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32 results

am335x-nano.dts

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  • seq_clientmgr.c 65.57 KiB
    /*
     *  ALSA sequencer Client Manager
     *  Copyright (c) 1998-2001 by Frank van de Pol <fvdpol@coil.demon.nl>
     *                             Jaroslav Kysela <perex@perex.cz>
     *                             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
     *
     */
    
    #include <linux/init.h>
    #include <linux/export.h>
    #include <linux/slab.h>
    #include <sound/core.h>
    #include <sound/minors.h>
    #include <linux/kmod.h>
    
    #include <sound/seq_kernel.h>
    #include "seq_clientmgr.h"
    #include "seq_memory.h"
    #include "seq_queue.h"
    #include "seq_timer.h"
    #include "seq_info.h"
    #include "seq_system.h"
    #include <sound/seq_device.h>
    #ifdef CONFIG_COMPAT
    #include <linux/compat.h>
    #endif
    
    /* Client Manager
    
     * this module handles the connections of userland and kernel clients
     * 
     */
    
    /*
     * There are four ranges of client numbers (last two shared):
     * 0..15: global clients
     * 16..127: statically allocated client numbers for cards 0..27
     * 128..191: dynamically allocated client numbers for cards 28..31
     * 128..191: dynamically allocated client numbers for applications
     */
    
    /* number of kernel non-card clients */
    #define SNDRV_SEQ_GLOBAL_CLIENTS	16
    /* clients per cards, for static clients */
    #define SNDRV_SEQ_CLIENTS_PER_CARD	4
    /* dynamically allocated client numbers (both kernel drivers and user space) */
    #define SNDRV_SEQ_DYNAMIC_CLIENTS_BEGIN	128
    
    #define SNDRV_SEQ_LFLG_INPUT	0x0001
    #define SNDRV_SEQ_LFLG_OUTPUT	0x0002
    #define SNDRV_SEQ_LFLG_OPEN	(SNDRV_SEQ_LFLG_INPUT|SNDRV_SEQ_LFLG_OUTPUT)
    
    static DEFINE_SPINLOCK(clients_lock);
    static DEFINE_MUTEX(register_mutex);
    
    /*
     * client table
     */
    static char clienttablock[SNDRV_SEQ_MAX_CLIENTS];
    static struct snd_seq_client *clienttab[SNDRV_SEQ_MAX_CLIENTS];
    static struct snd_seq_usage client_usage;
    
    /*
     * prototypes
     */
    static int bounce_error_event(struct snd_seq_client *client,
    			      struct snd_seq_event *event,
    			      int err, int atomic, int hop);
    static int snd_seq_deliver_single_event(struct snd_seq_client *client,
    					struct snd_seq_event *event,
    					int filter, int atomic, int hop);
    
    /*
     */
    static inline unsigned short snd_seq_file_flags(struct file *file)
    {
            switch (file->f_mode & (FMODE_READ | FMODE_WRITE)) {
            case FMODE_WRITE:
                    return SNDRV_SEQ_LFLG_OUTPUT;
            case FMODE_READ:
                    return SNDRV_SEQ_LFLG_INPUT;
            default:
                    return SNDRV_SEQ_LFLG_OPEN;
            }
    }
    
    static inline int snd_seq_write_pool_allocated(struct snd_seq_client *client)
    {
    	return snd_seq_total_cells(client->pool) > 0;
    }
    
    /* return pointer to client structure for specified id */
    static struct snd_seq_client *clientptr(int clientid)
    {
    	if (clientid < 0 || clientid >= SNDRV_SEQ_MAX_CLIENTS) {
    		pr_debug("ALSA: seq: oops. Trying to get pointer to client %d\n",
    			   clientid);
    		return NULL;
    	}
    	return clienttab[clientid];
    }
    
    struct snd_seq_client *snd_seq_client_use_ptr(int clientid)
    {
    	unsigned long flags;
    	struct snd_seq_client *client;
    
    	if (clientid < 0 || clientid >= SNDRV_SEQ_MAX_CLIENTS) {
    		pr_debug("ALSA: seq: oops. Trying to get pointer to client %d\n",
    			   clientid);
    		return NULL;
    	}
    	spin_lock_irqsave(&clients_lock, flags);
    	client = clientptr(clientid);
    	if (client)
    		goto __lock;
    	if (clienttablock[clientid]) {
    		spin_unlock_irqrestore(&clients_lock, flags);
    		return NULL;
    	}
    	spin_unlock_irqrestore(&clients_lock, flags);
    #ifdef CONFIG_MODULES
    	if (!in_interrupt()) {
    		static char client_requested[SNDRV_SEQ_GLOBAL_CLIENTS];
    		static char card_requested[SNDRV_CARDS];
    		if (clientid < SNDRV_SEQ_GLOBAL_CLIENTS) {
    			int idx;
    			
    			if (!client_requested[clientid]) {
    				client_requested[clientid] = 1;
    				for (idx = 0; idx < 15; idx++) {
    					if (seq_client_load[idx] < 0)
    						break;
    					if (seq_client_load[idx] == clientid) {
    						request_module("snd-seq-client-%i",
    							       clientid);
    						break;
    					}
    				}
    			}
    		} else if (clientid < SNDRV_SEQ_DYNAMIC_CLIENTS_BEGIN) {
    			int card = (clientid - SNDRV_SEQ_GLOBAL_CLIENTS) /
    				SNDRV_SEQ_CLIENTS_PER_CARD;
    			if (card < snd_ecards_limit) {
    				if (! card_requested[card]) {
    					card_requested[card] = 1;
    					snd_request_card(card);
    				}
    				snd_seq_device_load_drivers();
    			}
    		}
    		spin_lock_irqsave(&clients_lock, flags);
    		client = clientptr(clientid);
    		if (client)
    			goto __lock;
    		spin_unlock_irqrestore(&clients_lock, flags);
    	}
    #endif
    	return NULL;
    
          __lock:
    	snd_use_lock_use(&client->use_lock);
    	spin_unlock_irqrestore(&clients_lock, flags);
    	return client;
    }
    
    static void usage_alloc(struct snd_seq_usage *res, int num)
    {
    	res->cur += num;
    	if (res->cur > res->peak)
    		res->peak = res->cur;
    }
    
    static void usage_free(struct snd_seq_usage *res, int num)
    {
    	res->cur -= num;
    }
    
    /* initialise data structures */
    int __init client_init_data(void)
    {
    	/* zap out the client table */
    	memset(&clienttablock, 0, sizeof(clienttablock));
    	memset(&clienttab, 0, sizeof(clienttab));
    	return 0;
    }
    
    
    static struct snd_seq_client *seq_create_client1(int client_index, int poolsize)
    {
    	unsigned long flags;
    	int c;
    	struct snd_seq_client *client;
    
    	/* init client data */
    	client = kzalloc(sizeof(*client), GFP_KERNEL);
    	if (client == NULL)
    		return NULL;
    	client->pool = snd_seq_pool_new(poolsize);
    	if (client->pool == NULL) {
    		kfree(client);
    		return NULL;
    	}
    	client->type = NO_CLIENT;
    	snd_use_lock_init(&client->use_lock);
    	rwlock_init(&client->ports_lock);
    	mutex_init(&client->ports_mutex);
    	INIT_LIST_HEAD(&client->ports_list_head);
    	mutex_init(&client->ioctl_mutex);
    
    	/* find free slot in the client table */
    	spin_lock_irqsave(&clients_lock, flags);
    	if (client_index < 0) {
    		for (c = SNDRV_SEQ_DYNAMIC_CLIENTS_BEGIN;
    		     c < SNDRV_SEQ_MAX_CLIENTS;
    		     c++) {
    			if (clienttab[c] || clienttablock[c])
    				continue;
    			clienttab[client->number = c] = client;
    			spin_unlock_irqrestore(&clients_lock, flags);
    			return client;
    		}
    	} else {
    		if (clienttab[client_index] == NULL && !clienttablock[client_index]) {
    			clienttab[client->number = client_index] = client;
    			spin_unlock_irqrestore(&clients_lock, flags);
    			return client;
    		}
    	}
    	spin_unlock_irqrestore(&clients_lock, flags);
    	snd_seq_pool_delete(&client->pool);
    	kfree(client);
    	return NULL;	/* no free slot found or busy, return failure code */
    }
    
    
    static int seq_free_client1(struct snd_seq_client *client)
    {
    	unsigned long flags;
    
    	if (!client)
    		return 0;
    	snd_seq_delete_all_ports(client);
    	snd_seq_queue_client_leave(client->number);
    	spin_lock_irqsave(&clients_lock, flags);
    	clienttablock[client->number] = 1;
    	clienttab[client->number] = NULL;
    	spin_unlock_irqrestore(&clients_lock, flags);
    	snd_use_lock_sync(&client->use_lock);
    	snd_seq_queue_client_termination(client->number);
    	if (client->pool)
    		snd_seq_pool_delete(&client->pool);
    	spin_lock_irqsave(&clients_lock, flags);
    	clienttablock[client->number] = 0;
    	spin_unlock_irqrestore(&clients_lock, flags);
    	return 0;
    }
    
    
    static void seq_free_client(struct snd_seq_client * client)
    {
    	mutex_lock(&register_mutex);
    	switch (client->type) {
    	case NO_CLIENT:
    		pr_warn("ALSA: seq: Trying to free unused client %d\n",
    			client->number);
    		break;
    	case USER_CLIENT:
    	case KERNEL_CLIENT:
    		seq_free_client1(client);
    		usage_free(&client_usage, 1);
    		break;
    
    	default:
    		pr_err("ALSA: seq: Trying to free client %d with undefined type = %d\n",
    			   client->number, client->type);
    	}
    	mutex_unlock(&register_mutex);
    
    	snd_seq_system_client_ev_client_exit(client->number);
    }
    
    
    
    /* -------------------------------------------------------- */
    
    /* create a user client */
    static int snd_seq_open(struct inode *inode, struct file *file)
    {
    	int c, mode;			/* client id */
    	struct snd_seq_client *client;
    	struct snd_seq_user_client *user;
    	int err;
    
    	err = nonseekable_open(inode, file);
    	if (err < 0)
    		return err;
    
    	if (mutex_lock_interruptible(&register_mutex))
    		return -ERESTARTSYS;
    	client = seq_create_client1(-1, SNDRV_SEQ_DEFAULT_EVENTS);
    	if (client == NULL) {
    		mutex_unlock(&register_mutex);
    		return -ENOMEM;	/* failure code */
    	}
    
    	mode = snd_seq_file_flags(file);
    	if (mode & SNDRV_SEQ_LFLG_INPUT)
    		client->accept_input = 1;
    	if (mode & SNDRV_SEQ_LFLG_OUTPUT)
    		client->accept_output = 1;
    
    	user = &client->data.user;
    	user->fifo = NULL;
    	user->fifo_pool_size = 0;
    
    	if (mode & SNDRV_SEQ_LFLG_INPUT) {
    		user->fifo_pool_size = SNDRV_SEQ_DEFAULT_CLIENT_EVENTS;
    		user->fifo = snd_seq_fifo_new(user->fifo_pool_size);
    		if (user->fifo == NULL) {
    			seq_free_client1(client);
    			kfree(client);
    			mutex_unlock(&register_mutex);
    			return -ENOMEM;
    		}
    	}
    
    	usage_alloc(&client_usage, 1);
    	client->type = USER_CLIENT;
    	mutex_unlock(&register_mutex);
    
    	c = client->number;
    	file->private_data = client;
    
