Rectify Bluefin NAND on-die ECC support

drivers/mtd/nand/raw/nand_micron.c

@@ -365,6 +365,46 @@ micron_nand_read_page_on_die_ecc(struct nand_chip *chip, uint8_t *buf,
 	return ret ? ret : max_bitflips;
 }
 
+static int
+micron_nand_read_subpage_on_die_ecc(struct nand_chip *chip, uint32_t data_offs,
+				    uint32_t readlen, uint8_t *bufpoi, int page)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	u8 status;
+	int ret, max_bitflips = 0;
+
+	ret = micron_nand_on_die_ecc_setup(chip, true);
+	if (ret)
+		return ret;
+
+	ret = nand_status_op(chip, &status);
+	if (ret)
+		goto out;
+
+	ret = nand_read_page_op(chip, page, data_offs,
+				bufpoi + data_offs, readlen);
+	if (ret)
+		goto out;
+
+	ret = nand_status_op(chip, &status);
+	if (ret)
+		goto out;
+
+	if (status & NAND_STATUS_FAIL) {
+		/* uncorrected */
+		mtd->ecc_stats.failed++;
+	} else if (status & NAND_ECC_STATUS_WRITE_RECOMMENDED) {
+		/* corrected */
+		max_bitflips = mtd->bitflip_threshold;
+		mtd->ecc_stats.corrected += max_bitflips;
+	}
+
+out:
+	micron_nand_on_die_ecc_setup(chip, false);
+
+	return ret ? ret : max_bitflips;
+}
+
 static int
 micron_nand_write_page_on_die_ecc(struct nand_chip *chip, const uint8_t *buf,
 				  int oob_required, int page)
@@ -381,6 +421,15 @@ micron_nand_write_page_on_die_ecc(struct nand_chip *chip, const uint8_t *buf,
 	return ret;
 }
 
+static int
+micron_nand_write_subpage_on_die_ecc(struct nand_chip *chip,
+				     uint32_t offset, uint32_t data_len,
+				     const uint8_t *data_buf,
+				     int oob_required, int page)
+{
+	return micron_nand_write_page_on_die_ecc(chip, data_buf, oob_required, page);
+}
+
 enum {
 	/* The NAND flash doesn't support on-die ECC */
 	MICRON_ON_DIE_UNSUPPORTED,
@@ -550,7 +599,9 @@ static int micron_nand_init(struct nand_chip *chip)
 		chip->ecc.strength = requirements->strength;
 		chip->ecc.algo = NAND_ECC_ALGO_BCH;
 		chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
+		chip->ecc.read_subpage = micron_nand_read_subpage_on_die_ecc;
 		chip->ecc.write_page = micron_nand_write_page_on_die_ecc;
+		chip->ecc.write_subpage = micron_nand_write_subpage_on_die_ecc;
 
 		if (ondie == MICRON_ON_DIE_MANDATORY) {
 			chip->ecc.read_page_raw = nand_read_page_raw_notsupp;

drivers/mtd/nand/raw/pl35x-nand-controller.c

@@ -144,6 +144,14 @@ struct pl35x_nandc {
 	u8 *ecc_buf;
 };
 
+static bool enable_subpage_read = 1;
+module_param(enable_subpage_read, bool, 0444);
+MODULE_PARM_DESC(enable_subpage_read, "Load-time parameter to toggle subpage reads on supported nand chips. Enabled by default.");
+
+static bool enable_subpage_write = 1;
+module_param(enable_subpage_write, bool, 0444);
+MODULE_PARM_DESC(enable_subpage_write, "Load-time parameter to toggle subpage writes on supported nand chips. Enabled by default.");
+
 static inline struct pl35x_nandc *to_pl35x_nandc(struct nand_controller *ctrl)
 {
 	return container_of(ctrl, struct pl35x_nandc, controller);
@@ -499,14 +507,6 @@ static int pl35x_nand_recover_data_hwecc(struct pl35x_nandc *nfc,
 	return max_bitflips;
 }
 
-static int pl35x_nand_write_subpage_raw(struct nand_chip *chip,
-					uint32_t offset, uint32_t data_len,
-					const uint8_t *data_buf,
-					int oob_required, int page)
-{
-	return nand_monolithic_write_page_raw(chip, data_buf, oob_required, page);
-}
-
 static int pl35x_nand_write_page_hwecc(struct nand_chip *chip,
 				       const u8 *buf, int oob_required,
 				       int page)
@@ -667,12 +667,6 @@ static int pl35x_nand_read_page_hwecc(struct nand_chip *chip,
 	return ret;
 }
 
-static int pl35x_nand_read_subpage_raw(struct nand_chip *chip, uint32_t data_offs,
-				       uint32_t readlen, uint8_t *bufpoi, int page)
-{
-	return nand_read_page_op(chip, page, data_offs, bufpoi + data_offs, readlen);
-}
-
 static int pl35x_nand_exec_op(struct nand_chip *chip,
 			      const struct nand_subop *subop)
 {
@@ -991,27 +985,19 @@ static int pl35x_nand_init_hw_ecc_controller(struct pl35x_nandc *nfc,
 	return ret;
 }
 
-static void pl35x_nand_init_ondie_ecc(struct pl35x_nandc *nfc,
-				      struct nand_chip *chip)
+static void pl35x_nand_setup_ondie_ecc(struct nand_chip *chip)
 {
-	struct mtd_info *mtd = nand_to_mtd(chip);
-
-	/* Bypass the controller ECC block */
-	pl35x_smc_set_ecc_mode(nfc, chip, PL35X_SMC_ECC_CFG_MODE_BYPASS);
-
-	chip->ecc.strength = 1;
-	chip->ecc.bytes = 0;
-	chip->ecc.read_page = nand_monolithic_read_page_raw;
-	chip->ecc.read_page_raw = nand_monolithic_read_page_raw;
-	chip->ecc.read_subpage = pl35x_nand_read_subpage_raw;
-	chip->ecc.write_page = nand_monolithic_write_page_raw;
-	chip->ecc.write_page_raw = nand_monolithic_write_page_raw;
-	chip->ecc.write_subpage = pl35x_nand_write_subpage_raw;
-	chip->ecc.size = mtd->writesize;
+	/* NAND with on-die ECC supports subpage reads */
+	if (enable_subpage_read)
+		chip->options |= NAND_SUBPAGE_READ;
+	else
+		chip->options &= ~(NAND_SUBPAGE_READ);
 
-	/* NAND with on-die ECC supports subpage reads and writes */
-	chip->options |= NAND_SUBPAGE_READ;
-	chip->options &= ~(NAND_NO_SUBPAGE_WRITE);
+	/* NAND with on-die ECC may support subpage writes */
+	if (enable_subpage_write)
+		chip->options &= ~(NAND_NO_SUBPAGE_WRITE);
+	else
+		chip->options |= NAND_NO_SUBPAGE_WRITE;
 }
 
 static int pl35x_nand_attach_chip(struct nand_chip *chip)
@@ -1048,7 +1034,7 @@ static int pl35x_nand_attach_chip(struct nand_chip *chip)
 
 	switch (chip->ecc.engine_type) {
 	case NAND_ECC_ENGINE_TYPE_ON_DIE:
-		pl35x_nand_init_ondie_ecc(nfc, chip);
+		pl35x_nand_setup_ondie_ecc(chip);
 		/* Keep these legacy BBT descriptors for ON_DIE situations */
 		chip->bbt_td = &bbt_main_descr;
 		chip->bbt_md = &bbt_mirror_descr;