1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2 /* Copyright (c) 2010-2012 Broadcom. All rights reserved. */
3 
4 #include "vchiq_connected.h"
5 #include "vchiq_core.h"
6 #include <linux/module.h>
7 #include <linux/mutex.h>
8 
9 #define  MAX_CALLBACKS  10
10 
11 static   int                        g_connected;
12 static   int                        g_num_deferred_callbacks;
13 static   VCHIQ_CONNECTED_CALLBACK_T g_deferred_callback[MAX_CALLBACKS];
14 static   int                        g_once_init;
15 static   struct mutex               g_connected_mutex;
16 
17 /****************************************************************************
18 *
19 * Function to initialize our lock.
20 *
21 ***************************************************************************/
22 
connected_init(void)23 static void connected_init(void)
24 {
25 	if (!g_once_init) {
26 		mutex_init(&g_connected_mutex);
27 		g_once_init = 1;
28 	}
29 }
30 
31 /****************************************************************************
32 *
33 * This function is used to defer initialization until the vchiq stack is
34 * initialized. If the stack is already initialized, then the callback will
35 * be made immediately, otherwise it will be deferred until
36 * vchiq_call_connected_callbacks is called.
37 *
38 ***************************************************************************/
39 
vchiq_add_connected_callback(VCHIQ_CONNECTED_CALLBACK_T callback)40 void vchiq_add_connected_callback(VCHIQ_CONNECTED_CALLBACK_T callback)
41 {
42 	connected_init();
43 
44 	if (mutex_lock_killable(&g_connected_mutex))
45 		return;
46 
47 	if (g_connected)
48 		/* We're already connected. Call the callback immediately. */
49 
50 		callback();
51 	else {
52 		if (g_num_deferred_callbacks >= MAX_CALLBACKS)
53 			vchiq_log_error(vchiq_core_log_level,
54 				"There already %d callback registered - "
55 				"please increase MAX_CALLBACKS",
56 				g_num_deferred_callbacks);
57 		else {
58 			g_deferred_callback[g_num_deferred_callbacks] =
59 				callback;
60 			g_num_deferred_callbacks++;
61 		}
62 	}
63 	mutex_unlock(&g_connected_mutex);
64 }
65 
66 /****************************************************************************
67 *
68 * This function is called by the vchiq stack once it has been connected to
69 * the videocore and clients can start to use the stack.
70 *
71 ***************************************************************************/
72 
vchiq_call_connected_callbacks(void)73 void vchiq_call_connected_callbacks(void)
74 {
75 	int i;
76 
77 	connected_init();
78 
79 	if (mutex_lock_killable(&g_connected_mutex))
80 		return;
81 
82 	for (i = 0; i <  g_num_deferred_callbacks; i++)
83 		g_deferred_callback[i]();
84 
85 	g_num_deferred_callbacks = 0;
86 	g_connected = 1;
87 	mutex_unlock(&g_connected_mutex);
88 }
89 EXPORT_SYMBOL(vchiq_add_connected_callback);
90