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         struct sk_buff *skb;
 150
 151         /* Close the endpoint, if it's not already destroyed by the parent */
 152         mutex_lock(&eptdev->ept_lock);
 153         if (eptdev->ept) {
 154                 rpmsg_destroy_ept(eptdev->ept);
 155                 eptdev->ept = NULL;
 156         }
 157         mutex_unlock(&eptdev->ept_lock);
 158
 159         /* Discard all SKBs */
 160         while (!skb_queue_empty(&eptdev->queue)) {
 161                 skb = skb_dequeue(&eptdev->queue);
 162                 kfree_skb(skb);
 163         }
 164
 165         put_device(dev);
 166
 167         return 0;
 168 }
 169
 170 static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 171 {
 172         struct file *filp = iocb->ki_filp;
 173         struct rpmsg_eptdev *eptdev = filp->private_data;
 174         unsigned long flags;
 175         struct sk_buff *skb;
 176         int use;
 177
 178         if (!eptdev->ept)
 179                 return -EPIPE;
 180
 181         spin_lock_irqsave(&eptdev->queue_lock, flags);
 182
 183         /* Wait for data in the queue */
 184         if (skb_queue_empty(&eptdev->queue)) {
 185                 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
 186
 187                 if (filp->f_flags & O_NONBLOCK)
 188                         return -EAGAIN;
 189
 190                 /* Wait until we get data or the endpoint goes away */
 191                 if (wait_event_interruptible(eptdev->readq,
 192                                              !skb_queue_empty(&eptdev->queue) ||
 193                                              !eptdev->ept))
 194                         return -ERESTARTSYS;
 195
 196                 /* We lost the endpoint while waiting */
 197                 if (!eptdev->ept)
 198                         return -EPIPE;
 199
 200                 spin_lock_irqsave(&eptdev->queue_lock, flags);
 201         }
 202
 203         skb = skb_dequeue(&eptdev->queue);
 204         spin_unlock_irqrestore(&eptdev->queue_lock, flags);
 205         if (!skb)
 206                 return -EFAULT;
 207
 208         use = min_t(size_t, iov_iter_count(to), skb->len);
 209         if (copy_to_iter(skb->data, use, to) != use)
 210                 use = -EFAULT;
 211
 212         kfree_skb(skb);
 213
 214         return use;
 215 }
 216
 217 static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
 218                                        struct iov_iter *from)
 219 {
 220         struct file *filp = iocb->ki_filp;
 221         struct rpmsg_eptdev *eptdev = filp->private_data;
 222         size_t len = iov_iter_count(from);
 223         void *kbuf;
 224         int ret;
 225
 226         kbuf = kzalloc(len, GFP_KERNEL);
 227         if (!kbuf)
 228                 return -ENOMEM;
 229
 230         if (!copy_from_iter_full(kbuf, len, from)) {
 231                 ret = -EFAULT;
 232                 goto free_kbuf;
 233         }
 234
 235         if (mutex_lock_interruptible(&eptdev->ept_lock)) {
 236                 ret = -ERESTARTSYS;
 237                 goto free_kbuf;
 238         }
 239
 240         if (!eptdev->ept) {
 241                 ret = -EPIPE;
 242                 goto unlock_eptdev;
 243         }
 244
 245         if (filp->f_flags & O_NONBLOCK)
 246                 ret = rpmsg_trysend(eptdev->ept, kbuf, len);
 247         else
 248                 ret = rpmsg_send(eptdev->ept, kbuf, len);
 249
 250 unlock_eptdev:
 251         mutex_unlock(&eptdev->ept_lock);
 252
 253 free_kbuf:
 254         kfree(kbuf);
 255         return ret < 0 ? ret : len;
 256 }
 257
 258 static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 259 {
 260         struct rpmsg_eptdev *eptdev = filp->private_data;
 261         __poll_t mask = 0;
 262
 263         if (!eptdev->ept)
 264                 return EPOLLERR;
 265
 266         poll_wait(filp, &eptdev->readq, wait);
 267
 268         if (!skb_queue_empty(&eptdev->queue))
 269                 mask |= EPOLLIN | EPOLLRDNORM;
 270
 271         mask |= rpmsg_poll(eptdev->ept, filp, wait);
 272
 273         return mask;
 274 }
 275
 276 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 277                                unsigned long arg)
 278 {
 279         struct rpmsg_eptdev *eptdev = fp->private_data;
 280
 281         if (cmd != RPMSG_DESTROY_EPT_IOCTL)
 282                 return -EINVAL;
 283
 284         return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
 285 }
 286
 287 static const struct file_operations rpmsg_eptdev_fops = {
 288         .owner = THIS_MODULE,
 289         .open = rpmsg_eptdev_open,
 290         .release = rpmsg_eptdev_release,
 291         .read_iter = rpmsg_eptdev_read_iter,
 292         .write_iter = rpmsg_eptdev_write_iter,
 293         .poll = rpmsg_eptdev_poll,
 294         .unlocked_ioctl = rpmsg_eptdev_ioctl,
