1 // SPDX-License-Identifier: GPL-2.0
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.
10 * Based on rpmsg performance statistics driver by Michal Simek, which in turn
11 * was based on TI & Google OMX rpmsg driver.
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/cdev.h>
17 #include <linux/device.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>
29 #include "rpmsg_char.h"
30 #include "rpmsg_internal.h"
32 #define RPMSG_DEV_MAX (MINORMASK + 1)
34 static dev_t rpmsg_major;
36 static DEFINE_IDA(rpmsg_ept_ida);
37 static DEFINE_IDA(rpmsg_minor_ida);
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)
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.
60 struct rpmsg_device *rpdev;
61 struct rpmsg_channel_info chinfo;
63 struct mutex ept_lock;
64 struct rpmsg_endpoint *ept;
65 struct rpmsg_endpoint *default_ept;
67 spinlock_t queue_lock;
68 struct sk_buff_head queue;
69 wait_queue_head_t readq;
73 int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
75 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
77 mutex_lock(&eptdev->ept_lock);
79 rpmsg_destroy_ept(eptdev->ept);
82 mutex_unlock(&eptdev->ept_lock);
84 /* wake up any blocked readers */
85 wake_up_interruptible(&eptdev->readq);
87 cdev_device_del(&eptdev->cdev, &eptdev->dev);
88 put_device(&eptdev->dev);
92 EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy);
94 static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
97 struct rpmsg_eptdev *eptdev = priv;
100 skb = alloc_skb(len, GFP_ATOMIC);
104 skb_put_data(skb, buf, len);
106 spin_lock(&eptdev->queue_lock);
107 skb_queue_tail(&eptdev->queue, skb);
108 spin_unlock(&eptdev->queue_lock);
110 /* wake up any blocking processes, waiting for new data */
111 wake_up_interruptible(&eptdev->readq);
116 static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
118 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
119 struct rpmsg_endpoint *ept;
120 struct rpmsg_device *rpdev = eptdev->rpdev;
121 struct device *dev = &eptdev->dev;
123 mutex_lock(&eptdev->ept_lock);
125 mutex_unlock(&eptdev->ept_lock);
132 * If the default_ept is set, the rpmsg device default endpoint is used.
133 * Else a new endpoint is created on open that will be destroyed on release.
135 if (eptdev->default_ept)
136 ept = eptdev->default_ept;
138 ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
141 dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
143 mutex_unlock(&eptdev->ept_lock);
148 filp->private_data = eptdev;
149 mutex_unlock(&eptdev->ept_lock);
154 static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
156 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
157 struct device *dev = &eptdev->dev;
159 /* Close the endpoint, if it's not already destroyed by the parent */
160 mutex_lock(&eptdev->ept_lock);
162 if (!eptdev->default_ept)
163 rpmsg_destroy_ept(eptdev->ept);
166 mutex_unlock(&eptdev->ept_lock);
168 /* Discard all SKBs */
169 skb_queue_purge(&eptdev->queue);
176 static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
178 struct file *filp = iocb->ki_filp;
179 struct rpmsg_eptdev *eptdev = filp->private_data;
187 spin_lock_irqsave(&eptdev->queue_lock, flags);
189 /* Wait for data in the queue */
190 if (skb_queue_empty(&eptdev->queue)) {
191 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
193 if (filp->f_flags & O_NONBLOCK)
196 /* Wait until we get data or the endpoint goes away */
197 if (wait_event_interruptible(eptdev->readq,
198 !skb_queue_empty(&eptdev->queue) ||
202 /* We lost the endpoint while waiting */
206 spin_lock_irqsave(&eptdev->queue_lock, flags);
209 skb = skb_dequeue(&eptdev->queue);
210 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
214 use = min_t(size_t, iov_iter_count(to), skb->len);
215 if (copy_to_iter(skb->data, use, to) != use)
223 static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
224 struct iov_iter *from)
226 struct file *filp = iocb->ki_filp;
227 struct rpmsg_eptdev *eptdev = filp->private_data;
228 size_t len = iov_iter_count(from);
232 kbuf = kzalloc(len, GFP_KERNEL);
236 if (!copy_from_iter_full(kbuf, len, from)) {
241 if (mutex_lock_interruptible(&eptdev->ept_lock)) {
251 if (filp->f_flags & O_NONBLOCK) {
252 ret = rpmsg_trysendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
256 ret = rpmsg_sendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
260 mutex_unlock(&eptdev->ept_lock);
264 return ret < 0 ? ret : len;
267 static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
269 struct rpmsg_eptdev *eptdev = filp->private_data;
275 poll_wait(filp, &eptdev->readq, wait);
277 if (!skb_queue_empty(&eptdev->queue))
278 mask |= EPOLLIN | EPOLLRDNORM;
280 mask |= rpmsg_poll(eptdev->ept, filp, wait);
285 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
288 struct rpmsg_eptdev *eptdev = fp->private_data;
290 if (cmd != RPMSG_DESTROY_EPT_IOCTL)
293 /* Don't allow to destroy a default endpoint. */
