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                 res |= POLLOUT | POLLWRNORM;
  57         if (fh->queued_msgs)
  58                 res |= POLLIN | POLLRDNORM;
  59         if (fh->pending_events)
  60                 res |= POLLPRI;
  61         poll_wait(filp, &fh->wait, poll);
  62         mutex_unlock(&adap->lock);
  63         return res;
  64 }
  65
  66 static bool cec_is_busy(const struct cec_adapter *adap,
  67                         const struct cec_fh *fh)
  68 {
  69         bool valid_initiator = adap->cec_initiator && adap->cec_initiator == fh;
  70         bool valid_follower = adap->cec_follower && adap->cec_follower == fh;
  71
  72         /*
  73          * Exclusive initiators and followers can always access the CEC adapter
  74          */
  75         if (valid_initiator || valid_follower)
  76                 return false;
  77         /*
  78          * All others can only access the CEC adapter if there is no
  79          * exclusive initiator and they are in INITIATOR mode.
  80          */
  81         return adap->cec_initiator ||
  82                fh->mode_initiator == CEC_MODE_NO_INITIATOR;
  83 }
  84
  85 static long cec_adap_g_caps(struct cec_adapter *adap,
  86                             struct cec_caps __user *parg)
  87 {
  88         struct cec_caps caps = {};
  89
  90         strlcpy(caps.driver, adap->devnode.parent->driver->name,
  91                 sizeof(caps.driver));
  92         strlcpy(caps.name, adap->name, sizeof(caps.name));
  93         caps.available_log_addrs = adap->available_log_addrs;
  94         caps.capabilities = adap->capabilities;
  95         caps.version = LINUX_VERSION_CODE;
  96         if (copy_to_user(parg, &caps, sizeof(caps)))
  97                 return -EFAULT;
  98         return 0;
  99 }
 100
 101 static long cec_adap_g_phys_addr(struct cec_adapter *adap,
 102                                  __u16 __user *parg)
 103 {
 104         u16 phys_addr;
 105
 106         mutex_lock(&adap->lock);
 107         phys_addr = adap->phys_addr;
 108         mutex_unlock(&adap->lock);
 109         if (copy_to_user(parg, &phys_addr, sizeof(phys_addr)))
 110                 return -EFAULT;
 111         return 0;
 112 }
 113
 114 static long cec_adap_s_phys_addr(struct cec_adapter *adap, struct cec_fh *fh,
 115                                  bool block, __u16 __user *parg)
 116 {
 117         u16 phys_addr;
 118         long err;
 119
 120         if (!(adap->capabilities & CEC_CAP_PHYS_ADDR))
 121                 return -ENOTTY;
 122         if (copy_from_user(&phys_addr, parg, sizeof(phys_addr)))
 123                 return -EFAULT;
 124
 125         err = cec_phys_addr_validate(phys_addr, NULL, NULL);
 126         if (err)
 127                 return err;
 128         mutex_lock(&adap->lock);
 129         if (cec_is_busy(adap, fh))
 130                 err = -EBUSY;
 131         else
 132                 __cec_s_phys_addr(adap, phys_addr, block);
 133         mutex_unlock(&adap->lock);
 134         return err;
 135 }
 136
 137 static long cec_adap_g_log_addrs(struct cec_adapter *adap,
 138                                  struct cec_log_addrs __user *parg)
 139 {
 140         struct cec_log_addrs log_addrs;
 141
 142         mutex_lock(&adap->lock);
 143         log_addrs = adap->log_addrs;
 144         if (!adap->is_configured)
 145                 memset(log_addrs.log_addr, CEC_LOG_ADDR_INVALID,
 146                        sizeof(log_addrs.log_addr));
 147         mutex_unlock(&adap->lock);
 148
 149         if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
 150                 return -EFAULT;
 151         return 0;
 152 }
 153
 154 static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh,
 155                                  bool block, struct cec_log_addrs __user *parg)
 156 {
 157         struct cec_log_addrs log_addrs;
 158         long err = -EBUSY;
 159
 160         if (!(adap->capabilities & CEC_CAP_LOG_ADDRS))
 161                 return -ENOTTY;
 162         if (copy_from_user(&log_addrs, parg, sizeof(log_addrs)))
