Re: [PATCH] [OMAPZOOM] OMAP : DMA: Spurious interrupt fix

[Tony Lindgren <tony@atomide.com>]

* Shilimkar, Santosh <santosh.shilimkar@ti.com> [090109 14:52]:
> > -----Original Message-----
> > From: Tony Lindgren [mailto:tony@atomide.com] 
> > Sent: Friday, January 09, 2009 4:58 PM
> > To: Shilimkar, Santosh
> > Cc: Pandita, Vikram; linux-omap@vger.kernel.org
> > Subject: Re: [PATCH] [OMAPZOOM] OMAP : DMA: Spurious interrupt fix
> > 
> > * Shilimkar, Santosh <santosh.shilimkar@ti.com> [090109 12:51]:
> > > 
> > > Tony,
> > > Regarding your proposal of doing the no. of channel 
> > reservation during runtime has one problem. 
> > > 
> > > The whole idea was not to restrict users from using all 32 
> > channels and hence the config option. For OMAP secure chips, 
> > few security drivers which will execute in secure contex 
> > needs dedicated DMA channels and kernel dma library can't be 
> > used in that case. So in such cases, required DMA channels 
> > can be reserved using this config option. For GP devices all 
> > 32 channels can be used currently. 
> > > 
> > > If it can done in better way, please suggest.
> > 
> > Well how about passing the configuration for the DMA channels
> > from board-*.c file then?
> This is certainly a good option if the setting is fixed for a particular board type. With this how do we ensure user configurability. Lets say on a particular board, two users/customers wants to use separate configurations for DMA channels because of the needs what mentioned earlier. Then again we need some kind of comfit option.
>    Another clean way to achieve this is through 'bootargs'. But this might be too much of a design for this requirement.

Hmm, well how about starting with all of them, and allow
limiting the active DMA number via /sys? I guess we could
just set some of the DMA channels inactive that way.

Or maybe allow setting indvidual DMA channels inactive
via /sys?

> > > Time being if needed what best I can do is, to split this 
> > patch into two parts as mentioned earlier. This will avoid 
> > confusion of spurious interrupt issue and dam channel reservation
> > OK
> I will do this once I get some time for sure.

Great!

Tony