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74ba9207 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
eae9d2ba RG |
2 | /* |
3 | * PPS core file | |
4 | * | |
eae9d2ba | 5 | * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it> |
eae9d2ba RG |
6 | */ |
7 | ||
7f7cce74 | 8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
eae9d2ba RG |
9 | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/uaccess.h> | |
15 | #include <linux/idr.h> | |
2a5cd6e2 | 16 | #include <linux/mutex.h> |
eae9d2ba RG |
17 | #include <linux/cdev.h> |
18 | #include <linux/poll.h> | |
19 | #include <linux/pps_kernel.h> | |
083e5866 | 20 | #include <linux/slab.h> |
eae9d2ba | 21 | |
717c0336 AG |
22 | #include "kc.h" |
23 | ||
eae9d2ba RG |
24 | /* |
25 | * Local variables | |
26 | */ | |
27 | ||
28 | static dev_t pps_devt; | |
29 | static struct class *pps_class; | |
30 | ||
2a5cd6e2 | 31 | static DEFINE_MUTEX(pps_idr_lock); |
083e5866 AG |
32 | static DEFINE_IDR(pps_idr); |
33 | ||
eae9d2ba RG |
34 | /* |
35 | * Char device methods | |
36 | */ | |
37 | ||
afc9a42b | 38 | static __poll_t pps_cdev_poll(struct file *file, poll_table *wait) |
eae9d2ba RG |
39 | { |
40 | struct pps_device *pps = file->private_data; | |
41 | ||
42 | poll_wait(file, &pps->queue, wait); | |
43 | ||
a9a08845 | 44 | return EPOLLIN | EPOLLRDNORM; |
eae9d2ba RG |
45 | } |
46 | ||
47 | static int pps_cdev_fasync(int fd, struct file *file, int on) | |
48 | { | |
49 | struct pps_device *pps = file->private_data; | |
50 | return fasync_helper(fd, file, on, &pps->async_queue); | |
51 | } | |
52 | ||
c2a49fe8 MR |
53 | static int pps_cdev_pps_fetch(struct pps_device *pps, struct pps_fdata *fdata) |
54 | { | |
55 | unsigned int ev = pps->last_ev; | |
56 | int err = 0; | |
57 | ||
58 | /* Manage the timeout */ | |
59 | if (fdata->timeout.flags & PPS_TIME_INVALID) | |
60 | err = wait_event_interruptible(pps->queue, | |
61 | ev != pps->last_ev); | |
62 | else { | |
63 | unsigned long ticks; | |
64 | ||
65 | dev_dbg(pps->dev, "timeout %lld.%09d\n", | |
66 | (long long) fdata->timeout.sec, | |
67 | fdata->timeout.nsec); | |
68 | ticks = fdata->timeout.sec * HZ; | |
69 | ticks += fdata->timeout.nsec / (NSEC_PER_SEC / HZ); | |
70 | ||
71 | if (ticks != 0) { | |
72 | err = wait_event_interruptible_timeout( | |
73 | pps->queue, | |
74 | ev != pps->last_ev, | |
75 | ticks); | |
76 | if (err == 0) | |
77 | return -ETIMEDOUT; | |
78 | } | |
79 | } | |
80 | ||
81 | /* Check for pending signals */ | |
82 | if (err == -ERESTARTSYS) { | |
83 | dev_dbg(pps->dev, "pending signal caught\n"); | |
84 | return -EINTR; | |
85 | } | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
eae9d2ba RG |
90 | static long pps_cdev_ioctl(struct file *file, |
91 | unsigned int cmd, unsigned long arg) | |
92 | { | |
93 | struct pps_device *pps = file->private_data; | |
94 | struct pps_kparams params; | |
eae9d2ba RG |
95 | void __user *uarg = (void __user *) arg; |
96 | int __user *iuarg = (int __user *) arg; | |
97 | int err; | |
98 | ||
99 | switch (cmd) { | |
100 | case PPS_GETPARAMS: | |
7f7cce74 | 101 | dev_dbg(pps->dev, "PPS_GETPARAMS\n"); |
eae9d2ba | 102 | |
cbf83cc5 RG |
103 | spin_lock_irq(&pps->lock); |
104 | ||
105 | /* Get the current parameters */ | |
106 | params = pps->params; | |
