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->is_configured)
 202                 err = -ENONET;
 203         else if (cec_is_busy(adap, fh))
 204                 err = -EBUSY;
 205         else
 206                 err = cec_transmit_msg_fh(adap, &msg, fh, block);
 207         mutex_unlock(&adap->lock);
 208         if (err)
 209                 return err;
 210         if (copy_to_user(parg, &msg, sizeof(msg)))
 211                 return -EFAULT;
 212         return 0;
 213 }
 214
 215 /* Called by CEC_RECEIVE: wait for a message to arrive */
 216 static int cec_receive_msg(struct cec_fh *fh, struct cec_msg *msg, bool block)
 217 {
 218         u32 timeout = msg->timeout;
 219         int res;
 220
 221         do {
 222                 mutex_lock(&fh->lock);
 223                 /* Are there received messages queued up? */
 224                 if (fh->queued_msgs) {
 225                         /* Yes, return the first one */
 226                         struct cec_msg_entry *entry =
 227                                 list_first_entry(&fh->msgs,
 228                                                  struct cec_msg_entry, list);
 229
 230                         list_del(&entry->list);
 231                         *msg = entry->msg;
 232                         kfree(entry);
 233                         fh->queued_msgs--;
 234                         mutex_unlock(&fh->lock);
 235                         /* restore original timeout value */
 236                         msg->timeout = timeout;
 237                         return 0;
 238                 }
 239
 240                 /* No, return EAGAIN in non-blocking mode or wait */
 241                 mutex_unlock(&fh->lock);
 242
 243                 /* Return when in non-blocking mode */
 244                 if (!block)
 245                         return -EAGAIN;
 246
 247                 if (msg->timeout) {
 248                         /* The user specified a timeout */
 249                         res = wait_event_interruptible_timeout(fh->wait,
 250                                                                fh->queued_msgs,
 251                                 msecs_to_jiffies(msg->timeout));
 252                         if (res == 0)
 253                                 res = -ETIMEDOUT;
 254                         else if (res > 0)
 255                                 res = 0;
 256                 } else {
 257                         /* Wait indefinitely */
 258                         res = wait_event_interruptible(fh->wait,
 259                                                        fh->queued_msgs);
 260                 }
 261                 /* Exit on error, otherwise loop to get the new message */
 262         } while (!res);
 263         return res;
 264 }
 265
 266 static long cec_receive(struct cec_adapter *adap, struct cec_fh *fh,
 267                         bool block, struct cec_msg __user *parg)
 268 {
 269         struct cec_msg msg = {};
 270         long err = 0;
 271
 272         if (copy_from_user(&msg, parg, sizeof(msg)))
 273                 return -EFAULT;
 274         mutex_lock(&adap->lock);
 275         if (!adap->is_configured && fh->mode_follower < CEC_MODE_MONITOR)
 276                 err = -ENONET;
 277         mutex_unlock(&adap->lock);
 278         if (err)
 279                 return err;
 280
 281         err = cec_receive_msg(fh, &msg, block);
 282         if (err)
 283                 return err;
 284         msg.flags = 0;
 285         if (copy_to_user(parg, &msg, sizeof(msg)))
 286                 return -EFAULT;
 287         return 0;
 288 }
 289
 290 static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
 291                         bool block, struct cec_event __user *parg)
 292 {
 293         struct cec_event *ev = NULL;
 294         u64 ts = ~0ULL;
 295         unsigned int i;
 296         long err = 0;
 297
 298         mutex_lock(&fh->lock);
 299         while (!fh->pending_events && block) {
 300                 mutex_unlock(&fh->lock);
 301                 err = wait_event_interruptible(fh->wait, fh->pending_events);
 302                 if (err)
 303                         return err;
 304                 mutex_lock(&fh->lock);
 305         }
 306
 307         /* Find the oldest event */
 308         for (i = 0; i < CEC_NUM_EVENTS; i++) {
 309                 if (fh->pending_events & (1 << (i + 1)) &&
 310                     fh->events[i].ts <= ts) {
 311                         ev = &fh->events[i];
 312                         ts = ev->ts;
 313                 }
 314         }
 315         if (!ev) {
 316                 err = -EAGAIN;
 317                 goto unlock;
 318         }
 319
 320         if (copy_to_user(parg, ev, sizeof(*ev))) {
 321                 err = -EFAULT;
 322                 goto unlock;
 323         }
 324
 325         fh->pending_events &= ~(1 << ev->event);
 326
 327 unlock:
 328         mutex_unlock(&fh->lock);
 329         return err;
 330 }
 331
 332 static long cec_g_mode(struct cec_adapter *adap, struct cec_fh *fh,
 333                        u32 __user *parg)
 334 {
 335         u32 mode = fh->mode_initiator | fh->mode_follower;
 336
 337         if (copy_to_user(parg, &mode, sizeof(mode)))
 338                 return -EFAULT;
 339         return 0;
 340 }
 341
 342 static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
 343                        u32 __user *parg)
 344 {
 345         u32 mode;
 346         u8 mode_initiator;
 347         u8 mode_follower;
 348         long err = 0;
 349
 350         if (copy_from_user(&mode, parg, sizeof(mode)))
 351                 return -EFAULT;
 352         if (mode & ~(CEC_MODE_INITIATOR_MSK | CEC_MODE_FOLLOWER_MSK))
