[PATCH] mtd: cfi_cmdset_0002: Change erase functions to retry for error

[IKEGAMI Tokunori]

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>
> 
> 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 word.
  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.
> 
> Ok, let's wait for Joakim's feedback then.

  Noted this.

Regards,
Ikegami