#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
#include <linux/mtd/nand_ecc.h>
#include <asm/byteorder.h>
#else
};
/**
- * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256-byte block
- * @mtd: MTD block structure (unused)
+ * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
+ * block
+ * @mtd: MTD block structure
* @buf: input buffer with raw data
* @code: output buffer with ECC
*/
{
int i;
const uint32_t *bp = (uint32_t *)buf;
+ /* 256 or 512 bytes/ecc */
+ const uint32_t eccsize_mult =
+ (((struct nand_chip *)mtd->priv)->ecc.size) >> 8;
uint32_t cur; /* current value in buffer */
- /* rp0..rp15 are the various accumulated parities (per byte) */
+ /* rp0..rp15..rp17 are the various accumulated parities (per byte) */
uint32_t rp0, rp1, rp2, rp3, rp4, rp5, rp6, rp7;
- uint32_t rp8, rp9, rp10, rp11, rp12, rp13, rp14, rp15;
+ uint32_t rp8, rp9, rp10, rp11, rp12, rp13, rp14, rp15, rp16;
+ uint32_t uninitialized_var(rp17); /* to make compiler happy */
uint32_t par; /* the cumulative parity for all data */
uint32_t tmppar; /* the cumulative parity for this iteration;
- for rp12 and rp14 at the end of the loop */
+ for rp12, rp14 and rp16 at the end of the
+ loop */
par = 0;
rp4 = 0;
rp10 = 0;
rp12 = 0;
rp14 = 0;
+ rp16 = 0;
/*
* The loop is unrolled a number of times;
* 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 and par
+ * needed for calculating rp12, rp14, rp16 and par
* also used as a performance improvement for rp6, rp8 and rp10
*/
- for (i = 0; i < 4; i++) {
+ for (i = 0; i < eccsize_mult << 2; i++) {
cur = *bp++;
tmppar = cur;
rp4 ^= cur;
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 back to single byte entities by shifting and
- * xoring first fold the upper and lower 16 bits,
+ * 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);
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
par &= 0xff;
/*
- * and calculate rp5..rp15
+ * 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);
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.
(invparity[rp9] << 1) |
(invparity[rp8]);
#endif
- 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;
+ 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(nand_calculate_ecc);
/**
- * nand_correct_data - [NAND Interface] Detect and correct bit error(s)
- * @mtd: MTD block structure (unused)
+ * __nand_correct_data - [NAND Interface] Detect and correct bit error(s)
* @buf: raw data read from the chip
* @read_ecc: ECC from the chip
* @calc_ecc: the ECC calculated from raw data
+ * @eccsize: data bytes per ecc step (256 or 512)
*
- * Detect and correct a 1 bit error for 256 byte block
+ * Detect and correct a 1 bit error for eccsize byte block
*/
-int nand_correct_data(struct mtd_info *mtd, unsigned char *buf,
- unsigned char *read_ecc, unsigned char *calc_ecc)
+int __nand_correct_data(unsigned char *buf,
+ unsigned char *read_ecc, unsigned char *calc_ecc,
+ unsigned int eccsize)
{
- unsigned char b0, b1, b2;
- unsigned char byte_addr, bit_addr;
+ unsigned char b0, b1, b2, bit_addr;
+ unsigned int byte_addr;
+ /* 256 or 512 bytes/ecc */
+ const uint32_t eccsize_mult = eccsize >> 8;
/*
* b0 to b2 indicate which bit is faulty (if any)
if ((((b0 ^ (b0 >> 1)) & 0x55) == 0x55) &&
(((b1 ^ (b1 >> 1)) & 0x55) == 0x55) &&
- (((b2 ^ (b2 >> 1)) & 0x54) == 0x54)) { /* single bit error */
+ ((eccsize_mult == 1 && ((b2 ^ (b2 >> 1)) & 0x54) == 0x54) ||
+ (eccsize_mult == 2 && ((b2 ^ (b2 >> 1)) & 0x55) == 0x55))) {
+ /* single bit error */
/*
- * rp15/13/11/9/7/5/3/1 indicate which byte is the faulty byte
- * cp 5/3/1 indicate the faulty bit.
+ * 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
*
* The b2 shift is there to get rid of the lowest two bits.
* We could also do addressbits[b2] >> 1 but for the
- * performace it does not make any difference
+ * performance it does not make any difference
*/
- byte_addr = (addressbits[b1] << 4) + addressbits[b0];
+ 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);
printk(KERN_ERR "uncorrectable error : ");
return -1;
}
+EXPORT_SYMBOL(__nand_correct_data);
+
+/**
+ * nand_correct_data - [NAND Interface] Detect and correct bit error(s)
+ * @mtd: MTD block structure
+ * @buf: raw data read from the chip
+ * @read_ecc: ECC from the chip
+ * @calc_ecc: the ECC calculated from raw data
+ *
+ * Detect and correct a 1 bit error for 256/512 byte block
+ */
+int nand_correct_data(struct mtd_info *mtd, unsigned char *buf,
+ unsigned char *read_ecc, unsigned char *calc_ecc)
+{
+ return __nand_correct_data(buf, read_ecc, calc_ecc,
+ ((struct nand_chip *)mtd->priv)->ecc.size);
+}
EXPORT_SYMBOL(nand_correct_data);
MODULE_LICENSE("GPL");
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff