| 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 void (*g_deferred_callback[MAX_CALLBACKS])(void); |
| 14 | static int g_once_init; |
| 15 | static DEFINE_MUTEX(g_connected_mutex); |
| 16 | |
| 17 | /* Function to initialize our lock */ |
| 18 | static void connected_init(void) |
| 19 | { |
| 20 | if (!g_once_init) |
| 21 | g_once_init = 1; |
| 22 | } |
| 23 | |
| 24 | /* |
| 25 | * This function is used to defer initialization until the vchiq stack is |
| 26 | * initialized. If the stack is already initialized, then the callback will |
| 27 | * be made immediately, otherwise it will be deferred until |
| 28 | * vchiq_call_connected_callbacks is called. |
| 29 | */ |
| 30 | void vchiq_add_connected_callback(struct vchiq_device *device, void (*callback)(void)) |
| 31 | { |
| 32 | connected_init(); |
| 33 | |
| 34 | if (mutex_lock_killable(&g_connected_mutex)) |
| 35 | return; |
| 36 | |
| 37 | if (g_connected) { |
| 38 | /* We're already connected. Call the callback immediately. */ |
| 39 | callback(); |
| 40 | } else { |
| 41 | if (g_num_deferred_callbacks >= MAX_CALLBACKS) { |
| 42 | dev_err(&device->dev, |
| 43 | "core: There already %d callback registered - please increase MAX_CALLBACKS\n", |
| 44 | g_num_deferred_callbacks); |
| 45 | } else { |
| 46 | g_deferred_callback[g_num_deferred_callbacks] = |
| 47 | callback; |
| 48 | g_num_deferred_callbacks++; |
| 49 | } |
| 50 | } |
| 51 | mutex_unlock(lock: &g_connected_mutex); |
| 52 | } |
| 53 | EXPORT_SYMBOL(vchiq_add_connected_callback); |
| 54 | |
| 55 | /* |
| 56 | * This function is called by the vchiq stack once it has been connected to |
| 57 | * the videocore and clients can start to use the stack. |
| 58 | */ |
| 59 | void vchiq_call_connected_callbacks(void) |
| 60 | { |
| 61 | int i; |
| 62 | |
| 63 | connected_init(); |
| 64 | |
| 65 | if (mutex_lock_killable(&g_connected_mutex)) |
| 66 | return; |
| 67 | |
| 68 | for (i = 0; i < g_num_deferred_callbacks; i++) |
| 69 | g_deferred_callback[i](); |
| 70 | |
| 71 | g_num_deferred_callbacks = 0; |
| 72 | g_connected = 1; |
| 73 | mutex_unlock(lock: &g_connected_mutex); |
| 74 | } |
| 75 |