[PATCH RFC 1/2] MUSB: CPPI 4.1 DMA driver (take 4)
felipe.balbi at nokia.com
Mon Nov 2 06:38:37 EST 2009
On Mon, Nov 02, 2009 at 12:24:00PM +0100, ext Gupta, Ajay Kumar wrote:
> > >
> > > > 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.
> Sounds good.
> So if we want to move CPPI4.1 DMA core to drivers/dma then it has to follow
> standard set of DMA APIs (right?), which I afraid, may not be done in current implementation.
yes, if it's not done right now, it has to be done.
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