drivers/staging/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.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         mutex_lock(&adap->lock);
 167         if (!adap->is_configuring &&
 168             (!log_addrs.num_log_addrs || !adap->is_configured) &&
 169             !cec_is_busy(adap, fh)) {
 170                 err = __cec_s_log_addrs(adap, &log_addrs, block);
 171                 if (!err)
 172                         log_addrs = adap->log_addrs;
 173         }
 174         mutex_unlock(&adap->lock);
 175         if (err)
 176                 return err;
 177         if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
 178                 return -EFAULT;
 179         return 0;
 180 }
 181
 182 static long cec_transmit(struct cec_adapter *adap, struct cec_fh *fh,
 183                          bool block, struct cec_msg __user *parg)
 184 {
 185         struct cec_msg msg = {};
 186         long err = 0;
 187
 188         if (!(adap->capabilities & CEC_CAP_TRANSMIT))
 189                 return -ENOTTY;
 190         if (copy_from_user(&msg, parg, sizeof(msg)))
 191                 return -EFAULT;
 192         mutex_lock(&adap->lock);
 193         if (!adap->is_configured)
 194                 err = -ENONET;
 195         else if (cec_is_busy(adap, fh))
 196                 err = -EBUSY;
 197         else
 198                 err = cec_transmit_msg_fh(adap, &msg, fh, block);
 199         mutex_unlock(&adap->lock);
 200         if (err)
 201                 return err;
 202         if (copy_to_user(parg, &msg, sizeof(msg)))
 203                 return -EFAULT;
 204         return 0;
 205 }
 206
 207 /* Called by CEC_RECEIVE: wait for a message to arrive */
 208 static int cec_receive_msg(struct cec_fh *fh, struct cec_msg *msg, bool block)
 209 {
 210         u32 timeout = msg->timeout;
 211         int res;
 212
 213         do {
 214                 mutex_lock(&fh->lock);
 215                 /* Are there received messages queued up? */
 216                 if (fh->queued_msgs) {
 217                         /* Yes, return the first one */
 218                         struct cec_msg_entry *entry =
 219                                 list_first_entry(&fh->msgs,
 220                                                  struct cec_msg_entry, list);
 221
 222                         list_del(&entry->list);
 223                         *msg = entry->msg;
 224                         kfree(entry);
 225                         fh->queued_msgs--;
 226                         mutex_unlock(&fh->lock);
 227                         /* restore original timeout value */
 228                         msg->timeout = timeout;
 229                         return 0;
 230                 }
 231
 232                 /* No, return EAGAIN in non-blocking mode or wait */
 233                 mutex_unlock(&fh->lock);
 234
 235                 /* Return when in non-blocking mode */
 236                 if (!block)
 237                         return -EAGAIN;
 238
 239                 if (msg->timeout) {
 240                         /* The user specified a timeout */
 241                         res = wait_event_interruptible_timeout(fh->wait,
 242                                                                fh->queued_msgs,
 243                                 msecs_to_jiffies(msg->timeout));
 244                         if (res == 0)
 245                                 res = -ETIMEDOUT;
 246                         else if (res > 0)
 247                                 res = 0;
 248                 } else {
 249                         /* Wait indefinitely */
 250                         res = wait_event_interruptible(fh->wait,
 251                                                        fh->queued_msgs);
 252                 }
 253                 /* Exit on error, otherwise loop to get the new message */
 254         } while (!res);
 255         return res;
 256 }
 257
 258 static long cec_receive(struct cec_adapter *adap, struct cec_fh *fh,
 259                         bool block, struct cec_msg __user *parg)
 260 {