    	/* fill client data */
    	user->file = file;
    	sprintf(client->name, "Client-%d", c);
    	client->data.user.owner = get_pid(task_pid(current));
    
    	/* make others aware this new client */
    	snd_seq_system_client_ev_client_start(c);
    
    	return 0;
    }
    
    /* delete a user client */
    static int snd_seq_release(struct inode *inode, struct file *file)
    {
    	struct snd_seq_client *client = file->private_data;
    
    	if (client) {
    		seq_free_client(client);
    		if (client->data.user.fifo)
    			snd_seq_fifo_delete(&client->data.user.fifo);
    		put_pid(client->data.user.owner);
    		kfree(client);
    	}
    
    	return 0;
    }
    
    
    /* handle client read() */
    /* possible error values:
     *	-ENXIO	invalid client or file open mode
     *	-ENOSPC	FIFO overflow (the flag is cleared after this error report)
     *	-EINVAL	no enough user-space buffer to write the whole event
     *	-EFAULT	seg. fault during copy to user space
     */
    static ssize_t snd_seq_read(struct file *file, char __user *buf, size_t count,
    			    loff_t *offset)
    {
    	struct snd_seq_client *client = file->private_data;
    	struct snd_seq_fifo *fifo;
    	int err;
    	long result = 0;
    	struct snd_seq_event_cell *cell;
    
    	if (!(snd_seq_file_flags(file) & SNDRV_SEQ_LFLG_INPUT))
    		return -ENXIO;
    
    	if (!access_ok(VERIFY_WRITE, buf, count))
    		return -EFAULT;
    
    	/* check client structures are in place */
    	if (snd_BUG_ON(!client))
    		return -ENXIO;
    
    	if (!client->accept_input || (fifo = client->data.user.fifo) == NULL)
    		return -ENXIO;
    
    	if (atomic_read(&fifo->overflow) > 0) {
    		/* buffer overflow is detected */
    		snd_seq_fifo_clear(fifo);
    		/* return error code */
    		return -ENOSPC;
    	}
    
    	cell = NULL;
    	err = 0;
    	snd_seq_fifo_lock(fifo);
    
    	/* while data available in queue */
    	while (count >= sizeof(struct snd_seq_event)) {
    		int nonblock;
    
    		nonblock = (file->f_flags & O_NONBLOCK) || result > 0;
    		if ((err = snd_seq_fifo_cell_out(fifo, &cell, nonblock)) < 0) {
    			break;
    		}
    		if (snd_seq_ev_is_variable(&cell->event)) {
    			struct snd_seq_event tmpev;
    			tmpev = cell->event;
    			tmpev.data.ext.len &= ~SNDRV_SEQ_EXT_MASK;
    			if (copy_to_user(buf, &tmpev, sizeof(struct snd_seq_event))) {
    				err = -EFAULT;
    				break;
    			}
    			count -= sizeof(struct snd_seq_event);
    			buf += sizeof(struct snd_seq_event);
    			err = snd_seq_expand_var_event(&cell->event, count,
    						       (char __force *)buf, 0,
    						       sizeof(struct snd_seq_event));
    			if (err < 0)
    				break;
    			result += err;
    			count -= err;
    			buf += err;
    		} else {
    			if (copy_to_user(buf, &cell->event, sizeof(struct snd_seq_event))) {
    				err = -EFAULT;
    				break;
    			}
    			count -= sizeof(struct snd_seq_event);
    			buf += sizeof(struct snd_seq_event);
    		}
    		snd_seq_cell_free(cell);
    		cell = NULL; /* to be sure */
    		result += sizeof(struct snd_seq_event);
    	}
    
    	if (err < 0) {
    		if (cell)
    			snd_seq_fifo_cell_putback(fifo, cell);
    		if (err == -EAGAIN && result > 0)
    			err = 0;
    	}
    	snd_seq_fifo_unlock(fifo);
    
    	return (err < 0) ? err : result;
    }
    
    
    /*
     * check access permission to the port
     */
    static int check_port_perm(struct snd_seq_client_port *port, unsigned int flags)
    {
    	if ((port->capability & flags) != flags)
    		return 0;
    	return flags;
    }
    
    /*
     * check if the destination client is available, and return the pointer
     * if filter is non-zero, client filter bitmap is tested.
     */
    static struct snd_seq_client *get_event_dest_client(struct snd_seq_event *event,
    						    int filter)
    {
    	struct snd_seq_client *dest;
    
    	dest = snd_seq_client_use_ptr(event->dest.client);
    	if (dest == NULL)
    		return NULL;
    	if (! dest->accept_input)
    		goto __not_avail;
    	if ((dest->filter & SNDRV_SEQ_FILTER_USE_EVENT) &&
    	    ! test_bit(event->type, dest->event_filter))
    		goto __not_avail;
    	if (filter && !(dest->filter & filter))
    		goto __not_avail;
    
    	return dest; /* ok - accessible */
    __not_avail:
    	snd_seq_client_unlock(dest);
    	return NULL;
    }
    
    
    /*
     * Return the error event.
     *
     * If the receiver client is a user client, the original event is
     * encapsulated in SNDRV_SEQ_EVENT_BOUNCE as variable length event.  If
     * the original event is also variable length, the external data is
     * copied after the event record. 
     * If the receiver client is a kernel client, the original event is
     * quoted in SNDRV_SEQ_EVENT_KERNEL_ERROR, since this requires no extra
     * kmalloc.
     */
    static int bounce_error_event(struct snd_seq_client *client,
    			      struct snd_seq_event *event,
    			      int err, int atomic, int hop)
    {
    	struct snd_seq_event bounce_ev;
    	int result;
    
    	if (client == NULL ||
    	    ! (client->filter & SNDRV_SEQ_FILTER_BOUNCE) ||
    	    ! client->accept_input)
    		return 0; /* ignored */
    
    	/* set up quoted error */
    	memset(&bounce_ev, 0, sizeof(bounce_ev));
    	bounce_ev.type = SNDRV_SEQ_EVENT_KERNEL_ERROR;
    	bounce_ev.flags = SNDRV_SEQ_EVENT_LENGTH_FIXED;
    	bounce_ev.queue = SNDRV_SEQ_QUEUE_DIRECT;
    	bounce_ev.source.client = SNDRV_SEQ_CLIENT_SYSTEM;
    	bounce_ev.source.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
    	bounce_ev.dest.client = client->number;
    	bounce_ev.dest.port = event->source.port;
    	bounce_ev.data.quote.origin = event->dest;
    	bounce_ev.data.quote.event = event;
    	bounce_ev.data.quote.value = -err; /* use positive value */
    	result = snd_seq_deliver_single_event(NULL, &bounce_ev, 0, atomic, hop + 1);
    	if (result < 0) {
    		client->event_lost++;
    		return result;
    	}
    
    	return result;
    }
    
    
    /*
     * rewrite the time-stamp of the event record with the curren time
     * of the given queue.
     * return non-zero if updated.
     */
    static int update_timestamp_of_queue(struct snd_seq_event *event,
    				     int queue, int real_time)
    {
    	struct snd_seq_queue *q;
    
    	q = queueptr(queue);
    	if (! q)
    		return 0;
    	event->queue = queue;
    	event->flags &= ~SNDRV_SEQ_TIME_STAMP_MASK;
    	if (real_time) {
    		event->time.time = snd_seq_timer_get_cur_time(q->timer);
    		event->flags |= SNDRV_SEQ_TIME_STAMP_REAL;
    	} else {
    		event->time.tick = snd_seq_timer_get_cur_tick(q->timer);
    		event->flags |= SNDRV_SEQ_TIME_STAMP_TICK;
    	}
    	queuefree(q);
    	return 1;
    }
    
    
    /*
     * deliver an event to the specified destination.
     * if filter is non-zero, client filter bitmap is tested.
     *
     *  RETURN VALUE: 0 : if succeeded
     *		 <0 : error
     */
    static int snd_seq_deliver_single_event(struct snd_seq_client *client,
    					struct snd_seq_event *event,
    					int filter, int atomic, int hop)
    {
    	struct snd_seq_client *dest = NULL;
    	struct snd_seq_client_port *dest_port = NULL;
    	int result = -ENOENT;
    	int direct;
    
    	direct = snd_seq_ev_is_direct(event);
    
    	dest = get_event_dest_client(event, filter);
    	if (dest == NULL)
    		goto __skip;
    	dest_port = snd_seq_port_use_ptr(dest, event->dest.port);
    	if (dest_port == NULL)
    		goto __skip;
    
    	/* check permission */
    	if (! check_port_perm(dest_port, SNDRV_SEQ_PORT_CAP_WRITE)) {
    		result = -EPERM;
    		goto __skip;
    	}
    		
    	if (dest_port->timestamping)
    		update_timestamp_of_queue(event, dest_port->time_queue,
    					  dest_port->time_real);
    
    	switch (dest->type) {
    	case USER_CLIENT:
    		if (dest->data.user.fifo)
    			result = snd_seq_fifo_event_in(dest->data.user.fifo, event);
    		break;
    
    	case KERNEL_CLIENT:
    		if (dest_port->event_input == NULL)
    			break;
    		result = dest_port->event_input(event, direct,
    						dest_port->private_data,
    						atomic, hop);
    		break;
    	default:
    		break;
    	}
    
      __skip:
    	if (dest_port)
    		snd_seq_port_unlock(dest_port);
    	if (dest)
    		snd_seq_client_unlock(dest);
    
    	if (result < 0 && !direct) {
    		result = bounce_error_event(client, event, result, atomic, hop);
    	}
    	return result;
    }
    
    
    /*
     * send the event to all subscribers:
     */
    static int deliver_to_subscribers(struct snd_seq_client *client,
    				  struct snd_seq_event *event,
    				  int atomic, int hop)
    {
    	struct snd_seq_subscribers *subs;
    	int err, result = 0, num_ev = 0;
    	struct snd_seq_event event_saved;
    	struct snd_seq_client_port *src_port;
    	struct snd_seq_port_subs_info *grp;
    
    	src_port = snd_seq_port_use_ptr(client, event->source.port);
    	if (src_port == NULL)
    		return -EINVAL; /* invalid source port */
    	/* save original event record */
    	event_saved = *event;
    	grp = &src_port->c_src;
    	
