Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * ALSA sequencer device management
3 * Copyright (c) 1999 by Takashi Iwai <tiwai@suse.de>
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 *
22 * This device handler separates the card driver module from sequencer
23 * stuff (sequencer core, synth drivers, etc), so that user can avoid
24 * to spend unnecessary resources e.g. if he needs only listening to
25 * MP3s.
26 *
27 * The card (or lowlevel) driver creates a sequencer device entry
28 * via snd_seq_device_new(). This is an entry pointer to communicate
29 * with the sequencer device "driver", which is involved with the
30 * actual part to communicate with the sequencer core.
31 * Each sequencer device entry has an id string and the corresponding
32 * driver with the same id is loaded when required. For example,
33 * lowlevel codes to access emu8000 chip on sbawe card are included in
34 * emu8000-synth module. To activate this module, the hardware
35 * resources like i/o port are passed via snd_seq_device argument.
36 *
37 */
38
39#include <linux/device.h>
40#include <linux/init.h>
41#include <linux/module.h>
42#include <sound/core.h>
43#include <sound/info.h>
44#include <sound/seq_device.h>
45#include <sound/seq_kernel.h>
46#include <sound/initval.h>
47#include <linux/kmod.h>
48#include <linux/slab.h>
49#include <linux/mutex.h>
50
51MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
52MODULE_DESCRIPTION("ALSA sequencer device management");
53MODULE_LICENSE("GPL");
54
55/*
56 * bus definition
57 */
58static int snd_seq_bus_match(struct device *dev, struct device_driver *drv)
59{
60 struct snd_seq_device *sdev = to_seq_dev(dev);
61 struct snd_seq_driver *sdrv = to_seq_drv(drv);
62
63 return strcmp(sdrv->id, sdev->id) == 0 &&
64 sdrv->argsize == sdev->argsize;
65}
66
67static struct bus_type snd_seq_bus_type = {
68 .name = "snd_seq",
69 .match = snd_seq_bus_match,
70};
71
72/*
73 * proc interface -- just for compatibility
74 */
75#ifdef CONFIG_SND_PROC_FS
76static struct snd_info_entry *info_entry;
77
78static int print_dev_info(struct device *dev, void *data)
79{
80 struct snd_seq_device *sdev = to_seq_dev(dev);
81 struct snd_info_buffer *buffer = data;
82
83 snd_iprintf(buffer, "snd-%s,%s,%d\n", sdev->id,
84 dev->driver ? "loaded" : "empty",
85 dev->driver ? 1 : 0);
86 return 0;
87}
88
89static void snd_seq_device_info(struct snd_info_entry *entry,
90 struct snd_info_buffer *buffer)
91{
92 bus_for_each_dev(&snd_seq_bus_type, NULL, buffer, print_dev_info);
93}
94#endif
95
96/*
97 * load all registered drivers (called from seq_clientmgr.c)
98 */
99
100#ifdef CONFIG_MODULES
101/* flag to block auto-loading */
102static atomic_t snd_seq_in_init = ATOMIC_INIT(1); /* blocked as default */
103
104static int request_seq_drv(struct device *dev, void *data)
105{
106 struct snd_seq_device *sdev = to_seq_dev(dev);
107
108 if (!dev->driver)
109 request_module("snd-%s", sdev->id);
110 return 0;
111}
112
113static void autoload_drivers(struct work_struct *work)
114{
115 /* avoid reentrance */
116 if (atomic_inc_return(&snd_seq_in_init) == 1)
117 bus_for_each_dev(&snd_seq_bus_type, NULL, NULL,
118 request_seq_drv);
119 atomic_dec(&snd_seq_in_init);
120}
121
122static DECLARE_WORK(autoload_work, autoload_drivers);
123
124static void queue_autoload_drivers(void)
125{
126 schedule_work(&autoload_work);
127}
128
129void snd_seq_autoload_init(void)
130{
131 atomic_dec(&snd_seq_in_init);
132#ifdef CONFIG_SND_SEQUENCER_MODULE
133 /* initial autoload only when snd-seq is a module */
134 queue_autoload_drivers();
135#endif
136}
137EXPORT_SYMBOL(snd_seq_autoload_init);
138
139void snd_seq_autoload_exit(void)
140{
141 atomic_inc(&snd_seq_in_init);
142}
143EXPORT_SYMBOL(snd_seq_autoload_exit);
144
145void snd_seq_device_load_drivers(void)
146{
147 queue_autoload_drivers();
148 flush_work(&autoload_work);
149}
150EXPORT_SYMBOL(snd_seq_device_load_drivers);
151#define cancel_autoload_drivers() cancel_work_sync(&autoload_work)
152#else
