sound/oss/midibuf.c

   1 /*
   2  * sound/oss/midibuf.c
   3  *
   4  * Device file manager for /dev/midi#
   5  */
   6 /*
   7  * Copyright (C) by Hannu Savolainen 1993-1997
   8  *
   9  * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
  10  * Version 2 (June 1991). See the "COPYING" file distributed with this software
  11  * for more info.
  12  */
  13 /*
  14  * Thomas Sailer   : ioctl code reworked (vmalloc/vfree removed)
  15  */
  16 #include <linux/stddef.h>
  17 #include <linux/kmod.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/sched/signal.h>
  20
  21 #define MIDIBUF_C
  22
  23 #include "sound_config.h"
  24
  25
  26 /*
  27  * Don't make MAX_QUEUE_SIZE larger than 4000
  28  */
  29
  30 #define MAX_QUEUE_SIZE  4000
  31
  32 static wait_queue_head_t midi_sleeper[MAX_MIDI_DEV];
  33 static wait_queue_head_t input_sleeper[MAX_MIDI_DEV];
  34
  35 struct midi_buf
  36 {
  37         int len, head, tail;
  38         unsigned char queue[MAX_QUEUE_SIZE];
  39 };
  40
  41 struct midi_parms
  42 {
  43         long prech_timeout;     /*
  44                                  * Timeout before the first ch
  45                                  */
  46 };
  47
  48 static struct midi_buf *midi_out_buf[MAX_MIDI_DEV] = {NULL};
  49 static struct midi_buf *midi_in_buf[MAX_MIDI_DEV] = {NULL};
  50 static struct midi_parms parms[MAX_MIDI_DEV];
  51
  52 static void midi_poll(unsigned long dummy);
  53
  54
  55 static DEFINE_TIMER(poll_timer, midi_poll, 0, 0);
  56
  57 static volatile int open_devs;
  58 static DEFINE_SPINLOCK(lock);
  59
  60 #define DATA_AVAIL(q) (q->len)
  61 #define SPACE_AVAIL(q) (MAX_QUEUE_SIZE - q->len)
  62
  63 #define QUEUE_BYTE(q, data) \
  64         if (SPACE_AVAIL(q)) \
  65         { \
  66           unsigned long flags; \
  67           spin_lock_irqsave(&lock, flags); \
  68           q->queue[q->tail] = (data); \
  69           q->len++; q->tail = (q->tail+1) % MAX_QUEUE_SIZE; \
  70           spin_unlock_irqrestore(&lock, flags); \
  71         }
  72
  73 #define REMOVE_BYTE(q, data) \
  74         if (DATA_AVAIL(q)) \
  75         { \
  76           unsigned long flags; \
  77           spin_lock_irqsave(&lock, flags); \
  78           data = q->queue[q->head]; \
  79           q->len--; q->head = (q->head+1) % MAX_QUEUE_SIZE; \
  80           spin_unlock_irqrestore(&lock, flags); \
  81         }
  82
  83 static void drain_midi_queue(int dev)
  84 {
  85
  86         /*
  87          * Give the Midi driver time to drain its output queues
  88          */
  89
  90         if (midi_devs[dev]->buffer_status != NULL)
  91                 wait_event_interruptible_timeout(midi_sleeper[dev],
  92                                 !midi_devs[dev]->buffer_status(dev), HZ/10);
  93 }
  94
  95 static void midi_input_intr(int dev, unsigned char data)
  96 {
  97         if (midi_in_buf[dev] == NULL)
  98                 return;
  99
 100         if (data == 0xfe)       /*
 101                                  * Active sensing
 102                                  */
 103                 return;         /*
 104                                  * Ignore
 105                                  */
 106
 107         if (SPACE_AVAIL(midi_in_buf[dev])) {
 108                 QUEUE_BYTE(midi_in_buf[dev], data);
 109                 wake_up(&input_sleeper[dev]);
 110         }
 111 }
 112
 113 static void midi_output_intr(int dev)
 114 {
 115         /*
 116          * Currently NOP
 117          */
 118 }
 119
 120 static void midi_poll(unsigned long dummy)
 121 {
 122         unsigned long   flags;
 123         int             dev;
 124
 125         spin_lock_irqsave(&lock, flags);
 126         if (open_devs)
 127         {
 128                 for (dev = 0; dev < num_midis; dev++)
 129                         if (midi_devs[dev] != NULL && midi_out_buf[dev] != NULL)
 130                         {
 131                                 while (DATA_AVAIL(midi_out_buf[dev]))
 132                                 {
 133                                         int ok;
 134                                         int c = midi_out_buf[dev]->queue[midi_out_buf[dev]->head];
 135
 136                                         spin_unlock_irqrestore(&lock,flags);/* Give some time to others */
 137                                         ok = midi_devs[dev]->outputc(dev, c);
 138                                         spin_lock_irqsave(&lock, flags);
 139                                         if (!ok)
 140                                                 break;
 141                                         midi_out_buf[dev]->head = (midi_out_buf[dev]->head + 1) % MAX_QUEUE_SIZE;
