dmaengine/dw_dmac: provide a mechanism to indicate private devices

Some platforms (e.g. Picochip PC3XX) have multiple DMA controllers
where some may be used for slave transfers and others for general
purpose memcpy type transfers. Add a .is_private boolean to the
platform data structure so that controllers can be marked as private
so that the DMA_PRIVATE capability will be set for that controller.
Signed-off-by: NJamie Iles <jamie.iles@picochip.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/dma/dw_dmac.c

@@ -1341,6 +1341,8 @@ static int __init dw_probe(struct platform_device *pdev)
 
 	dma_cap_set(DMA_MEMCPY, dw->dma.cap_mask);
 	dma_cap_set(DMA_SLAVE, dw->dma.cap_mask);
+	if (pdata->is_private)
+		dma_cap_set(DMA_PRIVATE, dw->dma.cap_mask);
 	dw->dma.dev = &pdev->dev;
 	dw->dma.device_alloc_chan_resources = dwc_alloc_chan_resources;
 	dw->dma.device_free_chan_resources = dwc_free_chan_resources;

include/linux/dw_dmac.h

@@ -16,9 +16,12 @@
 /**
  * struct dw_dma_platform_data - Controller configuration parameters
  * @nr_channels: Number of channels supported by hardware (max 8)
+ * @is_private: The device channels should be marked as private and not for
+ *	by the general purpose DMA channel allocator.
  */
 struct dw_dma_platform_data {
 	unsigned int	nr_channels;
+	bool		is_private;
 };
 
 /**