RE: [PATCH v8 2/2] omap hsmmc: adaptation of sdma descriptor autoloading feature

Madhusudhan
2010-05-07T16:59:46Z

> -----Original Message-----
> From: Shilimkar, Santosh [mailto:santosh.shilimkar@ti.com]
> Sent: Thursday, May 06, 2010 11:52 PM
> To: Chikkature Rajashekar, Madhusudhan; 'kishore kadiyala'
> Cc: S, Venkatraman; linux-omap@vger.kernel.org; linux-mmc@vger.kernel.org;
> linux-arm-kernel@lists.arm.linux.org.uk; 'Adrian Hunter'; Kadiyala,
> Kishore; 'Tony Lindgren'
> Subject: RE: [PATCH v8 2/2] omap hsmmc: adaptation of sdma descriptor
> autoloading feature
>
> > -----Original Message-----
> > From: Chikkature Rajashekar, Madhusudhan
> > Sent: Thursday, May 06, 2010 9:50 PM
> > To: Shilimkar, Santosh; 'kishore kadiyala'
> > Cc: S, Venkatraman; linux-omap@vger.kernel.org; linux-
> mmc@vger.kernel.org; linux-arm-
> > kernel@lists.arm.linux.org.uk; 'Adrian Hunter'; Kadiyala, Kishore; 'Tony
> Lindgren'
> > Subject: RE: [PATCH v8 2/2] omap hsmmc: adaptation of sdma descriptor
> autoloading feature
> >
> >
> >
> > > -----Original Message-----
> > > From: Shilimkar, Santosh [mailto:santosh.shilimkar@ti.com]
> > > Sent: Thursday, May 06, 2010 4:39 AM
> > > To: kishore kadiyala
> > > Cc: S, Venkatraman; linux-omap@vger.kernel.org; linux-
> mmc@vger.kernel.org;
> > > linux-arm-kernel@lists.arm.linux.org.uk; Chikkature Rajashekar,
> > > Madhusudhan; Adrian Hunter; Kadiyala, Kishore; Tony Lindgren
> > > Subject: RE: [PATCH v8 2/2] omap hsmmc: adaptation of sdma descriptor
> > > autoloading feature
> > >
> > > > -----Original Message-----
> > > > From: kishore kadiyala [mailto:kishorek.kadiyala@gmail.com]
> > > > Sent: Thursday, May 06, 2010 2:32 PM
> > > > To: Shilimkar, Santosh
> > > > Cc: S, Venkatraman; linux-omap@vger.kernel.org; linux-
> > > mmc@vger.kernel.org; linux-arm-
> > > > kernel@lists.arm.linux.org.uk; Chikkature Rajashekar, Madhusudhan;
> > > Adrian Hunter; Kadiyala, Kishore;
> > > > Tony Lindgren
> > > > Subject: Re: [PATCH v8 2/2] omap hsmmc: adaptation of sdma
> descriptor
> > > autoloading feature
> > > >
> > > > <<snip>>
> > > >
> > > > >> I am not clear about the method. The board files export the
> > > > >> omap_mmc_platform_data.
> > > > >> Does it imply that all board files have to change and export
> > > > >> the capability so that it can be queried ?
> > > > > No. You don't have to modify the board files. This would need
> > > > > change in devices.c which common for all omap boards.
> > > > >
> > > > > I don't have a strong opinion on this point but just put forth an
> > > > > alternate way to avoid such SOC specific check in drivers.
> > > > > You can take call on this
> > > >
> > > > Agree. How about adding a flag in hsmmc.h & omap_mmc_platform_data,
> > > > that would take care of SDMA & SDMA_DLAOD in the driver instead
> going
> > > > with SOC check .
> > >
> > > Good idea Kishore.
> > > Venkat,
> > > Can you do what kishore is suggesting.
> > >
> > omap_mmc_platform_data is MMC specific platform data. Why add a SDMA
> > specific feature capability into it? Even though you add it there, you
> will
> > still need to have a cpu check before that can be set in a common code.
> >
>
> CPU checks are allowed to be in the platform files. That is where such
> machine/SOC specific differentiation should be done and not in the device
> drivers.
> That way device drivers remains clean and portable.
>
> I want to stop this thread here since neither the patch author nor the
> file
> maintainer thinks that cpu checks in the device drivers is bad idea.
>
> Please decide within yourself and move on.
>

I am not saying that it is wrong. My point here is that adding this
particular flag into MMC platform data to differentiate a SDMA specific
feature which got introduced post certain SOC may not be needed. But you can
always post your comments on the list which will be looked at by a wider
audience and finally the right patch will go in.

> Regards,
> Santosh