sys/contrib/vchiq/interface/vchiq_arm/vchiq_connected.c

   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);