1/* 2 * drivers/media/video/v4l2-int-device.c 3 * 4 * V4L2 internal ioctl interface. 5 * 6 * Copyright (C) 2007 Nokia Corporation. 7 * 8 * Contact: Sakari Ailus <sakari.ailus@nokia.com> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * version 2 as published by the Free Software Foundation. 13 * 14 * This program is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 22 * 02110-1301 USA 23 */ 24 25#include <linux/kernel.h> 26#include <linux/list.h> 27#include <linux/sort.h> 28#include <linux/string.h> 29#include <linux/module.h> 30 31#include "v4l2-int-device.h" 32 33static DEFINE_MUTEX(mutex); 34static LIST_HEAD(int_list); 35 36void v4l2_int_device_try_attach_all(void) 37{ 38 struct v4l2_int_device *m, *s; 39 40 list_for_each_entry(m, &int_list, head) { 41 if (m->type != v4l2_int_type_master) 42 continue; 43 44 list_for_each_entry(s, &int_list, head) { 45 if (s->type != v4l2_int_type_slave) 46 continue; 47 48 /* Slave is connected? */ 49 if (s->u.slave->master) 50 continue; 51 52 /* Slave wants to attach to master? */ 53 if (s->u.slave->attach_to[0] != 0 54 && strncmp(m->name, s->u.slave->attach_to, 55 V4L2NAMESIZE)) 56 continue; 57 58 if (!try_module_get(m->module)) 59 continue; 60 61 s->u.slave->master = m; 62 if (m->u.master->attach(s)) { 63 s->u.slave->master = NULL; 64 module_put(m->module); 65 continue; 66 } 67 } 68 } 69} 70EXPORT_SYMBOL_GPL(v4l2_int_device_try_attach_all); 71 72static int ioctl_sort_cmp(const void *a, const void *b) 73{ 74 const struct v4l2_int_ioctl_desc *d1 = a, *d2 = b; 75 76 if (d1->num > d2->num) 77 return 1; 78 79 if (d1->num < d2->num) 80 return -1; 81 82 return 0; 83} 84 85int v4l2_int_device_register(struct v4l2_int_device *d) 86{ 87 if (d->type == v4l2_int_type_slave) 88 sort(d->u.slave->ioctls, d->u.slave->num_ioctls, 89 sizeof(struct v4l2_int_ioctl_desc), 90 &ioctl_sort_cmp, NULL); 91 mutex_lock(&mutex); 92 list_add(&d->head, &int_list); 93 v4l2_int_device_try_attach_all(); 94 mutex_unlock(&mutex); 95 96 return 0; 97} 98EXPORT_SYMBOL_GPL(v4l2_int_device_register); 99 100void v4l2_int_device_unregister(struct v4l2_int_device *d) 101{ 102 mutex_lock(&mutex); 103 list_del(&d->head); 104 if (d->type == v4l2_int_type_slave 105 && d->u.slave->master != NULL) { 106 d->u.slave->master->u.master->detach(d); 107 module_put(d->u.slave->master->module); 108 d->u.slave->master = NULL; 109 } 110 mutex_unlock(&mutex); 111} 112EXPORT_SYMBOL_GPL(v4l2_int_device_unregister); 113 114/* Adapted from search_extable in extable.c. */ 115static v4l2_int_ioctl_func *find_ioctl(struct v4l2_int_slave *slave, int cmd, 116 v4l2_int_ioctl_func *no_such_ioctl) 117{ 118 const struct v4l2_int_ioctl_desc *first = slave->ioctls; 119 const struct v4l2_int_ioctl_desc *last = 120 first + slave->num_ioctls - 1; 121 122 while (first <= last) { 123 const struct v4l2_int_ioctl_desc *mid; 124 125 mid = (last - first) / 2 + first; 126 127 if (mid->num < cmd) 128 first = mid + 1; 129 else if (mid->num > cmd) 130 last = mid - 1; 131 else 132 return mid->func; 133 } 134 135 return no_such_ioctl; 136} 137 138static int no_such_ioctl_0(struct v4l2_int_device *d) 139{ 140 return -ENOIOCTLCMD; 141} 142 143int v4l2_int_ioctl_0(struct v4l2_int_device *d, int cmd) 144{ 145 return ((v4l2_int_ioctl_func_0 *) 146 find_ioctl(d->u.slave, cmd, 147 (v4l2_int_ioctl_func *)no_such_ioctl_0))(d); 148} 149EXPORT_SYMBOL_GPL(v4l2_int_ioctl_0); 150 151static int no_such_ioctl_1(struct v4l2_int_device *d, void *arg) 152{ 153 return -ENOIOCTLCMD; 154} 155 156int v4l2_int_ioctl_1(struct v4l2_int_device *d, int cmd, void *arg) 157{ 158 return ((v4l2_int_ioctl_func_1 *) 159 find_ioctl(d->u.slave, cmd, 160 (v4l2_int_ioctl_func *)no_such_ioctl_1))(d, arg); 161} 162EXPORT_SYMBOL_GPL(v4l2_int_ioctl_1); 163 164MODULE_LICENSE("GPL"); 165