// SPDX-License-Identifier: GPL-2.0-or-later
/*
* This file contains an ECC algorithm that detects and corrects 1 bit
* errors in a 256 byte block of data.
*
* Copyright © 2008 Koninklijke Philips Electronics NV.
* Author: Frans Meulenbroeks
*
* Completely replaces the previous ECC implementation which was written by:
* Steven J. Hill ([email protected])
* Thomas Gleixner ([email protected])
*
* Information on how this algorithm works and how it was developed
* can be found in Documentation/driver-api/mtd/nand_ecc.rst
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/nand-ecc-sw-hamming.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
/*
* invparity is a 256 byte table that contains the odd parity
* for each byte. So if the number of bits in a byte is even,
* the array element is 1, and when the number of bits is odd
* the array eleemnt is 0.
*/
static const char invparity[256] = {
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
};
/*
* bitsperbyte contains the number of bits per byte
* this is only used for testing and repairing parity
* (a precalculated value slightly improves performance)
*/
static const char bitsperbyte[256] = {
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
};
/*
* addressbits is a lookup table to filter out the bits from the xor-ed
* ECC data that identify the faulty location.
* this is only used for repairing parity
* see the comments in nand_ecc_sw_hamming_correct for more details
*/
static const char addressbits[256] = {
0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x01,
0x02, 0x02, 0x03, 0x03, 0x02, 0x02, 0x03, 0x03,
0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x01,
0x02, 0x02, 0x03, 0x03, 0x02, 0x02, 0x03, 0x03,
0x04, 0x04, 0x05, 0x05, 0x04, 0x04, 0x05, 0x05,
0x06, 0x06, 0x07, 0x07, 0x06, 0x06, 0x07, 0x07,
0x04, 0x04, 0x05, 0x05, 0x04, 0x04, 0x05, 0x05,
0x06, 0x06, 0x07, 0x07, 0x06, 0x06, 0x07, 0x07,
0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x01,
0x02, 0x02, 0x03, 0x03, 0x02, 0x02, 0x03, 0x03,
0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x01,
0x02, 0x02, 0x03, 0x03, 0x02, 0x02, 0x03, 0x03,
0x04, 0x04, 0x05, 0x05, 0x04, 0x04, 0x05, 0x05,
0x06, 0x06, 0x07, 0x07, 0x06, 0x06, 0x07, 0x07,
0x04, 0x04, 0x05, 0x05, 0x04, 0x04, 0x05, 0x05,
0x06, 0x06, 0x07, 0x07, 0x06, 0x06, 0x07, 0x07,
0x08, 0x08, 0x09, 0x09, 0x08, 0x08, 0x09, 0x09,
0x0a, 0x0a, 0x0b, 0x0b, 0x0a, 0x0a, 0x0b, 0x0b,
0x08, 0x08, 0x09, 0x09, 0x08, 0x08, 0x09, 0x09,
0x0a, 0x0a, 0x0b, 0x0b, 0x0a, 0x0a, 0x0b, 0x0b,
0x0c, 0x0c, 0x0d, 0x0d, 0x0c, 0x0c, 0x0d, 0x0d,
0x0e, 0x0e, 0x0f, 0x0f, 0x0e, 0x0e, 0x0f, 0x0f,
0x0c, 0x0c, 0x0d, 0x0d, 0x0c, 0x0c, 0x0d, 0x0d,
0x0e, 0x0e, 0x0f, 0x0f, 0x0e, 0x0e, 0x0f, 0x0f,
