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TOMOYO Linux Cross Reference
Linux/sound/core/vmaster.c

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  1 /*
  2  * Virtual master and slave controls
  3  *
  4  *  Copyright (c) 2008 by Takashi Iwai <tiwai@suse.de>
  5  *
  6  *  This program is free software; you can redistribute it and/or
  7  *  modify it under the terms of the GNU General Public License as
  8  *  published by the Free Software Foundation, version 2.
  9  *
 10  */
 11 
 12 #include <linux/slab.h>
 13 #include <linux/export.h>
 14 #include <sound/core.h>
 15 #include <sound/control.h>
 16 #include <sound/tlv.h>
 17 
 18 /*
 19  * a subset of information returned via ctl info callback
 20  */
 21 struct link_ctl_info {
 22         snd_ctl_elem_type_t type; /* value type */
 23         int count;              /* item count */
 24         int min_val, max_val;   /* min, max values */
 25 };
 26 
 27 /*
 28  * link master - this contains a list of slave controls that are
 29  * identical types, i.e. info returns the same value type and value
 30  * ranges, but may have different number of counts.
 31  *
 32  * The master control is so far only mono volume/switch for simplicity.
 33  * The same value will be applied to all slaves.
 34  */
 35 struct link_master {
 36         struct list_head slaves;
 37         struct link_ctl_info info;
 38         int val;                /* the master value */
 39         unsigned int tlv[4];
 40         void (*hook)(void *private_data, int);
 41         void *hook_private_data;
 42 };
 43 
 44 /*
 45  * link slave - this contains a slave control element
 46  *
 47  * It fakes the control callbacsk with additional attenuation by the
 48  * master control.  A slave may have either one or two channels.
 49  */
 50 
 51 struct link_slave {
 52         struct list_head list;
 53         struct link_master *master;
 54         struct link_ctl_info info;
 55         int vals[2];            /* current values */
 56         unsigned int flags;
 57         struct snd_kcontrol *kctl; /* original kcontrol pointer */
 58         struct snd_kcontrol slave; /* the copy of original control entry */
 59 };
 60 
 61 static int slave_update(struct link_slave *slave)
 62 {
 63         struct snd_ctl_elem_value *uctl;
 64         int err, ch;
 65 
 66         uctl = kmalloc(sizeof(*uctl), GFP_KERNEL);
 67         if (!uctl)
 68                 return -ENOMEM;
 69         uctl->id = slave->slave.id;
 70         err = slave->slave.get(&slave->slave, uctl);
 71         for (ch = 0; ch < slave->info.count; ch++)
 72                 slave->vals[ch] = uctl->value.integer.value[ch];
 73         kfree(uctl);
 74         return 0;
 75 }
 76 
 77 /* get the slave ctl info and save the initial values */
 78 static int slave_init(struct link_slave *slave)
 79 {
 80         struct snd_ctl_elem_info *uinfo;
 81         int err;
 82 
 83         if (slave->info.count) {
 84                 /* already initialized */
 85                 if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
 86                         return slave_update(slave);
 87                 return 0;
 88         }
 89 
 90         uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
 91         if (!uinfo)
 92                 return -ENOMEM;
 93         uinfo->id = slave->slave.id;
 94         err = slave->slave.info(&slave->slave, uinfo);
 95         if (err < 0) {
 96                 kfree(uinfo);
 97                 return err;
 98         }
 99         slave->info.type = uinfo->type;
100         slave->info.count = uinfo->count;
101         if (slave->info.count > 2  ||
102             (slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
103              slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
104                 pr_err("ALSA: vmaster: invalid slave element\n");
105                 kfree(uinfo);
106                 return -EINVAL;
107         }
108         slave->info.min_val = uinfo->value.integer.min;
109         slave->info.max_val = uinfo->value.integer.max;
110         kfree(uinfo);
111 
112         return slave_update(slave);
113 }
114 
115 /* initialize master volume */
116 static int master_init(struct link_master *master)
117 {
118         struct link_slave *slave;
119 
120         if (master->info.count)
121                 return 0; /* already initialized */
122 
123         list_for_each_entry(slave, &master->slaves, list) {
124                 int err = slave_init(slave);
125                 if (err < 0)
126                         return err;
