drivers/media/cec/cec-api.c

   1 /*
   2  * cec-api.c - HDMI Consumer Electronics Control framework - API
   3  *
   4  * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
   5  *
   6  * This program is free software; you may redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  11  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  12  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  13  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  14  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  15  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  16  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  17  * SOFTWARE.
  18  */
  19
  20 #include <linux/errno.h>
  21 #include <linux/init.h>
  22 #include <linux/module.h>
  23 #include <linux/kernel.h>
  24 #include <linux/kmod.h>
  25 #include <linux/ktime.h>
  26 #include <linux/slab.h>
  27 #include <linux/mm.h>
  28 #include <linux/string.h>
  29 #include <linux/types.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/version.h>
  32
  33 #include "cec-priv.h"
  34
  35 static inline struct cec_devnode *cec_devnode_data(struct file *filp)
  36 {
  37         struct cec_fh *fh = filp->private_data;
  38
  39         return &fh->adap->devnode;
  40 }
  41
  42 /* CEC file operations */
  43
  44 static unsigned int cec_poll(struct file *filp,
  45                              struct poll_table_struct *poll)
  46 {
  47         struct cec_devnode *devnode = cec_devnode_data(filp);
  48         struct cec_fh *fh = filp->private_data;
  49         struct cec_adapter *adap = fh->adap;
  50         unsigned int res = 0;
  51
  52         if (!devnode->registered)
  53                 return POLLERR | POLLHUP;
  54         mutex_lock(&adap->lock);
  55         if (adap->is_configured &&
  56             adap->transmit_queue_sz < CEC_MAX_MSG_TX_QUEUE_SZ)
  57                 res |= POLLOUT | POLLWRNORM;
  58         if (fh->queued_msgs)
  59                 res |= POLLIN | POLLRDNORM;
  60         if (fh->pending_events)
  61                 res |= POLLPRI;
  62         poll_wait(filp, &fh->wait, poll);
  63         mutex_unlock(&adap->lock);
  64         return res;
  65 }
  66
  67 static bool cec_is_busy(const struct cec_adapter *adap,
  68                         const struct cec_fh *fh)
  69 {
  70         bool valid_initiator = adap->cec_initiator && adap->cec_initiator == fh;
  71         bool valid_follower = adap->cec_follower && adap->cec_follower == fh;
  72
  73         /*
  74          * Exclusive initiators and followers can always access the CEC adapter
  75          */
  76         if (valid_initiator || valid_follower)
  77                 return false;
  78         /*
  79          * All others can only access the CEC adapter if there is no
  80          * exclusive initiator and they are in INITIATOR mode.
  81          */
  82         return adap->cec_initiator ||
  83                fh->mode_initiator == CEC_MODE_NO_INITIATOR;
  84 }
  85
  86 static long cec_adap_g_caps(struct cec_adapter *adap,
  87                             struct cec_caps __user *parg)
  88 {
  89         struct cec_caps caps = {};
  90
  91         strlcpy(caps.driver, adap->devnode.dev.parent->driver->name,
  92                 sizeof(caps.driver));
  93         strlcpy(caps.name, adap->name, sizeof(caps.name));
  94         caps.available_log_addrs = adap->available_log_addrs;
  95         caps.capabilities = adap->capabilities;
  96         caps.version = LINUX_VERSION_CODE;
  97         if (copy_to_user(parg, &caps, sizeof(caps)))
  98                 return -EFAULT;
  99         return 0;
 100 }
 101
 102 static long cec_adap_g_phys_addr(struct cec_adapter *adap,
 103                                  __u16 __user *parg)
 104 {
 105         u16 phys_addr;
 106
 107         mutex_lock(&adap->lock);
 108         phys_addr = adap->phys_addr;
 109         mutex_unlock(&adap->lock);
 110         if (copy_to_user(parg, &phys_addr, sizeof(phys_addr)))
 111                 return -EFAULT;
 112         return 0;
 113 }
 114
 115 static long cec_adap_s_phys_addr(struct cec_adapter *adap, struct cec_fh *fh,
 116                                  bool block, __u16 __user *parg)
 117 {
 118         u16 phys_addr;
 119         long err;
 120
 121         if (!(adap->capabilities & CEC_CAP_PHYS_ADDR))
 122                 return -ENOTTY;
 123         if (copy_from_user(&phys_addr, parg, sizeof(phys_addr)))
 124                 return -EFAULT;
 125
 126         err = cec_phys_addr_validate(phys_addr, NULL, NULL);
 127         if (err)
 128                 return err;
 129         mutex_lock(&adap->lock);
 130         if (cec_is_busy(adap, fh))
 131                 err = -EBUSY;
 132         else
 133                 __cec_s_phys_addr(adap, phys_addr, block);
 134         mutex_unlock(&adap->lock);
 135         return err;
 136 }
 137
