drivers/rpmsg/rpmsg_char.c

   1 /*
   2  * Copyright (c) 2016, Linaro Ltd.
   3  * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
   4  * Copyright (c) 2012, PetaLogix
   5  * Copyright (c) 2011, Texas Instruments, Inc.
   6  * Copyright (c) 2011, Google, Inc.
   7  *
   8  * Based on rpmsg performance statistics driver by Michal Simek, which in turn
   9  * was based on TI & Google OMX rpmsg driver.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 and
  13  * only version 2 as published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  */
  20 #include <linux/cdev.h>
  21 #include <linux/device.h>
  22 #include <linux/fs.h>
  23 #include <linux/idr.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/poll.h>
  27 #include <linux/rpmsg.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/slab.h>
  30 #include <linux/uaccess.h>
  31 #include <uapi/linux/rpmsg.h>
  32
  33 #include "rpmsg_internal.h"
  34
  35 #define RPMSG_DEV_MAX   (MINORMASK + 1)
  36
  37 static dev_t rpmsg_major;
  38 static struct class *rpmsg_class;
  39
  40 static DEFINE_IDA(rpmsg_ctrl_ida);
  41 static DEFINE_IDA(rpmsg_ept_ida);
  42 static DEFINE_IDA(rpmsg_minor_ida);
  43
  44 #define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
  45 #define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)
  46
  47 #define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
  48 #define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
  49
  50 /**
  51  * struct rpmsg_ctrldev - control device for instantiating endpoint devices
  52  * @rpdev:      underlaying rpmsg device
  53  * @cdev:       cdev for the ctrl device
  54  * @dev:        device for the ctrl device
  55  */
  56 struct rpmsg_ctrldev {
  57         struct rpmsg_device *rpdev;
  58         struct cdev cdev;
  59         struct device dev;
  60 };
  61
  62 /**
  63  * struct rpmsg_eptdev - endpoint device context
  64  * @dev:        endpoint device
  65  * @cdev:       cdev for the endpoint device
  66  * @rpdev:      underlaying rpmsg device
  67  * @chinfo:     info used to open the endpoint
  68  * @ept_lock:   synchronization of @ept modifications
  69  * @ept:        rpmsg endpoint reference, when open
  70  * @queue_lock: synchronization of @queue operations
  71  * @queue:      incoming message queue
  72  * @readq:      wait object for incoming queue
  73  */
  74 struct rpmsg_eptdev {
  75         struct device dev;
  76         struct cdev cdev;
  77
  78         struct rpmsg_device *rpdev;
  79         struct rpmsg_channel_info chinfo;
  80
  81         struct mutex ept_lock;
  82         struct rpmsg_endpoint *ept;
  83
  84         spinlock_t queue_lock;
  85         struct sk_buff_head queue;
  86         wait_queue_head_t readq;
  87 };
  88
  89 static int rpmsg_eptdev_destroy(struct device *dev, void *data)
  90 {
  91         struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
  92
  93         mutex_lock(&eptdev->ept_lock);
  94         if (eptdev->ept) {
  95                 rpmsg_destroy_ept(eptdev->ept);
  96                 eptdev->ept = NULL;
  97         }
  98         mutex_unlock(&eptdev->ept_lock);
  99
 100         /* wake up any blocked readers */
 101         wake_up_interruptible(&eptdev->readq);
 102
 103         device_del(&eptdev->dev);
 104         put_device(&eptdev->dev);
 105
 106         return 0;
 107 }
 108
 109 static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
 110                         void *priv, u32 addr)
 111 {
 112         struct rpmsg_eptdev *eptdev = priv;
 113         struct sk_buff *skb;
 114
 115         skb = alloc_skb(len, GFP_ATOMIC);
 116         if (!skb)
 117                 return -ENOMEM;
 118
 119         skb_put_data(skb, buf, len);
 120
 121         spin_lock(&eptdev->queue_lock);
 122         skb_queue_tail(&eptdev->queue, skb);
 123         spin_unlock(&eptdev->queue_lock);
 124
 125         /* wake up any blocking processes, waiting for new data */
 126         wake_up_interruptible(&eptdev->readq);
 127
 128         return 0;
 129 }
 130
 131 static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 132 {
 133         struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
 134         struct rpmsg_endpoint *ept;
 135         struct rpmsg_device *rpdev = eptdev->rpdev;
 136         struct device *dev = &eptdev->dev;
 137
 138         get_device(dev);
 139
 140         ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
 141         if (!ept) {
 142                 dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
 143                 put_device(dev);
 144                 return -EINVAL;
 145         }
