ALSA: sound: Move dereference after NULL test and drop unnecessary NULL tests
[linux-2.6.git] / sound / drivers / dummy.c
1 /*
2  *  Dummy soundcard
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *
5  *   This program is free software; you can redistribute it and/or modify
6  *   it under the terms of the GNU General Public License as published by
7  *   the Free Software Foundation; either version 2 of the License, or
8  *   (at your option) any later version.
9  *
10  *   This program is distributed in the hope that it will be useful,
11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  *   GNU General Public License for more details.
14  *
15  *   You should have received a copy of the GNU General Public License
16  *   along with this program; if not, write to the Free Software
17  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
18  *
19  */
20
21 #include <linux/init.h>
22 #include <linux/err.h>
23 #include <linux/platform_device.h>
24 #include <linux/jiffies.h>
25 #include <linux/slab.h>
26 #include <linux/time.h>
27 #include <linux/wait.h>
28 #include <linux/hrtimer.h>
29 #include <linux/math64.h>
30 #include <linux/moduleparam.h>
31 #include <sound/core.h>
32 #include <sound/control.h>
33 #include <sound/tlv.h>
34 #include <sound/pcm.h>
35 #include <sound/rawmidi.h>
36 #include <sound/info.h>
37 #include <sound/initval.h>
38
39 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
40 MODULE_DESCRIPTION("Dummy soundcard (/dev/null)");
41 MODULE_LICENSE("GPL");
42 MODULE_SUPPORTED_DEVICE("{{ALSA,Dummy soundcard}}");
43
44 #define MAX_PCM_DEVICES         4
45 #define MAX_PCM_SUBSTREAMS      128
46 #define MAX_MIDI_DEVICES        2
47
48 #if 0 /* emu10k1 emulation */
49 #define MAX_BUFFER_SIZE         (128 * 1024)
50 static int emu10k1_playback_constraints(struct snd_pcm_runtime *runtime)
51 {
52         int err;
53         err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
54         if (err < 0)
55                 return err;
56         err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 256, UINT_MAX);
57         if (err < 0)
58                 return err;
59         return 0;
60 }
61 #define add_playback_constraints emu10k1_playback_constraints
62 #endif
63
64 #if 0 /* RME9652 emulation */
65 #define MAX_BUFFER_SIZE         (26 * 64 * 1024)
66 #define USE_FORMATS             SNDRV_PCM_FMTBIT_S32_LE
67 #define USE_CHANNELS_MIN        26
68 #define USE_CHANNELS_MAX        26
69 #define USE_PERIODS_MIN         2
70 #define USE_PERIODS_MAX         2
71 #endif
72
73 #if 0 /* ICE1712 emulation */
74 #define MAX_BUFFER_SIZE         (256 * 1024)
75 #define USE_FORMATS             SNDRV_PCM_FMTBIT_S32_LE
76 #define USE_CHANNELS_MIN        10
77 #define USE_CHANNELS_MAX        10
78 #define USE_PERIODS_MIN         1
79 #define USE_PERIODS_MAX         1024
80 #endif
81
82 #if 0 /* UDA1341 emulation */
83 #define MAX_BUFFER_SIZE         (16380)
84 #define USE_FORMATS             SNDRV_PCM_FMTBIT_S16_LE
85 #define USE_CHANNELS_MIN        2
86 #define USE_CHANNELS_MAX        2
87 #define USE_PERIODS_MIN         2
88 #define USE_PERIODS_MAX         255
89 #endif
90
91 #if 0 /* simple AC97 bridge (intel8x0) with 48kHz AC97 only codec */
92 #define USE_FORMATS             SNDRV_PCM_FMTBIT_S16_LE
93 #define USE_CHANNELS_MIN        2
94 #define USE_CHANNELS_MAX        2
95 #define USE_RATE                SNDRV_PCM_RATE_48000
96 #define USE_RATE_MIN            48000
97 #define USE_RATE_MAX            48000
98 #endif
99
100 #if 0 /* CA0106 */
101 #define USE_FORMATS             SNDRV_PCM_FMTBIT_S16_LE
102 #define USE_CHANNELS_MIN        2
103 #define USE_CHANNELS_MAX        2
104 #define USE_RATE                (SNDRV_PCM_RATE_48000|SNDRV_PCM_RATE_96000|SNDRV_PCM_RATE_192000) 
105 #define USE_RATE_MIN            48000 
106 #define USE_RATE_MAX            192000
107 #define MAX_BUFFER_SIZE         ((65536-64)*8)
108 #define MAX_PERIOD_SIZE         (65536-64)
109 #define USE_PERIODS_MIN         2
110 #define USE_PERIODS_MAX         8
111 #endif
112
113
114 /* defaults */
115 #ifndef MAX_BUFFER_SIZE
116 #define MAX_BUFFER_SIZE         (64*1024)
117 #endif
118 #ifndef MAX_PERIOD_SIZE
119 #define MAX_PERIOD_SIZE         MAX_BUFFER_SIZE
120 #endif
121 #ifndef USE_FORMATS
122 #define USE_FORMATS             (SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE)
123 #endif
124 #ifndef USE_RATE
125 #define USE_RATE                SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000
126 #define USE_RATE_MIN            5500
127 #define USE_RATE_MAX            48000
128 #endif
129 #ifndef USE_CHANNELS_MIN
130 #define USE_CHANNELS_MIN        1
131 #endif
132 #ifndef USE_CHANNELS_MAX
133 #define USE_CHANNELS_MAX        2
134 #endif
135 #ifndef USE_PERIODS_MIN
136 #define USE_PERIODS_MIN         1
137 #endif
138 #ifndef USE_PERIODS_MAX
139 #define USE_PERIODS_MAX         1024
140 #endif
141 #ifndef add_playback_constraints
