dma: dw: allocate memory in two stages in probe

This makes the probe() function a little bit clearer.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/dw/core.c

@@ -1479,7 +1479,6 @@ static void dw_dma_off(struct dw_dma *dw)
 int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 {
 	struct dw_dma		*dw;
-	size_t			size;
 	bool			autocfg;
 	unsigned int		dw_params;
 	unsigned int		nr_channels;
@@ -1487,6 +1486,13 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 	int			err;
 	int			i;
 
+	dw = devm_kzalloc(chip->dev, sizeof(*dw), GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+
+	dw->regs = chip->regs;
+	chip->dw = dw;
+
 	dw_params = dma_read_byaddr(chip->regs, DW_PARAMS);
 	autocfg = dw_params >> DW_PARAMS_EN & 0x1;
 
@@ -1509,9 +1515,9 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 	else
 		nr_channels = pdata->nr_channels;
 
-	size = sizeof(struct dw_dma) + nr_channels * sizeof(struct dw_dma_chan);
-	dw = devm_kzalloc(chip->dev, size, GFP_KERNEL);
-	if (!dw)
+	dw->chan = devm_kcalloc(chip->dev, nr_channels, sizeof(*dw->chan),
+				GFP_KERNEL);
+	if (!dw->chan)
 		return -ENOMEM;
 
 	dw->clk = devm_clk_get(chip->dev, "hclk");
@@ -1519,9 +1525,6 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 		return PTR_ERR(dw->clk);
 	clk_prepare_enable(dw->clk);
 
-	dw->regs = chip->regs;
-	chip->dw = dw;
-
 	/* Get hardware configuration parameters */
 	if (autocfg) {
 		max_blk_size = dma_readl(dw, MAX_BLK_SIZE);

drivers/dma/dw/regs.h

@@ -252,13 +252,13 @@ struct dw_dma {
 	struct tasklet_struct	tasklet;
 	struct clk		*clk;
 
+	/* channels */
+	struct dw_dma_chan	*chan;
 	u8			all_chan_mask;
 
 	/* hardware configuration */
 	unsigned char		nr_masters;
 	unsigned char		data_width[4];
-
-	struct dw_dma_chan	chan[0];
 };
 
 static inline struct dw_dma_regs __iomem *__dw_regs(struct dw_dma *dw)