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[PATCH 2/2] mtd: spi-nand: Add read retry support

Cheng Ming Lin posted 2 patches 1 year, 3 months ago
[PATCH 2/2] mtd: spi-nand: Add read retry support
Posted by Cheng Ming Lin 1 year, 3 months ago 
From: Cheng Ming Lin <chengminglin@mxic.com.tw>

When the host ECC fails to correct the data error of NAND device,
there's a special read for data recovery method which host setups
for the next read retry mode and may recover the lost data by host
ECC again.

Signed-off-by: Cheng Ming Lin <chengminglin@mxic.com.tw>
---
 drivers/mtd/nand/spi/core.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index e0b6715e5dfe..2f21ea926132 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -640,6 +640,7 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,
 	struct nand_io_iter iter;
 	bool disable_ecc = false;
 	bool ecc_failed = false;
+	u8 retry_mode = 0;
 	int ret = 0;
 
 	if (ops->mode == MTD_OPS_RAW || !spinand->eccinfo.ooblayout)
@@ -657,20 +658,45 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,
 		if (ret)
 			break;
 
+read_retry:
 		ret = spinand_read_page(spinand, &iter.req);
 		if (ret < 0 && ret != -EBADMSG)
 			break;
 
-		if (ret == -EBADMSG)
+		if (ret == -EBADMSG && spinand->info->fixups) {
+			if (spinand->read_retries && ((retry_mode + 1) < spinand->read_retries)) {
+				retry_mode++;
+				ret = spinand->info->fixups->setup_read_retry(spinand, retry_mode);
+				if (ret < 0)
+					break;
+
+				/* Reset ecc_stats; retry */
+				mtd->ecc_stats = old_stats;
+				goto read_retry;
+			} else {
+				/* No more retry modes; real failure */
+				ecc_failed = true;
+			}
+		} else if (ret == -EBADMSG) {
 			ecc_failed = true;
-		else
+		} else {
 			max_bitflips = max_t(unsigned int, max_bitflips, ret);
+		}
 
 		ret = 0;
 		ops->retlen += iter.req.datalen;
 		ops->oobretlen += iter.req.ooblen;
+
+		/* Reset to retry mode 0*/
+		if (retry_mode) {
+			ret = spinand->info->fixups->setup_read_retry(spinand, 0);
+			if (ret < 0)
+				break;
+			retry_mode = 0;
+		}
 	}
 
+
 	if (ops->stats) {
 		ops->stats->uncorrectable_errors +=
 			mtd->ecc_stats.failed - old_stats.failed;
@@ -1095,6 +1121,9 @@ int spinand_match_and_init(struct spinand_device *spinand,
 		spinand->flags = table[i].flags;
 		spinand->id.len = 1 + table[i].devid.len;
 		spinand->select_target = table[i].select_target;
+		spinand->info = info;
+		if (spinand->info->fixups && spinand->info->fixups->init_read_retry)
+			spinand->read_retries = spinand->info->fixups->init_read_retry(spinand);
 
 		op = spinand_select_op_variant(spinand,
 					       info->op_variants.read_cache);
-- 
2.25.1
Re: [PATCH 2/2] mtd: spi-nand: Add read retry support
Posted by Miquel Raynal 1 year, 2 months ago 
Hi Cheng Ming,

linchengming884@gmail.com wrote on Thu,  5 Sep 2024 13:53:33 +0800:

> From: Cheng Ming Lin <chengminglin@mxic.com.tw>
> 
> When the host ECC fails to correct the data error of NAND device,
> there's a special read for data recovery method which host setups
> for the next read retry mode and may recover the lost data by host
> ECC again.
> 
> Signed-off-by: Cheng Ming Lin <chengminglin@mxic.com.tw>
> ---
>  drivers/mtd/nand/spi/core.c | 33 +++++++++++++++++++++++++++++++--
>  1 file changed, 31 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
> index e0b6715e5dfe..2f21ea926132 100644
> --- a/drivers/mtd/nand/spi/core.c
> +++ b/drivers/mtd/nand/spi/core.c
> @@ -640,6 +640,7 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,
>  	struct nand_io_iter iter;
>  	bool disable_ecc = false;
>  	bool ecc_failed = false;
> +	u8 retry_mode = 0;
>  	int ret = 0;
>  
>  	if (ops->mode == MTD_OPS_RAW || !spinand->eccinfo.ooblayout)
> @@ -657,20 +658,45 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,

This will no longer apply with continuous support added in. However
please make this only in the non continuous path. I don't think it can
fly in the other.

>  		if (ret)
>  			break;
>  
> +read_retry:
>  		ret = spinand_read_page(spinand, &iter.req);
>  		if (ret < 0 && ret != -EBADMSG)
>  			break;
>  
> -		if (ret == -EBADMSG)
> +		if (ret == -EBADMSG && spinand->info->fixups) {
> +			if (spinand->read_retries && ((retry_mode + 1) < spinand->read_retries)) {

							++retry_mode?
> +				retry_mode++;

So this can be dropped.

> +				ret = spinand->info->fixups->setup_read_retry(spinand, retry_mode);
> +				if (ret < 0)
> +					break;

No, you need to set ecc_failed here.

> +
> +				/* Reset ecc_stats; retry */
> +				mtd->ecc_stats = old_stats;
> +				goto read_retry;
> +			} else {
> +				/* No more retry modes; real failure */
> +				ecc_failed = true;
> +			}
> +		} else if (ret == -EBADMSG) {
>  			ecc_failed = true;
> -		else
> +		} else {
>  			max_bitflips = max_t(unsigned int, max_bitflips, ret);
> +		}
>  
>  		ret = 0;
>  		ops->retlen += iter.req.datalen;
>  		ops->oobretlen += iter.req.ooblen;
> +
> +		/* Reset to retry mode 0*/
> +		if (retry_mode) {

			retry_mode = 0;

> +			ret = spinand->info->fixups->setup_read_retry(spinand, 0);

									retry_mode);

> +			if (ret < 0)
> +				break;

this if clause is useless.

