Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / usb / gadget / function / f_midi.c
diff --git a/kernel/drivers/usb/gadget/function/f_midi.c b/kernel/drivers/usb/gadget/function/f_midi.c
new file mode 100644 (file)
index 0000000..6316aa5
--- /dev/null
@@ -0,0 +1,1176 @@
+/*
+ * f_midi.c -- USB MIDI class function driver
+ *
+ * Copyright (C) 2006 Thumtronics Pty Ltd.
+ * Developed for Thumtronics by Grey Innovation
+ * Ben Williamson <ben.williamson@greyinnovation.com>
+ *
+ * Rewritten for the composite framework
+ *   Copyright (C) 2011 Daniel Mack <zonque@gmail.com>
+ *
+ * Based on drivers/usb/gadget/f_audio.c,
+ *   Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
+ *   Copyright (C) 2008 Analog Devices, Inc
+ *
+ * and drivers/usb/gadget/midi.c,
+ *   Copyright (C) 2006 Thumtronics Pty Ltd.
+ *   Ben Williamson <ben.williamson@greyinnovation.com>
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/rawmidi.h>
+
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/midi.h>
+
+#include "u_f.h"
+#include "u_midi.h"
+
+MODULE_AUTHOR("Ben Williamson");
+MODULE_LICENSE("GPL v2");
+
+static const char f_midi_shortname[] = "f_midi";
+static const char f_midi_longname[] = "MIDI Gadget";
+
+/*
+ * We can only handle 16 cables on one single endpoint, as cable numbers are
+ * stored in 4-bit fields. And as the interface currently only holds one
+ * single endpoint, this is the maximum number of ports we can allow.
+ */
+#define MAX_PORTS 16
+
+/*
+ * This is a gadget, and the IN/OUT naming is from the host's perspective.
+ * USB -> OUT endpoint -> rawmidi
+ * USB <- IN endpoint  <- rawmidi
+ */
+struct gmidi_in_port {
+       struct f_midi *midi;
+       int active;
+       uint8_t cable;
+       uint8_t state;
+#define STATE_UNKNOWN  0
+#define STATE_1PARAM   1
+#define STATE_2PARAM_1 2
+#define STATE_2PARAM_2 3
+#define STATE_SYSEX_0  4
+#define STATE_SYSEX_1  5
+#define STATE_SYSEX_2  6
+       uint8_t data[2];
+};
+
+struct f_midi {
+       struct usb_function     func;
+       struct usb_gadget       *gadget;
+       struct usb_ep           *in_ep, *out_ep;
+       struct snd_card         *card;
+       struct snd_rawmidi      *rmidi;
+
+       struct snd_rawmidi_substream *in_substream[MAX_PORTS];
+       struct snd_rawmidi_substream *out_substream[MAX_PORTS];
+       struct gmidi_in_port    *in_port[MAX_PORTS];
+
+       unsigned long           out_triggered;
+       struct tasklet_struct   tasklet;
+       unsigned int in_ports;
+       unsigned int out_ports;
+       int index;
+       char *id;
+       unsigned int buflen, qlen;
+};
+
+static inline struct f_midi *func_to_midi(struct usb_function *f)
+{
+       return container_of(f, struct f_midi, func);
+}
+
+static void f_midi_transmit(struct f_midi *midi, struct usb_request *req);
+
+DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
+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 = {
+       .bLength =              USB_DT_INTERFACE_SIZE,
+       .bDescriptorType =      USB_DT_INTERFACE,
+       /* .bInterfaceNumber =  DYNAMIC */
+       /* .bNumEndpoints =     DYNAMIC */
+       .bInterfaceClass =      USB_CLASS_AUDIO,
+       .bInterfaceSubClass =   USB_SUBCLASS_AUDIOCONTROL,
+       /* .iInterface =        DYNAMIC */
+};
+
+/* B.3.2  Class-Specific AC Interface Descriptor */
+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,
+       .bcdADC =               cpu_to_le16(0x0100),
+       .wTotalLength =         cpu_to_le16(UAC_DT_AC_HEADER_SIZE(1)),
+       .bInCollection =        1,
+       /* .baInterfaceNr =     DYNAMIC */
+};
+
+/* B.4.1  Standard MS Interface Descriptor */
+static struct usb_interface_descriptor ms_interface_desc = {
+       .bLength =              USB_DT_INTERFACE_SIZE,
+       .bDescriptorType =      USB_DT_INTERFACE,
+       /* .bInterfaceNumber =  DYNAMIC */
+       .bNumEndpoints =        2,
+       .bInterfaceClass =      USB_CLASS_AUDIO,
+       .bInterfaceSubClass =   USB_SUBCLASS_MIDISTREAMING,
+       /* .iInterface =        DYNAMIC */
+};
+
+/* B.4.2  Class-Specific MS Interface Descriptor */
+static struct usb_ms_header_descriptor ms_header_desc = {
