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