Commit f5dc06fb authored by Pekon Gupta's avatar Pekon Gupta Committed by Brian Norris
Browse files

mtd: nand: omap: ecc.calculate: refactor omap_calculate_ecc_bch for BCHx_HW ecc-scheme 



OMAP NAND driver supports multiple flavours of BCH4 and BCH8 ECC algorithms.
+------+------------------------------------+---------------+---------------+
| Algo | ECC scheme                         |ECC calculation|Error detection|
+------+------------------------------------+---------------+---------------+
|      |OMAP_ECC_BCH4_CODE_HW_DETECTION_SW  |H/W (GPMC)     |S/W            |
| BCH4 |OMAP_ECC_BCH4_CODE_HW               |H/W (GPMC)     |H/W (ELM)      |
+------+------------------------------------+---------------+---------------+
|      |OMAP_ECC_BCH8_CODE_HW_DETECTION_SW  |H/W (GPMC)     |S/W            |
| BCH8 |OMAP_ECC_BCH8_CODE_HW               |H/W (GPMC)     |H/W (ELM)      |
+------+------------------------------------+---------------+---------------+

This patch refactors omap_calculate_ecc_bch() so that
 - separate out ecc-scheme specific code so that common-code can be reused
   between different implementations of same ECC algorithm.
 - new ecc-schemes can be added with ease in future.

Tested-by: default avatarStefan Roese <sr@denx.de>
Signed-off-by: default avatarPekon Gupta <pekon@ti.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent a4c7ca00

drivers/mtd/nand/omap2.c

+35 −33
Original line number Diff line number Diff line
@@ -1219,33 +1219,25 @@ static int omap3_calculate_ecc_bch8(struct mtd_info *mtd, const u_char *dat, 
 * Support calculating of BCH4/8 ecc vectors for the page

 */

static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,

					const u_char *dat, u_char *ecc_code)

					const u_char *dat, u_char *ecc_calc)

{

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

						   mtd);

	int eccbytes	= info->nand.ecc.bytes;

	struct gpmc_nand_regs	*gpmc_regs = &info->reg;

	u8 *ecc_code;

	unsigned long nsectors, bch_val1, bch_val2, bch_val3, bch_val4;

	int i, eccbchtsel;

	int i;



	nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;

	/*

	 * find BCH scheme used

	 * 0 -> BCH4

	 * 1 -> BCH8

	 */

	eccbchtsel = ((readl(info->reg.gpmc_ecc_config) >> 12) & 0x3);



	for (i = 0; i < nsectors; i++) {



		/* Read hw-computed remainder */

		bch_val1 = readl(info->reg.gpmc_bch_result0[i]);

		bch_val2 = readl(info->reg.gpmc_bch_result1[i]);

		if (eccbchtsel) {

			bch_val3 = readl(info->reg.gpmc_bch_result2[i]);

			bch_val4 = readl(info->reg.gpmc_bch_result3[i]);

		}



		if (eccbchtsel) {

			/* BCH8 ecc scheme */

		ecc_code = ecc_calc;

		switch (info->ecc_opt) {

		case OMAP_ECC_BCH8_CODE_HW:

			bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);

			bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);

			bch_val3 = readl(gpmc_regs->gpmc_bch_result2[i]);

			bch_val4 = readl(gpmc_regs->gpmc_bch_result3[i]);

			*ecc_code++ = (bch_val4 & 0xFF);

			*ecc_code++ = ((bch_val3 >> 24) & 0xFF);

			*ecc_code++ = ((bch_val3 >> 16) & 0xFF);
@@ -1259,14 +1251,10 @@ static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd, 
			*ecc_code++ = ((bch_val1 >> 16) & 0xFF);

			*ecc_code++ = ((bch_val1 >> 8) & 0xFF);

			*ecc_code++ = (bch_val1 & 0xFF);

			/*

			 * Setting 14th byte to zero to handle

			 * erased page & maintain compatibility

			 * with RBL

			 */

			*ecc_code++ = 0x0;

		} else {

			/* BCH4 ecc scheme */

			break;

		case OMAP_ECC_BCH4_CODE_HW:

			bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);

			bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);

			*ecc_code++ = ((bch_val2 >> 12) & 0xFF);

			*ecc_code++ = ((bch_val2 >> 4) & 0xFF);

			*ecc_code++ = ((bch_val2 & 0xF) << 4) |
@@ -1275,12 +1263,26 @@ static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd, 
			*ecc_code++ = ((bch_val1 >> 12) & 0xFF);

			*ecc_code++ = ((bch_val1 >> 4) & 0xFF);

			*ecc_code++ = ((bch_val1 & 0xF) << 4);

			/*

			 * Setting 8th byte to zero to handle

			 * erased page

			 */

			*ecc_code++ = 0x0;

			break;

		default:

			return -EINVAL;

		}



		/* ECC scheme specific syndrome customizations */

		switch (info->ecc_opt) {

		case OMAP_ECC_BCH4_CODE_HW:

			/* Set  8th ECC byte as 0x0 for ROM compatibility */

			ecc_calc[eccbytes - 1] = 0x0;

			break;

		case OMAP_ECC_BCH8_CODE_HW:

			/* Set 14th ECC byte as 0x0 for ROM compatibility */

			ecc_calc[eccbytes - 1] = 0x0;

			break;

		default:

			return -EINVAL;

		}



	ecc_calc += eccbytes;

	}



	return 0;

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