[PATCH] mtd: nand: brcmnand: fix mtd corrected bits stat

David Regan dregan at broadcom.com
Thu May 29 20:46:59 PDT 2025


Currently we attempt to get the amount of flipped bits from a hardware
location which is reset on every subpage. Instead obtain total flipped
bits stat from hardware accumulator. In addition identify the correct
maximum subpage corrected bits.

Signed-off-by: David Regan <dregan at broadcom.com>
Reviewed-by: William Zhang <william.zhang at broadcom.com>
Reviewed-by: Kamal Dasu <kamal.dasu at broadcom.com>
---
 drivers/mtd/nand/raw/brcmnand/brcmnand.c | 48 ++++++++++++++++++------
 1 file changed, 37 insertions(+), 11 deletions(-)

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index 62bdda3be92f..43ab4aedda55 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -361,6 +361,7 @@ enum brcmnand_reg {
 	BRCMNAND_CORR_COUNT,
 	BRCMNAND_CORR_EXT_ADDR,
 	BRCMNAND_CORR_ADDR,
+	BRCMNAND_READ_ERROR_COUNT,
 	BRCMNAND_UNCORR_EXT_ADDR,
 	BRCMNAND_UNCORR_ADDR,
 	BRCMNAND_SEMAPHORE,
@@ -389,6 +390,7 @@ static const u16 brcmnand_regs_v21[] = {
 	[BRCMNAND_CORR_THRESHOLD_EXT]	=     0,
 	[BRCMNAND_UNCORR_COUNT]		=     0,
 	[BRCMNAND_CORR_COUNT]		=     0,
+	[BRCMNAND_READ_ERROR_COUNT]	=     0,
 	[BRCMNAND_CORR_EXT_ADDR]	=  0x60,
 	[BRCMNAND_CORR_ADDR]		=  0x64,
 	[BRCMNAND_UNCORR_EXT_ADDR]	=  0x68,
@@ -419,6 +421,7 @@ static const u16 brcmnand_regs_v33[] = {
 	[BRCMNAND_CORR_THRESHOLD_EXT]	=     0,
 	[BRCMNAND_UNCORR_COUNT]		=     0,
 	[BRCMNAND_CORR_COUNT]		=     0,
+	[BRCMNAND_READ_ERROR_COUNT]	=     0,
 	[BRCMNAND_CORR_EXT_ADDR]	=  0x70,
 	[BRCMNAND_CORR_ADDR]		=  0x74,
 	[BRCMNAND_UNCORR_EXT_ADDR]	=  0x78,
@@ -449,6 +452,7 @@ static const u16 brcmnand_regs_v50[] = {
 	[BRCMNAND_CORR_THRESHOLD_EXT]	=     0,
 	[BRCMNAND_UNCORR_COUNT]		=     0,
 	[BRCMNAND_CORR_COUNT]		=     0,
+	[BRCMNAND_READ_ERROR_COUNT]	=     0,
 	[BRCMNAND_CORR_EXT_ADDR]	=  0x70,
 	[BRCMNAND_CORR_ADDR]		=  0x74,
 	[BRCMNAND_UNCORR_EXT_ADDR]	=  0x78,
@@ -479,6 +483,7 @@ static const u16 brcmnand_regs_v60[] = {
 	[BRCMNAND_CORR_THRESHOLD_EXT]	=  0xc4,
 	[BRCMNAND_UNCORR_COUNT]		=  0xfc,
 	[BRCMNAND_CORR_COUNT]		= 0x100,
+	[BRCMNAND_READ_ERROR_COUNT]	= 0x104,
 	[BRCMNAND_CORR_EXT_ADDR]	= 0x10c,
 	[BRCMNAND_CORR_ADDR]		= 0x110,
 	[BRCMNAND_UNCORR_EXT_ADDR]	= 0x114,
@@ -509,6 +514,7 @@ static const u16 brcmnand_regs_v71[] = {
 	[BRCMNAND_CORR_THRESHOLD_EXT]	=  0xe0,
 	[BRCMNAND_UNCORR_COUNT]		=  0xfc,
 	[BRCMNAND_CORR_COUNT]		= 0x100,
+	[BRCMNAND_READ_ERROR_COUNT]	= 0x104,
 	[BRCMNAND_CORR_EXT_ADDR]	= 0x10c,
 	[BRCMNAND_CORR_ADDR]		= 0x110,
 	[BRCMNAND_UNCORR_EXT_ADDR]	= 0x114,
@@ -539,6 +545,7 @@ static const u16 brcmnand_regs_v72[] = {
 	[BRCMNAND_CORR_THRESHOLD_EXT]	=  0xe0,
 	[BRCMNAND_UNCORR_COUNT]		=  0xfc,
 	[BRCMNAND_CORR_COUNT]		= 0x100,
+	[BRCMNAND_READ_ERROR_COUNT]	= 0x104,
 	[BRCMNAND_CORR_EXT_ADDR]	= 0x10c,
 	[BRCMNAND_CORR_ADDR]		= 0x110,
 	[BRCMNAND_UNCORR_EXT_ADDR]	= 0x114,
@@ -966,6 +973,13 @@ static inline u32 brcmnand_count_corrected(struct brcmnand_controller *ctrl)
 	return brcmnand_read_reg(ctrl, BRCMNAND_CORR_COUNT);
 }
 
