From c8ae3f744ddca0da164bcacee42d1d4b6fe7027d Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Tue, 19 May 2020 09:45:42 +0200 Subject: lib/bch: Rework a little bit the exported function names There are four exported functions, all suffixed by _bch, which is clearly not the norm. Let's rename them by prefixing them with bch_ instead. This is a mechanical change: init_bch -> bch_init free_bch -> bch_free encode_bch -> bch_encode decode_bch -> bch_decode Signed-off-by: Miquel Raynal Reviewed-by: Boris Brezillon Link: https://lore.kernel.org/linux-mtd/20200519074549.23673-2-miquel.raynal@bootlin.com --- lib/bch.c | 64 +++++++++++++++++++++++++++++++-------------------------------- 1 file changed, 32 insertions(+), 32 deletions(-) (limited to 'lib') diff --git a/lib/bch.c b/lib/bch.c index 052d3fb753a0..1091841ac716 100644 --- a/lib/bch.c +++ b/lib/bch.c @@ -23,15 +23,15 @@ * This library provides runtime configurable encoding/decoding of binary * Bose-Chaudhuri-Hocquenghem (BCH) codes. * - * Call init_bch to get a pointer to a newly allocated bch_control structure for + * Call bch_init to get a pointer to a newly allocated bch_control structure for * the given m (Galois field order), t (error correction capability) and * (optional) primitive polynomial parameters. * - * Call encode_bch to compute and store ecc parity bytes to a given buffer. - * Call decode_bch to detect and locate errors in received data. + * Call bch_encode to compute and store ecc parity bytes to a given buffer. + * Call bch_decode to detect and locate errors in received data. * * On systems supporting hw BCH features, intermediate results may be provided - * to decode_bch in order to skip certain steps. See decode_bch() documentation + * to bch_decode in order to skip certain steps. See bch_decode() documentation * for details. * * Option CONFIG_BCH_CONST_PARAMS can be used to force fixed values of @@ -115,9 +115,9 @@ struct gf_poly_deg1 { }; /* - * same as encode_bch(), but process input data one byte at a time + * same as bch_encode(), but process input data one byte at a time */ -static void encode_bch_unaligned(struct bch_control *bch, +static void bch_encode_unaligned(struct bch_control *bch, const unsigned char *data, unsigned int len, uint32_t *ecc) { @@ -174,7 +174,7 @@ static void store_ecc8(struct bch_control *bch, uint8_t *dst, } /** - * encode_bch - calculate BCH ecc parity of data + * bch_encode - calculate BCH ecc parity of data * @bch: BCH control structure * @data: data to encode * @len: data length in bytes @@ -187,7 +187,7 @@ static void store_ecc8(struct bch_control *bch, uint8_t *dst, * The exact number of computed ecc parity bits is given by member @ecc_bits of * @bch; it may be less than m*t for large values of t. */ -void encode_bch(struct bch_control *bch, const uint8_t *data, +void bch_encode(struct bch_control *bch, const uint8_t *data, unsigned int len, uint8_t *ecc) { const unsigned int l = BCH_ECC_WORDS(bch)-1; @@ -215,7 +215,7 @@ void encode_bch(struct bch_control *bch, const uint8_t *data, m = ((unsigned long)data) & 3; if (m) { mlen = (len < (4-m)) ? len : 4-m; - encode_bch_unaligned(bch, data, mlen, bch->ecc_buf); + bch_encode_unaligned(bch, data, mlen, bch->ecc_buf); data += mlen; len -= mlen; } @@ -255,13 +255,13 @@ void encode_bch(struct bch_control *bch, const uint8_t *data, /* process last unaligned bytes */ if (len) - encode_bch_unaligned(bch, data, len, bch->ecc_buf); + bch_encode_unaligned(bch, data, len, bch->ecc_buf); /* store ecc parity bytes into original parity buffer */ if (ecc) store_ecc8(bch, ecc, bch->ecc_buf); } -EXPORT_SYMBOL_GPL(encode_bch); +EXPORT_SYMBOL_GPL(bch_encode); static inline int modulo(struct bch_control *bch, unsigned int v) { @@ -952,7 +952,7 @@ static int chien_search(struct bch_control *bch, unsigned int len, #endif /* USE_CHIEN_SEARCH */ /** - * decode_bch - decode received codeword and find bit error locations + * bch_decode - decode received codeword and find bit error locations * @bch: BCH control structure * @data: received data, ignored if @calc_ecc is provided * @len: data length in bytes, must always be provided @@ -966,22 +966,22 @@ static int chien_search(struct bch_control *bch, unsigned int len, * invalid parameters were provided * * Depending on the available hw BCH support and the need to compute @calc_ecc - * separately (using