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-rw-r--r--drivers/mtd/nand/nand_ecc.c86
1 files changed, 62 insertions, 24 deletions
diff --git a/drivers/mtd/nand/nand_ecc.c b/drivers/mtd/nand/nand_ecc.c
index fd19787c9ce7..868147acce2c 100644
--- a/drivers/mtd/nand/nand_ecc.c
+++ b/drivers/mtd/nand/nand_ecc.c
@@ -42,6 +42,8 @@
42#include <linux/types.h> 42#include <linux/types.h>
43#include <linux/kernel.h> 43#include <linux/kernel.h>
44#include <linux/module.h> 44#include <linux/module.h>
45#include <linux/mtd/mtd.h>
46#include <linux/mtd/nand.h>
45#include <linux/mtd/nand_ecc.h> 47#include <linux/mtd/nand_ecc.h>
46#include <asm/byteorder.h> 48#include <asm/byteorder.h>
47#else 49#else
@@ -148,8 +150,9 @@ static const char addressbits[256] = {
148}; 150};
149 151
150/** 152/**
151 * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256-byte block 153 * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
152 * @mtd: MTD block structure (unused) 154 * block
155 * @mtd: MTD block structure
153 * @buf: input buffer with raw data 156 * @buf: input buffer with raw data
154 * @code: output buffer with ECC 157 * @code: output buffer with ECC
155 */ 158 */
@@ -158,13 +161,18 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
158{ 161{
159 int i; 162 int i;
160 const uint32_t *bp = (uint32_t *)buf; 163 const uint32_t *bp = (uint32_t *)buf;
164 /* 256 or 512 bytes/ecc */
165 const uint32_t eccsize_mult =
166 (((struct nand_chip *)mtd->priv)->ecc.size) >> 8;
161 uint32_t cur; /* current value in buffer */ 167 uint32_t cur; /* current value in buffer */
162 /* rp0..rp15 are the various accumulated parities (per byte) */ 168 /* rp0..rp15..rp17 are the various accumulated parities (per byte) */
163 uint32_t rp0, rp1, rp2, rp3, rp4, rp5, rp6, rp7; 169 uint32_t rp0, rp1, rp2, rp3, rp4, rp5, rp6, rp7;
164 uint32_t rp8, rp9, rp10, rp11, rp12, rp13, rp14, rp15; 170 uint32_t rp8, rp9, rp10, rp11, rp12, rp13, rp14, rp15, rp16;
171 uint32_t uninitialized_var(rp17); /* to make compiler happy */
165 uint32_t par; /* the cumulative parity for all data */ 172 uint32_t par; /* the cumulative parity for all data */
166 uint32_t tmppar; /* the cumulative parity for this iteration; 173 uint32_t tmppar; /* the cumulative parity for this iteration;
167 for rp12 and rp14 at the end of the loop */ 174 for rp12, rp14 and rp16 at the end of the
175 loop */
168 176
169 par = 0; 177 par = 0;
170 rp4 = 0; 178 rp4 = 0;
@@ -173,6 +181,7 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
173 rp10 = 0; 181 rp10 = 0;
174 rp12 = 0; 182 rp12 = 0;
175 rp14 = 0; 183 rp14 = 0;
184 rp16 = 0;
176 185
177 /* 186 /*
178 * The loop is unrolled a number of times; 187 * The loop is unrolled a number of times;
@@ -181,10 +190,10 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
181 * Note: passing unaligned data might give a performance penalty. 190 * Note: passing unaligned data might give a performance penalty.
182 * It is assumed that the buffers are aligned. 191 * It is assumed that the buffers are aligned.
183 * tmppar is the cumulative sum of this iteration. 192 * tmppar is the cumulative sum of this iteration.