 142                                         midi_out_buf[dev]->len--;
 143                                 }
 144
 145                                 if (DATA_AVAIL(midi_out_buf[dev]) < 100)
 146                                         wake_up(&midi_sleeper[dev]);
 147                         }
 148                 poll_timer.expires = (1) + jiffies;
 149                 add_timer(&poll_timer);
 150                 /*
 151                  * Come back later
 152                  */
 153         }
 154         spin_unlock_irqrestore(&lock, flags);
 155 }
 156
 157 int MIDIbuf_open(int dev, struct file *file)
 158 {
 159         int mode, err;
 160
 161         dev = dev >> 4;
 162         mode = translate_mode(file);
 163
 164         if (num_midis > MAX_MIDI_DEV)
 165         {
 166                 printk(KERN_ERR "midi: Too many midi interfaces\n");
 167                 num_midis = MAX_MIDI_DEV;
 168         }
 169         if (dev < 0 || dev >= num_midis || midi_devs[dev] == NULL)
 170                   return -ENXIO;
 171         /*
 172          *    Interrupts disabled. Be careful
 173          */
 174
 175         module_put(midi_devs[dev]->owner);
 176
 177         if ((err = midi_devs[dev]->open(dev, mode,
 178                                  midi_input_intr, midi_output_intr)) < 0)
 179                 return err;
 180
 181         parms[dev].prech_timeout = MAX_SCHEDULE_TIMEOUT;
 182         midi_in_buf[dev] = vmalloc(sizeof(struct midi_buf));
 183
 184         if (midi_in_buf[dev] == NULL)
 185         {
 186                 printk(KERN_WARNING "midi: Can't allocate buffer\n");
 187                 midi_devs[dev]->close(dev);
 188                 return -EIO;
 189         }
 190         midi_in_buf[dev]->len = midi_in_buf[dev]->head = midi_in_buf[dev]->tail = 0;
 191
 192         midi_out_buf[dev] = vmalloc(sizeof(struct midi_buf));
 193
 194         if (midi_out_buf[dev] == NULL)
 195         {
 196                 printk(KERN_WARNING "midi: Can't allocate buffer\n");
 197                 midi_devs[dev]->close(dev);
 198                 vfree(midi_in_buf[dev]);
 199                 midi_in_buf[dev] = NULL;
 200                 return -EIO;
 201         }
 202         midi_out_buf[dev]->len = midi_out_buf[dev]->head = midi_out_buf[dev]->tail = 0;
 203         open_devs++;
 204
 205         init_waitqueue_head(&midi_sleeper[dev]);
 206         init_waitqueue_head(&input_sleeper[dev]);
 207
 208         if (open_devs < 2)      /* This was first open */
 209         {
 210                 poll_timer.expires = 1 + jiffies;
 211                 add_timer(&poll_timer); /* Start polling */
 212         }
 213         return err;
 214 }
 215
 216 void MIDIbuf_release(int dev, struct file *file)
 217 {
 218         int mode;
 219
 220         dev = dev >> 4;
 221         mode = translate_mode(file);
 222
 223         if (dev < 0 || dev >= num_midis || midi_devs[dev] == NULL)
 224                 return;
 225
 226         /*
 227          * Wait until the queue is empty
 228          */
 229
 230         if (mode != OPEN_READ)
 231         {
 232                 midi_devs[dev]->outputc(dev, 0xfe);     /*
 233                                                            * Active sensing to shut the
 234                                                            * devices
 235                                                          */
 236
 237                 wait_event_interruptible(midi_sleeper[dev],
 238                                          !DATA_AVAIL(midi_out_buf[dev]));
 239                 /*
 240                  *      Sync
 241                  */
 242
 243                 drain_midi_queue(dev);  /*
 244                                          * Ensure the output queues are empty
 245                                          */
 246         }
 247
 248         midi_devs[dev]->close(dev);
 249
 250         open_devs--;
 251         if (open_devs == 0)
 252                 del_timer_sync(&poll_timer);
 253         vfree(midi_in_buf[dev]);
 254         vfree(midi_out_buf[dev]);
 255         midi_in_buf[dev] = NULL;
 256         midi_out_buf[dev] = NULL;
 257
 258         module_put(midi_devs[dev]->owner);
 259 }
 260
 261 int MIDIbuf_write(int dev, struct file *file, const char __user *buf, int count)
 262 {
 263         int c, n, i;
 264         unsigned char tmp_data;
 265
 266         dev = dev >> 4;
 267
 268         if (!count)
 269                 return 0;
 270
 271         c = 0;
 272
 273         while (c < count)
 274         {
 275                 n = SPACE_AVAIL(midi_out_buf[dev]);
 276
 277                 if (n == 0) {   /*
 278                                  * No space just now.
