[PATCH RFC 1/2] MUSB: CPPI 4.1 DMA driver (take 4)

[Felipe Balbi]

On Mon, Nov 02, 2009 at 11:57:59AM +0100, ext Gupta, Ajay Kumar wrote:
> > On Mon, Nov 02, 2009 at 09:51:13AM +0530, Gupta, Ajay Kumar wrote:
> > > Is there any updated patch on cppi4.1 core also?
> > 
> > Is there _any_ cppi4.1 core patch anywhere?  Not according to google.
> 
> Russell,
> 
> Here is the latest version of cppi4.1 core.
> http://patchwork.kernel.org/patch/46698/
> 
>  
> > > Another option is to create arch/arm/ti-common to place all TI
> > platform's
> > > common software, such as CPPI4.1 used both in DA8xx and AM3517.
> > 
> > No thanks.  I really don't see why we should allow TI to have yet more
> > directories scattered throughout the tree that are out of place with
> > existing conventions.
> > 
> > And what is this CPPI thing anyway?
> > 
> > http://acronyms.thefreedictionary.com/CPPI
> > 
> > "Communications Port Programming Interface" seems to be about the best
> > applicable one from that list!
> 
> Yes, this is the correct one.
> 
> > If it's a USB DMA device (from the patches I can find, that seems to be
> > the case) then why can't it live in drivers/usb or drivers/dma ?
> 
> CPPI4.1 DMA engine can be used either by USB or by Ethernet interface though
> currently only USB is using it but in future even Ethernet devices may use it.
> 
> Infact, there is a TI platform (not in mainline), where both USB and Ethernet interface is using CPPI4.1 DMA.

you might want to provide support for it via drivers/dma and for the
musb stuff, you just add the wrappers musb uses. See how tusb6010_omap.c
uses OMAP's system dma which is also used by any other driver which
requests a dma channel.

-- 
balbi