diff options
Diffstat (limited to 'lib/bch.c')
| -rw-r--r-- | lib/bch.c | 90 |
1 files changed, 76 insertions, 14 deletions
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); |