drivers/staging/vc04_services/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 #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_interruptible(&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_interruptible(&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);