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                 return -EFAULT;
 232
 233         if (mutex_lock_interruptible(&eptdev->ept_lock)) {
 234                 ret = -ERESTARTSYS;
 235                 goto free_kbuf;
 236         }
 237
 238         if (!eptdev->ept) {
 239                 ret = -EPIPE;
 240                 goto unlock_eptdev;
 241         }
 242
 243         if (filp->f_flags & O_NONBLOCK)
 244                 ret = rpmsg_trysend(eptdev->ept, kbuf, len);
 245         else
 246                 ret = rpmsg_send(eptdev->ept, kbuf, len);
 247
 248 unlock_eptdev:
 249         mutex_unlock(&eptdev->ept_lock);
 250
 251 free_kbuf:
 252         kfree(kbuf);
 253         return ret < 0 ? ret : len;
 254 }
 255
 256 static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 257 {
 258         struct rpmsg_eptdev *eptdev = filp->private_data;
 259         __poll_t mask = 0;
 260
 261         if (!eptdev->ept)
 262                 return EPOLLERR;
 263
 264         poll_wait(filp, &eptdev->readq, wait);
 265
 266         if (!skb_queue_empty(&eptdev->queue))
 267                 mask |= EPOLLIN | EPOLLRDNORM;
 268
 269         mask |= rpmsg_poll(eptdev->ept, filp, wait);
 270
 271         return mask;
 272 }
 273
 274 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 275                                unsigned long arg)
 276 {
 277         struct rpmsg_eptdev *eptdev = fp->private_data;
 278
 279         if (cmd != RPMSG_DESTROY_EPT_IOCTL)
 280                 return -EINVAL;
 281
 282         return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
 283 }
 284
 285 static const struct file_operations rpmsg_eptdev_fops = {
 286         .owner = THIS_MODULE,
 287         .open = rpmsg_eptdev_open,
 288         .release = rpmsg_eptdev_release,
 289         .read_iter = rpmsg_eptdev_read_iter,
 290         .write_iter = rpmsg_eptdev_write_iter,
 291         .poll = rpmsg_eptdev_poll,
 292         .unlocked_ioctl = rpmsg_eptdev_ioctl,
 293         .compat_ioctl = rpmsg_eptdev_ioctl,
 294 };
 295
 296 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 297                          char *buf)
 298 {
 299         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 300
 301         return sprintf(buf, "%s\n", eptdev->chinfo.name);
 302 }
 303 static DEVICE_ATTR_RO(name);
 304
 305 static ssize_t src_show(struct device *dev, struct device_attribute *attr,
 306                          char *buf)
 307 {
 308         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 309
 310         return sprintf(buf, "%d\n", eptdev->chinfo.src);
 311 }
 312 static DEVICE_ATTR_RO(src);
 313
 314 static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
 315                          char *buf)
 316 {
 317         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 318
 319         return sprintf(buf, "%d\n", eptdev->chinfo.dst);
 320 }
 321 static DEVICE_ATTR_RO(dst);
 322
 323 static struct attribute *rpmsg_eptdev_attrs[] = {
 324         &dev_attr_name.attr,
 325         &dev_attr_src.attr,
 326         &dev_attr_dst.attr,
 327         NULL
 328 };
 329 ATTRIBUTE_GROUPS(rpmsg_eptdev);
 330
 331 static void rpmsg_eptdev_release_device(struct device *dev)
 332 {
 333         struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
 334
 335         ida_simple_remove(&rpmsg_ept_ida, dev->id);
 336         ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
 337         cdev_del(&eptdev->cdev);
 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_add(&eptdev->cdev, dev->devt, 1);
 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         ret = device_add(dev);
 390         if (ret) {
 391                 dev_err(dev, "device_add failed: %d\n", ret);
 392                 put_device(dev);
 393         }
 394
 395         return ret;
 396
 397 free_ept_ida:
 398         ida_simple_remove(&rpmsg_ept_ida, dev->id);
 399 free_minor_ida:
 400         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 401 free_eptdev:
 402         put_device(dev);
 403         kfree(eptdev);
 404
 405         return ret;
 406 }
 407
 408 static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
 409 {
 410         struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
 411
 412         get_device(&ctrldev->dev);
 413         filp->private_data = ctrldev;
 414
 415         return 0;
 416 }
 417
 418 static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
 419 {
 420         struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
 421
 422         put_device(&ctrldev->dev);
 423
 424         return 0;
 425 }
 426
 427 static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
 428                                 unsigned long arg)
 429 {
 430         struct rpmsg_ctrldev *ctrldev = fp->private_data;
 431         void __user *argp = (void __user *)arg;
 432         struct rpmsg_endpoint_info eptinfo;
 433         struct rpmsg_channel_info chinfo;
 434
 435         if (cmd != RPMSG_CREATE_EPT_IOCTL)
 436                 return -EINVAL;
