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#else
152#define queue_autoload_drivers() /* NOP */
153#endif
154
155/*
156 * device management
157 */
158static int snd_seq_device_dev_free(struct snd_device *device)
159{
160	struct snd_seq_device *dev = device->device_data;
161
162	put_device(&dev->dev);
163	return 0;
164}
165
166static int snd_seq_device_dev_register(struct snd_device *device)
167{
168	struct snd_seq_device *dev = device->device_data;
169	int err;
170
171	err = device_add(&dev->dev);
172	if (err < 0)
173		return err;
174	if (!dev->dev.driver)
175		queue_autoload_drivers();
176	return 0;
177}
178
179static int snd_seq_device_dev_disconnect(struct snd_device *device)
180{
181	struct snd_seq_device *dev = device->device_data;
182
183	device_del(&dev->dev);
184	return 0;
185}
186
187static void snd_seq_dev_release(struct device *dev)
188{
189	struct snd_seq_device *sdev = to_seq_dev(dev);
190
191	if (sdev->private_free)
192		sdev->private_free(sdev);
193	kfree(sdev);
194}
195
196/*
197 * register a sequencer device
198 * card = card info
199 * device = device number (if any)
200 * id = id of driver
201 * result = return pointer (NULL allowed if unnecessary)
202 */
203int snd_seq_device_new(struct snd_card *card, int device, const char *id,
204		       int argsize, struct snd_seq_device **result)
205{
206	struct snd_seq_device *dev;
207	int err;
208	static struct snd_device_ops dops = {
209		.dev_free = snd_seq_device_dev_free,
210		.dev_register = snd_seq_device_dev_register,
211		.dev_disconnect = snd_seq_device_dev_disconnect,
212	};
213
214	if (result)
215		*result = NULL;
216
217	if (snd_BUG_ON(!id))
218		return -EINVAL;
219
220	dev = kzalloc(sizeof(*dev) + argsize, GFP_KERNEL);
221	if (!dev)
222		return -ENOMEM;
223
224	/* set up device info */
225	dev->card = card;
226	dev->device = device;
227	dev->id = id;
228	dev->argsize = argsize;
229
230	device_initialize(&dev->dev);
231	dev->dev.parent = &card->card_dev;
232	dev->dev.bus = &snd_seq_bus_type;
233	dev->dev.release = snd_seq_dev_release;
234	dev_set_name(&dev->dev, "%s-%d-%d", dev->id, card->number, device);
235
236	/* add this device to the list */
237	err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops);
238	if (err < 0) {
239		put_device(&dev->dev);
240		return err;
241	}
242
243	if (result)
244		*result = dev;
245
246	return 0;
247}
248EXPORT_SYMBOL(snd_seq_device_new);
249
250/*
251 * driver registration
252 */
253int __snd_seq_driver_register(struct snd_seq_driver *drv, struct module *mod)
254{
255	if (WARN_ON(!drv->driver.name || !drv->id))
256		return -EINVAL;
257	drv->driver.bus = &snd_seq_bus_type;
258	drv->driver.owner = mod;
259	return driver_register(&drv->driver);
260}
261EXPORT_SYMBOL_GPL(__snd_seq_driver_register);
262
263void snd_seq_driver_unregister(struct snd_seq_driver *drv)
264{
265	driver_unregister(&drv->driver);
266}
267EXPORT_SYMBOL_GPL(snd_seq_driver_unregister);
268
269/*
270 * module part
271 */
272
273static int __init seq_dev_proc_init(void)
274{
275#ifdef CONFIG_SND_PROC_FS
276	info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
277						  snd_seq_root);
278	if (info_entry == NULL)
279		return -ENOMEM;
280	info_entry->content = SNDRV_INFO_CONTENT_TEXT;
281	info_entry->c.text.read = snd_seq_device_info;
282	if (snd_info_register(info_entry) < 0) {
283		snd_info_free_entry(info_entry);
284		return -ENOMEM;
285	}
286#endif
287	return 0;
288}
289
290static int __init alsa_seq_device_init(void)
291{
292	int err;
293
294	err = bus_register(&snd_seq_bus_type);
295	if (err < 0)
296		return err;
297	err = seq_dev_proc_init();
298	if (err < 0)
299		bus_unregister(&snd_seq_bus_type);
300	return err;
301}
302
303static void __exit alsa_seq_device_exit(void)
304{
305#ifdef CONFIG_MODULES
306	cancel_work_sync(&autoload_work);
307#endif
308#ifdef CONFIG_SND_PROC_FS
309	snd_info_free_entry(info_entry);
310#endif
311	bus_unregister(&snd_seq_bus_type);
312}
313
314subsys_initcall(alsa_seq_device_init)
315module_exit(alsa_seq_device_exit)
316