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 #include "vchiq_killable.h"
37 #include <linux/module.h>
38 #include <linux/mutex.h>
39 
40 #define  MAX_CALLBACKS  10
41 
42 static   int                        g_connected;
43 static   int                        g_num_deferred_callbacks;
44 static   VCHIQ_CONNECTED_CALLBACK_T g_deferred_callback[MAX_CALLBACKS];
45 static   int                        g_once_init;
46 static   struct mutex               g_connected_mutex;
47 
48 /****************************************************************************
49 *
50 * Function to initialize our lock.
51 *
52 ***************************************************************************/
53 
54 static void connected_init(void)
55 {
56 	if (!g_once_init) {
57 		mutex_init(&g_connected_mutex);
58 		g_once_init = 1;
59 	}
60 }
61 
62 /****************************************************************************
63 *
64 * This function is used to defer initialization until the vchiq stack is
65 * initialized. If the stack is already initialized, then the callback will
66 * be made immediately, otherwise it will be deferred until
67 * vchiq_call_connected_callbacks is called.
68 *
69 ***************************************************************************/
70 
71 void vchiq_add_connected_callback(VCHIQ_CONNECTED_CALLBACK_T callback)
72 {
73 	connected_init();
74 
75 	if (mutex_lock_killable(&g_connected_mutex) != 0)
76 		return;
77 
78 	if (g_connected)
79 		/* We're already connected. Call the callback immediately. */
80 
81 		callback();
82 	else {
83 		if (g_num_deferred_callbacks >= MAX_CALLBACKS)
84 			vchiq_log_error(vchiq_core_log_level,
85 				"There already %d callback registered - "
86 				"please increase MAX_CALLBACKS",
87 				g_num_deferred_callbacks);
88 		else {
89 			g_deferred_callback[g_num_deferred_callbacks] =
90 				callback;
91 			g_num_deferred_callbacks++;
92 		}
93 	}
94 	mutex_unlock(&g_connected_mutex);
95 }
96 
97 /****************************************************************************
98 *
99 * This function is called by the vchiq stack once it has been connected to
100 * the videocore and clients can start to use the stack.
101 *
102 ***************************************************************************/
103 
104 void vchiq_call_connected_callbacks(void)
105 {
106 	int i;
107 
108 	connected_init();
109 
110 	if (mutex_lock_killable(&g_connected_mutex) != 0)
111 		return;
112 
113 	for (i = 0; i <  g_num_deferred_callbacks; i++)
114 		g_deferred_callback[i]();
115 
116 	g_num_deferred_callbacks = 0;
117 	g_connected = 1;
118 	mutex_unlock(&g_connected_mutex);
119 }
120 EXPORT_SYMBOL(vchiq_add_connected_callback);
121