107 | ||
108 | spin_unlock_irq(&pps->lock); | |
109 | ||
110 | err = copy_to_user(uarg, ¶ms, sizeof(struct pps_kparams)); | |
eae9d2ba RG |
111 | if (err) |
112 | return -EFAULT; | |
113 | ||
114 | break; | |
115 | ||
116 | case PPS_SETPARAMS: | |
7f7cce74 | 117 | dev_dbg(pps->dev, "PPS_SETPARAMS\n"); |
eae9d2ba RG |
118 | |
119 | /* Check the capabilities */ | |
120 | if (!capable(CAP_SYS_TIME)) | |
121 | return -EPERM; | |
122 | ||
123 | err = copy_from_user(¶ms, uarg, sizeof(struct pps_kparams)); | |
124 | if (err) | |
125 | return -EFAULT; | |
126 | if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) { | |
7f7cce74 | 127 | dev_dbg(pps->dev, "capture mode unspecified (%x)\n", |
eae9d2ba RG |
128 | params.mode); |
129 | return -EINVAL; | |
130 | } | |
131 | ||
132 | /* Check for supported capabilities */ | |
133 | if ((params.mode & ~pps->info.mode) != 0) { | |
7f7cce74 | 134 | dev_dbg(pps->dev, "unsupported capabilities (%x)\n", |
eae9d2ba RG |
135 | params.mode); |
136 | return -EINVAL; | |
137 | } | |
138 | ||
139 | spin_lock_irq(&pps->lock); | |
140 | ||
141 | /* Save the new parameters */ | |
142 | pps->params = params; | |
143 | ||
144 | /* Restore the read only parameters */ | |
145 | if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { | |
146 | /* section 3.3 of RFC 2783 interpreted */ | |
7f7cce74 | 147 | dev_dbg(pps->dev, "time format unspecified (%x)\n", |
eae9d2ba RG |
148 | params.mode); |
149 | pps->params.mode |= PPS_TSFMT_TSPEC; | |
150 | } | |
151 | if (pps->info.mode & PPS_CANWAIT) | |
152 | pps->params.mode |= PPS_CANWAIT; | |
153 | pps->params.api_version = PPS_API_VERS; | |
154 | ||
5515e9a6 ML |
155 | /* |
156 | * Clear unused fields of pps_kparams to avoid leaking | |
157 | * uninitialized data of the PPS_SETPARAMS caller via | |
158 | * PPS_GETPARAMS | |
159 | */ | |
160 | pps->params.assert_off_tu.flags = 0; | |
161 | pps->params.clear_off_tu.flags = 0; | |
162 | ||
eae9d2ba RG |
163 | spin_unlock_irq(&pps->lock); |
164 | ||
165 | break; | |
166 | ||
167 | case PPS_GETCAP: | |
7f7cce74 | 168 | dev_dbg(pps->dev, "PPS_GETCAP\n"); |
eae9d2ba RG |
169 | |
170 | err = put_user(pps->info.mode, iuarg); | |
171 | if (err) | |
172 | return -EFAULT; | |
173 | ||
174 | break; | |
175 | ||
86d921f9 AG |
176 | case PPS_FETCH: { |
177 | struct pps_fdata fdata; | |
178 | ||
7f7cce74 | 179 | dev_dbg(pps->dev, "PPS_FETCH\n"); |
eae9d2ba RG |
180 | |
181 | err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata)); | |
182 | if (err) | |
183 | return -EFAULT; | |
184 | ||
c2a49fe8 MR |
185 | err = pps_cdev_pps_fetch(pps, &fdata); |
186 | if (err) | |
187 | return err; | |
eae9d2ba RG |
188 | |
189 | /* Return the fetched timestamp */ | |
190 | spin_lock_irq(&pps->lock); | |
191 | ||
192 | fdata.info.assert_sequence = pps->assert_sequence; | |
193 | fdata.info.clear_sequence = pps->clear_sequence; | |
194 | fdata.info.assert_tu = pps->assert_tu; | |
195 | fdata.info.clear_tu = pps->clear_tu; | |
196 | fdata.info.current_mode = pps->current_mode; | |
197 | ||
198 | spin_unlock_irq(&pps->lock); | |
199 | ||
200 | err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata)); | |
201 | if (err) | |
202 | return -EFAULT; | |
203 | ||
204 | break; | |
86d921f9 | 205 | } |
717c0336 AG |