142 #define add_playback_constraints(x) 0
143 #endif
144 #ifndef add_capture_constraints
145 #define add_capture_constraints(x) 0
146 #endif
147
148 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
149 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
150 static int enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
151 static int pcm_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
152 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
153 //static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 2};
154 #ifdef CONFIG_HIGH_RES_TIMERS
155 static int hrtimer = 1;
156 #endif
157 static int fake_buffer = 1;
158
159 module_param_array(index, int, NULL, 0444);
160 MODULE_PARM_DESC(index, "Index value for dummy soundcard.");
161 module_param_array(id, charp, NULL, 0444);
162 MODULE_PARM_DESC(id, "ID string for dummy soundcard.");
163 module_param_array(enable, bool, NULL, 0444);
164 MODULE_PARM_DESC(enable, "Enable this dummy soundcard.");
165 module_param_array(pcm_devs, int, NULL, 0444);
166 MODULE_PARM_DESC(pcm_devs, "PCM devices # (0-4) for dummy driver.");
167 module_param_array(pcm_substreams, int, NULL, 0444);
168 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-16) for dummy driver.");
169 //module_param_array(midi_devs, int, NULL, 0444);
170 //MODULE_PARM_DESC(midi_devs, "MIDI devices # (0-2) for dummy driver.");
171 module_param(fake_buffer, bool, 0444);
172 MODULE_PARM_DESC(fake_buffer, "Fake buffer allocations.");
173 #ifdef CONFIG_HIGH_RES_TIMERS
174 module_param(hrtimer, bool, 0644);
175 MODULE_PARM_DESC(hrtimer, "Use hrtimer as the timer source.");
176 #endif
177
178 static struct platform_device *devices[SNDRV_CARDS];
179
180 #define MIXER_ADDR_MASTER       0
181 #define MIXER_ADDR_LINE         1
182 #define MIXER_ADDR_MIC          2
183 #define MIXER_ADDR_SYNTH        3
184 #define MIXER_ADDR_CD           4
185 #define MIXER_ADDR_LAST         4
186
187 struct dummy_timer_ops {
188         int (*create)(struct snd_pcm_substream *);
189         void (*free)(struct snd_pcm_substream *);
190         int (*prepare)(struct snd_pcm_substream *);
191         int (*start)(struct snd_pcm_substream *);
192         int (*stop)(struct snd_pcm_substream *);
193         snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *);
194 };
195
196 struct snd_dummy {
197         struct snd_card *card;
198         struct snd_pcm *pcm;
199         spinlock_t mixer_lock;
200         int mixer_volume[MIXER_ADDR_LAST+1][2];
201         int capture_source[MIXER_ADDR_LAST+1][2];
202         const struct dummy_timer_ops *timer_ops;
203 };
204
205 /*
206  * system timer interface
207  */
208
209 struct dummy_systimer_pcm {
210         spinlock_t lock;
211         struct timer_list timer;
212         unsigned long base_time;
213         unsigned int frac_pos;  /* fractional sample position (based HZ) */
214         unsigned int frac_period_rest;
215         unsigned int frac_buffer_size;  /* buffer_size * HZ */
216         unsigned int frac_period_size;  /* period_size * HZ */
217         unsigned int rate;
218         int elapsed;
219         struct snd_pcm_substream *substream;
220 };
221
222 static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm)
223 {
224         dpcm->timer.expires = jiffies +
225                 (dpcm->frac_period_rest + dpcm->rate - 1) / dpcm->rate;
226         add_timer(&dpcm->timer);
227 }
228
229 static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm)
230 {
231         unsigned long delta;
232
233         delta = jiffies - dpcm->base_time;
234         if (!delta)
235                 return;
236         dpcm->base_time += delta;
237         delta *= dpcm->rate;
238         dpcm->frac_pos += delta;
239         while (dpcm->frac_pos >= dpcm->frac_buffer_size)
240                 dpcm->frac_pos -= dpcm->frac_buffer_size;
241         while (dpcm->frac_period_rest <= delta) {
242                 dpcm->elapsed++;
243                 dpcm->frac_period_rest += dpcm->frac_period_size;
244         }
245         dpcm->frac_period_rest -= delta;
246 }
247
248 static int dummy_systimer_start(struct snd_pcm_substream *substream)
249 {
250         struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
251         spin_lock(&dpcm->lock);
252         dpcm->base_time = jiffies;
253         dummy_systimer_rearm(dpcm);
254         spin_unlock(&dpcm->lock);
255         return 0;
256 }
257
258 static int dummy_systimer_stop(struct snd_pcm_substream *substream)
259 {
260         struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
261         spin_lock(&dpcm->lock);
262         del_timer(&dpcm->timer);
263         spin_unlock(&dpcm->lock);
264         return 0;
265 }
266
267 static int dummy_systimer_prepare(struct snd_pcm_substream *substream)
268 {
269         struct snd_pcm_runtime *runtime = substream->runtime;
270         struct dummy_systimer_pcm *dpcm = runtime->private_data;
271
