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(struct file *filp, char __user *buf,
 171                                  size_t len, loff_t *f_pos)
 172 {
 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, len, skb->len);
 209         if (copy_to_user(buf, skb->data, use))
 210                 use = -EFAULT;
 211
 212         kfree_skb(skb);
 213
 214         return use;
 215 }
 216
 217 static ssize_t rpmsg_eptdev_write(struct file *filp, const char __user *buf,
 218                                   size_t len, loff_t *f_pos)
 219 {
 220         struct rpmsg_eptdev *eptdev = filp->private_data;
 221         void *kbuf;
 222         int ret;
 223
 224         kbuf = memdup_user(buf, len);
 225         if (IS_ERR(kbuf))
 226                 return PTR_ERR(kbuf);
 227
 228         if (mutex_lock_interruptible(&eptdev->ept_lock)) {
 229                 ret = -ERESTARTSYS;
 230                 goto free_kbuf;
 231         }
 232
 233         if (!eptdev->ept) {
 234                 ret = -EPIPE;
 235                 goto unlock_eptdev;
 236         }
 237
 238         if (filp->f_flags & O_NONBLOCK)
 239                 ret = rpmsg_trysend(eptdev->ept, kbuf, len);
 240         else
 241                 ret = rpmsg_send(eptdev->ept, kbuf, len);
 242
 243 unlock_eptdev:
 244         mutex_unlock(&eptdev->ept_lock);
 245
 246 free_kbuf:
 247         kfree(kbuf);
 248         return ret < 0 ? ret : len;
 249 }
 250
 251 static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 252 {
 253         struct rpmsg_eptdev *eptdev = filp->private_data;
 254         __poll_t mask = 0;
 255
 256         if (!eptdev->ept)
 257                 return EPOLLERR;
 258
 259         poll_wait(filp, &eptdev->readq, wait);
 260
 261         if (!skb_queue_empty(&eptdev->queue))
 262                 mask |= EPOLLIN | EPOLLRDNORM;
 263
 264         mask |= rpmsg_poll(eptdev->ept, filp, wait);
 265
 266         return mask;
 267 }
 268
 269 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 270                                unsigned long arg)
 271 {
 272         struct rpmsg_eptdev *eptdev = fp->private_data;
 273
 274         if (cmd != RPMSG_DESTROY_EPT_IOCTL)
 275                 return -EINVAL;
 276
 277         return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
 278 }
 279
 280 static const struct file_operations rpmsg_eptdev_fops = {
 281         .owner = THIS_MODULE,
 282         .open = rpmsg_eptdev_open,
 283         .release = rpmsg_eptdev_release,
 284         .read = rpmsg_eptdev_read,
 285         .write = rpmsg_eptdev_write,
 286         .poll = rpmsg_eptdev_poll,
 287         .unlocked_ioctl = rpmsg_eptdev_ioctl,
 288 };
 289
 290 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 291                          char *buf)
 292 {
 293         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 294
 295         return sprintf(buf, "%s\n", eptdev->chinfo.name);
 296 }
 297 static DEVICE_ATTR_RO(name);
 298
 299 static ssize_t src_show(struct device *dev, struct device_attribute *attr,
 300                          char *buf)
 301 {
 302         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 303
 304         return sprintf(buf, "%d\n", eptdev->chinfo.src);
 305 }
 306 static DEVICE_ATTR_RO(src);
 307
 308 static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
 309                          char *buf)
 310 {
 311         struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
 312
 313         return sprintf(buf, "%d\n", eptdev->chinfo.dst);
 314 }
 315 static DEVICE_ATTR_RO(dst);
 316
 317 static struct attribute *rpmsg_eptdev_attrs[] = {
 318         &dev_attr_name.attr,
 319         &dev_attr_src.attr,
 320         &dev_attr_dst.attr,
 321         NULL
 322 };
 323 ATTRIBUTE_GROUPS(rpmsg_eptdev);
 324
 325 static void rpmsg_eptdev_release_device(struct device *dev)
 326 {
 327         struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
 328
 329         ida_simple_remove(&rpmsg_ept_ida, dev->id);
 330         ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
 331         cdev_del(&eptdev->cdev);
 332         kfree(eptdev);
 333 }
 334
 335 static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
 336                                struct rpmsg_channel_info chinfo)
 337 {
 338         struct rpmsg_device *rpdev = ctrldev->rpdev;
 339         struct rpmsg_eptdev *eptdev;
 340         struct device *dev;
 341         int ret;
 342
 343         eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
 344         if (!eptdev)
 345                 return -ENOMEM;
 346
 347         dev = &eptdev->dev;