> +			retry_mode = 0;

And then this can be dropped from here.

> +		}
>  	}
>  
> +

Spurious line

>  	if (ops->stats) {
>  		ops->stats->uncorrectable_errors +=
>  			mtd->ecc_stats.failed - old_stats.failed;
> @@ -1095,6 +1121,9 @@ int spinand_match_and_init(struct spinand_device *spinand,
>  		spinand->flags = table[i].flags;
>  		spinand->id.len = 1 + table[i].devid.len;
>  		spinand->select_target = table[i].select_target;
> +		spinand->info = info;
> +		if (spinand->info->fixups && spinand->info->fixups->init_read_retry)
> +			spinand->read_retries = spinand->info->fixups->init_read_retry(spinand);

Now I get you init. Ok, fine.

>  
>  		op = spinand_select_op_variant(spinand,
>  					       info->op_variants.read_cache);


Thanks,
Miquèl
Re: [PATCH 2/2] mtd: spi-nand: Add read retry support
Posted by Cheng Ming Lin 1 year, 2 months ago 
Hi Miquel,

Miquel Raynal <miquel.raynal@bootlin.com> 於 2024年10月1日 週二 下午6:17寫道：
>
> Hi Cheng Ming,
>
> linchengming884@gmail.com wrote on Thu,  5 Sep 2024 13:53:33 +0800:
>
> > From: Cheng Ming Lin <chengminglin@mxic.com.tw>
> >
> > When the host ECC fails to correct the data error of NAND device,
> > there's a special read for data recovery method which host setups
> > for the next read retry mode and may recover the lost data by host
> > ECC again.
> >
> > Signed-off-by: Cheng Ming Lin <chengminglin@mxic.com.tw>
> > ---
> >  drivers/mtd/nand/spi/core.c | 33 +++++++++++++++++++++++++++++++--
> >  1 file changed, 31 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
> > index e0b6715e5dfe..2f21ea926132 100644
> > --- a/drivers/mtd/nand/spi/core.c
> > +++ b/drivers/mtd/nand/spi/core.c
> > @@ -640,6 +640,7 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,
> >       struct nand_io_iter iter;
> >       bool disable_ecc = false;
> >       bool ecc_failed = false;
> > +     u8 retry_mode = 0;
> >       int ret = 0;
> >
> >       if (ops->mode == MTD_OPS_RAW || !spinand->eccinfo.ooblayout)
> > @@ -657,20 +658,45 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,
>
> This will no longer apply with continuous support added in. However
> please make this only in the non continuous path. I don't think it can
> fly in the other.

Thanks for your helpful suggestions.

>
> >               if (ret)
> >                       break;
> >
> > +read_retry:
> >               ret = spinand_read_page(spinand, &iter.req);
> >               if (ret < 0 && ret != -EBADMSG)
> >                       break;
> >
> > -             if (ret == -EBADMSG)
> > +             if (ret == -EBADMSG && spinand->info->fixups) {
> > +                     if (spinand->read_retries && ((retry_mode + 1) < spinand->read_retries)) {
>
>                                                         ++retry_mode?
> > +                             retry_mode++;
>
> So this can be dropped.
>
> > +                             ret = spinand->info->fixups->setup_read_retry(spinand, retry_mode);
> > +                             if (ret < 0)
> > +                                     break;
>
> No, you need to set ecc_failed here.
>
> > +
> > +                             /* Reset ecc_stats; retry */
> > +                             mtd->ecc_stats = old_stats;
> > +                             goto read_retry;
> > +                     } else {
> > +                             /* No more retry modes; real failure */
> > +                             ecc_failed = true;
> > +                     }
> > +             } else if (ret == -EBADMSG) {
> >                       ecc_failed = true;
> > -             else
> > +             } else {
> >                       max_bitflips = max_t(unsigned int, max_bitflips, ret);
> > +             }
> >
> >               ret = 0;
> >               ops->retlen += iter.req.datalen;
> >               ops->oobretlen += iter.req.ooblen;
> > +
> > +             /* Reset to retry mode 0*/
> > +             if (retry_mode) {
>
>                         retry_mode = 0;
>
> > +                     ret = spinand->info->fixups->setup_read_retry(spinand, 0);
>
>                                                                         retry_mode);
>
> > +                     if (ret < 0)
> > +                             break;
>
> this if clause is useless.
>
> > +                     retry_mode = 0;
>
> And then this can be dropped from here.
>
> > +             }
> >       }
> >
> > +
>
> Spurious line
>
> >       if (ops->stats) {
> >               ops->stats->uncorrectable_errors +=
> >                       mtd->ecc_stats.failed - old_stats.failed;
> > @@ -1095,6 +1121,9 @@ int spinand_match_and_init(struct spinand_device *spinand,
> >               spinand->flags = table[i].flags;
> >               spinand->id.len = 1 + table[i].devid.len;
> >               spinand->select_target = table[i].select_target;
> > +             spinand->info = info;
> > +             if (spinand->info->fixups && spinand->info->fixups->init_read_retry)
> > +                     spinand->read_retries = spinand->info->fixups->init_read_retry(spinand);
>
> Now I get you init. Ok, fine.
>
> >
> >               op = spinand_select_op_variant(spinand,
> >                                              info->op_variants.read_cache);
>

Thank you for all your suggestions.
I will modify the patch according to your advice.

>
> Thanks,
> Miquèl

Thanks,
Cheng Ming Lin

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