    	/* lock list */
    	if (atomic)
    		read_lock(&grp->list_lock);
    	else
    		down_read_nested(&grp->list_mutex, hop);
    	list_for_each_entry(subs, &grp->list_head, src_list) {
    		/* both ports ready? */
    		if (atomic_read(&subs->ref_count) != 2)
    			continue;
    		event->dest = subs->info.dest;
    		if (subs->info.flags & SNDRV_SEQ_PORT_SUBS_TIMESTAMP)
    			/* convert time according to flag with subscription */
    			update_timestamp_of_queue(event, subs->info.queue,
    						  subs->info.flags & SNDRV_SEQ_PORT_SUBS_TIME_REAL);
    		err = snd_seq_deliver_single_event(client, event,
    						   0, atomic, hop);
    		if (err < 0) {
    			/* save first error that occurs and continue */
    			if (!result)
    				result = err;
    			continue;
    		}
    		num_ev++;
    		/* restore original event record */
    		*event = event_saved;
    	}
    	if (atomic)
    		read_unlock(&grp->list_lock);
    	else
    		up_read(&grp->list_mutex);
    	*event = event_saved; /* restore */
    	snd_seq_port_unlock(src_port);
    	return (result < 0) ? result : num_ev;
    }
    
    
    #ifdef SUPPORT_BROADCAST 
    /*
     * broadcast to all ports:
     */
    static int port_broadcast_event(struct snd_seq_client *client,
    				struct snd_seq_event *event,
    				int atomic, int hop)
    {
    	int num_ev = 0, err, result = 0;
    	struct snd_seq_client *dest_client;
    	struct snd_seq_client_port *port;
    
    	dest_client = get_event_dest_client(event, SNDRV_SEQ_FILTER_BROADCAST);
    	if (dest_client == NULL)
    		return 0; /* no matching destination */
    
    	read_lock(&dest_client->ports_lock);
    	list_for_each_entry(port, &dest_client->ports_list_head, list) {
    		event->dest.port = port->addr.port;
    		/* pass NULL as source client to avoid error bounce */
    		err = snd_seq_deliver_single_event(NULL, event,
    						   SNDRV_SEQ_FILTER_BROADCAST,
    						   atomic, hop);
    		if (err < 0) {
    			/* save first error that occurs and continue */
    			if (!result)
    				result = err;
    			continue;
    		}
    		num_ev++;
    	}
    	read_unlock(&dest_client->ports_lock);
    	snd_seq_client_unlock(dest_client);
    	event->dest.port = SNDRV_SEQ_ADDRESS_BROADCAST; /* restore */
    	return (result < 0) ? result : num_ev;
    }
    
    /*
     * send the event to all clients:
     * if destination port is also ADDRESS_BROADCAST, deliver to all ports.
     */
    static int broadcast_event(struct snd_seq_client *client,
    			   struct snd_seq_event *event, int atomic, int hop)
    {
    	int err, result = 0, num_ev = 0;
    	int dest;
    	struct snd_seq_addr addr;
    
    	addr = event->dest; /* save */
    
    	for (dest = 0; dest < SNDRV_SEQ_MAX_CLIENTS; dest++) {
    		/* don't send to itself */
    		if (dest == client->number)
    			continue;
    		event->dest.client = dest;
    		event->dest.port = addr.port;
    		if (addr.port == SNDRV_SEQ_ADDRESS_BROADCAST)
    			err = port_broadcast_event(client, event, atomic, hop);
    		else
    			/* pass NULL as source client to avoid error bounce */
    			err = snd_seq_deliver_single_event(NULL, event,
    							   SNDRV_SEQ_FILTER_BROADCAST,
    							   atomic, hop);
    		if (err < 0) {
    			/* save first error that occurs and continue */
    			if (!result)
    				result = err;
    			continue;
    		}
    		num_ev += err;
    	}
    	event->dest = addr; /* restore */
    	return (result < 0) ? result : num_ev;
    }
    
    
    /* multicast - not supported yet */
    static int multicast_event(struct snd_seq_client *client, struct snd_seq_event *event,
    			   int atomic, int hop)
    {
    	pr_debug("ALSA: seq: multicast not supported yet.\n");
    	return 0; /* ignored */
    }
    #endif /* SUPPORT_BROADCAST */
    
    
    /* deliver an event to the destination port(s).
     * if the event is to subscribers or broadcast, the event is dispatched
     * to multiple targets.
     *
     * RETURN VALUE: n > 0  : the number of delivered events.
     *               n == 0 : the event was not passed to any client.
     *               n < 0  : error - event was not processed.
     */
    static int snd_seq_deliver_event(struct snd_seq_client *client, struct snd_seq_event *event,
    				 int atomic, int hop)
    {
    	int result;
    
    	hop++;
    	if (hop >= SNDRV_SEQ_MAX_HOPS) {
    		pr_debug("ALSA: seq: too long delivery path (%d:%d->%d:%d)\n",
    			   event->source.client, event->source.port,
    			   event->dest.client, event->dest.port);
    		return -EMLINK;
    	}
    
    	if (snd_seq_ev_is_variable(event) &&
    	    snd_BUG_ON(atomic && (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR)))
    		return -EINVAL;
    
    	if (event->queue == SNDRV_SEQ_ADDRESS_SUBSCRIBERS ||
    	    event->dest.client == SNDRV_SEQ_ADDRESS_SUBSCRIBERS)
    		result = deliver_to_subscribers(client, event, atomic, hop);
    #ifdef SUPPORT_BROADCAST
    	else if (event->queue == SNDRV_SEQ_ADDRESS_BROADCAST ||
    		 event->dest.client == SNDRV_SEQ_ADDRESS_BROADCAST)
    		result = broadcast_event(client, event, atomic, hop);
    	else if (event->dest.client >= SNDRV_SEQ_MAX_CLIENTS)
    		result = multicast_event(client, event, atomic, hop);
    	else if (event->dest.port == SNDRV_SEQ_ADDRESS_BROADCAST)
    		result = port_broadcast_event(client, event, atomic, hop);
    #endif
    	else
    		result = snd_seq_deliver_single_event(client, event, 0, atomic, hop);
    
    	return result;
    }
    
    /*
     * dispatch an event cell:
     * This function is called only from queue check routines in timer
     * interrupts or after enqueued.
     * The event cell shall be released or re-queued in this function.
     *
     * RETURN VALUE: n > 0  : the number of delivered events.
     *		 n == 0 : the event was not passed to any client.
     *		 n < 0  : error - event was not processed.
     */
    int snd_seq_dispatch_event(struct snd_seq_event_cell *cell, int atomic, int hop)
    {
    	struct snd_seq_client *client;
    	int result;
    
    	if (snd_BUG_ON(!cell))
    		return -EINVAL;
    
    	client = snd_seq_client_use_ptr(cell->event.source.client);
    	if (client == NULL) {
    		snd_seq_cell_free(cell); /* release this cell */
    		return -EINVAL;
    	}
    
    	if (cell->event.type == SNDRV_SEQ_EVENT_NOTE) {
    		/* NOTE event:
    		 * the event cell is re-used as a NOTE-OFF event and
    		 * enqueued again.
    		 */
    		struct snd_seq_event tmpev, *ev;
    
    		/* reserve this event to enqueue note-off later */
    		tmpev = cell->event;
    		tmpev.type = SNDRV_SEQ_EVENT_NOTEON;
    		result = snd_seq_deliver_event(client, &tmpev, atomic, hop);
    
    		/*
    		 * This was originally a note event.  We now re-use the
    		 * cell for the note-off event.
    		 */
    
    		ev = &cell->event;
    		ev->type = SNDRV_SEQ_EVENT_NOTEOFF;
    		ev->flags |= SNDRV_SEQ_PRIORITY_HIGH;
    
    		/* add the duration time */
    		switch (ev->flags & SNDRV_SEQ_TIME_STAMP_MASK) {
    		case SNDRV_SEQ_TIME_STAMP_TICK:
    			ev->time.tick += ev->data.note.duration;
    			break;
    		case SNDRV_SEQ_TIME_STAMP_REAL:
    			/* unit for duration is ms */
    			ev->time.time.tv_nsec += 1000000 * (ev->data.note.duration % 1000);
    			ev->time.time.tv_sec += ev->data.note.duration / 1000 +
    						ev->time.time.tv_nsec / 1000000000;
    			ev->time.time.tv_nsec %= 1000000000;
    			break;
    		}
    		ev->data.note.velocity = ev->data.note.off_velocity;
    
    		/* Now queue this cell as the note off event */
    		if (snd_seq_enqueue_event(cell, atomic, hop) < 0)
    			snd_seq_cell_free(cell); /* release this cell */
    
    	} else {
    		/* Normal events:
    		 * event cell is freed after processing the event
    		 */
    
    		result = snd_seq_deliver_event(client, &cell->event, atomic, hop);
    		snd_seq_cell_free(cell);
    	}
    
    	snd_seq_client_unlock(client);
    	return result;
    }
    
    
    /* Allocate a cell from client pool and enqueue it to queue:
     * if pool is empty and blocking is TRUE, sleep until a new cell is
     * available.
     */
    static int snd_seq_client_enqueue_event(struct snd_seq_client *client,
    					struct snd_seq_event *event,
    					struct file *file, int blocking,
    					int atomic, int hop)
    {
    	struct snd_seq_event_cell *cell;
    	int err;
    
    	/* special queue values - force direct passing */
    	if (event->queue == SNDRV_SEQ_ADDRESS_SUBSCRIBERS) {
    		event->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
    		event->queue = SNDRV_SEQ_QUEUE_DIRECT;
    	} else
    #ifdef SUPPORT_BROADCAST
    		if (event->queue == SNDRV_SEQ_ADDRESS_BROADCAST) {
    			event->dest.client = SNDRV_SEQ_ADDRESS_BROADCAST;
    			event->queue = SNDRV_SEQ_QUEUE_DIRECT;
    		}
    #endif
    	if (event->dest.client == SNDRV_SEQ_ADDRESS_SUBSCRIBERS) {
    		/* check presence of source port */
    		struct snd_seq_client_port *src_port = snd_seq_port_use_ptr(client, event->source.port);
    		if (src_port == NULL)
    			return -EINVAL;
    		snd_seq_port_unlock(src_port);
    	}
    
    	/* direct event processing without enqueued */
    	if (snd_seq_ev_is_direct(event)) {
    		if (event->type == SNDRV_SEQ_EVENT_NOTE)
    			return -EINVAL; /* this event must be enqueued! */
    		return snd_seq_deliver_event(client, event, atomic, hop);
    	}
    
    	/* Not direct, normal queuing */
    	if (snd_seq_queue_is_used(event->queue, client->number) <= 0)
    		return -EINVAL;  /* invalid queue */
    	if (! snd_seq_write_pool_allocated(client))
    		return -ENXIO; /* queue is not allocated */
    
    	/* allocate an event cell */
    	err = snd_seq_event_dup(client->pool, event, &cell, !blocking || atomic, file);
    	if (err < 0)
    		return err;
    
