[PATCH v3 0/3] mtd: nand: mxc_nand: Convert to exec_op

[PATCH v3 0/3] mtd: nand: mxc_nand: Convert to exec_op

[Sascha Hauer]

This series converts the mxc_nand driver over to exec_op which gets
us rid of a bunch of legacy code. The motivation for this series is
a board that has a NAND chip connected that needs 4bit ECC whereas the
i.MX27 hardware only supports 1Bit Hamming ECC. With this series the
driver now supports software BCH ECC.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
Changes in v3:
- use monolithic page read/write helpers
- drop exec_op tracing debug functions
- use nand_op_parser_exec_op()
- move copy_spare() out of exec_op()
- fix comment about NFC handling R/B internally
- drop host->column. With using nand_op_parser_exec_op() we can forbid the core
  to issue multiple reads after a command
- Link to v2: https://lore.kernel.org/r/20240508-mtd-nand-mxc-nand-exec-op-v2-0-6b7366b7831f@pengutronix.de

Changes in v2:
- Enable hw ecc only when needed and leave it disabled otherwise
- Use untangled data/oob layout for software BCH ECC
- Link to v1: https://lore.kernel.org/r/20240417-mtd-nand-mxc-nand-exec-op-v1-0-d12564fe54e9@pengutronix.de

---
Sascha Hauer (3):
      mtd: nand: mxc_nand: separate page read from ecc calc
      mtd: nand: mxc_nand: implement exec_op
      mtd: nand: mxc_nand: support software ECC

 drivers/mtd/nand/raw/mxc_nand.c | 667 +++++++++++++++++++---------------------
 1 file changed, 314 insertions(+), 353 deletions(-)
---
base-commit: a38297e3fb012ddfa7ce0321a7e5a8daeb1872b6
change-id: 20240417-mtd-nand-mxc-nand-exec-op-38b3b80c4377

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH v3 1/3] mtd: nand: mxc_nand: separate page read from ecc calc

[Sascha Hauer]

Our read_page hook currently reads out a page and also counts and
returns the number of bitflips. In upcoming exec_op conversion we'll
need to read the page data in exec_op, but the bitflip information
will be needed in mxc_nand_read_page(). To ease exec_op conversion
separate the page read out from the bitflip evaluation.

For the v2/v3 controllers we can leave the bitflip information in the
status register for later evaluation. For the v1 controller this is
not possible, because the status register is overwritten with each
subpage read. We therefore store the bitflip information in the private
data.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/mtd/nand/raw/mxc_nand.c | 140 ++++++++++++++++++++++++----------------
 1 file changed, 86 insertions(+), 54 deletions(-)

diff --git a/drivers/mtd/nand/raw/mxc_nand.c b/drivers/mtd/nand/raw/mxc_nand.c
index 003008355b3c2..3fe0b471f4a2d 100644
--- a/drivers/mtd/nand/raw/mxc_nand.c
+++ b/drivers/mtd/nand/raw/mxc_nand.c
@@ -20,6 +20,7 @@
 #include <linux/irq.h>
 #include <linux/completion.h>
 #include <linux/of.h>
+#include <linux/bitfield.h>
 
 #define DRIVER_NAME "mxc_nand"
 
@@ -47,6 +48,8 @@
 #define NFC_V1_V2_CONFIG1		(host->regs + 0x1a)
 #define NFC_V1_V2_CONFIG2		(host->regs + 0x1c)
 
+#define NFC_V1_V2_ECC_STATUS_RESULT_ERM GENMASK(3, 2)
+
 #define NFC_V2_CONFIG1_ECC_MODE_4	(1 << 0)
 #define NFC_V1_V2_CONFIG1_SP_EN		(1 << 2)
 #define NFC_V1_V2_CONFIG1_ECC_EN	(1 << 3)
@@ -132,7 +135,7 @@ struct mxc_nand_devtype_data {
 	uint16_t (*get_dev_status)(struct mxc_nand_host *);
 	int (*check_int)(struct mxc_nand_host *);
 	void (*irq_control)(struct mxc_nand_host *, int);
-	u32 (*get_ecc_status)(struct mxc_nand_host *);
+	u32 (*get_ecc_status)(struct nand_chip *);
 	const struct mtd_ooblayout_ops *ooblayout;
 	void (*select_chip)(struct nand_chip *chip, int cs);
 	int (*setup_interface)(struct nand_chip *chip, int csline,
@@ -175,6 +178,7 @@ struct mxc_nand_host {
 	int			eccsize;
 	int			used_oobsize;
 	int			active_cs;
+	unsigned int		ecc_stats_v1;
 
 	struct completion	op_completion;
 
@@ -406,19 +410,81 @@ static void irq_control(struct mxc_nand_host *host, int activate)
 	}
 }
 
-static u32 get_ecc_status_v1(struct mxc_nand_host *host)
+static u32 get_ecc_status_v1(struct nand_chip *chip)
 {
-	return readw(NFC_V1_V2_ECC_STATUS_RESULT);
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
+	unsigned int ecc_stats, max_bitflips = 0;
+	int no_subpages, i;
+
+	no_subpages = mtd->writesize >> 9;
+
+	ecc_stats = host->ecc_stats_v1;
+
+	for (i = 0; i < no_subpages; i++) {
+		switch (ecc_stats & 0x3) {
+		case 0:
+		default:
+			break;
+		case 1:
+			mtd->ecc_stats.corrected++;
+			max_bitflips = 1;
+			break;
+		case 2:
+			mtd->ecc_stats.failed++;
+			break;
+		}
+
+		ecc_stats >>= 2;
+	}
+
+	return max_bitflips;
 }
 
-static u32 get_ecc_status_v2(struct mxc_nand_host *host)
+static u32 get_ecc_status_v2_v3(struct nand_chip *chip, unsigned int ecc_stat)
 {
-	return readl(NFC_V1_V2_ECC_STATUS_RESULT);
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
+	u8 ecc_bit_mask, err_limit;
+	unsigned int max_bitflips = 0;
+	int no_subpages, err;
+
+	ecc_bit_mask = (host->eccsize == 4) ? 0x7 : 0xf;
+	err_limit = (host->eccsize == 4) ? 0x4 : 0x8;
+
+	no_subpages = mtd->writesize >> 9;
+
+	do {
+		err = ecc_stat & ecc_bit_mask;
+		if (err > err_limit) {
+			mtd->ecc_stats.failed++;
+		} else {
+			mtd->ecc_stats.corrected += err;
+			max_bitflips = max_t(unsigned int, max_bitflips, err);
+		}
+
+		ecc_stat >>= 4;
+	} while (--no_subpages);
+
+	return max_bitflips;
 }
 