272         dpcm->frac_pos = 0;
273         dpcm->rate = runtime->rate;
274         dpcm->frac_buffer_size = runtime->buffer_size * HZ;
275         dpcm->frac_period_size = runtime->period_size * HZ;
276         dpcm->frac_period_rest = dpcm->frac_period_size;
277         dpcm->elapsed = 0;
278
279         return 0;
280 }
281
282 static void dummy_systimer_callback(unsigned long data)
283 {
284         struct dummy_systimer_pcm *dpcm = (struct dummy_systimer_pcm *)data;
285         unsigned long flags;
286         int elapsed = 0;
287         
288         spin_lock_irqsave(&dpcm->lock, flags);
289         dummy_systimer_update(dpcm);
290         dummy_systimer_rearm(dpcm);
291         elapsed = dpcm->elapsed;
292         dpcm->elapsed = 0;
293         spin_unlock_irqrestore(&dpcm->lock, flags);
294         if (elapsed)
295                 snd_pcm_period_elapsed(dpcm->substream);
296 }
297
298 static snd_pcm_uframes_t
299 dummy_systimer_pointer(struct snd_pcm_substream *substream)
300 {
301         struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
302         snd_pcm_uframes_t pos;
303
304         spin_lock(&dpcm->lock);
305         dummy_systimer_update(dpcm);
306         pos = dpcm->frac_pos / HZ;
307         spin_unlock(&dpcm->lock);
308         return pos;
309 }
310
311 static int dummy_systimer_create(struct snd_pcm_substream *substream)
312 {
313         struct dummy_systimer_pcm *dpcm;
314
315         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
316         if (!dpcm)
317                 return -ENOMEM;
318         substream->runtime->private_data = dpcm;
319         init_timer(&dpcm->timer);
320         dpcm->timer.data = (unsigned long) dpcm;
321         dpcm->timer.function = dummy_systimer_callback;
322         spin_lock_init(&dpcm->lock);
323         dpcm->substream = substream;
324         return 0;
325 }
326
327 static void dummy_systimer_free(struct snd_pcm_substream *substream)
328 {
329         kfree(substream->runtime->private_data);
330 }
331
332 static struct dummy_timer_ops dummy_systimer_ops = {
333         .create =       dummy_systimer_create,
334         .free =         dummy_systimer_free,
335         .prepare =      dummy_systimer_prepare,
336         .start =        dummy_systimer_start,
337         .stop =         dummy_systimer_stop,
338         .pointer =      dummy_systimer_pointer,
339 };
340
341 #ifdef CONFIG_HIGH_RES_TIMERS
342 /*
343  * hrtimer interface
344  */
345
346 struct dummy_hrtimer_pcm {
347         ktime_t base_time;
348         ktime_t period_time;
349         atomic_t running;
350         struct hrtimer timer;
351         struct tasklet_struct tasklet;
352         struct snd_pcm_substream *substream;
353 };
354
355 static void dummy_hrtimer_pcm_elapsed(unsigned long priv)
356 {
357         struct dummy_hrtimer_pcm *dpcm = (struct dummy_hrtimer_pcm *)priv;
358         if (atomic_read(&dpcm->running))
359                 snd_pcm_period_elapsed(dpcm->substream);
360 }
361
362 static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
363 {
364         struct dummy_hrtimer_pcm *dpcm;
365
366         dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
367         if (!atomic_read(&dpcm->running))
368                 return HRTIMER_NORESTART;
369         tasklet_schedule(&dpcm->tasklet);
370         hrtimer_forward_now(timer, dpcm->period_time);
371         return HRTIMER_RESTART;
372 }
373
374 static int dummy_hrtimer_start(struct snd_pcm_substream *substream)
375 {
376         struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
377
378         dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
379         hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL);
380         atomic_set(&dpcm->running, 1);
381         return 0;
382 }
383
384 static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
385 {
386         struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
387
388         atomic_set(&dpcm->running, 0);
389         hrtimer_cancel(&dpcm->timer);
390         return 0;
391 }
392
393 static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
394 {
395         tasklet_kill(&dpcm->tasklet);
396 }
397
398 static snd_pcm_uframes_t
399 dummy_hrtimer_pointer(struct snd_pcm_substream *substream)
400 {
401         struct snd_pcm_runtime *runtime = substream->runtime;
402         struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
403         u64 delta;
404         u32 pos;
405
406         delta = ktime_us_delta(hrtimer_cb_get_time(&dpcm->timer),
407                                dpcm->base_time);
408         delta = div_u64(delta * runtime->rate + 999999, 1000000);
409         div_u64_rem(delta, runtime->buffer_size, &pos);
410         return pos;
411 }
412
413 static int dummy_hrtimer_prepare(struct snd_pcm_substream *substream)
414 {
415         struct snd_pcm_runtime *runtime = substream->runtime;
416         struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
