usb: gadget: f_subset: convert to new function interface with backwar…

…d compatibility

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

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

The file is now compiled into a separate usb_f_subset.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/Kconfig

@@ -523,6 +523,9 @@ config USB_F_PHONET
 config USB_F_EEM
 	tristate
 
+config USB_F_SUBSET
+	tristate
+
 choice
 	tristate "USB Gadget Drivers"
 	default USB_ETH

drivers/usb/gadget/Makefile

@@ -56,6 +56,8 @@ usb_f_phonet-y			:= f_phonet.o
 obj-$(CONFIG_USB_F_PHONET)	+= usb_f_phonet.o
 usb_f_eem-y			:= f_eem.o
 obj-$(CONFIG_USB_F_EEM)		+= usb_f_eem.o
+usb_f_ecm_subset-y		:= f_subset.o
+obj-$(CONFIG_USB_F_SUBSET)	+= usb_f_ecm_subset.o
 
 #
 # USB gadget drivers

drivers/usb/gadget/ether.c

@@ -103,6 +103,7 @@ static inline bool has_rndis(void)
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
 #include "u_ecm.h"
+#define USB_FSUBSET_INCLUDED
 #include "f_subset.c"
 #ifdef	USB_ETH_RNDIS
 #include "f_rndis.c"

drivers/usb/gadget/f_subset.c

@@ -12,11 +12,12 @@
 
 #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_gether.h"
 
 /*
  * This function packages a simple "CDC Subset" Ethernet port with no real
@@ -298,6 +299,35 @@ geth_bind(struct usb_configuration *c, struct usb_function *f)
 	int			status;
 	struct usb_ep		*ep;
 
+#ifndef USB_FSUBSET_INCLUDED
+	struct f_gether_opts	*gether_opts;
+
+	gether_opts = container_of(f->fi, struct f_gether_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 gether_opts->bound access
+	 */
+	if (!gether_opts->bound) {
+		gether_set_gadget(gether_opts->net, cdev->gadget);
+		status = gether_register_netdev(gether_opts->net);
+		if (status)
+			return status;
+		gether_opts->bound = true;
+	}
+#endif
+	/* maybe allocate device-global string IDs */
+	if (geth_string_defs[0].id == 0) {
+		status = usb_string_ids_tab(c->cdev, geth_string_defs);
+		if (status < 0)
+			return status;
+		subset_data_intf.iInterface = geth_string_defs[0].id;
+		ether_desc.iMACAddress = geth_string_defs[1].id;
+	}
+
 	/* allocate instance-specific interface IDs */
 	status = usb_interface_id(c, f);
 	if (status < 0)
@@ -360,8 +390,10 @@ geth_bind(struct usb_configuration *c, struct usb_function *f)
 	return status;
 }
 
+#ifdef USB_FSUBSET_INCLUDED
+
 static void
-geth_unbind(struct usb_configuration *c, struct usb_function *f)
+geth_old_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	geth_string_defs[0].id = 0;
 	usb_free_all_descriptors(f);
@@ -387,18 +419,6 @@ int geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
 	struct f_gether	*geth;
 	int		status;
 
-	if (!ethaddr)
-		return -EINVAL;
-
-	/* maybe allocate device-global string IDs */
-	if (geth_string_defs[0].id == 0) {
-		status = usb_string_ids_tab(c->cdev, geth_string_defs);
-		if (status < 0)
-			return status;
-		subset_data_intf.iInterface = geth_string_defs[0].id;
-		ether_desc.iMACAddress = geth_string_defs[1].id;
-	}
-
 	/* allocate and initialize one new instance */
 	geth = kzalloc(sizeof *geth, GFP_KERNEL);
 	if (!geth)
@@ -414,7 +434,7 @@ int geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
 	geth->port.func.name = "cdc_subset";
 	geth->port.func.strings = geth_strings;
 	geth->port.func.bind = geth_bind;
-	geth->port.func.unbind = geth_unbind;
+	geth->port.func.unbind = geth_old_unbind;
 	geth->port.func.set_alt = geth_set_alt;
 	geth->port.func.disable = geth_disable;
 
@@ -423,3 +443,89 @@ int geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
 		kfree(geth);
 	return status;
 }
+
+#else
+
+static void geth_free_inst(struct usb_function_instance *f)
+{
+	struct f_gether_opts *opts;
+
+	opts = container_of(f, struct f_gether_opts, func_inst);
+	if (opts->bound)
+		gether_cleanup(netdev_priv(opts->net));
+	else
+		free_netdev(opts->net);
+	kfree(opts);
+}
+
+static struct usb_function_instance *geth_alloc_inst(void)
+{
+	struct f_gether_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+
+	opts->func_inst.free_func_inst = geth_free_inst;
+	opts->net = gether_setup_default();
+	if (IS_ERR(opts->net))
+		return ERR_CAST(opts->net);
+
+	return &opts->func_inst;
+}
+
+static void geth_free(struct usb_function *f)
+{
+	struct f_gether *eth;
+
+	eth = func_to_geth(f);
+	kfree(eth);
+}
+
+static void geth_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	geth_string_defs[0].id = 0;
+	usb_free_all_descriptors(f);
+}
+
+static struct usb_function *geth_alloc(struct usb_function_instance *fi)
+{
+	struct f_gether	*geth;
+	struct f_gether_opts *opts;
+	int status;
+
+	/* allocate and initialize one new instance */
+	geth = kzalloc(sizeof(*geth), GFP_KERNEL);
+	if (!geth)
+		return ERR_PTR(-ENOMEM);
+
+	opts = container_of(fi, struct f_gether_opts, func_inst);
+
+	/* export host's Ethernet address in CDC format */
+	status = gether_get_host_addr_cdc(opts->net, geth->ethaddr,
+					  sizeof(geth->ethaddr));
+	if (status < 12) {
+		kfree(geth);
+		return ERR_PTR(-EINVAL);
+	}
+	geth_string_defs[1].s = geth->ethaddr;
+
+	geth->port.ioport = netdev_priv(opts->net);
+	geth->port.cdc_filter = DEFAULT_FILTER;
+
+	geth->port.func.name = "cdc_subset";
+	geth->port.func.strings = geth_strings;
+	geth->port.func.bind = geth_bind;
+	geth->port.func.unbind = geth_unbind;
+	geth->port.func.set_alt = geth_set_alt;
+	geth->port.func.disable = geth_disable;
+	geth->port.func.free_func = geth_free;
+
+	return &geth->port.func;
+}
+
+DECLARE_USB_FUNCTION_INIT(geth, geth_alloc_inst, geth_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Brownell");
+
+#endif

drivers/usb/gadget/g_ffs.c

@@ -30,6 +30,7 @@
 
 #define USBF_ECM_INCLUDED
 #  include "f_ecm.c"
+#define USB_FSUBSET_INCLUDED
 #  include "f_subset.c"
 #  ifdef USB_ETH_RNDIS
 #    include "f_rndis.c"

drivers/usb/gadget/u_gether.h

@@ -0,0 +1,27 @@
+/*
+ * u_gether.h
+ *
+ * Utility definitions for the subset function
+ *
+ * Copyright (c) 2013 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef U_GETHER_H
+#define U_GETHER_H
+
+#include <linux/usb/composite.h>
+
+struct f_gether_opts {
+	struct usb_function_instance	func_inst;
+	struct net_device		*net;
+	bool				bound;
+};
+
+#endif /* U_GETHER_H */