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310 lines
7.1 KiB
310 lines
7.1 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* ALSA sequencer device management |
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* Copyright (c) 1999 by Takashi Iwai <[email protected]> |
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* |
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*---------------------------------------------------------------- |
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* |
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* This device handler separates the card driver module from sequencer |
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* stuff (sequencer core, synth drivers, etc), so that user can avoid |
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* to spend unnecessary resources e.g. if he needs only listening to |
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* MP3s. |
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* |
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* The card (or lowlevel) driver creates a sequencer device entry |
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* via snd_seq_device_new(). This is an entry pointer to communicate |
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* with the sequencer device "driver", which is involved with the |
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* actual part to communicate with the sequencer core. |
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* Each sequencer device entry has an id string and the corresponding |
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* driver with the same id is loaded when required. For example, |
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* lowlevel codes to access emu8000 chip on sbawe card are included in |
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* emu8000-synth module. To activate this module, the hardware |
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* resources like i/o port are passed via snd_seq_device argument. |
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*/ |
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#include <linux/device.h> |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <sound/core.h> |
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#include <sound/info.h> |
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#include <sound/seq_device.h> |
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#include <sound/seq_kernel.h> |
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#include <sound/initval.h> |
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#include <linux/kmod.h> |
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#include <linux/slab.h> |
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#include <linux/mutex.h> |
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MODULE_AUTHOR("Takashi Iwai <[email protected]>"); |
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MODULE_DESCRIPTION("ALSA sequencer device management"); |
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MODULE_LICENSE("GPL"); |
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/* |
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* bus definition |
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*/ |
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static int snd_seq_bus_match(struct device *dev, struct device_driver *drv) |
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{ |
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struct snd_seq_device *sdev = to_seq_dev(dev); |
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struct snd_seq_driver *sdrv = to_seq_drv(drv); |
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return strcmp(sdrv->id, sdev->id) == 0 && |
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sdrv->argsize == sdev->argsize; |
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} |
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static struct bus_type snd_seq_bus_type = { |
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.name = "snd_seq", |
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.match = snd_seq_bus_match, |
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}; |
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/* |
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* proc interface -- just for compatibility |
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*/ |
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#ifdef CONFIG_SND_PROC_FS |
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static struct snd_info_entry *info_entry; |
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static int print_dev_info(struct device *dev, void *data) |
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{ |
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struct snd_seq_device *sdev = to_seq_dev(dev); |
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struct snd_info_buffer *buffer = data; |
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snd_iprintf(buffer, "snd-%s,%s,%d\n", sdev->id, |
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dev->driver ? "loaded" : "empty", |
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dev->driver ? 1 : 0); |
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return 0; |
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} |
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static void snd_seq_device_info(struct snd_info_entry *entry, |
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struct snd_info_buffer *buffer) |
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{ |
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bus_for_each_dev(&snd_seq_bus_type, NULL, buffer, print_dev_info); |
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} |
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#endif |
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/* |
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* load all registered drivers (called from seq_clientmgr.c) |
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*/ |
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#ifdef CONFIG_MODULES |
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/* flag to block auto-loading */ |
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static atomic_t snd_seq_in_init = ATOMIC_INIT(1); /* blocked as default */ |
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static int request_seq_drv(struct device *dev, void *data) |
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{ |
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struct snd_seq_device *sdev = to_seq_dev(dev); |
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if (!dev->driver) |
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request_module("snd-%s", sdev->id); |
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return 0; |
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} |
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static void autoload_drivers(struct work_struct *work) |
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{ |
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/* avoid reentrance */ |
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if (atomic_inc_return(&snd_seq_in_init) == 1) |
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bus_for_each_dev(&snd_seq_bus_type, NULL, NULL, |
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request_seq_drv); |
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atomic_dec(&snd_seq_in_init); |
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} |
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static DECLARE_WORK(autoload_work, autoload_drivers); |
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static void queue_autoload_drivers(void) |
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{ |
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schedule_work(&autoload_work); |
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} |
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void snd_seq_autoload_init(void) |
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{ |
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atomic_dec(&snd_seq_in_init); |
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#ifdef CONFIG_SND_SEQUENCER_MODULE |
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/* initial autoload only when snd-seq is a module */ |
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queue_autoload_drivers(); |
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#endif |
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} |
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EXPORT_SYMBOL(snd_seq_autoload_init); |
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void snd_seq_autoload_exit(void) |
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{ |
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atomic_inc(&snd_seq_in_init); |
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} |
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EXPORT_SYMBOL(snd_seq_autoload_exit); |
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void snd_seq_device_load_drivers(void) |
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{ |
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queue_autoload_drivers(); |
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flush_work(&autoload_work); |
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} |
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EXPORT_SYMBOL(snd_seq_device_load_drivers); |
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static inline void cancel_autoload_drivers(void) |
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{ |
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cancel_work_sync(&autoload_work); |
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} |
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#else |
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static inline void queue_autoload_drivers(void) |
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{ |
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} |
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static inline void cancel_autoload_drivers(void) |
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{ |
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} |
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#endif |
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/* |
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* device management |
