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         cdev_device_del(&eptdev->cdev, &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         if (eptdev->ept)
 131                 return -EBUSY;
 132
 133         get_device(dev);
 134
 135         ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
 136         if (!ept) {
 137                 dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
 138                 put_device(dev);
 139                 return -EINVAL;
 140         }
 141
 142         eptdev->ept = ept;
 143         filp->private_data = eptdev;
 144
 145         return 0;
 146 }
 147
 148 static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
 149 {
 150         struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
 151         struct device *dev = &eptdev->dev;
 152
 153         /* Close the endpoint, if it's not already destroyed by the parent */
 154         mutex_lock(&eptdev->ept_lock);
 155         if (eptdev->ept) {
 156                 rpmsg_destroy_ept(eptdev->ept);
 157                 eptdev->ept = NULL;
 158         }
 159         mutex_unlock(&eptdev->ept_lock);
 160
 161         /* Discard all SKBs */
 162         skb_queue_purge(&eptdev->queue);
 163
 164         put_device(dev);
 165
 166         return 0;
 167 }
 168
 169 static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 170 {
 171         struct file *filp = iocb->ki_filp;
 172         struct rpmsg_eptdev *eptdev = filp->private_data;
 173         unsigned long flags;
 174         struct sk_buff *skb;
 175         int use;
 176
 177         if (!eptdev->ept)
 178                 return -EPIPE;
 179
 180         spin_lock_irqsave(&eptdev->queue_lock, flags);
 181
 182         /* Wait for data in the queue */
 183         if (skb_queue_empty(&eptdev->queue)) {
 184                 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
 185
 186                 if (filp->f_flags & O_NONBLOCK)
 187                         return -EAGAIN;
 188
 189                 /* Wait until we get data or the endpoint goes away */
 190                 if (wait_event_interruptible(eptdev->readq,
 191                                              !skb_queue_empty(&eptdev->queue) ||
 192                                              !eptdev->ept))
 193                         return -ERESTARTSYS;
 194
 195                 /* We lost the endpoint while waiting */
 196                 if (!eptdev->ept)
 197                         return -EPIPE;
 198
 199                 spin_lock_irqsave(&eptdev->queue_lock, flags);
 200         }
 201
 202         skb = skb_dequeue(&eptdev->queue);
 203         spin_unlock_irqrestore(&eptdev->queue_lock, flags);
 204         if (!skb)
 205                 return -EFAULT;
 206
 207         use = min_t(size_t, iov_iter_count(to), skb->len);
 208         if (copy_to_iter(skb->data, use, to) != use)
 209                 use = -EFAULT;
 210
 211         kfree_skb(skb);
 212
 213         return use;
 214 }
 215
 216 static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
 217                                        struct iov_iter *from)
 218 {
 219         struct file *filp = iocb->ki_filp;
 220         struct rpmsg_eptdev *eptdev = filp->private_data;
 221         size_t len = iov_iter_count(from);
 222         void *kbuf;
 223         int ret;
 224
 225         kbuf = kzalloc(len, GFP_KERNEL);
 226         if (!kbuf)
 227                 return -ENOMEM;
 228
 229         if (!copy_from_iter_full(kbuf, len, from)) {
 230                 ret = -EFAULT;
 231                 goto free_kbuf;
 232         }
 233
 234         if (mutex_lock_interruptible(&eptdev->ept_lock)) {
 235                 ret = -ERESTARTSYS;
 236                 goto free_kbuf;
 237         }
 238
 239         if (!eptdev->ept) {
 240                 ret = -EPIPE;
 241                 goto unlock_eptdev;
 242         }
 243
 244         if (filp->f_flags & O_NONBLOCK)
 245                 ret = rpmsg_trysendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
 246         else
 247                 ret = rpmsg_sendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
 248
 249 unlock_eptdev:
 250         mutex_unlock(&eptdev->ept_lock);
 251
 252 free_kbuf:
 253         kfree(kbuf);
 254         return ret < 0 ? ret : len;
 255 }
 256
 257 static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 258 {
 259         struct rpmsg_eptdev *eptdev = filp->private_data;
 260         __poll_t mask = 0;
 261
 262         if (!eptdev->ept)
 263                 return EPOLLERR;
 264
 265         poll_wait(filp, &eptdev->readq, wait);
 266
 267         if (!skb_queue_empty(&eptdev->queue))
 268                 mask |= EPOLLIN | EPOLLRDNORM;
 269
 270         mask |= rpmsg_poll(eptdev->ept, filp, wait);
 271
 272         return mask;
 273 }
 274
 275 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 276                                unsigned long arg)
 277 {
