Hi, On 04/12/2016 10:33 PM, Sebastian Andrzej Siewior wrote: > On 04/11/2016 10:10 PM, Peter Hurley wrote: >> On 04/11/2016 11:31 AM, Sebastian Andrzej Siewior wrote: >>> On 04/11/2016 07:53 PM, Peter Hurley wrote: >>>> On 04/11/2016 01:18 AM, John Ogness wrote: >>>>> On 2016-04-05, Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote: >>>>>> On 03/31/2016 01:41 AM, John Ogness wrote: [...] >> *am335x* > > I am not sure if the limitations are based on the DMA engine or the > >> - requires write to tx fifo to trigger tx dma (ie. OMAP_DMA_TX_KICK >> workaround necessitating completely different tx dma completion handler) > > This one for instance I don't see on BeagleBoard xM / omap36xx and > DRA7x. Both (not affected) use SDMA instead EDMA. It would be > interesting to see if DRA7x is affected once it uses EDMA. > 8250 UART DMA works fine with EDMA as the DMA engine. As per my testing, am335x + EDMA, am437x + EDMA, dra7xx + EDMA and dra72x + EDMA require OMAP_DMA_TX_KICK quirk. However when using SDMA OMAP_DMA_TX_KICK is not needed (I tested on dra7xx platform). So, it can be concluded that when using EDMA with 8250 UART tx kick is needed. -- Regards Vignesh -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