 138 static long cec_adap_g_log_addrs(struct cec_adapter *adap,
 139                                  struct cec_log_addrs __user *parg)
 140 {
 141         struct cec_log_addrs log_addrs;
 142
 143         mutex_lock(&adap->lock);
 144         log_addrs = adap->log_addrs;
 145         if (!adap->is_configured)
 146                 memset(log_addrs.log_addr, CEC_LOG_ADDR_INVALID,
 147                        sizeof(log_addrs.log_addr));
 148         mutex_unlock(&adap->lock);
 149
 150         if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
 151                 return -EFAULT;
 152         return 0;
 153 }
 154
 155 static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh,
 156                                  bool block, struct cec_log_addrs __user *parg)
 157 {
 158         struct cec_log_addrs log_addrs;
 159         long err = -EBUSY;
 160
 161         if (!(adap->capabilities & CEC_CAP_LOG_ADDRS))
 162                 return -ENOTTY;
 163         if (copy_from_user(&log_addrs, parg, sizeof(log_addrs)))
 164                 return -EFAULT;
 165         log_addrs.flags &= CEC_LOG_ADDRS_FL_ALLOW_UNREG_FALLBACK |
 166                            CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU |
 167                            CEC_LOG_ADDRS_FL_CDC_ONLY;
 168         mutex_lock(&adap->lock);
 169         if (!adap->is_configuring &&
 170             (!log_addrs.num_log_addrs || !adap->is_configured) &&
 171             !cec_is_busy(adap, fh)) {
 172                 err = __cec_s_log_addrs(adap, &log_addrs, block);
 173                 if (!err)
 174                         log_addrs = adap->log_addrs;
 175         }
 176         mutex_unlock(&adap->lock);
 177         if (err)
 178                 return err;
 179         if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
 180                 return -EFAULT;
 181         return 0;
 182 }
 183
 184 static long cec_transmit(struct cec_adapter *adap, struct cec_fh *fh,
 185                          bool block, struct cec_msg __user *parg)
 186 {
 187         struct cec_msg msg = {};
 188         long err = 0;
 189
 190         if (!(adap->capabilities & CEC_CAP_TRANSMIT))
 191                 return -ENOTTY;
 192         if (copy_from_user(&msg, parg, sizeof(msg)))
 193                 return -EFAULT;
 194
 195         /* A CDC-Only device can only send CDC messages */
 196         if ((adap->log_addrs.flags & CEC_LOG_ADDRS_FL_CDC_ONLY) &&
 197             (msg.len == 1 || msg.msg[1] != CEC_MSG_CDC_MESSAGE))
 198                 return -EINVAL;
 199
 200         mutex_lock(&adap->lock);
 201         if (adap->log_addrs.num_log_addrs == 0)
 202                 err = -EPERM;
 203         else if (adap->is_configuring)
 204                 err = -ENONET;
 205         else if (!adap->is_configured && msg.msg[0] != 0xf0)
 206                 err = -ENONET;
 207         else if (cec_is_busy(adap, fh))
 208                 err = -EBUSY;
 209         else
 210                 err = cec_transmit_msg_fh(adap, &msg, fh, block);
 211         mutex_unlock(&adap->lock);
 212         if (err)
 213                 return err;
 214         if (copy_to_user(parg, &msg, sizeof(msg)))
 215                 return -EFAULT;
 216         return 0;
 217 }
 218
 219 /* Called by CEC_RECEIVE: wait for a message to arrive */
 220 static int cec_receive_msg(struct cec_fh *fh, struct cec_msg *msg, bool block)
 221 {
 222         u32 timeout = msg->timeout;
 223         int res;
 224
 225         do {
 226                 mutex_lock(&fh->lock);
 227                 /* Are there received messages queued up? */
 228                 if (fh->queued_msgs) {
 229                         /* Yes, return the first one */
 230                         struct cec_msg_entry *entry =
 231                                 list_first_entry(&fh->msgs,
 232                                                  struct cec_msg_entry, list);
 233
 234                         list_del(&entry->list);
 235                         *msg = entry->msg;
 236                         kfree(entry);
 237                         fh->queued_msgs--;
 238                         mutex_unlock(&fh->lock);
 239                         /* restore original timeout value */
 240                         msg->timeout = timeout;
 241                         return 0;
 242                 }
 243
 244                 /* No, return EAGAIN in non-blocking mode or wait */
 245                 mutex_unlock(&fh->lock);
 246
 247                 /* Return when in non-blocking mode */
 248                 if (!block)
 249                         return -EAGAIN;
 250
 251                 if (msg->timeout) {
 252                         /* The user specified a timeout */
 253                         res = wait_event_interruptible_timeout(fh->wait,
 254                                                                fh->queued_msgs,
 255                                 msecs_to_jiffies(msg->timeout));
