Hi, > On 31-01-2012 8:41, 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? > > > yes. > > >> 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? > > > We have been discussing on how to handle these in slave driver and > > These certainly cannot be handled in the slave driver because the > registers are different for every controller implementation and, the > main thing, they don't belong to CPPI 4.1 as such. Felipe suggested to use device tree for differences in register maps among different platforms. I do see issues in reading wrapper interrupt status register and then calling musb_interrupt() [defined inside musb_core.c] from slave driver. > > > would post our proposal in RFC for slave driver design. Do you have > > any proposal? > > I think this will need hooks from dma-engine.c to the glue layers. I > was going to implement such in my version of MUSB CPPI 4.1 driver (in order > to also support AM35x) but lacked time. That would mean a change in current drivers/dma API. Ajay > > > Regards, > > Ajay > > WBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
