init.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 811 行 · 第 1/2 页

/*
 *  Initialization routines
 *  Copyright (c) by Jaroslav Kysela <[e-mail]>
 *
 *
 *   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
 *
 */

#include <sound/driver.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/ctype.h>
#include <linux/pci.h>
#include <linux/pm.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/info.h>

struct snd_shutdown_f_ops {
	struct file_operations f_ops;
	struct snd_shutdown_f_ops *next;
};

int snd_cards_count = 0;
unsigned int snd_cards_lock = 0;	/* locked for registering/using */
snd_card_t *snd_cards[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = NULL};
rwlock_t snd_card_rwlock = RW_LOCK_UNLOCKED;

#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
int (*snd_mixer_oss_notify_callback)(snd_card_t *card, int free_flag);
#endif

static void snd_card_id_read(snd_info_entry_t *entry, snd_info_buffer_t * buffer)
{
	snd_iprintf(buffer, "%s\n", entry->card->id);
}

static void snd_card_free_thread(void * __card);

/**
 *  snd_card_new - create and initialize a soundcard structure
 *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
 *  @xid: card identification (ASCII string)
 *  @module: top level module for locking
 *  @extra_size: allocate this extra size after the main soundcard structure
 *
 *  Creates and initializes a soundcard structure.
 *
 *  Returns kmallocated snd_card_t structure. Creates the ALSA control interface
 *  (which is blocked until snd_card_register function is called).
 */
snd_card_t *snd_card_new(int idx, const char *xid,
			 struct module *module, int extra_size)
{
	snd_card_t *card;
	int err;

	if (extra_size < 0)
		extra_size = 0;
	card = kcalloc(1, sizeof(*card) + extra_size, GFP_KERNEL);
	if (card == NULL)
		return NULL;
	if (xid) {
		if (!snd_info_check_reserved_words(xid))
			goto __error;
		strlcpy(card->id, xid, sizeof(card->id));
	}
	err = 0;
	write_lock(&snd_card_rwlock);
	if (idx < 0) {
		int idx2;
		for (idx2 = 0; idx2 < snd_ecards_limit; idx2++)
			if (!(snd_cards_lock & (1 << idx2))) {
				idx = idx2;
				break;
			}
		if (idx < 0 && snd_ecards_limit < SNDRV_CARDS)
			/* for dynamically additional devices like hotplug:
			 * increment the limit if still free slot exists.
			 */
			idx = snd_ecards_limit++;
	} else if (idx < snd_ecards_limit) {
		if (snd_cards_lock & (1 << idx))
			err = -ENODEV;	/* invalid */
	} else if (idx < SNDRV_CARDS)
		snd_ecards_limit = idx + 1; /* increase the limit */
	else
		err = -ENODEV;
	if (idx < 0 || err < 0) {
		write_unlock(&snd_card_rwlock);
		snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i)\n", idx, snd_ecards_limit - 1);
		goto __error;
	}
	snd_cards_lock |= 1 << idx;		/* lock it */
	write_unlock(&snd_card_rwlock);
	card->number = idx;
	card->module = module;
	INIT_LIST_HEAD(&card->devices);
	init_rwsem(&card->controls_rwsem);
	rwlock_init(&card->ctl_files_rwlock);
	INIT_LIST_HEAD(&card->controls);
	INIT_LIST_HEAD(&card->ctl_files);
	spin_lock_init(&card->files_lock);
	init_waitqueue_head(&card->shutdown_sleep);
	INIT_WORK(&card->free_workq, snd_card_free_thread, card);
#ifdef CONFIG_PM
	init_MUTEX(&card->power_lock);
	init_waitqueue_head(&card->power_sleep);
#endif
	/* the control interface cannot be accessed from the user space until */
	/* snd_cards_bitmask and snd_cards are set with snd_card_register */
	if ((err = snd_ctl_register(card)) < 0) {
		snd_printd("unable to register control minors\n");
		goto __error;
	}
	if ((err = snd_info_card_create(card)) < 0) {
		snd_printd("unable to create card info\n");
		goto __error_ctl;
	}
	if (extra_size > 0)
		card->private_data = (char *)card + sizeof(snd_card_t);
	return card;

