Commit b491da72 authored by Pekon Gupta's avatar Pekon Gupta Committed by Brian Norris
Browse files

mtd: nand: omap: clean-up ecc layout for BCH ecc schemes 



In current implementation omap3_init_bch_tail() is a common function to
define ecc layout for different BCHx ecc schemes.This patch:
(1) removes omap3_init_bch_tail() and defines ecc layout for individual
    ecc-schemes along with populating their nand_chip->ecc data in
    omap_nand_probe(). This improves the readability and scalability of
    code for add new ecc schemes in future.
(2) removes 'struct nand_bbt_descr bb_descrip_flashbased' because default
    nand_bbt_descr in nand_bbt.c matches the same (.len=1 for x8 devices).
(3) add the check to see if NAND device has enough OOB/Spare bytes to
    store ECC signature of whole page, as defined by ecc-scheme.

Signed-off-by: default avatarPekon Gupta <pekon@ti.com>
Tested-by: default avatarEzequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent a919e511

drivers/mtd/nand/omap2.c

+62 −99
Original line number Diff line number Diff line
@@ -139,6 +139,7 @@ 
#define BCH_ECC_SIZE0		0x0	/* ecc_size0 = 0, no oob protection */

#define BCH_ECC_SIZE1		0x20	/* ecc_size1 = 32 */



#define BADBLOCK_MARKER_LENGTH		2

#define OMAP_ECC_BCH8_POLYNOMIAL	0x201b



#ifdef CONFIG_MTD_NAND_OMAP_BCH
@@ -149,17 +150,6 @@ static u_char bch4_vector[] = {0x00, 0x6b, 0x31, 0xdd, 0x41, 0xbc, 0x10}; 


/* oob info generated runtime depending on ecc algorithm and layout selected */

static struct nand_ecclayout omap_oobinfo;

/* Define some generic bad / good block scan pattern which are used

 * while scanning a device for factory marked good / bad blocks

 */

static uint8_t scan_ff_pattern[] = { 0xff };

static struct nand_bbt_descr bb_descrip_flashbased = {

	.options = NAND_BBT_SCANALLPAGES,

	.offs = 0,

	.len = 1,

	.pattern = scan_ff_pattern,

};





struct omap_nand_info {

	struct nand_hw_control		controller;
@@ -184,7 +174,6 @@ struct omap_nand_info { 
	struct gpmc_nand_regs		reg;

	/* fields specific for BCHx_HW ECC scheme */

	struct bch_control             *bch;

	struct nand_ecclayout           ecclayout;

	bool				is_elm_used;

	struct device			*elm_dev;

	struct device_node		*of_node;
@@ -1686,65 +1675,8 @@ static void omap3_free_bch(struct mtd_info *mtd) 
	}

}



/**

 * omap3_init_bch_tail - Build an oob layout for BCH ECC correction.

 * @mtd: MTD device structure

 */

static int omap3_init_bch_tail(struct mtd_info *mtd)

{

	int i, steps, offset;

	struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,

						   mtd);

	struct nand_ecclayout *layout = &info->ecclayout;



	/* build oob layout */

	steps = mtd->writesize/info->nand.ecc.size;

	layout->eccbytes = steps*info->nand.ecc.bytes;



	/* do not bother creating special oob layouts for small page devices */

	if (mtd->oobsize < 64) {

		pr_err("BCH ecc is not supported on small page devices\n");

		goto fail;

	}



	/* reserve 2 bytes for bad block marker */

	if (layout->eccbytes+2 > mtd->oobsize) {

		pr_err("no oob layout available for oobsize %d eccbytes %u\n",

		       mtd->oobsize, layout->eccbytes);

		goto fail;

	}



	/* ECC layout compatible with RBL for BCH8 */

	if (info->is_elm_used && (info->nand.ecc.bytes == BCH8_SIZE))

		offset = 2;

	else

		offset = mtd->oobsize - layout->eccbytes;