184 * needed for calculating rp12, rp14 and par 193 * needed for calculating rp12, rp14, rp16 and par
185 * also used as a performance improvement for rp6, rp8 and rp10 194 * also used as a performance improvement for rp6, rp8 and rp10
186 */ 195 */
187 for (i = 0; i < 4; i++) { 196 for (i = 0; i < eccsize_mult << 2; i++) {
188 cur = *bp++; 197 cur = *bp++;
189 tmppar = cur; 198 tmppar = cur;
190 rp4 ^= cur; 199 rp4 ^= cur;
@@ -247,12 +256,14 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
247 rp12 ^= tmppar; 256 rp12 ^= tmppar;
248 if ((i & 0x2) == 0) 257 if ((i & 0x2) == 0)
249 rp14 ^= tmppar; 258 rp14 ^= tmppar;
259 if (eccsize_mult == 2 && (i & 0x4) == 0)
260 rp16 ^= tmppar;
250 } 261 }
251 262
252 /* 263 /*
253 * handle the fact that we use longword operations 264 * handle the fact that we use longword operations
254 * we'll bring rp4..rp14 back to single byte entities by shifting and 265 * we'll bring rp4..rp14..rp16 back to single byte entities by
255 * xoring first fold the upper and lower 16 bits, 266 * shifting and xoring first fold the upper and lower 16 bits,
256 * then the upper and lower 8 bits. 267 * then the upper and lower 8 bits.
257 */ 268 */
258 rp4 ^= (rp4 >> 16); 269 rp4 ^= (rp4 >> 16);
@@ -273,6 +284,11 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
273 rp14 ^= (rp14 >> 16); 284 rp14 ^= (rp14 >> 16);
274 rp14 ^= (rp14 >> 8); 285 rp14 ^= (rp14 >> 8);
275 rp14 &= 0xff; 286 rp14 &= 0xff;
287 if (eccsize_mult == 2) {
288 rp16 ^= (rp16 >> 16);
289 rp16 ^= (rp16 >> 8);
290 rp16 &= 0xff;
291 }
276 292
277 /* 293 /*
278 * we also need to calculate the row parity for rp0..rp3 294 * we also need to calculate the row parity for rp0..rp3
@@ -315,7 +331,7 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
315 par &= 0xff; 331 par &= 0xff;
316 332
317 /* 333 /*
318 * and calculate rp5..rp15 334 * and calculate rp5..rp15..rp17
319 * note that par = rp4 ^ rp5 and due to the commutative property 335 * note that par = rp4 ^ rp5 and due to the commutative property
320 * of the ^ operator we can say: 336 * of the ^ operator we can say:
321 * rp5 = (par ^ rp4); 337 * rp5 = (par ^ rp4);
@@ -329,6 +345,8 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
329 rp11 = (par ^ rp10) & 0xff; 345 rp11 = (par ^ rp10) & 0xff;
330 rp13 = (par ^ rp12) & 0xff; 346 rp13 = (par ^ rp12) & 0xff;
331 rp15 = (par ^ rp14) & 0xff; 347 rp15 = (par ^ rp14) & 0xff;
348 if (eccsize_mult == 2)
349 rp17 = (par ^ rp16) & 0xff;
332 350
333 /* 351 /*
334 * Finally calculate the ecc bits. 352 * Finally calculate the ecc bits.
@@ -375,32 +393,46 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
375 (invparity[rp9] << 1) | 393 (invparity[rp9] << 1) |
376 (invparity[rp8]); 394 (invparity[rp8]);
377#endif 395#endif
378 code[2] = 396 if (eccsize_mult == 1)
379 (invparity[par & 0xf0] << 7) | 397 code[2] =
380 (invparity[par & 0x0f] << 6) | 398 (invparity[par & 0xf0] << 7) |
381 (invparity[par & 0xcc] << 5) | 399 (invparity[par & 0x0f] << 6) |
382 (invparity[par & 0x33] << 4) | 400 (invparity[par & 0xcc] << 5) |
383 (invparity[par & 0xaa] << 3) | 401 (invparity[par & 0x33] << 4) |
384 (invparity[par & 0x55] << 2) | 402 (invparity[par & 0xaa] << 3) |
385 3; 403 (invparity[par & 0x55] << 2) |
404 3;
405 else
406 code[2] =
407 (invparity[par & 0xf0] << 7) |
408 (invparity[par & 0x0f] << 6) |
409 (invparity[par & 0xcc] << 5) |
