Re: RFC: usb: musb: Changes proposed for adding CPPI4.1 DMA

[Sergei Shtylyov]

Hello.

On 01/25/2012 06:22 PM, Gupta, Ajay Kumar wrote:

> As a next step to dma-engine based cppi4.1 driver implementation
> this RFC has the overview of changes in the musb driver.
> RFC on CPPI slave driver changes will follow next.

> Overview of changes in the musb driver
> ======================================

> 1)Add a dma-engine.c file in the drivers/usb/musb folder
> 2)This file will host the current musb dma APIs and translates them to
>    dmaengine APIs.
> 3)This will help to keep the changes in drivers/usb/musb/musb* files
>    minimal and also to retain compatibility other DMA (Mentor etc.)
>    drivers which are yet to be moved to drivers/dma
> 4)drivers/usb/musb/dma-engine.c, will wrap the dmaengine APIs to
>    make existing musb APIs compatible.
> 5)drivers/usb/musb/dma-engine.c file will implement the filter
>    functions and also implement .dma_controller_create (allocates
>    &  provides "dma_controller" object) and .dma_controller_delete
> 6)CPPI4.1 DMA specific queue and buffer management will be internal
>    to slave CPPI DMA driver implementation.

   You mean drivers/dma/ driver? I think you are forgotting that CPPI 4.1 MUSB 
has some registers controlling DMA/interrupts beside those of CPPI 4.1 
controller and MUSB core itself. How do they fit in your scheme?

WBR, Sergei
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