 261         struct cec_msg msg = {};
 262         long err = 0;
 263
 264         if (copy_from_user(&msg, parg, sizeof(msg)))
 265                 return -EFAULT;
 266         mutex_lock(&adap->lock);
 267         if (!adap->is_configured && fh->mode_follower < CEC_MODE_MONITOR)
 268                 err = -ENONET;
 269         mutex_unlock(&adap->lock);
 270         if (err)
 271                 return err;
 272
 273         err = cec_receive_msg(fh, &msg, block);
 274         if (err)
 275                 return err;
 276         if (copy_to_user(parg, &msg, sizeof(msg)))
 277                 return -EFAULT;
 278         return 0;
 279 }
 280
 281 static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
 282                         bool block, struct cec_event __user *parg)
 283 {
 284         struct cec_event *ev = NULL;
 285         u64 ts = ~0ULL;
 286         unsigned int i;
 287         long err = 0;
 288
 289         mutex_lock(&fh->lock);
 290         while (!fh->pending_events && block) {
 291                 mutex_unlock(&fh->lock);
 292                 err = wait_event_interruptible(fh->wait, fh->pending_events);
 293                 if (err)
 294                         return err;
 295                 mutex_lock(&fh->lock);
 296         }
 297
 298         /* Find the oldest event */
 299         for (i = 0; i < CEC_NUM_EVENTS; i++) {
 300                 if (fh->pending_events & (1 << (i + 1)) &&
 301                     fh->events[i].ts <= ts) {
 302                         ev = &fh->events[i];
 303                         ts = ev->ts;
 304                 }
 305         }
 306         if (!ev) {
 307                 err = -EAGAIN;
 308                 goto unlock;
 309         }
 310
 311         if (copy_to_user(parg, ev, sizeof(*ev))) {
 312                 err = -EFAULT;
 313                 goto unlock;
 314         }
 315
 316         fh->pending_events &= ~(1 << ev->event);
 317
 318 unlock:
 319         mutex_unlock(&fh->lock);
 320         return err;
 321 }
 322
 323 static long cec_g_mode(struct cec_adapter *adap, struct cec_fh *fh,
 324                        u32 __user *parg)
 325 {
 326         u32 mode = fh->mode_initiator | fh->mode_follower;
 327
 328         if (copy_to_user(parg, &mode, sizeof(mode)))
 329                 return -EFAULT;
 330         return 0;
 331 }
 332
 333 static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
 334                        u32 __user *parg)
 335 {
 336         u32 mode;
 337         u8 mode_initiator;
 338         u8 mode_follower;
 339         long err = 0;
 340
 341         if (copy_from_user(&mode, parg, sizeof(mode)))
 342                 return -EFAULT;
 343         if (mode & ~(CEC_MODE_INITIATOR_MSK | CEC_MODE_FOLLOWER_MSK))
 344                 return -EINVAL;
 345
 346         mode_initiator = mode & CEC_MODE_INITIATOR_MSK;
 347         mode_follower = mode & CEC_MODE_FOLLOWER_MSK;
 348
 349         if (mode_initiator > CEC_MODE_EXCL_INITIATOR ||
 350             mode_follower > CEC_MODE_MONITOR_ALL)
 351                 return -EINVAL;
 352
 353         if (mode_follower == CEC_MODE_MONITOR_ALL &&
 354             !(adap->capabilities & CEC_CAP_MONITOR_ALL))
 355                 return -EINVAL;
 356
 357         /* Follower modes should always be able to send CEC messages */
 358         if ((mode_initiator == CEC_MODE_NO_INITIATOR ||
 359              !(adap->capabilities & CEC_CAP_TRANSMIT)) &&
 360             mode_follower >= CEC_MODE_FOLLOWER &&
 361             mode_follower <= CEC_MODE_EXCL_FOLLOWER_PASSTHRU)
 362                 return -EINVAL;
 363
 364         /* Monitor modes require CEC_MODE_NO_INITIATOR */
 365         if (mode_initiator && mode_follower >= CEC_MODE_MONITOR)
 366                 return -EINVAL;
 367
 368         /* Monitor modes require CAP_NET_ADMIN */
 369         if (mode_follower >= CEC_MODE_MONITOR && !capable(CAP_NET_ADMIN))
 370                 return -EPERM;
 371
 372         mutex_lock(&adap->lock);
 373         /*
 374          * You can't become exclusive follower if someone else already
 375          * has that job.
