From: Sascha Hauer <s.hauer@pengutronix.de>
To: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: barebox@lists.infradead.org, Krzysztof Halasa <khc@pm.waw.pl>
Subject: Re: IXP4xx support
Date: Mon, 8 Feb 2010 14:40:16 +0100 [thread overview]
Message-ID: <20100208134016.GB17643@pengutronix.de> (raw)
In-Reply-To: <4B6E9AEE.7040506@pengutronix.de>
On Sun, Feb 07, 2010 at 11:50:22AM +0100, Marc Kleine-Budde wrote:
> Krzysztof Halasa wrote:
> > I'm thinking about adding Barebox support for a certain platform using
> > IXP425 (ARM, usually big-endian) CPU. This means the startup code
> > (trivial, already got it working in little-endian mode), drivers for
> > hardware Queue Manager, Network Processing Engines and built-in Ethernet
> > interfaces (all of them easy to port from Linux).
> >
> > This also means supporting the NOR flash: the CPU has 16-bit, always
> > big-endian, "value-preserving" EXP bus for connecting such devices. In
> > LE mode the address has to be XORed with 2, and if it's byte-oriented
> > data (i.e. not a command/response), it has to be byte-swapped. Only
> > 16-bit writes can be made.
> >
> > Doing the above in the flash driver would complicate things a lot. The
> > drivers currently use plain pointers to access the flash. I'm thinking
> > about moving the low-level access (R/W) routines to arch code (with a
> > generic defaults), and calling them via the NOR flash platform struct
> > (which doesn't do anything useful ATM).
>
> have a look at the current uboot cfi flash driver. They have read/write
> functions to access the flash. By default they are macros to IIRC
> __raw_read,write.
>
> From the first look, the driver looks much cleaner than the "old" one
> used in barebox (modulo my bugfix from last week).
It seems it still has the same driver under the hood.
I suggest to remove the "old" driver in favor for the cfi_flash_new
driver so that this ongoing confusion ends and Krzysztof has some base
to work on. I think the flash accesses can be ported from U-Boot if
necessary.
Sascha
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prev parent reply other threads:[~2010-02-08 13:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-06 21:00 Krzysztof Halasa
2010-02-07 10:50 ` Marc Kleine-Budde
2010-02-07 18:44 ` Flash drivers, was: " Krzysztof Halasa
2010-02-08 10:06 ` Sascha Hauer
2010-02-11 22:29 ` Krzysztof Halasa
2010-02-08 13:40 ` Sascha Hauer [this message]
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