LXR linux/drivers/staging/vc04_services/interface/vchiq_arm/vchiq

   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
  42static   int                        g_connected;
  43static   int                        g_num_deferred_callbacks;
  44static   VCHIQ_CONNECTED_CALLBACK_T g_deferred_callback[MAX_CALLBACKS];
  45static   int                        g_once_init;
  46static   struct mutex               g_connected_mutex;
  47
  48/****************************************************************************
  49*
  50* Function to initialize our lock.
  51*
  52***************************************************************************/
  53
  54static 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
  71void 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
 104void 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}
 120EXPORT_SYMBOL(vchiq_add_connected_callback);
 121