Hello. On 02-02-2013 22:07, Matt Porter wrote:
Move mach-davinci/dma.c to common/edma.c so it can be used by OMAP (specifically AM33xx) as well.
I think this should rather go to drivers/dma/?
No, this is the private EDMA API. It's the analogous thing to the private OMAP dma API that is in plat-omap/dma.c. The actual dmaengine driver is in drivers/dma/edma.c as a wrapper around this...same way OMAP DMA engine conversion is being done.
Keeps me wondering why we couldn't have the same with CPPI 4.1 when I proposed that, instead of waiting indefinitely for TI to convert it to drivers/dma/ directly. We could have working MUSB DMA on OMAP-L1x/Sitara all this time... Sigh.
That is a shame. Yeah, I've pointed out that I was doing this exactly the same way as was acceptable for the OMAP DMA conversion since it was in RFC. The reasons are sound since in both cases, we have many drivers to convert that need to continue using the private DMA APIs.
In case of CPPI 4.1, we'd only have to convert MUSB DMA driver. Other in-tree CPPI 4.1 having SoCs don't use it for anything but MUSB -- it even is sub-block of their MUSB device, AFAIK (I maybe wrong about Sitaras -- I don't know them well).
Well, it's pretty clear to me now that there's good reason for it not landing in arch/arm/ so the obvious path is to do the dmaengine conversion and put it in drivers/dma/ if it's really a generic dma engine. I'm not sure why you express concern over the dma engine api not fitting with CPPI 4.1?
It's not a DMA controller only, it's 3 distinct devices, with the DMA controller being one among them and using another one, the queue manager, as some sort of proxy. The third device doesn't exist on OMAP-L1x SoCs -- it's the buffer manager.
If it doesn't work, work with Vinod to fix the api. It's expected, I'm working on dmaengine API changes right now to deal with a limitation of EDMA that needs to be abstracted.
Sorry, now it's TI's task. I no longer have time to work on this (my internal project to push OMAP-L1x support upstream has expired at Sep 2010) and my future in MV is very uncertain at this moment. Most probably I'll leave it (or be forced to leave).
As pointed out, edma.c is already here in arch/arm/, so moving it doesn't add something new. It does let us regression test all platforms that use it (both Davinci and AM33xx) as I go through the conversion process.
Could have been the same with CPPI 4.1 in theory if it was added to mach-davinci/ back in 2009... we'd then only have to move it. EDMA code is much older of course, so it's probably more justified.
-Matt
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