-static u32 get_ecc_status_v3(struct mxc_nand_host *host)
+static u32 get_ecc_status_v2(struct nand_chip *chip)
 {
-	return readl(NFC_V3_ECC_STATUS_RESULT);
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
+
+	u32 ecc_stat = readl(NFC_V1_V2_ECC_STATUS_RESULT);
+
+	return get_ecc_status_v2_v3(chip, ecc_stat);
+}
+
+static u32 get_ecc_status_v3(struct nand_chip *chip)
+{
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
+
+	u32 ecc_stat = readl(NFC_V3_ECC_STATUS_RESULT);
+
+	return get_ecc_status_v2_v3(chip, ecc_stat);
 }
 
 static irqreturn_t mxc_nfc_irq(int irq, void *dev_id)
@@ -712,9 +778,9 @@ static int mxc_nand_read_page_v1(struct nand_chip *chip, void *buf, void *oob,
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	struct mxc_nand_host *host = nand_get_controller_data(chip);
-	unsigned int bitflips_corrected = 0;
 	int no_subpages;
 	int i;
+	unsigned int ecc_stats = 0;
 
 	host->devtype_data->enable_hwecc(chip, ecc);
 
@@ -727,8 +793,6 @@ static int mxc_nand_read_page_v1(struct nand_chip *chip, void *buf, void *oob,
 	no_subpages = mtd->writesize >> 9;
 
 	for (i = 0; i < no_subpages; i++) {
-		uint16_t ecc_stats;
-
 		/* NANDFC buffer 0 is used for page read/write */
 		writew((host->active_cs << 4) | i, NFC_V1_V2_BUF_ADDR);
 
@@ -737,32 +801,18 @@ static int mxc_nand_read_page_v1(struct nand_chip *chip, void *buf, void *oob,
 		/* Wait for operation to complete */
 		wait_op_done(host, true);
 
-		ecc_stats = get_ecc_status_v1(host);
-
-		ecc_stats >>= 2;
-
-		if (buf && ecc) {
-			switch (ecc_stats & 0x3) {
-			case 0:
-			default:
-				break;
-			case 1:
-				mtd->ecc_stats.corrected++;
-				bitflips_corrected = 1;
-				break;
-			case 2:
-				mtd->ecc_stats.failed++;
-				break;
-			}
-		}
+		ecc_stats |= FIELD_GET(NFC_V1_V2_ECC_STATUS_RESULT_ERM,
+				       readw(NFC_V1_V2_ECC_STATUS_RESULT)) << i * 2;
 	}
 
+	host->ecc_stats_v1 = ecc_stats;
+
 	if (buf)
 		memcpy32_fromio(buf, host->main_area0, mtd->writesize);
 	if (oob)
 		copy_spare(mtd, true, oob);
 
-	return bitflips_corrected;
+	return 0;
 }
 
 static int mxc_nand_read_page_v2_v3(struct nand_chip *chip, void *buf,
@@ -770,10 +820,6 @@ static int mxc_nand_read_page_v2_v3(struct nand_chip *chip, void *buf,
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	struct mxc_nand_host *host = nand_get_controller_data(chip);
-	unsigned int max_bitflips = 0;
-	u32 ecc_stat, err;
-	int no_subpages;
-	u8 ecc_bit_mask, err_limit;
 
 	host->devtype_data->enable_hwecc(chip, ecc);
 
@@ -791,26 +837,7 @@ static int mxc_nand_read_page_v2_v3(struct nand_chip *chip, void *buf,
 	if (oob)
 		copy_spare(mtd, true, oob);
 
-	ecc_bit_mask = (host->eccsize == 4) ? 0x7 : 0xf;
-	err_limit = (host->eccsize == 4) ? 0x4 : 0x8;
-
-	no_subpages = mtd->writesize >> 9;
-
-	ecc_stat = host->devtype_data->get_ecc_status(host);
-
-	do {
-		err = ecc_stat & ecc_bit_mask;
-		if (err > err_limit) {
-			mtd->ecc_stats.failed++;
-		} else {
-			mtd->ecc_stats.corrected += err;
-			max_bitflips = max_t(unsigned int, max_bitflips, err);
-		}
-
-		ecc_stat >>= 4;
-	} while (--no_subpages);
-
-	return max_bitflips;
+	return 0;
 }
 
 static int mxc_nand_read_page(struct nand_chip *chip, uint8_t *buf,
@@ -818,13 +845,18 @@ static int mxc_nand_read_page(struct nand_chip *chip, uint8_t *buf,
 {
 	struct mxc_nand_host *host = nand_get_controller_data(chip);
 	void *oob_buf;
+	int ret;
 
 	if (oob_required)
 		oob_buf = chip->oob_poi;
 	else
 		oob_buf = NULL;
 
-	return host->devtype_data->read_page(chip, buf, oob_buf, 1, page);
+	ret = host->devtype_data->read_page(chip, buf, oob_buf, 1, page);
+	if (ret)
+		return ret;
+
+	return host->devtype_data->get_ecc_status(chip);
 }
 
 static int mxc_nand_read_page_raw(struct nand_chip *chip, uint8_t *buf,

-- 
2.39.2


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH v3 2/3] mtd: nand: mxc_nand: implement exec_op

[Sascha Hauer]

This converts the driver to the more modern exec_op which gets us rid
of a bunch of legacy code. Tested on i.MX27 and i.MX25.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/mtd/nand/raw/mxc_nand.c | 468 ++++++++++++++--------------------------
 1 file changed, 167 insertions(+), 301 deletions(-)

diff --git a/drivers/mtd/nand/raw/mxc_nand.c b/drivers/mtd/nand/raw/mxc_nand.c
index 3fe0b471f4a2d..6f8b8f4b118ec 100644
--- a/drivers/mtd/nand/raw/mxc_nand.c
+++ b/drivers/mtd/nand/raw/mxc_nand.c
@@ -126,8 +126,7 @@ struct mxc_nand_host;
 
 struct mxc_nand_devtype_data {
 	void (*preset)(struct mtd_info *);
-	int (*read_page)(struct nand_chip *chip, void *buf, void *oob, bool ecc,
-			 int page);
+	int (*read_page)(struct nand_chip *chip);
 	void (*send_cmd)(struct mxc_nand_host *, uint16_t, int);
 	void (*send_addr)(struct mxc_nand_host *, uint16_t, int);
 	void (*send_page)(struct mtd_info *, unsigned int);
@@ -182,8 +181,7 @@ struct mxc_nand_host {
 
 	struct completion	op_completion;
 
-	uint8_t			*data_buf;
-	unsigned int		buf_start;
+	void			*data_buf;
 
 	const struct mxc_nand_devtype_data *devtype_data;
 };
@@ -285,63 +283,6 @@ static void copy_spare(struct mtd_info *mtd, bool bfrom, void *buf)
 	}
 }
 