 295         .compat_ioctl = rpmsg_eptdev_ioctl,
 296 };
 297
 298 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 299                          char *buf)
 300 {
 301         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 302
 303         return sprintf(buf, "%s\n", eptdev->chinfo.name);
 304 }
 305 static DEVICE_ATTR_RO(name);
 306
 307 static ssize_t src_show(struct device *dev, struct device_attribute *attr,
 308                          char *buf)
 309 {
 310         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 311
 312         return sprintf(buf, "%d\n", eptdev->chinfo.src);
 313 }
 314 static DEVICE_ATTR_RO(src);
 315
 316 static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
 317                          char *buf)
 318 {
 319         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 320
 321         return sprintf(buf, "%d\n", eptdev->chinfo.dst);
 322 }
 323 static DEVICE_ATTR_RO(dst);
 324
 325 static struct attribute *rpmsg_eptdev_attrs[] = {
 326         &dev_attr_name.attr,
 327         &dev_attr_src.attr,
 328         &dev_attr_dst.attr,
 329         NULL
 330 };
 331 ATTRIBUTE_GROUPS(rpmsg_eptdev);
 332
 333 static void rpmsg_eptdev_release_device(struct device *dev)
 334 {
 335         struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
 336
 337         ida_simple_remove(&rpmsg_ept_ida, dev->id);
 338         ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
 339         cdev_del(&eptdev->cdev);
 340         kfree(eptdev);
 341 }
 342
 343 static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
 344                                struct rpmsg_channel_info chinfo)
 345 {
 346         struct rpmsg_device *rpdev = ctrldev->rpdev;
 347         struct rpmsg_eptdev *eptdev;
 348         struct device *dev;
 349         int ret;
 350
 351         eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
 352         if (!eptdev)
 353                 return -ENOMEM;
 354
 355         dev = &eptdev->dev;
 356         eptdev->rpdev = rpdev;
 357         eptdev->chinfo = chinfo;
 358
 359         mutex_init(&eptdev->ept_lock);
 360         spin_lock_init(&eptdev->queue_lock);
 361         skb_queue_head_init(&eptdev->queue);
 362         init_waitqueue_head(&eptdev->readq);
 363
 364         device_initialize(dev);
 365         dev->class = rpmsg_class;
 366         dev->parent = &ctrldev->dev;
 367         dev->groups = rpmsg_eptdev_groups;
 368         dev_set_drvdata(dev, eptdev);
 369
 370         cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
 371         eptdev->cdev.owner = THIS_MODULE;
 372
 373         ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
 374         if (ret < 0)
 375                 goto free_eptdev;
 376         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
 377
 378         ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
 379         if (ret < 0)
 380                 goto free_minor_ida;
 381         dev->id = ret;
 382         dev_set_name(dev, "rpmsg%d", ret);
 383
 384         ret = cdev_add(&eptdev->cdev, dev->devt, 1);
 385         if (ret)
 386                 goto free_ept_ida;
 387
 388         /* We can now rely on the release function for cleanup */
 389         dev->release = rpmsg_eptdev_release_device;
 390
 391         ret = device_add(dev);
 392         if (ret) {
 393                 dev_err(dev, "device_add failed: %d\n", ret);
 394                 put_device(dev);
 395         }
 396
 397         return ret;
 398
 399 free_ept_ida:
 400         ida_simple_remove(&rpmsg_ept_ida, dev->id);
 401 free_minor_ida:
 402         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 403 free_eptdev:
 404         put_device(dev);
 405         kfree(eptdev);
 406
 407         return ret;
 408 }
 409
 410 static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
 411 {
 412         struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
 413
 414         get_device(&ctrldev->dev);
 415         filp->private_data = ctrldev;
 416
 417         return 0;
 418 }
 419
 420 static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
 421 {
 422         struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
 423
 424         put_device(&ctrldev->dev);
 425
 426         return 0;
 427 }
 428
 429 static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
 430                                 unsigned long arg)
 431 {
 432         struct rpmsg_ctrldev *ctrldev = fp->private_data;
 433         void __user *argp = (void __user *)arg;
 434         struct rpmsg_endpoint_info eptinfo;
 435         struct rpmsg_channel_info chinfo;
 436
 437         if (cmd != RPMSG_CREATE_EPT_IOCTL)
 438                 return -EINVAL;
 439
 440         if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
 441                 return -EFAULT;
 442