 256                         if (res == 0)
 257                                 res = -ETIMEDOUT;
 258                         else if (res > 0)
 259                                 res = 0;
 260                 } else {
 261                         /* Wait indefinitely */
 262                         res = wait_event_interruptible(fh->wait,
 263                                                        fh->queued_msgs);
 264                 }
 265                 /* Exit on error, otherwise loop to get the new message */
 266         } while (!res);
 267         return res;
 268 }
 269
 270 static long cec_receive(struct cec_adapter *adap, struct cec_fh *fh,
 271                         bool block, struct cec_msg __user *parg)
 272 {
 273         struct cec_msg msg = {};
 274         long err = 0;
 275
 276         if (copy_from_user(&msg, parg, sizeof(msg)))
 277                 return -EFAULT;
 278         mutex_lock(&adap->lock);
 279         if (!adap->is_configured && fh->mode_follower < CEC_MODE_MONITOR)
 280                 err = -ENONET;
 281         mutex_unlock(&adap->lock);
 282         if (err)
 283                 return err;
 284
 285         err = cec_receive_msg(fh, &msg, block);
 286         if (err)
 287                 return err;
 288         msg.flags = 0;
 289         if (copy_to_user(parg, &msg, sizeof(msg)))
 290                 return -EFAULT;
 291         return 0;
 292 }
 293
 294 static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
 295                         bool block, struct cec_event __user *parg)
 296 {
 297         struct cec_event *ev = NULL;
 298         u64 ts = ~0ULL;
 299         unsigned int i;
 300         long err = 0;
 301
 302         mutex_lock(&fh->lock);
 303         while (!fh->pending_events && block) {
 304                 mutex_unlock(&fh->lock);
 305                 err = wait_event_interruptible(fh->wait, fh->pending_events);
 306                 if (err)
 307                         return err;
 308                 mutex_lock(&fh->lock);
 309         }
 310
 311         /* Find the oldest event */
 312         for (i = 0; i < CEC_NUM_EVENTS; i++) {
 313                 if (fh->pending_events & (1 << (i + 1)) &&
 314                     fh->events[i].ts <= ts) {
 315                         ev = &fh->events[i];
 316                         ts = ev->ts;
 317                 }
 318         }
 319         if (!ev) {
 320                 err = -EAGAIN;
 321                 goto unlock;
 322         }
 323
 324         if (copy_to_user(parg, ev, sizeof(*ev))) {
 325                 err = -EFAULT;
 326                 goto unlock;
 327         }
 328
 329         fh->pending_events &= ~(1 << ev->event);
 330
 331 unlock:
 332         mutex_unlock(&fh->lock);
 333         return err;
 334 }
 335
 336 static long cec_g_mode(struct cec_adapter *adap, struct cec_fh *fh,
 337                        u32 __user *parg)
 338 {
 339         u32 mode = fh->mode_initiator | fh->mode_follower;
 340
 341         if (copy_to_user(parg, &mode, sizeof(mode)))
 342                 return -EFAULT;
 343         return 0;
 344 }
 345
 346 static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
 347                        u32 __user *parg)
 348 {
 349         u32 mode;
 350         u8 mode_initiator;
 351         u8 mode_follower;
 352         long err = 0;
 353
 354         if (copy_from_user(&mode, parg, sizeof(mode)))
 355                 return -EFAULT;
 356         if (mode & ~(CEC_MODE_INITIATOR_MSK | CEC_MODE_FOLLOWER_MSK))
 357                 return -EINVAL;
 358
 359         mode_initiator = mode & CEC_MODE_INITIATOR_MSK;
 360         mode_follower = mode & CEC_MODE_FOLLOWER_MSK;
 361
 362         if (mode_initiator > CEC_MODE_EXCL_INITIATOR ||
 363             mode_follower > CEC_MODE_MONITOR_ALL)
 364                 return -EINVAL;
 365
 366         if (mode_follower == CEC_MODE_MONITOR_ALL &&
 367             !(adap->capabilities & CEC_CAP_MONITOR_ALL))
 368                 return -EINVAL;
 369
 370         /* Follower modes should always be able to send CEC messages */
 371         if ((mode_initiator == CEC_MODE_NO_INITIATOR ||
 372              !(adap->capabilities & CEC_CAP_TRANSMIT)) &&
 373             mode_follower >= CEC_MODE_FOLLOWER &&
 374             mode_follower <= CEC_MODE_EXCL_FOLLOWER_PASSTHRU)
 375                 return -EINVAL;
 376
 377         /* Monitor modes require CEC_MODE_NO_INITIATOR */
 378         if (mode_initiator && mode_follower >= CEC_MODE_MONITOR)
 379                 return -EINVAL;
 380
 381         /* Monitor modes require CAP_NET_ADMIN */
 382         if (mode_follower >= CEC_MODE_MONITOR && !capable(CAP_NET_ADMIN))
 383                 return -EPERM;
 384
 385         mutex_lock(&adap->lock);
 386         /*
 387          * You can't become exclusive follower if someone else already
 388          * has that job.
