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Subject[PATCH 1/2] dmaengine: dma_slave_config: add support for slave port window
Some slave devices uses address window instead of single register for read
and/or write of data. With the src/dst_port_window_size the address window
can be specified and the DMAengine driver should use this information to
correctly set up the transfer to loop within the provided window.

Signed-off-by: Peter Ujfalusi <>
include/linux/dmaengine.h | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index cc535a478bae..689d44327ef3 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -336,6 +336,12 @@ enum dma_slave_buswidth {
* may or may not be applicable on memory sources.
* @dst_maxburst: same as src_maxburst but for destination target
* mutatis mutandis.
+ * @src_port_window_size: The length of the register area the data need to be
+ * written on the device side. It is only used for devices which is using an
+ * area instead of a single register to receive the data. Typically the DMA
+ * loops in this area in order to transfer the data.
+ * @dst_port_window_size: same as src_port_window_size but for the destination
+ * port.
* @device_fc: Flow Controller Settings. Only valid for slave channels. Fill
* with 'true' if peripheral should be flow controller. Direction will be
* selected at Runtime.
@@ -363,6 +369,8 @@ struct dma_slave_config {
enum dma_slave_buswidth dst_addr_width;
u32 src_maxburst;
u32 dst_maxburst;
+ u32 src_port_window_size;
+ u32 dst_port_window_size;
bool device_fc;
unsigned int slave_id;
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