+/*
+ * Fix sconfig's burst size according to dw_dmac. We need to convert them as:
+ * 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.
+ *
+ * NOTE: burst size 2 is not supported by controller.
+ *
+ * This can be done by finding least significant bit set: n & (n - 1)
+ */
+static inline void convert_burst(u32 *maxburst)
+{
+ if (*maxburst > 1)
+ *maxburst = fls(*maxburst) - 2;
+ else
+ *maxburst = 0;
+}
+
+static int
+set_runtime_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
+{
+ struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+
+ /* Check if it is chan is configured for slave transfers */
+ if (!chan->private)
+ return -EINVAL;
+
+ memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
+
+ convert_burst(&dwc->dma_sconfig.src_maxburst);
+ convert_burst(&dwc->dma_sconfig.dst_maxburst);
+
+ return 0;
+}
+