 376          */
 377         if ((mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 378              mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) &&
 379             adap->cec_follower && adap->cec_follower != fh)
 380                 err = -EBUSY;
 381         /*
 382          * You can't become exclusive initiator if someone else already
 383          * has that job.
 384          */
 385         if (mode_initiator == CEC_MODE_EXCL_INITIATOR &&
 386             adap->cec_initiator && adap->cec_initiator != fh)
 387                 err = -EBUSY;
 388
 389         if (!err) {
 390                 bool old_mon_all = fh->mode_follower == CEC_MODE_MONITOR_ALL;
 391                 bool new_mon_all = mode_follower == CEC_MODE_MONITOR_ALL;
 392
 393                 if (old_mon_all != new_mon_all) {
 394                         if (new_mon_all)
 395                                 err = cec_monitor_all_cnt_inc(adap);
 396                         else
 397                                 cec_monitor_all_cnt_dec(adap);
 398                 }
 399         }
 400
 401         if (err) {
 402                 mutex_unlock(&adap->lock);
 403                 return err;
 404         }
 405
 406         if (fh->mode_follower == CEC_MODE_FOLLOWER)
 407                 adap->follower_cnt--;
 408         if (mode_follower == CEC_MODE_FOLLOWER)
 409                 adap->follower_cnt++;
 410         if (mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 411             mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
 412                 adap->passthrough =
 413                         mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU;
 414                 adap->cec_follower = fh;
 415         } else if (adap->cec_follower == fh) {
 416                 adap->passthrough = false;
 417                 adap->cec_follower = NULL;
 418         }
 419         if (mode_initiator == CEC_MODE_EXCL_INITIATOR)
 420                 adap->cec_initiator = fh;
 421         else if (adap->cec_initiator == fh)
 422                 adap->cec_initiator = NULL;
 423         fh->mode_initiator = mode_initiator;
 424         fh->mode_follower = mode_follower;
 425         mutex_unlock(&adap->lock);
 426         return 0;
 427 }
 428
 429 static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 430 {
 431         struct cec_devnode *devnode = cec_devnode_data(filp);
 432         struct cec_fh *fh = filp->private_data;
 433         struct cec_adapter *adap = fh->adap;
 434         bool block = !(filp->f_flags & O_NONBLOCK);
 435         void __user *parg = (void __user *)arg;
 436
 437         if (!devnode->registered)
 438                 return -ENODEV;
 439
 440         switch (cmd) {
 441         case CEC_ADAP_G_CAPS:
 442                 return cec_adap_g_caps(adap, parg);
 443
 444         case CEC_ADAP_G_PHYS_ADDR:
 445                 return cec_adap_g_phys_addr(adap, parg);
 446
 447         case CEC_ADAP_S_PHYS_ADDR:
 448                 return cec_adap_s_phys_addr(adap, fh, block, parg);
 449
 450         case CEC_ADAP_G_LOG_ADDRS:
 451                 return cec_adap_g_log_addrs(adap, parg);
 452
 453         case CEC_ADAP_S_LOG_ADDRS:
 454                 return cec_adap_s_log_addrs(adap, fh, block, parg);
 455
 456         case CEC_TRANSMIT:
 457                 return cec_transmit(adap, fh, block, parg);
 458
 459         case CEC_RECEIVE:
 460                 return cec_receive(adap, fh, block, parg);
 461
 462         case CEC_DQEVENT:
 463                 return cec_dqevent(adap, fh, block, parg);
 464
 465         case CEC_G_MODE:
 466                 return cec_g_mode(adap, fh, parg);
 467
 468         case CEC_S_MODE:
 469                 return cec_s_mode(adap, fh, parg);
 470
 471         default:
 472                 return -ENOTTY;
 473         }
 474 }
 475
 476 static int cec_open(struct inode *inode, struct file *filp)
 477 {
 478         struct cec_devnode *devnode =
 479                 container_of(inode->i_cdev, struct cec_devnode, cdev);
 480         struct cec_adapter *adap = to_cec_adapter(devnode);
 481         struct cec_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
 482         /*
 483          * Initial events that are automatically sent when the cec device is
 484          * opened.