 443         memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
 444         chinfo.name[RPMSG_NAME_SIZE-1] = '\0';
 445         chinfo.src = eptinfo.src;
 446         chinfo.dst = eptinfo.dst;
 447
 448         return rpmsg_eptdev_create(ctrldev, chinfo);
 449 };
 450
 451 static const struct file_operations rpmsg_ctrldev_fops = {
 452         .owner = THIS_MODULE,
 453         .open = rpmsg_ctrldev_open,
 454         .release = rpmsg_ctrldev_release,
 455         .unlocked_ioctl = rpmsg_ctrldev_ioctl,
 456         .compat_ioctl = rpmsg_ctrldev_ioctl,
 457 };
 458
 459 static void rpmsg_ctrldev_release_device(struct device *dev)
 460 {
 461         struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
 462
 463         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 464         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 465         cdev_del(&ctrldev->cdev);
 466         kfree(ctrldev);
 467 }
 468
 469 static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
 470 {
 471         struct rpmsg_ctrldev *ctrldev;
 472         struct device *dev;
 473         int ret;
 474
 475         ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
 476         if (!ctrldev)
 477                 return -ENOMEM;
 478
 479         ctrldev->rpdev = rpdev;
 480
 481         dev = &ctrldev->dev;
 482         device_initialize(dev);
 483         dev->parent = &rpdev->dev;
 484         dev->class = rpmsg_class;
 485
 486         cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
 487         ctrldev->cdev.owner = THIS_MODULE;
 488
 489         ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
 490         if (ret < 0)
 491                 goto free_ctrldev;
 492         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
 493
 494         ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
 495         if (ret < 0)
 496                 goto free_minor_ida;
 497         dev->id = ret;
 498         dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
 499
 500         ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
 501         if (ret)
 502                 goto free_ctrl_ida;
 503
 504         /* We can now rely on the release function for cleanup */
 505         dev->release = rpmsg_ctrldev_release_device;
 506
 507         ret = device_add(dev);
 508         if (ret) {
 509                 dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
 510                 put_device(dev);
 511         }
 512
 513         dev_set_drvdata(&rpdev->dev, ctrldev);
 514
 515         return ret;
 516
 517 free_ctrl_ida:
 518         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 519 free_minor_ida:
 520         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 521 free_ctrldev:
 522         put_device(dev);
 523         kfree(ctrldev);
 524
 525         return ret;
 526 }
 527
 528 static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
 529 {
 530         struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
 531         int ret;
 532
 533         /* Destroy all endpoints */
 534         ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
 535         if (ret)
 536                 dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
 537
 538         device_del(&ctrldev->dev);
 539         put_device(&ctrldev->dev);
 540 }
 541
 542 static struct rpmsg_driver rpmsg_chrdev_driver = {
 543         .probe = rpmsg_chrdev_probe,
 544         .remove = rpmsg_chrdev_remove,
 545         .drv = {
 546                 .name = "rpmsg_chrdev",
 547         },
 548 };
 549
 550 static int rpmsg_char_init(void)
 551 {
 552         int ret;
 553
 554         ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
 555         if (ret < 0) {
 556                 pr_err("rpmsg: failed to allocate char dev region\n");
 557                 return ret;
 558         }
 559
 560         rpmsg_class = class_create(THIS_MODULE, "rpmsg");
 561         if (IS_ERR(rpmsg_class)) {
 562                 pr_err("failed to create rpmsg class\n");
 563                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 564                 return PTR_ERR(rpmsg_class);
 565         }
 566
 567         ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
 568         if (ret < 0) {
 569                 pr_err("rpmsgchr: failed to register rpmsg driver\n");
 570                 class_destroy(rpmsg_class);
 571                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 572         }
 573
 574         return ret;
 575 }
 576 postcore_initcall(rpmsg_char_init);
 577
 578 static void rpmsg_chrdev_exit(void)
 579 {
 580         unregister_rpmsg_driver(&rpmsg_chrdev_driver);
 581         class_destroy(rpmsg_class);
 582         unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 583 }
 584 module_exit(rpmsg_chrdev_exit);
 585
 586 MODULE_ALIAS("rpmsg:rpmsg_chrdev");
 587 MODULE_LICENSE("GPL v2");