Re: [Ksummit-discuss] [CORE TOPIC] (group) maintainership models

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Peter,

On Tuesday 02 Aug 2016 09:48:53 Peter Ujfalusi wrote:
> On 08/02/16 07:46, Vinod Koul wrote:
> > On Mon, Aug 01, 2016 at 04:10:29PM +0200, Arnd Bergmann wrote:
> >> On Monday, August 1, 2016 10:36:01 AM CEST Laurent Pinchart wrote:
> >>> On Monday 01 Aug 2016 08:56:30 Arnd Bergmann wrote:
> >>>> On Sunday, July 31, 2016 11:27:53 PM CEST Vinod Koul wrote:
> >>>>> On Thu, Jul 28, 2016 at 10:44:23AM +0200, Arnd Bergmann wrote:
> >>>>>> config FOO
> >>>>>> 
> >>>>>>       bool "foo driver" if COMPILE_TEST && !ARCH_FOO
> >>>>>>       default ARCH_FOO
> >>>>>>       depends on GPIOLIB && I2C && OF && WHATEVER
> >>>>>> 
> >>>>>> This becomes a silent always-on symbol if the platform is used,
> >>>>>> and user-selectable on every other platform with COMPILE_TEST.
> >>>>> 
> >>>>> Yeah this seems a bit more better. I am perhaps thinking to add top
> >>>>> level arch dependency if required. I will try this out on DMAengine to
> >>>>> start with and ease my build tests
> >>>> 
> >>>> Sounds good. Let me know if you end up having to add a 'depends on ARM'
> >>>> dependency anywhere, as that might indicate that we are doing something
> >>>> different on ARM that should be done in a more generic way.
> >>> 
> >>> OMAP DMA comes to mind, we still depend on the implementation provided
> >>> by arch/arm/plat-omap/dma.c.
> >> 
> >> That's a dependency on MACH_OMAP instead of ARM though, which is a bit
> >> different.
> >> 
> >> (Getting offtopic and) speaking of this one, is anyone working
> >> on converting the last four or five drivers to the dmaengine framework?
> > 
> > Rather lets' move this conversation to dmaengine list?
> > 
> >> drivers/media/platform/omap/omap_vout_vrfb.c
> 
> Needs the interleaved transfer type support in omap-dma. Now it is in -next.

Thank you for your work on this. When you'll have patches for 
omap_vout_vrfb.c, please let me know and I'll test them.

> >> drivers/mtd/onenand/omap2.c
> 
> Using memcpy, I have sent the patches:
> https://patchwork.kernel.org/patch/7842891/
> https://patchwork.kernel.org/patch/7851881/
> 
> but I need to revisit. I think the 'fix' will be to drop the DMA support
> from it.
> >> drivers/usb/gadget/udc/omap_udc.c
> >> drivers/usb/musb/tusb6010_omap.c
> 
> They are mostly slave implementations, but. As I recall they do some really
> interesting non symmetric setup for the TX/RX DMA which I still need to
> figure out. And I'm looking for HW to check for regression...
> 
> >> (and a bit of drivers/video/fbdev/omap/omapfb_main.c)
> 
> Hrm, that is OMAP1. Looks like highly coupled with mach-omap1/lcd_dma.c.
> This is going to be a bit complicated IMHO.
> 
> > Peter?
> > 
> >> I guess we could improve build coverage by moving
> >> arch/arm/plat-omap/dma.c into drivers/dma/omap-dma.c, but that
> >> has the disadvantage of exposing a nonstandard interface from
> >> somewhere inside of the dmaengine subsystem.
> > 
> > yeah that won't be nice. I think we should get these removed... We have
> > omap as well as edma driver in dmaengine.
> 
> I'm not going to move the legacy API under dmaengine, it makes no sense.
> 
> My plan is to do what I did with the eDMA driver stack:
> - convert drivers using the legacy API to dmaengine
> - 'merge' the code from plat-omap to the dmaengine driver
>   - while doing this the legacy API will vanish along with the
> plat-omap/dma.c
> 
> As with the eDMA, the sDMA stack will need some cleanup, but the good thing
> is that the dmaengine driver have minimal dependency on the legacy
> plat-omap/dma.c API.

-- 
Regards,

Laurent Pinchart