PCI: endpoint: Use of_dma_configure() to set initial DMA mask

Use of_dma_configure() to set the initial DMA mask of EPF device. This
helps to get rid of "Coherent DMA mask 0x0 (pfn 0x0-0x1) covers a smaller
range of system memory than the DMA zone pfn" warning in certain platforms
like TI's K2G resulting in coherent DMA mask not being set.

Signed-off-by: Kishon Vijay Abraham I <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>

drivers/pci/endpoint/pci-epc-core.c

···
 #include <linux/dma-mapping.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
 
 #include <linux/pci-epc.h>
 #include <linux/pci-epf.h>
···
 int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
 {
 	unsigned long flags;
+	struct device *dev = epc->dev.parent;
 
 	if (epf->epc)
 		return -EBUSY;
···
 		return -EINVAL;
 
 	epf->epc = epc;
-	dma_set_coherent_mask(&epf->dev, epc->dev.coherent_dma_mask);
-	epf->dev.dma_mask = epc->dev.dma_mask;
+	if (dev->of_node) {
+		of_dma_configure(&epf->dev, dev->of_node);
+	} else {
+		dma_set_coherent_mask(&epf->dev, epc->dev.coherent_dma_mask);
+		epf->dev.dma_mask = epc->dev.dma_mask;
+	}
 
 	spin_lock_irqsave(&epc->lock, flags);
 	list_add_tail(&epf->list, &epc->pci_epf);
···
 	dma_set_coherent_mask(&epc->dev, dev->coherent_dma_mask);
 	epc->dev.class = pci_epc_class;
 	epc->dev.dma_mask = dev->dma_mask;
+	epc->dev.parent = dev;
 	epc->ops = ops;
 
 	ret = dev_set_name(&epc->dev, "%s", dev_name(dev));