 353                 return -EINVAL;
 354
 355         mode_initiator = mode & CEC_MODE_INITIATOR_MSK;
 356         mode_follower = mode & CEC_MODE_FOLLOWER_MSK;
 357
 358         if (mode_initiator > CEC_MODE_EXCL_INITIATOR ||
 359             mode_follower > CEC_MODE_MONITOR_ALL)
 360                 return -EINVAL;
 361
 362         if (mode_follower == CEC_MODE_MONITOR_ALL &&
 363             !(adap->capabilities & CEC_CAP_MONITOR_ALL))
 364                 return -EINVAL;
 365
 366         /* Follower modes should always be able to send CEC messages */
 367         if ((mode_initiator == CEC_MODE_NO_INITIATOR ||
 368              !(adap->capabilities & CEC_CAP_TRANSMIT)) &&
 369             mode_follower >= CEC_MODE_FOLLOWER &&
 370             mode_follower <= CEC_MODE_EXCL_FOLLOWER_PASSTHRU)
 371                 return -EINVAL;
 372
 373         /* Monitor modes require CEC_MODE_NO_INITIATOR */
 374         if (mode_initiator && mode_follower >= CEC_MODE_MONITOR)
 375                 return -EINVAL;
 376
 377         /* Monitor modes require CAP_NET_ADMIN */
 378         if (mode_follower >= CEC_MODE_MONITOR && !capable(CAP_NET_ADMIN))
 379                 return -EPERM;
 380
 381         mutex_lock(&adap->lock);
 382         /*
 383          * You can't become exclusive follower if someone else already
 384          * has that job.
 385          */
 386         if ((mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 387              mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) &&
 388             adap->cec_follower && adap->cec_follower != fh)
 389                 err = -EBUSY;
 390         /*
 391          * You can't become exclusive initiator if someone else already
 392          * has that job.
 393          */
 394         if (mode_initiator == CEC_MODE_EXCL_INITIATOR &&
 395             adap->cec_initiator && adap->cec_initiator != fh)
 396                 err = -EBUSY;
 397
 398         if (!err) {
 399                 bool old_mon_all = fh->mode_follower == CEC_MODE_MONITOR_ALL;
 400                 bool new_mon_all = mode_follower == CEC_MODE_MONITOR_ALL;
 401
 402                 if (old_mon_all != new_mon_all) {
 403                         if (new_mon_all)
 404                                 err = cec_monitor_all_cnt_inc(adap);
 405                         else
 406                                 cec_monitor_all_cnt_dec(adap);
 407                 }
 408         }
 409
 410         if (err) {
 411                 mutex_unlock(&adap->lock);
 412                 return err;
 413         }
 414
 415         if (fh->mode_follower == CEC_MODE_FOLLOWER)
 416                 adap->follower_cnt--;
 417         if (mode_follower == CEC_MODE_FOLLOWER)
 418                 adap->follower_cnt++;
 419         if (mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 420             mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
 421                 adap->passthrough =
 422                         mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU;
 423                 adap->cec_follower = fh;
 424         } else if (adap->cec_follower == fh) {
 425                 adap->passthrough = false;
 426                 adap->cec_follower = NULL;
 427         }
 428         if (mode_initiator == CEC_MODE_EXCL_INITIATOR)
 429                 adap->cec_initiator = fh;
 430         else if (adap->cec_initiator == fh)
 431                 adap->cec_initiator = NULL;
 432         fh->mode_initiator = mode_initiator;
 433         fh->mode_follower = mode_follower;
 434         mutex_unlock(&adap->lock);
 435         return 0;
 436 }
 437
 438 static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 439 {
 440         struct cec_devnode *devnode = cec_devnode_data(filp);
 441         struct cec_fh *fh = filp->private_data;
 442         struct cec_adapter *adap = fh->adap;
 443         bool block = !(filp->f_flags & O_NONBLOCK);
 444         void __user *parg = (void __user *)arg;
 445
 446         if (!devnode->registered)
 447                 return -ENODEV;
 448
 449         switch (cmd) {
 450         case CEC_ADAP_G_CAPS:
 451                 return cec_adap_g_caps(adap, parg);
 452
 453         case CEC_ADAP_G_PHYS_ADDR:
 454                 return cec_adap_g_phys_addr(adap, parg);
 455
 456         case CEC_ADAP_S_PHYS_ADDR:
 457                 return cec_adap_s_phys_addr(adap, fh, block, parg);
 458
 459         case CEC_ADAP_G_LOG_ADDRS:
 460                 return cec_adap_g_log_addrs(adap, parg);
 461
 462         case CEC_ADAP_S_LOG_ADDRS:
 463                 return cec_adap_s_log_addrs(adap, fh, block, parg);
 464
 465         case CEC_TRANSMIT:
 466                 return cec_transmit(adap, fh, block, parg);
 467
 468         case CEC_RECEIVE:
 469                 return cec_receive(adap, fh, block, parg);
 470
 471         case CEC_DQEVENT:
 472                 return cec_dqevent(adap, fh, block, parg);
 473
 474         case CEC_G_MODE:
 475                 return cec_g_mode(adap, fh, parg);
 476
 477         case CEC_S_MODE:
 478                 return cec_s_mode(adap, fh, parg);
 479
 480         default:
 481                 return -ENOTTY;
 482         }
 483 }
 484
 485 static int cec_open(struct inode *inode, struct file *filp)
 486 {
 487         struct cec_devnode *devnode =
 488                 container_of(inode->i_cdev, struct cec_devnode, cdev);
 489         struct cec_adapter *adap = to_cec_adapter(devnode);
 490         struct cec_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
 491         /*
 492          * Initial events that are automatically sent when the cec device is
 493          * opened.
