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

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

This patch converts the f_midi.c to the new function interface.
The file can now be compiled into a separate usb_f_midi.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: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/Kconfig

@@ -190,6 +190,9 @@ config USB_F_UAC2
 config USB_F_UVC
 	tristate
 
+config USB_F_MIDI
+	tristate
+
 choice
 	tristate "USB Gadget Drivers"
 	default USB_ETH

drivers/usb/gadget/function/Makefile

@@ -38,3 +38,5 @@ usb_f_uac2-y			:= f_uac2.o
 obj-$(CONFIG_USB_F_UAC2)	+= usb_f_uac2.o
 usb_f_uvc-y			:= f_uvc.o uvc_queue.o uvc_v4l2.o uvc_video.o
 obj-$(CONFIG_USB_F_UVC)		+= usb_f_uvc.o
+usb_f_midi-y			:= f_midi.o
+obj-$(CONFIG_USB_F_MIDI)	+= usb_f_midi.o

drivers/usb/gadget/function/f_midi.c

@@ -20,6 +20,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/device.h>
 
@@ -33,6 +34,7 @@
 #include <linux/usb/midi.h>
 
 #include "u_f.h"
+#include "u_midi.h"
 
 MODULE_AUTHOR("Ben Williamson");
 MODULE_LICENSE("GPL v2");
@@ -99,7 +101,7 @@ DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(1);
 DECLARE_USB_MS_ENDPOINT_DESCRIPTOR(16);
 
 /* B.3.1  Standard AC Interface Descriptor */
-static struct usb_interface_descriptor ac_interface_desc __initdata = {
+static struct usb_interface_descriptor ac_interface_desc = {
 	.bLength =		USB_DT_INTERFACE_SIZE,
 	.bDescriptorType =	USB_DT_INTERFACE,
 	/* .bInterfaceNumber =	DYNAMIC */
@@ -110,7 +112,7 @@ static struct usb_interface_descriptor ac_interface_desc __initdata = {
 };
 
 /* B.3.2  Class-Specific AC Interface Descriptor */
-static struct uac1_ac_header_descriptor_1 ac_header_desc __initdata = {
+static struct uac1_ac_header_descriptor_1 ac_header_desc = {
 	.bLength =		UAC_DT_AC_HEADER_SIZE(1),
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	USB_MS_HEADER,
@@ -121,7 +123,7 @@ static struct uac1_ac_header_descriptor_1 ac_header_desc __initdata = {
 };
 
 /* B.4.1  Standard MS Interface Descriptor */
-static struct usb_interface_descriptor ms_interface_desc __initdata = {
+static struct usb_interface_descriptor ms_interface_desc = {
 	.bLength =		USB_DT_INTERFACE_SIZE,
 	.bDescriptorType =	USB_DT_INTERFACE,
 	/* .bInterfaceNumber =	DYNAMIC */
@@ -132,7 +134,7 @@ static struct usb_interface_descriptor ms_interface_desc __initdata = {
 };
 
 /* B.4.2  Class-Specific MS Interface Descriptor */
-static struct usb_ms_header_descriptor ms_header_desc __initdata = {
+static struct usb_ms_header_descriptor ms_header_desc = {
 	.bLength =		USB_DT_MS_HEADER_SIZE,
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	USB_MS_HEADER,
@@ -387,6 +389,7 @@ static void f_midi_disable(struct usb_function *f)
 	usb_ep_disable(midi->out_ep);
 }
 
+#ifdef USBF_MIDI_INCLUDED
 static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct usb_composite_dev *cdev = f->config->cdev;
@@ -409,6 +412,7 @@ static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
 	usb_free_all_descriptors(f);
 	kfree(midi);
 }
+#endif
 
 static int f_midi_snd_free(struct snd_device *device)
 {
@@ -729,8 +733,7 @@ static int f_midi_register_card(struct f_midi *midi)
 
 /* MIDI function driver setup/binding */
 
-static int __init
-f_midi_bind(struct usb_configuration *c, struct usb_function *f)
+static int f_midi_bind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct usb_descriptor_header **midi_function;
 	struct usb_midi_in_jack_descriptor jack_in_ext_desc[MAX_PORTS];
@@ -741,6 +744,14 @@ f_midi_bind(struct usb_configuration *c, struct usb_function *f)
 	struct f_midi *midi = func_to_midi(f);
 	int status, n, jack = 1, i = 0;
 
+#ifndef USBF_MIDI_INCLUDED
+	midi->gadget = cdev->gadget;
+	tasklet_init(&midi->tasklet, f_midi_in_tasklet, (unsigned long) midi);
+	status = f_midi_register_card(midi);
+	if (status < 0)
+		goto fail_register;
+
+#endif
 	/* maybe allocate device-global string ID */
 	if (midi_string_defs[0].id == 0) {
 		status = usb_string_id(c->cdev);
@@ -897,6 +908,10 @@ f_midi_bind(struct usb_configuration *c, struct usb_function *f)
 	kfree(midi_function);
 	usb_free_descriptors(f->hs_descriptors);
 fail:
+#ifndef USBF_MIDI_INCLUDED
+	f_midi_unregister_card(midi);
+fail_register:
+#endif
 	/* we might as well release our claims on endpoints */
 	if (midi->out_ep)
 		midi->out_ep->driver_data = NULL;
@@ -908,6 +923,7 @@ f_midi_bind(struct usb_configuration *c, struct usb_function *f)
 	return status;
 }
 
