1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2022, STMicroelectronics 4 * Copyright (c) 2016, Linaro Ltd. 5 * Copyright (c) 2012, Michal Simek <monstr@monstr.eu> 6 * Copyright (c) 2012, PetaLogix 7 * Copyright (c) 2011, Texas Instruments, Inc. 8 * Copyright (c) 2011, Google, Inc. 9 * 10 * Based on rpmsg performance statistics driver by Michal Simek, which in turn 11 * was based on TI & Google OMX rpmsg driver. 12 */ 13 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 16 #include <linux/cdev.h> 17 #include <linux/device.h> 18 #include <linux/fs.h> 19 #include <linux/idr.h> 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <linux/poll.h> 23 #include <linux/rpmsg.h> 24 #include <linux/skbuff.h> 25 #include <linux/slab.h> 26 #include <linux/uaccess.h> 27 #include <uapi/linux/rpmsg.h> 28 29 #include "rpmsg_char.h" 30 #include "rpmsg_internal.h" 31 32 #define RPMSG_DEV_MAX (MINORMASK + 1) 33 34 static dev_t rpmsg_major; 35 36 static DEFINE_IDA(rpmsg_ept_ida); 37 static DEFINE_IDA(rpmsg_minor_ida); 38 39 #define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev) 40 #define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev) 41 42 /** 43 * struct rpmsg_eptdev - endpoint device context 44 * @dev: endpoint device 45 * @cdev: cdev for the endpoint device 46 * @rpdev: underlaying rpmsg device 47 * @chinfo: info used to open the endpoint 48 * @ept_lock: synchronization of @ept modifications 49 * @ept: rpmsg endpoint reference, when open 50 * @queue_lock: synchronization of @queue operations 51 * @queue: incoming message queue 52 * @readq: wait object for incoming queue 53 * @default_ept: set to channel default endpoint if the default endpoint should be re-used 54 * on device open to prevent endpoint address update. 55 * @remote_flow_restricted: to indicate if the remote has requested for flow to be limited 56 * @remote_flow_updated: to indicate if the flow control has been requested 57 */ 58 struct rpmsg_eptdev { 59 struct device dev; 60 struct cdev cdev; 61 62 struct rpmsg_device *rpdev; 63 struct rpmsg_channel_info chinfo; 64 65 struct mutex ept_lock; 66 struct rpmsg_endpoint *ept; 67 struct rpmsg_endpoint *default_ept; 68 69 spinlock_t queue_lock; 70 struct sk_buff_head queue; 71 wait_queue_head_t readq; 72 73 bool remote_flow_restricted; 74 bool remote_flow_updated; 75 }; 76 77 int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) 78 { 79 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev); 80 81 mutex_lock(&eptdev->ept_lock); 82 eptdev->rpdev = NULL; 83 if (eptdev->ept) { 84 /* The default endpoint is released by the rpmsg core */ 85 if (!eptdev->default_ept) 86 rpmsg_destroy_ept(eptdev->ept); 87 eptdev->ept = NULL; 88 } 89 mutex_unlock(&eptdev->ept_lock); 90 91 /* wake up any blocked readers */ 92 wake_up_interruptible(&eptdev->readq); 93 94 cdev_device_del(&eptdev->cdev, &eptdev->dev); 95 put_device(&eptdev->dev); 96 97 return 0; 98 } 99 EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy); 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_ept_flow_cb(struct rpmsg_device *rpdev, void *priv, bool enable) 124 { 125 struct rpmsg_eptdev *eptdev = priv; 126 127 eptdev->remote_flow_restricted = enable; 128 eptdev->remote_flow_updated = true; 129 130 wake_up_interruptible(&eptdev->readq); 131 132 return 0; 133 } 134 135 static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) 136 { 137 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev); 138 struct rpmsg_endpoint *ept; 139 struct rpmsg_device *rpdev = eptdev->rpdev; 140 struct device *dev = &eptdev->dev; 141 142 mutex_lock(&eptdev->ept_lock); 143 if (eptdev->ept) { 144 mutex_unlock(&eptdev->ept_lock); 145 return -EBUSY; 146 } 147 148 if (!eptdev->rpdev) { 149 mutex_unlock(&eptdev->ept_lock); 150 return -ENETRESET; 151 } 152 153 get_device(dev); 154 155 /* 156 * If the default_ept is set, the rpmsg device default endpoint is used. 157 * Else a new endpoint is created on open that will be destroyed on release. 