linux/sound/oss/sys_timer.c
<<
>>
Prefs
   1/*
   2 * sound/oss/sys_timer.c
   3 *
   4 * The default timer for the Level 2 sequencer interface
   5 * Uses the (1/HZ sec) timer of kernel.
   6 */
   7/*
   8 * Copyright (C) by Hannu Savolainen 1993-1997
   9 *
  10 * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
  11 * Version 2 (June 1991). See the "COPYING" file distributed with this software
  12 * for more info.
  13 */
  14/*
  15 * Thomas Sailer   : ioctl code reworked (vmalloc/vfree removed)
  16 * Andrew Veliath  : adapted tmr2ticks from level 1 sequencer (avoid overflow)
  17 */
  18#include <linux/spinlock.h>
  19#include "sound_config.h"
  20
  21static volatile int opened, tmr_running;
  22static volatile unsigned int tmr_offs, tmr_ctr;
  23static volatile unsigned long ticks_offs;
  24static volatile int curr_tempo, curr_timebase;
  25static volatile unsigned long curr_ticks;
  26static volatile unsigned long next_event_time;
  27static unsigned long prev_event_time;
  28
  29static void     poll_def_tmr(unsigned long dummy);
  30static DEFINE_SPINLOCK(lock);
  31static DEFINE_TIMER(def_tmr, poll_def_tmr, 0, 0);
  32
  33static unsigned long
  34tmr2ticks(int tmr_value)
  35{
  36        /*
  37         *    Convert timer ticks to MIDI ticks
  38         */
  39
  40        unsigned long tmp;
  41        unsigned long scale;
  42
  43        /* tmr_value (ticks per sec) *
  44           1000000 (usecs per sec) / HZ (ticks per sec) -=> usecs */
  45        tmp = tmr_value * (1000000 / HZ);
  46        scale = (60 * 1000000) / (curr_tempo * curr_timebase);  /* usecs per MIDI tick */
  47        return (tmp + scale / 2) / scale;
  48}
  49
  50static void
  51poll_def_tmr(unsigned long dummy)
  52{
  53        if (!opened)
  54                return;
  55        def_tmr.expires = (1) + jiffies;
  56        add_timer(&def_tmr);
  57
  58        if (!tmr_running)
  59                return;
  60
  61        spin_lock(&lock);
  62        tmr_ctr++;
  63        curr_ticks = ticks_offs + tmr2ticks(tmr_ctr);
  64
  65        if (curr_ticks >= next_event_time) {
  66                next_event_time = (unsigned long) -1;
  67                sequencer_timer(0);
  68        }
  69
  70        spin_unlock(&lock);
  71}
  72
  73static void
  74tmr_reset(void)
  75{
  76        unsigned long   flags;
  77
  78        spin_lock_irqsave(&lock,flags);
  79        tmr_offs = 0;
  80        ticks_offs = 0;
  81        tmr_ctr = 0;
  82        next_event_time = (unsigned long) -1;
  83        prev_event_time = 0;
  84        curr_ticks = 0;
  85        spin_unlock_irqrestore(&lock,flags);
  86}
  87
  88static int
  89def_tmr_open(int dev, int mode)
  90{
  91        if (opened)
  92                return -EBUSY;
  93
  94        tmr_reset();
  95        curr_tempo = 60;
  96        curr_timebase = 100;
  97        opened = 1;
  98        {
  99                def_tmr.expires = (1) + jiffies;
 100                add_timer(&def_tmr);
 101        }
 102
 103        return 0;
 104}
 105
 106static void
 107def_tmr_close(int dev)
 108{
 109        opened = tmr_running = 0;
 110        del_timer(&def_tmr);
 111}
 112
 113static int
 114def_tmr_event(int dev, unsigned char *event)
 115{
 116        unsigned char   cmd = event[1];
 117        unsigned long   parm = *(int *) &event[4];
 118
 119        switch (cmd)
 120          {
 121          case TMR_WAIT_REL:
 122                  parm += prev_event_time;
 123          case TMR_WAIT_ABS:
 124                  if (parm > 0)
 125                    {
 126                            long            time;
 127
 128                            if (parm <= curr_ticks)     /* It's the time */
 129                                    return TIMER_NOT_ARMED;
 130
 131                            time = parm;
 132                            next_event_time = prev_event_time = time;
 133
 134                            return TIMER_ARMED;
 135                    }
 136                  break;
 137
 138          case TMR_START:
 139                  tmr_reset();
 140                  tmr_running = 1;
 141                  break;
 142
 143          case TMR_STOP:
 144                  tmr_running = 0;
 145                  break;
 146
 147          case TMR_CONTINUE:
 148                  tmr_running = 1;
 149                  break;
 150
 151          case TMR_TEMPO:
 152                  if (parm)
 153                    {
 154                            if (parm < 8)
 155                                    parm = 8;
 156                            if (parm > 360)
 157                                    parm = 360;
 158                            tmr_offs = tmr_ctr;
 159                            ticks_offs += tmr2ticks(tmr_ctr);
 160                            tmr_ctr = 0;
 161                            curr_tempo = parm;
 162                    }
 163                  break;
 164
 165          case TMR_ECHO:
 166                  seq_copy_to_input(event, 8);
 167                  break;
 168
 169          default:;
 170          }
 171
 172        return TIMER_NOT_ARMED;
 173}
 174
 175static unsigned long
 176def_tmr_get_time(int dev)
 177{
 178        if (!opened)
 179                return 0;
 180
 181        return curr_ticks;
 182}
 183
 184/* same as sound_timer.c:timer_ioctl!? */
 185static int def_tmr_ioctl(int dev, unsigned int cmd, void __user *arg)
 186{
 187        int __user *p = arg;
 188        int val;
 189
 190        switch (cmd) {
 191        case SNDCTL_TMR_SOURCE:
 192                return __put_user(TMR_INTERNAL, p);
 193
 194        case SNDCTL_TMR_START:
 195                tmr_reset();
 196                tmr_running = 1;
 197                return 0;
 198
 199        case SNDCTL_TMR_STOP:
 200                tmr_running = 0;
 201                return 0;
 202
 203        case SNDCTL_TMR_CONTINUE:
 204                tmr_running = 1;
 205                return 0;
 206
 207        case SNDCTL_TMR_TIMEBASE:
 208                if (__get_user(val, p))
 209                        return -EFAULT;
 210                if (val) {
 211                        if (val < 1)
 212                                val = 1;
 213                        if (val > 1000)
 214                                val = 1000;
 215                        curr_timebase = val;
 216                }
 217                return __put_user(curr_timebase, p);
 218
 219        case SNDCTL_TMR_TEMPO:
 220                if (__get_user(val, p))
 221                        return -EFAULT;
 222                if (val) {
 223                        if (val < 8)
 224                                val = 8;
 225                        if (val > 250)
 226                                val = 250;
 227                        tmr_offs = tmr_ctr;
 228                        ticks_offs += tmr2ticks(tmr_ctr);
 229                        tmr_ctr = 0;
 230                        curr_tempo = val;
 231                        reprogram_timer();
 232                }
 233                return __put_user(curr_tempo, p);
 234
 235        case SNDCTL_SEQ_CTRLRATE:
 236                if (__get_user(val, p))
 237                        return -EFAULT;
 238                if (val != 0)   /* Can't change */
 239                        return -EINVAL;
 240                val = ((curr_tempo * curr_timebase) + 30) / 60;
 241                return __put_user(val, p);
 242                
 243        case SNDCTL_SEQ_GETTIME:
 244                return __put_user(curr_ticks, p);
 245                
 246        case SNDCTL_TMR_METRONOME:
 247                /* NOP */
 248                break;
 249                
 250        default:;
 251        }
 252        return -EINVAL;
 253}
 254
 255static void
 256def_tmr_arm(int dev, long time)
 257{
 258        if (time < 0)
 259                time = curr_ticks + 1;
 260        else if (time <= curr_ticks)    /* It's the time */
 261                return;
 262
 263        next_event_time = prev_event_time = time;
 264
 265        return;
 266}
 267
 268struct sound_timer_operations default_sound_timer =
 269{
 270        .owner          = THIS_MODULE,
 271        .info           = {"System clock", 0},
 272        .priority       = 0,    /* Priority */
 273        .devlink        = 0,    /* Local device link */
 274        .open           = def_tmr_open,
 275        .close          = def_tmr_close,
 276        .event          = def_tmr_event,
 277        .get_time       = def_tmr_get_time,
 278        .ioctl          = def_tmr_ioctl,
 279        .arm_timer      = def_tmr_arm
 280};
 281