--- /dev/null
+/*
+ * 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_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_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_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)
Code Review / kvmfornfv.git / blobdiff