-/*
- * MXC NANDFC can only perform full page+spare or spare-only read/write.  When
- * the upper layers perform a read/write buf operation, the saved column address
- * is used to index into the full page. So usually this function is called with
- * column == 0 (unless no column cycle is needed indicated by column == -1)
- */
-static void mxc_do_addr_cycle(struct mtd_info *mtd, int column, int page_addr)
-{
-	struct nand_chip *nand_chip = mtd_to_nand(mtd);
-	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
-
-	/* Write out column address, if necessary */
-	if (column != -1) {
-		host->devtype_data->send_addr(host, column & 0xff,
-					      page_addr == -1);
-		if (mtd->writesize > 512)
-			/* another col addr cycle for 2k page */
-			host->devtype_data->send_addr(host,
-						      (column >> 8) & 0xff,
-						      false);
-	}
-
-	/* Write out page address, if necessary */
-	if (page_addr != -1) {
-		/* paddr_0 - p_addr_7 */
-		host->devtype_data->send_addr(host, (page_addr & 0xff), false);
-
-		if (mtd->writesize > 512) {
-			if (mtd->size >= 0x10000000) {
-				/* paddr_8 - paddr_15 */
-				host->devtype_data->send_addr(host,
-						(page_addr >> 8) & 0xff,
-						false);
-				host->devtype_data->send_addr(host,
-						(page_addr >> 16) & 0xff,
-						true);
-			} else
-				/* paddr_8 - paddr_15 */
-				host->devtype_data->send_addr(host,
-						(page_addr >> 8) & 0xff, true);
-		} else {
-			if (nand_chip->options & NAND_ROW_ADDR_3) {
-				/* paddr_8 - paddr_15 */
-				host->devtype_data->send_addr(host,
-						(page_addr >> 8) & 0xff,
-						false);
-				host->devtype_data->send_addr(host,
-						(page_addr >> 16) & 0xff,
-						true);
-			} else
-				/* paddr_8 - paddr_15 */
-				host->devtype_data->send_addr(host,
-						(page_addr >> 8) & 0xff, true);
-		}
-	}
-}
-
 static int check_int_v3(struct mxc_nand_host *host)
 {
 	uint32_t tmp;
@@ -763,18 +704,7 @@ static void mxc_nand_enable_hwecc_v3(struct nand_chip *chip, bool enable)
 	writel(config2, NFC_V3_CONFIG2);
 }
 
-/* This functions is used by upper layer to checks if device is ready */
-static int mxc_nand_dev_ready(struct nand_chip *chip)
-{
-	/*
-	 * NFC handles R/B internally. Therefore, this function
-	 * always returns status as ready.
-	 */
-	return 1;
-}
-
-static int mxc_nand_read_page_v1(struct nand_chip *chip, void *buf, void *oob,
-				 bool ecc, int page)
+static int mxc_nand_read_page_v1(struct nand_chip *chip)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	struct mxc_nand_host *host = nand_get_controller_data(chip);
@@ -782,15 +712,11 @@ static int mxc_nand_read_page_v1(struct nand_chip *chip, void *buf, void *oob,
 	int i;
 	unsigned int ecc_stats = 0;
 
-	host->devtype_data->enable_hwecc(chip, ecc);
-
-	host->devtype_data->send_cmd(host, NAND_CMD_READ0, false);
-	mxc_do_addr_cycle(mtd, 0, page);
-
-	if (mtd->writesize > 512)
-		host->devtype_data->send_cmd(host, NAND_CMD_READSTART, true);
-
-	no_subpages = mtd->writesize >> 9;
+	if (mtd->writesize)
+		no_subpages = mtd->writesize >> 9;
+	else
+		/* READ PARAMETER PAGE is called when mtd->writesize is not yet set */
+		no_subpages = 1;
 
 	for (i = 0; i < no_subpages; i++) {
 		/* NANDFC buffer 0 is used for page read/write */
@@ -807,181 +733,111 @@ static int mxc_nand_read_page_v1(struct nand_chip *chip, void *buf, void *oob,
 
 	host->ecc_stats_v1 = ecc_stats;
 
-	if (buf)
-		memcpy32_fromio(buf, host->main_area0, mtd->writesize);
-	if (oob)
-		copy_spare(mtd, true, oob);
-
 	return 0;
 }
 
-static int mxc_nand_read_page_v2_v3(struct nand_chip *chip, void *buf,
-				    void *oob, bool ecc, int page)
+static int mxc_nand_read_page_v2_v3(struct nand_chip *chip)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	struct mxc_nand_host *host = nand_get_controller_data(chip);
 
-	host->devtype_data->enable_hwecc(chip, ecc);
-
-	host->devtype_data->send_cmd(host, NAND_CMD_READ0, false);
-	mxc_do_addr_cycle(mtd, 0, page);
-
-	if (mtd->writesize > 512)
-		host->devtype_data->send_cmd(host,
-				NAND_CMD_READSTART, true);
-
 	host->devtype_data->send_page(mtd, NFC_OUTPUT);
 
-	if (buf)
-		memcpy32_fromio(buf, host->main_area0, mtd->writesize);
-	if (oob)
-		copy_spare(mtd, true, oob);
-
 	return 0;
 }
 
 static int mxc_nand_read_page(struct nand_chip *chip, uint8_t *buf,
 			      int oob_required, int page)
 {
+	struct mtd_info *mtd = nand_to_mtd(chip);
 	struct mxc_nand_host *host = nand_get_controller_data(chip);
-	void *oob_buf;
 	int ret;
 
-	if (oob_required)
-		oob_buf = chip->oob_poi;
-	else
-		oob_buf = NULL;
+	host->devtype_data->enable_hwecc(chip, true);
+
+	ret = nand_read_page_op(chip, page, 0, buf, mtd->writesize);
+
+	host->devtype_data->enable_hwecc(chip, false);
 
-	ret = host->devtype_data->read_page(chip, buf, oob_buf, 1, page);
 	if (ret)
 		return ret;
 
+	if (oob_required)
+		copy_spare(mtd, true, chip->oob_poi);
+
 	return host->devtype_data->get_ecc_status(chip);
 }
 
 static int mxc_nand_read_page_raw(struct nand_chip *chip, uint8_t *buf,
 				  int oob_required, int page)
 {
-	struct mxc_nand_host *host = nand_get_controller_data(chip);
-	void *oob_buf;
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	int ret;
+
+	ret = nand_read_page_op(chip, page, 0, buf, mtd->writesize);
+	if (ret)
+		return ret;
 
 	if (oob_required)
-		oob_buf = chip->oob_poi;
-	else
-		oob_buf = NULL;
+		copy_spare(mtd, true, chip->oob_poi);
 
-	return host->devtype_data->read_page(chip, buf, oob_buf, 0, page);
+	return 0;
 }
 
 static int mxc_nand_read_oob(struct nand_chip *chip, int page)
-{
-	struct mxc_nand_host *host = nand_get_controller_data(chip);
-
-	return host->devtype_data->read_page(chip, NULL, chip->oob_poi, 0,
-					     page);
-}
-
-static int mxc_nand_write_page(struct nand_chip *chip, const uint8_t *buf,
-			       bool ecc, int page)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	struct mxc_nand_host *host = nand_get_controller_data(chip);
+	int ret;
 
-	host->devtype_data->enable_hwecc(chip, ecc);
-
-	host->devtype_data->send_cmd(host, NAND_CMD_SEQIN, false);
-	mxc_do_addr_cycle(mtd, 0, page);
-
-	memcpy32_toio(host->main_area0, buf, mtd->writesize);
-	copy_spare(mtd, false, chip->oob_poi);
+	ret = nand_read_page_op(chip, page, 0, host->data_buf, mtd->writesize);
+	if (ret)
+		return ret;
 
