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mtd: fsmc: Improve the fsmc_correct_data() routine

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This patch improves the error correction routine for bch8
- Loop only up to number of errors detected
- Improve the error index calculation procedure

Additionally, it also renames the "correct" routine to indicate that it is bch8
specific

Signed-off-by: Armando Visconti <armando.visconti@st.com>
Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Armando Visconti 2012-03-07 17:00:54 +05:30 committed by David Woodhouse
parent a612c2ae48
commit 753e0139e5
1 changed files with 16 additions and 20 deletions
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36
drivers/mtd/nand/fsmc_nand.c
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@ -587,7 +587,7 @@ static int fsmc_read_page_hwecc(struct mtd_info *mtd, struct nand_chip *chip,
}
/*
* fsmc_correct_data
* fsmc_bch8_correct_data
* @mtd: mtd info structure
* @dat: buffer of read data
* @read_ecc: ecc read from device spare area
@ -596,7 +596,7 @@ static int fsmc_read_page_hwecc(struct mtd_info *mtd, struct nand_chip *chip,
* calc_ecc is a 104 bit information containing maximum of 8 error
* offset informations of 13 bits each in 512 bytes of read data.
*/
static int fsmc_correct_data(struct mtd_info *mtd, uint8_t *dat,
static int fsmc_bch8_correct_data(struct mtd_info *mtd, uint8_t *dat,
uint8_t *read_ecc, uint8_t *calc_ecc)
{
struct fsmc_nand_data *host = container_of(mtd,
@ -605,8 +605,8 @@ static int fsmc_correct_data(struct mtd_info *mtd, uint8_t *dat,
struct fsmc_regs *regs = host->regs_va;
unsigned int bank = host->bank;
uint32_t err_idx[8];
uint64_t ecc_data[2];
uint32_t num_err, i;
uint32_t ecc1, ecc2, ecc3, ecc4;
num_err = (readl(&regs->bank_regs[bank].sts) >> 10) & 0xF;
@ -642,9 +642,6 @@ static int fsmc_correct_data(struct mtd_info *mtd, uint8_t *dat,
return -EBADMSG;
}
/* The calculated ecc is actually the correction index in data */
memcpy(ecc_data, calc_ecc, chip->ecc.bytes);
/*
* ------------------- calc_ecc[] bit wise -----------|--13 bits--|
* |---idx[7]--|--.....-----|---idx[2]--||---idx[1]--||---idx[0]--|
@ -654,20 +651,19 @@ static int fsmc_correct_data(struct mtd_info *mtd, uint8_t *dat,
* uint64_t array and error offset indexes are populated in err_idx
* array
*/
for (i = 0; i < 8; i++) {
if (i == 4) {
err_idx[4] = ((ecc_data[1] & 0x1) << 12) | ecc_data[0];
ecc_data[1] >>= 1;
continue;
}
err_idx[i] = (ecc_data[i/4] & 0x1FFF);
ecc_data[i/4] >>= 13;
}
ecc1 = readl(&regs->bank_regs[bank].ecc1);
ecc2 = readl(&regs->bank_regs[bank].ecc2);
ecc3 = readl(&regs->bank_regs[bank].ecc3);
ecc4 = readl(&regs->bank_regs[bank].sts);
num_err = (readl(&regs->bank_regs[bank].sts) >> 10) & 0xF;
if (num_err == 0xF)
return -EBADMSG;
err_idx[0] = (ecc1 >> 0) & 0x1FFF;
err_idx[1] = (ecc1 >> 13) & 0x1FFF;
err_idx[2] = (((ecc2 >> 0) & 0x7F) << 6) | ((ecc1 >> 26) & 0x3F);
err_idx[3] = (ecc2 >> 7) & 0x1FFF;
err_idx[4] = (((ecc3 >> 0) & 0x1) << 12) | ((ecc2 >> 20) & 0xFFF);
err_idx[5] = (ecc3 >> 1) & 0x1FFF;
err_idx[6] = (ecc3 >> 14) & 0x1FFF;
err_idx[7] = (((ecc4 >> 16) & 0xFF) << 5) | ((ecc3 >> 27) & 0x1F);
i = 0;
while (num_err--) {
@ -829,7 +825,7 @@ static int __init fsmc_nand_probe(struct platform_device *pdev)
if (AMBA_REV_BITS(host->pid) >= 8) {
nand->ecc.read_page = fsmc_read_page_hwecc;
nand->ecc.calculate = fsmc_read_hwecc_ecc4;
nand->ecc.correct = fsmc_correct_data;
nand->ecc.correct = fsmc_bch8_correct_data;
nand->ecc.bytes = 13;
} else {
nand->ecc.calculate = fsmc_read_hwecc_ecc1;