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

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

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

The file is now compiled into a separate usb_f_eem.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

@@ -520,6 +520,9 @@ config USB_F_ECM
 config USB_F_PHONET
 	tristate
 
+config USB_F_EEM
+	tristate
+
 choice
 	tristate "USB Gadget Drivers"
 	default USB_ETH

drivers/usb/gadget/Makefile

@@ -54,6 +54,8 @@ usb_f_ecm-y			:= f_ecm.o
 obj-$(CONFIG_USB_F_ECM)		+= usb_f_ecm.o
 usb_f_phonet-y			:= f_phonet.o
 obj-$(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 gadget drivers

drivers/usb/gadget/ether.c

@@ -108,6 +108,8 @@ static inline bool has_rndis(void)
 #include "f_rndis.c"
 #include "rndis.h"
 #endif
+
+#define USB_FEEM_INCLUDED
 #include "f_eem.c"
 
 /*-------------------------------------------------------------------------*/

drivers/usb/gadget/f_eem.c

@@ -12,12 +12,14 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/device.h>
 #include <linux/etherdevice.h>
 #include <linux/crc32.h>
 #include <linux/slab.h>
 
 #include "u_ether.h"
+#include "u_eem.h"
 
 #define EEM_HLEN 2
 
@@ -40,7 +42,7 @@ static inline struct f_eem *func_to_eem(struct usb_function *f)
 
 /* interface descriptor: */
 
-static struct usb_interface_descriptor eem_intf __initdata = {
+static struct usb_interface_descriptor eem_intf = {
 	.bLength =		sizeof eem_intf,
 	.bDescriptorType =	USB_DT_INTERFACE,
 
@@ -54,7 +56,7 @@ static struct usb_interface_descriptor eem_intf __initdata = {
 
 /* full speed support: */
 
-static struct usb_endpoint_descriptor eem_fs_in_desc __initdata = {
+static struct usb_endpoint_descriptor eem_fs_in_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 
@@ -62,7 +64,7 @@ static struct usb_endpoint_descriptor eem_fs_in_desc __initdata = {
 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
 };
 
-static struct usb_endpoint_descriptor eem_fs_out_desc __initdata = {
+static struct usb_endpoint_descriptor eem_fs_out_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 
@@ -70,7 +72,7 @@ static struct usb_endpoint_descriptor eem_fs_out_desc __initdata = {
 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
 };
 
-static struct usb_descriptor_header *eem_fs_function[] __initdata = {
+static struct usb_descriptor_header *eem_fs_function[] = {
 	/* CDC EEM control descriptors */
 	(struct usb_descriptor_header *) &eem_intf,
 	(struct usb_descriptor_header *) &eem_fs_in_desc,
@@ -80,7 +82,7 @@ static struct usb_descriptor_header *eem_fs_function[] __initdata = {
 
 /* high speed support: */
 
-static struct usb_endpoint_descriptor eem_hs_in_desc __initdata = {
+static struct usb_endpoint_descriptor eem_hs_in_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 
@@ -89,7 +91,7 @@ static struct usb_endpoint_descriptor eem_hs_in_desc __initdata = {
 	.wMaxPacketSize =	cpu_to_le16(512),
 };
 
-static struct usb_endpoint_descriptor eem_hs_out_desc __initdata = {
+static struct usb_endpoint_descriptor eem_hs_out_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 
@@ -98,7 +100,7 @@ static struct usb_endpoint_descriptor eem_hs_out_desc __initdata = {
 	.wMaxPacketSize =	cpu_to_le16(512),
 };
 
-static struct usb_descriptor_header *eem_hs_function[] __initdata = {
+static struct usb_descriptor_header *eem_hs_function[] = {
 	/* CDC EEM control descriptors */
 	(struct usb_descriptor_header *) &eem_intf,
 	(struct usb_descriptor_header *) &eem_hs_in_desc,
@@ -108,7 +110,7 @@ static struct usb_descriptor_header *eem_hs_function[] __initdata = {
 
