mtd: rawnand: marvell: pass ms delay to wait_op
diff mbox series

Message ID 20180503022128.10702-1-chris.packham@alliedtelesis.co.nz
State Accepted
Delegated to: Boris Brezillon
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Series
  • mtd: rawnand: marvell: pass ms delay to wait_op
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Commit Message

Chris Packham May 3, 2018, 2:21 a.m. UTC
marvell_nfc_wait_op() expects the delay to be expressed in milliseconds
but nand_sdr_timings uses picoseconds. Use PSEC_TO_MSEC when passing
tPROG_max to marvell_nfc_wait_op().

Fixes: 02f26ecf8c772 ("mtd: nand: add reworked Marvell NAND controller driver")
Cc: stable@vger.kernel.org
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
 drivers/mtd/nand/raw/marvell_nand.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Chris Packham May 3, 2018, 5:28 a.m. UTC | #1
On 03/05/18 14:21, Chris Packham wrote:
> marvell_nfc_wait_op() expects the delay to be expressed in milliseconds
> but nand_sdr_timings uses picoseconds. Use PSEC_TO_MSEC when passing
> tPROG_max to marvell_nfc_wait_op().
> 
> Fixes: 02f26ecf8c772 ("mtd: nand: add reworked Marvell NAND controller driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
>   drivers/mtd/nand/raw/marvell_nand.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
> index 1d779a35ac8e..e4b964fd40d8 100644
> --- a/drivers/mtd/nand/raw/marvell_nand.c
> +++ b/drivers/mtd/nand/raw/marvell_nand.c
> @@ -1074,7 +1074,7 @@ static int marvell_nfc_hw_ecc_hmg_do_write_page(struct nand_chip *chip,
>   		return ret;
>   
>   	ret = marvell_nfc_wait_op(chip,
> -				  chip->data_interface.timings.sdr.tPROG_max);
> +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
>   	return ret;
>   }
>   
> @@ -1494,7 +1494,7 @@ static int marvell_nfc_hw_ecc_bch_write_page(struct mtd_info *mtd,
>   	}
>   
>   	ret = marvell_nfc_wait_op(chip,
> -				  chip->data_interface.timings.sdr.tPROG_max);
> +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
>   
>   	marvell_nfc_disable_hw_ecc(chip);
>   

Actually I'm not so sure about this patch. While passing the pico-second 
value for tPROG_max is clearly wrong and leads to seemingly indefinite 
hangs on some systems. Converting the times to micro-seconds leaves us 
with delays that are far too short.

The old pxa3xx driver had hard coded 200ms delays. These delays now work 
out to 1ms which seems every bit as wrong as 600000000ms.
Boris Brezillon May 3, 2018, 7:03 a.m. UTC | #2
Hi Chris,

On Thu, 3 May 2018 05:28:32 +0000
Chris Packham <Chris.Packham@alliedtelesis.co.nz> wrote:

> On 03/05/18 14:21, Chris Packham wrote:
> > marvell_nfc_wait_op() expects the delay to be expressed in milliseconds
> > but nand_sdr_timings uses picoseconds. Use PSEC_TO_MSEC when passing
> > tPROG_max to marvell_nfc_wait_op().
> > 
> > Fixes: 02f26ecf8c772 ("mtd: nand: add reworked Marvell NAND controller driver")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> > ---
> >   drivers/mtd/nand/raw/marvell_nand.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
> > index 1d779a35ac8e..e4b964fd40d8 100644
> > --- a/drivers/mtd/nand/raw/marvell_nand.c
> > +++ b/drivers/mtd/nand/raw/marvell_nand.c
> > @@ -1074,7 +1074,7 @@ static int marvell_nfc_hw_ecc_hmg_do_write_page(struct nand_chip *chip,
> >   		return ret;
> >   
> >   	ret = marvell_nfc_wait_op(chip,
> > -				  chip->data_interface.timings.sdr.tPROG_max);
> > +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
> >   	return ret;
> >   }
> >   
> > @@ -1494,7 +1494,7 @@ static int marvell_nfc_hw_ecc_bch_write_page(struct mtd_info *mtd,
> >   	}
> >   
> >   	ret = marvell_nfc_wait_op(chip,
> > -				  chip->data_interface.timings.sdr.tPROG_max);
> > +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
> >   
> >   	marvell_nfc_disable_hw_ecc(chip);
> >     
> 
> Actually I'm not so sure about this patch. While passing the pico-second 
> value for tPROG_max is clearly wrong and leads to seemingly indefinite 
> hangs on some systems. Converting the times to micro-seconds leaves us 
> with delays that are far too short.

