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SubjectRe: [RFC 5/6] dmaengine: xilinx_dma: Program interrupt delay timeout
On Mon, Apr 02, 2018 at 04:09:05PM +0530, Radhey Shyam Pandey wrote:
> Program IRQDelay for AXI DMA. The interrupt timeout mechanism causes
> the DMA engine to generate an interrupt after the delay time period
> has expired. It enables dmaengine to respond in real-time even though
> interrupt coalescing is configured.

again you are doing this only for axieth_connected, why is that?

>
> Signed-off-by: Radhey Shyam Pandey <radheys@xilinx.com>
> ---
> drivers/dma/xilinx/xilinx_dma.c | 16 ++++++++++++++--
> 1 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
> index 518465e..ab8f1b0 100644
> --- a/drivers/dma/xilinx/xilinx_dma.c
> +++ b/drivers/dma/xilinx/xilinx_dma.c
> @@ -161,8 +161,12 @@
> /* AXI DMA Specific Masks/Bit fields */
> #define XILINX_DMA_MAX_TRANS_LEN GENMASK(22, 0)
> #define XILINX_DMA_CR_COALESCE_MAX GENMASK(23, 16)
> +#define XILINX_DMA_CR_DELAY_MAX GENMASK(31, 24)
> #define XILINX_DMA_CR_CYCLIC_BD_EN_MASK BIT(4)
> #define XILINX_DMA_CR_COALESCE_SHIFT 16
> +#define XILINX_DMA_CR_DELAY_SHIFT 24
> +#define XILINX_DMA_CR_WAITBOUND_DFT 254
> +
> #define XILINX_DMA_BD_SOP BIT(27)
> #define XILINX_DMA_BD_EOP BIT(26)
> #define XILINX_DMA_COALESCE_MAX 255
> @@ -1294,6 +1298,12 @@ static void xilinx_dma_start_transfer(struct xilinx_dma_chan *chan)
> reg &= ~XILINX_DMA_CR_COALESCE_MAX;
> reg |= chan->desc_pendingcount <<
> XILINX_DMA_CR_COALESCE_SHIFT;
> +
> + if (chan->xdev->has_axieth_connected) {
> + reg &= ~XILINX_DMA_CR_DELAY_MAX;
> + reg |= XILINX_DMA_CR_WAITBOUND_DFT <<
> + XILINX_DMA_CR_DELAY_SHIFT;
> + }
> dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, reg);
> }
>
> @@ -1508,7 +1518,8 @@ static irqreturn_t xilinx_dma_irq_handler(int irq, void *data)
> }
> }
>
> - if (status & XILINX_DMA_DMASR_DLY_CNT_IRQ) {
> + if (!chan->xdev->has_axieth_connected && (status &
> + XILINX_DMA_DMASR_DLY_CNT_IRQ)) {
> /*
> * Device takes too long to do the transfer when user requires
> * responsiveness.
> @@ -1516,7 +1527,8 @@ static irqreturn_t xilinx_dma_irq_handler(int irq, void *data)
> dev_dbg(chan->dev, "Inter-packet latency too long\n");
> }
>
> - if (status & XILINX_DMA_DMASR_FRM_CNT_IRQ) {
> + if (status & (XILINX_DMA_DMASR_FRM_CNT_IRQ |
> + XILINX_DMA_DMASR_DLY_CNT_IRQ)) {
> spin_lock(&chan->lock);
> xilinx_dma_complete_descriptor(chan);
> chan->idle = true;
> --
> 1.7.1
>

--
~Vinod

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