 146
 147         eptdev->ept = ept;
 148         filp->private_data = eptdev;
 149
 150         return 0;
 151 }
 152
 153 static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
 154 {
 155         struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
 156         struct device *dev = &eptdev->dev;
 157         struct sk_buff *skb;
 158
 159         /* Close the endpoint, if it's not already destroyed by the parent */
 160         mutex_lock(&eptdev->ept_lock);
 161         if (eptdev->ept) {
 162                 rpmsg_destroy_ept(eptdev->ept);
 163                 eptdev->ept = NULL;
 164         }
 165         mutex_unlock(&eptdev->ept_lock);
 166
 167         /* Discard all SKBs */
 168         while (!skb_queue_empty(&eptdev->queue)) {
 169                 skb = skb_dequeue(&eptdev->queue);
 170                 kfree_skb(skb);
 171         }
 172
 173         put_device(dev);
 174
 175         return 0;
 176 }
 177
 178 static ssize_t rpmsg_eptdev_read(struct file *filp, char __user *buf,
 179                                  size_t len, loff_t *f_pos)
 180 {
 181         struct rpmsg_eptdev *eptdev = filp->private_data;
 182         unsigned long flags;
 183         struct sk_buff *skb;
 184         int use;
 185
 186         if (!eptdev->ept)
 187                 return -EPIPE;
 188
 189         spin_lock_irqsave(&eptdev->queue_lock, flags);
 190
 191         /* Wait for data in the queue */
 192         if (skb_queue_empty(&eptdev->queue)) {
 193                 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
 194
 195                 if (filp->f_flags & O_NONBLOCK)
 196                         return -EAGAIN;
 197
 198                 /* Wait until we get data or the endpoint goes away */
 199                 if (wait_event_interruptible(eptdev->readq,
 200                                              !skb_queue_empty(&eptdev->queue) ||
 201                                              !eptdev->ept))
 202                         return -ERESTARTSYS;
 203
 204                 /* We lost the endpoint while waiting */
 205                 if (!eptdev->ept)
 206                         return -EPIPE;
 207
 208                 spin_lock_irqsave(&eptdev->queue_lock, flags);
 209         }
 210
 211         skb = skb_dequeue(&eptdev->queue);
 212         spin_unlock_irqrestore(&eptdev->queue_lock, flags);
 213         if (!skb)
 214                 return -EFAULT;
 215
 216         use = min_t(size_t, len, skb->len);
 217         if (copy_to_user(buf, skb->data, use))
 218                 use = -EFAULT;
 219
 220         kfree_skb(skb);
 221
 222         return use;
 223 }
 224
 225 static ssize_t rpmsg_eptdev_write(struct file *filp, const char __user *buf,
 226                                   size_t len, loff_t *f_pos)
 227 {
 228         struct rpmsg_eptdev *eptdev = filp->private_data;
 229         void *kbuf;
 230         int ret;
 231
 232         kbuf = memdup_user(buf, len);
 233         if (IS_ERR(kbuf))
 234                 return PTR_ERR(kbuf);
 235
 236         if (mutex_lock_interruptible(&eptdev->ept_lock)) {
 237                 ret = -ERESTARTSYS;
 238                 goto free_kbuf;
 239         }
 240
 241         if (!eptdev->ept) {
 242                 ret = -EPIPE;
 243                 goto unlock_eptdev;
 244         }
 245
 246         if (filp->f_flags & O_NONBLOCK)
 247                 ret = rpmsg_trysend(eptdev->ept, kbuf, len);
 248         else
 249                 ret = rpmsg_send(eptdev->ept, kbuf, len);
 250
 251 unlock_eptdev:
 252         mutex_unlock(&eptdev->ept_lock);
 253
 254 free_kbuf:
 255         kfree(kbuf);
 256         return ret < 0 ? ret : len;
 257 }
 258
 259 static unsigned int rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 260 {
 261         struct rpmsg_eptdev *eptdev = filp->private_data;
 262         unsigned int mask = 0;
 263
 264         if (!eptdev->ept)
 265                 return POLLERR;
 266
 267         poll_wait(filp, &eptdev->readq, wait);
 268
 269         if (!skb_queue_empty(&eptdev->queue))
 270                 mask |= POLLIN | POLLRDNORM;
 271
 272         mask |= rpmsg_poll(eptdev->ept, filp, wait);
 273
 274         return mask;
 275 }
 276
 277 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 278                                unsigned long arg)
 279 {
 280         struct rpmsg_eptdev *eptdev = fp->private_data;
 281
 282         if (cmd != RPMSG_DESTROY_EPT_IOCTL)
 283                 return -EINVAL;
 284
 285         return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
 286 }
 287
 288 static const struct file_operations rpmsg_eptdev_fops = {
