[PATCH 2/2] dw_dmac: check for mapping errors

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

Otherwise we get a warning in case of CONFIG_DMA_API_DEBUG=y

[   45.775943] WARNING: at lib/dma-debug.c:933 check_unmap+0x5d6/0x6ac()
[   45.782369] dw_dmac dw_dmac.0: DMA-API: device driver failed to check map error[device address=0x00000000356efcc0] [size=28 bytes] [mapped as single]

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/dma/dw_dmac.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index a9e9a07..38eea0c 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -1107,6 +1107,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 	struct dw_desc		*desc;
 	int			i;
 	unsigned long		flags;
+	int			ret = 0;
 
 	dev_vdbg(chan2dev(chan), "%s\n", __func__);
 
@@ -1131,8 +1132,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 
 		desc = kzalloc(sizeof(struct dw_desc), GFP_KERNEL);
 		if (!desc) {
-			dev_info(chan2dev(chan),
-				"only allocated %d descriptors\n", i);
+			ret = -ENOMEM;
 			spin_lock_irqsave(&dwc->lock, flags);
 			break;
 		}
@@ -1143,6 +1143,13 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 		desc->txd.flags = DMA_CTRL_ACK;
 		desc->txd.phys = dma_map_single(chan2parent(chan), &desc->lli,
 				sizeof(desc->lli), DMA_TO_DEVICE);
+		ret = dma_mapping_error(chan2parent(chan), desc->txd.phys);
+		if (ret) {
+			kfree(desc);
+			spin_lock_irqsave(&dwc->lock, flags);
+			break;
+		}
+
 		dwc_desc_put(dwc, desc);
 
 		spin_lock_irqsave(&dwc->lock, flags);
@@ -1151,6 +1158,9 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	if (ret)
+		dev_info(chan2dev(chan), "only allocated %d descriptors\n", i);
+
 	dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
 
 	return i;
-- 
1.7.10.4