 163                 return -EFAULT;
 164         log_addrs.flags = 0;
 165         mutex_lock(&adap->lock);
 166         if (!adap->is_configuring &&
 167             (!log_addrs.num_log_addrs || !adap->is_configured) &&
 168             !cec_is_busy(adap, fh)) {
 169                 err = __cec_s_log_addrs(adap, &log_addrs, block);
 170                 if (!err)
 171                         log_addrs = adap->log_addrs;
 172         }
 173         mutex_unlock(&adap->lock);
 174         if (err)
 175                 return err;
 176         if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
 177                 return -EFAULT;
 178         return 0;
 179 }
 180
 181 static long cec_transmit(struct cec_adapter *adap, struct cec_fh *fh,
 182                          bool block, struct cec_msg __user *parg)
 183 {
 184         struct cec_msg msg = {};
 185         long err = 0;
 186
 187         if (!(adap->capabilities & CEC_CAP_TRANSMIT))
 188                 return -ENOTTY;
 189         if (copy_from_user(&msg, parg, sizeof(msg)))
 190                 return -EFAULT;
 191         mutex_lock(&adap->lock);
 192         if (!adap->is_configured) {
 193                 err = -ENONET;
 194         } else if (cec_is_busy(adap, fh)) {
 195                 err = -EBUSY;
 196         } else {
 197                 if (!block || !msg.reply)
 198                         fh = NULL;
 199                 err = cec_transmit_msg_fh(adap, &msg, fh, block);
 200         }
 201         mutex_unlock(&adap->lock);
 202         if (err)
 203                 return err;
 204         if (copy_to_user(parg, &msg, sizeof(msg)))
 205                 return -EFAULT;
 206         return 0;
 207 }
 208
 209 /* Called by CEC_RECEIVE: wait for a message to arrive */
 210 static int cec_receive_msg(struct cec_fh *fh, struct cec_msg *msg, bool block)
 211 {
 212         int res;
 213
 214         do {
 215                 mutex_lock(&fh->lock);
 216                 /* Are there received messages queued up? */
 217                 if (fh->queued_msgs) {
 218                         /* Yes, return the first one */
 219                         struct cec_msg_entry *entry =
 220                                 list_first_entry(&fh->msgs,
 221                                                  struct cec_msg_entry, list);
 222
 223                         list_del(&entry->list);
 224                         *msg = entry->msg;
 225                         kfree(entry);
 226                         fh->queued_msgs--;
 227                         mutex_unlock(&fh->lock);
 228                         return 0;
 229                 }
 230
 231                 /* No, return EAGAIN in non-blocking mode or wait */
 232                 mutex_unlock(&fh->lock);
 233
 234                 /* Return when in non-blocking mode */
 235                 if (!block)
 236                         return -EAGAIN;
 237
 238                 if (msg->timeout) {
 239                         /* The user specified a timeout */
 240                         res = wait_event_interruptible_timeout(fh->wait,
 241                                                                fh->queued_msgs,
 242                                 msecs_to_jiffies(msg->timeout));
 243                         if (res == 0)
 244                                 res = -ETIMEDOUT;
 245                         else if (res > 0)
 246                                 res = 0;
 247                 } else {
 248                         /* Wait indefinitely */
 249                         res = wait_event_interruptible(fh->wait,
 250                                                        fh->queued_msgs);
 251                 }
 252                 /* Exit on error, otherwise loop to get the new message */
 253         } while (!res);
 254         return res;
 255 }
 256
 257 static long cec_receive(struct cec_adapter *adap, struct cec_fh *fh,
 258                         bool block, struct cec_msg __user *parg)
 259 {
 260         struct cec_msg msg = {};
