sound/usb/line6/midi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Line 6 Linux USB driver
   4  *
   5  * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
   6  */
   7
   8 #include <linux/slab.h>
   9 #include <linux/usb.h>
  10 #include <linux/export.h>
  11 #include <sound/core.h>
  12 #include <sound/rawmidi.h>
  13
  14 #include "driver.h"
  15 #include "midi.h"
  16
  17 #define line6_rawmidi_substream_midi(substream) \
  18         ((struct snd_line6_midi *)((substream)->rmidi->private_data))
  19
  20 static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
  21                            int length);
  22
  23 /*
  24         Pass data received via USB to MIDI.
  25 */
  26 void line6_midi_receive(struct usb_line6 *line6, unsigned char *data,
  27                         int length)
  28 {
  29         if (line6->line6midi->substream_receive)
  30                 snd_rawmidi_receive(line6->line6midi->substream_receive,
  31                                     data, length);
  32 }
  33
  34 /*
  35         Read data from MIDI buffer and transmit them via USB.
  36 */
  37 static void line6_midi_transmit(struct snd_rawmidi_substream *substream)
  38 {
  39         struct usb_line6 *line6 =
  40             line6_rawmidi_substream_midi(substream)->line6;
  41         struct snd_line6_midi *line6midi = line6->line6midi;
  42         struct midi_buffer *mb = &line6midi->midibuf_out;
  43         unsigned char chunk[LINE6_FALLBACK_MAXPACKETSIZE];
  44         int req, done;
  45
  46         for (;;) {
  47                 req = min(line6_midibuf_bytes_free(mb), line6->max_packet_size);
  48                 done = snd_rawmidi_transmit_peek(substream, chunk, req);
  49
  50                 if (done == 0)
  51                         break;
  52
  53                 line6_midibuf_write(mb, chunk, done);
  54                 snd_rawmidi_transmit_ack(substream, done);
  55         }
  56
  57         for (;;) {
  58                 done = line6_midibuf_read(mb, chunk,
  59                                           LINE6_FALLBACK_MAXPACKETSIZE,
  60                                           LINE6_MIDIBUF_READ_TX);
  61
  62                 if (done == 0)
  63                         break;
  64
  65                 send_midi_async(line6, chunk, done);
  66         }
  67 }
  68
  69 /*
  70         Notification of completion of MIDI transmission.
  71 */
  72 static void midi_sent(struct urb *urb)
  73 {
  74         unsigned long flags;
  75         int status;
  76         int num;
  77         struct usb_line6 *line6 = (struct usb_line6 *)urb->context;
  78
  79         status = urb->status;
  80         kfree(urb->transfer_buffer);
  81         usb_free_urb(urb);
  82
  83         if (status == -ESHUTDOWN)
  84                 return;
  85
  86         spin_lock_irqsave(&line6->line6midi->lock, flags);
  87         num = --line6->line6midi->num_active_send_urbs;
  88
  89         if (num == 0) {
  90                 line6_midi_transmit(line6->line6midi->substream_transmit);
  91                 num = line6->line6midi->num_active_send_urbs;
  92         }
  93
  94         if (num == 0)
  95                 wake_up(&line6->line6midi->send_wait);
  96
  97         spin_unlock_irqrestore(&line6->line6midi->lock, flags);
  98 }
  99
 100 /*
 101         Send an asynchronous MIDI message.
 102         Assumes that line6->line6midi->lock is held
 103         (i.e., this function is serialized).
 104 */
 105 static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
 106                            int length)
 107 {
 108         struct urb *urb;
 109         int retval;
 110         unsigned char *transfer_buffer;
 111
 112         urb = usb_alloc_urb(0, GFP_ATOMIC);
 113
 114         if (urb == NULL)
 115                 return -ENOMEM;
 116
 117         transfer_buffer = kmemdup(data, length, GFP_ATOMIC);
 118
 119         if (transfer_buffer == NULL) {
 120                 usb_free_urb(urb);
 121                 return -ENOMEM;
 122         }
 123
 124         usb_fill_int_urb(urb, line6->usbdev,
 125                          usb_sndintpipe(line6->usbdev,
 126                                          line6->properties->ep_ctrl_w),
 127                          transfer_buffer, length, midi_sent, line6,
 128                          line6->interval);
 129         urb->actual_length = 0;
 130         retval = usb_urb_ep_type_check(urb);
 131         if (retval < 0)
 132                 goto error;
 133
 134         retval = usb_submit_urb(urb, GFP_ATOMIC);
 135         if (retval < 0)
 136                 goto error;
 137
 138         ++line6->line6midi->num_active_send_urbs;
 139         return 0;
 140
 141  error:
 142         dev_err(line6->ifcdev, "usb_submit_urb failed\n");
 143         usb_free_urb(urb);
 144         return retval;
 145 }
 146
 147 static int line6_midi_output_open(struct snd_rawmidi_substream *substream)
 148 {
 149         return 0;
 150 }
 151
