[ALSA] Optimize for config without PROC_FS

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / sound / core / init.c

/*
 *  Initialization routines
 *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
 *
 *
 *   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;
};

unsigned int snd_cards_lock = 0;        /* locked for registering/using */
struct snd_card *snd_cards[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = NULL};
DEFINE_RWLOCK(snd_card_rwlock);

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

#ifdef CONFIG_PROC_FS
static void snd_card_id_read(struct snd_info_entry *entry,
                             struct snd_info_buffer *buffer)
{
        snd_iprintf(buffer, "%s\n", entry->card->id);
}

static inline int init_info_for_card(struct snd_card *card)
{
        int err;
        struct snd_info_entry *entry;

        if ((err = snd_info_card_register(card)) < 0) {
                snd_printd("unable to create card info\n");
                return err;
        }
        if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
                snd_printd("unable to create card entry\n");
                return err;
        }
        entry->c.text.read_size = PAGE_SIZE;
        entry->c.text.read = snd_card_id_read;
        if (snd_info_register(entry) < 0) {
                snd_info_free_entry(entry);
                entry = NULL;
        }
        card->proc_id = entry;
        return 0;
}
#else /* !CONFIG_PROC_FS */
#define init_info_for_card(card)
#endif

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 structure. Creates the ALSA control interface
 *  (which is blocked until snd_card_register function is called).
 */
struct snd_card *snd_card_new(int idx, const char *xid,
                         struct module *module, int extra_size)
{
        struct snd_card *card;
        int err;

        if (extra_size < 0)
                extra_size = 0;
        card = kzalloc(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 < SNDRV_CARDS; idx2++)
                        if (~snd_cards_lock & idx & 1<<idx2) {
                                idx = idx2;
                                if (idx >= snd_ecards_limit)
                                        snd_ecards_limit = idx + 1;
                                break;
                        }
        } 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_create(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(struct snd_card);
        return card;

      __error_ctl:
        snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
      __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(struct snd_card *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() */

#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(struct snd_card *card)
{
        struct snd_shutdown_f_ops *s_f_ops;

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

#ifdef CONFIG_PM
        wake_up(&card->power_sleep);
#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_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);
        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)
{
        struct snd_card *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(struct snd_card *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(struct snd_card *card)
{
        int i, len, idx_flag = 0, loops = SNDRV_CARDS;
        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)\n", 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) {
                        if (id[len-1] != '9')
                                id[len-1]++;
                        else
                                id[len-1] = 'A';
                } 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)
                                spos++;
                        *spos++ = '_';
                        *spos++ = '1';
                        *spos++ = '\0';
                        idx_flag++;
                }
        }
}

/**
 *  snd_card_register - register the soundcard
 *  @card: soundcard structure
 *
 *  This function registers all the devices assigned to the soundcard.
 *  Until calling this, the ALSA control interface is blocked from the
 *  external accesses.  Thus, you should call this function at the end
 *  of the initialization of the card.
 *
 *  Returns zero otherwise a negative error code if the registrain failed.
 */
int snd_card_register(struct snd_card *card)
{
        int err;

        snd_assert(card != NULL, return -EINVAL);
        if ((err = snd_device_register_all(card)) < 0)
                return err;
        write_lock(&snd_card_rwlock);
        if (snd_cards[card->number]) {
                /* already registered */
                write_unlock(&snd_card_rwlock);
                return 0;
        }
        if (card->id[0] == '\0')
                choose_default_id(card);
        snd_cards[card->number] = card;
        write_unlock(&snd_card_rwlock);
        init_info_for_card(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_REGISTER);
#endif
        return 0;
}

#ifdef CONFIG_PROC_FS
static struct snd_info_entry *snd_card_info_entry = NULL;

static void snd_card_info_read(struct snd_info_entry *entry,
                               struct snd_info_buffer *buffer)
{
        int idx, count;
        struct snd_card *card;

        for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
                read_lock(&snd_card_rwlock);
                if ((card = snd_cards[idx]) != NULL) {
                        count++;
                        snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
                                        idx,
                                        card->id,
                                        card->driver,
                                        card->shortname);
                        snd_iprintf(buffer, "                      %s\n",
                                        card->longname);
                }
                read_unlock(&snd_card_rwlock);
        }
        if (!count)
                snd_iprintf(buffer, "--- no soundcards ---\n");
}

#ifdef CONFIG_SND_OSSEMUL

void snd_card_info_read_oss(struct snd_info_buffer *buffer)
{
        int idx, count;
        struct snd_card *card;

        for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
                read_lock(&snd_card_rwlock);
                if ((card = snd_cards[idx]) != NULL) {
                        count++;
                        snd_iprintf(buffer, "%s\n", card->longname);
                }
                read_unlock(&snd_card_rwlock);
        }
        if (!count) {
                snd_iprintf(buffer, "--- no soundcards ---\n");
        }
}