    	/* we got a cell. enqueue it. */
    	if ((err = snd_seq_enqueue_event(cell, atomic, hop)) < 0) {
    		snd_seq_cell_free(cell);
    		return err;
    	}
    
    	return 0;
    }
    
    
    /*
     * check validity of event type and data length.
     * return non-zero if invalid.
     */
    static int check_event_type_and_length(struct snd_seq_event *ev)
    {
    	switch (snd_seq_ev_length_type(ev)) {
    	case SNDRV_SEQ_EVENT_LENGTH_FIXED:
    		if (snd_seq_ev_is_variable_type(ev))
    			return -EINVAL;
    		break;
    	case SNDRV_SEQ_EVENT_LENGTH_VARIABLE:
    		if (! snd_seq_ev_is_variable_type(ev) ||
    		    (ev->data.ext.len & ~SNDRV_SEQ_EXT_MASK) >= SNDRV_SEQ_MAX_EVENT_LEN)
    			return -EINVAL;
    		break;
    	case SNDRV_SEQ_EVENT_LENGTH_VARUSR:
    		if (! snd_seq_ev_is_direct(ev))
    			return -EINVAL;
    		break;
    	}
    	return 0;
    }
    
    
    /* handle write() */
    /* possible error values:
     *	-ENXIO	invalid client or file open mode
     *	-ENOMEM	malloc failed
     *	-EFAULT	seg. fault during copy from user space
     *	-EINVAL	invalid event
     *	-EAGAIN	no space in output pool
     *	-EINTR	interrupts while sleep
     *	-EMLINK	too many hops
     *	others	depends on return value from driver callback
     */
    static ssize_t snd_seq_write(struct file *file, const char __user *buf,
    			     size_t count, loff_t *offset)
    {
    	struct snd_seq_client *client = file->private_data;
    	int written = 0, len;
    	int err = -EINVAL;
    	struct snd_seq_event event;
    
    	if (!(snd_seq_file_flags(file) & SNDRV_SEQ_LFLG_OUTPUT))
    		return -ENXIO;
    
    	/* check client structures are in place */
    	if (snd_BUG_ON(!client))
    		return -ENXIO;
    		
    	if (!client->accept_output || client->pool == NULL)
    		return -ENXIO;
    
    	/* allocate the pool now if the pool is not allocated yet */ 
    	if (client->pool->size > 0 && !snd_seq_write_pool_allocated(client)) {
    		if (snd_seq_pool_init(client->pool) < 0)
    			return -ENOMEM;
    	}
    
    	/* only process whole events */
    	while (count >= sizeof(struct snd_seq_event)) {
    		/* Read in the event header from the user */
    		len = sizeof(event);
    		if (copy_from_user(&event, buf, len)) {
    			err = -EFAULT;
    			break;
    		}
    		event.source.client = client->number;	/* fill in client number */
    		/* Check for extension data length */
    		if (check_event_type_and_length(&event)) {
    			err = -EINVAL;
    			break;
    		}
    
    		/* check for special events */
    		if (event.type == SNDRV_SEQ_EVENT_NONE)
    			goto __skip_event;
    		else if (snd_seq_ev_is_reserved(&event)) {
    			err = -EINVAL;
    			break;
    		}
    
    		if (snd_seq_ev_is_variable(&event)) {
    			int extlen = event.data.ext.len & ~SNDRV_SEQ_EXT_MASK;
    			if ((size_t)(extlen + len) > count) {
    				/* back out, will get an error this time or next */
    				err = -EINVAL;
    				break;
    			}
    			/* set user space pointer */
    			event.data.ext.len = extlen | SNDRV_SEQ_EXT_USRPTR;
    			event.data.ext.ptr = (char __force *)buf
    						+ sizeof(struct snd_seq_event);
    			len += extlen; /* increment data length */
    		} else {
    #ifdef CONFIG_COMPAT
    			if (client->convert32 && snd_seq_ev_is_varusr(&event)) {
    				void *ptr = (void __force *)compat_ptr(event.data.raw32.d[1]);
    				event.data.ext.ptr = ptr;
    			}
    #endif
    		}
    
    		/* ok, enqueue it */
    		err = snd_seq_client_enqueue_event(client, &event, file,
    						   !(file->f_flags & O_NONBLOCK),
    						   0, 0);
    		if (err < 0)
    			break;
    
    	__skip_event:
    		/* Update pointers and counts */
    		count -= len;
    		buf += len;
    		written += len;
    	}
    
    	return written ? written : err;
    }
    
    
    /*
     * handle polling
     */
    static unsigned int snd_seq_poll(struct file *file, poll_table * wait)
    {
    	struct snd_seq_client *client = file->private_data;
    	unsigned int mask = 0;
    
    	/* check client structures are in place */
    	if (snd_BUG_ON(!client))
    		return -ENXIO;
    
    	if ((snd_seq_file_flags(file) & SNDRV_SEQ_LFLG_INPUT) &&
    	    client->data.user.fifo) {
    
    		/* check if data is available in the outqueue */
    		if (snd_seq_fifo_poll_wait(client->data.user.fifo, file, wait))
    			mask |= POLLIN | POLLRDNORM;
    	}
    
    	if (snd_seq_file_flags(file) & SNDRV_SEQ_LFLG_OUTPUT) {
    
    		/* check if data is available in the pool */
    		if (!snd_seq_write_pool_allocated(client) ||
    		    snd_seq_pool_poll_wait(client->pool, file, wait))
    			mask |= POLLOUT | POLLWRNORM;
    	}
    
    	return mask;
    }
    
    
    /*-----------------------------------------------------*/
    
    static int snd_seq_ioctl_pversion(struct snd_seq_client *client, void *arg)
    {
    	int *pversion = arg;
    
    	*pversion = SNDRV_SEQ_VERSION;
    	return 0;
    }
    
    static int snd_seq_ioctl_client_id(struct snd_seq_client *client, void *arg)
    {
    	int *client_id = arg;
    
    	*client_id = client->number;
    	return 0;
    }
    
    /* SYSTEM_INFO ioctl() */
    static int snd_seq_ioctl_system_info(struct snd_seq_client *client, void *arg)
    {
    	struct snd_seq_system_info *info = arg;
    
    	memset(info, 0, sizeof(*info));
    	/* fill the info fields */
    	info->queues = SNDRV_SEQ_MAX_QUEUES;
    	info->clients = SNDRV_SEQ_MAX_CLIENTS;
    	info->ports = SNDRV_SEQ_MAX_PORTS;
    	info->channels = 256;	/* fixed limit */
    	info->cur_clients = client_usage.cur;
    	info->cur_queues = snd_seq_queue_get_cur_queues();
    
    	return 0;
    }
    
    
    /* RUNNING_MODE ioctl() */
    static int snd_seq_ioctl_running_mode(struct snd_seq_client *client, void  *arg)
    {
    	struct snd_seq_running_info *info = arg;
    	struct snd_seq_client *cptr;
    	int err = 0;
    
    	/* requested client number */
    	cptr = snd_seq_client_use_ptr(info->client);
    	if (cptr == NULL)
    		return -ENOENT;		/* don't change !!! */
    
    #ifdef SNDRV_BIG_ENDIAN
    	if (!info->big_endian) {
    		err = -EINVAL;
    		goto __err;
    	}
    #else
    	if (info->big_endian) {
    		err = -EINVAL;
    		goto __err;
    	}
    
    #endif
    	if (info->cpu_mode > sizeof(long)) {
    		err = -EINVAL;
    		goto __err;
    	}
    	cptr->convert32 = (info->cpu_mode < sizeof(long));
     __err:
    	snd_seq_client_unlock(cptr);
    	return err;
    }
    
    /* CLIENT_INFO ioctl() */
    static void get_client_info(struct snd_seq_client *cptr,
    			    struct snd_seq_client_info *info)
    {
    	info->client = cptr->number;
    
    	/* fill the info fields */
    	info->type = cptr->type;
    	strcpy(info->name, cptr->name);
    	info->filter = cptr->filter;
    	info->event_lost = cptr->event_lost;
    	memcpy(info->event_filter, cptr->event_filter, 32);
    	info->num_ports = cptr->num_ports;
    
    	if (cptr->type == USER_CLIENT)
    		info->pid = pid_vnr(cptr->data.user.owner);
    	else
    		info->pid = -1;
    
    	if (cptr->type == KERNEL_CLIENT)
    		info->card = cptr->data.kernel.card ? cptr->data.kernel.card->number : -1;
    	else
    		info->card = -1;
    
    	memset(info->reserved, 0, sizeof(info->reserved));
    }
    
    static int snd_seq_ioctl_get_client_info(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_client_info *client_info = arg;
    	struct snd_seq_client *cptr;
    
    	/* requested client number */
    	cptr = snd_seq_client_use_ptr(client_info->client);
    	if (cptr == NULL)
    		return -ENOENT;		/* don't change !!! */
    
    	get_client_info(cptr, client_info);
    	snd_seq_client_unlock(cptr);
    
    	return 0;
    }
    
    
    /* CLIENT_INFO ioctl() */
    static int snd_seq_ioctl_set_client_info(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_client_info *client_info = arg;
    
    	/* it is not allowed to set the info fields for an another client */
    	if (client->number != client_info->client)
    		return -EPERM;
    	/* also client type must be set now */
    	if (client->type != client_info->type)
    		return -EINVAL;
    
    	/* fill the info fields */
    	if (client_info->name[0])
    		strlcpy(client->name, client_info->name, sizeof(client->name));
    
    	client->filter = client_info->filter;
    	client->event_lost = client_info->event_lost;
    	memcpy(client->event_filter, client_info->event_filter, 32);
    
    	return 0;
    }
    
    
    /* 
     * CREATE PORT ioctl() 
     */
    static int snd_seq_ioctl_create_port(struct snd_seq_client *client, void *arg)
    {
    	struct snd_seq_port_info *info = arg;
    	struct snd_seq_client_port *port;
    	struct snd_seq_port_callback *callback;
    	int port_idx;
    
    	/* it is not allowed to create the port for an another client */
    	if (info->addr.client != client->number)
    		return -EPERM;
    
    	port = snd_seq_create_port(client, (info->flags & SNDRV_SEQ_PORT_FLG_GIVEN_PORT) ? info->addr.port : -1);
    	if (port == NULL)
    		return -ENOMEM;
    
    	if (client->type == USER_CLIENT && info->kernel) {
    		port_idx = port->addr.port;
    		snd_seq_port_unlock(port);
    		snd_seq_delete_port(client, port_idx);
    		return -EINVAL;
    	}
    	if (client->type == KERNEL_CLIENT) {
    		if ((callback = info->kernel) != NULL) {
    			if (callback->owner)
    				port->owner = callback->owner;
    			port->private_data = callback->private_data;
    			port->private_free = callback->private_free;
    			port->event_input = callback->event_input;
    			port->c_src.open = callback->subscribe;
    			port->c_src.close = callback->unsubscribe;
    			port->c_dest.open = callback->use;
    			port->c_dest.close = callback->unuse;
    		}
    	}
    
    	info->addr = port->addr;
    
    	snd_seq_set_port_info(port, info);
    	snd_seq_system_client_ev_port_start(port->addr.client, port->addr.port);
    	snd_seq_port_unlock(port);
    
    	return 0;
    }
    
    /* 
     * DELETE PORT ioctl() 
     */
    static int snd_seq_ioctl_delete_port(struct snd_seq_client *client, void *arg)
    {
    	struct snd_seq_port_info *info = arg;
    	int err;
    