127                 master->info = slave->info;
128                 master->info.count = 1; /* always mono */
129                 /* set full volume as default (= no attenuation) */
130                 master->val = master->info.max_val;
131                 if (master->hook)
132                         master->hook(master->hook_private_data, master->val);
133                 return 1;
134         }
135         return -ENOENT;
136 }
137 
138 static int slave_get_val(struct link_slave *slave,
139                          struct snd_ctl_elem_value *ucontrol)
140 {
141         int err, ch;
142 
143         err = slave_init(slave);
144         if (err < 0)
145                 return err;
146         for (ch = 0; ch < slave->info.count; ch++)
147                 ucontrol->value.integer.value[ch] = slave->vals[ch];
148         return 0;
149 }
150 
151 static int slave_put_val(struct link_slave *slave,
152                          struct snd_ctl_elem_value *ucontrol)
153 {
154         int err, ch, vol;
155 
156         err = master_init(slave->master);
157         if (err < 0)
158                 return err;
159 
160         switch (slave->info.type) {
161         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
162                 for (ch = 0; ch < slave->info.count; ch++)
163                         ucontrol->value.integer.value[ch] &=
164                                 !!slave->master->val;
165                 break;
166         case SNDRV_CTL_ELEM_TYPE_INTEGER:
167                 for (ch = 0; ch < slave->info.count; ch++) {
168                         /* max master volume is supposed to be 0 dB */
169                         vol = ucontrol->value.integer.value[ch];
170                         vol += slave->master->val - slave->master->info.max_val;
171                         if (vol < slave->info.min_val)
172                                 vol = slave->info.min_val;
173                         else if (vol > slave->info.max_val)
174                                 vol = slave->info.max_val;
175                         ucontrol->value.integer.value[ch] = vol;
176                 }
177                 break;
178         }
179         return slave->slave.put(&slave->slave, ucontrol);
180 }
181 
182 /*
183  * ctl callbacks for slaves
184  */
185 static int slave_info(struct snd_kcontrol *kcontrol,
186                       struct snd_ctl_elem_info *uinfo)
187 {
188         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
189         return slave->slave.info(&slave->slave, uinfo);
190 }
191 
192 static int slave_get(struct snd_kcontrol *kcontrol,
193                      struct snd_ctl_elem_value *ucontrol)
194 {
195         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
196         return slave_get_val(slave, ucontrol);
197 }
198 
199 static int slave_put(struct snd_kcontrol *kcontrol,
200                      struct snd_ctl_elem_value *ucontrol)
201 {
202         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
203         int err, ch, changed = 0;
204 
205         err = slave_init(slave);
206         if (err < 0)
207                 return err;
208         for (ch = 0; ch < slave->info.count; ch++) {
209                 if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
210                         changed = 1;
211                         slave->vals[ch] = ucontrol->value.integer.value[ch];
212                 }
213         }
214         if (!changed)
215                 return 0;
216         err = slave_put_val(slave, ucontrol);
217         if (err < 0)
218                 return err;
219         return 1;
220 }
221 
222 static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
223                          int op_flag, unsigned int size,
224                          unsigned int __user *tlv)
225 {
226         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
227         /* FIXME: this assumes that the max volume is 0 dB */
228         return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
229 }
230 
231 static void slave_free(struct snd_kcontrol *kcontrol)
232 {
233         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
234         if (slave->slave.private_free)
235                 slave->slave.private_free(&slave->slave);
236         if (slave->master)
237                 list_del(&slave->list);
238         kfree(slave);
239 }
240 
241 /*
242  * Add a slave control to the group with the given master control
243  *
244  * All slaves must be the same type (returning the same information
245  * via info callback).  The function doesn't check it, so it's your
246  * responsibility.