      __error_ctl:
	snd_ctl_unregister(card);
      __error:
	kfree(card);
      	return NULL;
}

static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
{
	return POLLERR | POLLNVAL;
}

/**
 *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
 *  @card: soundcard structure
 *
 *  Disconnects all APIs from the file-operations (user space).
 *
 *  Returns zero, otherwise a negative error code.
 *
 *  Note: The current implementation replaces all active file->f_op with special
 *        dummy file operations (they do nothing except release).
 */
int snd_card_disconnect(snd_card_t * card)
{
	struct snd_monitor_file *mfile;
	struct file *file;
	struct snd_shutdown_f_ops *s_f_ops;
	struct file_operations *f_ops, *old_f_ops;
	int err;

	spin_lock(&card->files_lock);
	if (card->shutdown) {
		spin_unlock(&card->files_lock);
		return 0;
	}
	card->shutdown = 1;
	spin_unlock(&card->files_lock);

	/* phase 1: disable fops (user space) operations for ALSA API */
	write_lock(&snd_card_rwlock);
	snd_cards[card->number] = NULL;
	write_unlock(&snd_card_rwlock);
	
	/* phase 2: replace file->f_op with special dummy operations */
	
	spin_lock(&card->files_lock);
	mfile = card->files;
	while (mfile) {
		file = mfile->file;

		/* it's critical part, use endless loop */
		/* we have no room to fail */
		s_f_ops = kmalloc(sizeof(struct snd_shutdown_f_ops), GFP_ATOMIC);
		if (s_f_ops == NULL)
			panic("Atomic allocation failed for snd_shutdown_f_ops!");

		f_ops = &s_f_ops->f_ops;

		memset(f_ops, 0, sizeof(*f_ops));
		f_ops->owner = file->f_op->owner;
		f_ops->release = file->f_op->release;
		f_ops->poll = snd_disconnect_poll;

		s_f_ops->next = card->s_f_ops;
		card->s_f_ops = s_f_ops;
		
		f_ops = fops_get(f_ops);

		old_f_ops = file->f_op;
		file->f_op = f_ops;	/* must be atomic */
		fops_put(old_f_ops);
		
		mfile = mfile->next;
	}
	spin_unlock(&card->files_lock);	

	/* phase 3: notify all connected devices about disconnection */
	/* at this point, they cannot respond to any calls except release() */

	snd_ctl_disconnect(card);

#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
	if (snd_mixer_oss_notify_callback)
		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
#endif

	/* notify all devices that we are disconnected */
	err = snd_device_disconnect_all(card);
	if (err < 0)
		snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);

	return 0;	
}

/**
 *  snd_card_free - frees given soundcard structure
 *  @card: soundcard structure
 *
 *  This function releases the soundcard structure and the all assigned
 *  devices automatically.  That is, you don't have to release the devices
 *  by yourself.
 *
 *  Returns zero. Frees all associated devices and frees the control
 *  interface associated to given soundcard.
 */
int snd_card_free(snd_card_t * card)
{
	struct snd_shutdown_f_ops *s_f_ops;

	if (card == NULL)
		return -EINVAL;
	write_lock(&snd_card_rwlock);
	snd_cards[card->number] = NULL;
	snd_cards_count--;
	write_unlock(&snd_card_rwlock);

#ifdef CONFIG_PM
	wake_up(&card->power_sleep);
#ifdef CONFIG_ISA
	if (card->pm_dev) {
		pm_unregister(card->pm_dev);
		card->pm_dev = NULL;
	}
#endif
#endif

	/* wait, until all devices are ready for the free operation */
	wait_event(card->shutdown_sleep, card->files == NULL);