 279                                  */
 280
 281                         if (file->f_flags & O_NONBLOCK) {
 282                                 c = -EAGAIN;
 283                                 goto out;
 284                         }
 285
 286                         if (wait_event_interruptible(midi_sleeper[dev],
 287                                                 SPACE_AVAIL(midi_out_buf[dev])))
 288                         {
 289                                 c = -EINTR;
 290                                 goto out;
 291                         }
 292                         n = SPACE_AVAIL(midi_out_buf[dev]);
 293                 }
 294                 if (n > (count - c))
 295                         n = count - c;
 296
 297                 for (i = 0; i < n; i++)
 298                 {
 299                         /* BROKE BROKE BROKE - CAN'T DO THIS WITH CLI !! */
 300                         /* yes, think the same, so I removed the cli() brackets
 301                                 QUEUE_BYTE is protected against interrupts */
 302                         if (copy_from_user((char *) &tmp_data, &(buf)[c], 1)) {
 303                                 c = -EFAULT;
 304                                 goto out;
 305                         }
 306                         QUEUE_BYTE(midi_out_buf[dev], tmp_data);
 307                         c++;
 308                 }
 309         }
 310 out:
 311         return c;
 312 }
 313
 314
 315 int MIDIbuf_read(int dev, struct file *file, char __user *buf, int count)
 316 {
 317         int n, c = 0;
 318         unsigned char tmp_data;
 319
 320         dev = dev >> 4;
 321
 322         if (!DATA_AVAIL(midi_in_buf[dev])) {    /*
 323                                                  * No data yet, wait
 324                                                  */
 325                 if (file->f_flags & O_NONBLOCK) {
 326                         c = -EAGAIN;
 327                         goto out;
 328                 }
 329                 wait_event_interruptible_timeout(input_sleeper[dev],
 330                                                  DATA_AVAIL(midi_in_buf[dev]),
 331                                                  parms[dev].prech_timeout);
 332
 333                 if (signal_pending(current))
 334                         c = -EINTR;     /* The user is getting restless */
 335         }
 336         if (c == 0 && DATA_AVAIL(midi_in_buf[dev]))     /*
 337                                                          * Got some bytes
 338                                                          */
 339         {
 340                 n = DATA_AVAIL(midi_in_buf[dev]);
 341                 if (n > count)
 342                         n = count;
 343                 c = 0;
 344
 345                 while (c < n)
 346                 {
 347                         char *fixit;
 348                         REMOVE_BYTE(midi_in_buf[dev], tmp_data);
 349                         fixit = (char *) &tmp_data;
 350                         /* BROKE BROKE BROKE */
 351                         /* yes removed the cli() brackets again
 352                          should q->len,tail&head be atomic_t? */
 353                         if (copy_to_user(&(buf)[c], fixit, 1)) {
 354                                 c = -EFAULT;
 355                                 goto out;
 356                         }
 357                         c++;
 358                 }
 359         }
 360 out:
 361         return c;
 362 }
 363
 364 int MIDIbuf_ioctl(int dev, struct file *file,
 365                   unsigned int cmd, void __user *arg)
 366 {
 367         int val;
 368
 369         dev = dev >> 4;
 370
 371         if (((cmd >> 8) & 0xff) == 'C')
 372         {
 373                 if (midi_devs[dev]->coproc)     /* Coprocessor ioctl */
 374                         return midi_devs[dev]->coproc->ioctl(midi_devs[dev]->coproc->devc, cmd, arg, 0);
 375 /*              printk("/dev/midi%d: No coprocessor for this device\n", dev);*/
 376                 return -ENXIO;
 377         }
 378         else
 379         {
 380                 switch (cmd)
 381                 {
 382                         case SNDCTL_MIDI_PRETIME:
 383                                 if (get_user(val, (int __user *)arg))
 384                                         return -EFAULT;
 385                                 if (val < 0)
 386                                         val = 0;
 387                                 val = (HZ * val) / 10;
 388                                 parms[dev].prech_timeout = val;
 389                                 return put_user(val, (int __user *)arg);
 390
 391                         default:
 392                                 if (!midi_devs[dev]->ioctl)
 393                                         return -EINVAL;
 394                                 return midi_devs[dev]->ioctl(dev, cmd, arg);
 395                 }
 396         }
 397 }
 398
 399 /* No kernel lock - fine */
 400 unsigned int MIDIbuf_poll(int dev, struct file *file, poll_table * wait)
 401 {
 402         unsigned int mask = 0;
 403
 404         dev = dev >> 4;
 405
 406         /* input */
 407         poll_wait(file, &input_sleeper[dev], wait);
 408         if (DATA_AVAIL(midi_in_buf[dev]))
 409                 mask |= POLLIN | POLLRDNORM;
 410
 411         /* output */
 412         poll_wait(file, &midi_sleeper[dev], wait);
 413         if (!SPACE_AVAIL(midi_out_buf[dev]))
 414                 mask |= POLLOUT | POLLWRNORM;
 415
 416         return mask;
 417 }
 418
 419
 420 int MIDIbuf_avail(int dev)
 421 {
 422         if (midi_in_buf[dev])
 423                 return DATA_AVAIL (midi_in_buf[dev]);
 424         return 0;
 425 }
 426 EXPORT_SYMBOL(MIDIbuf_avail);
 427