	/* put ecc bytes at oob tail */

	for (i = 0; i < layout->eccbytes; i++)

		layout->eccpos[i] = offset + i;



	if (info->is_elm_used && (info->nand.ecc.bytes == BCH8_SIZE))

		layout->oobfree[0].offset = 2 + layout->eccbytes * steps;

	else

		layout->oobfree[0].offset = 2;



	layout->oobfree[0].length = mtd->oobsize-2-layout->eccbytes;

	info->nand.ecc.layout = layout;



	if (!(info->nand.options & NAND_BUSWIDTH_16))

		info->nand.badblock_pattern = &bb_descrip_flashbased;

	return 0;

fail:

	omap3_free_bch(mtd);

	return -1;

}



#else

static int omap3_init_bch_tail(struct mtd_info *mtd)

{

	return -1;

}



static void omap3_free_bch(struct mtd_info *mtd)

{

}
@@ -1756,8 +1688,9 @@ static int omap_nand_probe(struct platform_device *pdev) 
	struct omap_nand_platform_data	*pdata;

	struct mtd_info			*mtd;

	struct nand_chip		*nand_chip;

	struct nand_ecclayout		*ecclayout;

	int				err;

	int				i, offset;

	int				i;

	dma_cap_mask_t			mask;

	unsigned			sig;

	struct resource			*res;
@@ -1840,6 +1773,13 @@ static int omap_nand_probe(struct platform_device *pdev) 
		goto out_release_mem_region;

	}



	/* check for small page devices */

	if ((mtd->oobsize < 64) && (pdata->ecc_opt != OMAP_ECC_HAM1_CODE_HW)) {

		pr_err("small page devices are not supported\n");

		err = -EINVAL;

		goto out_release_mem_region;

	}



	/* re-populate low-level callbacks based on xfer modes */

	switch (pdata->xfer_type) {

	case NAND_OMAP_PREFETCH_POLLED:
@@ -1931,6 +1871,8 @@ static int omap_nand_probe(struct platform_device *pdev) 
	}



	/* populate MTD interface based on ECC scheme */

	nand_chip->ecc.layout	= &omap_oobinfo;

	ecclayout		= &omap_oobinfo;

	switch (pdata->ecc_opt) {

	case OMAP_ECC_HAM1_CODE_HW:

		pr_info("nand: using OMAP_ECC_HAM1_CODE_HW\n");
@@ -1941,6 +1883,16 @@ static int omap_nand_probe(struct platform_device *pdev) 
		nand_chip->ecc.calculate        = omap_calculate_ecc;

		nand_chip->ecc.hwctl            = omap_enable_hwecc;

		nand_chip->ecc.correct          = omap_correct_data;

		/* define ECC layout */

		ecclayout->eccbytes		= nand_chip->ecc.bytes *

							(mtd->writesize /

							nand_chip->ecc.size);

		if (nand_chip->options & NAND_BUSWIDTH_16)

			ecclayout->eccpos[0]	= BADBLOCK_MARKER_LENGTH;

		else

			ecclayout->eccpos[0]	= 1;

		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +

							ecclayout->eccbytes;

		break;



	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
@@ -1953,6 +1905,13 @@ static int omap_nand_probe(struct platform_device *pdev) 
		nand_chip->ecc.hwctl		= omap3_enable_hwecc_bch;

		nand_chip->ecc.correct		= omap3_correct_data_bch;

		nand_chip->ecc.calculate	= omap3_calculate_ecc_bch4;

		/* define ECC layout */

		ecclayout->eccbytes		= nand_chip->ecc.bytes *

							(mtd->writesize /

							nand_chip->ecc.size);

		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;

		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +

							ecclayout->eccbytes;