-	host->devtype_data->send_page(mtd, NFC_INPUT);
-	host->devtype_data->send_cmd(host, NAND_CMD_PAGEPROG, true);
-	mxc_do_addr_cycle(mtd, 0, page);
+	copy_spare(mtd, true, chip->oob_poi);
 
 	return 0;
 }
 
 static int mxc_nand_write_page_ecc(struct nand_chip *chip, const uint8_t *buf,
 				   int oob_required, int page)
-{
-	return mxc_nand_write_page(chip, buf, true, page);
-}
-
-static int mxc_nand_write_page_raw(struct nand_chip *chip, const uint8_t *buf,
-				   int oob_required, int page)
-{
-	return mxc_nand_write_page(chip, buf, false, page);
-}
-
-static int mxc_nand_write_oob(struct nand_chip *chip, int page)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	struct mxc_nand_host *host = nand_get_controller_data(chip);
+	int ret;
 
-	memset(host->data_buf, 0xff, mtd->writesize);
-
-	return mxc_nand_write_page(chip, host->data_buf, false, page);
-}
+	if (oob_required)
+		copy_spare(mtd, false, chip->oob_poi);
 
-static u_char mxc_nand_read_byte(struct nand_chip *nand_chip)
-{
-	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
-	uint8_t ret;
+	host->devtype_data->enable_hwecc(chip, true);
 
-	/* Check for status request */
-	if (host->status_request)
-		return host->devtype_data->get_dev_status(host) & 0xFF;
+	ret = nand_prog_page_op(chip, page, 0, buf, mtd->writesize);
 
-	if (nand_chip->options & NAND_BUSWIDTH_16) {
-		/* only take the lower byte of each word */
-		ret = *(uint16_t *)(host->data_buf + host->buf_start);
+	host->devtype_data->enable_hwecc(chip, false);
 
-		host->buf_start += 2;
-	} else {
-		ret = *(uint8_t *)(host->data_buf + host->buf_start);
-		host->buf_start++;
-	}
-
-	dev_dbg(host->dev, "%s: ret=0x%hhx (start=%u)\n", __func__, ret, host->buf_start);
 	return ret;
 }
 
-/* Write data of length len to buffer buf. The data to be
- * written on NAND Flash is first copied to RAMbuffer. After the Data Input
- * Operation by the NFC, the data is written to NAND Flash */
-static void mxc_nand_write_buf(struct nand_chip *nand_chip, const u_char *buf,
-			       int len)
+static int mxc_nand_write_page_raw(struct nand_chip *chip, const uint8_t *buf,
+				   int oob_required, int page)
 {
-	struct mtd_info *mtd = nand_to_mtd(nand_chip);
-	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
-	u16 col = host->buf_start;
-	int n = mtd->oobsize + mtd->writesize - col;
-
-	n = min(n, len);
+	struct mtd_info *mtd = nand_to_mtd(chip);
 
-	memcpy(host->data_buf + col, buf, n);
+	if (oob_required)
+		copy_spare(mtd, false, chip->oob_poi);
 
-	host->buf_start += n;
+	return nand_prog_page_op(chip, page, 0, buf, mtd->writesize);
 }
 
-/* Read the data buffer from the NAND Flash. To read the data from NAND
- * Flash first the data output cycle is initiated by the NFC, which copies
- * the data to RAMbuffer. This data of length len is then copied to buffer buf.
- */
-static void mxc_nand_read_buf(struct nand_chip *nand_chip, u_char *buf,
-			      int len)
+static int mxc_nand_write_oob(struct nand_chip *chip, int page)
 {
-	struct mtd_info *mtd = nand_to_mtd(nand_chip);
-	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
-	u16 col = host->buf_start;
-	int n = mtd->oobsize + mtd->writesize - col;
-
-	n = min(n, len);
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
 
-	memcpy(buf, host->data_buf + col, n);
+	memset(host->data_buf, 0xff, mtd->writesize);
+	copy_spare(mtd, false, chip->oob_poi);
 
-	host->buf_start += n;
+	return nand_prog_page_op(chip, page, 0, host->data_buf, mtd->writesize);
 }
 
 /* This function is used by upper layer for select and
@@ -1360,107 +1216,6 @@ static void preset_v3(struct mtd_info *mtd)
 	writel(0, NFC_V3_DELAY_LINE);
 }
 
-/* Used by the upper layer to write command to NAND Flash for
- * different operations to be carried out on NAND Flash */
-static void mxc_nand_command(struct nand_chip *nand_chip, unsigned command,
-			     int column, int page_addr)
-{
-	struct mtd_info *mtd = nand_to_mtd(nand_chip);
-	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
-
-	dev_dbg(host->dev, "mxc_nand_command (cmd = 0x%x, col = 0x%x, page = 0x%x)\n",
-	      command, column, page_addr);
-
-	/* Reset command state information */
-	host->status_request = false;
-
-	/* Command pre-processing step */
-	switch (command) {
-	case NAND_CMD_RESET:
-		host->devtype_data->preset(mtd);
-		host->devtype_data->send_cmd(host, command, false);
-		break;
-
-	case NAND_CMD_STATUS:
-		host->buf_start = 0;
-		host->status_request = true;
-
-		host->devtype_data->send_cmd(host, command, true);
-		WARN_ONCE(column != -1 || page_addr != -1,
-			  "Unexpected column/row value (cmd=%u, col=%d, row=%d)\n",
-			  command, column, page_addr);
-		mxc_do_addr_cycle(mtd, column, page_addr);
-		break;
-
-	case NAND_CMD_READID:
-		host->devtype_data->send_cmd(host, command, true);
-		mxc_do_addr_cycle(mtd, column, page_addr);
-		host->devtype_data->send_read_id(host);
-		host->buf_start = 0;
-		break;
-
-	case NAND_CMD_ERASE1:
-	case NAND_CMD_ERASE2:
-		host->devtype_data->send_cmd(host, command, false);
-		WARN_ONCE(column != -1,
-			  "Unexpected column value (cmd=%u, col=%d)\n",
-			  command, column);
-		mxc_do_addr_cycle(mtd, column, page_addr);
-
-		break;
-	case NAND_CMD_PARAM:
-		host->devtype_data->send_cmd(host, command, false);
-		mxc_do_addr_cycle(mtd, column, page_addr);
-		host->devtype_data->send_page(mtd, NFC_OUTPUT);
-		memcpy32_fromio(host->data_buf, host->main_area0, 512);
-		host->buf_start = 0;
-		break;
-	default:
-		WARN_ONCE(1, "Unimplemented command (cmd=%u)\n",
-			  command);
-		break;
-	}
-}
-
-static int mxc_nand_set_features(struct nand_chip *chip, int addr,
-				 u8 *subfeature_param)
-{
-	struct mtd_info *mtd = nand_to_mtd(chip);
-	struct mxc_nand_host *host = nand_get_controller_data(chip);
-	int i;
-
-	host->buf_start = 0;
-
-	for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i)
-		chip->legacy.write_byte(chip, subfeature_param[i]);
-
-	memcpy32_toio(host->main_area0, host->data_buf, mtd->writesize);
-	host->devtype_data->send_cmd(host, NAND_CMD_SET_FEATURES, false);
-	mxc_do_addr_cycle(mtd, addr, -1);
-	host->devtype_data->send_page(mtd, NFC_INPUT);
-
-	return 0;
-}
-
-static int mxc_nand_get_features(struct nand_chip *chip, int addr,
-				 u8 *subfeature_param)
-{
-	struct mtd_info *mtd = nand_to_mtd(chip);
-	struct mxc_nand_host *host = nand_get_controller_data(chip);
-	int i;
-
-	host->devtype_data->send_cmd(host, NAND_CMD_GET_FEATURES, false);
-	mxc_do_addr_cycle(mtd, addr, -1);
-	host->devtype_data->send_page(mtd, NFC_OUTPUT);
-	memcpy32_fromio(host->data_buf, host->main_area0, 512);
-	host->buf_start = 0;
-
-	for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i)
-		*subfeature_param++ = chip->legacy.read_byte(chip);
-
-	return 0;
-}
-
 /*
  * The generic flash bbt descriptors overlap with our ecc
  * hardware, so define some i.MX specific ones.
@@ -1717,9 +1472,127 @@ static int mxcnd_setup_interface(struct nand_chip *chip, int chipnr,
 	return host->devtype_data->setup_interface(chip, chipnr, conf);
 }
 
