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Commit 3ec7cb36 authored by Chris Packham's avatar Chris Packham Committed by Miquel Raynal
Browse files

mtd: rawnand: micron: support 8/512 on-die ECC 



Micron MT29F1G08ABAFAWP-ITE:F supports an on-die ECC with 8 bits
per 512 bytes. Add support for this combination.

Signed-off-by: default avatarChris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
parent dbc44edb

drivers/mtd/nand/raw/nand_micron.c

+131 −30
Original line number Diff line number Diff line
@@ -18,10 +18,30 @@ 
#include <linux/mtd/rawnand.h>



/*

 * Special Micron status bit that indicates when the block has been

 * corrected by on-die ECC and should be rewritten

 * Special Micron status bit 3 indicates that the block has been

 * corrected by on-die ECC and should be rewritten.

 */

#define NAND_STATUS_WRITE_RECOMMENDED	BIT(3)

#define NAND_ECC_STATUS_WRITE_RECOMMENDED	BIT(3)



/*

 * On chips with 8-bit ECC and additional bit can be used to distinguish

 * cases where a errors were corrected without needing a rewrite

 *

 * Bit 4 Bit 3 Bit 0 Description

 * ----- ----- ----- -----------

 * 0     0     0     No Errors

 * 0     0     1     Multiple uncorrected errors

 * 0     1     0     4 - 6 errors corrected, recommend rewrite

 * 0     1     1     Reserved

 * 1     0     0     1 - 3 errors corrected

 * 1     0     1     Reserved

 * 1     1     0     7 - 8 errors corrected, recommend rewrite

 */

#define NAND_ECC_STATUS_MASK		(BIT(4) | BIT(3) | BIT(0))

#define NAND_ECC_STATUS_UNCORRECTABLE	BIT(0)

#define NAND_ECC_STATUS_4_6_CORRECTED	BIT(3)

#define NAND_ECC_STATUS_1_3_CORRECTED	BIT(4)

#define NAND_ECC_STATUS_7_8_CORRECTED	(BIT(4) | BIT(3))



struct nand_onfi_vendor_micron {

	u8 two_plane_read;
@@ -74,7 +94,8 @@ static int micron_nand_onfi_init(struct nand_chip *chip) 
	return 0;

}



static int micron_nand_on_die_ooblayout_ecc(struct mtd_info *mtd, int section,

static int micron_nand_on_die_4_ooblayout_ecc(struct mtd_info *mtd,

					      int section,

					      struct mtd_oob_region *oobregion)

{

	if (section >= 4)
@@ -86,7 +107,8 @@ static int micron_nand_on_die_ooblayout_ecc(struct mtd_info *mtd, int section, 
	return 0;

}



static int micron_nand_on_die_ooblayout_free(struct mtd_info *mtd, int section,

static int micron_nand_on_die_4_ooblayout_free(struct mtd_info *mtd,

					       int section,

					       struct mtd_oob_region *oobregion)

{

	if (section >= 4)
@@ -98,9 +120,44 @@ static int micron_nand_on_die_ooblayout_free(struct mtd_info *mtd, int section, 
	return 0;

}



static const struct mtd_ooblayout_ops micron_nand_on_die_ooblayout_ops = {

	.ecc = micron_nand_on_die_ooblayout_ecc,

	.free = micron_nand_on_die_ooblayout_free,

static const struct mtd_ooblayout_ops micron_nand_on_die_4_ooblayout_ops = {

	.ecc = micron_nand_on_die_4_ooblayout_ecc,

	.free = micron_nand_on_die_4_ooblayout_free,

};



static int micron_nand_on_die_8_ooblayout_ecc(struct mtd_info *mtd,

					      int section,

					      struct mtd_oob_region *oobregion)

{

	struct nand_chip *chip = mtd_to_nand(mtd);



	if (section)

		return -ERANGE;



	oobregion->offset = mtd->oobsize - chip->ecc.total;

	oobregion->length = chip->ecc.total;



	return 0;

}



static int micron_nand_on_die_8_ooblayout_free(struct mtd_info *mtd,

					       int section,

					       struct mtd_oob_region *oobregion)

{

	struct nand_chip *chip = mtd_to_nand(mtd);



	if (section)

		return -ERANGE;



	oobregion->offset = 2;

	oobregion->length = mtd->oobsize - chip->ecc.total - 2;



	return 0;

}



static const struct mtd_ooblayout_ops micron_nand_on_die_8_ooblayout_ops = {

	.ecc = micron_nand_on_die_8_ooblayout_ecc,

	.free = micron_nand_on_die_8_ooblayout_free,

};



static int micron_nand_on_die_ecc_setup(struct nand_chip *chip, bool enable)
@@ -113,6 +170,55 @@ static int micron_nand_on_die_ecc_setup(struct nand_chip *chip, bool enable) 
	return nand_set_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);

}



static int micron_nand_on_die_ecc_status_4(struct nand_chip *chip, u8 status)

{

	struct mtd_info *mtd = nand_to_mtd(chip);



	/*

	 * The internal ECC doesn't tell us the number of bitflips

	 * that have been corrected, but tells us if it recommends to

	 * rewrite the block. If it's the case, then we pretend we had

	 * a number of bitflips equal to the ECC strength, which will

	 * hint the NAND core to rewrite the block.

