On 06/09/16 14:04, Jon Hunter wrote: > > On 06/09/16 13:03, Dmitry Osipenko wrote: >> On 06.09.2016 14:33, Jon Hunter wrote: >>> >>> On 03/09/16 01:32, Nicolin Chen wrote: >>>> This series of patches add memcpy support for tegra210 ADMA engine. >>> >>> Thanks. Any reason you choose this DMA and not the APB DMA? The APB DMA >>> is more of a generic DMA and so for memcpy it would seem to be a good >>> choice and it is available on all Tegras not just Tegra210. >>> >> >> Just a small clarification: >> >> If I'm not mistaken, APB DMA is mem-to-device, while AHB DMA is mem-to-mem. So, >> you probably meant AHB and not the APB. > > Description from the Tegra TRM: > > "The APB DMA Controller is placed between the AHB Bus and the APB Bus > and is a master on both buses. > > The APB DMA Controller is used for block data transfers from a source > location to the destination location. The source may be > DRAM or IRAM, and the destination location could be devices placed on > APB Bus; or vice versa." Sorry this appears to be a completely worthless response :-( I had made the assumption that if the DMA can transfer from APB-to-AHB and AHB-to-APB, it could also do AHB to AHB. However, now I look closely at the registers I see that it cannot and therefore, cannot support memcpy at all! Ok, so ignore my comment here, as it appears only the ADMA can support memcpy. Weird. Jon -- nvpublic -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