417         unsigned int period, rate;
418         long sec;
419         unsigned long nsecs;
420
421         dummy_hrtimer_sync(dpcm);
422         period = runtime->period_size;
423         rate = runtime->rate;
424         sec = period / rate;
425         period %= rate;
426         nsecs = div_u64((u64)period * 1000000000UL + rate - 1, rate);
427         dpcm->period_time = ktime_set(sec, nsecs);
428
429         return 0;
430 }
431
432 static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
433 {
434         struct dummy_hrtimer_pcm *dpcm;
435
436         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
437         if (!dpcm)
438                 return -ENOMEM;
439         substream->runtime->private_data = dpcm;
440         hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
441         dpcm->timer.function = dummy_hrtimer_callback;
442         dpcm->substream = substream;
443         atomic_set(&dpcm->running, 0);
444         tasklet_init(&dpcm->tasklet, dummy_hrtimer_pcm_elapsed,
445                      (unsigned long)dpcm);
446         return 0;
447 }
448
449 static void dummy_hrtimer_free(struct snd_pcm_substream *substream)
450 {
451         struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
452         dummy_hrtimer_sync(dpcm);
453         kfree(dpcm);
454 }
455
456 static struct dummy_timer_ops dummy_hrtimer_ops = {
457         .create =       dummy_hrtimer_create,
458         .free =         dummy_hrtimer_free,
459         .prepare =      dummy_hrtimer_prepare,
460         .start =        dummy_hrtimer_start,
461         .stop =         dummy_hrtimer_stop,
462         .pointer =      dummy_hrtimer_pointer,
463 };
464
465 #endif /* CONFIG_HIGH_RES_TIMERS */
466
467 /*
468  * PCM interface
469  */
470
471 static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
472 {
473         struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
474
475         switch (cmd) {
476         case SNDRV_PCM_TRIGGER_START:
477         case SNDRV_PCM_TRIGGER_RESUME:
478                 return dummy->timer_ops->start(substream);
479         case SNDRV_PCM_TRIGGER_STOP:
480         case SNDRV_PCM_TRIGGER_SUSPEND:
481                 return dummy->timer_ops->stop(substream);
482         }
483         return -EINVAL;
484 }
485
486 static int dummy_pcm_prepare(struct snd_pcm_substream *substream)
487 {
488         struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
489
490         return dummy->timer_ops->prepare(substream);
491 }
492
493 static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream)
494 {
495         struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
496
497         return dummy->timer_ops->pointer(substream);
498 }
499
500 static struct snd_pcm_hardware dummy_pcm_hardware = {
501         .info =                 (SNDRV_PCM_INFO_MMAP |
502                                  SNDRV_PCM_INFO_INTERLEAVED |
503                                  SNDRV_PCM_INFO_RESUME |
504                                  SNDRV_PCM_INFO_MMAP_VALID),
505         .formats =              USE_FORMATS,
506         .rates =                USE_RATE,
507         .rate_min =             USE_RATE_MIN,
508         .rate_max =             USE_RATE_MAX,
509         .channels_min =         USE_CHANNELS_MIN,
510         .channels_max =         USE_CHANNELS_MAX,
511         .buffer_bytes_max =     MAX_BUFFER_SIZE,
512         .period_bytes_min =     64,
513         .period_bytes_max =     MAX_PERIOD_SIZE,
514         .periods_min =          USE_PERIODS_MIN,
515         .periods_max =          USE_PERIODS_MAX,
516         .fifo_size =            0,
517 };
518
519 static int dummy_pcm_hw_params(struct snd_pcm_substream *substream,
520                                struct snd_pcm_hw_params *hw_params)
521 {
522         if (fake_buffer) {
523                 /* runtime->dma_bytes has to be set manually to allow mmap */
524                 substream->runtime->dma_bytes = params_buffer_bytes(hw_params);
525                 return 0;
526         }
527         return snd_pcm_lib_malloc_pages(substream,
528                                         params_buffer_bytes(hw_params));
529 }
530
531 static int dummy_pcm_hw_free(struct snd_pcm_substream *substream)
532 {
533         if (fake_buffer)
534                 return 0;
535         return snd_pcm_lib_free_pages(substream);
536 }
537
538 static int dummy_pcm_open(struct snd_pcm_substream *substream)
539 {
540         struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
541         struct snd_pcm_runtime *runtime = substream->runtime;
542         int err;
543
544         dummy->timer_ops = &dummy_systimer_ops;
545 #ifdef CONFIG_HIGH_RES_TIMERS
546         if (hrtimer)
547                 dummy->timer_ops = &dummy_hrtimer_ops;
548 #endif
549
550         err = dummy->timer_ops->create(substream);
551         if (err < 0)
552                 return err;
553