    	/* it is not allowed to remove the port for an another client */
    	if (info->addr.client != client->number)
    		return -EPERM;
    
    	err = snd_seq_delete_port(client, info->addr.port);
    	if (err >= 0)
    		snd_seq_system_client_ev_port_exit(client->number, info->addr.port);
    	return err;
    }
    
    
    /* 
     * GET_PORT_INFO ioctl() (on any client) 
     */
    static int snd_seq_ioctl_get_port_info(struct snd_seq_client *client, void *arg)
    {
    	struct snd_seq_port_info *info = arg;
    	struct snd_seq_client *cptr;
    	struct snd_seq_client_port *port;
    
    	cptr = snd_seq_client_use_ptr(info->addr.client);
    	if (cptr == NULL)
    		return -ENXIO;
    
    	port = snd_seq_port_use_ptr(cptr, info->addr.port);
    	if (port == NULL) {
    		snd_seq_client_unlock(cptr);
    		return -ENOENT;			/* don't change */
    	}
    
    	/* get port info */
    	snd_seq_get_port_info(port, info);
    	snd_seq_port_unlock(port);
    	snd_seq_client_unlock(cptr);
    
    	return 0;
    }
    
    
    /* 
     * SET_PORT_INFO ioctl() (only ports on this/own client) 
     */
    static int snd_seq_ioctl_set_port_info(struct snd_seq_client *client, void *arg)
    {
    	struct snd_seq_port_info *info = arg;
    	struct snd_seq_client_port *port;
    
    	if (info->addr.client != client->number) /* only set our own ports ! */
    		return -EPERM;
    	port = snd_seq_port_use_ptr(client, info->addr.port);
    	if (port) {
    		snd_seq_set_port_info(port, info);
    		snd_seq_port_unlock(port);
    	}
    	return 0;
    }
    
    
    /*
     * port subscription (connection)
     */
    #define PERM_RD		(SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ)
    #define PERM_WR		(SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_SUBS_WRITE)
    
    static int check_subscription_permission(struct snd_seq_client *client,
    					 struct snd_seq_client_port *sport,
    					 struct snd_seq_client_port *dport,
    					 struct snd_seq_port_subscribe *subs)
    {
    	if (client->number != subs->sender.client &&
    	    client->number != subs->dest.client) {
    		/* connection by third client - check export permission */
    		if (check_port_perm(sport, SNDRV_SEQ_PORT_CAP_NO_EXPORT))
    			return -EPERM;
    		if (check_port_perm(dport, SNDRV_SEQ_PORT_CAP_NO_EXPORT))
    			return -EPERM;
    	}
    
    	/* check read permission */
    	/* if sender or receiver is the subscribing client itself,
    	 * no permission check is necessary
    	 */
    	if (client->number != subs->sender.client) {
    		if (! check_port_perm(sport, PERM_RD))
    			return -EPERM;
    	}
    	/* check write permission */
    	if (client->number != subs->dest.client) {
    		if (! check_port_perm(dport, PERM_WR))
    			return -EPERM;
    	}
    	return 0;
    }
    
    /*
     * send an subscription notify event to user client:
     * client must be user client.
     */
    int snd_seq_client_notify_subscription(int client, int port,
    				       struct snd_seq_port_subscribe *info,
    				       int evtype)
    {
    	struct snd_seq_event event;
    
    	memset(&event, 0, sizeof(event));
    	event.type = evtype;
    	event.data.connect.dest = info->dest;
    	event.data.connect.sender = info->sender;
    
    	return snd_seq_system_notify(client, port, &event);  /* non-atomic */
    }
    
    
    /* 
     * add to port's subscription list IOCTL interface 
     */
    static int snd_seq_ioctl_subscribe_port(struct snd_seq_client *client,
    					void *arg)
    {
    	struct snd_seq_port_subscribe *subs = arg;
    	int result = -EINVAL;
    	struct snd_seq_client *receiver = NULL, *sender = NULL;
    	struct snd_seq_client_port *sport = NULL, *dport = NULL;
    
    	if ((receiver = snd_seq_client_use_ptr(subs->dest.client)) == NULL)
    		goto __end;
    	if ((sender = snd_seq_client_use_ptr(subs->sender.client)) == NULL)
    		goto __end;
    	if ((sport = snd_seq_port_use_ptr(sender, subs->sender.port)) == NULL)
    		goto __end;
    	if ((dport = snd_seq_port_use_ptr(receiver, subs->dest.port)) == NULL)
    		goto __end;
    
    	result = check_subscription_permission(client, sport, dport, subs);
    	if (result < 0)
    		goto __end;
    
    	/* connect them */
    	result = snd_seq_port_connect(client, sender, sport, receiver, dport, subs);
    	if (! result) /* broadcast announce */
    		snd_seq_client_notify_subscription(SNDRV_SEQ_ADDRESS_SUBSCRIBERS, 0,
    						   subs, SNDRV_SEQ_EVENT_PORT_SUBSCRIBED);
          __end:
          	if (sport)
    		snd_seq_port_unlock(sport);
    	if (dport)
    		snd_seq_port_unlock(dport);
    	if (sender)
    		snd_seq_client_unlock(sender);
    	if (receiver)
    		snd_seq_client_unlock(receiver);
    	return result;
    }
    
    
    /* 
     * remove from port's subscription list 
     */
    static int snd_seq_ioctl_unsubscribe_port(struct snd_seq_client *client,
    					  void *arg)
    {
    	struct snd_seq_port_subscribe *subs = arg;
    	int result = -ENXIO;
    	struct snd_seq_client *receiver = NULL, *sender = NULL;
    	struct snd_seq_client_port *sport = NULL, *dport = NULL;
    
    	if ((receiver = snd_seq_client_use_ptr(subs->dest.client)) == NULL)
    		goto __end;
    	if ((sender = snd_seq_client_use_ptr(subs->sender.client)) == NULL)
    		goto __end;
    	if ((sport = snd_seq_port_use_ptr(sender, subs->sender.port)) == NULL)
    		goto __end;
    	if ((dport = snd_seq_port_use_ptr(receiver, subs->dest.port)) == NULL)
    		goto __end;
    
    	result = check_subscription_permission(client, sport, dport, subs);
    	if (result < 0)
    		goto __end;
    
    	result = snd_seq_port_disconnect(client, sender, sport, receiver, dport, subs);
    	if (! result) /* broadcast announce */
    		snd_seq_client_notify_subscription(SNDRV_SEQ_ADDRESS_SUBSCRIBERS, 0,
    						   subs, SNDRV_SEQ_EVENT_PORT_UNSUBSCRIBED);
          __end:
          	if (sport)
    		snd_seq_port_unlock(sport);
    	if (dport)
    		snd_seq_port_unlock(dport);
    	if (sender)
    		snd_seq_client_unlock(sender);
    	if (receiver)
    		snd_seq_client_unlock(receiver);
    	return result;
    }
    
    
    /* CREATE_QUEUE ioctl() */
    static int snd_seq_ioctl_create_queue(struct snd_seq_client *client, void *arg)
    {
    	struct snd_seq_queue_info *info = arg;
    	struct snd_seq_queue *q;
    
    	q = snd_seq_queue_alloc(client->number, info->locked, info->flags);
    	if (IS_ERR(q))
    		return PTR_ERR(q);
    
    	info->queue = q->queue;
    	info->locked = q->locked;
    	info->owner = q->owner;
    
    	/* set queue name */
    	if (!info->name[0])
    		snprintf(info->name, sizeof(info->name), "Queue-%d", q->queue);
    	strlcpy(q->name, info->name, sizeof(q->name));
    	snd_use_lock_free(&q->use_lock);
    
    	return 0;
    }
    
    /* DELETE_QUEUE ioctl() */
    static int snd_seq_ioctl_delete_queue(struct snd_seq_client *client, void *arg)
    {
    	struct snd_seq_queue_info *info = arg;
    
    	return snd_seq_queue_delete(client->number, info->queue);
    }
    
    /* GET_QUEUE_INFO ioctl() */
    static int snd_seq_ioctl_get_queue_info(struct snd_seq_client *client,
    					void *arg)
    {
    	struct snd_seq_queue_info *info = arg;
    	struct snd_seq_queue *q;
    
    	q = queueptr(info->queue);
    	if (q == NULL)
    		return -EINVAL;
    
    	memset(info, 0, sizeof(*info));
    	info->queue = q->queue;
    	info->owner = q->owner;
    	info->locked = q->locked;
    	strlcpy(info->name, q->name, sizeof(info->name));
    	queuefree(q);
    
    	return 0;
    }
    
    /* SET_QUEUE_INFO ioctl() */
    static int snd_seq_ioctl_set_queue_info(struct snd_seq_client *client,
    					void *arg)
    {
    	struct snd_seq_queue_info *info = arg;
    	struct snd_seq_queue *q;
    
    	if (info->owner != client->number)
    		return -EINVAL;
    
    	/* change owner/locked permission */
    	if (snd_seq_queue_check_access(info->queue, client->number)) {
    		if (snd_seq_queue_set_owner(info->queue, client->number, info->locked) < 0)
    			return -EPERM;
    		if (info->locked)
    			snd_seq_queue_use(info->queue, client->number, 1);
    	} else {
    		return -EPERM;
    	}	
    
    	q = queueptr(info->queue);
    	if (! q)
    		return -EINVAL;
    	if (q->owner != client->number) {
    		queuefree(q);
    		return -EPERM;
    	}
    	strlcpy(q->name, info->name, sizeof(q->name));
    	queuefree(q);
    
    	return 0;
    }
    
    /* GET_NAMED_QUEUE ioctl() */
    static int snd_seq_ioctl_get_named_queue(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_queue_info *info = arg;
    	struct snd_seq_queue *q;
    
    	q = snd_seq_queue_find_name(info->name);
    	if (q == NULL)
    		return -EINVAL;
    	info->queue = q->queue;
    	info->owner = q->owner;
    	info->locked = q->locked;
    	queuefree(q);
    
    	return 0;
    }
    
    /* GET_QUEUE_STATUS ioctl() */
    static int snd_seq_ioctl_get_queue_status(struct snd_seq_client *client,
    					  void *arg)
    {
    	struct snd_seq_queue_status *status = arg;
    	struct snd_seq_queue *queue;
    	struct snd_seq_timer *tmr;
    
    	queue = queueptr(status->queue);
    	if (queue == NULL)
    		return -EINVAL;
    	memset(status, 0, sizeof(*status));
    	status->queue = queue->queue;
    	
    	tmr = queue->timer;
    	status->events = queue->tickq->cells + queue->timeq->cells;
    
    	status->time = snd_seq_timer_get_cur_time(tmr);
    	status->tick = snd_seq_timer_get_cur_tick(tmr);
    
    	status->running = tmr->running;
    
    	status->flags = queue->flags;
    	queuefree(queue);
    
    	return 0;
    }
    
    
    /* GET_QUEUE_TEMPO ioctl() */
    static int snd_seq_ioctl_get_queue_tempo(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_queue_tempo *tempo = arg;
    	struct snd_seq_queue *queue;
    	struct snd_seq_timer *tmr;
    
    	queue = queueptr(tempo->queue);
    	if (queue == NULL)
    		return -EINVAL;
    	memset(tempo, 0, sizeof(*tempo));
    	tempo->queue = queue->queue;
    	
    	tmr = queue->timer;
    
    	tempo->tempo = tmr->tempo;
    	tempo->ppq = tmr->ppq;
    	tempo->skew_value = tmr->skew;
    	tempo->skew_base = tmr->skew_base;
    	queuefree(queue);
    
    	return 0;
    }
    
    
    /* SET_QUEUE_TEMPO ioctl() */
    int snd_seq_set_queue_tempo(int client, struct snd_seq_queue_tempo *tempo)
    {
    	if (!snd_seq_queue_check_access(tempo->queue, client))
    		return -EPERM;
    	return snd_seq_queue_timer_set_tempo(tempo->queue, client, tempo);
    }
    EXPORT_SYMBOL(snd_seq_set_queue_tempo);
    
    static int snd_seq_ioctl_set_queue_tempo(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_queue_tempo *tempo = arg;
    	int result;
    
    	result = snd_seq_set_queue_tempo(client->number, tempo);
    	return result < 0 ? result : 0;
    }
    
