dmaengine: imx-sdma: add a test for imx8mq multi sdma devices

On i.mx8mq, there are two sdma instances, and the common dma framework
will get a channel dynamically from any available sdma instance whether
it's the first sdma device or the second sdma device. Some IPs like
SAI only work with sdma2 not sdma1. To make sure the sdma channel is from
the correct sdma device, use the node pointer to match.
Signed-off-by: Angus Ainslie (Purism) <angus@akkea.ca>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/imx-sdma.c

@@ -1913,11 +1913,16 @@ static int sdma_init(struct sdma_engine *sdma)
 static bool sdma_filter_fn(struct dma_chan *chan, void *fn_param)
 {
 	struct sdma_channel *sdmac = to_sdma_chan(chan);
+	struct sdma_engine *sdma = sdmac->sdma;
 	struct imx_dma_data *data = fn_param;
 
 	if (!imx_dma_is_general_purpose(chan))
 		return false;
 
+	/* return false if it's not the right device */
+	if (sdma->dev->of_node != data->of_node)
+		return false;
+
 	sdmac->data = *data;
 	chan->private = &sdmac->data;
 
@@ -1945,6 +1950,7 @@ static struct dma_chan *sdma_xlate(struct of_phandle_args *dma_spec,
 	 * be set to sdmac->event_id1.
 	 */
 	data.dma_request2 = 0;
+	data.of_node = ofdma->of_node;
 
 	return dma_request_channel(mask, sdma_filter_fn, &data);
 }

include/linux/platform_data/dma-imx.h

@@ -55,6 +55,7 @@ struct imx_dma_data {
 	int dma_request2; /* secondary DMA request line */
 	enum sdma_peripheral_type peripheral_type;
 	int priority;
+	struct device_node *of_node;
 };
 
 static inline int imx_dma_is_ipu(struct dma_chan *chan)