0x08, 0x08, 0x09, 0x09, 0x08, 0x08, 0x09, 0x09,
0x0a, 0x0a, 0x0b, 0x0b, 0x0a, 0x0a, 0x0b, 0x0b,
0x08, 0x08, 0x09, 0x09, 0x08, 0x08, 0x09, 0x09,
0x0a, 0x0a, 0x0b, 0x0b, 0x0a, 0x0a, 0x0b, 0x0b,
0x0c, 0x0c, 0x0d, 0x0d, 0x0c, 0x0c, 0x0d, 0x0d,
0x0e, 0x0e, 0x0f, 0x0f, 0x0e, 0x0e, 0x0f, 0x0f,
0x0c, 0x0c, 0x0d, 0x0d, 0x0c, 0x0c, 0x0d, 0x0d,
0x0e, 0x0e, 0x0f, 0x0f, 0x0e, 0x0e, 0x0f, 0x0f
};
int ecc_sw_hamming_calculate(const unsigned char *buf, unsigned int step_size,
unsigned char *code, bool sm_order)
{
const u32 *bp = (uint32_t *)buf;
const u32 eccsize_mult = (step_size == 256) ? 1 : 2;
/* current value in buffer */
u32 cur;
/* rp0..rp17 are the various accumulated parities (per byte) */
u32 rp0, rp1, rp2, rp3, rp4, rp5, rp6, rp7, rp8, rp9, rp10, rp11, rp12,
rp13, rp14, rp15, rp16, rp17;
/* Cumulative parity for all data */
u32 par;
/* Cumulative parity at the end of the loop (rp12, rp14, rp16) */
u32 tmppar;
int i;
par = 0;
rp4 = 0;
rp6 = 0;
rp8 = 0;
rp10 = 0;
rp12 = 0;
rp14 = 0;
rp16 = 0;
rp17 = 0;
/*
* The loop is unrolled a number of times;
* This avoids if statements to decide on which rp value to update
* Also we process the data by longwords.
* Note: passing unaligned data might give a performance penalty.
* It is assumed that the buffers are aligned.
* tmppar is the cumulative sum of this iteration.
* needed for calculating rp12, rp14, rp16 and par
* also used as a performance improvement for rp6, rp8 and rp10
*/
for (i = 0; i < eccsize_mult << 2; i++) {
cur = *bp++;
tmppar = cur;
rp4 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp6 ^= tmppar;
cur = *bp++;
tmppar ^= cur;
rp4 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp8 ^= tmppar;
cur = *bp++;
tmppar ^= cur;
rp4 ^= cur;
rp6 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp6 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp4 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp10 ^= tmppar;
cur = *bp++;
tmppar ^= cur;
rp4 ^= cur;
rp6 ^= cur;
rp8 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp6 ^= cur;
rp8 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp4 ^= cur;
rp8 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp8 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp4 ^= cur;
rp6 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp6 ^= cur;
cur = *bp++;
tmppar ^= cur;
rp4 ^= cur;
cur = *bp++;
tmppar ^= cur;
par ^= tmppar;
if ((i & 0x1) == 0)
rp12 ^= tmppar;
if ((i & 0x2) == 0)
rp14 ^= tmppar;
if (eccsize_mult == 2 && (i & 0x4) == 0)
rp16 ^= tmppar;
}
/*
* handle the fact that we use longword operations
* we'll bring rp4..rp14..rp16 back to single byte entities by
* shifting and xoring first fold the upper and lower 16 bits,
* then the upper and lower 8 bits.
