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 */ 56 struct rpmsg_eptdev { 57 struct device dev; 58 struct cdev cdev; 59 60 struct rpmsg_device *rpdev; 61 struct rpmsg_channel_info chinfo; 62 63 struct mutex ept_lock; 64 struct rpmsg_endpoint *ept; 65 struct rpmsg_endpoint *default_ept; 66 67 spinlock_t queue_lock; 68 struct sk_buff_head queue; 69 wait_queue_head_t readq; 70 71 }; 72 73 int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) 74 { 75 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev); 76 77 mutex_lock(&eptdev->ept_lock); 78 if (eptdev->ept) { 79 /* The default endpoint is released by the rpmsg core */ 80 if (!eptdev->default_ept) 81 rpmsg_destroy_ept(eptdev->ept); 82 eptdev->ept = NULL; 83 } 84 mutex_unlock(&eptdev->ept_lock); 85 86 /* wake up any blocked readers */ 87 wake_up_interruptible(&eptdev->readq); 88 89 cdev_device_del(&eptdev->cdev, &eptdev->dev); 90 put_device(&eptdev->dev); 91 92 return 0; 93 } 94 EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy); 95 96 static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len, 97 void *priv, u32 addr) 98 { 99 struct rpmsg_eptdev *eptdev = priv; 100 struct sk_buff *skb; 101 102 skb = alloc_skb(len, GFP_ATOMIC); 103 if (!skb) 104 return -ENOMEM; 105 106 skb_put_data(skb, buf, len); 107 108 spin_lock(&eptdev->queue_lock); 109 skb_queue_tail(&eptdev->queue, skb); 110 spin_unlock(&eptdev->queue_lock); 111 112 /* wake up any blocking processes, waiting for new data */ 113 wake_up_interruptible(&eptdev->readq); 114 115 return 0; 116 } 117 118 static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) 119 { 120 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev); 121 struct rpmsg_endpoint *ept; 122 struct rpmsg_device *rpdev = eptdev->rpdev; 123 struct device *dev = &eptdev->dev; 124 125 mutex_lock(&eptdev->ept_lock); 126 if (eptdev->ept) { 127 mutex_unlock(&eptdev->ept_lock); 128 return -EBUSY; 129 } 130 131 get_device(dev); 132 133 /* 134 * If the default_ept is set, the rpmsg device default endpoint is used. 135 * Else a new endpoint is created on open that will be destroyed on release. 136 */ 137 if (eptdev->default_ept) 138 ept = eptdev->default_ept; 139 else 140 ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo); 141 142 if (!ept) { 143 dev_err(dev, "failed to open %s\n", eptdev->chinfo.name); 144 put_device(dev); 145 mutex_unlock(&eptdev->ept_lock); 146 return -EINVAL; 147 } 148 149 eptdev->ept = ept; 150 filp->private_data = eptdev; 151 mutex_unlock(&eptdev->ept_lock); 152 153 return 0; 154 } 155 156 static int rpmsg_eptdev_release(struct inode *inode, struct file *filp) 157 { 158 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev); 159 struct device *dev = &eptdev->dev; 160 161 /* Close the endpoint, if it's not already destroyed by the parent */ 162 mutex_lock(&eptdev->ept_lock); 163 if (eptdev->ept) { 164 if (!eptdev->default_ept) 165 rpmsg_destroy_ept(eptdev->ept); 166 eptdev->ept = NULL; 167 } 168 mutex_unlock(&eptdev->ept_lock); 169 170 /* Discard all SKBs */ 171 skb_queue_purge(&eptdev->queue); 172 173 put_device(dev); 174 175 return 0; 176 } 177 178 static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 179 { 180 struct file *filp = iocb->ki_filp; 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, iov_iter_count(to), skb->len); 217 if (copy_to_iter(skb->data, use, to) != use) 218 use = -EFAULT; 219 220 kfree_skb(skb); 221 222 return use; 223 } 224 225 static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb, 226 struct iov_iter *from) 227 { 228 struct file *filp = iocb->ki_filp; 229 struct rpmsg_eptdev *eptdev = filp->private_data; 230 size_t len = iov_iter_count(from); 231 void *kbuf; 232 int ret; 233 234 kbuf = kzalloc(len, GFP_KERNEL); 235 if (!kbuf) 236 