PCI: endpoint: Create configfs entry for each pci_epf_device_id table entry

In order to be able to provide correct driver_data for pci_epf device,
a separate configfs entry for each pci_epf_device_id table entry in
pci_epf_driver is required.

Add support to create configfs entry for each pci_epf_device_id
table entry here.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>

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

@@ -15,6 +15,8 @@
 #include <linux/pci-epf.h>
 #include <linux/pci-ep-cfs.h>
 
+static DEFINE_MUTEX(pci_epf_mutex);
+
 static struct bus_type pci_epf_bus_type;
 static const struct device_type pci_epf_type;
 
@@ -143,7 +145,13 @@ EXPORT_SYMBOL_GPL(pci_epf_alloc_space);
  */
 void pci_epf_unregister_driver(struct pci_epf_driver *driver)
 {
-	pci_ep_cfs_remove_epf_group(driver->group);
+	struct config_group *group;
+
+	mutex_lock(&pci_epf_mutex);
+	list_for_each_entry(group, &driver->epf_group, group_entry)
+		pci_ep_cfs_remove_epf_group(group);
+	list_del(&driver->epf_group);
+	mutex_unlock(&pci_epf_mutex);
 	driver_unregister(&driver->driver);
 }
 EXPORT_SYMBOL_GPL(pci_epf_unregister_driver);
@@ -159,6 +167,8 @@ int __pci_epf_register_driver(struct pci_epf_driver *driver,
 			      struct module *owner)
 {
 	int ret;
+	struct config_group *group;
+	const struct pci_epf_device_id *id;
 
 	if (!driver->ops)
 		return -EINVAL;
@@ -173,7 +183,16 @@ int __pci_epf_register_driver(struct pci_epf_driver *driver,
 	if (ret)
 		return ret;
 
-	driver->group = pci_ep_cfs_add_epf_group(driver->driver.name);
+	INIT_LIST_HEAD(&driver->epf_group);
+
+	id = driver->id_table;
+	while (id->name[0]) {
+		group = pci_ep_cfs_add_epf_group(id->name);
+		mutex_lock(&pci_epf_mutex);
+		list_add_tail(&group->group_entry, &driver->epf_group);
+		mutex_unlock(&pci_epf_mutex);
+		id++;
+	}
 
 	return 0;
 }

include/linux/pci-epf.h

@@ -72,7 +72,7 @@ struct pci_epf_ops {
  * @driver: PCI EPF driver
  * @ops: set of function pointers for performing EPF operations
  * @owner: the owner of the module that registers the PCI EPF driver
- * @group: configfs group corresponding to the PCI EPF driver
+ * @epf_group: list of configfs group corresponding to the PCI EPF driver
  * @id_table: identifies EPF devices for probing
  */
 struct pci_epf_driver {
@@ -82,7 +82,7 @@ struct pci_epf_driver {
 	struct device_driver	driver;
 	struct pci_epf_ops	*ops;
 	struct module		*owner;
-	struct config_group	*group;
+	struct list_head	epf_group;
 	const struct pci_epf_device_id	*id_table;
 };