encode_bch()), this function should be called with one of + * separately (using bch_encode()), this function should be called with one of * the following parameter configurations - * * by providing @data and @recv_ecc only: - * decode_bch(@bch, @data, @len, @recv_ecc, NULL, NULL, @errloc) + * bch_decode(@bch, @data, @len, @recv_ecc, NULL, NULL, @errloc) * * by providing @recv_ecc and @calc_ecc: - * decode_bch(@bch, NULL, @len, @recv_ecc, @calc_ecc, NULL, @errloc) + * bch_decode(@bch, NULL, @len, @recv_ecc, @calc_ecc, NULL, @errloc) * * by providing ecc = recv_ecc XOR calc_ecc: - * decode_bch(@bch, NULL, @len, NULL, ecc, NULL, @errloc) + * bch_decode(@bch, NULL, @len, NULL, ecc, NULL, @errloc) * * by providing syndrome results @syn: - * decode_bch(@bch, NULL, @len, NULL, NULL, @syn, @errloc) + * bch_decode(@bch, NULL, @len, NULL, NULL, @syn, @errloc) * - * Once decode_bch() has successfully returned with a positive value, error + * Once bch_decode() has successfully returned with a positive value, error * locations returned in array @errloc should be interpreted as follows - * * if (errloc[n] >= 8*len), then n-th error is located in ecc (no need for @@ -993,7 +993,7 @@ static int chien_search(struct bch_control *bch, unsigned int len, * Note that this function does not perform any data correction by itself, it * merely indicates error locations. */ -int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len, +int bch_decode(struct bch_control *bch, const uint8_t *data, unsigned int len, const uint8_t *recv_ecc, const uint8_t *calc_ecc, const unsigned int *syn, unsigned int *errloc) { @@ -1012,7 +1012,7 @@ int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len, /* compute received data ecc into an internal buffer */ if (!data || !recv_ecc) return -EINVAL; - encode_bch(bch, data, len, NULL); + bch_encode(bch, data, len, NULL); } else { /* load provided calculated ecc */ load_ecc8(bch, bch->ecc_buf, calc_ecc); @@ -1053,7 +1053,7 @@ int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len, } return (err >= 0) ? err : -EBADMSG; } -EXPORT_SYMBOL_GPL(decode_bch); +EXPORT_SYMBOL_GPL(bch_decode); /* * generate Galois field lookup tables @@ -1236,7 +1236,7 @@ finish: } /** - * init_bch - initialize a BCH encoder/decoder + * bch_init - initialize a BCH encoder/decoder * @m: Galois field order, should be in the range 5-15 * @t: maximum error correction capability, in bits * @prim_poly: user-provided primitive polynomial (or 0 to use default) @@ -1246,17 +1246,17 @@ finish: * * This initialization can take some time, as lookup tables are built for fast * encoding/decoding; make sure not to call this function from a time critical - * path. Usually, init_bch() should be called on module/driver init and - * free_bch() should be called to release memory on exit. + * path. Usually, bch_init() should be called on module/driver init and + * bch_free() should be called to release memory on exit. * * You may provide your own primitive polynomial of degree @m in argument - * @prim_poly, or let init_bch() use its default polynomial. + * @prim_poly, or let bch_init() use its default polynomial. * - * Once init_bch() has successfully returned a pointer to a newly allocated + * Once bch_init() has successfully returned a pointer to a newly allocated * BCH control structure, ecc length in bytes is given by member @ecc_bytes of * the structure. */ -struct bch_control *init_bch(int m, int t, unsigned int prim_poly) +struct bch_control *bch_init(int m, int t, unsigned int prim_poly) { int err = 0; unsigned int i, words; @@ -1347,16 +1347,16 @@ struct bch_control *init_bch(int m, int t, unsigned int prim_poly) return bch; fail: - free_bch(bch); + bch_free(bch); return NULL; } -EXPORT_SYMBOL_GPL(init_bch); +EXPORT_SYMBOL_GPL(bch_init); /** - * free_bch - free the BCH control structure + * bch_free - free the BCH control structure * @bch: BCH control structure to release */ -void free_bch(struct bch_control *bch) +void bch_free(struct bch_control *bch) { unsigned int i; @@ -1377,7 +1377,7 @@ void free_bch(struct bch_control *bch) kfree(bch); } } -EXPORT_SYMBOL_GPL(free_bch); +EXPORT_SYMBOL_GPL(bch_free); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Ivan Djelic "); -- cgit v1.2.3-70-g09d2 From 1759279ad138cb0a903224a89f4bf40f69c417e8 Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Tue, 19 May 2020 09:45:43 +0200 Subject: lib/bch: Allow easy bit swapping It seems that several hardware ECC engine use a swapped representation of bytes compared to software. This might having to do with how the ECC engine is wired to the NAND controller or the order the bits are passed to the hardware BCH logic. This means that when the software BCH engine is working in conjunction with data generated with hardware, sometimes we might need to swap the bits inside bytes, eg: 0x0A = b0000_1010 -> b0101_0000 = 0x50 Make it possible by adding a boolean to the BCH initialization routine. Regarding the implementation itself, this is a rather simple approach that can probably be enhanced in the future by preparing the ->a_{mod,pow}_tab tables with the swapping in mind. Suggested-by: Boris Brezillon Signed-off-by: Miquel Raynal Reviewed-by: Boris Brezillon Link: https://lore.kernel.org/linux-mtd/20200519074549.23673-3-miquel.raynal@bootlin.com --- drivers/mtd/devices/docg3.c | 2 +- drivers/mtd/nand/raw/nand_bch.c | 2 +- include/linux/bch.h | 5 ++- lib/bch.c | 90 ++++++++++++++++++++++++++++++++++------- 4 files changed, 82 insertions(+), 17 deletions(-) (limited to 'lib') diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c index 799df8d03357..a030792115bc 100644 --- a/drivers/mtd/devices/docg3.c +++ b/drivers/mtd/devices/docg3.c @@ -1985,7 +1985,7 @@ static int __init docg3_probe(struct platform_device *pdev) cascade->base = base; mutex_init(&cascade->lock); cascade->bch = bch_init(DOC_ECC_BCH_M, DOC_ECC_BCH_T, - DOC_ECC_BCH_PRIMPOLY); + DOC_ECC_BCH_PRIMPOLY, false); if (!cascade->bch) return ret; diff --git a/drivers/mtd/nand/raw/nand_bch.c b/drivers/mtd/nand/raw/nand_bch.c index d95fcc7358e9..d5af8c5fd02f 100644 --- a/drivers/mtd/nand/raw/nand_bch.c +++ b/drivers/mtd/nand/raw/nand_bch.c @@ -130,7 +130,7 @@ struct nand_bch_control *nand_bch_init(struct mtd_info *mtd) if (!nbc) goto fail; - nbc->bch = bch_init(m, t, 0); + nbc->bch = bch_init(m, t, 0, false); if (!nbc->bch) goto fail; diff --git a/include/linux/bch.h b/include/linux/bch.h index 9c35e7cd5890..85fdce83d4e2 100644 --- a/include/linux/bch.h +++ b/include/linux/bch.h @@ -33,6 +33,7 @@ * @cache: log-based polynomial representation buffer * @elp: error locator polynomial * @poly_2t: temporary polynomials of degree 2t + * @swap_bits: swap bits within data and syndrome bytes */ struct bch_control { unsigned int m; @@ -51,9 +52,11 @@ struct bch_control { int *cache; struct gf_poly *elp; struct gf_poly *poly_2t[4]; + bool swap_bits; }; -struct bch_control *bch_init(int m, int t, unsigned int prim_poly); +struct bch_control *bch_init(int m, int t, unsigned int prim_poly, + bool swap_bits); void bch_free(struct bch_control *bch); diff --git a/lib/bch.c b/lib/bch.c index 1091841ac716..7c031ee8b93b 100644 --- a/lib/bch.c +++ b/lib/bch.c @@ -114,6 +114,49 @@ struct gf_poly_deg1 { unsigned int c[2]; }; +static u8 swap_bits_table[] = { + 0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, + 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0, + 0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, + 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8, + 0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, + 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4, + 0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, + 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc, + 0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, + 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2, + 0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, + 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa, + 0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, + 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6, + 0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, + 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe, + 0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1, + 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1, + 0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, + 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9, + 0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5, + 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5, + 0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed, + 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd, + 0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, + 