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Subject[PATCH -next 3/8] dmaengine: xilinx_dma: Introduce xilinx_dma_get_residue
Date
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;
+
+ /**
+ * 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;
+
+ 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
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