return -ENOMEM; 237 238 if (!copy_from_iter_full(kbuf, len, from)) { 239 ret = -EFAULT; 240 goto free_kbuf; 241 } 242 243 if (mutex_lock_interruptible(&eptdev->ept_lock)) { 244 ret = -ERESTARTSYS; 245 goto free_kbuf; 246 } 247 248 if (!eptdev->ept) { 249 ret = -EPIPE; 250 goto unlock_eptdev; 251 } 252 253 if (filp->f_flags & O_NONBLOCK) { 254 ret = rpmsg_trysendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst); 255 if (ret == -ENOMEM) 256 ret = -EAGAIN; 257 } else { 258 ret = rpmsg_sendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst); 259 } 260 261 unlock_eptdev: 262 mutex_unlock(&eptdev->ept_lock); 263 264 free_kbuf: 265 kfree(kbuf); 266 return ret < 0 ? ret : len; 267 } 268 269 static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait) 270 { 271 struct rpmsg_eptdev *eptdev = filp->private_data; 272 __poll_t mask = 0; 273 274 if (!eptdev->ept) 275 return EPOLLERR; 276 277 poll_wait(filp, &eptdev->readq, wait); 278 279 if (!skb_queue_empty(&eptdev->queue)) 280 mask |= EPOLLIN | EPOLLRDNORM; 281 282 mask |= rpmsg_poll(eptdev->ept, filp, wait); 283 284 return mask; 285 } 286 287 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd, 288 unsigned long arg) 289 { 290 struct rpmsg_eptdev *eptdev = fp->private_data; 291 292 if (cmd != RPMSG_DESTROY_EPT_IOCTL) 293 return -EINVAL; 294 295 /* Don't allow to destroy a default endpoint. */ 296 if (eptdev->default_ept) 297 return -EINVAL; 298 299 return rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL); 300 } 301 302 static const struct file_operations rpmsg_eptdev_fops = { 303 .owner = THIS_MODULE, 304 .open = rpmsg_eptdev_open, 305 .release = rpmsg_eptdev_release, 306 .read_iter = rpmsg_eptdev_read_iter, 307 .write_iter = rpmsg_eptdev_write_iter, 308 .poll = rpmsg_eptdev_poll, 309 .unlocked_ioctl = rpmsg_eptdev_ioctl, 310 .compat_ioctl = compat_ptr_ioctl, 311 }; 312 313 static ssize_t name_show(struct device *dev, struct device_attribute *attr, 314 char *buf) 315 { 316 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev); 317 318 return sprintf(buf, "%s\n", eptdev->chinfo.name); 319 } 320 static DEVICE_ATTR_RO(name); 321 322 static ssize_t src_show(struct device *dev, struct device_attribute *attr, 323 char *buf) 324 { 325 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev); 326 327 return sprintf(buf, "%d\n", eptdev->chinfo.src); 328 } 329 static DEVICE_ATTR_RO(src); 330 331 static ssize_t dst_show(struct device *dev, struct device_attribute *attr, 332 char *buf) 333 { 334 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev); 335 336 return sprintf(buf, "%d\n", eptdev->chinfo.dst); 337 } 338 static DEVICE_ATTR_RO(dst); 339 340 static struct attribute *rpmsg_eptdev_attrs[] = { 341 &dev_attr_name.attr, 342 &dev_attr_src.attr, 343 &dev_attr_dst.attr, 344 NULL 345 }; 346 ATTRIBUTE_GROUPS(rpmsg_eptdev); 347 348 static void rpmsg_eptdev_release_device(struct device *dev) 349 { 350 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev); 351 352 ida_simple_remove(&rpmsg_ept_ida, dev->id); 353 ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt)); 354 kfree(eptdev); 355 } 356 357 static struct rpmsg_eptdev *rpmsg_chrdev_eptdev_alloc(struct rpmsg_device *rpdev, 358 struct device *parent) 359 { 360 struct rpmsg_eptdev *eptdev; 361 struct device *dev; 362 363 eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL); 364 if (!eptdev) 365 return ERR_PTR(-ENOMEM); 366 367 dev = &eptdev->dev; 368 eptdev->rpdev = rpdev; 369 370 mutex_init(&eptdev->ept_lock); 371 spin_lock_init(&eptdev->queue_lock); 372 skb_queue_head_init(&eptdev->queue); 373 init_waitqueue_head(&eptdev->readq); 374 375 device_initialize(dev); 376 dev->class = rpmsg_class; 377 dev->parent = parent; 378 dev->groups = rpmsg_eptdev_groups; 379 