drivers/rpmsg/rpmsg_char.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2016, Linaro Ltd.
   4  * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
   5  * Copyright (c) 2012, PetaLogix
   6  * Copyright (c) 2011, Texas Instruments, Inc.
   7  * Copyright (c) 2011, Google, Inc.
   8  *
   9  * Based on rpmsg performance statistics driver by Michal Simek, which in turn
  10  * was based on TI & Google OMX rpmsg driver.
  11  */
  12 #include <linux/cdev.h>
  13 #include <linux/device.h>
  14 #include <linux/fs.h>
  15 #include <linux/idr.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/poll.h>
  19 #include <linux/rpmsg.h>
  20 #include <linux/skbuff.h>
  21 #include <linux/slab.h>
  22 #include <linux/uaccess.h>
  23 #include <uapi/linux/rpmsg.h>
  24
  25 #include "rpmsg_internal.h"
  26
  27 #define RPMSG_DEV_MAX   (MINORMASK + 1)
  28
  29 static dev_t rpmsg_major;
  30 static struct class *rpmsg_class;
  31
  32 static DEFINE_IDA(rpmsg_ctrl_ida);
  33 static DEFINE_IDA(rpmsg_ept_ida);
  34 static DEFINE_IDA(rpmsg_minor_ida);
  35
  36 #define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
  37 #define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)
  38
  39 #define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
  40 #define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
  41
  42 /**
  43  * struct rpmsg_ctrldev - control device for instantiating endpoint devices
  44  * @rpdev:      underlaying rpmsg device
  45  * @cdev:       cdev for the ctrl device
  46  * @dev:        device for the ctrl device
  47  */
  48 struct rpmsg_ctrldev {
  49         struct rpmsg_device *rpdev;
  50         struct cdev cdev;
  51         struct device dev;
  52 };
  53
  54 /**
  55  * struct rpmsg_eptdev - endpoint device context
  56  * @dev:        endpoint device
  57  * @cdev:       cdev for the endpoint device
  58  * @rpdev:      underlaying rpmsg device
  59  * @chinfo:     info used to open the endpoint
  60  * @ept_lock:   synchronization of @ept modifications
  61  * @ept:        rpmsg endpoint reference, when open
  62  * @queue_lock: synchronization of @queue operations
  63  * @queue:      incoming message queue
  64  * @readq:      wait object for incoming queue
  65  */
  66 struct rpmsg_eptdev {
  67         struct device dev;
  68         struct cdev cdev;
  69
  70         struct rpmsg_device *rpdev;
  71         struct rpmsg_channel_info chinfo;
  72
  73         struct mutex ept_lock;
  74         struct rpmsg_endpoint *ept;
  75
  76         spinlock_t queue_lock;
  77         struct sk_buff_head queue;
  78         wait_queue_head_t readq;
  79 };
  80
  81 static int rpmsg_eptdev_destroy(struct device *dev, void *data)
  82 {
  83         struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
  84
  85         mutex_lock(&eptdev->ept_lock);
  86         if (eptdev->ept) {
  87                 rpmsg_destroy_ept(eptdev->ept);
  88                 eptdev->ept = NULL;
  89         }
  90         mutex_unlock(&eptdev->ept_lock);
  91
  92         /* wake up any blocked readers */
  93         wake_up_interruptible(&eptdev->readq);
  94
  95         device_del(&eptdev->dev);
  96         put_device(&eptdev->dev);
  97
  98         return 0;
  99 }
 100
 101 static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
 102                         void *priv, u32 addr)
 103 {
 104         struct rpmsg_eptdev *eptdev = priv;
 105         struct sk_buff *skb;
 106
 107         skb = alloc_skb(len, GFP_ATOMIC);
 108         if (!skb)
 109                 return -ENOMEM;
 110
 111         skb_put_data(skb, buf, len);
 112
 113         spin_lock(&eptdev->queue_lock);
 114         skb_queue_tail(&eptdev->queue, skb);
 115         spin_unlock(&eptdev->queue_lock);
 116
 117         /* wake up any blocking processes, waiting for new data */
 118         wake_up_interruptible(&eptdev->readq);
 119
 120         return 0;
 121 }
 122
 123 static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 124 {
 125         struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
 126         struct rpmsg_endpoint *ept;
 127         struct rpmsg_device *rpdev = eptdev->rpdev;
 128         struct device *dev = &eptdev->dev;
 129
 130         get_device(dev);
 131
 132         ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
 133         if (!ept) {
 134                 dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
 135                 put_device(dev);
 136                 return -EINVAL;
 137         }
 138
 139         eptdev->ept = ept;
 140         filp->private_data = eptdev;
 141
 142         return 0;
 143 }
 144
 145 static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
 146 {
 147         struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
