Re: usb and no bus_dma(9)

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

> > > > > Our usb driver demands bus_dma(9) without fail.  However, slhci(4)
> > > > > doesn't use DMA.  Moreover, some ports is not supporting bus_dma(9)
> > > > > now.
> > > > Isn't it easy to provide a bus_dma implementation that does not realy
> > > > do dma?
> > > > That would be far preferable to crippling lots of other code with MD 
> > > > hacks,
> > > > IMHO.
> > > 
> > > I think that it is strange to implement bus_dma(9) for port that doesn't
> > > use DMA.
> > 
> > For compromise, how about:
> >  - use "#if NUHCI > 0 || NOHCI > 0 || NEHCI > 0" (or so) in *.c sources
> 
> That's not as bad as the original #ifdef mmeye stuff, but still, ew...
> If your point is to avoid including some DMA code when usb is not included,

The point is "usb* at slhci?" is usb but it doesn't use DMA,
unlike uhci/ohci/ehci.

> can that be done with config attributes instead?
> i.e. in arch/mmeye/conf/files.mmeye do:
> 
> file common/bus_dma/bus_dmamem_common.c   usb

What does it solve??

> Perhaps you're focusing too much on the literal "dma" part of "bus_dma".
> The man page for bus_dma_alloc says it 'Allocates memory that is "DMA 
> safe"...'
> but if the hardward doesn't do DMA, it seems reasonable to declare that 
> any memory allocated with malloc() is "safe".

That's what Kiyohara's patch does, isn't it?
I'm suggesting to use #ifdef N?HCI instead of #ifdef mmeye.
---
Izumi Tsutsui