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