usb: gadget: f_ecm: convert to new function interface with backward compatibility

Converting ecm to the new function interface requires converting
the USB ecm's function code and its users.

This patch converts the f_ecm.c to the new function interface.

The file is now compiled into a separate usb_f_ecm.ko module.

The old function interface is provided by means of a preprocessor
conditional directives. After all users are converted, the old interface
can be removed.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/f_ecm.c

@@ -14,10 +14,12 @@
 
 #include <linux/slab.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/device.h>
 #include <linux/etherdevice.h>
 
 #include "u_ether.h"
+#include "u_ecm.h"
 
 
 /*
@@ -687,6 +689,40 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f)
 	int			status;
 	struct usb_ep		*ep;
 
+#ifndef USBF_ECM_INCLUDED
+	struct f_ecm_opts	*ecm_opts;
+
+	if (!can_support_ecm(cdev->gadget))
+		return -EINVAL;
+
+	ecm_opts = container_of(f->fi, struct f_ecm_opts, func_inst);
+
+	/*
+	 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
+	 * configurations are bound in sequence with list_for_each_entry,
+	 * in each configuration its functions are bound in sequence
+	 * with list_for_each_entry, so we assume no race condition
+	 * with regard to ecm_opts->bound access
+	 */
+	if (!ecm_opts->bound) {
+		gether_set_gadget(ecm_opts->net, cdev->gadget);
+		status = gether_register_netdev(ecm_opts->net);
+		if (status)
+			return status;
+		ecm_opts->bound = true;
+	}
+#endif
+	if (ecm_string_defs[0].id == 0) {
+		status = usb_string_ids_tab(c->cdev, ecm_string_defs);
+		if (status)
+			return status;
+
+		ecm_control_intf.iInterface = ecm_string_defs[0].id;
+		ecm_data_intf.iInterface = ecm_string_defs[2].id;
+		ecm_desc.iMACAddress = ecm_string_defs[1].id;
+		ecm_iad_descriptor.iFunction = ecm_string_defs[3].id;
+	}
+
 	/* allocate instance-specific interface IDs */
 	status = usb_interface_id(c, f);
 	if (status < 0)
@@ -796,8 +832,10 @@ fail:
 	return status;
 }
 
+#ifdef USBF_ECM_INCLUDED
+
 static void
-ecm_unbind(struct usb_configuration *c, struct usb_function *f)
+ecm_old_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct f_ecm		*ecm = func_to_ecm(f);
 
@@ -834,17 +872,6 @@ ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
 	if (!can_support_ecm(c->cdev->gadget) || !ethaddr)
 		return -EINVAL;
 
-	if (ecm_string_defs[0].id == 0) {
-		status = usb_string_ids_tab(c->cdev, ecm_string_defs);
-		if (status)
-			return status;
-
-		ecm_control_intf.iInterface = ecm_string_defs[0].id;
-		ecm_data_intf.iInterface = ecm_string_defs[2].id;
-		ecm_desc.iMACAddress = ecm_string_defs[1].id;
-		ecm_iad_descriptor.iFunction = ecm_string_defs[3].id;
-	}
-
 	/* allocate and initialize one new instance */
 	ecm = kzalloc(sizeof *ecm, GFP_KERNEL);
 	if (!ecm)
@@ -861,7 +888,7 @@ ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
 	ecm->port.func.strings = ecm_strings;
 	/* descriptors are per-instance copies */
 	ecm->port.func.bind = ecm_bind;
-	ecm->port.func.unbind = ecm_unbind;
+	ecm->port.func.unbind = ecm_old_unbind;
 	ecm->port.func.set_alt = ecm_set_alt;
 	ecm->port.func.get_alt = ecm_get_alt;
 	ecm->port.func.setup = ecm_setup;
@@ -872,3 +899,99 @@ ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
 		kfree(ecm);
 	return status;
 }
+
+#else
+
+static void ecm_free_inst(struct usb_function_instance *f)
+{
+	struct f_ecm_opts *opts;
+
+	opts = container_of(f, struct f_ecm_opts, func_inst);
+	if (opts->bound)
+		gether_cleanup(netdev_priv(opts->net));
+	else
+		free_netdev(opts->net);
+	kfree(opts);
+}
+
+static struct usb_function_instance *ecm_alloc_inst(void)
+{
+	struct f_ecm_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+
+	opts->func_inst.free_func_inst = ecm_free_inst;
+	opts->net = gether_setup_default();
+	if (IS_ERR(opts->net))
+		return ERR_PTR(PTR_ERR(opts->net));
+
+	return &opts->func_inst;
+}
+
+static void ecm_free(struct usb_function *f)
+{
+	struct f_ecm *ecm;
+
+	ecm = func_to_ecm(f);
+	kfree(ecm);
+}
+
+static void ecm_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct f_ecm		*ecm = func_to_ecm(f);
+
+	DBG(c->cdev, "ecm unbind\n");
+
+	ecm_string_defs[0].id = 0;
+	usb_free_all_descriptors(f);
+
+	kfree(ecm->notify_req->buf);
+	usb_ep_free_request(ecm->notify, ecm->notify_req);
+}
+
+struct usb_function *ecm_alloc(struct usb_function_instance *fi)
+{
+	struct f_ecm	*ecm;
+	struct f_ecm_opts *opts;
+	int status;
+
+	/* allocate and initialize one new instance */
+	ecm = kzalloc(sizeof(*ecm), GFP_KERNEL);
+	if (!ecm)
+		return ERR_PTR(-ENOMEM);
+
+	opts = container_of(fi, struct f_ecm_opts, func_inst);
+
+	/* export host's Ethernet address in CDC format */
+	status = gether_get_host_addr_cdc(opts->net, ecm->ethaddr,
+					  sizeof(ecm->ethaddr));
+	if (status < 12) {
+		kfree(ecm);
+		return ERR_PTR(-EINVAL);
+	}
+	ecm_string_defs[1].s = ecm->ethaddr;
+
+	ecm->port.ioport = netdev_priv(opts->net);
+	ecm->port.cdc_filter = DEFAULT_FILTER;
+
+	ecm->port.func.name = "cdc_ethernet";
+	ecm->port.func.strings = ecm_strings;
+	/* descriptors are per-instance copies */
+	ecm->port.func.bind = ecm_bind;
+	ecm->port.func.unbind = ecm_unbind;
+	ecm->port.func.set_alt = ecm_set_alt;
+	ecm->port.func.get_alt = ecm_get_alt;
+	ecm->port.func.setup = ecm_setup;
+	ecm->port.func.disable = ecm_disable;
+	ecm->port.func.free_func = ecm_free;
+
+	return &ecm->port.func;
+}
+
+DECLARE_USB_FUNCTION_INIT(ecm, ecm_alloc_inst, ecm_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Brownell");
+
+#endif