+static int mxcnd_do_exec_op(struct nand_chip *chip,
+			    const struct nand_subop *op)
+{
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	int i, j, buf_len;
+	void *buf_read = NULL;
+	const void *buf_write = NULL;
+	const struct nand_op_instr *instr;
+	bool readid = false;
+	bool statusreq = false;
+
+	for (i = 0; i < op->ninstrs; i++) {
+		instr = &op->instrs[i];
+
+		switch (instr->type) {
+		case NAND_OP_WAITRDY_INSTR:
+			/* NFC handles R/B internally, nothing to do here */
+			break;
+		case NAND_OP_CMD_INSTR:
+			host->devtype_data->send_cmd(host, instr->ctx.cmd.opcode, true);
+
+			if (instr->ctx.cmd.opcode == NAND_CMD_READID)
+				readid = true;
+			if (instr->ctx.cmd.opcode == NAND_CMD_STATUS)
+				statusreq = true;
+
+			break;
+		case NAND_OP_ADDR_INSTR:
+			for (j = 0; j < instr->ctx.addr.naddrs; j++) {
+				bool islast = j == instr->ctx.addr.naddrs - 1;
+				host->devtype_data->send_addr(host, instr->ctx.addr.addrs[j], islast);
+			}
+			break;
+		case NAND_OP_DATA_OUT_INSTR:
+			buf_write = instr->ctx.data.buf.out;
+			buf_len = instr->ctx.data.len;
+
+			memcpy32_toio(host->main_area0, buf_write, buf_len);
+
+			host->devtype_data->send_page(mtd, NFC_INPUT);
+
+			break;
+		case NAND_OP_DATA_IN_INSTR:
+
+			buf_read = instr->ctx.data.buf.in;
+			buf_len = instr->ctx.data.len;
+
+			if (readid) {
+				host->devtype_data->send_read_id(host);
+				readid = false;
+
+				memcpy32_fromio(host->data_buf, host->main_area0, buf_len * 2);
+
+				if (chip->options & NAND_BUSWIDTH_16) {
+					u8 *bufr = buf_read;
+					u16 *bufw = host->data_buf;
+					for (j = 0; j < buf_len; j++)
+						bufr[j] = bufw[j];
+				} else {
+					memcpy(buf_read, host->data_buf, buf_len);
+				}
+				break;
+			}
+
+			if (statusreq) {
+				*(u8*)buf_read = host->devtype_data->get_dev_status(host);
+				statusreq = false;
+				break;
+			}
+
+			host->devtype_data->read_page(chip);
+
+			if (IS_ALIGNED(buf_len, 4)) {
+				memcpy32_fromio(buf_read, host->main_area0, buf_len);
+			} else {
+				memcpy32_fromio(host->data_buf, host->main_area0, mtd->writesize);
+				memcpy(buf_read, host->data_buf, buf_len);
+			}
+
+			break;
+		}
+	}
+
+	return 0;
+}
+
+#define MAX_DATA_SIZE	(4096 + 512)
+
+static const struct nand_op_parser mxcnd_op_parser = NAND_OP_PARSER(
+	NAND_OP_PARSER_PATTERN(mxcnd_do_exec_op,
+			       NAND_OP_PARSER_PAT_CMD_ELEM(false),
+			       NAND_OP_PARSER_PAT_ADDR_ELEM(true, 7),
+			       NAND_OP_PARSER_PAT_CMD_ELEM(true),
+			       NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
+			       NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, MAX_DATA_SIZE)),
+	NAND_OP_PARSER_PATTERN(mxcnd_do_exec_op,
+			       NAND_OP_PARSER_PAT_CMD_ELEM(false),
+			       NAND_OP_PARSER_PAT_ADDR_ELEM(false, 7),
+			       NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, MAX_DATA_SIZE),
+			       NAND_OP_PARSER_PAT_CMD_ELEM(false),
+			       NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
+	NAND_OP_PARSER_PATTERN(mxcnd_do_exec_op,
+			       NAND_OP_PARSER_PAT_CMD_ELEM(false),
+			       NAND_OP_PARSER_PAT_ADDR_ELEM(false, 7),
+			       NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, MAX_DATA_SIZE),
+			       NAND_OP_PARSER_PAT_CMD_ELEM(true),
+			       NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
+	);
+
+static int mxcnd_exec_op(struct nand_chip *chip,
+			 const struct nand_operation *op, bool check_only)
+{
+	return nand_op_parser_exec_op(chip, &mxcnd_op_parser,
+				      op, check_only);
+}
+
 static const struct nand_controller_ops mxcnd_controller_ops = {
 	.attach_chip = mxcnd_attach_chip,
 	.setup_interface = mxcnd_setup_interface,
+	.exec_op = mxcnd_exec_op,
 };
 
 static int mxcnd_probe(struct platform_device *pdev)
@@ -1752,13 +1625,6 @@ static int mxcnd_probe(struct platform_device *pdev)
 
 	nand_set_controller_data(this, host);
 	nand_set_flash_node(this, pdev->dev.of_node);
-	this->legacy.dev_ready = mxc_nand_dev_ready;
-	this->legacy.cmdfunc = mxc_nand_command;
-	this->legacy.read_byte = mxc_nand_read_byte;
-	this->legacy.write_buf = mxc_nand_write_buf;
-	this->legacy.read_buf = mxc_nand_read_buf;
-	this->legacy.set_features = mxc_nand_set_features;
-	this->legacy.get_features = mxc_nand_get_features;
 
 	host->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(host->clk))

-- 
2.39.2


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Re: [PATCH v3 2/3] mtd: nand: mxc_nand: implement exec_op

[Miquel Raynal]

Hi Sascha,

> +static const struct nand_op_parser mxcnd_op_parser = NAND_OP_PARSER(
> +	NAND_OP_PARSER_PATTERN(mxcnd_do_exec_op,
> +			       NAND_OP_PARSER_PAT_CMD_ELEM(false),
> +			       NAND_OP_PARSER_PAT_ADDR_ELEM(true, 7),
> +			       NAND_OP_PARSER_PAT_CMD_ELEM(true),
> +			       NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
> +			       NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, MAX_DATA_SIZE)),

CMD, ADDR, CMD, DATA is the RNDOUT pattern. So it is now working fine?
Or did you forget to adapt the patterns to your use case?