 278         struct rpmsg_eptdev *eptdev = fp->private_data;
 279
 280         if (cmd != RPMSG_DESTROY_EPT_IOCTL)
 281                 return -EINVAL;
 282
 283         return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
 284 }
 285
 286 static const struct file_operations rpmsg_eptdev_fops = {
 287         .owner = THIS_MODULE,
 288         .open = rpmsg_eptdev_open,
 289         .release = rpmsg_eptdev_release,
 290         .read_iter = rpmsg_eptdev_read_iter,
 291         .write_iter = rpmsg_eptdev_write_iter,
 292         .poll = rpmsg_eptdev_poll,
 293         .unlocked_ioctl = rpmsg_eptdev_ioctl,
 294         .compat_ioctl = compat_ptr_ioctl,
 295 };
 296
 297 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 298                          char *buf)
 299 {
 300         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 301
 302         return sprintf(buf, "%s\n", eptdev->chinfo.name);
 303 }
 304 static DEVICE_ATTR_RO(name);
 305
 306 static ssize_t src_show(struct device *dev, struct device_attribute *attr,
 307                          char *buf)
 308 {
 309         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 310
 311         return sprintf(buf, "%d\n", eptdev->chinfo.src);
 312 }
 313 static DEVICE_ATTR_RO(src);
 314
 315 static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
 316                          char *buf)
 317 {
 318         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 319
 320         return sprintf(buf, "%d\n", eptdev->chinfo.dst);
 321 }
 322 static DEVICE_ATTR_RO(dst);
 323
 324 static struct attribute *rpmsg_eptdev_attrs[] = {
 325         &dev_attr_name.attr,
 326         &dev_attr_src.attr,
 327         &dev_attr_dst.attr,
 328         NULL
 329 };
 330 ATTRIBUTE_GROUPS(rpmsg_eptdev);
 331
 332 static void rpmsg_eptdev_release_device(struct device *dev)
 333 {
 334         struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
 335
 336         ida_simple_remove(&rpmsg_ept_ida, dev->id);
 337         ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
 338         kfree(eptdev);
 339 }
 340
 341 static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
 342                                struct rpmsg_channel_info chinfo)
 343 {
 344         struct rpmsg_device *rpdev = ctrldev->rpdev;
 345         struct rpmsg_eptdev *eptdev;
 346         struct device *dev;
 347         int ret;
 348
 349         eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
 350         if (!eptdev)
 351                 return -ENOMEM;
 352
 353         dev = &eptdev->dev;
 354         eptdev->rpdev = rpdev;
 355         eptdev->chinfo = chinfo;
 356
 357         mutex_init(&eptdev->ept_lock);
 358         spin_lock_init(&eptdev->queue_lock);
 359         skb_queue_head_init(&eptdev->queue);
 360         init_waitqueue_head(&eptdev->readq);
 361
 362         device_initialize(dev);
 363         dev->class = rpmsg_class;
 364         dev->parent = &ctrldev->dev;
 365         dev->groups = rpmsg_eptdev_groups;
 366         dev_set_drvdata(dev, eptdev);
 367
 368         cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
 369         eptdev->cdev.owner = THIS_MODULE;
 370
 371         ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
 372         if (ret < 0)
 373                 goto free_eptdev;
 374         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
 375
 376         ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
 377         if (ret < 0)
 378                 goto free_minor_ida;
 379         dev->id = ret;
 380         dev_set_name(dev, "rpmsg%d", ret);
 381
 382         ret = cdev_device_add(&eptdev->cdev, &eptdev->dev);
 383         if (ret)
 384                 goto free_ept_ida;
 385
 386         /* We can now rely on the release function for cleanup */
 387         dev->release = rpmsg_eptdev_release_device;
 388
 389         return ret;
 390
 391 free_ept_ida:
 392         ida_simple_remove(&rpmsg_ept_ida, dev->id);
 393 free_minor_ida:
 394         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 395 free_eptdev:
 396         put_device(dev);
 397         kfree(eptdev);
 398
 399         return ret;
 400 }
 401
 402 static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
 403 {
 404         struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
 405
 406         get_device(&ctrldev->dev);
 407         filp->private_data = ctrldev;
 408
 409         return 0;
 410 }
 411
 412 static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
 413 {
 414         struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
 415
 416         put_device(&ctrldev->dev);
 417
 418         return 0;
 419 }
 420
 421 static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
 422                                 unsigned long arg)
 423 {
 424         struct rpmsg_ctrldev *ctrldev = fp->private_data;
 425         void __user *argp = (void __user *)arg;
 426         struct rpmsg_endpoint_info eptinfo;