What makes you think they are far too short?

> 
> The old pxa3xx driver had hard coded 200ms delays. These delays now work 
> out to 1ms which seems every bit as wrong as 600000000ms.

The old driver was indifferently waiting a huge amount of time no
matter how long the chip is supposed to stay busy for a specific
operation. Here we're using the value exposed by the chip itself, and
it's not a typical value, it's a max value, which means you should
never reach that in real life, and if you do that means your chip is
stuck for some reasons. Now, if you want to take extra safety margin,
you can multiply the value by 2 and that should be enough, but 200ms is
way too long.

Regards,

Boris
Miquel Raynal May 3, 2018, 7:05 a.m. UTC | #3
Hi Chris,

On Thu, 3 May 2018 05:28:32 +0000, Chris Packham
<Chris.Packham@alliedtelesis.co.nz> wrote:

> On 03/05/18 14:21, Chris Packham wrote:
> > marvell_nfc_wait_op() expects the delay to be expressed in milliseconds
> > but nand_sdr_timings uses picoseconds. Use PSEC_TO_MSEC when passing
> > tPROG_max to marvell_nfc_wait_op().
> > 
> > Fixes: 02f26ecf8c772 ("mtd: nand: add reworked Marvell NAND controller driver")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> > ---
> >   drivers/mtd/nand/raw/marvell_nand.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
> > index 1d779a35ac8e..e4b964fd40d8 100644
> > --- a/drivers/mtd/nand/raw/marvell_nand.c
> > +++ b/drivers/mtd/nand/raw/marvell_nand.c
> > @@ -1074,7 +1074,7 @@ static int marvell_nfc_hw_ecc_hmg_do_write_page(struct nand_chip *chip,
> >   		return ret;
> >   
> >   	ret = marvell_nfc_wait_op(chip,
> > -				  chip->data_interface.timings.sdr.tPROG_max);
> > +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
> >   	return ret;
> >   }
> >   
> > @@ -1494,7 +1494,7 @@ static int marvell_nfc_hw_ecc_bch_write_page(struct mtd_info *mtd,
> >   	}
> >   
> >   	ret = marvell_nfc_wait_op(chip,
> > -				  chip->data_interface.timings.sdr.tPROG_max);
> > +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
> >   
> >   	marvell_nfc_disable_hw_ecc(chip);
> >     
> 
> Actually I'm not so sure about this patch. While passing the pico-second 
> value for tPROG_max is clearly wrong and leads to seemingly indefinite 
> hangs on some systems. Converting the times to micro-seconds leaves us 
> with delays that are far too short.

It is not micro but milli-seconds here.

> 
> The old pxa3xx driver had hard coded 200ms delays. These delays now work 
> out to 1ms which seems every bit as wrong as 600000000ms.

200ms is extremely long, I guess typical values are ~200-500us, so this
1ms timeout does not scare me :)

I'll let Boris conclude.