Thanks,
Miquèl

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Re: [PATCH v3 2/3] mtd: nand: mxc_nand: implement exec_op

[Sascha Hauer]

On Thu, May 16, 2024 at 10:32:14AM +0200, Miquel Raynal wrote:
> Hi Sascha,
> 
> > +static const struct nand_op_parser mxcnd_op_parser = NAND_OP_PARSER(
> > +	NAND_OP_PARSER_PATTERN(mxcnd_do_exec_op,
> > +			       NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > +			       NAND_OP_PARSER_PAT_ADDR_ELEM(true, 7),
> > +			       NAND_OP_PARSER_PAT_CMD_ELEM(true),
> > +			       NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
> > +			       NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, MAX_DATA_SIZE)),
> 
> CMD, ADDR, CMD, DATA is the RNDOUT pattern. So it is now working fine?

Yes, RNDOUT is working now.

> Or did you forget to adapt the patterns to your use case?

Although it looks like the patterns from the pl35x-nand-controller.c,
there is one slight difference. The 'false' in the NAND_OP_PARSER_PAT_CMD_ELEM
above has the effect that a plain NAND_OP_PARSER_PAT_DATA_IN_ELEM is
disallowed.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: [PATCH v3 2/3] mtd: nand: mxc_nand: implement exec_op

[Miquel Raynal]

Hi Sascha,

s.hauer@pengutronix.de wrote on Thu, 16 May 2024 12:25:43 +0200:

> On Thu, May 16, 2024 at 10:32:14AM +0200, Miquel Raynal wrote:
> > Hi Sascha,
> >   
> > > +static const struct nand_op_parser mxcnd_op_parser = NAND_OP_PARSER(
> > > +	NAND_OP_PARSER_PATTERN(mxcnd_do_exec_op,
> > > +			       NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > > +			       NAND_OP_PARSER_PAT_ADDR_ELEM(true, 7),
> > > +			       NAND_OP_PARSER_PAT_CMD_ELEM(true),
> > > +			       NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
> > > +			       NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, MAX_DATA_SIZE)),  
> > 
> > CMD, ADDR, CMD, DATA is the RNDOUT pattern. So it is now working fine?  
> 
> Yes, RNDOUT is working now.

Excellent!

> > Or did you forget to adapt the patterns to your use case?  
> 
> Although it looks like the patterns from the pl35x-nand-controller.c,
> there is one slight difference. The 'false' in the NAND_OP_PARSER_PAT_CMD_ELEM
> above has the effect that a plain NAND_OP_PARSER_PAT_DATA_IN_ELEM is
> disallowed.

I'm not sure I follow, the above pattern means: a single command cycle
is supported, no?

Miquèl

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Re: [PATCH v3 2/3] mtd: nand: mxc_nand: implement exec_op

[Sascha Hauer]

On Thu, May 16, 2024 at 12:44:05PM +0200, Miquel Raynal wrote:
> Hi Sascha,
> 
> s.hauer@pengutronix.de wrote on Thu, 16 May 2024 12:25:43 +0200:
> 
> > On Thu, May 16, 2024 at 10:32:14AM +0200, Miquel Raynal wrote:
> > > Hi Sascha,
> > >   
> > > > +static const struct nand_op_parser mxcnd_op_parser = NAND_OP_PARSER(
> > > > +	NAND_OP_PARSER_PATTERN(mxcnd_do_exec_op,
> > > > +			       NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > > > +			       NAND_OP_PARSER_PAT_ADDR_ELEM(true, 7),
> > > > +			       NAND_OP_PARSER_PAT_CMD_ELEM(true),
> > > > +			       NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
> > > > +			       NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, MAX_DATA_SIZE)),  
> > > 
> > > CMD, ADDR, CMD, DATA is the RNDOUT pattern. So it is now working fine?  
> > 
> > Yes, RNDOUT is working now.
> 
> Excellent!
> 
> > > Or did you forget to adapt the patterns to your use case?  
> > 
> > Although it looks like the patterns from the pl35x-nand-controller.c,
> > there is one slight difference. The 'false' in the NAND_OP_PARSER_PAT_CMD_ELEM
> > above has the effect that a plain NAND_OP_PARSER_PAT_DATA_IN_ELEM is
> > disallowed.
> 
> I'm not sure I follow, the above pattern means: a single command cycle
> is supported, no?

A single command cycle indeed is and shall be supported. The
pl35x-nand-controller.c I copied this from has
NAND_OP_PARSER_PAT_CMD_ELEM(true). With all elements being optional this
also allows a single NAND_OP_PARSER_PAT_DATA_IN_ELEM()
(supported_op.data_only_read becomes true). I can't support that, so I
made the CMD mandatory.

Sascha

> 
> Miquèl
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: [PATCH v3 2/3] mtd: nand: mxc_nand: implement exec_op

[Miquel Raynal]

Hi Sascha,

s.hauer@pengutronix.de wrote on Thu, 16 May 2024 13:36:42 +0200:

> On Thu, May 16, 2024 at 12:44:05PM +0200, Miquel Raynal wrote:
> > Hi Sascha,
> > 
> > s.hauer@pengutronix.de wrote on Thu, 16 May 2024 12:25:43 +0200:
> >   
> > > On Thu, May 16, 2024 at 10:32:14AM +0200, Miquel Raynal wrote:  
> > > > Hi Sascha,
> > > >     
> > > > > +static const struct nand_op_parser mxcnd_op_parser = NAND_OP_PARSER(
> > > > > +	NAND_OP_PARSER_PATTERN(mxcnd_do_exec_op,
> > > > > +			       NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > > > > +			       NAND_OP_PARSER_PAT_ADDR_ELEM(true, 7),
> > > > > +			       NAND_OP_PARSER_PAT_CMD_ELEM(true),
> > > > > +			       NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
> > > > > +			       NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, MAX_DATA_SIZE)),    
> > > > 
> > > > CMD, ADDR, CMD, DATA is the RNDOUT pattern. So it is now working fine?    
> > > 
> > > Yes, RNDOUT is working now.  
> > 
> > Excellent!
> >   
> > > > Or did you forget to adapt the patterns to your use case?    
> > > 
> > > Although it looks like the patterns from the pl35x-nand-controller.c,
> > > there is one slight difference. The 'false' in the NAND_OP_PARSER_PAT_CMD_ELEM
> > > above has the effect that a plain NAND_OP_PARSER_PAT_DATA_IN_ELEM is
> > > disallowed.  
> > 
> > I'm not sure I follow, the above pattern means: a single command cycle
> > is supported, no?  
> 
> A single command cycle indeed is and shall be supported. The
> pl35x-nand-controller.c I copied this from has
> NAND_OP_PARSER_PAT_CMD_ELEM(true). With all elements being optional this
> also allows a single NAND_OP_PARSER_PAT_DATA_IN_ELEM()
> (supported_op.data_only_read becomes true). I can't support that, so I
> made the CMD mandatory.

Alright, yeah. Ack.

Thanks,
Miquèl

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[PATCH v3 3/3] mtd: nand: mxc_nand: support software ECC

[Sascha Hauer]

With these changes the driver can be used with software BCH ECC which
is useful for NAND chips that require a stronger ECC than the i.MX
hardware supports.