 494          */
 495         struct cec_event ev_state = {
 496                 .event = CEC_EVENT_STATE_CHANGE,
 497                 .flags = CEC_EVENT_FL_INITIAL_STATE,
 498         };
 499         int err;
 500
 501         if (!fh)
 502                 return -ENOMEM;
 503
 504         INIT_LIST_HEAD(&fh->msgs);
 505         INIT_LIST_HEAD(&fh->xfer_list);
 506         mutex_init(&fh->lock);
 507         init_waitqueue_head(&fh->wait);
 508
 509         fh->mode_initiator = CEC_MODE_INITIATOR;
 510         fh->adap = adap;
 511
 512         err = cec_get_device(devnode);
 513         if (err) {
 514                 kfree(fh);
 515                 return err;
 516         }
 517
 518         filp->private_data = fh;
 519
 520         mutex_lock(&devnode->lock);
 521         /* Queue up initial state events */
 522         ev_state.state_change.phys_addr = adap->phys_addr;
 523         ev_state.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
 524         cec_queue_event_fh(fh, &ev_state, 0);
 525
 526         list_add(&fh->list, &devnode->fhs);
 527         mutex_unlock(&devnode->lock);
 528
 529         return 0;
 530 }
 531
 532 /* Override for the release function */
 533 static int cec_release(struct inode *inode, struct file *filp)
 534 {
 535         struct cec_devnode *devnode = cec_devnode_data(filp);
 536         struct cec_adapter *adap = to_cec_adapter(devnode);
 537         struct cec_fh *fh = filp->private_data;
 538
 539         mutex_lock(&adap->lock);
 540         if (adap->cec_initiator == fh)
 541                 adap->cec_initiator = NULL;
 542         if (adap->cec_follower == fh) {
 543                 adap->cec_follower = NULL;
 544                 adap->passthrough = false;
 545         }
 546         if (fh->mode_follower == CEC_MODE_FOLLOWER)
 547                 adap->follower_cnt--;
 548         if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
 549                 cec_monitor_all_cnt_dec(adap);
 550         mutex_unlock(&adap->lock);
 551
 552         mutex_lock(&devnode->lock);
 553         list_del(&fh->list);
 554         mutex_unlock(&devnode->lock);
 555
 556         /* Unhook pending transmits from this filehandle. */
 557         mutex_lock(&adap->lock);
 558         while (!list_empty(&fh->xfer_list)) {
 559                 struct cec_data *data =
 560                         list_first_entry(&fh->xfer_list, struct cec_data, xfer_list);
 561
 562                 data->blocking = false;
 563                 data->fh = NULL;
 564                 list_del(&data->xfer_list);
 565         }
 566         mutex_unlock(&adap->lock);
 567         while (!list_empty(&fh->msgs)) {
 568                 struct cec_msg_entry *entry =
 569                         list_first_entry(&fh->msgs, struct cec_msg_entry, list);
 570
 571                 list_del(&entry->list);
 572                 kfree(entry);
 573         }
 574         kfree(fh);
 575
 576         cec_put_device(devnode);
 577         filp->private_data = NULL;
 578         return 0;
 579 }
 580
 581 const struct file_operations cec_devnode_fops = {
 582         .owner = THIS_MODULE,
 583         .open = cec_open,
 584         .unlocked_ioctl = cec_ioctl,
 585         .release = cec_release,
 586         .poll = cec_poll,
 587         .llseek = no_llseek,
 588 };