On 29/06/2021 06:59, Tamseel Shams wrote: > When DMA is used for TX and RX by serial driver, it should > pass the DMA device pointer to DMA API instead of UART device > pointer. DMA device should be used for DMA API because only > the DMA device is aware of how the device connects to the memory. > There might be an extra level of address translation due to a > SMMU attached to the DMA device. When serial device is used for > DMA API, the DMA API will have no clue of the SMMU attached to > the DMA device. > > This patch is necessary to fix the SMMU page faults > which is observed when a DMA(with SMMU enabled) is attached > to UART for transfer. > > Signed-off-by: Tamseel Shams <m.shams@xxxxxxxxxxx> > Signed-off-by: Ajay Kumar <ajaykumar.rs@xxxxxxxxxxx> > --- > Changes since v1: > 1. Rebased the patch on "tty-next" branch of TTY driver tree > > Changes since v2: > 1. Updated the commit message. > 2. Changed the comment description > > Changes since v3: > 1. Removed the null pointer check for "dma", "dma->tx_chan" and > "dma->rx_chan" and instead sending DMA device pointer while calling > DMA API. > > Changes since v4: > 1. Fixed the alignments of arguments. > > drivers/tty/serial/samsung_tty.c | 46 +++++++++++++++++--------------- > 1 file changed, 25 insertions(+), 21 deletions(-) > Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxx> Best regards, Krzysztof