The controller normally interleaves user data with OOB data when
accessing the NAND chip. With Software BCH ECC we write the data
to the NAND in a way that the raw data on the NAND chip matches the
way the NAND layer sees it. This way commands like NAND_CMD_RNDOUT
work as expected.

This was tested on i.MX27 but should work on the other SoCs supported
by this driver as well.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/mtd/nand/raw/mxc_nand.c | 73 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 68 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/raw/mxc_nand.c b/drivers/mtd/nand/raw/mxc_nand.c
index 6f8b8f4b118ec..ae4cff2584a2d 100644
--- a/drivers/mtd/nand/raw/mxc_nand.c
+++ b/drivers/mtd/nand/raw/mxc_nand.c
@@ -1404,10 +1404,10 @@ static int mxcnd_attach_chip(struct nand_chip *chip)
 	chip->ecc.bytes = host->devtype_data->eccbytes;
 	host->eccsize = host->devtype_data->eccsize;
 	chip->ecc.size = 512;
-	mtd_set_ooblayout(mtd, host->devtype_data->ooblayout);
 
 	switch (chip->ecc.engine_type) {
 	case NAND_ECC_ENGINE_TYPE_ON_HOST:
+		mtd_set_ooblayout(mtd, host->devtype_data->ooblayout);
 		chip->ecc.read_page = mxc_nand_read_page;
 		chip->ecc.read_page_raw = mxc_nand_read_page_raw;
 		chip->ecc.read_oob = mxc_nand_read_oob;
@@ -1417,6 +1417,8 @@ static int mxcnd_attach_chip(struct nand_chip *chip)
 		break;
 
 	case NAND_ECC_ENGINE_TYPE_SOFT:
+		chip->ecc.write_page_raw = nand_monolithic_write_page_raw;
+		chip->ecc.read_page_raw = nand_monolithic_read_page_raw;
 		break;
 
 	default:
@@ -1472,6 +1474,59 @@ static int mxcnd_setup_interface(struct nand_chip *chip, int chipnr,
 	return host->devtype_data->setup_interface(chip, chipnr, conf);
 }
 
+static void copy_page_to_sram(struct mtd_info *mtd, const void *buf, int buf_len)
+{
+	struct nand_chip *this = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(this);
+	unsigned int no_subpages = mtd->writesize / 512;
+	int oob_per_subpage, i;
+
+	oob_per_subpage = (mtd->oobsize / no_subpages) & ~1;
+
+	/*
+	 * During a page write the i.MX NAND controller will read 512b from
+	 * main_area0 SRAM, then oob_per_subpage bytes from spare0 SRAM, then
+	 * 512b from main_area1 SRAM and so on until the full page is written.
+	 * For software ECC we want to have a 1:1 mapping between the raw page
+	 * data on the NAND chip and the view of the NAND core. This is
+	 * necessary to make the NAND_CMD_RNDOUT read the data it expects.
+	 * To accomplish this we have to write the data in the order the controller
+	 * reads it. This is reversed in copy_page_from_sram() below.
+	 */
+	for (i = 0; i < no_subpages; i++) {
+		memcpy16_toio(host->main_area0 + i * 512, buf, 512);
+		buf += 512;
+
+		memcpy16_toio(host->spare0 + i * host->devtype_data->spare_len, buf,
+			      oob_per_subpage);
+		buf += oob_per_subpage;
+	}
+}
+
+static void copy_page_from_sram(struct mtd_info *mtd)
+{
+	struct nand_chip *this = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(this);
+	void *buf = host->data_buf;
+	unsigned int no_subpages = mtd->writesize / 512;
+	int oob_per_subpage, i;
+
+	/* mtd->writesize is not set during ident scanning */
+	if (!no_subpages)
+		no_subpages = 1;
+
+	oob_per_subpage = (mtd->oobsize / no_subpages) & ~1;
+
+	for (i = 0; i < no_subpages; i++) {
+		memcpy16_fromio(buf, host->main_area0 + i * 512, 512);
+		buf += 512;
+
+		memcpy16_fromio(buf, host->spare0 + i * host->devtype_data->spare_len,
+				oob_per_subpage);
+		buf += oob_per_subpage;
+	}
+}
+
 static int mxcnd_do_exec_op(struct nand_chip *chip,
 			    const struct nand_subop *op)
 {
@@ -1510,7 +1565,10 @@ static int mxcnd_do_exec_op(struct nand_chip *chip,
 			buf_write = instr->ctx.data.buf.out;
 			buf_len = instr->ctx.data.len;
 
-			memcpy32_toio(host->main_area0, buf_write, buf_len);
+			if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST)
+				memcpy32_toio(host->main_area0, buf_write, buf_len);
+			else
+				copy_page_to_sram(mtd, buf_write, buf_len);
 
 			host->devtype_data->send_page(mtd, NFC_INPUT);
 
@@ -1545,10 +1603,15 @@ static int mxcnd_do_exec_op(struct nand_chip *chip,
 
 			host->devtype_data->read_page(chip);
 
-			if (IS_ALIGNED(buf_len, 4)) {
-				memcpy32_fromio(buf_read, host->main_area0, buf_len);
+			if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST) {
+				if (IS_ALIGNED(buf_len, 4)) {
+					memcpy32_fromio(buf_read, host->main_area0, buf_len);
+				} else {
+					memcpy32_fromio(host->data_buf, host->main_area0, mtd->writesize);
+					memcpy(buf_read, host->data_buf, buf_len);
+				}
 			} else {
-				memcpy32_fromio(host->data_buf, host->main_area0, mtd->writesize);
+				copy_page_from_sram(mtd);
 				memcpy(buf_read, host->data_buf, buf_len);
 			}
 

-- 
2.39.2


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Re: [PATCH v3 3/3] mtd: nand: mxc_nand: support software ECC

[Sascha Hauer]

