dmaengine: imx-sdma: refine to load context only once

The context loaded only one time before channel running,but
currently sdma_config_channel() and dma_prep_* duplicated with
sdma_load_context(), so refine it to load context only one time
before channel running and reload after the channel terminated.
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/imx-sdma.c

@@ -377,6 +377,7 @@ struct sdma_channel {
 	unsigned long			watermark_level;
 	u32				shp_addr, per_addr;
 	enum dma_status			status;
+	bool				context_loaded;
 	struct imx_dma_data		data;
 	struct work_struct		terminate_worker;
 };
@@ -970,6 +971,9 @@ static int sdma_load_context(struct sdma_channel *sdmac)
 	int ret;
 	unsigned long flags;
 
+	if (sdmac->context_loaded)
+		return 0;
+
 	if (sdmac->direction == DMA_DEV_TO_MEM)
 		load_address = sdmac->pc_from_device;
 	else if (sdmac->direction == DMA_DEV_TO_DEV)
@@ -1012,6 +1016,8 @@ static int sdma_load_context(struct sdma_channel *sdmac)
 
 	spin_unlock_irqrestore(&sdma->channel_0_lock, flags);
 
+	sdmac->context_loaded = true;
+
 	return ret;
 }
 
@@ -1051,6 +1057,7 @@ static void sdma_channel_terminate_work(struct work_struct *work)
 	sdmac->desc = NULL;
 	spin_unlock_irqrestore(&sdmac->vc.lock, flags);
 	vchan_dma_desc_free_list(&sdmac->vc, &head);
+	sdmac->context_loaded = false;
 }
 
 static int sdma_disable_channel_async(struct dma_chan *chan)