    
    /* GET_QUEUE_TIMER ioctl() */
    static int snd_seq_ioctl_get_queue_timer(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_queue_timer *timer = arg;
    	struct snd_seq_queue *queue;
    	struct snd_seq_timer *tmr;
    
    	queue = queueptr(timer->queue);
    	if (queue == NULL)
    		return -EINVAL;
    
    	if (mutex_lock_interruptible(&queue->timer_mutex)) {
    		queuefree(queue);
    		return -ERESTARTSYS;
    	}
    	tmr = queue->timer;
    	memset(timer, 0, sizeof(*timer));
    	timer->queue = queue->queue;
    
    	timer->type = tmr->type;
    	if (tmr->type == SNDRV_SEQ_TIMER_ALSA) {
    		timer->u.alsa.id = tmr->alsa_id;
    		timer->u.alsa.resolution = tmr->preferred_resolution;
    	}
    	mutex_unlock(&queue->timer_mutex);
    	queuefree(queue);
    	
    	return 0;
    }
    
    
    /* SET_QUEUE_TIMER ioctl() */
    static int snd_seq_ioctl_set_queue_timer(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_queue_timer *timer = arg;
    	int result = 0;
    
    	if (timer->type != SNDRV_SEQ_TIMER_ALSA)
    		return -EINVAL;
    
    	if (snd_seq_queue_check_access(timer->queue, client->number)) {
    		struct snd_seq_queue *q;
    		struct snd_seq_timer *tmr;
    
    		q = queueptr(timer->queue);
    		if (q == NULL)
    			return -ENXIO;
    		if (mutex_lock_interruptible(&q->timer_mutex)) {
    			queuefree(q);
    			return -ERESTARTSYS;
    		}
    		tmr = q->timer;
    		snd_seq_queue_timer_close(timer->queue);
    		tmr->type = timer->type;
    		if (tmr->type == SNDRV_SEQ_TIMER_ALSA) {
    			tmr->alsa_id = timer->u.alsa.id;
    			tmr->preferred_resolution = timer->u.alsa.resolution;
    		}
    		result = snd_seq_queue_timer_open(timer->queue);
    		mutex_unlock(&q->timer_mutex);
    		queuefree(q);
    	} else {
    		return -EPERM;
    	}	
    
    	return result;
    }
    
    
    /* GET_QUEUE_CLIENT ioctl() */
    static int snd_seq_ioctl_get_queue_client(struct snd_seq_client *client,
    					  void *arg)
    {
    	struct snd_seq_queue_client *info = arg;
    	int used;
    
    	used = snd_seq_queue_is_used(info->queue, client->number);
    	if (used < 0)
    		return -EINVAL;
    	info->used = used;
    	info->client = client->number;
    
    	return 0;
    }
    
    
    /* SET_QUEUE_CLIENT ioctl() */
    static int snd_seq_ioctl_set_queue_client(struct snd_seq_client *client,
    					  void *arg)
    {
    	struct snd_seq_queue_client *info = arg;
    	int err;
    
    	if (info->used >= 0) {
    		err = snd_seq_queue_use(info->queue, client->number, info->used);
    		if (err < 0)
    			return err;
    	}
    
    	return snd_seq_ioctl_get_queue_client(client, arg);
    }
    
    
    /* GET_CLIENT_POOL ioctl() */
    static int snd_seq_ioctl_get_client_pool(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_client_pool *info = arg;
    	struct snd_seq_client *cptr;
    
    	cptr = snd_seq_client_use_ptr(info->client);
    	if (cptr == NULL)
    		return -ENOENT;
    	memset(info, 0, sizeof(*info));
    	info->client = cptr->number;
    	info->output_pool = cptr->pool->size;
    	info->output_room = cptr->pool->room;
    	info->output_free = info->output_pool;
    	info->output_free = snd_seq_unused_cells(cptr->pool);
    	if (cptr->type == USER_CLIENT) {
    		info->input_pool = cptr->data.user.fifo_pool_size;
    		info->input_free = info->input_pool;
    		if (cptr->data.user.fifo)
    			info->input_free = snd_seq_unused_cells(cptr->data.user.fifo->pool);
    	} else {
    		info->input_pool = 0;
    		info->input_free = 0;
    	}
    	snd_seq_client_unlock(cptr);
    	
    	return 0;
    }
    
    /* SET_CLIENT_POOL ioctl() */
    static int snd_seq_ioctl_set_client_pool(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_client_pool *info = arg;
    	int rc;
    
    	if (client->number != info->client)
    		return -EINVAL; /* can't change other clients */
    
    	if (info->output_pool >= 1 && info->output_pool <= SNDRV_SEQ_MAX_EVENTS &&
    	    (! snd_seq_write_pool_allocated(client) ||
    	     info->output_pool != client->pool->size)) {
    		if (snd_seq_write_pool_allocated(client)) {
    			/* remove all existing cells */
    			snd_seq_pool_mark_closing(client->pool);
    			snd_seq_queue_client_leave_cells(client->number);
    			snd_seq_pool_done(client->pool);
    		}
    		client->pool->size = info->output_pool;
    		rc = snd_seq_pool_init(client->pool);
    		if (rc < 0)
    			return rc;
    	}
    	if (client->type == USER_CLIENT && client->data.user.fifo != NULL &&
    	    info->input_pool >= 1 &&
    	    info->input_pool <= SNDRV_SEQ_MAX_CLIENT_EVENTS &&
    	    info->input_pool != client->data.user.fifo_pool_size) {
    		/* change pool size */
    		rc = snd_seq_fifo_resize(client->data.user.fifo, info->input_pool);
    		if (rc < 0)
    			return rc;
    		client->data.user.fifo_pool_size = info->input_pool;
    	}
    	if (info->output_room >= 1 &&
    	    info->output_room <= client->pool->size) {
    		client->pool->room  = info->output_room;
    	}
    
    	return snd_seq_ioctl_get_client_pool(client, arg);
    }
    
    
    /* REMOVE_EVENTS ioctl() */
    static int snd_seq_ioctl_remove_events(struct snd_seq_client *client,
    				       void *arg)
    {
    	struct snd_seq_remove_events *info = arg;
    
    	/*
    	 * Input mostly not implemented XXX.
    	 */
    	if (info->remove_mode & SNDRV_SEQ_REMOVE_INPUT) {
    		/*
    		 * No restrictions so for a user client we can clear
    		 * the whole fifo
    		 */
    		if (client->type == USER_CLIENT && client->data.user.fifo)
    			snd_seq_fifo_clear(client->data.user.fifo);
    	}
    
    	if (info->remove_mode & SNDRV_SEQ_REMOVE_OUTPUT)
    		snd_seq_queue_remove_cells(client->number, info);
    
    	return 0;
    }
    
    
    /*
     * get subscription info
     */
    static int snd_seq_ioctl_get_subscription(struct snd_seq_client *client,
    					  void *arg)
    {
    	struct snd_seq_port_subscribe *subs = arg;
    	int result;
    	struct snd_seq_client *sender = NULL;
    	struct snd_seq_client_port *sport = NULL;
    	struct snd_seq_subscribers *p;
    
    	result = -EINVAL;
    	if ((sender = snd_seq_client_use_ptr(subs->sender.client)) == NULL)
    		goto __end;
    	if ((sport = snd_seq_port_use_ptr(sender, subs->sender.port)) == NULL)
    		goto __end;
    	p = snd_seq_port_get_subscription(&sport->c_src, &subs->dest);
    	if (p) {
    		result = 0;
    		*subs = p->info;
    	} else
    		result = -ENOENT;
    
          __end:
          	if (sport)
    		snd_seq_port_unlock(sport);
    	if (sender)
    		snd_seq_client_unlock(sender);
    
    	return result;
    }
    
    
    /*
     * get subscription info - check only its presence
     */
    static int snd_seq_ioctl_query_subs(struct snd_seq_client *client, void *arg)
    {
    	struct snd_seq_query_subs *subs = arg;
    	int result = -ENXIO;
    	struct snd_seq_client *cptr = NULL;
    	struct snd_seq_client_port *port = NULL;
    	struct snd_seq_port_subs_info *group;
    	struct list_head *p;
    	int i;
    
    	if ((cptr = snd_seq_client_use_ptr(subs->root.client)) == NULL)
    		goto __end;
    	if ((port = snd_seq_port_use_ptr(cptr, subs->root.port)) == NULL)
    		goto __end;
    
    	switch (subs->type) {
    	case SNDRV_SEQ_QUERY_SUBS_READ:
    		group = &port->c_src;
    		break;
    	case SNDRV_SEQ_QUERY_SUBS_WRITE:
    		group = &port->c_dest;
    		break;
    	default:
    		goto __end;
    	}
    
    	down_read(&group->list_mutex);
    	/* search for the subscriber */
    	subs->num_subs = group->count;
    	i = 0;
    	result = -ENOENT;
    	list_for_each(p, &group->list_head) {
    		if (i++ == subs->index) {
    			/* found! */
    			struct snd_seq_subscribers *s;
    			if (subs->type == SNDRV_SEQ_QUERY_SUBS_READ) {
    				s = list_entry(p, struct snd_seq_subscribers, src_list);
    				subs->addr = s->info.dest;
    			} else {
    				s = list_entry(p, struct snd_seq_subscribers, dest_list);
    				subs->addr = s->info.sender;
    			}
    			subs->flags = s->info.flags;
    			subs->queue = s->info.queue;
    			result = 0;
    			break;
    		}
    	}
    	up_read(&group->list_mutex);
    
          __end:
       	if (port)
    		snd_seq_port_unlock(port);
    	if (cptr)
    		snd_seq_client_unlock(cptr);
    
    	return result;
    }
    
    
    /*
     * query next client
     */
    static int snd_seq_ioctl_query_next_client(struct snd_seq_client *client,
    					   void *arg)
    {
    	struct snd_seq_client_info *info = arg;
    	struct snd_seq_client *cptr = NULL;
    