247  *
248  * Also, some additional limitations:
249  * - at most two channels
250  * - logarithmic volume control (dB level), no linear volume
251  * - master can only attenuate the volume, no gain
252  */
253 int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
254                        unsigned int flags)
255 {
256         struct link_master *master_link = snd_kcontrol_chip(master);
257         struct link_slave *srec;
258 
259         srec = kzalloc(sizeof(*srec) +
260                        slave->count * sizeof(*slave->vd), GFP_KERNEL);
261         if (!srec)
262                 return -ENOMEM;
263         srec->kctl = slave;
264         srec->slave = *slave;
265         memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
266         srec->master = master_link;
267         srec->flags = flags;
268 
269         /* override callbacks */
270         slave->info = slave_info;
271         slave->get = slave_get;
272         slave->put = slave_put;
273         if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
274                 slave->tlv.c = slave_tlv_cmd;
275         slave->private_data = srec;
276         slave->private_free = slave_free;
277 
278         list_add_tail(&srec->list, &master_link->slaves);
279         return 0;
280 }
281 EXPORT_SYMBOL(_snd_ctl_add_slave);
282 
283 /*
284  * ctl callbacks for master controls
285  */
286 static int master_info(struct snd_kcontrol *kcontrol,
287                       struct snd_ctl_elem_info *uinfo)
288 {
289         struct link_master *master = snd_kcontrol_chip(kcontrol);
290         int ret;
291 
292         ret = master_init(master);
293         if (ret < 0)
294                 return ret;
295         uinfo->type = master->info.type;
296         uinfo->count = master->info.count;
297         uinfo->value.integer.min = master->info.min_val;
298         uinfo->value.integer.max = master->info.max_val;
299         return 0;
300 }
301 
302 static int master_get(struct snd_kcontrol *kcontrol,
303                       struct snd_ctl_elem_value *ucontrol)
304 {
305         struct link_master *master = snd_kcontrol_chip(kcontrol);
306         int err = master_init(master);
307         if (err < 0)
308                 return err;
309         ucontrol->value.integer.value[0] = master->val;
310         return 0;
311 }
312 
313 static int sync_slaves(struct link_master *master, int old_val, int new_val)
314 {
315         struct link_slave *slave;
316         struct snd_ctl_elem_value *uval;
317 
318         uval = kmalloc(sizeof(*uval), GFP_KERNEL);
319         if (!uval)
320                 return -ENOMEM;
321         list_for_each_entry(slave, &master->slaves, list) {
322                 master->val = old_val;
323                 uval->id = slave->slave.id;
324                 slave_get_val(slave, uval);
325                 master->val = new_val;
326                 slave_put_val(slave, uval);
327         }
328         kfree(uval);
329         return 0;
330 }
331 
332 static int master_put(struct snd_kcontrol *kcontrol,
333                       struct snd_ctl_elem_value *ucontrol)
334 {
335         struct link_master *master = snd_kcontrol_chip(kcontrol);
336         int err, new_val, old_val;
337         bool first_init;
338 
339         err = master_init(master);
340         if (err < 0)
341                 return err;
342         first_init = err;
343         old_val = master->val;
344         new_val = ucontrol->value.integer.value[0];
345         if (new_val == old_val)
346                 return 0;
347 
348         err = sync_slaves(master, old_val, new_val);
349         if (err < 0)
350                 return err;
351         if (master->hook && !first_init)
352                 master->hook(master->hook_private_data, master->val);
353         return 1;
354 }
355 
356 static void master_free(struct snd_kcontrol *kcontrol)
357 {
358         struct link_master *master = snd_kcontrol_chip(kcontrol);
359         struct link_slave *slave, *n;
360 
361         /* free all slave links and retore the original slave kctls */
362         list_for_each_entry_safe(slave, n, &master->slaves, list) {
363                 struct snd_kcontrol *sctl = slave->kctl;
364                 struct list_head olist = sctl->list;
365                 memcpy(sctl, &slave->slave, sizeof(*sctl));
366                 memcpy(sctl->vd, slave->slave.vd,
367                        sctl->count * sizeof(*sctl->vd));
368                 sctl->list = olist; /* keep the current linked-list */
369                 kfree(slave);
370         }
371         kfree(master);
372 }
373 
374 
375 /**
376  * snd_ctl_make_virtual_master - Create a virtual master control
377  * @name: name string of the control element to create
378  * @tlv: optional TLV int array for dB information
379  *
380  * Creates a virtual master control with the given name string.