158 */ 159 if (eptdev->default_ept) 160 ept = eptdev->default_ept; 161 else 162 ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo); 163 164 if (!ept) { 165 dev_err(dev, "failed to open %s\n", eptdev->chinfo.name); 166 put_device(dev); 167 mutex_unlock(&eptdev->ept_lock); 168 return -EINVAL; 169 } 170 171 ept->flow_cb = rpmsg_ept_flow_cb; 172 eptdev->ept = ept; 173 filp->private_data = eptdev; 174 mutex_unlock(&eptdev->ept_lock); 175 176 return 0; 177 } 178 179 static int rpmsg_eptdev_release(struct inode *inode, struct file *filp) 180 { 181 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev); 182 struct device *dev = &eptdev->dev; 183 184 /* Close the endpoint, if it's not already destroyed by the parent */ 185 mutex_lock(&eptdev->ept_lock); 186 if (eptdev->ept) { 187 if (!eptdev->default_ept) 188 rpmsg_destroy_ept(eptdev->ept); 189 eptdev->ept = NULL; 190 } 191 mutex_unlock(&eptdev->ept_lock); 192 eptdev->remote_flow_updated = false; 193 194 /* Discard all SKBs */ 195 skb_queue_purge(&eptdev->queue); 196 197 put_device(dev); 198 199 return 0; 200 } 201 202 static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 203 { 204 struct file *filp = iocb->ki_filp; 205 struct rpmsg_eptdev *eptdev = filp->private_data; 206 unsigned long flags; 207 struct sk_buff *skb; 208 int use; 209 210 if (!eptdev->ept) 211 return -EPIPE; 212 213 spin_lock_irqsave(&eptdev->queue_lock, flags); 214 215 /* Wait for data in the queue */ 216 if (skb_queue_empty(&eptdev->queue)) { 217 spin_unlock_irqrestore(&eptdev->queue_lock, flags); 218 219 if (filp->f_flags & O_NONBLOCK) 220 return -EAGAIN; 221 222 /* Wait until we get data or the endpoint goes away */ 223 if (wait_event_interruptible(eptdev->readq, 224 !skb_queue_empty(&eptdev->queue) || 225 !eptdev->ept)) 226 return -ERESTARTSYS; 227 228 /* We lost the endpoint while waiting */ 229 if (!eptdev->ept) 230 return -EPIPE; 231 232 spin_lock_irqsave(&eptdev->queue_lock, flags); 233 } 234 235 skb = skb_dequeue(&eptdev->queue); 236 spin_unlock_irqrestore(&eptdev->queue_lock, flags); 237 if (!skb) 238 return -EFAULT; 239 240 use = min_t(size_t, iov_iter_count(to), skb->len); 241 if (copy_to_iter(skb->data, use, to) != use) 242 use = -EFAULT; 243 244 kfree_skb(skb); 245 246 return use; 247 } 248 249 static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb, 250 struct iov_iter *from) 251 { 252 struct file *filp = iocb->ki_filp; 253 struct rpmsg_eptdev *eptdev = filp->private_data; 254 size_t len = iov_iter_count(from); 255 void *kbuf; 256 int ret; 257 258 kbuf = kzalloc(len, GFP_KERNEL); 259 if (!kbuf) 260 return -ENOMEM; 261 262 if (!copy_from_iter_full(kbuf, len, from)) { 263 ret = -EFAULT; 264 goto free_kbuf; 265 } 266 267 if (mutex_lock_interruptible(&eptdev->ept_lock)) { 268 ret = -ERESTARTSYS; 269 goto free_kbuf; 270 } 271 272 if (!eptdev->ept) { 273 ret = -EPIPE; 274 goto unlock_eptdev; 275 } 276 277 if (filp->f_flags & O_NONBLOCK) { 278 ret = rpmsg_trysendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst); 279 if (ret == -ENOMEM) 280 ret = -EAGAIN; 281 } else { 282 ret = rpmsg_sendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst); 283 } 284 285 unlock_eptdev: 286 mutex_unlock(&eptdev->ept_lock); 287 288 free_kbuf: 289 kfree(kbuf); 290 return ret < 0 ? ret : len; 291 } 292 293 static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait) 294 { 295 