 261         long err = 0;
 262
 263         if (copy_from_user(&msg, parg, sizeof(msg)))
 264                 return -EFAULT;
 265         mutex_lock(&adap->lock);
 266         if (!adap->is_configured && fh->mode_follower < CEC_MODE_MONITOR)
 267                 err = -ENONET;
 268         mutex_unlock(&adap->lock);
 269         if (err)
 270                 return err;
 271
 272         err = cec_receive_msg(fh, &msg, block);
 273         if (err)
 274                 return err;
 275         if (copy_to_user(parg, &msg, sizeof(msg)))
 276                 return -EFAULT;
 277         return 0;
 278 }
 279
 280 static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
 281                         bool block, struct cec_event __user *parg)
 282 {
 283         struct cec_event *ev = NULL;
 284         u64 ts = ~0ULL;
 285         unsigned int i;
 286         long err = 0;
 287
 288         mutex_lock(&fh->lock);
 289         while (!fh->pending_events && block) {
 290                 mutex_unlock(&fh->lock);
 291                 err = wait_event_interruptible(fh->wait, fh->pending_events);
 292                 if (err)
 293                         return err;
 294                 mutex_lock(&fh->lock);
 295         }
 296
 297         /* Find the oldest event */
 298         for (i = 0; i < CEC_NUM_EVENTS; i++) {
 299                 if (fh->pending_events & (1 << (i + 1)) &&
 300                     fh->events[i].ts <= ts) {
 301                         ev = &fh->events[i];
 302                         ts = ev->ts;
 303                 }
 304         }
 305         if (!ev) {
 306                 err = -EAGAIN;
 307                 goto unlock;
 308         }
 309
 310         if (copy_to_user(parg, ev, sizeof(*ev))) {
 311                 err = -EFAULT;
 312                 goto unlock;
 313         }
 314
 315         fh->pending_events &= ~(1 << ev->event);
 316
 317 unlock:
 318         mutex_unlock(&fh->lock);
 319         return err;
 320 }
 321
 322 static long cec_g_mode(struct cec_adapter *adap, struct cec_fh *fh,
 323                        u32 __user *parg)
 324 {
 325         u32 mode = fh->mode_initiator | fh->mode_follower;
 326
 327         if (copy_to_user(parg, &mode, sizeof(mode)))
 328                 return -EFAULT;
 329         return 0;
 330 }
 331
 332 static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
 333                        u32 __user *parg)
 334 {
 335         u32 mode;
 336         u8 mode_initiator;
 337         u8 mode_follower;
 338         long err = 0;
 339
 340         if (copy_from_user(&mode, parg, sizeof(mode)))
 341                 return -EFAULT;
 342         if (mode & ~(CEC_MODE_INITIATOR_MSK | CEC_MODE_FOLLOWER_MSK))
 343                 return -EINVAL;
 344
 345         mode_initiator = mode & CEC_MODE_INITIATOR_MSK;
 346         mode_follower = mode & CEC_MODE_FOLLOWER_MSK;
 347
 348         if (mode_initiator > CEC_MODE_EXCL_INITIATOR ||
 349             mode_follower > CEC_MODE_MONITOR_ALL)
 350                 return -EINVAL;
 351
 352         if (mode_follower == CEC_MODE_MONITOR_ALL &&
 353             !(adap->capabilities & CEC_CAP_MONITOR_ALL))
 354                 return -EINVAL;
 355
 356         /* Follower modes should always be able to send CEC messages */
 357         if ((mode_initiator == CEC_MODE_NO_INITIATOR ||
 358              !(adap->capabilities & CEC_CAP_TRANSMIT)) &&
 359             mode_follower >= CEC_MODE_FOLLOWER &&
 360             mode_follower <= CEC_MODE_EXCL_FOLLOWER_PASSTHRU)
 361                 return -EINVAL;
 362
 363         /* Monitor modes require CEC_MODE_NO_INITIATOR */
 364         if (mode_initiator && mode_follower >= CEC_MODE_MONITOR)
 365                 return -EINVAL;
 366
 367         /* Monitor modes require CAP_NET_ADMIN */
 368         if (mode_follower >= CEC_MODE_MONITOR && !capable(CAP_NET_ADMIN))
 369                 return -EPERM;
 370
 371         mutex_lock(&adap->lock);
 372         /*
 373          * You can't become exclusive follower if someone else already
 374          * has that job.
