From: Miquel Raynal <miquel.raynal@bootlin.com>
To: masonccyang@mxic.com.tw
Cc: bbrezillon@kernel.org, computersforpeace@gmail.com,
dwmw2@infradead.org, juliensu@mxic.com.tw,
linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
marek.vasut@gmail.com, richard@nod.at
Subject: Re: [PATCH v1] mtd: rawnand: Add Macronix NAND read retry support
Date: Mon, 13 May 2019 11:59:26 +0200 [thread overview]
Message-ID: <20190513115926.3e862566@xps13> (raw)
In-Reply-To: <OF3A216E48.80ABBB8A-ON482583F9.002A09DA-482583F9.002AD40E@mxic.com.tw>
Hi Mason,
masonccyang@mxic.com.tw wrote on Mon, 13 May 2019 15:47:53 +0800:
> Hi Miquel,
>
>
> > >
> > > >
> > > > > + if (ret)
> > > > > + pr_err("set feature failed to read retry moded:%d\n",
> mode);
> > > >
> > > > "Failed to set read retry mode: %d\n"
> > > >
> > > > I think you can abort the operation with a negative return code in
> this
> > > > case.
> > > >
> > >
> > > After set feature operation, this NAND device need a get feature
> command
> >
> > You need to add a comment for this.
>
> okay, will add this comment by next version.
>
> >
> > > or
> > > SW reset command to exit read retry mode.
> > > Therefore, set features command followed by get feature command is
> needed.
> >
> > In this case you must check first that both set and get are supported.
> >
>
> okay, thanks.
>
>
> > > > > +
> > > > > + if (mxic->reliability_func & MACRONIX_READ_RETRY_BIT) {
> > > > > + chip->read_retries = MACRONIX_READ_RETRY_MODE + 1;
> > > >
> > > > Why +1 here, I am missing something?
> > >
> > >
> > > Without + 1, read retry mode is up to 4 rather than 5.
> > > But this NAND device support read retry mode up to 5.
> > >
> >
> > If there are 5 modes, you need to set 5 to chip->read_retries, not 6.
> >
> > If only 4 modes are used, there is probably a bug in the core that
> > must be fixed, please do not workaround it in the driver!
>
>
> It seems some patches is needed in nand_base.c
> -------------------------------------------------------------------------------------
> diff --git a/drivers/mtd/nand/raw/nand_base.c
> b/drivers/mtd/nand/raw/nand_base.c
> index ddd396e..56be3a9 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -3101,7 +3101,8 @@ static int nand_setup_read_retry(struct nand_chip
> *chip, int retry_mode)
> {
> pr_debug("setting READ RETRY mode %d\n", retry_mode);
>
> - if (retry_mode >= chip->read_retries)
> + if (retry_mode > chip->read_retries)
If I understand correctly, chip->read_retries is the total number of
'modes' so the last valid mode is indeed chip->read_retries -1.
I thought the problem would come from the core but I was wrong, you
actually need a MACRONIX_NUM_READ_RETRY_MODES set to 6. Please have two
defines if you need both (the first one being something like
MACRONIX_MAXIMUM_READ_RETRY_MODE set to 5).
Thanks,
Miquèl
next prev parent reply other threads:[~2019-05-13 9:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-10 7:41 [PATCH v1] mtd: rawnand: Add Macronix NAND read retry support Mason Yang
2019-05-10 7:45 ` Miquel Raynal
[not found] ` <OF5E2BF75D.98A43E33-ON482583F6.002E7A65-482583F6.0030A2DE@mxic.com.tw>
2019-05-10 9:12 ` Miquel Raynal
[not found] ` <OF3A216E48.80ABBB8A-ON482583F9.002A09DA-482583F9.002AD40E@mxic.com.tw>
2019-05-13 9:59 ` Miquel Raynal [this message]
2019-05-14 2:16 ` masonccyang
2019-05-10 13:37 ` Thomas Petazzoni
2019-05-10 13:53 ` Miquel Raynal
2019-05-10 14:18 ` Miquel Raynal
[not found] ` <OF1EDBA487.7723094D-ON482583F9.00297ABF-482583F9.0029E3EE@mxic.com.tw>
2019-05-13 9:40 ` Thomas Petazzoni
[not found] ` <OFB5D53BFC.6B44E7E0-ON482583FA.00090982-482583FA.000A5E93@mxic.com.tw>
2019-05-14 7:41 ` Thomas Petazzoni
2019-05-15 1:30 ` masonccyang
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