> -----Original Message-----
> From: Marek Vasut <marex@xxxxxxx>
> Sent: Thursday, October 31, 2024 10:41 PM
> To: dmaengine@xxxxxxxxxxxxxxx
> Cc: Marek Vasut <marex@xxxxxxx>; Uwe Kleine-König <u.kleine-
> koenig@xxxxxxxxxxxx>; Simek, Michal <michal.simek@xxxxxxx>; Peter Korsgaard
> <peter@xxxxxxxxxxxxx>; Pandey, Radhey Shyam
> <radhey.shyam.pandey@xxxxxxx>; Vinod Koul <vkoul@xxxxxxxxxx>; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx
> Subject: [PATCH] dmaengine: xilinx_dma: Configure parking registers only if parking
> enabled
>
> The VDMA can work in two modes, parking or circular. Do not program the parking
> mode registers in case circular mode is used, it is useless.
>
> Signed-off-by: Marek Vasut <marex@xxxxxxx>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
Thanks!
> ---
> Cc: "Uwe Kleine-König" <u.kleine-koenig@xxxxxxxxxxxx>
> Cc: Michal Simek <michal.simek@xxxxxxx>
> Cc: Peter Korsgaard <peter@xxxxxxxxxxxxx>
> Cc: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
> Cc: Vinod Koul <vkoul@xxxxxxxxxx>
> Cc: dmaengine@xxxxxxxxxxxxxxx
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> ---
> drivers/dma/xilinx/xilinx_dma.c | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c index
> 48647c8a64a5b..87db381ff1286 100644
> --- a/drivers/dma/xilinx/xilinx_dma.c
> +++ b/drivers/dma/xilinx/xilinx_dma.c
> @@ -1404,16 +1404,18 @@ static void xilinx_vdma_start_transfer(struct
> xilinx_dma_chan *chan)
>
> dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, reg);
>
> - j = chan->desc_submitcount;
> - reg = dma_read(chan, XILINX_DMA_REG_PARK_PTR);
> - if (chan->direction == DMA_MEM_TO_DEV) {
> - reg &= ~XILINX_DMA_PARK_PTR_RD_REF_MASK;
> - reg |= j << XILINX_DMA_PARK_PTR_RD_REF_SHIFT;
> - } else {
> - reg &= ~XILINX_DMA_PARK_PTR_WR_REF_MASK;
> - reg |= j << XILINX_DMA_PARK_PTR_WR_REF_SHIFT;
> + if (config->park) {
> + j = chan->desc_submitcount;
> + reg = dma_read(chan, XILINX_DMA_REG_PARK_PTR);
> + if (chan->direction == DMA_MEM_TO_DEV) {
> + reg &= ~XILINX_DMA_PARK_PTR_RD_REF_MASK;
> + reg |= j << XILINX_DMA_PARK_PTR_RD_REF_SHIFT;
> + } else {
> + reg &= ~XILINX_DMA_PARK_PTR_WR_REF_MASK;
> + reg |= j << XILINX_DMA_PARK_PTR_WR_REF_SHIFT;
> + }
> + dma_write(chan, XILINX_DMA_REG_PARK_PTR, reg);
> }
> - dma_write(chan, XILINX_DMA_REG_PARK_PTR, reg);
>
> /* Start the hardware */
> xilinx_dma_start(chan);
> --
> 2.45.2
