linux-kernel - [PATCH RESEND v2 3/4] mtd: spinand: repeat reading in regular mode if continuous reading fails

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250814065423.3980305-4-mikhail.kshevetskiy@iopsys.eu>
Date: Thu, 14 Aug 2025 09:54:22 +0300
From: Mikhail Kshevetskiy <mikhail.kshevetskiy@...sys.eu>
To: Miquel Raynal <miquel.raynal@...tlin.com>,
	Richard Weinberger <richard@....at>,
	Vignesh Raghavendra <vigneshr@...com>,
	Lorenzo Bianconi <lorenzo@...nel.org>,
	Ray Liu <ray.liu@...oha.com>,
	Mark Brown <broonie@...nel.org>,
	Tudor Ambarus <tudor.ambarus@...aro.org>,
	Martin Kurbanov <mmkurbanov@...utedevices.com>,
	Takahiro Kuwano <Takahiro.Kuwano@...ineon.com>,
	Cheng Ming Lin <chengminglin@...c.com.tw>,
	linux-mtd@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-spi@...r.kernel.org
Cc: Mikhail Kshevetskiy <mikhail.kshevetskiy@...sys.eu>
Subject: [PATCH RESEND v2 3/4] mtd: spinand: repeat reading in regular mode if continuous reading fails

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.

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@...sys.eu>
---
 drivers/mtd/nand/spi/core.c | 39 ++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index 0f8636047365..5528e1f72dbc 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -378,7 +378,8 @@ static int spinand_load_page_op(struct spinand_device *spinand,
 }
 
 static int spinand_read_from_cache_op(struct spinand_device *spinand,
-				      const struct nand_page_io_req *req)
+				      const struct nand_page_io_req *req,
+				      bool *controller_is_buggy)
 {
 	struct nand_device *nand = spinand_to_nand(spinand);
 	struct mtd_info *mtd = spinand_to_mtd(spinand);
@@ -430,8 +431,11 @@ 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)
+		if (nbytes && req->continuous) {
+			if (controller_is_buggy)
+				*controller_is_buggy = true;
 			return -EIO;
+		}
 	}
 
 	if (req->datalen)
@@ -646,7 +650,7 @@ int spinand_read_page(struct spinand_device *spinand,
 
 	spinand_ondie_ecc_save_status(nand, status);
 
-	ret = spinand_read_from_cache_op(spinand, req);
+	ret = spinand_read_from_cache_op(spinand, req, NULL);
 	if (ret)
 		return ret;
 
@@ -770,7 +774,8 @@ static int spinand_mtd_regular_page_read(struct mtd_info *mtd, loff_t from,
 
 static int spinand_mtd_continuous_page_read(struct mtd_info *mtd, loff_t from,
 					    struct mtd_oob_ops *ops,
-					    unsigned int *max_bitflips)
+					    unsigned int *max_bitflips,
+					    bool *controller_is_buggy)
 {
 	struct spinand_device *spinand = mtd_to_spinand(mtd);
 	struct nand_device *nand = mtd_to_nanddev(mtd);
@@ -808,7 +813,7 @@ static int spinand_mtd_continuous_page_read(struct mtd_info *mtd, loff_t from,
 		if (ret < 0)
 			goto end_cont_read;
 
-		ret = spinand_read_from_cache_op(spinand, &iter.req);
+		ret = spinand_read_from_cache_op(spinand, &iter.req, controller_is_buggy);
 		if (ret)
 			goto end_cont_read;
 
@@ -892,6 +897,7 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,
 {
 	struct spinand_device *spinand = mtd_to_spinand(mtd);
 	struct mtd_ecc_stats old_stats;
+	bool controller_is_buggy = false;
 	unsigned int max_bitflips = 0;
 	int ret;
 
@@ -899,10 +905,25 @@ 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))
-		ret = spinand_mtd_continuous_page_read(mtd, from, ops, &max_bitflips);
-	else
-		ret = spinand_mtd_regular_page_read(mtd, from, ops, &max_bitflips);
+	if (spinand_use_cont_read(mtd, from, ops)) {
+		ret = spinand_mtd_continuous_page_read(mtd, from, ops,
+						       &max_bitflips,
+						       &controller_is_buggy);
+		if (controller_is_buggy) {
+			/*
+			 * Some spi controllers may not support reading up to
+			 * erase block size. They will read less data than
+			 * expected. If this happen disable continuous mode
+			 * and repeat reading in normal mode.
+			 */
+			spinand->cont_read_possible = false;
+			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 +=
-- 
2.50.1