This series is the preliminary conversion of OMAPs private DMA API to DMAengine. It focuses on the OMAP HSMMC driver, as I believe that is the only DMA-capable driver which is used on the platforms I have available (3430LDP and 4430SDP). For the OMAP DMAengine driver, there's a few short-comings: 1. pause/resume support is not implemented; it's not clear whether the OMAP hardware is capable of supporting this sanely. 2. status function does not return DMA residue. 3. DMAengine holds on to physical DMA channels while the driver maintains a reference to the virtual DMA engine channel. This is not an issue with drivers; drivers should be able to hold a DMA channel for their lifetime. DMAengine code could be improved to dynamically allocate physical channels, but this should happen when more drivers have been converted. I took the approach with omap_hsmmc to add DMAengine support to the driver along side the existing DMA support, so that I had a stage where I could switch between the two implementations for comparisons - and also to allow me to run with read using DMAengine support, and write using the private API. This allowed a progressive switch over to using DMAengine, and allowed debugging without destroying the contents of the MMC card. A point about DMAengine and DMA API for anyone who contemplates converting other drivers: the struct device to be used for mapping/unmapping/coherent memory is the DMAengine's device structure (channel->device->dev) not the peripheral (eg, MMC) device structure. It's the DMAengine which is performing the DMA to memory, not the peripheral device. The peripheral device is merely receiving the data from the DMAengine, and does not care where that data has come from. So, dma masks for peripheral devices are meaningless (and wrong.) -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