dev_set_drvdata(dev, eptdev); 380 381 cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops); 382 eptdev->cdev.owner = THIS_MODULE; 383 384 return eptdev; 385 } 386 387 static int rpmsg_chrdev_eptdev_add(struct rpmsg_eptdev *eptdev, struct rpmsg_channel_info chinfo) 388 { 389 struct device *dev = &eptdev->dev; 390 int ret; 391 392 eptdev->chinfo = chinfo; 393 394 ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL); 395 if (ret < 0) 396 goto free_eptdev; 397 dev->devt = MKDEV(MAJOR(rpmsg_major), ret); 398 399 ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL); 400 if (ret < 0) 401 goto free_minor_ida; 402 dev->id = ret; 403 dev_set_name(dev, "rpmsg%d", ret); 404 405 ret = cdev_device_add(&eptdev->cdev, &eptdev->dev); 406 if (ret) 407 goto free_ept_ida; 408 409 /* We can now rely on the release function for cleanup */ 410 dev->release = rpmsg_eptdev_release_device; 411 412 return ret; 413 414 free_ept_ida: 415 ida_simple_remove(&rpmsg_ept_ida, dev->id); 416 free_minor_ida: 417 ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt)); 418 free_eptdev: 419 put_device(dev); 420 kfree(eptdev); 421 422 return ret; 423 } 424 425 int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent, 426 struct rpmsg_channel_info chinfo) 427 { 428 struct rpmsg_eptdev *eptdev; 429 430 eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, parent); 431 if (IS_ERR(eptdev)) 432 return PTR_ERR(eptdev); 433 434 return rpmsg_chrdev_eptdev_add(eptdev, chinfo); 435 } 436 EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create); 437 438 static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) 439 { 440 struct rpmsg_channel_info chinfo; 441 struct rpmsg_eptdev *eptdev; 442 struct device *dev = &rpdev->dev; 443 444 memcpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE); 445 chinfo.src = rpdev->src; 446 chinfo.dst = rpdev->dst; 447 448 eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, dev); 449 if (IS_ERR(eptdev)) 450 return PTR_ERR(eptdev); 451 452 /* Set the default_ept to the rpmsg device endpoint */ 453 eptdev->default_ept = rpdev->ept; 454 455 /* 456 * The rpmsg_ept_cb uses *priv parameter to get its rpmsg_eptdev context. 457 * Storedit in default_ept *priv field. 458 */ 459 eptdev->default_ept->priv = eptdev; 460 461 return rpmsg_chrdev_eptdev_add(eptdev, chinfo); 462 } 463 464 static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev) 465 { 466 int ret; 467 468 ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_eptdev_destroy); 469 if (ret) 470 dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret); 471 } 472 473 static struct rpmsg_device_id rpmsg_chrdev_id_table[] = { 474 { .name = "rpmsg-raw" }, 475 { }, 476 }; 477 478 static struct rpmsg_driver rpmsg_chrdev_driver = { 479 .probe = rpmsg_chrdev_probe, 480 .remove = rpmsg_chrdev_remove, 481 .callback = rpmsg_ept_cb, 482 .id_table = rpmsg_chrdev_id_table, 483 .drv.name = "rpmsg_chrdev", 484 }; 485 486 static int rpmsg_chrdev_init(void) 487 { 488 int ret; 489 490 ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char"); 491 if (ret < 0) { 492 pr_err("failed to allocate char dev region\n"); 493 return ret; 494 } 495 496 ret = register_rpmsg_driver(&rpmsg_chrdev_driver); 497 if (ret < 0) { 498 pr_err("rpmsg: failed to register rpmsg raw driver\n"); 499 goto free_region; 500 } 501 502 return 0; 503 504 free_region: 505 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX); 506 507 return ret; 508 } 509 postcore_initcall(rpmsg_chrdev_init); 510 511 static void rpmsg_chrdev_exit(void) 512 { 513 unregister_rpmsg_driver(&rpmsg_chrdev_driver); 514 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX); 515 } 516 module_exit(rpmsg_chrdev_exit); 517 518 MODULE_ALIAS("rpmsg:rpmsg_chrdev"); 519 MODULE_LICENSE("GPL v2"); 520