#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
	if (snd_mixer_oss_notify_callback)
		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
#endif
	if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
		snd_printk(KERN_ERR "unable to free all devices (pre)\n");
		/* Fatal, but this situation should never occur */
	}
	if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
		snd_printk(KERN_ERR "unable to free all devices (normal)\n");
		/* Fatal, but this situation should never occur */
	}
	if (snd_ctl_unregister(card) < 0) {
		snd_printk(KERN_ERR "unable to unregister control minors\n");
		/* Not fatal error */
	}
	if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
		snd_printk(KERN_ERR "unable to free all devices (post)\n");
		/* Fatal, but this situation should never occur */
	}
	if (card->private_free)
		card->private_free(card);
	if (card->proc_id)
		snd_info_unregister(card->proc_id);
	if (snd_info_card_free(card) < 0) {
		snd_printk(KERN_WARNING "unable to free card info\n");
		/* Not fatal error */
	}
	while (card->s_f_ops) {
		s_f_ops = card->s_f_ops;
		card->s_f_ops = s_f_ops->next;
		kfree(s_f_ops);
	}
	write_lock(&snd_card_rwlock);
	snd_cards_lock &= ~(1 << card->number);
	write_unlock(&snd_card_rwlock);
	kfree(card);
	return 0;
}

static void snd_card_free_thread(void * __card)
{
	snd_card_t *card = __card;
	struct module * module = card->module;

	if (!try_module_get(module)) {
		snd_printk(KERN_ERR "unable to lock toplevel module for card %i in free thread\n", card->number);
		module = NULL;
	}

	snd_card_free(card);

	module_put(module);
}

/**
 *  snd_card_free_in_thread - call snd_card_free() in thread
 *  @card: soundcard structure
 *
 *  This function schedules the call of snd_card_free() function in a
 *  work queue.  When all devices are released (non-busy), the work
 *  is woken up and calls snd_card_free().
 *
 *  When a card can be disconnected at any time by hotplug service,
 *  this function should be used in disconnect (or detach) callback
 *  instead of calling snd_card_free() directly.
 *  
 *  Returns - zero otherwise a negative error code if the start of thread failed.
 */
int snd_card_free_in_thread(snd_card_t * card)
{
	if (card->files == NULL) {
		snd_card_free(card);
		return 0;
	}

	if (schedule_work(&card->free_workq))
		return 0;

	snd_printk(KERN_ERR "schedule_work() failed in snd_card_free_in_thread for card %i\n", card->number);
	/* try to free the structure immediately */
	snd_card_free(card);
	return -EFAULT;
}

static void choose_default_id(snd_card_t * card)
{
	int i, len, idx_flag = 0, loops = 8;
	char *id, *spos;
	
	id = spos = card->shortname;	
	while (*id != '\0') {
		if (*id == ' ')
			spos = id + 1;
		id++;
	}
	id = card->id;
	while (*spos != '\0' && !isalnum(*spos))
		spos++;
	if (isdigit(*spos))
		*id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
	while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
		if (isalnum(*spos))
			*id++ = *spos;
		spos++;
	}
	*id = '\0';

	id = card->id;
	
	if (*id == '\0')
		strcpy(id, "default");

	while (1) {
	      	if (loops-- == 0) {
      			snd_printk(KERN_ERR "unable to choose default card id (%s)", id);
      			strcpy(card->id, card->proc_root->name);
      			return;
      		}
	      	if (!snd_info_check_reserved_words(id))
      			goto __change;
		for (i = 0; i < snd_ecards_limit; i++) {
			if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
				goto __change;
		}
		break;

	      __change:
		len = strlen(id);
		if (idx_flag)
			id[len-1]++;
		else if ((size_t)len <= sizeof(card->id) - 3) {
			strcat(id, "_1");
			idx_flag++;
		} else {
			spos = id + len - 2;
			if ((size_t)len <= sizeof(card->id) - 2)