[U-Boot-Users] Atmel DataFlash hooks.

Haavard Skinnemoen hskinnemoen at gmail.com
Mon Jan 29 22:06:12 CET 2007

On 1/29/07, Wolfgang Denk <wd at denx.de> wrote:
> In message <528646bc0701281850n4b4fa2b1x7022b4daf9bfe89a at mail.gmail.com> you wrote:

> > > IMHO we should provide a user inteface which is powerful, yet easy to
> > use - this requires it must be intuitive to the end user. For most  f
> > > them,  (NOR) flash *is* memory, while and IDE or USB disk and even an
> > > EEPROM is not.
> >
> > Right; so what do we do with MMC and DataFlash?
> So far I hear only discussion from developers.
> Are there any users of Dataflah and MCC here? What  is  your  opinion
> about the current user interface, abd about the suggested changes?

I'm not sure if I understand. U-boot pretends mmc and DataFlash are
memory mapped? That sounds completely insane, especially for MMC. What
happens if you insert an 8GB SD card on a 32-bit host?

I haven't actually used DataFlash on any avr32 boards yet, but I have
written an MMC driver for it and I didn't even know it could be
accessed as a memory-mapped device. In fact, I can't even understand
why anyone would want that -- the main usage of an MMC or SD card is
to put a filesystem (usually FAT, but you can use pretty much
anything) on it and use it for storage.

I guess DataFlash makes slightly more sense to access this way, but I
still think the interface is totally unintuitive.

So, even though I'm technically more of a developer than a user,
consider this a vote in favour of ripping the stuff out. Unless of
course lots of users depend on stuff working this way. I highly doubt
it since it doesn't even work properly (yes, the MMC stuff too; the
mmc2info function on pxa is a total hack which only works for 32MB


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