+       .bLength =              USB_DT_MS_HEADER_SIZE,
+       .bDescriptorType =      USB_DT_CS_INTERFACE,
+       .bDescriptorSubtype =   USB_MS_HEADER,
+       .bcdMSC =               cpu_to_le16(0x0100),
+       /* .wTotalLength =      DYNAMIC */
+};
+
+/* B.5.1  Standard Bulk OUT Endpoint Descriptor */
+static struct usb_endpoint_descriptor bulk_out_desc = {
+       .bLength =              USB_DT_ENDPOINT_AUDIO_SIZE,
+       .bDescriptorType =      USB_DT_ENDPOINT,
+       .bEndpointAddress =     USB_DIR_OUT,
+       .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+};
+
+/* B.5.2  Class-specific MS Bulk OUT Endpoint Descriptor */
+static struct usb_ms_endpoint_descriptor_16 ms_out_desc = {
+       /* .bLength =           DYNAMIC */
+       .bDescriptorType =      USB_DT_CS_ENDPOINT,
+       .bDescriptorSubtype =   USB_MS_GENERAL,
+       /* .bNumEmbMIDIJack =   DYNAMIC */
+       /* .baAssocJackID =     DYNAMIC */
+};
+
+/* B.6.1  Standard Bulk IN Endpoint Descriptor */
+static struct usb_endpoint_descriptor bulk_in_desc = {
+       .bLength =              USB_DT_ENDPOINT_AUDIO_SIZE,
+       .bDescriptorType =      USB_DT_ENDPOINT,
+       .bEndpointAddress =     USB_DIR_IN,
+       .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+};
+
+/* B.6.2  Class-specific MS Bulk IN Endpoint Descriptor */
+static struct usb_ms_endpoint_descriptor_16 ms_in_desc = {
+       /* .bLength =           DYNAMIC */
+       .bDescriptorType =      USB_DT_CS_ENDPOINT,
+       .bDescriptorSubtype =   USB_MS_GENERAL,
+       /* .bNumEmbMIDIJack =   DYNAMIC */
+       /* .baAssocJackID =     DYNAMIC */
+};
+
+/* string IDs are assigned dynamically */
+
+#define STRING_FUNC_IDX                        0
+
+static struct usb_string midi_string_defs[] = {
+       [STRING_FUNC_IDX].s = "MIDI function",
+       {  } /* end of list */
+};
+
+static struct usb_gadget_strings midi_stringtab = {
+       .language       = 0x0409,       /* en-us */
+       .strings        = midi_string_defs,
+};
+
+static struct usb_gadget_strings *midi_strings[] = {
+       &midi_stringtab,
+       NULL,
+};
+
+static inline struct usb_request *midi_alloc_ep_req(struct usb_ep *ep,
+                                                   unsigned length)
+{
+       return alloc_ep_req(ep, length, length);
+}
+
+static void free_ep_req(struct usb_ep *ep, struct usb_request *req)
+{
+       kfree(req->buf);
+       usb_ep_free_request(ep, req);
+}
+
+static const uint8_t f_midi_cin_length[] = {
+       0, 0, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1
+};
+
+/*
+ * Receives a chunk of MIDI data.
+ */
+static void f_midi_read_data(struct usb_ep *ep, int cable,
+                            uint8_t *data, int length)
+{
+       struct f_midi *midi = ep->driver_data;
+       struct snd_rawmidi_substream *substream = midi->out_substream[cable];
+
+       if (!substream)
+               /* Nobody is listening - throw it on the floor. */
+               return;
+
+       if (!test_bit(cable, &midi->out_triggered))
+               return;
+
+       snd_rawmidi_receive(substream, data, length);
+}
+
+static void f_midi_handle_out_data(struct usb_ep *ep, struct usb_request *req)
+{
+       unsigned int i;
+       u8 *buf = req->buf;
+
+       for (i = 0; i + 3 < req->actual; i += 4)
+               if (buf[i] != 0) {
+                       int cable = buf[i] >> 4;
+                       int length = f_midi_cin_length[buf[i] & 0x0f];
+                       f_midi_read_data(ep, cable, &buf[i + 1], length);
+               }
+}
+
+static void
+f_midi_complete(struct usb_ep *ep, struct usb_request *req)
+{
+       struct f_midi *midi = ep->driver_data;
+       struct usb_composite_dev *cdev = midi->func.config->cdev;
+       int status = req->status;
+
+       switch (status) {
+       case 0:                  /* normal completion */
+               if (ep == midi->out_ep) {
+                       /* We received stuff. req is queued again, below */
+                       f_midi_handle_out_data(ep, req);
+               } else if (ep == midi->in_ep) {
+                       /* Our transmit completed. See if there's more to go.