 427         struct rpmsg_channel_info chinfo;
 428
 429         if (cmd != RPMSG_CREATE_EPT_IOCTL)
 430                 return -EINVAL;
 431
 432         if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
 433                 return -EFAULT;
 434
 435         memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
 436         chinfo.name[RPMSG_NAME_SIZE-1] = '\0';
 437         chinfo.src = eptinfo.src;
 438         chinfo.dst = eptinfo.dst;
 439
 440         return rpmsg_eptdev_create(ctrldev, chinfo);
 441 };
 442
 443 static const struct file_operations rpmsg_ctrldev_fops = {
 444         .owner = THIS_MODULE,
 445         .open = rpmsg_ctrldev_open,
 446         .release = rpmsg_ctrldev_release,
 447         .unlocked_ioctl = rpmsg_ctrldev_ioctl,
 448         .compat_ioctl = compat_ptr_ioctl,
 449 };
 450
 451 static void rpmsg_ctrldev_release_device(struct device *dev)
 452 {
 453         struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
 454
 455         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 456         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 457         kfree(ctrldev);
 458 }
 459
 460 static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
 461 {
 462         struct rpmsg_ctrldev *ctrldev;
 463         struct device *dev;
 464         int ret;
 465
 466         ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
 467         if (!ctrldev)
 468                 return -ENOMEM;
 469
 470         ctrldev->rpdev = rpdev;
 471
 472         dev = &ctrldev->dev;
 473         device_initialize(dev);
 474         dev->parent = &rpdev->dev;
 475         dev->class = rpmsg_class;
 476
 477         cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
 478         ctrldev->cdev.owner = THIS_MODULE;
 479
 480         ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
 481         if (ret < 0)
 482                 goto free_ctrldev;
 483         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
 484
 485         ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
 486         if (ret < 0)
 487                 goto free_minor_ida;
 488         dev->id = ret;
 489         dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
 490
 491         ret = cdev_device_add(&ctrldev->cdev, &ctrldev->dev);
 492         if (ret)
 493                 goto free_ctrl_ida;
 494
 495         /* We can now rely on the release function for cleanup */
 496         dev->release = rpmsg_ctrldev_release_device;
 497
 498         dev_set_drvdata(&rpdev->dev, ctrldev);
 499
 500         return ret;
 501
 502 free_ctrl_ida:
 503         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 504 free_minor_ida:
 505         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 506 free_ctrldev:
 507         put_device(dev);
 508         kfree(ctrldev);
 509
 510         return ret;
 511 }
 512
 513 static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
 514 {
 515         struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
 516         int ret;
 517
 518         /* Destroy all endpoints */
 519         ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
 520         if (ret)
 521                 dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
 522
 523         cdev_device_del(&ctrldev->cdev, &ctrldev->dev);
 524         put_device(&ctrldev->dev);
 525 }
 526
 527 static struct rpmsg_driver rpmsg_chrdev_driver = {
 528         .probe = rpmsg_chrdev_probe,
 529         .remove = rpmsg_chrdev_remove,
 530         .drv = {
 531                 .name = "rpmsg_chrdev",
 532         },
 533 };
 534
 535 static int rpmsg_chrdev_init(void)
 536 {
 537         int ret;
 538
 539         ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
 540         if (ret < 0) {
 541                 pr_err("rpmsg: failed to allocate char dev region\n");
 542                 return ret;
 543         }
 544
 545         rpmsg_class = class_create(THIS_MODULE, "rpmsg");
 546         if (IS_ERR(rpmsg_class)) {
 547                 pr_err("failed to create rpmsg class\n");
 548                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 549                 return PTR_ERR(rpmsg_class);
 550         }
 551
 552         ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
 553         if (ret < 0) {
 554                 pr_err("rpmsgchr: failed to register rpmsg driver\n");
 555                 class_destroy(rpmsg_class);
 556                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 557         }
 558
 559         return ret;
 560 }
 561 postcore_initcall(rpmsg_chrdev_init);
 562
 563 static void rpmsg_chrdev_exit(void)
 564 {
 565         unregister_rpmsg_driver(&rpmsg_chrdev_driver);
 566         class_destroy(rpmsg_class);
 567         unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 568 }
 569 module_exit(rpmsg_chrdev_exit);
 570
 571 MODULE_ALIAS("rpmsg:rpmsg_chrdev");
 572 MODULE_LICENSE("GPL v2");