381  *
382  * After creating a vmaster element, you can add the slave controls
383  * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
384  *
385  * The optional argument @tlv can be used to specify the TLV information
386  * for dB scale of the master control.  It should be a single element
387  * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
388  * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
389  *
390  * Return: The created control element, or %NULL for errors (ENOMEM).
391  */
392 struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
393                                                  const unsigned int *tlv)
394 {
395         struct link_master *master;
396         struct snd_kcontrol *kctl;
397         struct snd_kcontrol_new knew;
398 
399         memset(&knew, 0, sizeof(knew));
400         knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
401         knew.name = name;
402         knew.info = master_info;
403 
404         master = kzalloc(sizeof(*master), GFP_KERNEL);
405         if (!master)
406                 return NULL;
407         INIT_LIST_HEAD(&master->slaves);
408 
409         kctl = snd_ctl_new1(&knew, master);
410         if (!kctl) {
411                 kfree(master);
412                 return NULL;
413         }
414         /* override some callbacks */
415         kctl->info = master_info;
416         kctl->get = master_get;
417         kctl->put = master_put;
418         kctl->private_free = master_free;
419 
420         /* additional (constant) TLV read */
421         if (tlv &&
422             (tlv[0] == SNDRV_CTL_TLVT_DB_SCALE ||
423              tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX ||
424              tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX_MUTE)) {
425                 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
426                 memcpy(master->tlv, tlv, sizeof(master->tlv));
427                 kctl->tlv.p = master->tlv;
428         }
429 
430         return kctl;
431 }
432 EXPORT_SYMBOL(snd_ctl_make_virtual_master);
433 
434 /**
435  * snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
436  * @kcontrol: vmaster kctl element
437  * @hook: the hook function
438  * @private_data: the private_data pointer to be saved
439  *
440  * Adds the given hook to the vmaster control element so that it's called
441  * at each time when the value is changed.
442  *
443  * Return: Zero.
444  */
445 int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
446                              void (*hook)(void *private_data, int),
447                              void *private_data)
448 {
449         struct link_master *master = snd_kcontrol_chip(kcontrol);
450         master->hook = hook;
451         master->hook_private_data = private_data;
452         return 0;
453 }
454 EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
455 
456 /**
457  * snd_ctl_sync_vmaster - Sync the vmaster slaves and hook
458  * @kcontrol: vmaster kctl element
459  * @hook_only: sync only the hook
460  *
461  * Forcibly call the put callback of each slave and call the hook function
462  * to synchronize with the current value of the given vmaster element.
463  * NOP when NULL is passed to @kcontrol.
464  */
465 void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
466 {
467         struct link_master *master;
468         bool first_init = false;
469 
470         if (!kcontrol)
471                 return;
472         master = snd_kcontrol_chip(kcontrol);
473         if (!hook_only) {
474                 int err = master_init(master);
475                 if (err < 0)
476                         return;
477                 first_init = err;
478                 err = sync_slaves(master, master->val, master->val);
479                 if (err < 0)
480                         return;
481         }
482 
483         if (master->hook && !first_init)
484                 master->hook(master->hook_private_data, master->val);
485 }
486 EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);
487 

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