    	/* search for next client */
    	info->client++;
    	if (info->client < 0)
    		info->client = 0;
    	for (; info->client < SNDRV_SEQ_MAX_CLIENTS; info->client++) {
    		cptr = snd_seq_client_use_ptr(info->client);
    		if (cptr)
    			break; /* found */
    	}
    	if (cptr == NULL)
    		return -ENOENT;
    
    	get_client_info(cptr, info);
    	snd_seq_client_unlock(cptr);
    
    	return 0;
    }
    
    /* 
     * query next port
     */
    static int snd_seq_ioctl_query_next_port(struct snd_seq_client *client,
    					 void *arg)
    {
    	struct snd_seq_port_info *info = arg;
    	struct snd_seq_client *cptr;
    	struct snd_seq_client_port *port = NULL;
    
    	cptr = snd_seq_client_use_ptr(info->addr.client);
    	if (cptr == NULL)
    		return -ENXIO;
    
    	/* search for next port */
    	info->addr.port++;
    	port = snd_seq_port_query_nearest(cptr, info);
    	if (port == NULL) {
    		snd_seq_client_unlock(cptr);
    		return -ENOENT;
    	}
    
    	/* get port info */
    	info->addr = port->addr;
    	snd_seq_get_port_info(port, info);
    	snd_seq_port_unlock(port);
    	snd_seq_client_unlock(cptr);
    
    	return 0;
    }
    
    /* -------------------------------------------------------- */
    
    static const struct ioctl_handler {
    	unsigned int cmd;
    	int (*func)(struct snd_seq_client *client, void *arg);
    } ioctl_handlers[] = {
    	{ SNDRV_SEQ_IOCTL_PVERSION, snd_seq_ioctl_pversion },
    	{ SNDRV_SEQ_IOCTL_CLIENT_ID, snd_seq_ioctl_client_id },
    	{ SNDRV_SEQ_IOCTL_SYSTEM_INFO, snd_seq_ioctl_system_info },
    	{ SNDRV_SEQ_IOCTL_RUNNING_MODE, snd_seq_ioctl_running_mode },
    	{ SNDRV_SEQ_IOCTL_GET_CLIENT_INFO, snd_seq_ioctl_get_client_info },
    	{ SNDRV_SEQ_IOCTL_SET_CLIENT_INFO, snd_seq_ioctl_set_client_info },
    	{ SNDRV_SEQ_IOCTL_CREATE_PORT, snd_seq_ioctl_create_port },
    	{ SNDRV_SEQ_IOCTL_DELETE_PORT, snd_seq_ioctl_delete_port },
    	{ SNDRV_SEQ_IOCTL_GET_PORT_INFO, snd_seq_ioctl_get_port_info },
    	{ SNDRV_SEQ_IOCTL_SET_PORT_INFO, snd_seq_ioctl_set_port_info },
    	{ SNDRV_SEQ_IOCTL_SUBSCRIBE_PORT, snd_seq_ioctl_subscribe_port },
    	{ SNDRV_SEQ_IOCTL_UNSUBSCRIBE_PORT, snd_seq_ioctl_unsubscribe_port },
    	{ SNDRV_SEQ_IOCTL_CREATE_QUEUE, snd_seq_ioctl_create_queue },
    	{ SNDRV_SEQ_IOCTL_DELETE_QUEUE, snd_seq_ioctl_delete_queue },
    	{ SNDRV_SEQ_IOCTL_GET_QUEUE_INFO, snd_seq_ioctl_get_queue_info },
    	{ SNDRV_SEQ_IOCTL_SET_QUEUE_INFO, snd_seq_ioctl_set_queue_info },
    	{ SNDRV_SEQ_IOCTL_GET_NAMED_QUEUE, snd_seq_ioctl_get_named_queue },
    	{ SNDRV_SEQ_IOCTL_GET_QUEUE_STATUS, snd_seq_ioctl_get_queue_status },
    	{ SNDRV_SEQ_IOCTL_GET_QUEUE_TEMPO, snd_seq_ioctl_get_queue_tempo },
    	{ SNDRV_SEQ_IOCTL_SET_QUEUE_TEMPO, snd_seq_ioctl_set_queue_tempo },
    	{ SNDRV_SEQ_IOCTL_GET_QUEUE_TIMER, snd_seq_ioctl_get_queue_timer },
    	{ SNDRV_SEQ_IOCTL_SET_QUEUE_TIMER, snd_seq_ioctl_set_queue_timer },
    	{ SNDRV_SEQ_IOCTL_GET_QUEUE_CLIENT, snd_seq_ioctl_get_queue_client },
    	{ SNDRV_SEQ_IOCTL_SET_QUEUE_CLIENT, snd_seq_ioctl_set_queue_client },
    	{ SNDRV_SEQ_IOCTL_GET_CLIENT_POOL, snd_seq_ioctl_get_client_pool },
    	{ SNDRV_SEQ_IOCTL_SET_CLIENT_POOL, snd_seq_ioctl_set_client_pool },
    	{ SNDRV_SEQ_IOCTL_GET_SUBSCRIPTION, snd_seq_ioctl_get_subscription },
    	{ SNDRV_SEQ_IOCTL_QUERY_NEXT_CLIENT, snd_seq_ioctl_query_next_client },
    	{ SNDRV_SEQ_IOCTL_QUERY_NEXT_PORT, snd_seq_ioctl_query_next_port },
    	{ SNDRV_SEQ_IOCTL_REMOVE_EVENTS, snd_seq_ioctl_remove_events },
    	{ SNDRV_SEQ_IOCTL_QUERY_SUBS, snd_seq_ioctl_query_subs },
    	{ 0, NULL },
    };
    
    static long snd_seq_ioctl(struct file *file, unsigned int cmd,
    			  unsigned long arg)
    {
    	struct snd_seq_client *client = file->private_data;
    	/* To use kernel stack for ioctl data. */
    	union {
    		int pversion;
    		int client_id;
    		struct snd_seq_system_info	system_info;
    		struct snd_seq_running_info	running_info;
    		struct snd_seq_client_info	client_info;
    		struct snd_seq_port_info	port_info;
    		struct snd_seq_port_subscribe	port_subscribe;
    		struct snd_seq_queue_info	queue_info;
    		struct snd_seq_queue_status	queue_status;
    		struct snd_seq_queue_tempo	tempo;
    		struct snd_seq_queue_timer	queue_timer;
    		struct snd_seq_queue_client	queue_client;
    		struct snd_seq_client_pool	client_pool;
    		struct snd_seq_remove_events	remove_events;
    		struct snd_seq_query_subs	query_subs;
    	} buf;
    	const struct ioctl_handler *handler;
    	unsigned long size;
    	int err;
    
    	if (snd_BUG_ON(!client))
    		return -ENXIO;
    
    	for (handler = ioctl_handlers; handler->cmd > 0; ++handler) {
    		if (handler->cmd == cmd)
    			break;
    	}
    	if (handler->cmd == 0)
    		return -ENOTTY;
    
    	memset(&buf, 0, sizeof(buf));
    
    	/*
    	 * All of ioctl commands for ALSA sequencer get an argument of size
    	 * within 13 bits. We can safely pick up the size from the command.
    	 */
    	size = _IOC_SIZE(handler->cmd);
    	if (handler->cmd & IOC_IN) {
    		if (copy_from_user(&buf, (const void __user *)arg, size))
    			return -EFAULT;
    	}
    
    	mutex_lock(&client->ioctl_mutex);
    	err = handler->func(client, &buf);
    	mutex_unlock(&client->ioctl_mutex);
    	if (err >= 0) {
    		/* Some commands includes a bug in 'dir' field. */
    		if (handler->cmd == SNDRV_SEQ_IOCTL_SET_QUEUE_CLIENT ||
    		    handler->cmd == SNDRV_SEQ_IOCTL_SET_CLIENT_POOL ||
    		    (handler->cmd & IOC_OUT))
    			if (copy_to_user((void __user *)arg, &buf, size))
    				return -EFAULT;
    	}
    
    	return err;
    }
    
    #ifdef CONFIG_COMPAT
    #include "seq_compat.c"
    #else
    #define snd_seq_ioctl_compat	NULL
    #endif
    
    /* -------------------------------------------------------- */
    
    
    /* exported to kernel modules */
    int snd_seq_create_kernel_client(struct snd_card *card, int client_index,
    				 const char *name_fmt, ...)
    {
    	struct snd_seq_client *client;
    	va_list args;
    
    	if (snd_BUG_ON(in_interrupt()))
    		return -EBUSY;
    
    	if (card && client_index >= SNDRV_SEQ_CLIENTS_PER_CARD)
    		return -EINVAL;
    	if (card == NULL && client_index >= SNDRV_SEQ_GLOBAL_CLIENTS)
    		return -EINVAL;
    
    	if (mutex_lock_interruptible(&register_mutex))
    		return -ERESTARTSYS;
    
    	if (card) {
    		client_index += SNDRV_SEQ_GLOBAL_CLIENTS
    			+ card->number * SNDRV_SEQ_CLIENTS_PER_CARD;
    		if (client_index >= SNDRV_SEQ_DYNAMIC_CLIENTS_BEGIN)
    			client_index = -1;
    	}
    
    	/* empty write queue as default */
    	client = seq_create_client1(client_index, 0);
    	if (client == NULL) {
    		mutex_unlock(&register_mutex);
    		return -EBUSY;	/* failure code */
    	}
    	usage_alloc(&client_usage, 1);
    
    	client->accept_input = 1;
    	client->accept_output = 1;
    	client->data.kernel.card = card;
    		
    	va_start(args, name_fmt);
    	vsnprintf(client->name, sizeof(client->name), name_fmt, args);
    	va_end(args);
    
    	client->type = KERNEL_CLIENT;
    	mutex_unlock(&register_mutex);
    
    	/* make others aware this new client */
    	snd_seq_system_client_ev_client_start(client->number);
    	
    	/* return client number to caller */
    	return client->number;
    }
    EXPORT_SYMBOL(snd_seq_create_kernel_client);
    
    /* exported to kernel modules */
    int snd_seq_delete_kernel_client(int client)
    {
    	struct snd_seq_client *ptr;
    
    	if (snd_BUG_ON(in_interrupt()))
    		return -EBUSY;
    
    	ptr = clientptr(client);
    	if (ptr == NULL)
    		return -EINVAL;
    
    	seq_free_client(ptr);
    	kfree(ptr);
    	return 0;
    }
    EXPORT_SYMBOL(snd_seq_delete_kernel_client);
    
    /* skeleton to enqueue event, called from snd_seq_kernel_client_enqueue
     * and snd_seq_kernel_client_enqueue_blocking
     */
    static int kernel_client_enqueue(int client, struct snd_seq_event *ev,
    				 struct file *file, int blocking,
    				 int atomic, int hop)
    {
    	struct snd_seq_client *cptr;
    	int result;
    
    	if (snd_BUG_ON(!ev))
    		return -EINVAL;
    
    	if (ev->type == SNDRV_SEQ_EVENT_NONE)
    		return 0; /* ignore this */
    	if (ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR)
    		return -EINVAL; /* quoted events can't be enqueued */
    