153#define queue_autoload_drivers() /* NOP */
154#define cancel_autoload_drivers() /* NOP */
155#endif
156
157/*
158 * device management
159 */
160static int snd_seq_device_dev_free(struct snd_device *device)
161{
162 struct snd_seq_device *dev = device->device_data;
163
164 cancel_autoload_drivers();
165 put_device(&dev->dev);
166 return 0;
167}
168
169static int snd_seq_device_dev_register(struct snd_device *device)
170{
171 struct snd_seq_device *dev = device->device_data;
172 int err;
173
174 err = device_add(&dev->dev);
175 if (err < 0)
176 return err;
177 if (!dev->dev.driver)
178 queue_autoload_drivers();
179 return 0;
180}
181
182static int snd_seq_device_dev_disconnect(struct snd_device *device)
183{
184 struct snd_seq_device *dev = device->device_data;
185
186 device_del(&dev->dev);
187 return 0;
188}
189
190static void snd_seq_dev_release(struct device *dev)
191{
192 struct snd_seq_device *sdev = to_seq_dev(dev);
193
194 if (sdev->private_free)
195 sdev->private_free(sdev);
196 kfree(sdev);
197}
198
199/*
200 * register a sequencer device
201 * card = card info
202 * device = device number (if any)
203 * id = id of driver
204 * result = return pointer (NULL allowed if unnecessary)
205 */
206int snd_seq_device_new(struct snd_card *card, int device, const char *id,
207 int argsize, struct snd_seq_device **result)
208{
209 struct snd_seq_device *dev;
210 int err;
211 static struct snd_device_ops dops = {
212 .dev_free = snd_seq_device_dev_free,
213 .dev_register = snd_seq_device_dev_register,
214 .dev_disconnect = snd_seq_device_dev_disconnect,
215 };
216
217 if (result)
218 *result = NULL;
219
220 if (snd_BUG_ON(!id))
221 return -EINVAL;
222
223 dev = kzalloc(sizeof(*dev) + argsize, GFP_KERNEL);
224 if (!dev)
225 return -ENOMEM;
226
227 /* set up device info */
228 dev->card = card;
229 dev->device = device;
230 dev->id = id;
231 dev->argsize = argsize;
232
233 device_initialize(&dev->dev);
234 dev->dev.parent = &card->card_dev;
235 dev->dev.bus = &snd_seq_bus_type;
236 dev->dev.release = snd_seq_dev_release;
237 dev_set_name(&dev->dev, "%s-%d-%d", dev->id, card->number, device);
238
239 /* add this device to the list */
240 err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops);
241 if (err < 0) {
242 put_device(&dev->dev);
243 return err;
244 }
245
246 if (result)
247 *result = dev;
248
249 return 0;
250}
251EXPORT_SYMBOL(snd_seq_device_new);
252
253/*
254 * driver registration
255 */
256int __snd_seq_driver_register(struct snd_seq_driver *drv, struct module *mod)
257{
258 if (WARN_ON(!drv->driver.name || !drv->id))
259 return -EINVAL;
260 drv->driver.bus = &snd_seq_bus_type;
261 drv->driver.owner = mod;
262 return driver_register(&drv->driver);
263}
264EXPORT_SYMBOL_GPL(__snd_seq_driver_register);
265
266void snd_seq_driver_unregister(struct snd_seq_driver *drv)
267{
268 driver_unregister(&drv->driver);
269}
270EXPORT_SYMBOL_GPL(snd_seq_driver_unregister);
271
272/*
273 * module part
274 */
275
276static int __init seq_dev_proc_init(void)
277{
278#ifdef CONFIG_SND_PROC_FS
279 info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
280 snd_seq_root);
281 if (info_entry == NULL)
282 return -ENOMEM;
283 info_entry->content = SNDRV_INFO_CONTENT_TEXT;
284 info_entry->c.text.read = snd_seq_device_info;
285 if (snd_info_register(info_entry) < 0) {
286 snd_info_free_entry(info_entry);
287 return -ENOMEM;
288 }
289#endif
290 return 0;
291}
292
293static int __init alsa_seq_device_init(void)
294{
295 int err;
296
297 err = bus_register(&snd_seq_bus_type);
298 if (err < 0)
299 return err;
300 err = seq_dev_proc_init();
301 if (err < 0)
302 bus_unregister(&snd_seq_bus_type);
303 return err;
304}
305
306static void __exit alsa_seq_device_exit(void)
307{
308#ifdef CONFIG_MODULES
309 cancel_work_sync(&autoload_work);
310#endif
311#ifdef CONFIG_SND_PROC_FS
312 snd_info_free_entry(info_entry);
313#endif
314 bus_unregister(&snd_seq_bus_type);
315}
316
317subsys_initcall(alsa_seq_device_init)
318module_exit(alsa_seq_device_exit)