PCI/portdrv: Add generic pcie_port_find_device()

Add generic pcie_port_find_device() routine.
Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>

drivers/pci/pcie/portdrv.h

@@ -114,4 +114,5 @@ static inline void pcie_pme_interrupt_enable(struct pci_dev *dev, bool en) {}
 
 struct pcie_port_service_driver *pcie_port_find_service(struct pci_dev *dev,
 							u32 service);
+struct device *pcie_port_find_device(struct pci_dev *dev, u32 service);
 #endif /* _PORTDRV_H_ */

drivers/pci/pcie/portdrv_core.c

@@ -21,6 +21,7 @@
 
 struct portdrv_service_data {
 	struct pcie_port_service_driver *drv;
+	struct device *dev;
 	u32 service;
 };
 
@@ -416,6 +417,7 @@ static int find_service_iter(struct device *device, void *data)
 		service_driver = to_service_driver(device->driver);
 		if (service_driver->service == service) {
 			pdrvs->drv = service_driver;
+			pdrvs->dev = device;
 			return 1;
 		}
 	}
@@ -444,6 +446,27 @@ struct pcie_port_service_driver *pcie_port_find_service(struct pci_dev *dev,
 	return drv;
 }
 
+/**
+ * pcie_port_find_device - find the struct device
+ * @dev: PCI Express port the service is associated with
+ * @service: For the service to find
+ *
+ * Find the struct device associated with given service on a pci_dev
+ */
+struct device *pcie_port_find_device(struct pci_dev *dev,
+				      u32 service)
+{
+	struct device *device;
+	struct portdrv_service_data pdrvs;
+
+	pdrvs.dev = NULL;
+	pdrvs.service = service;
+	device_for_each_child(&dev->dev, &pdrvs, find_service_iter);
+
+	device = pdrvs.dev;
+	return device;
+}
+
 /**
  * pcie_port_device_remove - unregister PCI Express port service devices
  * @dev: PCI Express port the service devices to unregister are associated with