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

Gupta, Ajay Kumar ajay.gupta at ti.com
Tue Dec 29 03:43:49 EST 2009

> Hello.
> Russell King - ARM Linux wrote:
>>>>Is there any updated patch on cppi4.1 core also?
>>>Is there _any_ cppi4.1 core patch anywhere?  Not according to google.
>>Here is the latest ersion of cppi4.1 core.

>> [...]

>>>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.

> drivers/dma does seem to be the right place for this.

>    Russell, it makes me wonder why drivers/dma/ seemed the right place to 
> you, just because of the name? :-)
>    After spending some time on studying the infrastructure there I came to 
> conclusion that this is not the right place because all the controllers 
> supported there have features like memory-to-memory transfers or even RAID 
> function offloading -- which CPPI 4.1 totally lacks (it's there purely to 
> serve the peripherals).
>    Adding drivers/dma/ people to this discussion in hopes they can correct 
> me (or support me :-)...

As this discussion is taking time which is affecting the further
development and bug fixes on CPPI4.1. 

So can we move CPPI4.1 files to drivers/usb/musb for time being and submit
a replacement patch whenever we all agree on the location of CPPI4.1
related files.


> WBR, Sergei
> --

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