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 <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index cc535a478bae6d6e5834371f70f25a0cb9dbc981..feee6ec6a13bbba6762618c21812754e3320684d 100644 (file)
--- 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 in words the data need
+ * to be accessed 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;
 };