    	/* fill in client number */
    	ev->source.client = client;
    
    	if (check_event_type_and_length(ev))
    		return -EINVAL;
    
    	cptr = snd_seq_client_use_ptr(client);
    	if (cptr == NULL)
    		return -EINVAL;
    	
    	if (! cptr->accept_output)
    		result = -EPERM;
    	else /* send it */
    		result = snd_seq_client_enqueue_event(cptr, ev, file, blocking, atomic, hop);
    
    	snd_seq_client_unlock(cptr);
    	return result;
    }
    
    /*
     * exported, called by kernel clients to enqueue events (w/o blocking)
     *
     * RETURN VALUE: zero if succeed, negative if error
     */
    int snd_seq_kernel_client_enqueue(int client, struct snd_seq_event * ev,
    				  int atomic, int hop)
    {
    	return kernel_client_enqueue(client, ev, NULL, 0, atomic, hop);
    }
    EXPORT_SYMBOL(snd_seq_kernel_client_enqueue);
    
    /*
     * exported, called by kernel clients to enqueue events (with blocking)
     *
     * RETURN VALUE: zero if succeed, negative if error
     */
    int snd_seq_kernel_client_enqueue_blocking(int client, struct snd_seq_event * ev,
    					   struct file *file,
    					   int atomic, int hop)
    {
    	return kernel_client_enqueue(client, ev, file, 1, atomic, hop);
    }
    EXPORT_SYMBOL(snd_seq_kernel_client_enqueue_blocking);
    
    /* 
     * exported, called by kernel clients to dispatch events directly to other
     * clients, bypassing the queues.  Event time-stamp will be updated.
     *
     * RETURN VALUE: negative = delivery failed,
     *		 zero, or positive: the number of delivered events
     */
    int snd_seq_kernel_client_dispatch(int client, struct snd_seq_event * ev,
    				   int atomic, int hop)
    {
    	struct snd_seq_client *cptr;
    	int result;
    
    	if (snd_BUG_ON(!ev))
    		return -EINVAL;
    
    	/* fill in client number */
    	ev->queue = SNDRV_SEQ_QUEUE_DIRECT;
    	ev->source.client = client;
    
    	if (check_event_type_and_length(ev))
    		return -EINVAL;
    
    	cptr = snd_seq_client_use_ptr(client);
    	if (cptr == NULL)
    		return -EINVAL;
    
    	if (!cptr->accept_output)
    		result = -EPERM;
    	else
    		result = snd_seq_deliver_event(cptr, ev, atomic, hop);
    
    	snd_seq_client_unlock(cptr);
    	return result;
    }
    EXPORT_SYMBOL(snd_seq_kernel_client_dispatch);
    
    /**
     * snd_seq_kernel_client_ctl - operate a command for a client with data in
     *			       kernel space.
     * @clientid:	A numerical ID for a client.
     * @cmd:	An ioctl(2) command for ALSA sequencer operation.
     * @arg:	A pointer to data in kernel space.
     *
     * Against its name, both kernel/application client can be handled by this
     * kernel API. A pointer of 'arg' argument should be in kernel space.
     *
     * Return: 0 at success. Negative error code at failure.
     */
    int snd_seq_kernel_client_ctl(int clientid, unsigned int cmd, void *arg)
    {
    	const struct ioctl_handler *handler;
    	struct snd_seq_client *client;
    
    	client = clientptr(clientid);
    	if (client == NULL)
    		return -ENXIO;
    
    	for (handler = ioctl_handlers; handler->cmd > 0; ++handler) {
    		if (handler->cmd == cmd)
    			return handler->func(client, arg);
    	}
    
    	pr_debug("ALSA: seq unknown ioctl() 0x%x (type='%c', number=0x%02x)\n",
    		 cmd, _IOC_TYPE(cmd), _IOC_NR(cmd));
    	return -ENOTTY;
    }
    EXPORT_SYMBOL(snd_seq_kernel_client_ctl);
    
    /* exported (for OSS emulator) */
    int snd_seq_kernel_client_write_poll(int clientid, struct file *file, poll_table *wait)
    {
    	struct snd_seq_client *client;
    
    	client = clientptr(clientid);
    	if (client == NULL)
    		return -ENXIO;
    
    	if (! snd_seq_write_pool_allocated(client))
    		return 1;
    	if (snd_seq_pool_poll_wait(client->pool, file, wait))
    		return 1;
    	return 0;
    }
    EXPORT_SYMBOL(snd_seq_kernel_client_write_poll);
    
    /*---------------------------------------------------------------------------*/
    
    #ifdef CONFIG_SND_PROC_FS
    /*
     *  /proc interface
     */
    static void snd_seq_info_dump_subscribers(struct snd_info_buffer *buffer,
    					  struct snd_seq_port_subs_info *group,
    					  int is_src, char *msg)
    {
    	struct list_head *p;
    	struct snd_seq_subscribers *s;
    	int count = 0;
    
    	down_read(&group->list_mutex);
    	if (list_empty(&group->list_head)) {
    		up_read(&group->list_mutex);
    		return;
    	}
    	snd_iprintf(buffer, msg);
    	list_for_each(p, &group->list_head) {
    		if (is_src)
    			s = list_entry(p, struct snd_seq_subscribers, src_list);
    		else
    			s = list_entry(p, struct snd_seq_subscribers, dest_list);
    		if (count++)
    			snd_iprintf(buffer, ", ");
    		snd_iprintf(buffer, "%d:%d",
    			    is_src ? s->info.dest.client : s->info.sender.client,
    			    is_src ? s->info.dest.port : s->info.sender.port);
    		if (s->info.flags & SNDRV_SEQ_PORT_SUBS_TIMESTAMP)
    			snd_iprintf(buffer, "[%c:%d]", ((s->info.flags & SNDRV_SEQ_PORT_SUBS_TIME_REAL) ? 'r' : 't'), s->info.queue);
    		if (group->exclusive)
    			snd_iprintf(buffer, "[ex]");
    	}
    	up_read(&group->list_mutex);
    	snd_iprintf(buffer, "\n");
    }
    
    #define FLAG_PERM_RD(perm) ((perm) & SNDRV_SEQ_PORT_CAP_READ ? ((perm) & SNDRV_SEQ_PORT_CAP_SUBS_READ ? 'R' : 'r') : '-')
    #define FLAG_PERM_WR(perm) ((perm) & SNDRV_SEQ_PORT_CAP_WRITE ? ((perm) & SNDRV_SEQ_PORT_CAP_SUBS_WRITE ? 'W' : 'w') : '-')
    #define FLAG_PERM_EX(perm) ((perm) & SNDRV_SEQ_PORT_CAP_NO_EXPORT ? '-' : 'e')
    
    #define FLAG_PERM_DUPLEX(perm) ((perm) & SNDRV_SEQ_PORT_CAP_DUPLEX ? 'X' : '-')
    
    static void snd_seq_info_dump_ports(struct snd_info_buffer *buffer,
    				    struct snd_seq_client *client)
    {
    	struct snd_seq_client_port *p;
    
    	mutex_lock(&client->ports_mutex);
    	list_for_each_entry(p, &client->ports_list_head, list) {
    		snd_iprintf(buffer, "  Port %3d : \"%s\" (%c%c%c%c)\n",
    			    p->addr.port, p->name,
    			    FLAG_PERM_RD(p->capability),
    			    FLAG_PERM_WR(p->capability),
    			    FLAG_PERM_EX(p->capability),
    			    FLAG_PERM_DUPLEX(p->capability));
    		snd_seq_info_dump_subscribers(buffer, &p->c_src, 1, "    Connecting To: ");
    		snd_seq_info_dump_subscribers(buffer, &p->c_dest, 0, "    Connected From: ");
    	}
    	mutex_unlock(&client->ports_mutex);
    }
    
    
    /* exported to seq_info.c */
    void snd_seq_info_clients_read(struct snd_info_entry *entry, 
    			       struct snd_info_buffer *buffer)
    {
    	int c;
    	struct snd_seq_client *client;
    
    	snd_iprintf(buffer, "Client info\n");
    	snd_iprintf(buffer, "  cur  clients : %d\n", client_usage.cur);
    	snd_iprintf(buffer, "  peak clients : %d\n", client_usage.peak);
    	snd_iprintf(buffer, "  max  clients : %d\n", SNDRV_SEQ_MAX_CLIENTS);
    	snd_iprintf(buffer, "\n");
    
    	/* list the client table */
    	for (c = 0; c < SNDRV_SEQ_MAX_CLIENTS; c++) {
    		client = snd_seq_client_use_ptr(c);
    		if (client == NULL)
    			continue;
    		if (client->type == NO_CLIENT) {
    			snd_seq_client_unlock(client);
    			continue;
    		}
    
    		snd_iprintf(buffer, "Client %3d : \"%s\" [%s]\n",
    			    c, client->name,
    			    client->type == USER_CLIENT ? "User" : "Kernel");
    		snd_seq_info_dump_ports(buffer, client);
    		if (snd_seq_write_pool_allocated(client)) {
    			snd_iprintf(buffer, "  Output pool :\n");
    			snd_seq_info_pool(buffer, client->pool, "    ");
    		}
    		if (client->type == USER_CLIENT && client->data.user.fifo &&
    		    client->data.user.fifo->pool) {
    			snd_iprintf(buffer, "  Input pool :\n");
    			snd_seq_info_pool(buffer, client->data.user.fifo->pool, "    ");
    		}
    		snd_seq_client_unlock(client);
    	}
    }
    #endif /* CONFIG_SND_PROC_FS */
    
    /*---------------------------------------------------------------------------*/
    
    
    /*
     *  REGISTRATION PART
     */
    
    static const struct file_operations snd_seq_f_ops =
    {
    	.owner =	THIS_MODULE,
    	.read =		snd_seq_read,
    	.write =	snd_seq_write,
    	.open =		snd_seq_open,
    	.release =	snd_seq_release,
    	.llseek =	no_llseek,
    	.poll =		snd_seq_poll,
    	.unlocked_ioctl =	snd_seq_ioctl,
    	.compat_ioctl =	snd_seq_ioctl_compat,
    };
    
    static struct device seq_dev;
    
    /* 
     * register sequencer device 
     */
    int __init snd_sequencer_device_init(void)
    {
    	int err;
    
    	snd_device_initialize(&seq_dev, NULL);
    	dev_set_name(&seq_dev, "seq");
    
    	if (mutex_lock_interruptible(&register_mutex))
    		return -ERESTARTSYS;
    
    	err = snd_register_device(SNDRV_DEVICE_TYPE_SEQUENCER, NULL, 0,
    				  &snd_seq_f_ops, NULL, &seq_dev);
    	if (err < 0) {
    		mutex_unlock(&register_mutex);
    		put_device(&seq_dev);
    		return err;
    	}
    	
    	mutex_unlock(&register_mutex);
    
    	return 0;
    }
    
    
    
    /* 
     * unregister sequencer device 
     */
    void __exit snd_sequencer_device_done(void)
    {
    	snd_unregister_device(&seq_dev);
    	put_device(&seq_dev);
    }