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

Thanks.
Miquel Raynal May 3, 2018, 8:01 a.m. UTC | #4
Hi Boris, Chris,

> > > diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
> > > index 1d779a35ac8e..e4b964fd40d8 100644
> > > --- a/drivers/mtd/nand/raw/marvell_nand.c
> > > +++ b/drivers/mtd/nand/raw/marvell_nand.c
> > > @@ -1074,7 +1074,7 @@ static int marvell_nfc_hw_ecc_hmg_do_write_page(struct nand_chip *chip,
> > >   		return ret;
> > >   
> > >   	ret = marvell_nfc_wait_op(chip,
> > > -				  chip->data_interface.timings.sdr.tPROG_max);
> > > +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
> > >   	return ret;
> > >   }
> > >   
> > > @@ -1494,7 +1494,7 @@ static int marvell_nfc_hw_ecc_bch_write_page(struct mtd_info *mtd,
> > >   	}
> > >   
> > >   	ret = marvell_nfc_wait_op(chip,
> > > -				  chip->data_interface.timings.sdr.tPROG_max);
> > > +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
> > >   

[...]

> > The old pxa3xx driver had hard coded 200ms delays. These delays now work 
> > out to 1ms which seems every bit as wrong as 600000000ms.  

When the 'keep-config' property is populated, the
->setup_data_interface() hook of the driver is not shown to the core,
which leads to not "updating" the timings like tPROG_max.

While it worked with the old driver that hardcoded this delay, this
might not work anymore with the current driver because it expects
timings.sdr.tPROG_max to be != 0 (and PSEC_TO_MSEC(0) also returns 0).

This is probably something to fix.

Regards,
Miquèl
Boris Brezillon May 7, 2018, 7:41 a.m. UTC | #5
On Thu,  3 May 2018 14:21:28 +1200
Chris Packham <chris.packham@alliedtelesis.co.nz> wrote:

> marvell_nfc_wait_op() expects the delay to be expressed in milliseconds
> but nand_sdr_timings uses picoseconds. Use PSEC_TO_MSEC when passing
> tPROG_max to marvell_nfc_wait_op().
> 
> Fixes: 02f26ecf8c772 ("mtd: nand: add reworked Marvell NAND controller driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>

Queued to mtd/fixes.

Thanks,

Boris

> ---
>  drivers/mtd/nand/raw/marvell_nand.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
> index 1d779a35ac8e..e4b964fd40d8 100644
> --- a/drivers/mtd/nand/raw/marvell_nand.c
> +++ b/drivers/mtd/nand/raw/marvell_nand.c
> @@ -1074,7 +1074,7 @@ static int marvell_nfc_hw_ecc_hmg_do_write_page(struct nand_chip *chip,
>  		return ret;
>  
>  	ret = marvell_nfc_wait_op(chip,
> -				  chip->data_interface.timings.sdr.tPROG_max);
> +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
>  	return ret;
>  }
>  
> @@ -1494,7 +1494,7 @@ static int marvell_nfc_hw_ecc_bch_write_page(struct mtd_info *mtd,
>  	}
>  
>  	ret = marvell_nfc_wait_op(chip,
> -				  chip->data_interface.timings.sdr.tPROG_max);
> +				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
>  
>  	marvell_nfc_disable_hw_ecc(chip);
>

Patch
diff mbox series

diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
index 1d779a35ac8e..e4b964fd40d8 100644
--- a/drivers/mtd/nand/raw/marvell_nand.c
+++ b/drivers/mtd/nand/raw/marvell_nand.c
@@ -1074,7 +1074,7 @@  static int marvell_nfc_hw_ecc_hmg_do_write_page(struct nand_chip *chip,
 		return ret;
 
 	ret = marvell_nfc_wait_op(chip,
-				  chip->data_interface.timings.sdr.tPROG_max);
+				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
 	return ret;
 }
 
@@ -1494,7 +1494,7 @@  static int marvell_nfc_hw_ecc_bch_write_page(struct mtd_info *mtd,
 	}
 
 	ret = marvell_nfc_wait_op(chip,
-				  chip->data_interface.timings.sdr.tPROG_max);
+				  PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
 
 	marvell_nfc_disable_hw_ecc(chip);