From: Florian Fainelli <florian@openwrt.org>
To: "Rafał Miłecki" <zajec5@gmail.com>
Cc: linux-wireless@vger.kernel.org,
"John W. Linville" <linville@tuxdriver.com>,
Larry Finger <Larry.Finger@lwfinger.net>,
Hauke Mehrtens <hauke@hauke-m.de>
Subject: Re: [PATCH V2] bcma: add basic NAND flash driver
Date: Mon, 06 Aug 2012 10:50:15 +0200 [thread overview]
Message-ID: <1673359.JloXiOZbAj@flexo> (raw)
In-Reply-To: <CACna6rzFeX5rHVxZSpFVwL1psLBfuWK-X8_YAZdtLDFbNKjPPQ@mail.gmail.com>
Hello Rafal,
On Monday 06 August 2012 08:50:35 Rafał Miłecki wrote:
> Thanks for looking at this!
>
> 2012/8/5 Florian Fainelli <florian@openwrt.org>:
> > Le dimanche 05 août 2012 22:03:07, Rafał Miłecki a écrit :
> >> This is basic driver for NAND flash memory that allows reading it's
> >> content. It was succesfully tested on Netgear WNDR4500 which is BCM4706
> >> based router.
> >>
> >> This driver has been written using specs at:
> >> http://bcm-v4.sipsolutions.net/NAND_Flash
> >
> > The big problem that I see with your driver is that it does not interface
with
> > the MTD subsystem, and therefore:
> >
> > - does not conform to the MTD API for reading pages, blocks etc...
>
> My idea for bcma responsibilities consists of:
> 1) Detecting hardware
> 2) Providing basic access to it
> This is what (I believe) I provided with that submitted patch.
>
> I'm not registering MTD driver directly in bcma, just like we don't
> register ieee80211 device for 80211 core or netdev for ETH core.
>
> After providing basic/low-level access in bcma my plan is to write
> real MTD driver. In this driver I could make use of functions from
> bcma_chipcommon_nflash.[ch].
>
> Does it sound better now?
A little, but I still wonder why this would be needed at all, unless you
cannot rely on MTD because you are doing stuff very early with the Flash.
I find perfectly legitimate to export some bcma-specific symbols for accessing
the NAND flash controller, but am a little more dubious about duplicating the
reading/detection.
>
>
> > - duplicates NAND flash detection in a manner which is far less robust than
> > what the MTD NAND subsystem already does
>
> Hm, do you mean there is some MTD driver detecting NAND flash on BCMA?
> I wasn't aware of that. Grepping drivers/mtd for "bcma" didn't give me
> anything. Can you say something more about this?
No I meant that all the ID code decoding to determine the chip size,
manufacturer etc ... is already well handled within MTD.
>
>
> > I guess that this driver enables you do some stuff on your router, but
clearly
> > you should aim at writing a real MTD driver instead of having such an ad-
hoc
> > solution.
>
> That "do some stuff" means almost nothing right now. My plan (as
> explained earlier) is to write MTD driver.
Ok, well maybe I should just let you write your MTD driver and we see how that
interfaces with this current patch.
>
> --
> Rafał
next prev parent reply other threads:[~2012-08-06 8:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-05 20:03 [PATCH V2] bcma: add basic NAND flash driver Rafał Miłecki
2012-08-05 20:40 ` Florian Fainelli
2012-08-06 6:50 ` Rafał Miłecki
2012-08-06 8:50 ` Florian Fainelli [this message]
2012-08-06 12:08 ` Rafał Miłecki
2012-08-06 23:27 ` Hauke Mehrtens
2012-08-06 9:12 ` Florian Fainelli
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