554         runtime->hw = dummy_pcm_hardware;
555         if (substream->pcm->device & 1) {
556                 runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
557                 runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
558         }
559         if (substream->pcm->device & 2)
560                 runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |
561                                       SNDRV_PCM_INFO_MMAP_VALID);
562
563         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
564                 err = add_playback_constraints(substream->runtime);
565         else
566                 err = add_capture_constraints(substream->runtime);
567         if (err < 0) {
568                 dummy->timer_ops->free(substream);
569                 return err;
570         }
571         return 0;
572 }
573
574 static int dummy_pcm_close(struct snd_pcm_substream *substream)
575 {
576         struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
577         dummy->timer_ops->free(substream);
578         return 0;
579 }
580
581 /*
582  * dummy buffer handling
583  */
584
585 static void *dummy_page[2];
586
587 static void free_fake_buffer(void)
588 {
589         if (fake_buffer) {
590                 int i;
591                 for (i = 0; i < 2; i++)
592                         if (dummy_page[i]) {
593                                 free_page((unsigned long)dummy_page[i]);
594                                 dummy_page[i] = NULL;
595                         }
596         }
597 }
598
599 static int alloc_fake_buffer(void)
600 {
601         int i;
602
603         if (!fake_buffer)
604                 return 0;
605         for (i = 0; i < 2; i++) {
606                 dummy_page[i] = (void *)get_zeroed_page(GFP_KERNEL);
607                 if (!dummy_page[i]) {
608                         free_fake_buffer();
609                         return -ENOMEM;
610                 }
611         }
612         return 0;
613 }
614
615 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
616                           int channel, snd_pcm_uframes_t pos,
617                           void __user *dst, snd_pcm_uframes_t count)
618 {
619         return 0; /* do nothing */
620 }
621
622 static int dummy_pcm_silence(struct snd_pcm_substream *substream,
623                              int channel, snd_pcm_uframes_t pos,
624                              snd_pcm_uframes_t count)
625 {
626         return 0; /* do nothing */
627 }
628
629 static struct page *dummy_pcm_page(struct snd_pcm_substream *substream,
630                                    unsigned long offset)
631 {
632         return virt_to_page(dummy_page[substream->stream]); /* the same page */
633 }
634
635 static struct snd_pcm_ops dummy_pcm_ops = {
636         .open =         dummy_pcm_open,
637         .close =        dummy_pcm_close,
638         .ioctl =        snd_pcm_lib_ioctl,
639         .hw_params =    dummy_pcm_hw_params,
640         .hw_free =      dummy_pcm_hw_free,
641         .prepare =      dummy_pcm_prepare,
642         .trigger =      dummy_pcm_trigger,
643         .pointer =      dummy_pcm_pointer,
644 };
645
646 static struct snd_pcm_ops dummy_pcm_ops_no_buf = {
647         .open =         dummy_pcm_open,
648         .close =        dummy_pcm_close,
649         .ioctl =        snd_pcm_lib_ioctl,
650         .hw_params =    dummy_pcm_hw_params,
651         .hw_free =      dummy_pcm_hw_free,
652         .prepare =      dummy_pcm_prepare,
653         .trigger =      dummy_pcm_trigger,
654         .pointer =      dummy_pcm_pointer,
655         .copy =         dummy_pcm_copy,
656         .silence =      dummy_pcm_silence,
657         .page =         dummy_pcm_page,
658 };
659
660 static int __devinit snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
661                                         int substreams)
662 {
663         struct snd_pcm *pcm;
664         struct snd_pcm_ops *ops;
665         int err;
666
667         err = snd_pcm_new(dummy->card, "Dummy PCM", device,
668                                substreams, substreams, &pcm);
669         if (err < 0)
670                 return err;
671         dummy->pcm = pcm;
672         if (fake_buffer)
673                 ops = &dummy_pcm_ops_no_buf;
674         else
675                 ops = &dummy_pcm_ops;
676         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, ops);
677         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, ops);
678         pcm->private_data = dummy;
679         pcm->info_flags = 0;
680         strcpy(pcm->name, "Dummy PCM");
681         if (!fake_buffer) {
682                 snd_pcm_lib_preallocate_pages_for_all(pcm,
683                         SNDRV_DMA_TYPE_CONTINUOUS,
684                         snd_dma_continuous_data(GFP_KERNEL),
685                         0, 64*1024);
686         }
687         return 0;
688 }
689
690 /*
691  * mixer interface
692  */
693