+                        * f_midi_transmit eats req, don't queue it again. */
+                       f_midi_transmit(midi, req);
+                       return;
+               }
+               break;
+
+       /* this endpoint is normally active while we're configured */
+       case -ECONNABORTED:     /* hardware forced ep reset */
+       case -ECONNRESET:       /* request dequeued */
+       case -ESHUTDOWN:        /* disconnect from host */
+               VDBG(cdev, "%s gone (%d), %d/%d\n", ep->name, status,
+                               req->actual, req->length);
+               if (ep == midi->out_ep)
+                       f_midi_handle_out_data(ep, req);
+
+               free_ep_req(ep, req);
+               return;
+
+       case -EOVERFLOW:        /* buffer overrun on read means that
+                                * we didn't provide a big enough buffer.
+                                */
+       default:
+               DBG(cdev, "%s complete --> %d, %d/%d\n", ep->name,
+                               status, req->actual, req->length);
+               break;
+       case -EREMOTEIO:        /* short read */
+               break;
+       }
+
+       status = usb_ep_queue(ep, req, GFP_ATOMIC);
+       if (status) {
+               ERROR(cdev, "kill %s:  resubmit %d bytes --> %d\n",
+                               ep->name, req->length, status);
+               usb_ep_set_halt(ep);
+               /* FIXME recover later ... somehow */
+       }
+}
+
+static int f_midi_start_ep(struct f_midi *midi,
+                          struct usb_function *f,
+                          struct usb_ep *ep)
+{
+       int err;
+       struct usb_composite_dev *cdev = f->config->cdev;
+
+       if (ep->driver_data)
+               usb_ep_disable(ep);
+
+       err = config_ep_by_speed(midi->gadget, f, ep);
+       if (err) {
+               ERROR(cdev, "can't configure %s: %d\n", ep->name, err);
+               return err;
+       }
+
+       err = usb_ep_enable(ep);
+       if (err) {
+               ERROR(cdev, "can't start %s: %d\n", ep->name, err);
+               return err;
+       }
+
+       ep->driver_data = midi;
+
+       return 0;
+}
+
+static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+       struct f_midi *midi = func_to_midi(f);
+       struct usb_composite_dev *cdev = f->config->cdev;
+       unsigned i;
+       int err;
+
+       err = f_midi_start_ep(midi, f, midi->in_ep);
+       if (err)
+               return err;
+
+       err = f_midi_start_ep(midi, f, midi->out_ep);
+       if (err)
+               return err;
+
+       if (midi->out_ep->driver_data)
+               usb_ep_disable(midi->out_ep);
+
+       err = config_ep_by_speed(midi->gadget, f, midi->out_ep);
+       if (err) {
+               ERROR(cdev, "can't configure %s: %d\n",
+                     midi->out_ep->name, err);
+               return err;
+       }
+
+       err = usb_ep_enable(midi->out_ep);
+       if (err) {
+               ERROR(cdev, "can't start %s: %d\n",
+                     midi->out_ep->name, err);
+               return err;
+       }
+
+       midi->out_ep->driver_data = midi;
+
+       /* allocate a bunch of read buffers and queue them all at once. */
+       for (i = 0; i < midi->qlen && err == 0; i++) {
+               struct usb_request *req =
+                       midi_alloc_ep_req(midi->out_ep, midi->buflen);
+               if (req == NULL)
+                       return -ENOMEM;
+
+               req->complete = f_midi_complete;
+               err = usb_ep_queue(midi->out_ep, req, GFP_ATOMIC);
+               if (err) {
+                       ERROR(midi, "%s queue req: %d\n",
+                                   midi->out_ep->name, err);
+               }
+       }
+
+       return 0;
+}
+
+static void f_midi_disable(struct usb_function *f)
+{
+       struct f_midi *midi = func_to_midi(f);
+       struct usb_composite_dev *cdev = f->config->cdev;
+
+       DBG(cdev, "disable\n");
+
+       /*
+        * just disable endpoints, forcing completion of pending i/o.
+        * all our completion handlers free their requests in this case.
+        */
+       usb_ep_disable(midi->in_ep);
+       usb_ep_disable(midi->out_ep);
+}
+
+static int f_midi_snd_free(struct snd_device *device)
+{
+       return 0;
+}
+
+static void f_midi_transmit_packet(struct usb_request *req, uint8_t p0,
+                                       uint8_t p1, uint8_t p2, uint8_t p3)
+{
+       unsigned length = req->length;
+       u8 *buf = (u8 *)req->buf + length;
+
+       buf[0] = p0;
+       buf[1] = p1;
+       buf[2] = p2;
+       buf[3] = p3;
+       req->length = length + 4;
+}
+
+/*
+ * Converts MIDI commands to USB MIDI packets.