 /* super speed support: */
 
-static struct usb_endpoint_descriptor eem_ss_in_desc __initdata = {
+static struct usb_endpoint_descriptor eem_ss_in_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 
@@ -117,7 +119,7 @@ static struct usb_endpoint_descriptor eem_ss_in_desc __initdata = {
 	.wMaxPacketSize =	cpu_to_le16(1024),
 };
 
-static struct usb_endpoint_descriptor eem_ss_out_desc __initdata = {
+static struct usb_endpoint_descriptor eem_ss_out_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 
@@ -126,7 +128,7 @@ static struct usb_endpoint_descriptor eem_ss_out_desc __initdata = {
 	.wMaxPacketSize =	cpu_to_le16(1024),
 };
 
-static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc __initdata = {
+static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc = {
 	.bLength =		sizeof eem_ss_bulk_comp_desc,
 	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
 
@@ -135,7 +137,7 @@ static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc __initdata = {
 	/* .bmAttributes =	0, */
 };
 
-static struct usb_descriptor_header *eem_ss_function[] __initdata = {
+static struct usb_descriptor_header *eem_ss_function[] = {
 	/* CDC EEM control descriptors */
 	(struct usb_descriptor_header *) &eem_intf,
 	(struct usb_descriptor_header *) &eem_ss_in_desc,
@@ -242,14 +244,44 @@ static void eem_disable(struct usb_function *f)
 
 /* EEM function driver setup/binding */
 
-static int __init
-eem_bind(struct usb_configuration *c, struct usb_function *f)
+static int eem_bind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct usb_composite_dev *cdev = c->cdev;
 	struct f_eem		*eem = func_to_eem(f);
 	int			status;
 	struct usb_ep		*ep;
 
+#ifndef USB_FEEM_INCLUDED
+	struct f_eem_opts	*eem_opts;
+
+	eem_opts = container_of(f->fi, struct f_eem_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 eem_opts->bound access
+	 */
+	if (!eem_opts->bound) {
+		gether_set_gadget(eem_opts->net, cdev->gadget);
+		status = gether_register_netdev(eem_opts->net);
+		if (status)
+			return status;
+		eem_opts->bound = true;
+	}
+#endif
+
+	/* maybe allocate device-global string IDs */
+	if (eem_string_defs[0].id == 0) {
+
+		/* control interface label */
+		status = usb_string_id(c->cdev);
+		if (status < 0)
+			return status;
+		eem_string_defs[0].id = status;
+		eem_intf.iInterface = status;
+	}
+
 	/* allocate instance-specific interface IDs */
 	status = usb_interface_id(c, f);
 	if (status < 0)
@@ -307,17 +339,6 @@ fail:
 	return status;
 }
 
-static void
-eem_unbind(struct usb_configuration *c, struct usb_function *f)
-{
-	struct f_eem	*eem = func_to_eem(f);
-
-	DBG(c->cdev, "eem unbind\n");
-
-	usb_free_all_descriptors(f);
-	kfree(eem);
-}
-
 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
 {
 	struct sk_buff *skb = (struct sk_buff *)req->context;
@@ -518,6 +539,18 @@ error:
 	return status;
 }
 
+#ifdef USB_FEEM_INCLUDED
+
+static void eem_old_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct f_eem	*eem = func_to_eem(f);
+
+	DBG(c->cdev, "eem unbind\n");
+
+	usb_free_all_descriptors(f);
+	kfree(eem);
+}
+
 /**
  * eem_bind_config - add CDC Ethernet (EEM) network link to a configuration
  * @c: the configuration to support the network link
@@ -533,17 +566,6 @@ int __init eem_bind_config(struct usb_configuration *c, struct eth_dev *dev)
 	struct f_eem	*eem;
 	int		status;
 
