[PATCH 6.12.y 0/3] Backport fixes for SPI NAND on i.MX6UL

[PATCH 6.12.y 0/3] Backport fixes for SPI NAND on i.MX6UL

[Frieder Schrempf]

From: Frieder Schrempf <frieder.schrempf@kontron.de>

There are failures with our Kontron i.MX6UL boards using Macronix SPI NAND
chips on i.MX6UL that originate in the introduction of the continuous read
feature in 6.12 (631cfdd0520d19b7f4fc13b834fd9c8b46c6dbac) and the absence
of later fixes introduced in 6.18 that were never backported.

This series contains these fixes picked from mainline, applying to stable 6.12
cleanly.

Cc: stable@vger.kernel.org
Cc: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: linux-mtd@lists.infradead.org

Mikhail Kshevetskiy (3):
  mtd: spinand: fix direct mapping creation sizes
  mtd: spinand: try a regular dirmap if creating a dirmap for continuous
    reading fails
  mtd: spinand: repeat reading in regular mode if continuous reading
    fails

 drivers/mtd/nand/spi/core.c | 74 +++++++++++++++++++++++++++++--------
 1 file changed, 59 insertions(+), 15 deletions(-)

-- 
2.55.0

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[PATCH 6.12.y 1/3] mtd: spinand: fix direct mapping creation sizes

[Frieder Schrempf]

From: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>

[ Upstream commit e4a0cf9f1d90e6888e5373da3314f761024f6c97 ]

Continuous mode is only supported for data reads, thus writing
requires only single flash page mapping.

Cc: stable@vger.kernel.org
Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
---
 drivers/mtd/nand/spi/core.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index 48ac009cbaad2..a480243385e2e 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -1036,18 +1036,13 @@ static int spinand_create_dirmap(struct spinand_device *spinand,
 				 unsigned int plane)
 {
 	struct nand_device *nand = spinand_to_nand(spinand);
-	struct spi_mem_dirmap_info info = {
-		.length = nanddev_page_size(nand) +
-			  nanddev_per_page_oobsize(nand),
-	};
+	struct spi_mem_dirmap_info info = { 0 };
 	struct spi_mem_dirmap_desc *desc;
 
-	if (spinand->cont_read_possible)
-		info.length = nanddev_eraseblock_size(nand);
-
 	/* The plane number is passed in MSB just above the column address */
 	info.offset = plane << fls(nand->memorg.pagesize);
 
+	info.length = nanddev_page_size(nand) + nanddev_per_page_oobsize(nand);
 	info.op_tmpl = *spinand->op_templates.update_cache;
 	desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
 					  spinand->spimem, &info);
@@ -1056,6 +1051,8 @@ static int spinand_create_dirmap(struct spinand_device *spinand,
 
 	spinand->dirmaps[plane].wdesc = desc;
 
+	if (spinand->cont_read_possible)
+		info.length = nanddev_eraseblock_size(nand);
 	info.op_tmpl = *spinand->op_templates.read_cache;
 	desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
 					  spinand->spimem, &info);
@@ -1071,6 +1068,7 @@ static int spinand_create_dirmap(struct spinand_device *spinand,
 		return 0;
 	}
 
+	info.length = nanddev_page_size(nand) + nanddev_per_page_oobsize(nand);
 	info.op_tmpl = *spinand->op_templates.update_cache;
 	info.op_tmpl.data.ecc = true;
 	desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
@@ -1080,6 +1078,8 @@ static int spinand_create_dirmap(struct spinand_device *spinand,
 
 	spinand->dirmaps[plane].wdesc_ecc = desc;
 
+	if (spinand->cont_read_possible)
+		info.length = nanddev_eraseblock_size(nand);
 	info.op_tmpl = *spinand->op_templates.read_cache;
 	info.op_tmpl.data.ecc = true;
 	desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
-- 
2.55.0


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[PATCH 6.12.y 2/3] mtd: spinand: try a regular dirmap if creating a dirmap for continuous reading fails

[Frieder Schrempf]

From: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>

[ Upstream commit 004f8ea0d9917398aabff7388b3bf62a84a4088b ]

Continuous reading may result in multiple flash pages reading in one
operation. Typically only one flash page has read/written (a little bit
more than 2-4 Kb), but continuous reading requires the spi controller
to read up to 512 Kb in one operation without toggling CS in beetween.

Roughly speaking spi controllers can be divided on 2 categories:
 * spi controllers without dirmap acceleration support
 * spi controllers with dirmap acceleration support

Firt of them will have issues with continuous reading if restriction on
the transfer length is implemented in the adjust_op_size() handler.
Second group often supports acceleration of single page only reading.
Thus enabling of continuous reading can break flash reading.

This patch tries to create dirmap for continuous reading first and
fallback to regular reading if spi controller refuses to create it.