 485          */
 486         struct cec_event ev_state = {
 487                 .event = CEC_EVENT_STATE_CHANGE,
 488                 .flags = CEC_EVENT_FL_INITIAL_STATE,
 489         };
 490         int err;
 491
 492         if (!fh)
 493                 return -ENOMEM;
 494
 495         INIT_LIST_HEAD(&fh->msgs);
 496         INIT_LIST_HEAD(&fh->xfer_list);
 497         mutex_init(&fh->lock);
 498         init_waitqueue_head(&fh->wait);
 499
 500         fh->mode_initiator = CEC_MODE_INITIATOR;
 501         fh->adap = adap;
 502
 503         err = cec_get_device(devnode);
 504         if (err) {
 505                 kfree(fh);
 506                 return err;
 507         }
 508
 509         filp->private_data = fh;
 510
 511         mutex_lock(&devnode->lock);
 512         /* Queue up initial state events */
 513         ev_state.state_change.phys_addr = adap->phys_addr;
 514         ev_state.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
 515         cec_queue_event_fh(fh, &ev_state, 0);
 516
 517         list_add(&fh->list, &devnode->fhs);
 518         mutex_unlock(&devnode->lock);
 519
 520         return 0;
 521 }
 522
 523 /* Override for the release function */
 524 static int cec_release(struct inode *inode, struct file *filp)
 525 {
 526         struct cec_devnode *devnode = cec_devnode_data(filp);
 527         struct cec_adapter *adap = to_cec_adapter(devnode);
 528         struct cec_fh *fh = filp->private_data;
 529
 530         mutex_lock(&adap->lock);
 531         if (adap->cec_initiator == fh)
 532                 adap->cec_initiator = NULL;
 533         if (adap->cec_follower == fh) {
 534                 adap->cec_follower = NULL;
 535                 adap->passthrough = false;
 536         }
 537         if (fh->mode_follower == CEC_MODE_FOLLOWER)
 538                 adap->follower_cnt--;
 539         if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
 540                 cec_monitor_all_cnt_dec(adap);
 541         mutex_unlock(&adap->lock);
 542
 543         mutex_lock(&devnode->lock);
 544         list_del(&fh->list);
 545         mutex_unlock(&devnode->lock);
 546
 547         /* Unhook pending transmits from this filehandle. */
 548         mutex_lock(&adap->lock);
 549         while (!list_empty(&fh->xfer_list)) {
 550                 struct cec_data *data =
 551                         list_first_entry(&fh->xfer_list, struct cec_data, xfer_list);
 552
 553                 data->blocking = false;
 554                 data->fh = NULL;
 555                 list_del(&data->xfer_list);
 556         }
 557         mutex_unlock(&adap->lock);
 558         while (!list_empty(&fh->msgs)) {
 559                 struct cec_msg_entry *entry =
 560                         list_first_entry(&fh->msgs, struct cec_msg_entry, list);
 561
 562                 list_del(&entry->list);
 563                 kfree(entry);
 564         }
 565         kfree(fh);
 566
 567         cec_put_device(devnode);
 568         filp->private_data = NULL;
 569         return 0;
 570 }
 571
 572 const struct file_operations cec_devnode_fops = {
 573         .owner = THIS_MODULE,
 574         .open = cec_open,
 575         .unlocked_ioctl = cec_ioctl,
 576         .release = cec_release,
 577         .poll = cec_poll,
 578         .llseek = no_llseek,
 579 };