 148         struct device *dev = &eptdev->dev;
 149
 150         /* Close the endpoint, if it's not already destroyed by the parent */
 151         mutex_lock(&eptdev->ept_lock);
 152         if (eptdev->ept) {
 153                 rpmsg_destroy_ept(eptdev->ept);
 154                 eptdev->ept = NULL;
 155         }
 156         mutex_unlock(&eptdev->ept_lock);
 157
 158         /* Discard all SKBs */
 159         skb_queue_purge(&eptdev->queue);
 160
 161         put_device(dev);
 162
 163         return 0;
 164 }
 165
 166 static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 167 {
 168         struct file *filp = iocb->ki_filp;
 169         struct rpmsg_eptdev *eptdev = filp->private_data;
 170         unsigned long flags;
 171         struct sk_buff *skb;
 172         int use;
 173
 174         if (!eptdev->ept)
 175                 return -EPIPE;
 176
 177         spin_lock_irqsave(&eptdev->queue_lock, flags);
 178
 179         /* Wait for data in the queue */
 180         if (skb_queue_empty(&eptdev->queue)) {
 181                 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
 182
 183                 if (filp->f_flags & O_NONBLOCK)
 184                         return -EAGAIN;
 185
 186                 /* Wait until we get data or the endpoint goes away */
 187                 if (wait_event_interruptible(eptdev->readq,
 188                                              !skb_queue_empty(&eptdev->queue) ||
 189                                              !eptdev->ept))
 190                         return -ERESTARTSYS;
 191
 192                 /* We lost the endpoint while waiting */
 193                 if (!eptdev->ept)
 194                         return -EPIPE;
 195
 196                 spin_lock_irqsave(&eptdev->queue_lock, flags);
 197         }
 198
 199         skb = skb_dequeue(&eptdev->queue);
 200         spin_unlock_irqrestore(&eptdev->queue_lock, flags);
 201         if (!skb)
 202                 return -EFAULT;
 203
 204         use = min_t(size_t, iov_iter_count(to), skb->len);
 205         if (copy_to_iter(skb->data, use, to) != use)
 206                 use = -EFAULT;
 207
 208         kfree_skb(skb);
 209
 210         return use;
 211 }
 212
 213 static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
 214                                        struct iov_iter *from)
 215 {
 216         struct file *filp = iocb->ki_filp;
 217         struct rpmsg_eptdev *eptdev = filp->private_data;
 218         size_t len = iov_iter_count(from);
 219         void *kbuf;
 220         int ret;
 221
 222         kbuf = kzalloc(len, GFP_KERNEL);
 223         if (!kbuf)
 224                 return -ENOMEM;
 225
 226         if (!copy_from_iter_full(kbuf, len, from)) {
 227                 ret = -EFAULT;
 228                 goto free_kbuf;
 229         }
 230
 231         if (mutex_lock_interruptible(&eptdev->ept_lock)) {
 232                 ret = -ERESTARTSYS;
 233                 goto free_kbuf;
 234         }
 235
 236         if (!eptdev->ept) {
 237                 ret = -EPIPE;
 238                 goto unlock_eptdev;
 239         }
 240
 241         if (filp->f_flags & O_NONBLOCK)
 242                 ret = rpmsg_trysend(eptdev->ept, kbuf, len);
 243         else
 244                 ret = rpmsg_send(eptdev->ept, kbuf, len);
 245
 246 unlock_eptdev:
 247         mutex_unlock(&eptdev->ept_lock);
 248
 249 free_kbuf:
 250         kfree(kbuf);
 251         return ret < 0 ? ret : len;
 252 }
 253
 254 static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 255 {
 256         struct rpmsg_eptdev *eptdev = filp->private_data;
 257         __poll_t mask = 0;
 258
 259         if (!eptdev->ept)
 260                 return EPOLLERR;
 261
 262         poll_wait(filp, &eptdev->readq, wait);
 263
 264         if (!skb_queue_empty(&eptdev->queue))
 265                 mask |= EPOLLIN | EPOLLRDNORM;
 266
 267         mask |= rpmsg_poll(eptdev->ept, filp, wait);
 268
 269         return mask;
 270 }
 271
 272 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 273                                unsigned long arg)
 274 {
 275         struct rpmsg_eptdev *eptdev = fp->private_data;
 276
 277         if (cmd != RPMSG_DESTROY_EPT_IOCTL)
 278                 return -EINVAL;
 279
 280         return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
 281 }
 282
 283 static const struct file_operations rpmsg_eptdev_fops = {
 284         .owner = THIS_MODULE,
 285         .open = rpmsg_eptdev_open,
 286         .release = rpmsg_eptdev_release,
 287         .read_iter = rpmsg_eptdev_read_iter,
 288         .write_iter = rpmsg_eptdev_write_iter,
 289         .poll = rpmsg_eptdev_poll,
 290         .unlocked_ioctl = rpmsg_eptdev_ioctl,
 291         .compat_ioctl = compat_ptr_ioctl,
 292 };
 293