 375          */
 376         if ((mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 377              mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) &&
 378             adap->cec_follower && adap->cec_follower != fh)
 379                 err = -EBUSY;
 380         /*
 381          * You can't become exclusive initiator if someone else already
 382          * has that job.
 383          */
 384         if (mode_initiator == CEC_MODE_EXCL_INITIATOR &&
 385             adap->cec_initiator && adap->cec_initiator != fh)
 386                 err = -EBUSY;
 387
 388         if (!err) {
 389                 bool old_mon_all = fh->mode_follower == CEC_MODE_MONITOR_ALL;
 390                 bool new_mon_all = mode_follower == CEC_MODE_MONITOR_ALL;
 391
 392                 if (old_mon_all != new_mon_all) {
 393                         if (new_mon_all)
 394                                 err = cec_monitor_all_cnt_inc(adap);
 395                         else
 396                                 cec_monitor_all_cnt_dec(adap);
 397                 }
 398         }
 399
 400         if (err) {
 401                 mutex_unlock(&adap->lock);
 402                 return err;
 403         }
 404
 405         if (fh->mode_follower == CEC_MODE_FOLLOWER)
 406                 adap->follower_cnt--;
 407         if (mode_follower == CEC_MODE_FOLLOWER)
 408                 adap->follower_cnt++;
 409         if (mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 410             mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
 411                 adap->passthrough =
 412                         mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU;
 413                 adap->cec_follower = fh;
 414         } else if (adap->cec_follower == fh) {
 415                 adap->passthrough = false;
 416                 adap->cec_follower = NULL;
 417         }
 418         if (mode_initiator == CEC_MODE_EXCL_INITIATOR)
 419                 adap->cec_initiator = fh;
 420         else if (adap->cec_initiator == fh)
 421                 adap->cec_initiator = NULL;
 422         fh->mode_initiator = mode_initiator;
 423         fh->mode_follower = mode_follower;
 424         mutex_unlock(&adap->lock);
 425         return 0;
 426 }
 427
 428 static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 429 {
 430         struct cec_devnode *devnode = cec_devnode_data(filp);
 431         struct cec_fh *fh = filp->private_data;
 432         struct cec_adapter *adap = fh->adap;
 433         bool block = !(filp->f_flags & O_NONBLOCK);
 434         void __user *parg = (void __user *)arg;
 435
 436         if (!devnode->registered)
 437                 return -EIO;
 438
 439         switch (cmd) {
 440         case CEC_ADAP_G_CAPS:
 441                 return cec_adap_g_caps(adap, parg);
 442
 443         case CEC_ADAP_G_PHYS_ADDR:
 444                 return cec_adap_g_phys_addr(adap, parg);
 445
 446         case CEC_ADAP_S_PHYS_ADDR:
 447                 return cec_adap_s_phys_addr(adap, fh, block, parg);
 448
 449         case CEC_ADAP_G_LOG_ADDRS:
 450                 return cec_adap_g_log_addrs(adap, parg);
 451
 452         case CEC_ADAP_S_LOG_ADDRS:
 453                 return cec_adap_s_log_addrs(adap, fh, block, parg);
 454
 455         case CEC_TRANSMIT:
 456                 return cec_transmit(adap, fh, block, parg);
 457
 458         case CEC_RECEIVE:
 459                 return cec_receive(adap, fh, block, parg);
 460
 461         case CEC_DQEVENT:
 462                 return cec_dqevent(adap, fh, block, parg);
 463
 464         case CEC_G_MODE:
 465                 return cec_g_mode(adap, fh, parg);
 466
 467         case CEC_S_MODE:
 468                 return cec_s_mode(adap, fh, parg);
 469
 470         default:
 471                 return -ENOTTY;
 472         }
 473 }
 474
 475 static int cec_open(struct inode *inode, struct file *filp)
 476 {
 477         struct cec_devnode *devnode =
 478                 container_of(inode->i_cdev, struct cec_devnode, cdev);
 479         struct cec_adapter *adap = to_cec_adapter(devnode);
 480         struct cec_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
 481         /*
 482          * Initial events that are automatically sent when the cec device is
 483          * opened.
