This patch removes a bit of duplicated code by introducing a new
function that implements calculations for DMA copy size, and
prepares for changes to the copy size calculation that will
happen in following patches.
Suggested-by: Vinod Koul <vk...@kernel.org>
Signed-off-by: Andrea Merello <andrea.mere...@gmail.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pan...@xilinx.com>
---
Changes in v4:
- introduce this patch in the patch series
Changes in v5:
None
Changes in v6:
- 2/7 was basically redoing what done here. Anticipate
here the introduction of a local temporary variable
so that 2/7 just add stuff
- add dma chan ptr argument to xilinx_calc_cma_copysize()
to prepare for 2/7
- introduce max_buffer_len variable in advance, to prepare
for 4/7
- reword for above changes
---
drivers/dma/xilinx/xilinx_dma.c | 39 ++++++++++++++++++++++++++-------
1 file changed, 31 insertions(+), 8 deletions(-)
diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index c12442312595..2c1db500284f 100644
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c
@@ -423,6 +423,7 @@ struct xilinx_dma_config {
* @rxs_clk: DMA s2mm stream clock
* @nr_channels: Number of channels DMA device supports
* @chan_id: DMA channel identifier
+ * @max_buffer_len: Max buffer length
*/
struct xilinx_dma_device {
void __iomem *regs;
@@ -442,6 +443,7 @@ struct xilinx_dma_device {
struct clk *rxs_clk;
u32 nr_channels;
u32 chan_id;
+ u32 max_buffer_len;
};
/* Macros */
@@ -957,6 +959,25 @@ static int xilinx_dma_alloc_chan_resources(struct dma_chan
*dchan)
return 0;
}
+/**
+ * xilinx_dma_calc_copysize - Calculate the amount of data to copy
+ * @chan: Driver specific DMA channel
+ * @size: Total data that needs to be copied
+ * @done: Amount of data that has been already copied
+ *
+ * Return: Amount of data that has to be copied
+ */
+static int xilinx_dma_calc_copysize(struct xilinx_dma_chan *chan,
+ int size, int done)
+{
+ size_t copy;
+
+ copy = min_t(size_t, size - done,
+ chan->xdev->max_buffer_len);
+
+ return copy;
+}
+
/**
* xilinx_dma_tx_status - Get DMA transaction status
* @dchan: DMA channel
@@ -990,7 +1011,7 @@ static enum dma_status xilinx_dma_tx_status(struct
dma_chan *dchan,
list_for_each_entry(segment, &desc->segments, node) {
hw = &segment->hw;
residue += (hw->control - hw->status) &
- XILINX_DMA_MAX_TRANS_LEN;
+ chan->xdev->max_buffer_len;
}
}
spin_unlock_irqrestore(&chan->lock, flags);
@@ -1250,7 +1271,7 @@ static void xilinx_cdma_start_transfer(struct
xilinx_dma_chan *chan)
/* Start the transfer */
dma_ctrl_write(chan, XILINX_DMA_REG_BTT,
- hw->control & XILINX_DMA_MAX_TRANS_LEN);
+ hw->control & chan->xdev->max_buffer_len);
}
list_splice_tail_init(&chan->pending_list, &chan->active_list);
@@ -1353,7 +1374,7 @@ static void xilinx_dma_start_transfer(struct
xilinx_dma_chan *chan)
/* Start the transfer */
dma_ctrl_write(chan, XILINX_DMA_REG_BTT,
- hw->control & XILINX_DMA_MAX_TRANS_LEN);
+ hw->control & chan->xdev->max_buffer_len);
}
list_splice_tail_init(&chan->pending_list, &chan->active_list);
@@ -1714,7 +1735,7 @@ xilinx_cdma_prep_memcpy(struct dma_chan *dchan,
dma_addr_t dma_dst,
struct xilinx_cdma_tx_segment *segment;
struct xilinx_cdma_desc_hw *hw;
- if (!len || len > XILINX_DMA_MAX_TRANS_LEN)
+ if (!len || len > chan->xdev->max_buffer_len)
return NULL;
desc = xilinx_dma_alloc_tx_descriptor(chan);
@@ -1804,8 +1825,8 @@ static struct dma_async_tx_descriptor
*xilinx_dma_prep_slave_sg(
* Calculate the maximum number of bytes to transfer,
* making sure it is less than the hw limit
*/
- copy = min_t(size_t, sg_dma_len(sg) - sg_used,
- XILINX_DMA_MAX_TRANS_LEN);
+ copy = xilinx_dma_calc_copysize(chan, sg_dma_len(sg),
+ sg_used);
hw = &segment->hw;
/* Fill in the descriptor */
@@ -1909,8 +1930,8 @@ static struct dma_async_tx_descriptor
*xilinx_dma_prep_dma_cyclic(
* Calculate the maximum number of bytes to transfer,
* making sure it is less than the hw limit
*/
- copy = min_t(size_t, period_len - sg_used,
- XILINX_DMA_MAX_TRANS_LEN);
+ copy = xilinx_dma_calc_copysize(chan, period_len,
+ sg_used);
hw = &segment->hw;
xilinx_axidma_buf(chan, hw, buf_addr, sg_used,
period_len * i);
@@ -2624,6 +2645,8 @@ static int xilinx_dma_probe(struct platform_device *pdev)
/* Retrieve the DMA engine properties from the device tree */
xdev->has_sg = of_property_read_bool(node, "xlnx,include-sg");
+ xdev->max_buffer_len = XILINX_DMA_MAX_TRANS_LEN;
+
if (xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA)
xdev->mcdma = of_property_read_bool(node, "xlnx,mcdma");
--
2.17.1