410 (invparity[par & 0x33] << 4) |
411 (invparity[par & 0xaa] << 3) |
412 (invparity[par & 0x55] << 2) |
413 (invparity[rp17] << 1) |
414 (invparity[rp16] << 0);
386 return 0; 415 return 0;
387} 416}
388EXPORT_SYMBOL(nand_calculate_ecc); 417EXPORT_SYMBOL(nand_calculate_ecc);
389 418
390/** 419/**
391 * nand_correct_data - [NAND Interface] Detect and correct bit error(s) 420 * nand_correct_data - [NAND Interface] Detect and correct bit error(s)
392 * @mtd: MTD block structure (unused) 421 * @mtd: MTD block structure
393 * @buf: raw data read from the chip 422 * @buf: raw data read from the chip
394 * @read_ecc: ECC from the chip 423 * @read_ecc: ECC from the chip
395 * @calc_ecc: the ECC calculated from raw data 424 * @calc_ecc: the ECC calculated from raw data
396 * 425 *
397 * Detect and correct a 1 bit error for 256 byte block 426 * Detect and correct a 1 bit error for 256/512 byte block
398 */ 427 */
399int nand_correct_data(struct mtd_info *mtd, unsigned char *buf, 428int nand_correct_data(struct mtd_info *mtd, unsigned char *buf,
400 unsigned char *read_ecc, unsigned char *calc_ecc) 429 unsigned char *read_ecc, unsigned char *calc_ecc)
401{ 430{
402 unsigned char b0, b1, b2; 431 unsigned char b0, b1, b2;
403 unsigned char byte_addr, bit_addr; 432 unsigned char byte_addr, bit_addr;
433 /* 256 or 512 bytes/ecc */
434 const uint32_t eccsize_mult =
435 (((struct nand_chip *)mtd->priv)->ecc.size) >> 8;
404 436
405 /* 437 /*
406 * b0 to b2 indicate which bit is faulty (if any) 438 * b0 to b2 indicate which bit is faulty (if any)
@@ -426,10 +458,12 @@ int nand_correct_data(struct mtd_info *mtd, unsigned char *buf,
426 458
427 if ((((b0 ^ (b0 >> 1)) & 0x55) == 0x55) && 459 if ((((b0 ^ (b0 >> 1)) & 0x55) == 0x55) &&
428 (((b1 ^ (b1 >> 1)) & 0x55) == 0x55) && 460 (((b1 ^ (b1 >> 1)) & 0x55) == 0x55) &&
429 (((b2 ^ (b2 >> 1)) & 0x54) == 0x54)) { /* single bit error */ 461 ((eccsize_mult == 1 && ((b2 ^ (b2 >> 1)) & 0x54) == 0x54) ||
462 (eccsize_mult == 2 && ((b2 ^ (b2 >> 1)) & 0x55) == 0x55))) {
463 /* single bit error */
430 /* 464 /*
431 * rp15/13/11/9/7/5/3/1 indicate which byte is the faulty byte 465 * rp17/rp15/13/11/9/7/5/3/1 indicate which byte is the faulty
432 * cp 5/3/1 indicate the faulty bit. 466 * byte, cp 5/3/1 indicate the faulty bit.
433 * A lookup table (called addressbits) is used to filter 467 * A lookup table (called addressbits) is used to filter
434 * the bits from the byte they are in. 468 * the bits from the byte they are in.
435 * A marginal optimisation is possible by having three 469 * A marginal optimisation is possible by having three
@@ -443,7 +477,11 @@ int nand_correct_data(struct mtd_info *mtd, unsigned char *buf,
443 * We could also do addressbits[b2] >> 1 but for the 477 * We could also do addressbits[b2] >> 1 but for the
444 * performace it does not make any difference 478 * performace it does not make any difference
445 */ 479 */
446 byte_addr = (addressbits[b1] << 4) + addressbits[b0]; 480 if (eccsize_mult == 1)
481 byte_addr = (addressbits[b1] << 4) + addressbits[b0];
482 else
483 byte_addr = (addressbits[b2 & 0x3] << 8) +
484 (addressbits[b1] << 4) + addressbits[b0];
447 bit_addr = addressbits[b2 >> 2]; 485 bit_addr = addressbits[b2 >> 2];
448 /* flip the bit */ 486 /* flip the bit */
449 buf[byte_addr] ^= (1 << bit_addr); 487 buf[byte_addr] ^= (1 << bit_addr);