694 #define DUMMY_VOLUME(xname, xindex, addr) \
695 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
696   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
697   .name = xname, .index = xindex, \
698   .info = snd_dummy_volume_info, \
699   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
700   .private_value = addr, \
701   .tlv = { .p = db_scale_dummy } }
702
703 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
704                                  struct snd_ctl_elem_info *uinfo)
705 {
706         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
707         uinfo->count = 2;
708         uinfo->value.integer.min = -50;
709         uinfo->value.integer.max = 100;
710         return 0;
711 }
712  
713 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
714                                 struct snd_ctl_elem_value *ucontrol)
715 {
716         struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
717         int addr = kcontrol->private_value;
718
719         spin_lock_irq(&dummy->mixer_lock);
720         ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
721         ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
722         spin_unlock_irq(&dummy->mixer_lock);
723         return 0;
724 }
725
726 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
727                                 struct snd_ctl_elem_value *ucontrol)
728 {
729         struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
730         int change, addr = kcontrol->private_value;
731         int left, right;
732
733         left = ucontrol->value.integer.value[0];
734         if (left < -50)
735                 left = -50;
736         if (left > 100)
737                 left = 100;
738         right = ucontrol->value.integer.value[1];
739         if (right < -50)
740                 right = -50;
741         if (right > 100)
742                 right = 100;
743         spin_lock_irq(&dummy->mixer_lock);
744         change = dummy->mixer_volume[addr][0] != left ||
745                  dummy->mixer_volume[addr][1] != right;
746         dummy->mixer_volume[addr][0] = left;
747         dummy->mixer_volume[addr][1] = right;
748         spin_unlock_irq(&dummy->mixer_lock);
749         return change;
750 }
751
752 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
753
754 #define DUMMY_CAPSRC(xname, xindex, addr) \
755 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
756   .info = snd_dummy_capsrc_info, \
757   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
758   .private_value = addr }
759
760 #define snd_dummy_capsrc_info   snd_ctl_boolean_stereo_info
761  
762 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
763                                 struct snd_ctl_elem_value *ucontrol)
764 {
765         struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
766         int addr = kcontrol->private_value;
767
768         spin_lock_irq(&dummy->mixer_lock);
769         ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
770         ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
771         spin_unlock_irq(&dummy->mixer_lock);
772         return 0;
773 }
774
775 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
776 {
777         struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
778         int change, addr = kcontrol->private_value;
779         int left, right;
780
781         left = ucontrol->value.integer.value[0] & 1;
782         right = ucontrol->value.integer.value[1] & 1;
783         spin_lock_irq(&dummy->mixer_lock);
784         change = dummy->capture_source[addr][0] != left &&
785                  dummy->capture_source[addr][1] != right;
786         dummy->capture_source[addr][0] = left;
787         dummy->capture_source[addr][1] = right;
788         spin_unlock_irq(&dummy->mixer_lock);
789         return change;
790 }
791
792 static struct snd_kcontrol_new snd_dummy_controls[] = {
793 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
794 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
795 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
796 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
797 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
798 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
799 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
800 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
801 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
802 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD)
803 };
804
805 static int __devinit snd_card_dummy_new_mixer(struct snd_dummy *dummy)
806 {
807         struct snd_card *card = dummy->card;
808         unsigned int idx;
809         int err;
810
811         spin_lock_init(&dummy->mixer_lock);
812         strcpy(card->mixername, "Dummy Mixer");
813
814         for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
815                 err = snd_ctl_add(card, snd_ctl_new1(&snd_dummy_controls[idx], dummy));