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*/ |
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static int snd_seq_device_dev_free(struct snd_device *device) |
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{ |
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struct snd_seq_device *dev = device->device_data; |
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cancel_autoload_drivers(); |
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if (dev->private_free) |
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dev->private_free(dev); |
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put_device(&dev->dev); |
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return 0; |
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} |
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static int snd_seq_device_dev_register(struct snd_device *device) |
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{ |
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struct snd_seq_device *dev = device->device_data; |
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int err; |
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err = device_add(&dev->dev); |
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if (err < 0) |
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return err; |
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if (!dev->dev.driver) |
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queue_autoload_drivers(); |
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return 0; |
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} |
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static int snd_seq_device_dev_disconnect(struct snd_device *device) |
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{ |
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struct snd_seq_device *dev = device->device_data; |
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device_del(&dev->dev); |
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return 0; |
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} |
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static void snd_seq_dev_release(struct device *dev) |
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{ |
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kfree(to_seq_dev(dev)); |
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} |
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/* |
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* register a sequencer device |
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* card = card info |
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* device = device number (if any) |
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* id = id of driver |
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* result = return pointer (NULL allowed if unnecessary) |
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*/ |
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int snd_seq_device_new(struct snd_card *card, int device, const char *id, |
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int argsize, struct snd_seq_device **result) |
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{ |
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struct snd_seq_device *dev; |
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int err; |
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static const struct snd_device_ops dops = { |
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.dev_free = snd_seq_device_dev_free, |
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.dev_register = snd_seq_device_dev_register, |
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.dev_disconnect = snd_seq_device_dev_disconnect, |
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}; |
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if (result) |
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*result = NULL; |
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if (snd_BUG_ON(!id)) |
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return -EINVAL; |
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dev = kzalloc(sizeof(*dev) + argsize, GFP_KERNEL); |
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if (!dev) |
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return -ENOMEM; |
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/* set up device info */ |
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dev->card = card; |
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dev->device = device; |
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dev->id = id; |
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dev->argsize = argsize; |
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device_initialize(&dev->dev); |
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dev->dev.parent = &card->card_dev; |
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dev->dev.bus = &snd_seq_bus_type; |
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dev->dev.release = snd_seq_dev_release; |
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dev_set_name(&dev->dev, "%s-%d-%d", dev->id, card->number, device); |
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/* add this device to the list */ |
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err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops); |
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if (err < 0) { |
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put_device(&dev->dev); |
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return err; |
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} |
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if (result) |
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*result = dev; |
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return 0; |
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} |
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EXPORT_SYMBOL(snd_seq_device_new); |
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/* |
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* driver registration |
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*/ |
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int __snd_seq_driver_register(struct snd_seq_driver *drv, struct module *mod) |
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{ |
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if (WARN_ON(!drv->driver.name || !drv->id)) |
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return -EINVAL; |
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drv->driver.bus = &snd_seq_bus_type; |
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drv->driver.owner = mod; |
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return driver_register(&drv->driver); |
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} |
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EXPORT_SYMBOL_GPL(__snd_seq_driver_register); |
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void snd_seq_driver_unregister(struct snd_seq_driver *drv) |
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{ |
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driver_unregister(&drv->driver); |
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} |
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EXPORT_SYMBOL_GPL(snd_seq_driver_unregister); |
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/* |
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* module part |
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*/ |
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static int __init seq_dev_proc_init(void) |
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{ |
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#ifdef CONFIG_SND_PROC_FS |
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info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers", |
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snd_seq_root); |
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if (info_entry == NULL) |
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return -ENOMEM; |
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info_entry->content = SNDRV_INFO_CONTENT_TEXT; |
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info_entry->c.text.read = snd_seq_device_info; |
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if (snd_info_register(info_entry) < 0) { |
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snd_info_free_entry(info_entry); |
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return -ENOMEM; |
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} |
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#endif |
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return 0; |
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} |
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static int __init alsa_seq_device_init(void) |
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{ |
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int err; |
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err = bus_register(&snd_seq_bus_type); |
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if (err < 0) |
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return err; |
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err = seq_dev_proc_init(); |
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if (err < 0) |
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bus_unregister(&snd_seq_bus_type); |
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return err; |
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} |
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static void __exit alsa_seq_device_exit(void) |
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{ |
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#ifdef CONFIG_MODULES |
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cancel_work_sync(&autoload_work); |
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#endif |
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#ifdef CONFIG_SND_PROC_FS |
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snd_info_free_entry(info_entry); |
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#endif |
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bus_unregister(&snd_seq_bus_type); |
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} |
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subsys_initcall(alsa_seq_device_init) |
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module_exit(alsa_seq_device_exit)
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