294 if (eptdev->default_ept)
297 return rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL);
300 static const struct file_operations rpmsg_eptdev_fops = {
301 .owner = THIS_MODULE,
302 .open = rpmsg_eptdev_open,
303 .release = rpmsg_eptdev_release,
304 .read_iter = rpmsg_eptdev_read_iter,
305 .write_iter = rpmsg_eptdev_write_iter,
306 .poll = rpmsg_eptdev_poll,
307 .unlocked_ioctl = rpmsg_eptdev_ioctl,
308 .compat_ioctl = compat_ptr_ioctl,
311 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
314 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
316 return sprintf(buf, "%s\n", eptdev->chinfo.name);
318 static DEVICE_ATTR_RO(name);
320 static ssize_t src_show(struct device *dev, struct device_attribute *attr,
323 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
325 return sprintf(buf, "%d\n", eptdev->chinfo.src);
327 static DEVICE_ATTR_RO(src);
329 static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
332 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
334 return sprintf(buf, "%d\n", eptdev->chinfo.dst);
336 static DEVICE_ATTR_RO(dst);
338 static struct attribute *rpmsg_eptdev_attrs[] = {
344 ATTRIBUTE_GROUPS(rpmsg_eptdev);
346 static void rpmsg_eptdev_release_device(struct device *dev)
348 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
350 ida_simple_remove(&rpmsg_ept_ida, dev->id);
351 ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
355 static struct rpmsg_eptdev *rpmsg_chrdev_eptdev_alloc(struct rpmsg_device *rpdev,
356 struct device *parent)
358 struct rpmsg_eptdev *eptdev;
361 eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
363 return ERR_PTR(-ENOMEM);
366 eptdev->rpdev = rpdev;
368 mutex_init(&eptdev->ept_lock);
369 spin_lock_init(&eptdev->queue_lock);
370 skb_queue_head_init(&eptdev->queue);
371 init_waitqueue_head(&eptdev->readq);
373 device_initialize(dev);
374 dev->class = rpmsg_class;
375 dev->parent = parent;
376 dev->groups = rpmsg_eptdev_groups;
377 dev_set_drvdata(dev, eptdev);
379 cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
380 eptdev->cdev.owner = THIS_MODULE;
385 static int rpmsg_chrdev_eptdev_add(struct rpmsg_eptdev *eptdev, struct rpmsg_channel_info chinfo)
387 struct device *dev = &eptdev->dev;
390 eptdev->chinfo = chinfo;
392 ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
395 dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
397 ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
401 dev_set_name(dev, "rpmsg%d", ret);
403 ret = cdev_device_add(&eptdev->cdev, &eptdev->dev);
407 /* We can now rely on the release function for cleanup */
408 dev->release = rpmsg_eptdev_release_device;
413 ida_simple_remove(&rpmsg_ept_ida, dev->id);
415 ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
423 int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent,
424 struct rpmsg_channel_info chinfo)
426 struct rpmsg_eptdev *eptdev;
429 eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, parent);
431 return PTR_ERR(eptdev);
433 ret = rpmsg_chrdev_eptdev_add(eptdev, chinfo);
437 EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create);
439 static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
441 struct rpmsg_channel_info chinfo;
442 struct rpmsg_eptdev *eptdev;
443 struct device *dev = &rpdev->dev;
445 memcpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
446 chinfo.src = rpdev->src;
447 chinfo.dst = rpdev->dst;
449 eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, dev);
451 return PTR_ERR(eptdev);
453 /* Set the default_ept to the rpmsg device endpoint */
454 eptdev->default_ept = rpdev->ept;
457 * The rpmsg_ept_cb uses *priv parameter to get its rpmsg_eptdev context.
458 * Storedit in default_ept *priv field.
460 eptdev->default_ept->priv = eptdev;
462 return rpmsg_chrdev_eptdev_add(eptdev, chinfo);
465 static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
469 ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
471 dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
474 static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
475 { .name = "rpmsg-raw" },
479 static struct rpmsg_driver rpmsg_chrdev_driver = {
480 .probe = rpmsg_chrdev_probe,
481 .remove = rpmsg_chrdev_remove,
482 .callback = rpmsg_ept_cb,
483 .id_table = rpmsg_chrdev_id_table,
484 .drv.name = "rpmsg_chrdev",
487 static int rpmsg_chrdev_init(void)
491 ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
493 pr_err("failed to allocate char dev region\n");
497 ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
499 pr_err("rpmsg: failed to register rpmsg raw driver\n");
506 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
510 postcore_initcall(rpmsg_chrdev_init);
512 static void rpmsg_chrdev_exit(void)
514 unregister_rpmsg_driver(&rpmsg_chrdev_driver);
515 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
517 module_exit(rpmsg_chrdev_exit);
519 MODULE_ALIAS("rpmsg:rpmsg_chrdev");
520 MODULE_LICENSE("GPL v2");