summaryrefslogtreecommitdiffstats
path: root/kernel/sound/core/seq/seq_device.c
blob: c4acf17e9f5e50183bd3cb1226ec289f19be3843 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
/*
 *  ALSA sequencer device management
 *  Copyright (c) 1999 by Takashi Iwai <tiwai@suse.de>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 *
 *----------------------------------------------------------------
 *
 * This device handler separates the card driver module from sequencer
 * stuff (sequencer core, synth drivers, etc), so that user can avoid
 * to spend unnecessary resources e.g. if he needs only listening to
 * MP3s.
 *
 * The card (or lowlevel) driver creates a sequencer device entry
 * via snd_seq_device_new().  This is an entry pointer to communicate
 * with the sequencer device "driver", which is involved with the
 * actual part to communicate with the sequencer core.
 * Each sequencer device entry has an id string and the corresponding
 * driver with the same id is loaded when required.  For example,
 * lowlevel codes to access emu8000 chip on sbawe card are included in
 * emu8000-synth module.  To activate this module, the hardware
 * resources like i/o port are passed via snd_seq_device argument.
 *
 */

#include <linux/device.h>
#include <linux/init.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/info.h>
#include <sound/seq_device.h>
#include <sound/seq_kernel.h>
#include <sound/initval.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/mutex.h>

MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
MODULE_DESCRIPTION("ALSA sequencer device management");
MODULE_LICENSE("GPL");

/*
 * bus definition
 */
static int snd_seq_bus_match(struct device *dev, struct device_driver *drv)
{
	struct snd_seq_device *sdev = to_seq_dev(dev);
	struct snd_seq_driver *sdrv = to_seq_drv(drv);

	return strcmp(sdrv->id, sdev->id) == 0 &&
		sdrv->argsize == sdev->argsize;
}

static struct bus_type snd_seq_bus_type = {
	.name = "snd_seq",
	.match = snd_seq_bus_match,
};

/*
 * proc interface -- just for compatibility
 */
#ifdef CONFIG_SND_PROC_FS
static struct snd_info_entry *info_entry;

static int print_dev_info(struct device *dev, void *data)
{
	struct snd_seq_device *sdev = to_seq_dev(dev);
	struct snd_info_buffer *buffer = data;

	snd_iprintf(buffer, "snd-%s,%s,%d\n", sdev->id,
		    dev->driver ? "loaded" : "empty",
		    dev->driver ? 1 : 0);
	return 0;
}

static void snd_seq_device_info(struct snd_info_entry *entry,
				struct snd_info_buffer *buffer)
{
	bus_for_each_dev(&snd_seq_bus_type, NULL, buffer, print_dev_info);
}
#endif

/*
 * load all registered drivers (called from seq_clientmgr.c)
 */

#ifdef CONFIG_MODULES
/* flag to block auto-loading */
static atomic_t snd_seq_in_init = ATOMIC_INIT(1); /* blocked as default */

static int request_seq_drv(struct device *dev, void *data)
{
	struct snd_seq_device *sdev = to_seq_dev(dev);

	if (!dev->driver)
		request_module("snd-%s", sdev->id);
	return 0;
}

static void autoload_drivers(struct work_struct *work)
{
	/* avoid reentrance */
	if (atomic_inc_return(&snd_seq_in_init) == 1)
		bus_for_each_dev(&snd_seq_bus_type, NULL, NULL,
				 request_seq_drv);
	atomic_dec(&snd_seq_in_init);
}

static DECLARE_WORK(autoload_work, autoload_drivers);

static void queue_autoload_drivers(void)
{
	schedule_work(&autoload_work);
}

void snd_seq_autoload_init(void)
{
	atomic_dec(&snd_seq_in_init);
#ifdef CONFIG_SND_SEQUENCER_MODULE
	/* initial autoload only when snd-seq is a module */
	queue_autoload_drivers();
#endif
}
EXPORT_SYMBOL(snd_seq_autoload_init);

void snd_seq_autoload_exit(void)
{
	atomic_inc(&snd_seq_in_init);
}
EXPORT_SYMBOL(snd_seq_autoload_exit);

void snd_seq_device_load_drivers(void)
{
	queue_autoload_drivers();
	flush_work(&autoload_work);
}
EXPORT_SYMBOL(snd_seq_device_load_drivers);
#else
#define queue_autoload_drivers() /* NOP */
#endif