206 | case PPS_KC_BIND: { |
207 | struct pps_bind_args bind_args; | |
208 | ||
209 | dev_dbg(pps->dev, "PPS_KC_BIND\n"); | |
210 | ||
211 | /* Check the capabilities */ | |
212 | if (!capable(CAP_SYS_TIME)) | |
213 | return -EPERM; | |
214 | ||
215 | if (copy_from_user(&bind_args, uarg, | |
216 | sizeof(struct pps_bind_args))) | |
217 | return -EFAULT; | |
218 | ||
219 | /* Check for supported capabilities */ | |
220 | if ((bind_args.edge & ~pps->info.mode) != 0) { | |
221 | dev_err(pps->dev, "unsupported capabilities (%x)\n", | |
222 | bind_args.edge); | |
223 | return -EINVAL; | |
224 | } | |
225 | ||
226 | /* Validate parameters roughly */ | |
227 | if (bind_args.tsformat != PPS_TSFMT_TSPEC || | |
228 | (bind_args.edge & ~PPS_CAPTUREBOTH) != 0 || | |
229 | bind_args.consumer != PPS_KC_HARDPPS) { | |
230 | dev_err(pps->dev, "invalid kernel consumer bind" | |
231 | " parameters (%x)\n", bind_args.edge); | |
232 | return -EINVAL; | |
233 | } | |
234 | ||
235 | err = pps_kc_bind(pps, &bind_args); | |
236 | if (err < 0) | |
237 | return err; | |
238 | ||
239 | break; | |
240 | } | |
eae9d2ba RG |
241 | default: |
242 | return -ENOTTY; | |
eae9d2ba RG |
243 | } |
244 | ||
245 | return 0; | |
246 | } | |
247 | ||
2ac66657 MR |
248 | #ifdef CONFIG_COMPAT |
249 | static long pps_cdev_compat_ioctl(struct file *file, | |
250 | unsigned int cmd, unsigned long arg) | |
251 | { | |
c2a49fe8 MR |
252 | struct pps_device *pps = file->private_data; |
253 | void __user *uarg = (void __user *) arg; | |
254 | ||
2ac66657 MR |
255 | cmd = _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(void *)); |
256 | ||
c2a49fe8 MR |
257 | if (cmd == PPS_FETCH) { |
258 | struct pps_fdata_compat compat; | |
259 | struct pps_fdata fdata; | |
260 | int err; | |
261 | ||
262 | dev_dbg(pps->dev, "PPS_FETCH\n"); | |
263 | ||
264 | err = copy_from_user(&compat, uarg, sizeof(struct pps_fdata_compat)); | |
265 | if (err) | |
266 | return -EFAULT; | |
267 | ||
268 | memcpy(&fdata.timeout, &compat.timeout, | |
269 | sizeof(struct pps_ktime_compat)); | |
270 | ||
271 | err = pps_cdev_pps_fetch(pps, &fdata); | |
272 | if (err) | |
273 | return err; | |
274 | ||
275 | /* Return the fetched timestamp */ | |
276 | spin_lock_irq(&pps->lock); | |
277 | ||
278 | compat.info.assert_sequence = pps->assert_sequence; | |
279 | compat.info.clear_sequence = pps->clear_sequence; | |
280 | compat.info.current_mode = pps->current_mode; | |
281 | ||
282 | memcpy(&compat.info.assert_tu, &pps->assert_tu, | |
283 | sizeof(struct pps_ktime_compat)); | |
284 | memcpy(&compat.info.clear_tu, &pps->clear_tu, | |
285 | sizeof(struct pps_ktime_compat)); | |
286 | ||
287 | spin_unlock_irq(&pps->lock); | |
288 | ||
289 | return copy_to_user(uarg, &compat, | |
290 | sizeof(struct pps_fdata_compat)) ? -EFAULT : 0; | |
291 | } | |
292 | ||
2ac66657 MR |
293 | return pps_cdev_ioctl(file, cmd, arg); |
294 | } | |
295 | #else | |
296 | #define pps_cdev_compat_ioctl NULL | |
297 | #endif | |
298 | ||
eae9d2ba RG |
299 | static int pps_cdev_open(struct inode *inode, struct file *file) |
300 | { | |
301 | struct pps_device *pps = container_of(inode->i_cdev, | |
302 | struct pps_device, cdev); | |
eae9d2ba | 303 | file->private_data = pps; |
d953e0e8 | 304 | kobject_get(&pps->dev->kobj); |