struct rpmsg_eptdev *eptdev = filp->private_data; 296 __poll_t mask = 0; 297 298 if (!eptdev->ept) 299 return EPOLLERR; 300 301 poll_wait(filp, &eptdev->readq, wait); 302 303 if (!skb_queue_empty(&eptdev->queue)) 304 mask |= EPOLLIN | EPOLLRDNORM; 305 306 if (eptdev->remote_flow_updated) 307 mask |= EPOLLPRI; 308 309 mutex_lock(&eptdev->ept_lock); 310 mask |= rpmsg_poll(eptdev->ept, filp, wait); 311 mutex_unlock(&eptdev->ept_lock); 312 313 return mask; 314 } 315 316 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd, 317 unsigned long arg) 318 { 319 struct rpmsg_eptdev *eptdev = fp->private_data; 320 321 bool set; 322 int ret; 323 324 switch (cmd) { 325 case RPMSG_GET_OUTGOING_FLOWCONTROL: 326 eptdev->remote_flow_updated = false; 327 ret = put_user(eptdev->remote_flow_restricted, (int __user *)arg); 328 break; 329 case RPMSG_SET_INCOMING_FLOWCONTROL: 330 if (arg > 1) { 331 ret = -EINVAL; 332 break; 333 } 334 set = !!arg; 335 ret = rpmsg_set_flow_control(eptdev->ept, set, eptdev->chinfo.dst); 336 break; 337 case RPMSG_DESTROY_EPT_IOCTL: 338 /* Don't allow to destroy a default endpoint. */ 339 if (eptdev->default_ept) { 340 ret = -EINVAL; 341 break; 342 } 343 ret = rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL); 344 break; 345 default: 346 ret = -EINVAL; 347 } 348 349 return ret; 350 } 351 352 static const struct file_operations rpmsg_eptdev_fops = { 353 .owner = THIS_MODULE, 354 .open = rpmsg_eptdev_open, 355 .release = rpmsg_eptdev_release, 356 .read_iter = rpmsg_eptdev_read_iter, 357 .write_iter = rpmsg_eptdev_write_iter, 358 .poll = rpmsg_eptdev_poll, 359 .unlocked_ioctl = rpmsg_eptdev_ioctl, 360 .compat_ioctl = compat_ptr_ioctl, 361 }; 362 363 static ssize_t name_show(struct device *dev, struct device_attribute *attr, 364 char *buf) 365 { 366 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev); 367 368 return sprintf(buf, "%s\n", eptdev->chinfo.name); 369 } 370 static DEVICE_ATTR_RO(name); 371 372 static ssize_t src_show(struct device *dev, struct device_attribute *attr, 373 char *buf) 374 { 375 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev); 376 377 return sprintf(buf, "%d\n", eptdev->chinfo.src); 378 } 379 static DEVICE_ATTR_RO(src); 380 381 static ssize_t dst_show(struct device *dev, struct device_attribute *attr, 382 char *buf) 383 { 384 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev); 385 386 return sprintf(buf, "%d\n", eptdev->chinfo.dst); 387 } 388 static DEVICE_ATTR_RO(dst); 389 390 static struct attribute *rpmsg_eptdev_attrs[] = { 391 &dev_attr_name.attr, 392 &dev_attr_src.attr, 393 &dev_attr_dst.attr, 394 NULL 395 }; 396 ATTRIBUTE_GROUPS(rpmsg_eptdev); 397 398 static void rpmsg_eptdev_release_device(struct device *dev) 399 { 400 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev); 401 402 ida_free(&rpmsg_ept_ida, dev->id); 403 ida_free(&rpmsg_minor_ida, MINOR(eptdev->dev.devt)); 404 kfree(eptdev); 405 } 406 407 static struct rpmsg_eptdev *rpmsg_chrdev_eptdev_alloc(struct rpmsg_device *rpdev, 408 struct device *parent) 409 { 410 struct rpmsg_eptdev *eptdev; 411 struct device *dev; 412 413 eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL); 414 if (!eptdev) 415 return ERR_PTR(-ENOMEM); 416 417 dev = &eptdev->dev; 418 eptdev->rpdev = rpdev; 419 420 mutex_init(&eptdev->ept_lock); 421 spin_lock_init(&eptdev->queue_lock); 422 skb_queue_head_init(&eptdev->queue); 423 init_waitqueue_head(&eptdev->readq); 424 425 device_initialize(dev); 426 dev->class = &rpmsg_class; 427 dev->parent = parent; 428 dev->groups = rpmsg_eptdev_groups; 429 dev_set_drvdata(dev, eptdev); 430 431 cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops); 432 eptdev->cdev.owner = THIS_MODULE; 433 434 return eptdev; 435 } 436 437 static int rpmsg_chrdev_eptdev_add(struct rpmsg_eptdev *eptdev, struct rpmsg_channel_info chinfo) 438 { 439 struct device *dev = &eptdev->dev; 440 int ret; 441 442 eptdev->chinfo = chinfo; 443 444 ret = ida_alloc_max(&rpmsg_minor_ida, RPMSG_DEV_MAX - 1, GFP_KERNEL); 445 if (ret < 0) 446 goto free_eptdev; 447 dev->devt = MKDEV(MAJOR(rpmsg_major), ret); 448 449 ret = ida_alloc(&rpmsg_ept_ida, GFP_KERNEL); 450 if (ret < 0) 451 goto free_minor_ida; 452 dev->id = ret; 453 dev_set_name(dev, "rpmsg%d", ret); 454 455 ret = cdev_device_add(&eptdev->cdev, &eptdev->dev); 456 if (ret) 457 goto free_ept_ida; 458 459 /* We can now rely on the release function for cleanup */ 460 dev->release = rpmsg_eptdev_release_device; 461 462 return ret; 463 464 free_ept_ida: 465 ida_free(&rpmsg_ept_ida, dev->id); 466 free_minor_ida: 467 ida_free(&rpmsg_minor_ida, MINOR(dev->devt)); 468 free_eptdev: 469 put_device(dev); 470 kfree(eptdev); 471 472 return ret; 473 } 474 475 int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent, 476 struct rpmsg_channel_info chinfo) 477 { 478 struct rpmsg_eptdev *eptdev; 479 480 eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, parent); 481 if (IS_ERR(eptdev)) 482 return PTR_ERR(eptdev); 483 484 return rpmsg_chrdev_eptdev_add(eptdev, chinfo); 485 } 486 EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create); 487 488 static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) 489 { 490 struct rpmsg_channel_info chinfo; 491 struct rpmsg_eptdev *eptdev; 492 struct device *dev = &rpdev->dev; 493 494 memcpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE); 495 chinfo.src = rpdev->src; 496 chinfo.dst = rpdev->dst; 497 498 eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, dev); 499 if (IS_ERR(eptdev)) 500 return PTR_ERR(eptdev); 501 502 /* Set the default_ept to the rpmsg device endpoint */ 503 eptdev->default_ept = rpdev->ept; 504 505 /* 506 * The rpmsg_ept_cb uses *priv parameter to get its rpmsg_eptdev context. 507 * Storedit in default_ept *priv field. 508 */ 509 eptdev->default_ept->priv = eptdev; 510 511 return rpmsg_chrdev_eptdev_add(eptdev, chinfo); 512 } 513 514 static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev) 515 { 516 int ret; 517 518 ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_eptdev_destroy); 519 if (ret) 520 dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret); 521 } 522 523 static struct rpmsg_device_id rpmsg_chrdev_id_table[] = { 524 { .name = "rpmsg-raw" }, 525 { }, 526 }; 527 528 static struct rpmsg_driver rpmsg_chrdev_driver = { 529 .probe = rpmsg_chrdev_probe, 530 .remove = rpmsg_chrdev_remove, 531 .callback = rpmsg_ept_cb, 532 .id_table = rpmsg_chrdev_id_table, 533 .drv.name = "rpmsg_chrdev", 534 }; 535 536 static int rpmsg_chrdev_init(void) 537 { 538 int ret; 539 540 ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char"); 541 if (ret < 0) { 542 pr_err("failed to allocate char dev region\n"); 543 return ret; 544 } 545 546 ret = register_rpmsg_driver(&rpmsg_chrdev_driver); 547 if (ret < 0) { 548 pr_err("rpmsg: failed to register rpmsg raw driver\n"); 549 goto free_region; 550 } 551 552 return 0; 553 554 free_region: 555 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX); 556 557 return ret; 558 } 559 postcore_initcall(rpmsg_chrdev_init); 560 561 static void rpmsg_chrdev_exit(void) 562 { 563 unregister_rpmsg_driver(&rpmsg_chrdev_driver); 564 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX); 565 } 566 module_exit(rpmsg_chrdev_exit); 567 568 MODULE_ALIAS("rpmsg:rpmsg_chrdev"); 569 MODULE_DESCRIPTION("RPMSG device interface"); 570 MODULE_LICENSE("GPL v2"); 571