 389          */
 390         if ((mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 391              mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) &&
 392             adap->cec_follower && adap->cec_follower != fh)
 393                 err = -EBUSY;
 394         /*
 395          * You can't become exclusive initiator if someone else already
 396          * has that job.
 397          */
 398         if (mode_initiator == CEC_MODE_EXCL_INITIATOR &&
 399             adap->cec_initiator && adap->cec_initiator != fh)
 400                 err = -EBUSY;
 401
 402         if (!err) {
 403                 bool old_mon_all = fh->mode_follower == CEC_MODE_MONITOR_ALL;
 404                 bool new_mon_all = mode_follower == CEC_MODE_MONITOR_ALL;
 405
 406                 if (old_mon_all != new_mon_all) {
 407                         if (new_mon_all)
 408                                 err = cec_monitor_all_cnt_inc(adap);
 409                         else
 410                                 cec_monitor_all_cnt_dec(adap);
 411                 }
 412         }
 413
 414         if (err) {
 415                 mutex_unlock(&adap->lock);
 416                 return err;
 417         }
 418
 419         if (fh->mode_follower == CEC_MODE_FOLLOWER)
 420                 adap->follower_cnt--;
 421         if (mode_follower == CEC_MODE_FOLLOWER)
 422                 adap->follower_cnt++;
 423         if (mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 424             mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
 425                 adap->passthrough =
 426                         mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU;
 427                 adap->cec_follower = fh;
 428         } else if (adap->cec_follower == fh) {
 429                 adap->passthrough = false;
 430                 adap->cec_follower = NULL;
 431         }
 432         if (mode_initiator == CEC_MODE_EXCL_INITIATOR)
 433                 adap->cec_initiator = fh;
 434         else if (adap->cec_initiator == fh)
 435                 adap->cec_initiator = NULL;
 436         fh->mode_initiator = mode_initiator;
 437         fh->mode_follower = mode_follower;
 438         mutex_unlock(&adap->lock);
 439         return 0;
 440 }
 441
 442 static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 443 {
 444         struct cec_devnode *devnode = cec_devnode_data(filp);
 445         struct cec_fh *fh = filp->private_data;
 446         struct cec_adapter *adap = fh->adap;
 447         bool block = !(filp->f_flags & O_NONBLOCK);
 448         void __user *parg = (void __user *)arg;
 449
 450         if (!devnode->registered)
 451                 return -ENODEV;
 452
 453         switch (cmd) {
 454         case CEC_ADAP_G_CAPS:
 455                 return cec_adap_g_caps(adap, parg);
 456
 457         case CEC_ADAP_G_PHYS_ADDR:
 458                 return cec_adap_g_phys_addr(adap, parg);
 459
 460         case CEC_ADAP_S_PHYS_ADDR:
 461                 return cec_adap_s_phys_addr(adap, fh, block, parg);
 462
 463         case CEC_ADAP_G_LOG_ADDRS:
 464                 return cec_adap_g_log_addrs(adap, parg);
 465
 466         case CEC_ADAP_S_LOG_ADDRS:
 467                 return cec_adap_s_log_addrs(adap, fh, block, parg);
 468
 469         case CEC_TRANSMIT:
 470                 return cec_transmit(adap, fh, block, parg);
 471
 472         case CEC_RECEIVE:
 473                 return cec_receive(adap, fh, block, parg);
 474
 475         case CEC_DQEVENT:
 476                 return cec_dqevent(adap, fh, block, parg);
 477
 478         case CEC_G_MODE:
 479                 return cec_g_mode(adap, fh, parg);
 480
 481         case CEC_S_MODE:
 482                 return cec_s_mode(adap, fh, parg);
 483
 484         default:
 485                 return -ENOTTY;
 486         }
 487 }
 488
 489 static int cec_open(struct inode *inode, struct file *filp)
 490 {
 491         struct cec_devnode *devnode =
 492                 container_of(inode->i_cdev, struct cec_devnode, cdev);
 493         struct cec_adapter *adap = to_cec_adapter(devnode);
 494         struct cec_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
 495         /*
 496          * Initial events that are automatically sent when the cec device is
 497          * opened.