eae9d2ba RG |
305 | return 0; |
306 | } | |
307 | ||
308 | static int pps_cdev_release(struct inode *inode, struct file *file) | |
309 | { | |
d953e0e8 GS |
310 | struct pps_device *pps = container_of(inode->i_cdev, |
311 | struct pps_device, cdev); | |
312 | kobject_put(&pps->dev->kobj); | |
eae9d2ba RG |
313 | return 0; |
314 | } | |
315 | ||
316 | /* | |
317 | * Char device stuff | |
318 | */ | |
319 | ||
320 | static const struct file_operations pps_cdev_fops = { | |
321 | .owner = THIS_MODULE, | |
322 | .llseek = no_llseek, | |
323 | .poll = pps_cdev_poll, | |
324 | .fasync = pps_cdev_fasync, | |
2ac66657 | 325 | .compat_ioctl = pps_cdev_compat_ioctl, |
eae9d2ba RG |
326 | .unlocked_ioctl = pps_cdev_ioctl, |
327 | .open = pps_cdev_open, | |
328 | .release = pps_cdev_release, | |
329 | }; | |
330 | ||
083e5866 AG |
331 | static void pps_device_destruct(struct device *dev) |
332 | { | |
333 | struct pps_device *pps = dev_get_drvdata(dev); | |
334 | ||
d953e0e8 GS |
335 | cdev_del(&pps->cdev); |
336 | ||
337 | /* Now we can release the ID for re-use */ | |
338 | pr_debug("deallocating pps%d\n", pps->id); | |
2a5cd6e2 | 339 | mutex_lock(&pps_idr_lock); |
083e5866 | 340 | idr_remove(&pps_idr, pps->id); |
2a5cd6e2 | 341 | mutex_unlock(&pps_idr_lock); |
083e5866 AG |
342 | |
343 | kfree(dev); | |
344 | kfree(pps); | |
345 | } | |
346 | ||
eae9d2ba RG |
347 | int pps_register_cdev(struct pps_device *pps) |
348 | { | |
349 | int err; | |
5e196d34 AG |
350 | dev_t devt; |
351 | ||
2a5cd6e2 | 352 | mutex_lock(&pps_idr_lock); |
19dd2da3 TH |
353 | /* |
354 | * Get new ID for the new PPS source. After idr_alloc() calling | |
355 | * the new source will be freely available into the kernel. | |
083e5866 | 356 | */ |
19dd2da3 TH |
357 | err = idr_alloc(&pps_idr, pps, 0, PPS_MAX_SOURCES, GFP_KERNEL); |
358 | if (err < 0) { | |
359 | if (err == -ENOSPC) { | |
360 | pr_err("%s: too many PPS sources in the system\n", | |
361 | pps->info.name); | |
362 | err = -EBUSY; | |
363 | } | |
364 | goto out_unlock; | |
083e5866 | 365 | } |
19dd2da3 TH |
366 | pps->id = err; |
367 | mutex_unlock(&pps_idr_lock); | |
083e5866 | 368 | |
5e196d34 | 369 | devt = MKDEV(MAJOR(pps_devt), pps->id); |
eae9d2ba | 370 | |
eae9d2ba RG |
371 | cdev_init(&pps->cdev, &pps_cdev_fops); |
372 | pps->cdev.owner = pps->info.owner; | |
373 | ||
5e196d34 | 374 | err = cdev_add(&pps->cdev, devt, 1); |
eae9d2ba | 375 | if (err) { |
7f7cce74 | 376 | pr_err("%s: failed to add char device %d:%d\n", |
eae9d2ba | 377 | pps->info.name, MAJOR(pps_devt), pps->id); |
083e5866 | 378 | goto free_idr; |
eae9d2ba | 379 | } |
5e196d34 | 380 | pps->dev = device_create(pps_class, pps->info.dev, devt, pps, |
eae9d2ba | 381 | "pps%d", pps->id); |
668f06b9 EG |
382 | if (IS_ERR(pps->dev)) { |
383 | err = PTR_ERR(pps->dev); | |
eae9d2ba | 384 | goto del_cdev; |
668f06b9 | 385 | } |
eae9d2ba | 386 | |
d953e0e8 | 387 | /* Override the release function with our own */ |
083e5866 AG |
388 | pps->dev->release = pps_device_destruct; |
389 | ||
eae9d2ba RG |
390 | pr_debug("source %s got cdev (%d:%d)\n", pps->info.name, |
391 | MAJOR(pps_devt), pps->id); | |
392 | ||
393 | return 0; | |
394 | ||
395 | del_cdev: | |
396 | cdev_del(&pps->cdev); | |
397 | ||
083e5866 | 398 | free_idr: |