 152 static int line6_midi_output_close(struct snd_rawmidi_substream *substream)
 153 {
 154         return 0;
 155 }
 156
 157 static void line6_midi_output_trigger(struct snd_rawmidi_substream *substream,
 158                                       int up)
 159 {
 160         unsigned long flags;
 161         struct usb_line6 *line6 =
 162             line6_rawmidi_substream_midi(substream)->line6;
 163
 164         line6->line6midi->substream_transmit = substream;
 165         spin_lock_irqsave(&line6->line6midi->lock, flags);
 166
 167         if (line6->line6midi->num_active_send_urbs == 0)
 168                 line6_midi_transmit(substream);
 169
 170         spin_unlock_irqrestore(&line6->line6midi->lock, flags);
 171 }
 172
 173 static void line6_midi_output_drain(struct snd_rawmidi_substream *substream)
 174 {
 175         struct usb_line6 *line6 =
 176             line6_rawmidi_substream_midi(substream)->line6;
 177         struct snd_line6_midi *midi = line6->line6midi;
 178
 179         wait_event_interruptible(midi->send_wait,
 180                                  midi->num_active_send_urbs == 0);
 181 }
 182
 183 static int line6_midi_input_open(struct snd_rawmidi_substream *substream)
 184 {
 185         return 0;
 186 }
 187
 188 static int line6_midi_input_close(struct snd_rawmidi_substream *substream)
 189 {
 190         return 0;
 191 }
 192
 193 static void line6_midi_input_trigger(struct snd_rawmidi_substream *substream,
 194                                      int up)
 195 {
 196         struct usb_line6 *line6 =
 197             line6_rawmidi_substream_midi(substream)->line6;
 198
 199         if (up)
 200                 line6->line6midi->substream_receive = substream;
 201         else
 202                 line6->line6midi->substream_receive = NULL;
 203 }
 204
 205 static const struct snd_rawmidi_ops line6_midi_output_ops = {
 206         .open = line6_midi_output_open,
 207         .close = line6_midi_output_close,
 208         .trigger = line6_midi_output_trigger,
 209         .drain = line6_midi_output_drain,
 210 };
 211
 212 static const struct snd_rawmidi_ops line6_midi_input_ops = {
 213         .open = line6_midi_input_open,
 214         .close = line6_midi_input_close,
 215         .trigger = line6_midi_input_trigger,
 216 };
 217
 218 /* Create a MIDI device */
 219 static int snd_line6_new_midi(struct usb_line6 *line6,
 220                               struct snd_rawmidi **rmidi_ret)
 221 {
 222         struct snd_rawmidi *rmidi;
 223         int err;
 224
 225         err = snd_rawmidi_new(line6->card, "Line 6 MIDI", 0, 1, 1, rmidi_ret);
 226         if (err < 0)
 227                 return err;
 228
 229         rmidi = *rmidi_ret;
 230         strcpy(rmidi->id, line6->properties->id);
 231         strcpy(rmidi->name, line6->properties->name);
 232
 233         rmidi->info_flags =
 234             SNDRV_RAWMIDI_INFO_OUTPUT |
 235             SNDRV_RAWMIDI_INFO_INPUT | SNDRV_RAWMIDI_INFO_DUPLEX;
 236
 237         snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
 238                             &line6_midi_output_ops);
 239         snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
 240                             &line6_midi_input_ops);
 241         return 0;
 242 }
 243
 244 /* MIDI device destructor */
 245 static void snd_line6_midi_free(struct snd_rawmidi *rmidi)
 246 {
 247         struct snd_line6_midi *line6midi = rmidi->private_data;
 248
 249         line6_midibuf_destroy(&line6midi->midibuf_in);
 250         line6_midibuf_destroy(&line6midi->midibuf_out);
 251         kfree(line6midi);
 252 }
 253
 254 /*
 255         Initialize the Line 6 MIDI subsystem.
 256 */
 257 int line6_init_midi(struct usb_line6 *line6)
 258 {
 259         int err;
 260         struct snd_rawmidi *rmidi;
 261         struct snd_line6_midi *line6midi;
 262
 263         if (!(line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI)) {
 264                 /* skip MIDI initialization and report success */
 265                 return 0;
 266         }
 267
 268         err = snd_line6_new_midi(line6, &rmidi);
 269         if (err < 0)
 270                 return err;
 271
 272         line6midi = kzalloc(sizeof(struct snd_line6_midi), GFP_KERNEL);
 273         if (!line6midi)
 274                 return -ENOMEM;
 275
 276         rmidi->private_data = line6midi;
 277         rmidi->private_free = snd_line6_midi_free;
 278
 279         init_waitqueue_head(&line6midi->send_wait);
 280         spin_lock_init(&line6midi->lock);
 281         line6midi->line6 = line6;
 282
 283         err = line6_midibuf_init(&line6midi->midibuf_in, MIDI_BUFFER_SIZE, 0);
 284         if (err < 0)
 285                 return err;
 286
 287         err = line6_midibuf_init(&line6midi->midibuf_out, MIDI_BUFFER_SIZE, 1);
 288         if (err < 0)
 289                 return err;
 290
 291         line6->line6midi = line6midi;
 292         return 0;
 293 }
 294 EXPORT_SYMBOL_GPL(line6_init_midi);