 348         eptdev->rpdev = rpdev;
 349         eptdev->chinfo = chinfo;
 350
 351         mutex_init(&eptdev->ept_lock);
 352         spin_lock_init(&eptdev->queue_lock);
 353         skb_queue_head_init(&eptdev->queue);
 354         init_waitqueue_head(&eptdev->readq);
 355
 356         device_initialize(dev);
 357         dev->class = rpmsg_class;
 358         dev->parent = &ctrldev->dev;
 359         dev->groups = rpmsg_eptdev_groups;
 360         dev_set_drvdata(dev, eptdev);
 361
 362         cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
 363         eptdev->cdev.owner = THIS_MODULE;
 364
 365         ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
 366         if (ret < 0)
 367                 goto free_eptdev;
 368         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
 369
 370         ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
 371         if (ret < 0)
 372                 goto free_minor_ida;
 373         dev->id = ret;
 374         dev_set_name(dev, "rpmsg%d", ret);
 375
 376         ret = cdev_add(&eptdev->cdev, dev->devt, 1);
 377         if (ret)
 378                 goto free_ept_ida;
 379
 380         /* We can now rely on the release function for cleanup */
 381         dev->release = rpmsg_eptdev_release_device;
 382
 383         ret = device_add(dev);
 384         if (ret) {
 385                 dev_err(dev, "device_add failed: %d\n", ret);
 386                 put_device(dev);
 387         }
 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 };
 449
 450 static void rpmsg_ctrldev_release_device(struct device *dev)
 451 {
 452         struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
 453
 454         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 455         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 456         cdev_del(&ctrldev->cdev);
 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_add(&ctrldev->cdev, dev->devt, 1);
 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         ret = device_add(dev);
 499         if (ret) {
 500                 dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
 501                 put_device(dev);
 502         }
 503
 504         dev_set_drvdata(&rpdev->dev, ctrldev);
 505
 506         return ret;
 507
 508 free_ctrl_ida:
 509         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 510 free_minor_ida:
 511         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 512 free_ctrldev:
 513         put_device(dev);
 514         kfree(ctrldev);
 515
 516         return ret;
 517 }
 518
 519 static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
 520 {
 521         struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
 522         int ret;
 523
 524         /* Destroy all endpoints */
 525         ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
 526         if (ret)
 527                 dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
 528
 529         device_del(&ctrldev->dev);
 530         put_device(&ctrldev->dev);
 531 }
 532
 533 static struct rpmsg_driver rpmsg_chrdev_driver = {
 534         .probe = rpmsg_chrdev_probe,
 535         .remove = rpmsg_chrdev_remove,
 536         .drv = {
 537                 .name = "rpmsg_chrdev",
 538         },
 539 };
 540
 541 static int rpmsg_char_init(void)
 542 {
 543         int ret;
 544
 545         ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
 546         if (ret < 0) {
 547                 pr_err("rpmsg: failed to allocate char dev region\n");
 548                 return ret;
 549         }
 550
 551         rpmsg_class = class_create(THIS_MODULE, "rpmsg");
 552         if (IS_ERR(rpmsg_class)) {
 553                 pr_err("failed to create rpmsg class\n");
 554                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 555                 return PTR_ERR(rpmsg_class);
 556         }
 557
 558         ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
 559         if (ret < 0) {
 560                 pr_err("rpmsgchr: failed to register rpmsg driver\n");
 561                 class_destroy(rpmsg_class);
 562                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 563         }
 564
 565         return ret;
 566 }
 567 postcore_initcall(rpmsg_char_init);
 568
 569 static void rpmsg_chrdev_exit(void)
 570 {
 571         unregister_rpmsg_driver(&rpmsg_chrdev_driver);
 572         class_destroy(rpmsg_class);
 573         unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 574 }
 575 module_exit(rpmsg_chrdev_exit);
 576
 577 MODULE_ALIAS("rpmsg:rpmsg_chrdev");
 578 MODULE_LICENSE("GPL v2");