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Commit 753e0139 authored by Armando Visconti's avatar Armando Visconti Committed by David Woodhouse
Browse files

mtd: fsmc: Improve the fsmc_correct_data() routine 



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: default avatarArmando Visconti <armando.visconti@st.com>
Signed-off-by: default avatarVipin Kumar <vipin.kumar@st.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent a612c2ae

drivers/mtd/nand/fsmc_nand.c

+17 −21
Original line number Diff line number Diff line
@@ -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;

	}



	num_err = (readl(&regs->bank_regs[bank].sts) >> 10) & 0xF;



	if (num_err == 0xF)

		return -EBADMSG;

	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);



	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;