*/
rp4 ^= (rp4 >> 16);
rp4 ^= (rp4 >> 8);
rp4 &= 0xff;
rp6 ^= (rp6 >> 16);
rp6 ^= (rp6 >> 8);
rp6 &= 0xff;
rp8 ^= (rp8 >> 16);
rp8 ^= (rp8 >> 8);
rp8 &= 0xff;
rp10 ^= (rp10 >> 16);
rp10 ^= (rp10 >> 8);
rp10 &= 0xff;
rp12 ^= (rp12 >> 16);
rp12 ^= (rp12 >> 8);
rp12 &= 0xff;
rp14 ^= (rp14 >> 16);
rp14 ^= (rp14 >> 8);
rp14 &= 0xff;
if (eccsize_mult == 2) {
rp16 ^= (rp16 >> 16);
rp16 ^= (rp16 >> 8);
rp16 &= 0xff;
}
/*
* we also need to calculate the row parity for rp0..rp3
* This is present in par, because par is now
* rp3 rp3 rp2 rp2 in little endian and
* rp2 rp2 rp3 rp3 in big endian
* as well as
* rp1 rp0 rp1 rp0 in little endian and
* rp0 rp1 rp0 rp1 in big endian
* First calculate rp2 and rp3
*/
#ifdef __BIG_ENDIAN
rp2 = (par >> 16);
rp2 ^= (rp2 >> 8);
rp2 &= 0xff;
rp3 = par & 0xffff;
rp3 ^= (rp3 >> 8);
rp3 &= 0xff;
#else
rp3 = (par >> 16);
rp3 ^= (rp3 >> 8);
rp3 &= 0xff;
rp2 = par & 0xffff;
rp2 ^= (rp2 >> 8);
rp2 &= 0xff;
#endif
/* reduce par to 16 bits then calculate rp1 and rp0 */
par ^= (par >> 16);
#ifdef __BIG_ENDIAN
rp0 = (par >> 8) & 0xff;
rp1 = (par & 0xff);
#else
rp1 = (par >> 8) & 0xff;
rp0 = (par & 0xff);
#endif
/* finally reduce par to 8 bits */
par ^= (par >> 8);
par &= 0xff;
/*
* and calculate rp5..rp15..rp17
* note that par = rp4 ^ rp5 and due to the commutative property
* of the ^ operator we can say:
* rp5 = (par ^ rp4);
* The & 0xff seems superfluous, but benchmarking learned that
* leaving it out gives slightly worse results. No idea why, probably
* it has to do with the way the pipeline in pentium is organized.
*/
rp5 = (par ^ rp4) & 0xff;
rp7 = (par ^ rp6) & 0xff;
rp9 = (par ^ rp8) & 0xff;
rp11 = (par ^ rp10) & 0xff;
rp13 = (par ^ rp12) & 0xff;
rp15 = (par ^ rp14) & 0xff;
if (eccsize_mult == 2)
rp17 = (par ^ rp16) & 0xff;
/*
* Finally calculate the ECC bits.
* Again here it might seem that there are performance optimisations
* possible, but benchmarks showed that on the system this is developed
* the code below is the fastest
*/
if (sm_order) {
code[0] = (invparity[rp7] << 7) | (invparity[rp6] << 6) |
(invparity[rp5] << 5) | (invparity[rp4] << 4) |
(invparity[rp3] << 3) | (invparity[rp2] << 2) |
(invparity[rp1] << 1) | (invparity[rp0]);
code[1] = (invparity[rp15] << 7) | (invparity[rp14] << 6) |
(invparity[rp13] << 5) | (invparity[rp12] << 4) |
(invparity[rp11] << 3) | (invparity[rp10] << 2) |
(invparity[rp9] << 1) | (invparity[rp8]);
} else {
code[1] = (invparity[rp7] << 7) | (invparity[rp6] << 6) |
(invparity[rp5] << 5) | (invparity[rp4] << 4) |
(invparity[rp3] << 3) | (invparity[rp2] << 2) |
(invparity[rp1] << 1) | (invparity[rp0]);
code[0] = (invparity[rp15] << 7) | (invparity[rp14] << 6) |
(invparity[rp13] << 5) | (invparity[rp12] << 4) |
(invparity[rp11] << 3) | (invparity[rp10] << 2) |
(invparity[rp9] << 1) | (invparity[rp8]);
}
if (eccsize_mult == 1)
code[2] =
(invparity[par & 0xf0] << 7) |
(invparity[par & 0x0f] << 6) |
(invparity[par & 0xcc] << 5) |
(invparity[par & 0x33] << 4) |
(invparity[par & 0xaa] << 3) |
(invparity[par & 0x55] << 2) |
3;
else
code[2] =
(invparity[par & 0xf0] << 7) |
(invparity[par & 0x0f] << 6) |
(invparity[par & 0xcc] << 5) |
(invparity[par & 0x33] << 4) |
(invparity[par & 0xaa] << 3) |
(invparity[par & 0x55] << 2) |
(invparity[rp17] << 1) |
(invparity[rp16] << 0);
return 0;
}
EXPORT_SYMBOL(ecc_sw_hamming_calculate);
/**
* nand_ecc_sw_hamming_calculate - Calculate 3-byte ECC for 256/512-byte block
* @nand: NAND device
* @buf: Input buffer with raw data
* @code: Output buffer with ECC
*/
int nand_ecc_sw_hamming_calculate(struct nand_device *nand,
const unsigned char *buf, unsigned char *code)
{
struct nand_ecc_sw_hamming_conf *engine_conf = nand->ecc.ctx.priv;
unsigned int step_size = nand->ecc.ctx.conf.step_size;
bool sm_order = engine_conf ? engine_conf->sm_order : false;
return ecc_sw_hamming_calculate(buf, step_size, code, sm_order);
}
EXPORT_SYMBOL(nand_ecc_sw_hamming_calculate);
int ecc_sw_hamming_correct(unsigned char *buf, unsigned char *read_ecc,
unsigned char *calc_ecc, unsigned int step_size,
bool sm_order)
{
const u32 eccsize_mult = step_size >> 8;
unsigned char b0, b1, b2, bit_addr;
unsigned int byte_addr;
/*
* b0 to b2 indicate which bit is faulty (if any)
* we might need the xor result more than once,
* so keep them in a local var
*/
if (sm_order) {
b0 = read_ecc[0] ^ calc_ecc[0];
b1 = read_ecc[1] ^ calc_ecc[1];
} else {
b0 = read_ecc[1] ^ calc_ecc[1];
b1 = read_ecc[0] ^ calc_ecc[0];
}
b2 = read_ecc[2] ^ calc_ecc[2];
/* check if there are any bitfaults */
/* repeated if statements are slightly more efficient than switch ... */
/* ordered in order of likelihood */
if ((b0 | b1 | b2) == 0)
return 0; /* no error */
if ((((b0 ^ (b0 >> 1)) & 0x55) == 0x55) &&
(((b1 ^ (b1 >> 1)) & 0x55) == 0x55) &&
((eccsize_mult == 1 && ((b2 ^ (b2 >> 1)) & 0x54) == 0x54) ||
(eccsize_mult == 2 && ((b2 ^ (b2 >> 1)) & 0x55) == 0x55))) {
/* single bit error */
/*
* rp17/rp15/13/11/9/7/5/3/1 indicate which byte is the faulty
* byte, cp 5/3/1 indicate the faulty bit.
* A lookup table (called addressbits) is used to filter
* the bits from the byte they are in.
* A marginal optimisation is possible by having three
* different lookup tables.
* One as we have now (for b0), one for b2
* (that would avoid the >> 1), and one for b1 (with all values
* << 4). However it was felt that introducing two more tables
* hardly justify the gain.
*
* The b2 shift is there to get rid of the lowest two bits.
* We could also do addressbits[b2] >> 1 but for the
* performance it does not make any difference
*/
if (eccsize_mult == 1)
byte_addr = (addressbits[b1] << 4) + addressbits[b0];
else
byte_addr = (addressbits[b2 & 0x3] << 8) +
(addressbits[b1] << 4) + addressbits[b0];
bit_addr = addressbits[b2 >> 2];
/* flip the bit */
buf[byte_addr] ^= (1 << bit_addr);
return 1;
}
/* count nr of bits; use table lookup, faster than calculating it */
if ((bitsperbyte[b0] + bitsperbyte[b1] + bitsperbyte[b2]) == 1)
return 1; /* error in ECC data; no action needed */
pr_err("%s: uncorrectable ECC error\n", __func__);
return -EBADMSG;
}
EXPORT_SYMBOL(ecc_sw_hamming_correct);
/**
* nand_ecc_sw_hamming_correct - Detect and correct bit error(s)
* @nand: NAND device
* @buf: Raw data read from the chip
* @read_ecc: ECC bytes read from the chip
* @calc_ecc: ECC calculated from the raw data
*
* Detect and correct up to 1 bit error per 256/512-byte block.