 437
 438         if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
 439                 return -EFAULT;
 440
 441         memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
 442         chinfo.name[RPMSG_NAME_SIZE-1] = '\0';
 443         chinfo.src = eptinfo.src;
 444         chinfo.dst = eptinfo.dst;
 445
 446         return rpmsg_eptdev_create(ctrldev, chinfo);
 447 };
 448
 449 static const struct file_operations rpmsg_ctrldev_fops = {
 450         .owner = THIS_MODULE,
 451         .open = rpmsg_ctrldev_open,
 452         .release = rpmsg_ctrldev_release,
 453         .unlocked_ioctl = rpmsg_ctrldev_ioctl,
 454         .compat_ioctl = rpmsg_ctrldev_ioctl,
 455 };
 456
 457 static void rpmsg_ctrldev_release_device(struct device *dev)
 458 {
 459         struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
 460
 461         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 462         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 463         cdev_del(&ctrldev->cdev);
 464         kfree(ctrldev);
 465 }
 466
 467 static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
 468 {
 469         struct rpmsg_ctrldev *ctrldev;
 470         struct device *dev;
 471         int ret;
 472
 473         ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
 474         if (!ctrldev)
 475                 return -ENOMEM;
 476
 477         ctrldev->rpdev = rpdev;
 478
 479         dev = &ctrldev->dev;
 480         device_initialize(dev);
 481         dev->parent = &rpdev->dev;
 482         dev->class = rpmsg_class;
 483
 484         cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
 485         ctrldev->cdev.owner = THIS_MODULE;
 486
 487         ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
 488         if (ret < 0)
 489                 goto free_ctrldev;
 490         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
 491
 492         ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
 493         if (ret < 0)
 494                 goto free_minor_ida;
 495         dev->id = ret;
 496         dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
 497
 498         ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
 499         if (ret)
 500                 goto free_ctrl_ida;
 501
 502         /* We can now rely on the release function for cleanup */
 503         dev->release = rpmsg_ctrldev_release_device;
 504
 505         ret = device_add(dev);
 506         if (ret) {
 507                 dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
 508                 put_device(dev);
 509         }
 510
 511         dev_set_drvdata(&rpdev->dev, ctrldev);
 512
 513         return ret;
 514
 515 free_ctrl_ida:
 516         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 517 free_minor_ida:
 518         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 519 free_ctrldev:
 520         put_device(dev);
 521         kfree(ctrldev);
 522
 523         return ret;
 524 }
 525
 526 static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
 527 {
 528         struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
 529         int ret;
 530
 531         /* Destroy all endpoints */
 532         ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
 533         if (ret)
 534                 dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
 535
 536         device_del(&ctrldev->dev);
 537         put_device(&ctrldev->dev);
 538 }
 539
 540 static struct rpmsg_driver rpmsg_chrdev_driver = {
 541         .probe = rpmsg_chrdev_probe,
 542         .remove = rpmsg_chrdev_remove,
 543         .drv = {
 544                 .name = "rpmsg_chrdev",
 545         },
 546 };
 547
 548 static int rpmsg_char_init(void)
 549 {
 550         int ret;
 551
 552         ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
 553         if (ret < 0) {
 554                 pr_err("rpmsg: failed to allocate char dev region\n");
 555                 return ret;
 556         }
 557
 558         rpmsg_class = class_create(THIS_MODULE, "rpmsg");
 559         if (IS_ERR(rpmsg_class)) {
 560                 pr_err("failed to create rpmsg class\n");
 561                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 562                 return PTR_ERR(rpmsg_class);
 563         }
 564
 565         ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
 566         if (ret < 0) {
 567                 pr_err("rpmsgchr: failed to register rpmsg driver\n");
 568                 class_destroy(rpmsg_class);
 569                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 570         }
 571
 572         return ret;
 573 }
 574 postcore_initcall(rpmsg_char_init);
 575
 576 static void rpmsg_chrdev_exit(void)
 577 {
 578         unregister_rpmsg_driver(&rpmsg_chrdev_driver);
 579         class_destroy(rpmsg_class);
 580         unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 581 }
 582 module_exit(rpmsg_chrdev_exit);
 583
 584 MODULE_ALIAS("rpmsg:rpmsg_chrdev");
 585 MODULE_LICENSE("GPL v2");