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authorSascha Hauer <s.hauer@pengutronix.de>2019-05-21 10:06:41 +0300
committerMiquel Raynal <miquel.raynal@bootlin.com>2019-06-27 21:05:29 +0300
commite0ddaab76802d3179013f4864535043e2aea6c69 (patch)
tree992fba574f07acb858f55e728b3f566f8bde2ab1 /include/linux/dma
parent475345e89ced298afbeefed6c86122bb8415593d (diff)
downloadlinux-e0ddaab76802d3179013f4864535043e2aea6c69.tar.xz
dmaengine: mxs: Add header file to be shared with gpmi nand driver
The mxs dma driver can do PIO transfers. A pointer to the PIO words to transfer is passed in the struct scatterlist * argument of dmaengine_prep_slave_sg(). It's quite ugly and non obvious to cast u32 * to struct scatterlist * each time when calling dmaengine_prep_slave_sg(), so add a static inline wrapper function to be called by the user along with a description what is going on. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Diffstat (limited to 'include/linux/dma')
-rw-r--r--include/linux/dma/mxs-dma.h21
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/dma/mxs-dma.h b/include/linux/dma/mxs-dma.h
new file mode 100644
index 000000000000..092b2a7b92ac
--- /dev/null
+++ b/include/linux/dma/mxs-dma.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _MXS_DMA_H_
+#define _MXS_DMA_H_
+
+#include <linux/dmaengine.h>
+
+/*
+ * The mxs dmaengine can do PIO transfers. We pass a pointer to the PIO words
+ * in the second argument to dmaengine_prep_slave_sg when the direction is
+ * set to DMA_TRANS_NONE. To make this clear and to prevent users from doing
+ * the error prone casting we have this wrapper function
+ */
+static inline struct dma_async_tx_descriptor *mxs_dmaengine_prep_pio(
+ struct dma_chan *chan, u32 *pio, unsigned int npio,
+ enum dma_transfer_direction dir, unsigned long flags)
+{
+ return dmaengine_prep_slave_sg(chan, (struct scatterlist *)pio, npio,
+ dir, flags);
+}
+
+#endif /* _MXS_DMA_H_ */