*/
int nand_ecc_sw_hamming_correct(struct nand_device *nand, unsigned char *buf,
unsigned char *read_ecc,
unsigned char *calc_ecc)
{
struct nand_ecc_sw_hamming_conf *engine_conf = nand->ecc.ctx.priv;
unsigned int step_size = nand->ecc.ctx.conf.step_size;
bool sm_order = engine_conf ? engine_conf->sm_order : false;
return ecc_sw_hamming_correct(buf, read_ecc, calc_ecc, step_size,
sm_order);
}
EXPORT_SYMBOL(nand_ecc_sw_hamming_correct);
int nand_ecc_sw_hamming_init_ctx(struct nand_device *nand)
{
struct nand_ecc_props *conf = &nand->ecc.ctx.conf;
struct nand_ecc_sw_hamming_conf *engine_conf;
struct mtd_info *mtd = nanddev_to_mtd(nand);
int ret;
if (!mtd->ooblayout) {
switch (mtd->oobsize) {
case 8:
case 16:
mtd_set_ooblayout(mtd, nand_get_small_page_ooblayout());
break;
case 64:
case 128:
mtd_set_ooblayout(mtd,
nand_get_large_page_hamming_ooblayout());
break;
default:
return -ENOTSUPP;
}
}
conf->engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
conf->algo = NAND_ECC_ALGO_HAMMING;
conf->step_size = nand->ecc.user_conf.step_size;
conf->strength = 1;
/* Use the strongest configuration by default */
if (conf->step_size != 256 && conf->step_size != 512)
conf->step_size = 256;
engine_conf = kzalloc(sizeof(*engine_conf), GFP_KERNEL);
if (!engine_conf)
return -ENOMEM;
ret = nand_ecc_init_req_tweaking(&engine_conf->req_ctx, nand);
if (ret)
goto free_engine_conf;
engine_conf->code_size = 3;
engine_conf->calc_buf = kzalloc(mtd->oobsize, GFP_KERNEL);
engine_conf->code_buf = kzalloc(mtd->oobsize, GFP_KERNEL);
if (!engine_conf->calc_buf || !engine_conf->code_buf) {
ret = -ENOMEM;
goto free_bufs;
}
nand->ecc.ctx.priv = engine_conf;
nand->ecc.ctx.nsteps = mtd->writesize / conf->step_size;
nand->ecc.ctx.total = nand->ecc.ctx.nsteps * engine_conf->code_size;
return 0;
free_bufs:
nand_ecc_cleanup_req_tweaking(&engine_conf->req_ctx);
kfree(engine_conf->calc_buf);
kfree(engine_conf->code_buf);
free_engine_conf:
kfree(engine_conf);
return ret;
}
EXPORT_SYMBOL(nand_ecc_sw_hamming_init_ctx);
void nand_ecc_sw_hamming_cleanup_ctx(struct nand_device *nand)
{
struct nand_ecc_sw_hamming_conf *engine_conf = nand->ecc.ctx.priv;
if (engine_conf) {
nand_ecc_cleanup_req_tweaking(&engine_conf->req_ctx);
kfree(engine_conf->calc_buf);
kfree(engine_conf->code_buf);
kfree(engine_conf);
}
}
EXPORT_SYMBOL(nand_ecc_sw_hamming_cleanup_ctx);
static int nand_ecc_sw_hamming_prepare_io_req(struct nand_device *nand,
struct nand_page_io_req *req)
{
struct nand_ecc_sw_hamming_conf *engine_conf = nand->ecc.ctx.priv;
struct mtd_info *mtd = nanddev_to_mtd(nand);
int eccsize = nand->ecc.ctx.conf.step_size;
int eccbytes = engine_conf->code_size;
int eccsteps = nand->ecc.ctx.nsteps;
int total = nand->ecc.ctx.total;
u8 *ecccalc = engine_conf->calc_buf;
const u8 *data;
int i;
/* Nothing to do for a raw operation */
if (req->mode == MTD_OPS_RAW)
return 0;
