Re: Block request processing for MMC/SD over SPI bus

Hans Eklund
2006-08-08T15:05:51Z

On Tuesday 01 August 2006 10:42, Russell King wrote:
> On Tue, Aug 01, 2006 at 10:37:27AM +0200, Hans Eklund wrote:
> > The driver is also independent of any previous MMC related work at this
> > point since MMC over SPI mode differs somewhat from the MMC mode.
>
> You may be interested to know that David Brownell (I believe) has a
> driver which connects the SPI framework to the MMC subsystem, allowing
> the MMC subsystem to talk to cards in SPI mode.
>
> Maybe David can help, or point you in the direction of someone who
> can in the case that I'm misremembering.

Hi again Russel.

I have been talking to David Brownell and some other developers connected to
ADI(Analgo devices) about the SPI to MMC subsystem driver. That idea will
probably be implemented in a later phase. For now, i will complete my MMC/SD
driver that connects to the common SPI framwork and will remain independent
of the MMC subsystem so it can be used on uClinux platforms(ADI Blackfin
based to a start) sooner.

For that reason am i talking to you. By a mere coincidence i saw that you are
the author of /drivers/mmc/mmc_queue.c driver and hence i guess you have some
knowledge regarding request processing that may be useful to the project.

I would say my driver need some attention to that particular part. And i would
appreciate any help. As of now, it is a very naive way of walking the request
queue(a la LDD handbook) and it need to support some basic error handling.

I have posted a copy of the make_request implementation here(~150 lines):

http://hasse.yohoo.nu/strat.txt

It is quite extesively commented, and some important questions at the end.
Hope you can have look at it and maybe give me a guideline.

If you dont have the time, i understand, maybe you know someone who has?

best regards

Hans Eklund,
Rubico AB, www.rubico.se
Sweden.