 294 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 295                          char *buf)
 296 {
 297         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 298
 299         return sprintf(buf, "%s\n", eptdev->chinfo.name);
 300 }
 301 static DEVICE_ATTR_RO(name);
 302
 303 static ssize_t src_show(struct device *dev, struct device_attribute *attr,
 304                          char *buf)
 305 {
 306         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 307
 308         return sprintf(buf, "%d\n", eptdev->chinfo.src);
 309 }
 310 static DEVICE_ATTR_RO(src);
 311
 312 static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
 313                          char *buf)
 314 {
 315         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 316
 317         return sprintf(buf, "%d\n", eptdev->chinfo.dst);
 318 }
 319 static DEVICE_ATTR_RO(dst);
 320
 321 static struct attribute *rpmsg_eptdev_attrs[] = {
 322         &dev_attr_name.attr,
 323         &dev_attr_src.attr,
 324         &dev_attr_dst.attr,
 325         NULL
 326 };
 327 ATTRIBUTE_GROUPS(rpmsg_eptdev);
 328
 329 static void rpmsg_eptdev_release_device(struct device *dev)
 330 {
 331         struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
 332
 333         ida_simple_remove(&rpmsg_ept_ida, dev->id);
 334         ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
 335         cdev_del(&eptdev->cdev);
 336         kfree(eptdev);
 337 }
 338
 339 static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
 340                                struct rpmsg_channel_info chinfo)
 341 {
 342         struct rpmsg_device *rpdev = ctrldev->rpdev;
 343         struct rpmsg_eptdev *eptdev;
 344         struct device *dev;
 345         int ret;
 346
 347         eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
 348         if (!eptdev)
 349                 return -ENOMEM;
 350
 351         dev = &eptdev->dev;
 352         eptdev->rpdev = rpdev;
 353         eptdev->chinfo = chinfo;
 354
 355         mutex_init(&eptdev->ept_lock);
 356         spin_lock_init(&eptdev->queue_lock);
 357         skb_queue_head_init(&eptdev->queue);
 358         init_waitqueue_head(&eptdev->readq);
 359
 360         device_initialize(dev);
 361         dev->class = rpmsg_class;
 362         dev->parent = &ctrldev->dev;
 363         dev->groups = rpmsg_eptdev_groups;
 364         dev_set_drvdata(dev, eptdev);
 365
 366         cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
 367         eptdev->cdev.owner = THIS_MODULE;
 368
 369         ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
 370         if (ret < 0)
 371                 goto free_eptdev;
 372         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
 373
 374         ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
 375         if (ret < 0)
 376                 goto free_minor_ida;
 377         dev->id = ret;
 378         dev_set_name(dev, "rpmsg%d", ret);
 379
 380         ret = cdev_add(&eptdev->cdev, dev->devt, 1);
 381         if (ret)
 382                 goto free_ept_ida;
 383
 384         /* We can now rely on the release function for cleanup */
 385         dev->release = rpmsg_eptdev_release_device;
 386
 387         ret = device_add(dev);
 388         if (ret) {
 389                 dev_err(dev, "device_add failed: %d\n", ret);
 390                 put_device(dev);
 391         }
 392
 393         return ret;
 394
 395 free_ept_ida:
 396         ida_simple_remove(&rpmsg_ept_ida, dev->id);
 397 free_minor_ida:
 398         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 399 free_eptdev:
 400         put_device(dev);
 401         kfree(eptdev);
 402
 403         return ret;
 404 }
 405
 406 static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
 407 {
 408         struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
 409
 410         get_device(&ctrldev->dev);
 411         filp->private_data = ctrldev;
 412
 413         return 0;
 414 }
 415
 416 static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
 417 {
 418         struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
 419
 420         put_device(&ctrldev->dev);
 421
 422         return 0;
 423 }
 424
 425 static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
 426                                 unsigned long arg)
 427 {
 428         struct rpmsg_ctrldev *ctrldev = fp->private_data;
 429         void __user *argp = (void __user *)arg;
 430         struct rpmsg_endpoint_info eptinfo;
 431         struct rpmsg_channel_info chinfo;
 432
 433         if (cmd != RPMSG_CREATE_EPT_IOCTL)
 434                 return -EINVAL;
 435
 436         if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
 437                 return -EFAULT;
 438
 439         memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
