dmaengine: stm32-dma: threshold manages with bitfield feature

>From now on, DMA bitfield is to manage DMA FIFO Threshold.
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/stm32-dma.c

@@ -116,6 +116,10 @@
 #define STM32_DMA_MAX_DATA_PARAM	0x03
 #define STM32_DMA_MAX_BURST		16
 
+/* DMA Features */
+#define STM32_DMA_THRESHOLD_FTR_MASK	GENMASK(1, 0)
+#define STM32_DMA_THRESHOLD_FTR_GET(n)	((n) & STM32_DMA_THRESHOLD_FTR_MASK)
+
 enum stm32_dma_width {
 	STM32_DMA_BYTE,
 	STM32_DMA_HALF_WORD,
@@ -129,11 +133,18 @@ enum stm32_dma_burst_size {
 	STM32_DMA_BURST_INCR16,
 };
 
+/**
+ * struct stm32_dma_cfg - STM32 DMA custom configuration
+ * @channel_id: channel ID
+ * @request_line: DMA request
+ * @stream_config: 32bit mask specifying the DMA channel configuration
+ * @features: 32bit mask specifying the DMA Feature list
+ */
 struct stm32_dma_cfg {
 	u32 channel_id;
 	u32 request_line;
 	u32 stream_config;
-	u32 threshold;
+	u32 features;
 };
 
 struct stm32_dma_chan_reg {
@@ -171,6 +182,7 @@ struct stm32_dma_chan {
 	u32 next_sg;
 	struct dma_slave_config	dma_sconfig;
 	struct stm32_dma_chan_reg chan_reg;
+	u32 threshold;
 };
 
 struct stm32_dma_device {
@@ -976,7 +988,8 @@ static void stm32_dma_set_config(struct stm32_dma_chan *chan,
 	/* Enable Interrupts  */
 	chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE;
 
-	chan->chan_reg.dma_sfcr = cfg->threshold & STM32_DMA_SFCR_FTH_MASK;
+	chan->threshold = STM32_DMA_THRESHOLD_FTR_GET(cfg->features);
+	chan->chan_reg.dma_sfcr = STM32_DMA_SFCR_FTH(chan->threshold);
 }
 
 static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec,
@@ -996,7 +1009,7 @@ static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec,
 	cfg.channel_id = dma_spec->args[0];
 	cfg.request_line = dma_spec->args[1];
 	cfg.stream_config = dma_spec->args[2];
-	cfg.threshold = dma_spec->args[3];
+	cfg.features = dma_spec->args[3];
 
 	if ((cfg.channel_id >= STM32_DMA_MAX_CHANNELS) ||
 	    (cfg.request_line >= STM32_DMA_MAX_REQUEST_ID)) {