Messages in this thread | | | Date | Fri, 13 Jan 2012 22:12:07 +0200 | From | Felipe Balbi <> | Subject | Re: RFC: usb: musb: Adding CPPI4.1 DMA driver under drivers/dma |
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On Fri, Jan 13, 2012 at 10:09:32AM -0800, Greg KH wrote: > On Fri, Jan 13, 2012 at 10:40:50AM +0000, Gupta, Ajay Kumar wrote: > > Hi, > > > > CPPI4.1 (Communication Port Programming Interface) is a TI specific DMA > > controller used in multiple TI platform such as AM33x, DA8x, AM35x, TI81x. > > The DMA engine is mainly used by musb controller on above platform. > > > > Earlier version of the driver was submitted by Sergei Shtylyov at [1] but > > was not merged due to disagreement on the location of driver in kernel. > > Refer the discussions at [1] for more details. > > > > [1] http://marc.info/?l=linux-usb&m=125087318308323 > > > > The new implementation of the CPPI4.1 DMA slave driver will be in the > > drivers/dma folder, complying to dmaengine framework. > > It would involve changes in existing musb driver also for which current > > plan is to maintain the compatibility of non-CPPI4.1 DMA in musb driver. > > > > The task is planned to be spitted into below subtasks. > > > > (1) Post RFC on the API details, changes envisaged in musb driver and other > > challenges > > > > (2) Implement and post RFC for the CPPI4.1 DMA driver and changes needed in > > musb driver. > > > > Let me know if you have any thoughts/comments on this. > > First off, don't highjack threads (you responded to a linux-usb thread > here, get a better email client please.) > > Second, that sounds fine, please post patches.
I'm with Greg here, please post patches.
What I suggest is:
- first create a dma-engine.c file on drivers/usb/musb which will simply translate dmaengine into the MUSB-specific API. this will allow us to slowly convert other platforms without breaking the legacy stuff.
- Then move CPPI to drivers/dma
- Test it all out ;-)
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