 440         chinfo.name[RPMSG_NAME_SIZE-1] = '\0';
 441         chinfo.src = eptinfo.src;
 442         chinfo.dst = eptinfo.dst;
 443
 444         return rpmsg_eptdev_create(ctrldev, chinfo);
 445 };
 446
 447 static const struct file_operations rpmsg_ctrldev_fops = {
 448         .owner = THIS_MODULE,
 449         .open = rpmsg_ctrldev_open,
 450         .release = rpmsg_ctrldev_release,
 451         .unlocked_ioctl = rpmsg_ctrldev_ioctl,
 452         .compat_ioctl = compat_ptr_ioctl,
 453 };
 454
 455 static void rpmsg_ctrldev_release_device(struct device *dev)
 456 {
 457         struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
 458
 459         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 460         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 461         cdev_del(&ctrldev->cdev);
 462         kfree(ctrldev);
 463 }
 464
 465 static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
 466 {
 467         struct rpmsg_ctrldev *ctrldev;
 468         struct device *dev;
 469         int ret;
 470
 471         ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
 472         if (!ctrldev)
 473                 return -ENOMEM;
 474
 475         ctrldev->rpdev = rpdev;
 476
 477         dev = &ctrldev->dev;
 478         device_initialize(dev);
 479         dev->parent = &rpdev->dev;
 480         dev->class = rpmsg_class;
 481
 482         cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
 483         ctrldev->cdev.owner = THIS_MODULE;
 484
 485         ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
 486         if (ret < 0)
 487                 goto free_ctrldev;
 488         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
 489
 490         ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
 491         if (ret < 0)
 492                 goto free_minor_ida;
 493         dev->id = ret;
 494         dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
 495
 496         ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
 497         if (ret)
 498                 goto free_ctrl_ida;
 499
 500         /* We can now rely on the release function for cleanup */
 501         dev->release = rpmsg_ctrldev_release_device;
 502
 503         ret = device_add(dev);
 504         if (ret) {
 505                 dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
 506                 put_device(dev);
 507         }
 508
 509         dev_set_drvdata(&rpdev->dev, ctrldev);
 510
 511         return ret;
 512
 513 free_ctrl_ida:
 514         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 515 free_minor_ida:
 516         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 517 free_ctrldev:
 518         put_device(dev);
 519         kfree(ctrldev);
 520
 521         return ret;
 522 }
 523
 524 static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
 525 {
 526         struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
 527         int ret;
 528
 529         /* Destroy all endpoints */
 530         ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
 531         if (ret)
 532                 dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
 533
 534         device_del(&ctrldev->dev);
 535         put_device(&ctrldev->dev);
 536 }
 537
 538 static struct rpmsg_driver rpmsg_chrdev_driver = {
 539         .probe = rpmsg_chrdev_probe,
 540         .remove = rpmsg_chrdev_remove,
 541         .drv = {
 542                 .name = "rpmsg_chrdev",
 543         },
 544 };
 545
 546 static int rpmsg_char_init(void)
 547 {
 548         int ret;
 549
 550         ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
 551         if (ret < 0) {
 552                 pr_err("rpmsg: failed to allocate char dev region\n");
 553                 return ret;
 554         }
 555
 556         rpmsg_class = class_create(THIS_MODULE, "rpmsg");
 557         if (IS_ERR(rpmsg_class)) {
 558                 pr_err("failed to create rpmsg class\n");
 559                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 560                 return PTR_ERR(rpmsg_class);
 561         }
 562
 563         ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
 564         if (ret < 0) {
 565                 pr_err("rpmsgchr: failed to register rpmsg driver\n");
 566                 class_destroy(rpmsg_class);
 567                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 568         }
 569
 570         return ret;
 571 }
 572 postcore_initcall(rpmsg_char_init);
 573
 574 static void rpmsg_chrdev_exit(void)
 575 {
 576         unregister_rpmsg_driver(&rpmsg_chrdev_driver);
 577         class_destroy(rpmsg_class);
 578         unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 579 }
 580 module_exit(rpmsg_chrdev_exit);
 581
 582 MODULE_ALIAS("rpmsg:rpmsg_chrdev");
 583 MODULE_LICENSE("GPL v2");