-	/* maybe allocate device-global string IDs */
-	if (eem_string_defs[0].id == 0) {
-
-		/* control interface label */
-		status = usb_string_id(c->cdev);
-		if (status < 0)
-			return status;
-		eem_string_defs[0].id = status;
-		eem_intf.iInterface = status;
-	}
-
 	/* allocate and initialize one new instance */
 	eem = kzalloc(sizeof *eem, GFP_KERNEL);
 	if (!eem)
@@ -556,7 +578,7 @@ int __init eem_bind_config(struct usb_configuration *c, struct eth_dev *dev)
 	eem->port.func.strings = eem_strings;
 	/* descriptors are per-instance copies */
 	eem->port.func.bind = eem_bind;
-	eem->port.func.unbind = eem_unbind;
+	eem->port.func.unbind = eem_old_unbind;
 	eem->port.func.set_alt = eem_set_alt;
 	eem->port.func.setup = eem_setup;
 	eem->port.func.disable = eem_disable;
@@ -570,3 +592,83 @@ int __init eem_bind_config(struct usb_configuration *c, struct eth_dev *dev)
 	return status;
 }
 
+#else
+
+static void eem_free_inst(struct usb_function_instance *f)
+{
+	struct f_eem_opts *opts;
+
+	opts = container_of(f, struct f_eem_opts, func_inst);
+	if (opts->bound)
+		gether_cleanup(netdev_priv(opts->net));
+	else
+		free_netdev(opts->net);
+	kfree(opts);
+}
+
+static struct usb_function_instance *eem_alloc_inst(void)
+{
+	struct f_eem_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+	opts->func_inst.free_func_inst = eem_free_inst;
+	opts->net = gether_setup_default();
+	if (IS_ERR(opts->net))
+		return ERR_CAST(opts->net);
+
+	return &opts->func_inst;
+}
+
+static void eem_free(struct usb_function *f)
+{
+	struct f_eem *eem;
+
+	eem = func_to_eem(f);
+	kfree(eem);
+}
+
+static void eem_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	DBG(c->cdev, "eem unbind\n");
+
+	usb_free_all_descriptors(f);
+}
+
+struct usb_function *eem_alloc(struct usb_function_instance *fi)
+{
+	struct f_eem	*eem;
+	struct f_eem_opts *opts;
+
+	/* allocate and initialize one new instance */
+	eem = kzalloc(sizeof(*eem), GFP_KERNEL);
+	if (!eem)
+		return ERR_PTR(-ENOMEM);
+
+	opts = container_of(fi, struct f_eem_opts, func_inst);
+
+	eem->port.ioport = netdev_priv(opts->net);
+	eem->port.cdc_filter = DEFAULT_FILTER;
+
+	eem->port.func.name = "cdc_eem";
+	eem->port.func.strings = eem_strings;
+	/* descriptors are per-instance copies */
+	eem->port.func.bind = eem_bind;
+	eem->port.func.unbind = eem_unbind;
+	eem->port.func.set_alt = eem_set_alt;
+	eem->port.func.setup = eem_setup;
+	eem->port.func.disable = eem_disable;
+	eem->port.func.free_func = eem_free;
+	eem->port.wrap = eem_wrap;
+	eem->port.unwrap = eem_unwrap;
+	eem->port.header_len = EEM_HLEN;
+
+	return &eem->port.func;
+}
+
+DECLARE_USB_FUNCTION_INIT(eem, eem_alloc_inst, eem_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Brownell");
+
+#endif

drivers/usb/gadget/u_eem.h

@@ -0,0 +1,27 @@
+/*
+ * u_eem.h
+ *
+ * Utility definitions for the eem 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_EEM_H
+#define U_EEM_H
+
+#include <linux/usb/composite.h>
+
+struct f_eem_opts {
+	struct usb_function_instance	func_inst;
+	struct net_device		*net;
+	bool				bound;
+};
+
+#endif /* U_EEM_H */