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      1 /**
      2  * Copyright (c) 2010-2012 Broadcom. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions, and the following disclaimer,
      9  *    without modification.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. The names of the above-listed copyright holders may not be used
     14  *    to endorse or promote products derived from this software without
     15  *    specific prior written permission.
     16  *
     17  * ALTERNATIVELY, this software may be distributed under the terms of the
     18  * GNU General Public License ("GPL") version 2, as published by the Free
     19  * Software Foundation.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
     22  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     23  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     24  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
     25  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     27  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     28  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     29  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     30  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     31  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     32  */
     33 
     34 #include "vchiq_connected.h"
     35 #include "vchiq_core.h"
     36 
     37 #define  MAX_CALLBACKS  10
     38 
     39 static   int                        g_connected;
     40 static   int                        g_num_deferred_callbacks;
     41 static   VCHIQ_CONNECTED_CALLBACK_T g_deferred_callback[MAX_CALLBACKS];
     42 static   int                        g_once_init;
     43 static   struct mutex               g_connected_mutex;
     44 
     45 /****************************************************************************
     46 *
     47 * Function to initialize our lock.
     48 *
     49 ***************************************************************************/
     50 
     51 static void connected_init(void)
     52 {
     53 	if (!g_once_init) {
     54 		lmutex_init(&g_connected_mutex);
     55 		g_once_init = 1;
     56 	}
     57 }
     58 
     59 /****************************************************************************
     60 *
     61 * This function is used to defer initialization until the vchiq stack is
     62 * initialized. If the stack is already initialized, then the callback will
     63 * be made immediately, otherwise it will be deferred until
     64 * vchiq_call_connected_callbacks is called.
     65 *
     66 ***************************************************************************/
     67 
     68 void vchiq_add_connected_callback(VCHIQ_CONNECTED_CALLBACK_T callback)
     69 {
     70 	connected_init();
     71 
     72 	if (lmutex_lock_interruptible(&g_connected_mutex) != 0)
     73 		return;
     74 
     75 	if (g_connected)
     76 		/* We're already connected. Call the callback immediately. */
     77 
     78 		callback();
     79 	else {
     80 		if (g_num_deferred_callbacks >= MAX_CALLBACKS)
     81 			vchiq_log_error(vchiq_core_log_level,
     82 				"There are already %d callbacks registered - "
     83 				"please increase MAX_CALLBACKS",
     84 				g_num_deferred_callbacks);
     85 		else {
     86 			g_deferred_callback[g_num_deferred_callbacks] =
     87 				callback;
     88 			g_num_deferred_callbacks++;
     89 		}
     90 	}
     91 	lmutex_unlock(&g_connected_mutex);
     92 }
     93 
     94 /****************************************************************************
     95 *
     96 * This function is called by the vchiq stack once it has been connected to
     97 * the videocore and clients can start to use the stack.
     98 *
     99 ***************************************************************************/
    100 
    101 void vchiq_call_connected_callbacks(void)
    102 {
    103 	int i;
    104 
    105 	connected_init();
    106 
    107 	if (lmutex_lock_interruptible(&g_connected_mutex) != 0)
    108 		return;
    109 
    110 	for (i = 0; i <  g_num_deferred_callbacks; i++)
    111 		g_deferred_callback[i]();
    112 
    113 	g_num_deferred_callbacks = 0;
    114 	g_connected = 1;
    115 	lmutex_unlock(&g_connected_mutex);
    116 }
    117 EXPORT_SYMBOL(vchiq_add_connected_callback);
    118