		/* software bch library is used for locating errors */

		info->bch = init_bch(nand_chip->ecc.bytes,

					nand_chip->ecc.strength,
@@ -1981,6 +1940,13 @@ static int omap_nand_probe(struct platform_device *pdev) 
		nand_chip->ecc.calculate	= omap3_calculate_ecc_bch;

		nand_chip->ecc.read_page	= omap_read_page_bch;

		nand_chip->ecc.write_page	= omap_write_page_bch;

		/* define ECC layout */

		ecclayout->eccbytes		= nand_chip->ecc.bytes *

							(mtd->writesize /

							nand_chip->ecc.size);

		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;

		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +

							ecclayout->eccbytes;

		/* This ECC scheme requires ELM H/W block */

		if (is_elm_present(info, pdata->elm_of_node, BCH4_ECC) < 0) {

			pr_err("nand: error: could not initialize ELM\n");
@@ -2004,6 +1970,13 @@ static int omap_nand_probe(struct platform_device *pdev) 
		nand_chip->ecc.hwctl		= omap3_enable_hwecc_bch;

		nand_chip->ecc.correct		= omap3_correct_data_bch;

		nand_chip->ecc.calculate	= omap3_calculate_ecc_bch8;

		/* define ECC layout */

		ecclayout->eccbytes		= nand_chip->ecc.bytes *

							(mtd->writesize /

							nand_chip->ecc.size);

		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;

		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +

							ecclayout->eccbytes;

		/* software bch library is used for locating errors */

		info->bch = init_bch(nand_chip->ecc.bytes,

					nand_chip->ecc.strength,
@@ -2038,6 +2011,13 @@ static int omap_nand_probe(struct platform_device *pdev) 
			pr_err("nand: error: could not initialize ELM\n");

			goto out_release_mem_region;

		}

		/* define ECC layout */

		ecclayout->eccbytes		= nand_chip->ecc.bytes *

							(mtd->writesize /

							nand_chip->ecc.size);

		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;

		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +

							ecclayout->eccbytes;

		break;

#else

		pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
@@ -2051,35 +2031,18 @@ static int omap_nand_probe(struct platform_device *pdev) 
		goto out_release_mem_region;

	}



	/* rom code layout */

	if (pdata->ecc_opt == OMAP_ECC_HAM1_CODE_HW) {



		if (nand_chip->options & NAND_BUSWIDTH_16) {

			offset = 2;

		} else {

			offset = 1;

			nand_chip->badblock_pattern = &bb_descrip_flashbased;

		}

		omap_oobinfo.eccbytes = 3 * (mtd->writesize / 512);

		for (i = 0; i < omap_oobinfo.eccbytes; i++)

			omap_oobinfo.eccpos[i] = i+offset;



		omap_oobinfo.oobfree->offset = offset + omap_oobinfo.eccbytes;

		omap_oobinfo.oobfree->length = mtd->oobsize -

					(offset + omap_oobinfo.eccbytes);



		nand_chip->ecc.layout = &omap_oobinfo;

	} else if ((pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW) ||

		   (pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW_DETECTION_SW) ||

		   (pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW_DETECTION_SW) ||

		   (pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW)) {

		/* build OOB layout for BCH ECC correction */

		err = omap3_init_bch_tail(mtd);

		if (err) {

	/* populate remaining ECC layout data */

	ecclayout->oobfree->length = mtd->oobsize - (BADBLOCK_MARKER_LENGTH +

							ecclayout->eccbytes);

	for (i = 1; i < ecclayout->eccbytes; i++)

		ecclayout->eccpos[i] = ecclayout->eccpos[0] + i;

	/* check if NAND device's OOB is enough to store ECC signatures */

	if (mtd->oobsize < (ecclayout->eccbytes + BADBLOCK_MARKER_LENGTH)) {

		pr_err("not enough OOB bytes required = %d, available=%d\n",

					   ecclayout->eccbytes, mtd->oobsize);

		err = -EINVAL;

		goto out_release_mem_region;

	}

	}



	/* second phase scan */

	if (nand_scan_tail(mtd)) {

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