+ */
+static void f_midi_transmit_byte(struct usb_request *req,
+                                struct gmidi_in_port *port, uint8_t b)
+{
+       uint8_t p0 = port->cable << 4;
+
+       if (b >= 0xf8) {
+               f_midi_transmit_packet(req, p0 | 0x0f, b, 0, 0);
+       } else if (b >= 0xf0) {
+               switch (b) {
+               case 0xf0:
+                       port->data[0] = b;
+                       port->state = STATE_SYSEX_1;
+                       break;
+               case 0xf1:
+               case 0xf3:
+                       port->data[0] = b;
+                       port->state = STATE_1PARAM;
+                       break;
+               case 0xf2:
+                       port->data[0] = b;
+                       port->state = STATE_2PARAM_1;
+                       break;
+               case 0xf4:
+               case 0xf5:
+                       port->state = STATE_UNKNOWN;
+                       break;
+               case 0xf6:
+                       f_midi_transmit_packet(req, p0 | 0x05, 0xf6, 0, 0);
+                       port->state = STATE_UNKNOWN;
+                       break;
+               case 0xf7:
+                       switch (port->state) {
+                       case STATE_SYSEX_0:
+                               f_midi_transmit_packet(req,
+                                       p0 | 0x05, 0xf7, 0, 0);
+                               break;
+                       case STATE_SYSEX_1:
+                               f_midi_transmit_packet(req,
+                                       p0 | 0x06, port->data[0], 0xf7, 0);
+                               break;
+                       case STATE_SYSEX_2:
+                               f_midi_transmit_packet(req,
+                                       p0 | 0x07, port->data[0],
+                                       port->data[1], 0xf7);
+                               break;
+                       }
+                       port->state = STATE_UNKNOWN;
+                       break;
+               }
+       } else if (b >= 0x80) {
+               port->data[0] = b;
+               if (b >= 0xc0 && b <= 0xdf)
+                       port->state = STATE_1PARAM;
+               else
+                       port->state = STATE_2PARAM_1;
+       } else { /* b < 0x80 */
+               switch (port->state) {
+               case STATE_1PARAM:
+                       if (port->data[0] < 0xf0) {
+                               p0 |= port->data[0] >> 4;
+                       } else {
+                               p0 |= 0x02;
+                               port->state = STATE_UNKNOWN;
+                       }
+                       f_midi_transmit_packet(req, p0, port->data[0], b, 0);
+                       break;
+               case STATE_2PARAM_1:
+                       port->data[1] = b;
+                       port->state = STATE_2PARAM_2;
+                       break;
+               case STATE_2PARAM_2:
+                       if (port->data[0] < 0xf0) {
+                               p0 |= port->data[0] >> 4;
+                               port->state = STATE_2PARAM_1;
+                       } else {
+                               p0 |= 0x03;
+                               port->state = STATE_UNKNOWN;
+                       }
+                       f_midi_transmit_packet(req,
+                               p0, port->data[0], port->data[1], b);
+                       break;
+               case STATE_SYSEX_0:
+                       port->data[0] = b;
+                       port->state = STATE_SYSEX_1;
+                       break;
+               case STATE_SYSEX_1:
+                       port->data[1] = b;
+                       port->state = STATE_SYSEX_2;
+                       break;
+               case STATE_SYSEX_2:
+                       f_midi_transmit_packet(req,
+                               p0 | 0x04, port->data[0], port->data[1], b);
+                       port->state = STATE_SYSEX_0;
+                       break;
+               }
+       }
+}
+
+static void f_midi_transmit(struct f_midi *midi, struct usb_request *req)
+{
+       struct usb_ep *ep = midi->in_ep;
+       int i;
+
+       if (!ep)
+               return;
+
+       if (!req)
+               req = midi_alloc_ep_req(ep, midi->buflen);
+
+       if (!req) {
+               ERROR(midi, "%s: alloc_ep_request failed\n", __func__);
+               return;
+       }
+       req->length = 0;
+       req->complete = f_midi_complete;
+
+       for (i = 0; i < MAX_PORTS; i++) {
+               struct gmidi_in_port *port = midi->in_port[i];
+               struct snd_rawmidi_substream *substream = midi->in_substream[i];
+
+               if (!port || !port->active || !substream)
