Vinod, On 27/01/2020 15.21, Peter Ujfalusi wrote: > Hi Vinod, > > Based on customer reports we have identified two issues with the UDMA driver: > > TX completion (1st patch): > The scheduled work based workaround for checking for completion worked well for > UART, but it had significant impact on SPI performance. > The underlying issue is coming from the fact that we have split data movement > architecture. > In order to know that the transfer is really done we need to check the remote > end's (PDMA) byte counter. > > RX channel teardown with stale data in PDMA (2nd patch): > If we try to stop the RX DMA channel (teardown) then PDMA is trying to flush the > data is might received from a peripheral, but if UDMA does not have a packet to > use for this draining than it is going to push back on the PDMA and the flush > will never completes. > The workaround is to use a dummy descriptor for flush purposes when the channel > is terminated and we did not have active transfer (no descriptor for UDMA). > This allows UDMA to drain the data and the teardown can complete. > > The last two patch is to use common code to set up the TR parameters for > slave_sg, cyclic and memcpy. The setup code is the same as we used for memcpy > with the change we can handle 4.2GB sg elements and periods in case of cyclic. > It is also nice that we have single function to do the configuration. I have marked these patches as for-next as 5.5 was not released yet. Would it be possible to have these as fixes for 5.6? Thanks, - Péter > > Regards, > Peter > --- > Peter Ujfalusi (3): > dmaengine: ti: k3-udma: Workaround for RX teardown with stale data in > peer > dmaengine: ti: k3-udma: Move the TR counter calculation to helper > function > dmaengine: ti: k3-udma: Use the TR counter helper for slave_sg and > cyclic > > Vignesh Raghavendra (1): > dmaengine: ti: k3-udma: Use ktime/usleep_range based TX completion > check > > drivers/dma/ti/k3-udma.c | 452 +++++++++++++++++++++++++++++---------- > 1 file changed, 343 insertions(+), 109 deletions(-) > Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