+#ifdef USBF_MIDI_INCLUDED
 /**
  * f_midi_bind_config - add USB MIDI function to a configuration
  * @c: the configuration to supcard the USB audio function
@@ -997,3 +1013,122 @@ int __init f_midi_bind_config(struct usb_configuration *c,
 	return status;
 }
 
+#else
+
+static void f_midi_free_inst(struct usb_function_instance *f)
+{
+	struct f_midi_opts *opts;
+
+	opts = container_of(f, struct f_midi_opts, func_inst);
+
+	kfree(opts);
+}
+
+static struct usb_function_instance *f_midi_alloc_inst(void)
+{
+	struct f_midi_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+	opts->func_inst.free_func_inst = f_midi_free_inst;
+
+	return &opts->func_inst;
+}
+
+static void f_midi_free(struct usb_function *f)
+{
+	struct f_midi *midi;
+	struct f_midi_opts *opts;
+	int i;
+
+	midi = func_to_midi(f);
+	opts = container_of(f->fi, struct f_midi_opts, func_inst);
+	kfree(midi->id);
+	for (i = opts->in_ports - 1; i >= 0; --i)
+		kfree(midi->in_port[i]);
+	kfree(midi);
+}
+
+static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_composite_dev *cdev = f->config->cdev;
+	struct f_midi *midi = func_to_midi(f);
+	struct snd_card *card;
+
+	DBG(cdev, "unbind\n");
+
+	/* just to be sure */
+	f_midi_disable(f);
+
+	card = midi->card;
+	midi->card = NULL;
+	if (card)
+		snd_card_free(card);
+
+	usb_free_all_descriptors(f);
+}
+
+struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
+{
+	struct f_midi *midi;
+	struct f_midi_opts *opts;
+	int status, i;
+
+	opts = container_of(fi, struct f_midi_opts, func_inst);
+	/* sanity check */
+	if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS)
+		return ERR_PTR(-EINVAL);
+
+	/* allocate and initialize one new instance */
+	midi = kzalloc(sizeof(*midi), GFP_KERNEL);
+	if (!midi)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < opts->in_ports; i++) {
+		struct gmidi_in_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
+
+		if (!port) {
+			status = -ENOMEM;
+			goto setup_fail;
+		}
+
+		port->midi = midi;
+		port->active = 0;
+		port->cable = i;
+		midi->in_port[i] = port;
+	}
+
+	/* set up ALSA midi devices */
+	midi->id = kstrdup(opts->id, GFP_KERNEL);
+	if (opts->id && !midi->id) {
+		status = -ENOMEM;
+		goto kstrdup_fail;
+	}
+	midi->in_ports = opts->in_ports;
+	midi->out_ports = opts->out_ports;
+	midi->index = opts->index;
+	midi->buflen = opts->buflen;
+	midi->qlen = opts->qlen;
+
+	midi->func.name		= "gmidi function";
+	midi->func.strings	= midi_strings;
+	midi->func.bind		= f_midi_bind;
+	midi->func.unbind	= f_midi_unbind;
+	midi->func.set_alt	= f_midi_set_alt;
+	midi->func.disable	= f_midi_disable;
+	midi->func.free_func	= f_midi_free;
+
+	return &midi->func;
+
+kstrdup_fail:
+	f_midi_unregister_card(midi);
+setup_fail:
+	for (--i; i >= 0; i--)
+		kfree(midi->in_port[i]);
+	kfree(midi);
+	return ERR_PTR(status);
+}
+
+DECLARE_USB_FUNCTION_INIT(midi, f_midi_alloc_inst, f_midi_alloc);
+#endif

drivers/usb/gadget/function/u_midi.h

+/*
+ * u_midi.h
+ *
+ * Utility definitions for the midi function
+ *
+ * Copyright (c) 2014 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_MIDI_H
+#define U_MIDI_H
+
+#include <linux/usb/composite.h>
+
+struct f_midi_opts {
+	struct usb_function_instance	func_inst;
+	int				index;
+	char				*id;
+	unsigned int			in_ports;
+	unsigned int			out_ports;
+	unsigned int			buflen;
+	unsigned int			qlen;
+};
+
+#endif /* U_MIDI_H */
+

drivers/usb/gadget/legacy/gmidi.c

@@ -37,6 +37,7 @@
 
 #include "gadget_chips.h"
 
+#define USBF_MIDI_INCLUDED
 #include "f_midi.c"
 
 /*-------------------------------------------------------------------------*/