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3, + 0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb, + 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb, + 0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7, + 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7, + 0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, + 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff, +}; + +static u8 swap_bits(struct bch_control *bch, u8 in) +{ + if (!bch->swap_bits) + return in; + + return swap_bits_table[in]; +} + /* * same as bch_encode(), but process input data one byte at a time */ @@ -126,7 +169,9 @@ static void bch_encode_unaligned(struct bch_control *bch, const int l = BCH_ECC_WORDS(bch)-1; while (len--) { - p = bch->mod8_tab + (l+1)*(((ecc[0] >> 24)^(*data++)) & 0xff); + u8 tmp = swap_bits(bch, *data++); + + p = bch->mod8_tab + (l+1)*(((ecc[0] >> 24)^(tmp)) & 0xff); for (i = 0; i < l; i++) ecc[i] = ((ecc[i] << 8)|(ecc[i+1] >> 24))^(*p++); @@ -145,10 +190,16 @@ static void load_ecc8(struct bch_control *bch, uint32_t *dst, unsigned int i, nwords = BCH_ECC_WORDS(bch)-1; for (i = 0; i < nwords; i++, src += 4) - dst[i] = (src[0] << 24)|(src[1] << 16)|(src[2] << 8)|src[3]; + dst[i] = ((u32)swap_bits(bch, src[0]) << 24) | + ((u32)swap_bits(bch, src[1]) << 16) | + ((u32)swap_bits(bch, src[2]) << 8) | + swap_bits(bch, src[3]); memcpy(pad, src, BCH_ECC_BYTES(bch)-4*nwords); - dst[nwords] = (pad[0] << 24)|(pad[1] << 16)|(pad[2] << 8)|pad[3]; + dst[nwords] = ((u32)swap_bits(bch, pad[0]) << 24) | + ((u32)swap_bits(bch, pad[1]) << 16) | + ((u32)swap_bits(bch, pad[2]) << 8) | + swap_bits(bch, pad[3]); } /* @@ -161,15 +212,15 @@ static void store_ecc8(struct bch_control *bch, uint8_t *dst, unsigned int i, nwords = BCH_ECC_WORDS(bch)-1; for (i = 0; i < nwords; i++) { - *dst++ = (src[i] >> 24); - *dst++ = (src[i] >> 16) & 0xff; - *dst++ = (src[i] >> 8) & 0xff; - *dst++ = (src[i] >> 0) & 0xff; + *dst++ = swap_bits(bch, src[i] >> 24); + *dst++ = swap_bits(bch, src[i] >> 16); + *dst++ = swap_bits(bch, src[i] >> 8); + *dst++ = swap_bits(bch, src[i]); } - pad[0] = (src[nwords] >> 24); - pad[1] = (src[nwords] >> 16) & 0xff; - pad[2] = (src[nwords] >> 8) & 0xff; - pad[3] = (src[nwords] >> 0) & 0xff; + pad[0] = swap_bits(bch, src[nwords] >> 24); + pad[1] = swap_bits(bch, src[nwords] >> 16); + pad[2] = swap_bits(bch, src[nwords] >> 8); + pad[3] = swap_bits(bch, src[nwords]); memcpy(dst, pad, BCH_ECC_BYTES(bch)-4*nwords); } @@ -240,7 +291,13 @@ void bch_encode(struct bch_control *bch, const uint8_t *data, */ while (mlen--) { /* input data is read in big-endian format */ - w = r[0]^cpu_to_be32(*pdata++); + w = cpu_to_be32(*pdata++); + if (bch->swap_bits) + w = (u32)swap_bits(bch, w) | + ((u32)swap_bits(bch, w >> 8) << 8) | + ((u32)swap_bits(bch, w >> 16) << 16) | + ((u32)swap_bits(bch, w >> 24) << 24); + w ^= r[0]; p0 = tab0 + (l+1)*((w >> 0) & 0xff); p1 = tab1 + (l+1)*((w >> 8) & 0xff); p2 = tab2 + (l+1)*((w >> 16) & 0xff); @@ -1048,7 +1105,9 @@ int bch_decode(struct bch_control *bch, const uint8_t *data, unsigned int len, break; } errloc[i] = nbits-1-errloc[i]; - errloc[i] = (errloc[i] & ~7)|(7-(errloc[i] & 7)); + if (!bch->swap_bits) + errloc[i] = (errloc[i] & ~7) | + (7-(errloc[i] & 7)); } } return (err >= 0) ? err : -EBADMSG; @@ -1240,6 +1299,7 @@ finish: * @m: Galois field order, should be in the range 5-15 * @t: maximum error correction capability, in bits * @prim_poly: user-provided primitive polynomial (or 0 to use default) + * @swap_bits: swap bits within data and syndrome bytes * * Returns: * a newly allocated BCH control structure if successful, NULL otherwise @@ -1256,7 +1316,8 @@ finish: * BCH control structure, ecc length in bytes is given by member @ecc_bytes of * the structure. */ -struct bch_control *bch_init(int m, int t, unsigned int prim_poly) +struct bch_control *bch_init(int m, int t, unsigned int prim_poly, + bool swap_bits) { int err = 0; unsigned int i, words; @@ -1321,6 +1382,7 @@ struct bch_control *bch_init(int m, int t, unsigned int prim_poly) bch->syn = bch_alloc(2*t*sizeof(*bch->syn), &err); bch->cache = bch_alloc(2*t*sizeof(*bch->cache), &err); bch->elp = bch_alloc((t+1)*sizeof(struct gf_poly_deg1), &err); + bch->swap_bits = swap_bits; for (i = 0; i < ARRAY_SIZE(bch->poly_2t); i++) bch->poly_2t[i] = bch_alloc(GF_POLY_SZ(2*t), &err); -- cgit v1.2.3-70-g09d2