2a5cd6e2 | 399 | mutex_lock(&pps_idr_lock); |
083e5866 | 400 | idr_remove(&pps_idr, pps->id); |
19dd2da3 | 401 | out_unlock: |
2a5cd6e2 | 402 | mutex_unlock(&pps_idr_lock); |
eae9d2ba RG |
403 | return err; |
404 | } | |
405 | ||
406 | void pps_unregister_cdev(struct pps_device *pps) | |
407 | { | |
d953e0e8 | 408 | pr_debug("unregistering pps%d\n", pps->id); |
513b032c | 409 | pps->lookup_cookie = NULL; |
5e196d34 | 410 | device_destroy(pps_class, pps->dev->devt); |
eae9d2ba RG |
411 | } |
412 | ||
513b032c GS |
413 | /* |
414 | * Look up a pps device by magic cookie. | |
415 | * The cookie is usually a pointer to some enclosing device, but this | |
416 | * code doesn't care; you should never be dereferencing it. | |
417 | * | |
418 | * This is a bit of a kludge that is currently used only by the PPS | |
419 | * serial line discipline. It may need to be tweaked when a second user | |
420 | * is found. | |
421 | * | |
422 | * There is no function interface for setting the lookup_cookie field. | |
423 | * It's initialized to NULL when the pps device is created, and if a | |
424 | * client wants to use it, just fill it in afterward. | |
425 | * | |
426 | * The cookie is automatically set to NULL in pps_unregister_source() | |
427 | * so that it will not be used again, even if the pps device cannot | |
428 | * be removed from the idr due to pending references holding the minor | |
429 | * number in use. | |
430 | */ | |
431 | struct pps_device *pps_lookup_dev(void const *cookie) | |
432 | { | |
433 | struct pps_device *pps; | |
434 | unsigned id; | |
435 | ||
436 | rcu_read_lock(); | |
437 | idr_for_each_entry(&pps_idr, pps, id) | |
438 | if (cookie == pps->lookup_cookie) | |
439 | break; | |
440 | rcu_read_unlock(); | |
441 | return pps; | |
442 | } | |
443 | EXPORT_SYMBOL(pps_lookup_dev); | |
444 | ||
eae9d2ba RG |
445 | /* |
446 | * Module stuff | |
447 | */ | |
448 | ||
449 | static void __exit pps_exit(void) | |
450 | { | |
451 | class_destroy(pps_class); | |
452 | unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES); | |
453 | } | |
454 | ||
455 | static int __init pps_init(void) | |
456 | { | |
457 | int err; | |
458 | ||
459 | pps_class = class_create(THIS_MODULE, "pps"); | |
7ad12566 | 460 | if (IS_ERR(pps_class)) { |
7f7cce74 | 461 | pr_err("failed to allocate class\n"); |
7ad12566 | 462 | return PTR_ERR(pps_class); |
eae9d2ba | 463 | } |
bd0eae4e | 464 | pps_class->dev_groups = pps_groups; |
eae9d2ba RG |
465 | |
466 | err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps"); | |
467 | if (err < 0) { | |
7f7cce74 | 468 | pr_err("failed to allocate char device region\n"); |
eae9d2ba RG |
469 | goto remove_class; |
470 | } | |
471 | ||
472 | pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS); | |
473 | pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti " | |
474 | "<giometti@linux.it>\n", PPS_VERSION); | |
475 | ||
476 | return 0; | |
477 | ||
478 | remove_class: | |
479 | class_destroy(pps_class); | |
480 | ||
481 | return err; | |
482 | } | |
483 | ||
484 | subsys_initcall(pps_init); | |
485 | module_exit(pps_exit); | |
486 | ||
487 | MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); | |
488 | MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION); | |
489 | MODULE_LICENSE("GPL"); |