Re: [PATCH] mtd: spi-nor: read 6 bytes for the ID

Huang Shijie
2014-04-16T13:57:22Z

On Wed, Apr 16, 2014 at 12:18:28PM +0200, Marek Vasut wrote:
> On Wednesday, April 16, 2014 at 03:52:03 AM, Huang Shijie wrote:
>
> [...]
>
> > > > Does the chip vendor so silly to produce such chips? :)
> > >
> > > I don't quite understand the meaning of this sentence, but the approach
> > > where we try heuristics doesn't scale.
> >
> > If two chips share the same jedec_id, it means the two chips are produced
> > from the same chip vendor, such as 0x012018 means the chip is from
> > Spansion.
> >
> > If two chips share the same 5 bytes ID, the two chips definitely are
> > produced from the same vendor.
> >
> > So my meaning is the case what are you mentioned will _not_ exit in the
> > real world. Spansion will not so silly.
>
> You do have an awful amount of trust for those things. I am better of with
> "better safe than sorry".

okay.
>
> > > > > This code should be future-proof, but if we keep adding such special
> > > > > cases, we will end up with false matches sooner or later anyway I'm
> > > > >
> > > > > afraid.
> > > > >
> > > > > What do you say we add the READID length field into the table ?
> > > >
> > > > If we add the length field into the table, we have to sort the table by
> > > > some kind of order.
> > >
> > > Why, please elaborate.
> >
> > pleas see:
> > http://lists.infradead.org/pipermail/linux-mtd/2013-December/050670.html
>
> Sorry, but this really doesn't answer my question. It's only a matter of
> correctly implementing the matching function to find a proper match.
>
> Can we get insight on this from the others please ?
>
> > If you are interested in this issue, please give us a patch.
> > What I want is making the kernel can support the s25fl128s as soon as
> > possible.
>
> Perfect, I'd prefer to support it as correctly as possible.
wait for your patch.

thanks
Huang Shijie