Re: [Fwd: MMC sub-system: SDIO block-mode with increment address issue]
On Tue, 20 Nov 2007 14:52:37 + Dean Jenkins <[EMAIL PROTECTED]> wrote: > 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 ? > That bit is pointless given the current design of the MMC layer, so it shouldn't be necessary. > BTW. It is easy to for the card driver to access function 0 registers by > doing the following... > Of course. Any driver can do whatever it pleases since it is in kernel space. But you won't make any friends if you keep trying to bypass every system in the kernel. ;) (Not to mention you'll have a lot more work on your hands.) Rgds -- -- Pierre Ossman Linux kernel, MMC maintainerhttp://www.kernel.org PulseAudio, core developer http://pulseaudio.org rdesktop, core developer http://www.rdesktop.org - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [Fwd: MMC sub-system: SDIO block-mode with increment address issue]
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, 0x08, );
if ( ret == 0 ) {
x |= 0x20;
sdio_writeb(func, x, 0x08, );
}
/* 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 +
> 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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Please read the FAQ at http://www.tux.org/lkml/
Re: [Fwd: MMC sub-system: SDIO block-mode with increment address issue]
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, 0x08, ret);
if ( ret == 0 ) {
x |= 0x20;
sdio_writeb(func, x, 0x08, 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 +
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
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [Fwd: MMC sub-system: SDIO block-mode with increment address issue]
On Tue, 20 Nov 2007 14:52:37 + Dean Jenkins [EMAIL PROTECTED] wrote: 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 ? That bit is pointless given the current design of the MMC layer, so it shouldn't be necessary. BTW. It is easy to for the card driver to access function 0 registers by doing the following... Of course. Any driver can do whatever it pleases since it is in kernel space. But you won't make any friends if you keep trying to bypass every system in the kernel. ;) (Not to mention you'll have a lot more work on your hands.) Rgds -- -- Pierre Ossman Linux kernel, MMC maintainerhttp://www.kernel.org PulseAudio, core developer http://pulseaudio.org rdesktop, core developer http://www.rdesktop.org - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