On Tue, May 14, 2024 at 04:25:19PM +0200, Sascha Hauer wrote:
> With these changes the driver can be used with software BCH ECC which
> is useful for NAND chips that require a stronger ECC than the i.MX
> hardware supports.
> 
> The controller normally interleaves user data with OOB data when
> accessing the NAND chip. With Software BCH ECC we write the data
> to the NAND in a way that the raw data on the NAND chip matches the
> way the NAND layer sees it. This way commands like NAND_CMD_RNDOUT
> work as expected.
> 
> This was tested on i.MX27 but should work on the other SoCs supported
> by this driver as well.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/mtd/nand/raw/mxc_nand.c | 73 ++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 68 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/mxc_nand.c b/drivers/mtd/nand/raw/mxc_nand.c
> index 6f8b8f4b118ec..ae4cff2584a2d 100644
> --- a/drivers/mtd/nand/raw/mxc_nand.c
> +++ b/drivers/mtd/nand/raw/mxc_nand.c
> @@ -1404,10 +1404,10 @@ static int mxcnd_attach_chip(struct nand_chip *chip)
>  	chip->ecc.bytes = host->devtype_data->eccbytes;
>  	host->eccsize = host->devtype_data->eccsize;
>  	chip->ecc.size = 512;
> -	mtd_set_ooblayout(mtd, host->devtype_data->ooblayout);
>  
>  	switch (chip->ecc.engine_type) {
>  	case NAND_ECC_ENGINE_TYPE_ON_HOST:
> +		mtd_set_ooblayout(mtd, host->devtype_data->ooblayout);
>  		chip->ecc.read_page = mxc_nand_read_page;
>  		chip->ecc.read_page_raw = mxc_nand_read_page_raw;
>  		chip->ecc.read_oob = mxc_nand_read_oob;
> @@ -1417,6 +1417,8 @@ static int mxcnd_attach_chip(struct nand_chip *chip)
>  		break;
>  
>  	case NAND_ECC_ENGINE_TYPE_SOFT:
> +		chip->ecc.write_page_raw = nand_monolithic_write_page_raw;
> +		chip->ecc.read_page_raw = nand_monolithic_read_page_raw;
>  		break;
>  
>  	default:
> @@ -1472,6 +1474,59 @@ static int mxcnd_setup_interface(struct nand_chip *chip, int chipnr,
>  	return host->devtype_data->setup_interface(chip, chipnr, conf);
>  }
>  
> +static void copy_page_to_sram(struct mtd_info *mtd, const void *buf, int buf_len)
> +{
> +	struct nand_chip *this = mtd_to_nand(mtd);
> +	struct mxc_nand_host *host = nand_get_controller_data(this);
> +	unsigned int no_subpages = mtd->writesize / 512;
> +	int oob_per_subpage, i;
> +
> +	oob_per_subpage = (mtd->oobsize / no_subpages) & ~1;
> +
> +	/*
> +	 * During a page write the i.MX NAND controller will read 512b from
> +	 * main_area0 SRAM, then oob_per_subpage bytes from spare0 SRAM, then
> +	 * 512b from main_area1 SRAM and so on until the full page is written.
> +	 * For software ECC we want to have a 1:1 mapping between the raw page
> +	 * data on the NAND chip and the view of the NAND core. This is
> +	 * necessary to make the NAND_CMD_RNDOUT read the data it expects.
> +	 * To accomplish this we have to write the data in the order the controller
> +	 * reads it. This is reversed in copy_page_from_sram() below.
> +	 */
> +	for (i = 0; i < no_subpages; i++) {
> +		memcpy16_toio(host->main_area0 + i * 512, buf, 512);
> +		buf += 512;
> +
> +		memcpy16_toio(host->spare0 + i * host->devtype_data->spare_len, buf,
> +			      oob_per_subpage);
> +		buf += oob_per_subpage;
> +	}
> +}

I noticed the nandbiterr test won't work with this. It needs the following
fixup. The problem is that the core wants to write only user data
without OOB, so we have to make sure the remaining SRAM is filled up
with 0xff.

I'll wait some time for other comments before sending a v4 with this
included.

Sascha

-----------------------------8<--------------------------------

From 8287fc3b44c22811350467f00b5652c94a816a36 Mon Sep 17 00:00:00 2001
From: Sascha Hauer <s.hauer@pengutronix.de>
Date: Wed, 15 May 2024 10:25:29 +0200
Subject: [PATCH] fixup! mtd: nand: mxc_nand: support software ECC

---
 drivers/mtd/nand/raw/mxc_nand.c | 35 ++++++++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/raw/mxc_nand.c b/drivers/mtd/nand/raw/mxc_nand.c
index ae4cff2584a2d..9d50f41b3d5a1 100644
--- a/drivers/mtd/nand/raw/mxc_nand.c
+++ b/drivers/mtd/nand/raw/mxc_nand.c
@@ -1474,6 +1474,15 @@ static int mxcnd_setup_interface(struct nand_chip *chip, int chipnr,
 	return host->devtype_data->setup_interface(chip, chipnr, conf);
 }
 
+static void memff16_toio(void *buf, int n)
+{
+	__iomem u16 *t = buf;
+	int i;
+
+	for (i = 0; i < (n >> 1); i++)
+		__raw_writew(0xffff, t++);
+}
+
 static void copy_page_to_sram(struct mtd_info *mtd, const void *buf, int buf_len)
 {
 	struct nand_chip *this = mtd_to_nand(mtd);
@@ -1492,14 +1501,34 @@ static void copy_page_to_sram(struct mtd_info *mtd, const void *buf, int buf_len
 	 * necessary to make the NAND_CMD_RNDOUT read the data it expects.
 	 * To accomplish this we have to write the data in the order the controller
 	 * reads it. This is reversed in copy_page_from_sram() below.
+	 *
+	 * buf_len can either be the full page including the OOB or user data only.
+	 * When it's user data only make sure that we fill up the rest of the
+	 * SRAM with 0xff.
 	 */
 	for (i = 0; i < no_subpages; i++) {
-		memcpy16_toio(host->main_area0 + i * 512, buf, 512);
+		int now = min(buf_len, 512);
+
+		if (now)
+			memcpy16_toio(host->main_area0 + i * 512, buf, now);
+
+		if (now < 512)
+			memff16_toio(host->main_area0 + i * 512 + now, 512 - now);
+
 		buf += 512;
+		buf_len -= now;
+
+		now = min(buf_len, oob_per_subpage);
+		if (now)
+			memcpy16_toio(host->spare0 + i * host->devtype_data->spare_len,
+				      buf, now);
+
+		if (now < oob_per_subpage)
+			memff16_toio(host->spare0 + i * host->devtype_data->spare_len + now,
+				     oob_per_subpage - now);
 
-		memcpy16_toio(host->spare0 + i * host->devtype_data->spare_len, buf,
-			      oob_per_subpage);
 		buf += oob_per_subpage;
+		buf_len -= now;
 	}
 }
 
-- 
2.39.2



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Re: [PATCH v3 3/3] mtd: nand: mxc_nand: support software ECC

[Miquel Raynal]

Hi Sascha,

> > +	/*
> > +	 * During a page write the i.MX NAND controller will read 512b from
> > +	 * main_area0 SRAM, then oob_per_subpage bytes from spare0 SRAM, then
> > +	 * 512b from main_area1 SRAM and so on until the full page is written.
> > +	 * For software ECC we want to have a 1:1 mapping between the raw page
> > +	 * data on the NAND chip and the view of the NAND core. This is
> > +	 * necessary to make the NAND_CMD_RNDOUT read the data it expects.
> > +	 * To accomplish this we have to write the data in the order the controller
> > +	 * reads it. This is reversed in copy_page_from_sram() below.
> > +	 */
> > +	for (i = 0; i < no_subpages; i++) {
> > +		memcpy16_toio(host->main_area0 + i * 512, buf, 512);
> > +		buf += 512;
> > +
> > +		memcpy16_toio(host->spare0 + i * host->devtype_data->spare_len, buf,
> > +			      oob_per_subpage);
> > +		buf += oob_per_subpage;
> > +	}
> > +}  
> 
> I noticed the nandbiterr test won't work with this. It needs the following
> fixup. The problem is that the core wants to write only user data
> without OOB, so we have to make sure the remaining SRAM is filled up
> with 0xff.

Yes. I looked rapidly at the diff, looks ok.

Thanks,
Miquèl

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