mtd: nand: qpic-common: add defines for ECC_MODE values

Add defines for the values of the ECC_MODE field of the NAND_DEV0_ECC_CFG
register and change both the 'qcom-nandc' and 'spi-qpic-snand' drivers to
use those instead of magic numbers.

No functional changes. This is in preparation for adding 8 bit ECC strength
support for the 'spi-qpic-snand' driver.

Reviewed-by: Md Sadre Alam <quic_mdalam@quicinc.com>
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://patch.msgid.link/20250702-qpic-snand-8bit-ecc-v2-1-ae2c17a30bb7@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: juhosg

drivers/mtd/nand/raw/qcom_nandc.c

@@ -1379,7 +1379,7 @@ static int qcom_nand_attach_chip(struct nand_chip *chip)
 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
 	int cwperpage, bad_block_byte, ret;
 	bool wide_bus;
-	int ecc_mode = 1;
+	int ecc_mode = ECC_MODE_8BIT;
 
 	/* controller only supports 512 bytes data steps */
 	ecc->size = NANDC_STEP_SIZE;
@@ -1400,7 +1400,7 @@ static int qcom_nand_attach_chip(struct nand_chip *chip)
 	if (ecc->strength >= 8) {
 		/* 8 bit ECC defaults to BCH ECC on all platforms */
 		host->bch_enabled = true;
-		ecc_mode = 1;
+		ecc_mode = ECC_MODE_8BIT;
 
 		if (wide_bus) {
 			host->ecc_bytes_hw = 14;
@@ -1420,7 +1420,7 @@ static int qcom_nand_attach_chip(struct nand_chip *chip)
 		if (nandc->props->ecc_modes & ECC_BCH_4BIT) {
 			/* BCH */
 			host->bch_enabled = true;
-			ecc_mode = 0;
+			ecc_mode = ECC_MODE_4BIT;
 
 			if (wide_bus) {
 				host->ecc_bytes_hw = 8;

drivers/spi/spi-qpic-snand.c

@@ -343,7 +343,7 @@ static int qcom_spi_ecc_init_ctx_pipelined(struct nand_device *nand)
 			       FIELD_PREP(ECC_SW_RESET, 0) |
 			       FIELD_PREP(ECC_NUM_DATA_BYTES_MASK, ecc_cfg->cw_data) |
 			       FIELD_PREP(ECC_FORCE_CLK_OPEN, 1) |
-			       FIELD_PREP(ECC_MODE_MASK, 0) |
+			       FIELD_PREP(ECC_MODE_MASK, ECC_MODE_4BIT) |
 			       FIELD_PREP(ECC_PARITY_SIZE_BYTES_BCH_MASK, ecc_cfg->ecc_bytes_hw);
 
 	ecc_cfg->ecc_buf_cfg = FIELD_PREP(NUM_STEPS_MASK, 0x203);

include/linux/mtd/nand-qpic-common.h

@@ -101,6 +101,8 @@
 #define	ECC_SW_RESET			BIT(1)
 #define	ECC_MODE			4
 #define	ECC_MODE_MASK			GENMASK(5, 4)
+#define	ECC_MODE_4BIT			0
+#define	ECC_MODE_8BIT			1
 #define	ECC_PARITY_SIZE_BYTES_BCH	8
 #define	ECC_PARITY_SIZE_BYTES_BCH_MASK	GENMASK(12, 8)
 #define	ECC_NUM_DATA_BYTES		16