PCI: endpoint: Use EPC's device in dma_alloc_coherent()/dma_free_coherent()

After commit 723288836628 ("of: restrict DMA configuration"),
of_dma_configure() doesn't configure the coherent_dma_mask/dma_mask
of endpoint function device (since it doesn't have a DT node associated
with and hence no dma-ranges property), resulting in
dma_alloc_coherent() (used in pci_epf_alloc_space()) to fail.

Fix it by making dma_alloc_coherent() use EPC's device for allocating
memory address.

Link: http://lkml.kernel.org/r/64d63468-d28f-8fcd-a6f3-cf2a6401c8cb@ti.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
[lorenzo.pieralisi@arm.com: tweaked commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Tested-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
Tested-by: Niklas Cassel <niklas.cassel@axis.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

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

@@ -18,7 +18,6 @@
  */
 
 #include <linux/device.h>
-#include <linux/dma-mapping.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
@@ -371,7 +370,6 @@ EXPORT_SYMBOL_GPL(pci_epc_write_header);
 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;
@@ -383,12 +381,6 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
 		return -EINVAL;
 
 	epf->epc = epc;
-	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);
@@ -503,9 +495,7 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
 	INIT_LIST_HEAD(&epc->pci_epf);
 
 	device_initialize(&epc->dev);
-	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;
 

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

@@ -99,7 +99,7 @@ EXPORT_SYMBOL_GPL(pci_epf_bind);
  */
 void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar)
 {
-	struct device *dev = &epf->dev;
+	struct device *dev = epf->epc->dev.parent;
 
 	if (!addr)
 		return;
@@ -122,7 +122,7 @@ EXPORT_SYMBOL_GPL(pci_epf_free_space);
 void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar)
 {
 	void *space;
-	struct device *dev = &epf->dev;
+	struct device *dev = epf->epc->dev.parent;
 	dma_addr_t phys_addr;
 
 	if (size < 128)