] ^ calc_ecc[0];
462 #endif
463 b2 = read_ecc[2] ^ calc_ecc[2];
465 /* check if there are any bitfaults */
467 /* repeated if statements are slightly more efficient than switch ... */
468 /* ordered in order of likelihood */
470 if ((b0 | b1 | b2) == 0)
471 return 0; /* no error */
473 if ((((b0 ^ (b0 >> 1)) & 0x55) == 0x55) &&
474 (((b1 ^ (b1 >> 1)) & 0x55) == 0x55) &&
475 ((eccsize_mult == 1 && ((b2 ^ (b2 >> 1)) & 0x54) == 0x54) ||
476 (eccsize_mult == 2 && ((b2 ^ (b2 >> 1)) & 0x55) == 0x55))) {
477 /* single bit error */
479 * rp17/rp15/13/11/9/7/5/3/1 indicate which byte is the faulty
480 * byte, cp 5/3/1 indicate the faulty bit.
481 * A lookup table (called addressbits) is used to filter
482 * the bits from the byte they are in.
483 * A marginal optimisation is possible by having three
484 * different lookup tables.
485 * One as we have now (for b0), one for b2
486 * (that would avoid the >> 1), and one for b1 (with all values
487 * << 4). However it was felt that introducing two more tables
488 * hardly justify the gain.
490 * The b2 shift is there to get rid of the lowest two bits.
491 * We could also do addressbits[b2] >> 1 but for the
492 * performance it does not make any difference
494 if (eccsize_mult == 1)
495 byte_addr = (addressbits[b1] << 4) + addressbits[b0];
496 else
497 byte_addr = (addressbits[b2 & 0x3] << 8) +
498 (addressbits[b1] << 4) + addressbits[b0];
499 bit_addr = addressbits[b2 >> 2];
500 /* flip the bit */
501 buf[byte_addr] ^= (1 << bit_addr);
502 return 1;
505 /* count nr of bits; use table lookup, faster than calculating it */
506 if ((bitsperbyte[b0] + bitsperbyte[b1] + bitsperbyte[b2]) == 1)
507 return 1; /* error in ECC data; no action needed */
509 pr_err("%s: uncorrectable ECC error", __func__);
510 return -1;
512 EXPORT_SYMBOL(__nand_correct_data);
515 * nand_correct_data - [NAND Interface] Detect and correct bit error(s)
516 * @mtd: MTD block structure
517 * @buf: raw data read from the chip
518 * @read_ecc: ECC from the chip
519 * @calc_ecc: the ECC calculated from raw data
521 * Detect and correct a 1 bit error for 256/512 byte block
523 int nand_correct_data(struct mtd_info *mtd, unsigned char *buf,
524 unsigned char *read_ecc, unsigned char *calc_ecc)
526 return __nand_correct_data(buf, read_ecc, calc_ecc,
527 ((struct nand_chip *)mtd->priv)->ecc.size);
529 EXPORT_SYMBOL(nand_correct_data);
531 MODULE_LICENSE("GPL");
532 MODULE_AUTHOR("Frans Meulenbroeks <fransmeulenbroeks@gmail.com>");
533 MODULE_DESCRIPTION("Generic NAND ECC support");