 484          */
 485         struct cec_event ev_state = {
 486                 .event = CEC_EVENT_STATE_CHANGE,
 487                 .flags = CEC_EVENT_FL_INITIAL_STATE,
 488         };
 489         int err;
 490
 491         if (!fh)
 492                 return -ENOMEM;
 493
 494         INIT_LIST_HEAD(&fh->msgs);
 495         INIT_LIST_HEAD(&fh->xfer_list);
 496         mutex_init(&fh->lock);
 497         init_waitqueue_head(&fh->wait);
 498
 499         fh->mode_initiator = CEC_MODE_INITIATOR;
 500         fh->adap = adap;
 501
 502         err = cec_get_device(devnode);
 503         if (err) {
 504                 kfree(fh);
 505                 return err;
 506         }
 507
 508         filp->private_data = fh;
 509
 510         mutex_lock(&devnode->fhs_lock);
 511         /* Queue up initial state events */
 512         ev_state.state_change.phys_addr = adap->phys_addr;
 513         ev_state.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
 514         cec_queue_event_fh(fh, &ev_state, 0);
 515
 516         list_add(&fh->list, &devnode->fhs);
 517         mutex_unlock(&devnode->fhs_lock);
 518
 519         return 0;
 520 }
 521
 522 /* Override for the release function */
 523 static int cec_release(struct inode *inode, struct file *filp)
 524 {
 525         struct cec_devnode *devnode = cec_devnode_data(filp);
 526         struct cec_adapter *adap = to_cec_adapter(devnode);
 527         struct cec_fh *fh = filp->private_data;
 528
 529         mutex_lock(&adap->lock);
 530         if (adap->cec_initiator == fh)
 531                 adap->cec_initiator = NULL;
 532         if (adap->cec_follower == fh) {
 533                 adap->cec_follower = NULL;
 534                 adap->passthrough = false;
 535         }
 536         if (fh->mode_follower == CEC_MODE_FOLLOWER)
 537                 adap->follower_cnt--;
 538         if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
 539                 cec_monitor_all_cnt_dec(adap);
 540         mutex_unlock(&adap->lock);
 541
 542         mutex_lock(&devnode->fhs_lock);
 543         list_del(&fh->list);
 544         mutex_unlock(&devnode->fhs_lock);
 545
 546         /* Unhook pending transmits from this filehandle. */
 547         mutex_lock(&adap->lock);
 548         while (!list_empty(&fh->xfer_list)) {
 549                 struct cec_data *data =
 550                         list_first_entry(&fh->xfer_list, struct cec_data, xfer_list);
 551
 552                 data->blocking = false;
 553                 data->fh = NULL;
 554                 list_del(&data->xfer_list);
 555         }
 556         mutex_unlock(&adap->lock);
 557         while (!list_empty(&fh->msgs)) {
 558                 struct cec_msg_entry *entry =
 559                         list_first_entry(&fh->msgs, struct cec_msg_entry, list);
 560
 561                 list_del(&entry->list);
 562                 kfree(entry);
 563         }
 564         kfree(fh);
 565
 566         cec_put_device(devnode);
 567         filp->private_data = NULL;
 568         return 0;
 569 }
 570
 571 const struct file_operations cec_devnode_fops = {
 572         .owner = THIS_MODULE,
 573         .open = cec_open,
 574         .unlocked_ioctl = cec_ioctl,
 575         .release = cec_release,
 576         .poll = cec_poll,
 577         .llseek = no_llseek,
 578 };