+                       continue;
+
+               while (req->length + 3 < midi->buflen) {
+                       uint8_t b;
+                       if (snd_rawmidi_transmit(substream, &b, 1) != 1) {
+                               port->active = 0;
+                               break;
+                       }
+                       f_midi_transmit_byte(req, port, b);
+               }
+       }
+
+       if (req->length > 0)
+               usb_ep_queue(ep, req, GFP_ATOMIC);
+       else
+               free_ep_req(ep, req);
+}
+
+static void f_midi_in_tasklet(unsigned long data)
+{
+       struct f_midi *midi = (struct f_midi *) data;
+       f_midi_transmit(midi, NULL);
+}
+
+static int f_midi_in_open(struct snd_rawmidi_substream *substream)
+{
+       struct f_midi *midi = substream->rmidi->private_data;
+
+       if (!midi->in_port[substream->number])
+               return -EINVAL;
+
+       VDBG(midi, "%s()\n", __func__);
+       midi->in_substream[substream->number] = substream;
+       midi->in_port[substream->number]->state = STATE_UNKNOWN;
+       return 0;
+}
+
+static int f_midi_in_close(struct snd_rawmidi_substream *substream)
+{
+       struct f_midi *midi = substream->rmidi->private_data;
+
+       VDBG(midi, "%s()\n", __func__);
+       return 0;
+}
+
+static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+       struct f_midi *midi = substream->rmidi->private_data;
+
+       if (!midi->in_port[substream->number])
+               return;
+
+       VDBG(midi, "%s() %d\n", __func__, up);
+       midi->in_port[substream->number]->active = up;
+       if (up)
+               tasklet_hi_schedule(&midi->tasklet);
+}
+
+static int f_midi_out_open(struct snd_rawmidi_substream *substream)
+{
+       struct f_midi *midi = substream->rmidi->private_data;
+
+       if (substream->number >= MAX_PORTS)
+               return -EINVAL;
+
+       VDBG(midi, "%s()\n", __func__);
+       midi->out_substream[substream->number] = substream;
+       return 0;
+}
+
+static int f_midi_out_close(struct snd_rawmidi_substream *substream)
+{
+       struct f_midi *midi = substream->rmidi->private_data;
+
+       VDBG(midi, "%s()\n", __func__);
+       return 0;
+}
+
+static void f_midi_out_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+       struct f_midi *midi = substream->rmidi->private_data;
+
+       VDBG(midi, "%s()\n", __func__);
+
+       if (up)
+               set_bit(substream->number, &midi->out_triggered);
+       else
+               clear_bit(substream->number, &midi->out_triggered);
+}
+
+static struct snd_rawmidi_ops gmidi_in_ops = {
+       .open = f_midi_in_open,
+       .close = f_midi_in_close,
+       .trigger = f_midi_in_trigger,
+};
+
+static struct snd_rawmidi_ops gmidi_out_ops = {
+       .open = f_midi_out_open,
+       .close = f_midi_out_close,
+       .trigger = f_midi_out_trigger
+};
+
+static inline void f_midi_unregister_card(struct f_midi *midi)
+{
+       if (midi->card) {
+               snd_card_free(midi->card);
+               midi->card = NULL;
+       }
+}
+
+/* register as a sound "card" */
+static int f_midi_register_card(struct f_midi *midi)
+{
+       struct snd_card *card;
+       struct snd_rawmidi *rmidi;
+       int err;
+       static struct snd_device_ops ops = {
+               .dev_free = f_midi_snd_free,
+       };
+
+       err = snd_card_new(&midi->gadget->dev, midi->index, midi->id,
+                          THIS_MODULE, 0, &card);
+       if (err < 0) {
+               ERROR(midi, "snd_card_new() failed\n");
+               goto fail;
+       }
+       midi->card = card;
+
+       err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, midi, &ops);
+       if (err < 0) {
+               ERROR(midi, "snd_device_new() failed: error %d\n", err);
+               goto fail;
+       }
+
+       strcpy(card->driver, f_midi_longname);
+       strcpy(card->longname, f_midi_longname);
+       strcpy(card->shortname, f_midi_shortname);
+
+       /* Set up rawmidi */
+       snd_component_add(card, "MIDI");
+       err = snd_rawmidi_new(card, card->longname, 0,
+                             midi->out_ports, midi->in_ports, &rmidi);
+       if (err < 0) {
+               ERROR(midi, "snd_rawmidi_new() failed: error %d\n", err);
+               goto fail;
+       }
+       midi->rmidi = rmidi;
+       strcpy(rmidi->name, card->shortname);
+       rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
+                           SNDRV_RAWMIDI_INFO_INPUT |
+                           SNDRV_RAWMIDI_INFO_DUPLEX;
+       rmidi->private_data = midi;
+
+       /*
+        * Yes, rawmidi OUTPUT = USB IN, and rawmidi INPUT = USB OUT.
+        * It's an upside-down world being a gadget.