+static inline u32 brcmnand_corr_total(struct brcmnand_controller *ctrl)
+{
+	if (ctrl->nand_version < 0x0600)
+		return 0;
+	return brcmnand_read_reg(ctrl, BRCMNAND_READ_ERROR_COUNT);
+}
+
 static void brcmnand_wr_corr_thresh(struct brcmnand_host *host, u8 val)
 {
 	struct brcmnand_controller *ctrl = host->ctrl;
@@ -2066,12 +2080,15 @@ static int brcmnand_dma_trans(struct brcmnand_host *host, u64 addr, u32 *buf,
  */
 static int brcmnand_read_by_pio(struct mtd_info *mtd, struct nand_chip *chip,
 				u64 addr, unsigned int trans, u32 *buf,
-				u8 *oob, u64 *err_addr)
+				u8 *oob, u64 *err_addr, unsigned int *corr)
 {
 	struct brcmnand_host *host = nand_get_controller_data(chip);
 	struct brcmnand_controller *ctrl = host->ctrl;
 	int i, ret = 0;
 
+	if (corr)
+		*corr = 0;
+
 	brcmnand_clear_ecc_addr(ctrl);
 
 	for (i = 0; i < trans; i++, addr += FC_BYTES) {
@@ -2099,13 +2116,16 @@ static int brcmnand_read_by_pio(struct mtd_info *mtd, struct nand_chip *chip,
 
 			if (*err_addr)
 				ret = -EBADMSG;
-		}
+			else {
+				*err_addr = brcmnand_get_correcc_addr(ctrl);
 
-		if (!ret) {
-			*err_addr = brcmnand_get_correcc_addr(ctrl);
+				if (*err_addr) {
+					ret = -EUCLEAN;
 
-			if (*err_addr)
-				ret = -EUCLEAN;
+					if (corr && brcmnand_count_corrected(ctrl) > *corr)
+						*corr = brcmnand_count_corrected(ctrl);
+				}
+			}
 		}
 	}
 
@@ -2173,6 +2193,8 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip,
 	int err;
 	bool retry = true;
 	bool edu_err = false;
+	unsigned int corr; /* max corrected bits per subpage */
+	bool dma = 0;
 
 	dev_dbg(ctrl->dev, "read %llx -> %p\n", (unsigned long long)addr, buf);
 
@@ -2195,14 +2217,17 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip,
 		if (has_edu(ctrl) && err_addr)
 			edu_err = true;
 
+		dma = 1;
 	} else {
 		if (oob)
 			memset(oob, 0x99, mtd->oobsize);
 
 		err = brcmnand_read_by_pio(mtd, chip, addr, trans, buf,
-					       oob, &err_addr);
+					   oob, &err_addr, &corr);
 	}
 
+	mtd->ecc_stats.corrected = brcmnand_corr_total(ctrl);
+
 	if (mtd_is_eccerr(err)) {
 		/*
 		 * On controller version and 7.0, 7.1 , DMA read after a
@@ -2240,18 +2265,19 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip,
 	}
 
 	if (mtd_is_bitflip(err)) {
-		unsigned int corrected = brcmnand_count_corrected(ctrl);
+		if (dma)
+			corr = brcmnand_count_corrected(ctrl);
 
 		/* in case of EDU correctable error we read again using PIO */
 		if (edu_err)
 			err = brcmnand_read_by_pio(mtd, chip, addr, trans, buf,
-						   oob, &err_addr);
+						   oob, &err_addr, &corr);
 
 		dev_dbg(ctrl->dev, "corrected error at 0x%llx\n",
 			(unsigned long long)err_addr);
-		mtd->ecc_stats.corrected += corrected;
+
 		/* Always exceed the software-imposed threshold */
-		return max(mtd->bitflip_threshold, corrected);
+		return max(mtd->bitflip_threshold, corr);
 	}
 
 	return 0;
-- 
2.43.5




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