816                 if (err < 0)
817                         return err;
818         }
819         return 0;
820 }
821
822 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_PROC_FS)
823 /*
824  * proc interface
825  */
826 static void print_formats(struct snd_info_buffer *buffer)
827 {
828         int i;
829
830         for (i = 0; i < SNDRV_PCM_FORMAT_LAST; i++) {
831                 if (dummy_pcm_hardware.formats & (1ULL << i))
832                         snd_iprintf(buffer, " %s", snd_pcm_format_name(i));
833         }
834 }
835
836 static void print_rates(struct snd_info_buffer *buffer)
837 {
838         static int rates[] = {
839                 5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
840                 64000, 88200, 96000, 176400, 192000,
841         };
842         int i;
843
844         if (dummy_pcm_hardware.rates & SNDRV_PCM_RATE_CONTINUOUS)
845                 snd_iprintf(buffer, " continuous");
846         if (dummy_pcm_hardware.rates & SNDRV_PCM_RATE_KNOT)
847                 snd_iprintf(buffer, " knot");
848         for (i = 0; i < ARRAY_SIZE(rates); i++)
849                 if (dummy_pcm_hardware.rates & (1 << i))
850                         snd_iprintf(buffer, " %d", rates[i]);
851 }
852
853 #define get_dummy_int_ptr(ofs) \
854         (unsigned int *)((char *)&dummy_pcm_hardware + (ofs))
855 #define get_dummy_ll_ptr(ofs) \
856         (unsigned long long *)((char *)&dummy_pcm_hardware + (ofs))
857
858 struct dummy_hw_field {
859         const char *name;
860         const char *format;
861         unsigned int offset;
862         unsigned int size;
863 };
864 #define FIELD_ENTRY(item, fmt) {                   \
865         .name = #item,                             \
866         .format = fmt,                             \
867         .offset = offsetof(struct snd_pcm_hardware, item), \
868         .size = sizeof(dummy_pcm_hardware.item) }
869
870 static struct dummy_hw_field fields[] = {
871         FIELD_ENTRY(formats, "%#llx"),
872         FIELD_ENTRY(rates, "%#x"),
873         FIELD_ENTRY(rate_min, "%d"),
874         FIELD_ENTRY(rate_max, "%d"),
875         FIELD_ENTRY(channels_min, "%d"),
876         FIELD_ENTRY(channels_max, "%d"),
877         FIELD_ENTRY(buffer_bytes_max, "%ld"),
878         FIELD_ENTRY(period_bytes_min, "%ld"),
879         FIELD_ENTRY(period_bytes_max, "%ld"),
880         FIELD_ENTRY(periods_min, "%d"),
881         FIELD_ENTRY(periods_max, "%d"),
882 };
883
884 static void dummy_proc_read(struct snd_info_entry *entry,
885                             struct snd_info_buffer *buffer)
886 {
887         int i;
888
889         for (i = 0; i < ARRAY_SIZE(fields); i++) {
890                 snd_iprintf(buffer, "%s ", fields[i].name);
891                 if (fields[i].size == sizeof(int))
892                         snd_iprintf(buffer, fields[i].format,
893                                     *get_dummy_int_ptr(fields[i].offset));
894                 else
895                         snd_iprintf(buffer, fields[i].format,
896                                     *get_dummy_ll_ptr(fields[i].offset));
897                 if (!strcmp(fields[i].name, "formats"))
898                         print_formats(buffer);
899                 else if (!strcmp(fields[i].name, "rates"))
900                         print_rates(buffer);
901                 snd_iprintf(buffer, "\n");
902         }
903 }
904
905 static void dummy_proc_write(struct snd_info_entry *entry,
906                              struct snd_info_buffer *buffer)
907 {
908         char line[64];
909
910         while (!snd_info_get_line(buffer, line, sizeof(line))) {
911                 char item[20];
912                 const char *ptr;
913                 unsigned long long val;
914                 int i;
915
916                 ptr = snd_info_get_str(item, line, sizeof(item));
917                 for (i = 0; i < ARRAY_SIZE(fields); i++) {
918                         if (!strcmp(item, fields[i].name))
919                                 break;
920                 }
921                 if (i >= ARRAY_SIZE(fields))
922                         continue;
923                 snd_info_get_str(item, ptr, sizeof(item));
924                 if (strict_strtoull(item, 0, &val))
925                         continue;
926                 if (fields[i].size == sizeof(int))
927                         *get_dummy_int_ptr(fields[i].offset) = val;
928                 else
929                         *get_dummy_ll_ptr(fields[i].offset) = val;
930         }
931 }
932
933 static void __devinit dummy_proc_init(struct snd_dummy *chip)
934 {
935         struct snd_info_entry *entry;
936
937         if (!snd_card_proc_new(chip->card, "dummy_pcm", &entry)) {
938                 snd_info_set_text_ops(entry, chip, dummy_proc_read);
939                 entry->c.text.write = dummy_proc_write;
940                 entry->mode |= S_IWUSR;
941         }