/*
 * device management
 */
static int snd_seq_device_dev_free(struct snd_device *device)
{
	struct snd_seq_device *dev = device->device_data;

	put_device(&dev->dev);
	return 0;
}

static int snd_seq_device_dev_register(struct snd_device *device)
{
	struct snd_seq_device *dev = device->device_data;
	int err;

	err = device_add(&dev->dev);
	if (err < 0)
		return err;
	if (!dev->dev.driver)
		queue_autoload_drivers();
	return 0;
}

static int snd_seq_device_dev_disconnect(struct snd_device *device)
{
	struct snd_seq_device *dev = device->device_data;

	device_del(&dev->dev);
	return 0;
}

static void snd_seq_dev_release(struct device *dev)
{
	struct snd_seq_device *sdev = to_seq_dev(dev);

	if (sdev->private_free)
		sdev->private_free(sdev);
	kfree(sdev);
}

/*
 * register a sequencer device
 * card = card info
 * device = device number (if any)
 * id = id of driver
 * result = return pointer (NULL allowed if unnecessary)
 */
int snd_seq_device_new(struct snd_card *card, int device, const char *id,
		       int argsize, struct snd_seq_device **result)
{
	struct snd_seq_device *dev;
	int err;
	static struct snd_device_ops dops = {
		.dev_free = snd_seq_device_dev_free,
		.dev_register = snd_seq_device_dev_register,
		.dev_disconnect = snd_seq_device_dev_disconnect,
	};

	if (result)
		*result = NULL;

	if (snd_BUG_ON(!id))
		return -EINVAL;

	dev = kzalloc(sizeof(*dev) + argsize, GFP_KERNEL);
	if (!dev)
		return -ENOMEM;

	/* set up device info */
	dev->card = card;
	dev->device = device;
	dev->id = id;
	dev->argsize = argsize;

	device_initialize(&dev->dev);
	dev->dev.parent = &card->card_dev;
	dev->dev.bus = &snd_seq_bus_type;
	dev->dev.release = snd_seq_dev_release;
	dev_set_name(&dev->dev, "%s-%d-%d", dev->id, card->number, device);

	/* add this device to the list */
	err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops);
	if (err < 0) {
		put_device(&dev->dev);
		return err;
	}
	
	if (result)
		*result = dev;

	return 0;
}
EXPORT_SYMBOL(snd_seq_device_new);

/*
 * driver registration
 */
int __snd_seq_driver_register(struct snd_seq_driver *drv, struct module *mod)
{
	if (WARN_ON(!drv->driver.name || !drv->id))
		return -EINVAL;
	drv->driver.bus = &snd_seq_bus_type;
	drv->driver.owner = mod;
	return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(__snd_seq_driver_register);

void snd_seq_driver_unregister(struct snd_seq_driver *drv)
{
	driver_unregister(&drv->driver);
}
EXPORT_SYMBOL_GPL(snd_seq_driver_unregister);

/*
 * module part
 */

static int __init seq_dev_proc_init(void)
{
#ifdef CONFIG_SND_PROC_FS
	info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
						  snd_seq_root);
	if (info_entry == NULL)
		return -ENOMEM;
	info_entry->content = SNDRV_INFO_CONTENT_TEXT;
	info_entry->c.text.read = snd_seq_device_info;
	if (snd_info_register(info_entry) < 0) {
		snd_info_free_entry(info_entry);
		return -ENOMEM;
	}
#endif
	return 0;
}

static int __init alsa_seq_device_init(void)
{
	int err;

	err = bus_register(&snd_seq_bus_type);
	if (err < 0)
		return err;
	err = seq_dev_proc_init();
	if (err < 0)
		bus_unregister(&snd_seq_bus_type);
	return err;
}

static void __exit alsa_seq_device_exit(void)
{
#ifdef CONFIG_MODULES
	cancel_work_sync(&autoload_work);
#endif
#ifdef CONFIG_SND_PROC_FS
	snd_info_free_entry(info_entry);
#endif
	bus_unregister(&snd_seq_bus_type);
}

subsys_initcall(alsa_seq_device_init)
module_exit(alsa_seq_device_exit)