#endif

#ifdef MODULE
static struct snd_info_entry *snd_card_module_info_entry;
static void snd_card_module_info_read(struct snd_info_entry *entry,
                                      struct snd_info_buffer *buffer)
{
        int idx;
        struct snd_card *card;

        for (idx = 0; idx < SNDRV_CARDS; idx++) {
                read_lock(&snd_card_rwlock);
                if ((card = snd_cards[idx]) != NULL)
                        snd_iprintf(buffer, "%2i %s\n",
                                    idx, card->module->name);
                read_unlock(&snd_card_rwlock);
        }
}
#endif

int __init snd_card_info_init(void)
{
        struct snd_info_entry *entry;

        entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
        if (! entry)
                return -ENOMEM;
        entry->c.text.read_size = PAGE_SIZE;
        entry->c.text.read = snd_card_info_read;
        if (snd_info_register(entry) < 0) {
                snd_info_free_entry(entry);
                return -ENOMEM;
        }
        snd_card_info_entry = entry;

#ifdef MODULE
        entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
        if (entry) {
                entry->c.text.read_size = PAGE_SIZE;
                entry->c.text.read = snd_card_module_info_read;
                if (snd_info_register(entry) < 0)
                        snd_info_free_entry(entry);
                else
                        snd_card_module_info_entry = entry;
        }
#endif

        return 0;
}

int __exit snd_card_info_done(void)
{
        snd_info_unregister(snd_card_info_entry);
#ifdef MODULE
        snd_info_unregister(snd_card_module_info_entry);
#endif
        return 0;
}

#endif /* CONFIG_PROC_FS */

/**
 *  snd_component_add - add a component string
 *  @card: soundcard structure
 *  @component: the component id string
 *
 *  This function adds the component id string to the supported list.
 *  The component can be referred from the alsa-lib.
 *
 *  Returns zero otherwise a negative error code.
 */
  
int snd_component_add(struct snd_card *card, const char *component)
{
        char *ptr;
        int len = strlen(component);

        ptr = strstr(card->components, component);
        if (ptr != NULL) {
                if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
                        return 1;
        }
        if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
                snd_BUG();
                return -ENOMEM;
        }
        if (card->components[0] != '\0')
                strcat(card->components, " ");
        strcat(card->components, component);
        return 0;
}

/**
 *  snd_card_file_add - add the file to the file list of the card
 *  @card: soundcard structure
 *  @file: file pointer
 *
 *  This function adds the file to the file linked-list of the card.
 *  This linked-list is used to keep tracking the connection state,
 *  and to avoid the release of busy resources by hotplug.
 *
 *  Returns zero or a negative error code.
 */
int snd_card_file_add(struct snd_card *card, struct file *file)
{
        struct snd_monitor_file *mfile;

        mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
        if (mfile == NULL)
                return -ENOMEM;
        mfile->file = file;
        mfile->next = NULL;
        spin_lock(&card->files_lock);
        if (card->shutdown) {
                spin_unlock(&card->files_lock);
                kfree(mfile);
                return -ENODEV;
        }
        mfile->next = card->files;
        card->files = mfile;
        spin_unlock(&card->files_lock);
        return 0;
}

/**
 *  snd_card_file_remove - remove the file from the file list
 *  @card: soundcard structure
 *  @file: file pointer
 *
 *  This function removes the file formerly added to the card via
 *  snd_card_file_add() function.
 *  If all files are removed and the release of the card is
 *  scheduled, it will wake up the the thread to call snd_card_free()
 *  (see snd_card_free_in_thread() function).
 *
 *  Returns zero or a negative error code.
 */
int snd_card_file_remove(struct snd_card *card, struct file *file)
{
        struct snd_monitor_file *mfile, *pfile = NULL;

        spin_lock(&card->files_lock);
        mfile = card->files;
        while (mfile) {
                if (mfile->file == file) {
                        if (pfile)
                                pfile->next = mfile->next;
                        else
                                card->files = mfile->next;
                        break;
                }
                pfile = mfile;
                mfile = mfile->next;
        }
        spin_unlock(&card->files_lock);
        if (card->files == NULL)
                wake_up(&card->shutdown_sleep);
        if (!mfile) {
                snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
                return -ENOENT;
        }
        kfree(mfile);
        return 0;
}

#ifdef CONFIG_PM
/**
 *  snd_power_wait - wait until the power-state is changed.
 *  @card: soundcard structure
 *  @power_state: expected power state
 *  @file: file structure for the O_NONBLOCK check (optional)
 *
 *  Waits until the power-state is changed.
 *
 *  Note: the power lock must be active before call.
 */
int snd_power_wait(struct snd_card *card, unsigned int power_state, struct file *file)
{
        wait_queue_t wait;
        int result = 0;

        /* fastpath */
        if (snd_power_get_state(card) == power_state)
                return 0;
        init_waitqueue_entry(&wait, current);
        add_wait_queue(&card->power_sleep, &wait);
        while (1) {
                if (card->shutdown) {
                        result = -ENODEV;
                        break;
                }
                if (snd_power_get_state(card) == power_state)
                        break;
#if 0 /* block all devices */
                if (file && (file->f_flags & O_NONBLOCK)) {
                        result = -EAGAIN;
                        break;
                }
#endif
                set_current_state(TASK_UNINTERRUPTIBLE);
                snd_power_unlock(card);
                schedule_timeout(30 * HZ);
                snd_power_lock(card);
        }
        remove_wait_queue(&card->power_sleep, &wait);
        return result;
}

#endif /* CONFIG_PM */