	 */

	if (status & NAND_STATUS_FAIL) {

		mtd->ecc_stats.failed++;

	} else if (status & NAND_ECC_STATUS_WRITE_RECOMMENDED) {

		mtd->ecc_stats.corrected += chip->ecc.strength;

		return chip->ecc.strength;

	}



	return 0;

}



static int micron_nand_on_die_ecc_status_8(struct nand_chip *chip, u8 status)

{

	struct mtd_info *mtd = nand_to_mtd(chip);



	/*

	 * With 8/512 we have more information but still don't know precisely

	 * how many bit-flips were seen.

	 */

	switch (status & NAND_ECC_STATUS_MASK) {

	case NAND_ECC_STATUS_UNCORRECTABLE:

		mtd->ecc_stats.failed++;

		return 0;

	case NAND_ECC_STATUS_1_3_CORRECTED:

		mtd->ecc_stats.corrected += 3;

		return 3;

	case NAND_ECC_STATUS_4_6_CORRECTED:

		mtd->ecc_stats.corrected += 6;

		/* rewrite recommended */

		return 6;

	case NAND_ECC_STATUS_7_8_CORRECTED:

		mtd->ecc_stats.corrected += 8;

		/* rewrite recommended */

		return 8;

	default:

		return 0;

	}

}



static int

micron_nand_read_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip,

				 uint8_t *buf, int oob_required,
@@ -137,19 +243,10 @@ micron_nand_read_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip, 
	if (ret)

		goto out;



	if (status & NAND_STATUS_FAIL) {

		mtd->ecc_stats.failed++;

	} else if (status & NAND_STATUS_WRITE_RECOMMENDED) {

		/*

		 * The internal ECC doesn't tell us the number of bitflips

		 * that have been corrected, but tells us if it recommends to

		 * rewrite the block. If it's the case, then we pretend we had

		 * a number of bitflips equal to the ECC strength, which will

		 * hint the NAND core to rewrite the block.

		 */

		mtd->ecc_stats.corrected += chip->ecc.strength;

		max_bitflips = chip->ecc.strength;

	}

	if (chip->ecc.strength == 4)

		max_bitflips = micron_nand_on_die_ecc_status_4(chip, status);

	else

		max_bitflips = micron_nand_on_die_ecc_status_8(chip, status);



	ret = nand_read_data_op(chip, buf, mtd->writesize, false);

	if (!ret && oob_required)
@@ -254,10 +351,9 @@ static int micron_supports_on_die_ecc(struct nand_chip *chip) 
		return MICRON_ON_DIE_MANDATORY;



	/*

	 * Some Micron NANDs have an on-die ECC of 4/512, some other

	 * 8/512. We only support the former.

	 * We only support on-die ECC of 4/512 or 8/512

	 */

	if (chip->ecc_strength_ds != 4)

	if  (chip->ecc_strength_ds != 4 && chip->ecc_strength_ds != 8)

		return MICRON_ON_DIE_UNSUPPORTED;



	return MICRON_ON_DIE_SUPPORTED;
@@ -289,16 +385,21 @@ static int micron_nand_init(struct nand_chip *chip) 
			return -EINVAL;

		}



		chip->ecc.bytes = 8;

		if (chip->ecc_strength_ds == 4)

			mtd_set_ooblayout(mtd,

					  &micron_nand_on_die_4_ooblayout_ops);

		else

			mtd_set_ooblayout(mtd,

					  &micron_nand_on_die_8_ooblayout_ops);



		chip->ecc.bytes = chip->ecc_strength_ds * 2;

		chip->ecc.size = 512;

		chip->ecc.strength = 4;

		chip->ecc.strength = chip->ecc_strength_ds;

		chip->ecc.algo = NAND_ECC_BCH;

		chip->ecc.read_page = micron_nand_read_page_on_die_ecc;

		chip->ecc.write_page = micron_nand_write_page_on_die_ecc;

		chip->ecc.read_page_raw = nand_read_page_raw;

		chip->ecc.write_page_raw = nand_write_page_raw;



		mtd_set_ooblayout(mtd, &micron_nand_on_die_ooblayout_ops);

	}



	return 0;