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SubjectRe: [PATCH -next 3/8] dmaengine: xilinx_dma: Introduce xilinx_dma_get_residue
On 05-09-19, 22:06, Radhey Shyam Pandey wrote:
> From: Nicholas Graumann <nick.graumann@gmail.com>
>
> Introduce a function that can calculate residues for IPs that support it:
> AXI DMA and CDMA.
>
> Signed-off-by: Nicholas Graumann <nick.graumann@gmail.com>
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
> ---
> drivers/dma/xilinx/xilinx_dma.c | 75 ++++++++++++++++++++++++++++++-----------
> 1 file changed, 56 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
> index 9909bfb..4094adb 100644
> --- a/drivers/dma/xilinx/xilinx_dma.c
> +++ b/drivers/dma/xilinx/xilinx_dma.c
> @@ -787,6 +787,51 @@ static void xilinx_dma_free_chan_resources(struct dma_chan *dchan)
> }
>
> /**
> + * xilinx_dma_get_residue - Compute residue for a given descriptor
> + * @chan: Driver specific dma channel
> + * @desc: dma transaction descriptor
> + *
> + * Return: The number of residue bytes for the descriptor.
> + */
> +static u32 xilinx_dma_get_residue(struct xilinx_dma_chan *chan,
> + struct xilinx_dma_tx_descriptor *desc)
> +{
> + struct xilinx_cdma_tx_segment *cdma_seg;
> + struct xilinx_axidma_tx_segment *axidma_seg;
> + struct xilinx_cdma_desc_hw *cdma_hw;
> + struct xilinx_axidma_desc_hw *axidma_hw;
> + struct list_head *entry;
> + u32 residue = 0;
> +
> + /**

it should be:
/*
* comment...

> + * VDMA and simple mode do not support residue reporting, so the
> + * residue field will always be 0.
> + */
> + if (chan->xdev->dma_config->dmatype == XDMA_TYPE_VDMA || !chan->has_sg)
> + return residue;

why not check this in status callback?

> +
> + list_for_each(entry, &desc->segments) {
> + if (chan->xdev->dma_config->dmatype == XDMA_TYPE_CDMA) {
> + cdma_seg = list_entry(entry,
> + struct xilinx_cdma_tx_segment,
> + node);
> + cdma_hw = &cdma_seg->hw;
> + residue += (cdma_hw->control - cdma_hw->status) &
> + chan->xdev->max_buffer_len;
> + } else {
> + axidma_seg = list_entry(entry,
> + struct xilinx_axidma_tx_segment,
> + node);
> + axidma_hw = &axidma_seg->hw;
> + residue += (axidma_hw->control - axidma_hw->status) &
> + chan->xdev->max_buffer_len;
> + }
> + }
> +
> + return residue;
> +}
> +
> +/**
> * xilinx_dma_chan_handle_cyclic - Cyclic dma callback
> * @chan: Driver specific dma channel
> * @desc: dma transaction descriptor
> @@ -995,33 +1040,22 @@ static enum dma_status xilinx_dma_tx_status(struct dma_chan *dchan,
> {
> struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
> struct xilinx_dma_tx_descriptor *desc;
> - struct xilinx_axidma_tx_segment *segment;
> - struct xilinx_axidma_desc_hw *hw;
> enum dma_status ret;
> unsigned long flags;
> - u32 residue = 0;
>
> ret = dma_cookie_status(dchan, cookie, txstate);
> if (ret == DMA_COMPLETE || !txstate)
> return ret;
>
> - if (chan->xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) {
> - spin_lock_irqsave(&chan->lock, flags);
> + spin_lock_irqsave(&chan->lock, flags);
>
> - desc = list_last_entry(&chan->active_list,
> - struct xilinx_dma_tx_descriptor, node);
> - if (chan->has_sg) {
> - list_for_each_entry(segment, &desc->segments, node) {
> - hw = &segment->hw;
> - residue += (hw->control - hw->status) &
> - chan->xdev->max_buffer_len;
> - }
> - }
> - spin_unlock_irqrestore(&chan->lock, flags);
> + desc = list_last_entry(&chan->active_list,
> + struct xilinx_dma_tx_descriptor, node);
> + chan->residue = xilinx_dma_get_residue(chan, desc);
>
> - chan->residue = residue;
> - dma_set_residue(txstate, chan->residue);
> - }
> + spin_unlock_irqrestore(&chan->lock, flags);
> +
> + dma_set_residue(txstate, chan->residue);
>
> return ret;
> }
> @@ -2701,12 +2735,15 @@ static int xilinx_dma_probe(struct platform_device *pdev)
> xilinx_dma_prep_dma_cyclic;
> xdev->common.device_prep_interleaved_dma =
> xilinx_dma_prep_interleaved;
> - /* Residue calculation is supported by only AXI DMA */
> + /* Residue calculation is supported by only AXI DMA and CDMA */
> xdev->common.residue_granularity =
> DMA_RESIDUE_GRANULARITY_SEGMENT;
> } else if (xdev->dma_config->dmatype == XDMA_TYPE_CDMA) {
> dma_cap_set(DMA_MEMCPY, xdev->common.cap_mask);
> xdev->common.device_prep_dma_memcpy = xilinx_cdma_prep_memcpy;
> + /* Residue calculation is supported by only AXI DMA and CDMA */
> + xdev->common.residue_granularity =
> + DMA_RESIDUE_GRANULARITY_SEGMENT;
> } else {
> xdev->common.device_prep_interleaved_dma =
> xilinx_vdma_dma_prep_interleaved;
> --
> 2.7.4

--
~Vinod

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