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 for linux-mtd@lists.infradead.org; Wed, 09 May 2018 00:27:23 +0000
From: IKEGAMI Tokunori <ikegami@allied-telesis.co.jp>
To: Boris Brezillon <boris.brezillon@bootlin.com>
CC: Brian Norris <computersforpeace@gmail.com>, Boris Brezillon
 <boris.brezillon@free-electrons.com>, Richard Weinberger <richard@nod.at>,
 Marek Vasut <marek.vasut@gmail.com>, PACKHAM Chris
 <chris.packham@alliedtelesis.co.nz>, "linux-mtd@lists.infradead.org"
 <linux-mtd@lists.infradead.org>, Cyrille Pitchen
 <cyrille.pitchen@wedev4u.fr>, David Woodhouse <dwmw2@infradead.org>, "Joakim
 Tjernlund" <joakim.tjernlund@infinera.com>
Subject: RE: [PATCH] mtd: cfi_cmdset_0002: Change erase functions to retry for
 error
Date: Wed, 9 May 2018 00:27:05 +0000
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Hi Boris-san,

Thanks for your comments.

> >   I can reproduce the flash write error by the same reproduction method=
.
> >   And the error can be resolved by the same approach fixes as below.
> >
> <http://lists.infradead.org/pipermail/linux-mtd/2018-May/080794.html>
>=20
> Hm, even the bug fix for the write path looks suspicious. BTW, you're
> only checking the last written word, so how can you be sure all other
> words have been written correctly?

  For the write buffer I think that it is enough to check only the last wor=
d.
  Since it is described by the data sheets to check the operation status.

> I don't know a lot about CFI chips,
> but are you sure this is not a timing issue (timings mis-configured on
> the controller side)?

  Yes I think that this is not a timing issue by mis-configuration.
  But it is still possible to be a timing issue but not mis-configured.
  The write and erase errors were caused by enabling CPU external sync mode=
.
  For the CPU erratum workaround the sync mode is required to be enabled.

> >   Also I am asking to him to try the original patch on this thread.
>=20
> Ok, let's wait for Joakim's feedback then.

  Noted this.

Regards,
Ikegami