+        */
+       snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &gmidi_in_ops);
+       snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &gmidi_out_ops);
+
+       /* register it - we're ready to go */
+       err = snd_card_register(card);
+       if (err < 0) {
+               ERROR(midi, "snd_card_register() failed\n");
+               goto fail;
+       }
+
+       VDBG(midi, "%s() finished ok\n", __func__);
+       return 0;
+
+fail:
+       f_midi_unregister_card(midi);
+       return err;
+}
+
+/* MIDI function driver setup/binding */
+
+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];
+       struct usb_midi_in_jack_descriptor jack_in_emb_desc[MAX_PORTS];
+       struct usb_midi_out_jack_descriptor_1 jack_out_ext_desc[MAX_PORTS];
+       struct usb_midi_out_jack_descriptor_1 jack_out_emb_desc[MAX_PORTS];
+       struct usb_composite_dev *cdev = c->cdev;
+       struct f_midi *midi = func_to_midi(f);
+       struct usb_string *us;
+       int status, n, jack = 1, i = 0;
+
+       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;
+
+       /* maybe allocate device-global string ID */
+       us = usb_gstrings_attach(c->cdev, midi_strings,
+                                ARRAY_SIZE(midi_string_defs));
+       if (IS_ERR(us)) {
+               status = PTR_ERR(us);
+               goto fail;
+       }
+       ac_interface_desc.iInterface = us[STRING_FUNC_IDX].id;
+
+       /* We have two interfaces, AudioControl and MIDIStreaming */
+       status = usb_interface_id(c, f);
+       if (status < 0)
+               goto fail;
+       ac_interface_desc.bInterfaceNumber = status;
+
+       status = usb_interface_id(c, f);
+       if (status < 0)
+               goto fail;
+       ms_interface_desc.bInterfaceNumber = status;
+       ac_header_desc.baInterfaceNr[0] = status;
+
+       status = -ENODEV;
+
+       /* allocate instance-specific endpoints */
+       midi->in_ep = usb_ep_autoconfig(cdev->gadget, &bulk_in_desc);
+       if (!midi->in_ep)
+               goto fail;
+       midi->in_ep->driver_data = cdev;        /* claim */
+
+       midi->out_ep = usb_ep_autoconfig(cdev->gadget, &bulk_out_desc);
+       if (!midi->out_ep)
+               goto fail;
+       midi->out_ep->driver_data = cdev;       /* claim */
+
+       /* allocate temporary function list */
+       midi_function = kcalloc((MAX_PORTS * 4) + 9, sizeof(*midi_function),
+                               GFP_KERNEL);
+       if (!midi_function) {
+               status = -ENOMEM;
+               goto fail;
+       }
+
+       /*
+        * construct the function's descriptor set. As the number of
+        * input and output MIDI ports is configurable, we have to do
+        * it that way.
+        */
+
+       /* add the headers - these are always the same */
+       midi_function[i++] = (struct usb_descriptor_header *) &ac_interface_desc;
+       midi_function[i++] = (struct usb_descriptor_header *) &ac_header_desc;
+       midi_function[i++] = (struct usb_descriptor_header *) &ms_interface_desc;
+
+       /* calculate the header's wTotalLength */
+       n = USB_DT_MS_HEADER_SIZE
+               + (midi->in_ports + midi->out_ports) *
+                       (USB_DT_MIDI_IN_SIZE + USB_DT_MIDI_OUT_SIZE(1));
+       ms_header_desc.wTotalLength = cpu_to_le16(n);
+
+       midi_function[i++] = (struct usb_descriptor_header *) &ms_header_desc;
+
+       /* configure the external IN jacks, each linked to an embedded OUT jack */
+       for (n = 0; n < midi->in_ports; n++) {
+               struct usb_midi_in_jack_descriptor *in_ext = &jack_in_ext_desc[n];
+               struct usb_midi_out_jack_descriptor_1 *out_emb = &jack_out_emb_desc[n];
+
+               in_ext->bLength                 = USB_DT_MIDI_IN_SIZE;
+               in_ext->bDescriptorType         = USB_DT_CS_INTERFACE;
+               in_ext->bDescriptorSubtype      = USB_MS_MIDI_IN_JACK;
+               in_ext->bJackType               = USB_MS_EXTERNAL;
+               in_ext->bJackID                 = jack++;
+               in_ext->iJack                   = 0;
+               midi_function[i++] = (struct usb_descriptor_header *) in_ext;
+
+               out_emb->bLength                = USB_DT_MIDI_OUT_SIZE(1);
+               out_emb->bDescriptorType        = USB_DT_CS_INTERFACE;
+               out_emb->bDescriptorSubtype     = USB_MS_MIDI_OUT_JACK;
+               out_emb->bJackType              = USB_MS_EMBEDDED;
+               out_emb->bJackID                = jack++;
+               out_emb->bNrInputPins           = 1;
+               out_emb->pins[0].baSourcePin    = 1;
+               out_emb->pins[0].baSourceID     = in_ext->bJackID;
+               out_emb->iJack                  = 0;
+               midi_function[i++] = (struct usb_descriptor_header *) out_emb;
+
+               /* link it to the endpoint */
+               ms_in_desc.baAssocJackID[n] = out_emb->bJackID;
+       }
+
+       /* configure the external OUT jacks, each linked to an embedded IN jack */
+       for (n = 0; n < midi->out_ports; n++) {
+               struct usb_midi_in_jack_descriptor *in_emb = &jack_in_emb_desc[n];
+               struct usb_midi_out_jack_descriptor_1 *out_ext = &jack_out_ext_desc[n];
+
+               in_emb->bLength                 = USB_DT_MIDI_IN_SIZE;