942 }
943 #else
944 #define dummy_proc_init(x)
945 #endif /* CONFIG_SND_DEBUG && CONFIG_PROC_FS */
946
947 static int __devinit snd_dummy_probe(struct platform_device *devptr)
948 {
949         struct snd_card *card;
950         struct snd_dummy *dummy;
951         int idx, err;
952         int dev = devptr->id;
953
954         err = snd_card_create(index[dev], id[dev], THIS_MODULE,
955                               sizeof(struct snd_dummy), &card);
956         if (err < 0)
957                 return err;
958         dummy = card->private_data;
959         dummy->card = card;
960         for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
961                 if (pcm_substreams[dev] < 1)
962                         pcm_substreams[dev] = 1;
963                 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
964                         pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
965                 err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev]);
966                 if (err < 0)
967                         goto __nodev;
968         }
969         err = snd_card_dummy_new_mixer(dummy);
970         if (err < 0)
971                 goto __nodev;
972         strcpy(card->driver, "Dummy");
973         strcpy(card->shortname, "Dummy");
974         sprintf(card->longname, "Dummy %i", dev + 1);
975
976         dummy_proc_init(dummy);
977
978         snd_card_set_dev(card, &devptr->dev);
979
980         err = snd_card_register(card);
981         if (err == 0) {
982                 platform_set_drvdata(devptr, card);
983                 return 0;
984         }
985       __nodev:
986         snd_card_free(card);
987         return err;
988 }
989
990 static int __devexit snd_dummy_remove(struct platform_device *devptr)
991 {
992         snd_card_free(platform_get_drvdata(devptr));
993         platform_set_drvdata(devptr, NULL);
994         return 0;
995 }
996
997 #ifdef CONFIG_PM
998 static int snd_dummy_suspend(struct platform_device *pdev, pm_message_t state)
999 {
1000         struct snd_card *card = platform_get_drvdata(pdev);
1001         struct snd_dummy *dummy = card->private_data;
1002
1003         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1004         snd_pcm_suspend_all(dummy->pcm);
1005         return 0;
1006 }
1007         
1008 static int snd_dummy_resume(struct platform_device *pdev)
1009 {
1010         struct snd_card *card = platform_get_drvdata(pdev);
1011
1012         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1013         return 0;
1014 }
1015 #endif
1016
1017 #define SND_DUMMY_DRIVER        "snd_dummy"
1018
1019 static struct platform_driver snd_dummy_driver = {
1020         .probe          = snd_dummy_probe,
1021         .remove         = __devexit_p(snd_dummy_remove),
1022 #ifdef CONFIG_PM
1023         .suspend        = snd_dummy_suspend,
1024         .resume         = snd_dummy_resume,
1025 #endif
1026         .driver         = {
1027                 .name   = SND_DUMMY_DRIVER
1028         },
1029 };
1030
1031 static void snd_dummy_unregister_all(void)
1032 {
1033         int i;
1034
1035         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1036                 platform_device_unregister(devices[i]);
1037         platform_driver_unregister(&snd_dummy_driver);
1038         free_fake_buffer();
1039 }
1040
1041 static int __init alsa_card_dummy_init(void)
1042 {
1043         int i, cards, err;
1044
1045         err = platform_driver_register(&snd_dummy_driver);
1046         if (err < 0)
1047                 return err;
1048
1049         err = alloc_fake_buffer();
1050         if (err < 0) {
1051                 platform_driver_unregister(&snd_dummy_driver);
1052                 return err;
1053         }
1054
1055         cards = 0;
1056         for (i = 0; i < SNDRV_CARDS; i++) {
1057                 struct platform_device *device;
1058                 if (! enable[i])
1059                         continue;
1060                 device = platform_device_register_simple(SND_DUMMY_DRIVER,
1061                                                          i, NULL, 0);
1062                 if (IS_ERR(device))
1063                         continue;
1064                 if (!platform_get_drvdata(device)) {
1065                         platform_device_unregister(device);
1066                         continue;
1067                 }
1068                 devices[i] = device;
1069                 cards++;
1070         }
1071         if (!cards) {
1072 #ifdef MODULE
1073                 printk(KERN_ERR "Dummy soundcard not found or device busy\n");
1074 #endif
1075                 snd_dummy_unregister_all();
1076                 return -ENODEV;
1077         }
1078         return 0;
1079 }
1080
1081 static void __exit alsa_card_dummy_exit(void)
1082 {
1083         snd_dummy_unregister_all();
1084 }
1085
1086 module_init(alsa_card_dummy_init)
1087 module_exit(alsa_card_dummy_exit)