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-rw-r--r--lib/bch.c122
1 files changed, 75 insertions, 47 deletions
diff --git a/lib/bch.c b/lib/bch.c
index 5db6d3a4c8a6..5f71fd76eca8 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
@@ -71,6 +71,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/bitops.h>
+#include <linux/bitrev.h>
#include <asm/byteorder.h>
#include <linux/bch.h>
@@ -102,7 +103,7 @@
*/
struct gf_poly {
unsigned int deg; /* polynomial degree */
- unsigned int c[0]; /* polynomial terms */
+ unsigned int c[]; /* polynomial terms */
};
/* given its degree, compute a polynomial size in bytes */
@@ -114,10 +115,18 @@ struct gf_poly_deg1 {
unsigned int c[2];
};
+static u8 swap_bits(struct bch_control *bch, u8 in)
+{
+ if (!bch->swap_bits)
+ return in;
+
+ return bitrev8(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)
{
@@ -126,7 +135,9 @@ static void encode_bch_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 +156,16 @@ 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]);
}
/*
@@ -161,20 +178,20 @@ 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);
}
/**
- * 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 +204,7 @@ 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 +232,7 @@ 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;
}
@@ -240,7 +257,13 @@ void encode_bch(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);
@@ -255,13 +278,13 @@ 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)
{
@@ -527,7 +550,7 @@ static int find_affine4_roots(struct bch_control *bch, unsigned int a,
k = a_log(bch, a);
rows[0] = c;
- /* buid linear system to solve X^4+aX^2+bX+c = 0 */
+ /* build linear system to solve X^4+aX^2+bX+c = 0 */
for (i = 0; i < m; i++) {
rows[i+1] = bch->a_pow_tab[4*i]^
(a ? bch->a_pow_tab[mod_s(bch, k)] : 0)^
@@ -952,7 +975,7 @@ 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 +989,22 @@ 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 +1016,7 @@ 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 +1035,7 @@ 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);
@@ -1048,12 +1071,14 @@ int decode_bch(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;
}
-EXPORT_SYMBOL_GPL(decode_bch);
+EXPORT_SYMBOL_GPL(bch_decode);
/*
* generate Galois field lookup tables
@@ -1236,27 +1261,29 @@ 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)
+ * @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;
@@ -1321,6 +1348,7 @@ struct bch_control *init_bch(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);
@@ -1347,16 +1375,16 @@ 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 +1405,7 @@ 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 <ivan.djelic@parrot.com>");
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-04-30 08:59:26 +0000