linux-kernel - [PATCH v4 1/7] dmaengine: xilinx_dma: commonize DMA copy size calculation

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Message-Id: <20180802141012.19970-1-andrea.merello@gmail.com>
Date:   Thu,  2 Aug 2018 16:10:06 +0200
From:   Andrea Merello <andrea.merello@...il.com>
To:     vkoul@...nel.org, dan.j.williams@...el.com,
        michal.simek@...inx.com, appana.durga.rao@...inx.com,
        dmaengine@...r.kernel.org
Cc:     v4-000linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, robh+dt@...nel.org,
        mark.rutland@....com, devicetree@...r.kernel.org,
        radhey.shyam.pandey@...inx.com,
        Andrea Merello <andrea.merello@...il.com>
Subject: [PATCH v4 1/7] dmaengine: xilinx_dma: commonize DMA copy size calculation

This patch removes a bit of duplicated code by introducing a new
function that implements calculations for DMA copy size.

Suggested-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Andrea Merello <andrea.merello@...il.com>
---
Changes in v4:
	- introduce this patch in the patch series
---
 drivers/dma/xilinx/xilinx_dma.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index 27b523530c4a..a3aaa0e34cc7 100644
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c
@@ -952,6 +952,19 @@ static int xilinx_dma_alloc_chan_resources(struct dma_chan *dchan)
 	return 0;
 }
 
+/**
+ * xilinx_dma_calc_copysize - Calculate the amount of data to copy
+ * @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(int size, int done)
+{
+	return min_t(size_t, size - done,
+		     XILINX_DMA_MAX_TRANS_LEN);
+}
+
 /**
  * xilinx_dma_tx_status - Get DMA transaction status
  * @dchan: DMA channel
@@ -1791,8 +1804,8 @@ 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(sg_dma_len(sg),
+							sg_used);
 			hw = &segment->hw;
 
 			/* Fill in the descriptor */
@@ -1896,8 +1909,7 @@ 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(period_len, sg_used);
 			hw = &segment->hw;
 			xilinx_axidma_buf(chan, hw, buf_addr, sg_used,
 					  period_len * i);
-- 
2.17.1