/* This engine does not provide BBM/free OOB bytes protection */
if (!req->datalen)
return 0;
nand_ecc_tweak_req(&engine_conf->req_ctx, req);
/* No more preparation for page read */
if (req->type == NAND_PAGE_READ)
return 0;
/* Preparation for page write: derive the ECC bytes and place them */
for (i = 0, data = req->databuf.out;
eccsteps;
eccsteps--, i += eccbytes, data += eccsize)
nand_ecc_sw_hamming_calculate(nand, data, &ecccalc[i]);
return mtd_ooblayout_set_eccbytes(mtd, ecccalc, (void *)req->oobbuf.out,
0, total);
}
static int nand_ecc_sw_hamming_finish_io_req(struct nand_device *nand,
struct nand_page_io_req *req)
{
struct nand_ecc_sw_hamming_conf *engine_conf = nand->ecc.ctx.priv;
struct mtd_info *mtd = nanddev_to_mtd(nand);
int eccsize = nand->ecc.ctx.conf.step_size;
int total = nand->ecc.ctx.total;
int eccbytes = engine_conf->code_size;
int eccsteps = nand->ecc.ctx.nsteps;
u8 *ecccalc = engine_conf->calc_buf;
u8 *ecccode = engine_conf->code_buf;
unsigned int max_bitflips = 0;
u8 *data = req->databuf.in;
int i, ret;
/* Nothing to do for a raw operation */
if (req->mode == MTD_OPS_RAW)
return 0;
/* This engine does not provide BBM/free OOB bytes protection */
if (!req->datalen)
return 0;
/* No more preparation for page write */
if (req->type == NAND_PAGE_WRITE) {
nand_ecc_restore_req(&engine_conf->req_ctx, req);
return 0;
}
/* Finish a page read: retrieve the (raw) ECC bytes*/
ret = mtd_ooblayout_get_eccbytes(mtd, ecccode, req->oobbuf.in, 0,
total);
if (ret)
return ret;
/* Calculate the ECC bytes */
for (i = 0; eccsteps; eccsteps--, i += eccbytes, data += eccsize)
nand_ecc_sw_hamming_calculate(nand, data, &ecccalc[i]);
/* Finish a page read: compare and correct */
for (eccsteps = nand->ecc.ctx.nsteps, i = 0, data = req->databuf.in;
eccsteps;
eccsteps--, i += eccbytes, data += eccsize) {
int stat = nand_ecc_sw_hamming_correct(nand, data,
&ecccode[i],
&ecccalc[i]);
if (stat < 0) {
mtd->ecc_stats.failed++;
} else {
mtd->ecc_stats.corrected += stat;
max_bitflips = max_t(unsigned int, max_bitflips, stat);
}
}
nand_ecc_restore_req(&engine_conf->req_ctx, req);
return max_bitflips;
}
static struct nand_ecc_engine_ops nand_ecc_sw_hamming_engine_ops = {
.init_ctx = nand_ecc_sw_hamming_init_ctx,
.cleanup_ctx = nand_ecc_sw_hamming_cleanup_ctx,
.prepare_io_req = nand_ecc_sw_hamming_prepare_io_req,
.finish_io_req = nand_ecc_sw_hamming_finish_io_req,
};
static struct nand_ecc_engine nand_ecc_sw_hamming_engine = {
.ops = &nand_ecc_sw_hamming_engine_ops,
};
struct nand_ecc_engine *nand_ecc_sw_hamming_get_engine(void)
{
return &nand_ecc_sw_hamming_engine;
}
EXPORT_SYMBOL(nand_ecc_sw_hamming_get_engine);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Frans Meulenbroeks <[email protected]>");
MODULE_DESCRIPTION("NAND software Hamming ECC support");
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