 498          */
 499         struct cec_event ev_state = {
 500                 .event = CEC_EVENT_STATE_CHANGE,
 501                 .flags = CEC_EVENT_FL_INITIAL_STATE,
 502         };
 503         int err;
 504
 505         if (!fh)
 506                 return -ENOMEM;
 507
 508         INIT_LIST_HEAD(&fh->msgs);
 509         INIT_LIST_HEAD(&fh->xfer_list);
 510         mutex_init(&fh->lock);
 511         init_waitqueue_head(&fh->wait);
 512
 513         fh->mode_initiator = CEC_MODE_INITIATOR;
 514         fh->adap = adap;
 515
 516         err = cec_get_device(devnode);
 517         if (err) {
 518                 kfree(fh);
 519                 return err;
 520         }
 521
 522         mutex_lock(&devnode->lock);
 523         if (list_empty(&devnode->fhs) &&
 524             adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
 525                 err = adap->ops->adap_enable(adap, true);
 526                 if (err) {
 527                         mutex_unlock(&devnode->lock);
 528                         kfree(fh);
 529                         return err;
 530                 }
 531         }
 532         filp->private_data = fh;
 533
 534         /* Queue up initial state events */
 535         ev_state.state_change.phys_addr = adap->phys_addr;
 536         ev_state.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
 537         cec_queue_event_fh(fh, &ev_state, 0);
 538
 539         list_add(&fh->list, &devnode->fhs);
 540         mutex_unlock(&devnode->lock);
 541
 542         return 0;
 543 }
 544
 545 /* Override for the release function */
 546 static int cec_release(struct inode *inode, struct file *filp)
 547 {
 548         struct cec_devnode *devnode = cec_devnode_data(filp);
 549         struct cec_adapter *adap = to_cec_adapter(devnode);
 550         struct cec_fh *fh = filp->private_data;
 551
 552         mutex_lock(&adap->lock);
 553         if (adap->cec_initiator == fh)
 554                 adap->cec_initiator = NULL;
 555         if (adap->cec_follower == fh) {
 556                 adap->cec_follower = NULL;
 557                 adap->passthrough = false;
 558         }
 559         if (fh->mode_follower == CEC_MODE_FOLLOWER)
 560                 adap->follower_cnt--;
 561         if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
 562                 cec_monitor_all_cnt_dec(adap);
 563         mutex_unlock(&adap->lock);
 564
 565         mutex_lock(&devnode->lock);
 566         list_del(&fh->list);
 567         if (list_empty(&devnode->fhs) &&
 568             adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
 569                 WARN_ON(adap->ops->adap_enable(adap, false));
 570         }
 571         mutex_unlock(&devnode->lock);
 572
 573         /* Unhook pending transmits from this filehandle. */
 574         mutex_lock(&adap->lock);
 575         while (!list_empty(&fh->xfer_list)) {
 576                 struct cec_data *data =
 577                         list_first_entry(&fh->xfer_list, struct cec_data, xfer_list);
 578
 579                 data->blocking = false;
 580                 data->fh = NULL;
 581                 list_del(&data->xfer_list);
 582         }
 583         mutex_unlock(&adap->lock);
 584         while (!list_empty(&fh->msgs)) {
 585                 struct cec_msg_entry *entry =
 586                         list_first_entry(&fh->msgs, struct cec_msg_entry, list);
 587
 588                 list_del(&entry->list);
 589                 kfree(entry);
 590         }
 591         kfree(fh);
 592
 593         cec_put_device(devnode);
 594         filp->private_data = NULL;
 595         return 0;
 596 }
 597
 598 const struct file_operations cec_devnode_fops = {
 599         .owner = THIS_MODULE,
 600         .open = cec_open,
 601         .unlocked_ioctl = cec_ioctl,
 602         .release = cec_release,
 603         .poll = cec_poll,
 604         .llseek = no_llseek,
 605 };