* 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
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 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)
{
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++);
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]);
}
/*
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);
}
/**
- * 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
* 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;
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;
}
*/
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);
/* 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)
{
#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
* 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
* 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)
{
/* 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);
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;
}
-EXPORT_SYMBOL_GPL(decode_bch);
+EXPORT_SYMBOL_GPL(bch_decode);
/*
* generate Galois field lookup tables
}
/**
- * 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)
+ * @swap_bits: swap bits within data and syndrome bytes
*
* Returns:
* a newly allocated BCH control structure if successful, NULL otherwise
*
* 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,
+ bool swap_bits)
{
int err = 0;
unsigned int i, words;
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);
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;
kfree(bch);
}
}
-EXPORT_SYMBOL_GPL(free_bch);
+EXPORT_SYMBOL_GPL(bch_free);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ivan Djelic <ivan.djelic@parrot.com>");
projects / linux-2.6-microblaze.git / blobdiff