Hi Pierre,
My card driver needed to set the R/W E4MI bit in the Card Capability
register (0x08) in CCCR (function 0). Perhaps it is unnecessary ?
BTW. It is easy to for the card driver to access function 0 registers by
doing the following...
...
int old_num = func->num; /* note the current function number */
/* force access to function 0 area */
func->num = 0;
/* enable the e4mi in the card capability register */
x = sdio_readb(func, 0x000008, &ret);
if ( ret == 0 ) {
x |= 0x20;
sdio_writeb(func, x, 0x000008, &ret);
}
/* restore to original function number */
func->num = old_num;
...
Regards,
Dean.
On Tue, 2007-11-20 at 11:51 +0100, Pierre Ossman wrote:
> On Tue, 20 Nov 2007 10:28:53 +0000
> Dean Jenkins <[EMAIL PROTECTED]> wrote:
>
> > Hi Pierre,
> >
> > I've managed to find your E-mail address in the Linux kernel mailing
> > list. I hope it is OK to directly E-mail you ?
> >
>
> You should also find my address in the MAINTAINERS file, which is where you
> should look for contact info. But yes, you can contact me directly. I prefer
> that you also add a relevant mailing list though.
>
> > I work for MontaVista Software in the UK. I guess you know that
> > MontaVista are using the MMC/SDIO sub-system in their latest Mobilinux
> > 5.0 product ? It is using a 2.6.21 kernel.
> >
> > Yesterday, I sent an E-mail to you (attached) to the Linux kernel
> > mailing list. Do you have any comments to make ?
> >
>
> Didn't notice it. I'll have a look.
>
> > Do you have any bug reporting facility for the MMC/SDIO sub-system ? I
> > would like to report some SDIO API limitations for the SDIO card drivers
> > that I needed to workaround. For example, my SDIO driver needs to modify
> > the contents of the Card Capability register in function 0 to enable
> > block-mode support but the card driver has been restricted to only be
> > able to use function 1. There are other registers as well that the card
> > driver needs access to.
> >
>
> That is by design (as you probably can tell). Letting function drivers touch
> card global stuff under the feet of the SDIO core is a big layering violation
> and bound to screw things up eventually.
>
> Could you explain more in detail what it is you need to fiddle with in
> function 0 and why?
>
> Rgds
--
Dean Jenkins
Embedded Software Engineer
MontaVista Software (UK)
Professional Services Division
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