+               in_emb->bDescriptorType         = USB_DT_CS_INTERFACE;
+               in_emb->bDescriptorSubtype      = USB_MS_MIDI_IN_JACK;
+               in_emb->bJackType               = USB_MS_EMBEDDED;
+               in_emb->bJackID                 = jack++;
+               in_emb->iJack                   = 0;
+               midi_function[i++] = (struct usb_descriptor_header *) in_emb;
+
+               out_ext->bLength =              USB_DT_MIDI_OUT_SIZE(1);
+               out_ext->bDescriptorType =      USB_DT_CS_INTERFACE;
+               out_ext->bDescriptorSubtype =   USB_MS_MIDI_OUT_JACK;
+               out_ext->bJackType =            USB_MS_EXTERNAL;
+               out_ext->bJackID =              jack++;
+               out_ext->bNrInputPins =         1;
+               out_ext->iJack =                0;
+               out_ext->pins[0].baSourceID =   in_emb->bJackID;
+               out_ext->pins[0].baSourcePin =  1;
+               midi_function[i++] = (struct usb_descriptor_header *) out_ext;
+
+               /* link it to the endpoint */
+               ms_out_desc.baAssocJackID[n] = in_emb->bJackID;
+       }
+
+       /* configure the endpoint descriptors ... */
+       ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
+       ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
+
+       ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
+       ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
+
+       /* ... and add them to the list */
+       midi_function[i++] = (struct usb_descriptor_header *) &bulk_out_desc;
+       midi_function[i++] = (struct usb_descriptor_header *) &ms_out_desc;
+       midi_function[i++] = (struct usb_descriptor_header *) &bulk_in_desc;
+       midi_function[i++] = (struct usb_descriptor_header *) &ms_in_desc;
+       midi_function[i++] = NULL;
+
+       /*
+        * support all relevant hardware speeds... we expect that when
+        * hardware is dual speed, all bulk-capable endpoints work at
+        * both speeds
+        */
+       /* copy descriptors, and track endpoint copies */
+       f->fs_descriptors = usb_copy_descriptors(midi_function);
+       if (!f->fs_descriptors)
+               goto fail_f_midi;
+
+       if (gadget_is_dualspeed(c->cdev->gadget)) {
+               bulk_in_desc.wMaxPacketSize = cpu_to_le16(512);
+               bulk_out_desc.wMaxPacketSize = cpu_to_le16(512);
+               f->hs_descriptors = usb_copy_descriptors(midi_function);
+               if (!f->hs_descriptors)
+                       goto fail_f_midi;
+       }
+
+       kfree(midi_function);
+
+       return 0;
+
+fail_f_midi:
+       kfree(midi_function);
+       usb_free_descriptors(f->hs_descriptors);
+fail:
+       f_midi_unregister_card(midi);
+fail_register:
+       /* we might as well release our claims on endpoints */
+       if (midi->out_ep)
+               midi->out_ep->driver_data = NULL;
+       if (midi->in_ep)
+               midi->in_ep->driver_data = NULL;
+
+       ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
+
+       return status;
+}
+
+static inline struct f_midi_opts *to_f_midi_opts(struct config_item *item)
+{
+       return container_of(to_config_group(item), struct f_midi_opts,
+                           func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_midi_opts);
+CONFIGFS_ATTR_OPS(f_midi_opts);
+
+static void midi_attr_release(struct config_item *item)
+{
+       struct f_midi_opts *opts = to_f_midi_opts(item);
+
+       usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations midi_item_ops = {
+       .release        = midi_attr_release,
+       .show_attribute = f_midi_opts_attr_show,
+       .store_attribute = f_midi_opts_attr_store,
+};
+
+#define F_MIDI_OPT(name, test_limit, limit)                            \
+static ssize_t f_midi_opts_##name##_show(struct f_midi_opts *opts, char *page) \
+{                                                                      \
+       int result;                                                     \
+                                                                       \
+       mutex_lock(&opts->lock);                                        \
+       result = sprintf(page, "%d\n", opts->name);                     \
+       mutex_unlock(&opts->lock);                                      \
+                                                                       \
+       return result;                                                  \
+}                                                                      \
+                                                                       \
+static ssize_t f_midi_opts_##name##_store(struct f_midi_opts *opts,    \
+                                        const char *page, size_t len)  \
+{                                                                      \
+       int ret;                                                        \
+       u32 num;                                                        \
+                                                                       \
+       mutex_lock(&opts->lock);                                        \
+       if (opts->refcnt) {                                             \
+               ret = -EBUSY;                                           \