Cc: stable@vger.kernel.org
Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
---
 drivers/mtd/nand/spi/core.c | 43 ++++++++++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index a480243385e2e..10339209e7322 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -1032,6 +1032,39 @@ static int spinand_mtd_block_isreserved(struct mtd_info *mtd, loff_t offs)
 	return ret;
 }
 
+static struct spi_mem_dirmap_desc *spinand_create_rdesc(
+					struct spinand_device *spinand,
+					struct spi_mem_dirmap_info *info)
+{
+	struct nand_device *nand = spinand_to_nand(spinand);
+	struct spi_mem_dirmap_desc *desc = NULL;
+
+	if (spinand->cont_read_possible) {
+		/*
+		 * spi controller may return an error if info->length is
+		 * too large
+		 */
+		info->length = nanddev_eraseblock_size(nand);
+		desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
+						  spinand->spimem, info);
+	}
+
+	if (IS_ERR_OR_NULL(desc)) {
+		/*
+		 * continuous reading is not supported by flash or
+		 * its spi controller, use regular reading
+		 */
+		spinand->cont_read_possible = false;
+
+		info->length = nanddev_page_size(nand) +
+			       nanddev_per_page_oobsize(nand);
+		desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
+						  spinand->spimem, info);
+	}
+
+	return desc;
+}
+
 static int spinand_create_dirmap(struct spinand_device *spinand,
 				 unsigned int plane)
 {
@@ -1051,11 +1084,8 @@ static int spinand_create_dirmap(struct spinand_device *spinand,
 
 	spinand->dirmaps[plane].wdesc = desc;
 
-	if (spinand->cont_read_possible)
-		info.length = nanddev_eraseblock_size(nand);
 	info.op_tmpl = *spinand->op_templates.read_cache;
-	desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
-					  spinand->spimem, &info);
+	desc = spinand_create_rdesc(spinand, &info);
 	if (IS_ERR(desc))
 		return PTR_ERR(desc);
 
@@ -1078,12 +1108,9 @@ static int spinand_create_dirmap(struct spinand_device *spinand,
 
 	spinand->dirmaps[plane].wdesc_ecc = desc;
 
-	if (spinand->cont_read_possible)
-		info.length = nanddev_eraseblock_size(nand);
 	info.op_tmpl = *spinand->op_templates.read_cache;
 	info.op_tmpl.data.ecc = true;
-	desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
-					  spinand->spimem, &info);
+	desc = spinand_create_rdesc(spinand, &info);
 	if (IS_ERR(desc))
 		return PTR_ERR(desc);
 
-- 
2.55.0


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[PATCH 6.12.y 3/3] mtd: spinand: repeat reading in regular mode if continuous reading fails

[Frieder Schrempf]

From: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>

[ Upstream commit 010dc7f2dd6a0078ade3f88f627ed5fbf45ceb94 ]

Continuous reading may result in multiple flash pages reading in one
operation. Unfortunately, not all spinand controllers support such
large reading. They will read less data. Unfortunately, the operation
can't be continued.

In this case:
 * disable continuous reading on this (not good enough) spi controller
 * repeat reading in regular mode.

Cc: stable@vger.kernel.org
Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
---
 drivers/mtd/nand/spi/core.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index 10339209e7322..bf16901b77b64 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -427,8 +427,16 @@ static int spinand_read_from_cache_op(struct spinand_device *spinand,
 		 * Dirmap accesses are allowed to toggle the CS.
 		 * Toggling the CS during a continuous read is forbidden.
 		 */
-		if (nbytes && req->continuous)
-			return -EIO;
+		if (nbytes && req->continuous) {
+			/*
+			 * Spi controller with broken support of continuous
+			 * reading was detected. Disable future use of
+			 * continuous reading and return -EAGAIN to retry
+			 * reading within regular mode.
+			 */
+			spinand->cont_read_possible = false;
+			return -EAGAIN;
+		}
 	}
 
 	if (req->datalen)
@@ -849,10 +857,19 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,
 
 	old_stats = mtd->ecc_stats;
 
-	if (spinand_use_cont_read(mtd, from, ops))
+	if (spinand_use_cont_read(mtd, from, ops)) {
 		ret = spinand_mtd_continuous_page_read(mtd, from, ops, &max_bitflips);
-	else
+		if (ret == -EAGAIN && !spinand->cont_read_possible) {
+			/*
+			 * Spi controller with broken support of continuous
+			 * reading was detected (see spinand_read_from_cache_op()),
+			 * repeat reading in regular mode.
+			 */
+			ret = spinand_mtd_regular_page_read(mtd, from, ops, &max_bitflips);
+		}
+	} else {
 		ret = spinand_mtd_regular_page_read(mtd, from, ops, &max_bitflips);
+	}
 
 	if (ops->stats) {
 		ops->stats->uncorrectable_errors +=
-- 
2.55.0


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Re: [PATCH 6.12.y 0/3] Backport fixes for SPI NAND on i.MX6UL

[Miquel Raynal]

> This series contains these fixes picked from mainline, applying to stable 6.12
> cleanly.
>
> Cc: stable@vger.kernel.org
> Cc: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: linux-mtd@lists.infradead.org
>
> Mikhail Kshevetskiy (3):
>   mtd: spinand: fix direct mapping creation sizes
>   mtd: spinand: try a regular dirmap if creating a dirmap for continuous
>     reading fails
>   mtd: spinand: repeat reading in regular mode if continuous reading
>     fails
>
>  drivers/mtd/nand/spi/core.c | 74 +++++++++++++++++++++++++++++--------
>  1 file changed, 59 insertions(+), 15 deletions(-)

Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks for the backports,
Miquèl

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