 289         .owner = THIS_MODULE,
 290         .open = rpmsg_eptdev_open,
 291         .release = rpmsg_eptdev_release,
 292         .read = rpmsg_eptdev_read,
 293         .write = rpmsg_eptdev_write,
 294         .poll = rpmsg_eptdev_poll,
 295         .unlocked_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 };
 457
 458 static void rpmsg_ctrldev_release_device(struct device *dev)
 459 {
 460         struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
 461
 462         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 463         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 464         cdev_del(&ctrldev->cdev);
 465         kfree(ctrldev);
 466 }
 467
 468 static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
 469 {
 470         struct rpmsg_ctrldev *ctrldev;
 471         struct device *dev;
 472         int ret;
 473
 474         ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
 475         if (!ctrldev)
 476                 return -ENOMEM;
 477
 478         ctrldev->rpdev = rpdev;
 479
 480         dev = &ctrldev->dev;
 481         device_initialize(dev);
 482         dev->parent = &rpdev->dev;
 483         dev->class = rpmsg_class;
 484
 485         cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
 486         ctrldev->cdev.owner = THIS_MODULE;
 487
 488         ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
 489         if (ret < 0)
 490                 goto free_ctrldev;
 491         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
 492
 493         ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
 494         if (ret < 0)
 495                 goto free_minor_ida;
 496         dev->id = ret;
 497         dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
 498
 499         ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
 500         if (ret)
 501                 goto free_ctrl_ida;
 502
 503         /* We can now rely on the release function for cleanup */
 504         dev->release = rpmsg_ctrldev_release_device;
 505
 506         ret = device_add(dev);
 507         if (ret) {
 508                 dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
 509                 put_device(dev);
 510         }
 511
 512         dev_set_drvdata(&rpdev->dev, ctrldev);
 513
 514         return ret;
 515
 516 free_ctrl_ida:
 517         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
 518 free_minor_ida:
 519         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
 520 free_ctrldev:
 521         put_device(dev);
 522         kfree(ctrldev);
 523
 524         return ret;
 525 }
 526
 527 static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
 528 {
 529         struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
 530         int ret;
 531
 532         /* Destroy all endpoints */
 533         ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
 534         if (ret)
 535                 dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
 536
 537         device_del(&ctrldev->dev);
 538         put_device(&ctrldev->dev);
 539 }
 540
 541 static struct rpmsg_driver rpmsg_chrdev_driver = {
 542         .probe = rpmsg_chrdev_probe,
 543         .remove = rpmsg_chrdev_remove,
 544         .drv = {
 545                 .name = "rpmsg_chrdev",
 546         },
 547 };
 548
 549 static int rpmsg_char_init(void)
 550 {
 551         int ret;
 552
 553         ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
 554         if (ret < 0) {
 555                 pr_err("rpmsg: failed to allocate char dev region\n");
 556                 return ret;
 557         }
 558
 559         rpmsg_class = class_create(THIS_MODULE, "rpmsg");
 560         if (IS_ERR(rpmsg_class)) {
 561                 pr_err("failed to create rpmsg class\n");
 562                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 563                 return PTR_ERR(rpmsg_class);
 564         }
 565
 566         ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
 567         if (ret < 0) {
 568                 pr_err("rpmsgchr: failed to register rpmsg driver\n");
 569                 class_destroy(rpmsg_class);
 570                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 571         }
 572
 573         return ret;
 574 }
 575 postcore_initcall(rpmsg_char_init);
 576
 577 static void rpmsg_chrdev_exit(void)
 578 {
 579         unregister_rpmsg_driver(&rpmsg_chrdev_driver);
 580         class_destroy(rpmsg_class);
 581         unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 582 }
 583 module_exit(rpmsg_chrdev_exit);
 584
 585 MODULE_ALIAS("rpmsg:rpmsg_chrdev");
 586 MODULE_LICENSE("GPL v2");