+               goto end;                                               \
+       }                                                               \
+                                                                       \
+       ret = kstrtou32(page, 0, &num);                                 \
+       if (ret)                                                        \
+               goto end;                                               \
+                                                                       \
+       if (test_limit && num > limit) {                                \
+               ret = -EINVAL;                                          \
+               goto end;                                               \
+       }                                                               \
+       opts->name = num;                                               \
+       ret = len;                                                      \
+                                                                       \
+end:                                                                   \
+       mutex_unlock(&opts->lock);                                      \
+       return ret;                                                     \
+}                                                                      \
+                                                                       \
+static struct f_midi_opts_attribute f_midi_opts_##name =               \
+       __CONFIGFS_ATTR(name, S_IRUGO | S_IWUSR, f_midi_opts_##name##_show, \
+                       f_midi_opts_##name##_store)
+
+F_MIDI_OPT(index, true, SNDRV_CARDS);
+F_MIDI_OPT(buflen, false, 0);
+F_MIDI_OPT(qlen, false, 0);
+F_MIDI_OPT(in_ports, true, MAX_PORTS);
+F_MIDI_OPT(out_ports, true, MAX_PORTS);
+
+static ssize_t f_midi_opts_id_show(struct f_midi_opts *opts, char *page)
+{
+       int result;
+
+       mutex_lock(&opts->lock);
+       if (opts->id) {
+               result = strlcpy(page, opts->id, PAGE_SIZE);
+       } else {
+               page[0] = 0;
+               result = 0;
+       }
+
+       mutex_unlock(&opts->lock);
+
+       return result;
+}
+
+static ssize_t f_midi_opts_id_store(struct f_midi_opts *opts,
+                                   const char *page, size_t len)
+{
+       int ret;
+       char *c;
+
+       mutex_lock(&opts->lock);
+       if (opts->refcnt) {
+               ret = -EBUSY;
+               goto end;
+       }
+
+       c = kstrndup(page, len, GFP_KERNEL);
+       if (!c) {
+               ret = -ENOMEM;
+               goto end;
+       }
+       if (opts->id_allocated)
+               kfree(opts->id);
+       opts->id = c;
+       opts->id_allocated = true;
+       ret = len;
+end:
+       mutex_unlock(&opts->lock);
+       return ret;
+}
+
+static struct f_midi_opts_attribute f_midi_opts_id =
+       __CONFIGFS_ATTR(id, S_IRUGO | S_IWUSR, f_midi_opts_id_show,
+                       f_midi_opts_id_store);
+
+static struct configfs_attribute *midi_attrs[] = {
+       &f_midi_opts_index.attr,
+       &f_midi_opts_buflen.attr,
+       &f_midi_opts_qlen.attr,
+       &f_midi_opts_in_ports.attr,
+       &f_midi_opts_out_ports.attr,
+       &f_midi_opts_id.attr,
+       NULL,
+};
+
+static struct config_item_type midi_func_type = {
+       .ct_item_ops    = &midi_item_ops,
+       .ct_attrs       = midi_attrs,
+       .ct_owner       = THIS_MODULE,
+};
+
+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);
+
+       if (opts->id_allocated)
+               kfree(opts->id);
+
+       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);
+
+       mutex_init(&opts->lock);
+       opts->func_inst.free_func_inst = f_midi_free_inst;
+       opts->index = SNDRV_DEFAULT_IDX1;
+       opts->id = SNDRV_DEFAULT_STR1;
+       opts->buflen = 256;
+       opts->qlen = 32;
+       opts->in_ports = 1;
+       opts->out_ports = 1;
+
+       config_group_init_type_name(&opts->func_inst.group, "",
+                                   &midi_func_type);
+
+       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);
+       mutex_lock(&opts->lock);
+       for (i = opts->in_ports - 1; i >= 0; --i)
+               kfree(midi->in_port[i]);
+       kfree(midi);
+       --opts->refcnt;
+       mutex_unlock(&opts->lock);
+}
+
+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);
+}
+
+static 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);
+
+       mutex_lock(&opts->lock);
+       /* sanity check */
+       if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
+               mutex_unlock(&opts->lock);
+               return ERR_PTR(-EINVAL);
+       }
+
+       /* allocate and initialize one new instance */
+       midi = kzalloc(sizeof(*midi), GFP_KERNEL);
+       if (!midi) {
+               mutex_unlock(&opts->lock);
+               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;
+                       mutex_unlock(&opts->lock);
+                       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;
+               mutex_unlock(&opts->lock);
+               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;
+       ++opts->refcnt;
+       mutex_unlock(&opts->lock);
+
+       midi->func.name         = "gmidi function";
+       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);