[PATCHv2] dw_dmac: absence of pdata isn't critical when autocfg is set

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

The patch allows to probe the device when platform data is absent and hardware
auto configuration is enabled. In that case the default platform data is used
where the channel allocation order is set to ascending, channel priority is set
to ascending, and private property is set to true.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
Since v1:
 - allocate memory for pdata dynamically

 drivers/dma/dw_dmac.c |   23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 2c8096d..a4a5c80 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -1600,13 +1600,6 @@ static int __devinit dw_probe(struct platform_device *pdev)
 	int			err;
 	int			i;
 
-	pdata = dev_get_platdata(&pdev->dev);
-	if (!pdata)
-		pdata = dw_dma_parse_dt(pdev);
-
-	if (!pdata || pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS)
-		return -EINVAL;
-
 	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!io)
 		return -EINVAL;
@@ -1622,6 +1615,22 @@ static int __devinit dw_probe(struct platform_device *pdev)
 	dw_params = dma_read_byaddr(regs, DW_PARAMS);
 	autocfg = dw_params >> DW_PARAMS_EN & 0x1;
 
+	pdata = dev_get_platdata(&pdev->dev);
+	if (!pdata)
+		pdata = dw_dma_parse_dt(pdev);
+
+	if (!pdata && autocfg) {
+		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+		if (!pdata)
+			return -ENOMEM;
+
+		/* Fill platform data with the default values */
+		pdata->is_private = true;
+		pdata->chan_allocation_order = CHAN_ALLOCATION_ASCENDING;
+		pdata->chan_priority = CHAN_PRIORITY_ASCENDING;
+	} else if (!pdata || pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS)
+		return -EINVAL;
+
 	if (autocfg)
 		nr_channels = (dw_params >> DW_PARAMS_NR_CHAN & 0x7) + 1;
 	else
-- 
1.7.10.4