1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * PPS core file |
4 | * |
5 | * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it> |
6 | */ |
7 | |
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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> |
16 | #include <linux/mutex.h> |
17 | #include <linux/cdev.h> |
18 | #include <linux/poll.h> |
19 | #include <linux/pps_kernel.h> |
20 | #include <linux/slab.h> |
21 | |
22 | #include "kc.h" |
23 | |
24 | /* |
25 | * Local variables |
26 | */ |
27 | |
28 | static dev_t pps_devt; |
29 | static struct class *pps_class; |
30 | |
31 | static DEFINE_MUTEX(pps_idr_lock); |
32 | static DEFINE_IDR(pps_idr); |
33 | |
34 | /* |
35 | * Char device methods |
36 | */ |
37 | |
38 | static __poll_t pps_cdev_poll(struct file *file, poll_table *wait) |
39 | { |
40 | struct pps_device *pps = file->private_data; |
41 | |
42 | poll_wait(filp: file, wait_address: &pps->queue, p: wait); |
43 | |
44 | return EPOLLIN | EPOLLRDNORM; |
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 | |
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 | |
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; |
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: |
101 | dev_dbg(pps->dev, "PPS_GETPARAMS\n" ); |
102 | |
103 | spin_lock_irq(lock: &pps->lock); |
104 | |
105 | /* Get the current parameters */ |
106 | params = pps->params; |
107 | |
108 | spin_unlock_irq(lock: &pps->lock); |
109 | |
110 | err = copy_to_user(to: uarg, from: ¶ms, n: sizeof(struct pps_kparams)); |
111 | if (err) |
112 | return -EFAULT; |
113 | |
114 | break; |
115 | |
116 | case PPS_SETPARAMS: |
117 | dev_dbg(pps->dev, "PPS_SETPARAMS\n" ); |
118 | |
119 | /* Check the capabilities */ |
120 | if (!capable(CAP_SYS_TIME)) |
121 | return -EPERM; |
122 | |
123 | err = copy_from_user(to: ¶ms, from: uarg, n: sizeof(struct pps_kparams)); |
124 | if (err) |
125 | return -EFAULT; |
126 | if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) { |
127 | dev_dbg(pps->dev, "capture mode unspecified (%x)\n" , |
128 | params.mode); |
129 | return -EINVAL; |
130 | } |
131 | |
132 | /* Check for supported capabilities */ |
133 | if ((params.mode & ~pps->info.mode) != 0) { |
134 | dev_dbg(pps->dev, "unsupported capabilities (%x)\n" , |
135 | params.mode); |
136 | return -EINVAL; |
137 | } |
138 | |
139 | spin_lock_irq(lock: &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 */ |
147 | dev_dbg(pps->dev, "time format unspecified (%x)\n" , |
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 | |
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 | |
163 | spin_unlock_irq(lock: &pps->lock); |
164 | |
165 | break; |
166 | |
167 | case PPS_GETCAP: |
168 | dev_dbg(pps->dev, "PPS_GETCAP\n" ); |
169 | |
170 | err = put_user(pps->info.mode, iuarg); |
171 | if (err) |
172 | return -EFAULT; |
173 | |
174 | break; |
175 | |
176 | case PPS_FETCH: { |
177 | struct pps_fdata fdata; |
178 | |
179 | dev_dbg(pps->dev, "PPS_FETCH\n" ); |
180 | |
181 | err = copy_from_user(to: &fdata, from: uarg, n: sizeof(struct pps_fdata)); |
182 | if (err) |
183 | return -EFAULT; |
184 | |
185 | err = pps_cdev_pps_fetch(pps, fdata: &fdata); |
186 | if (err) |
187 | return err; |
188 | |
189 | /* Return the fetched timestamp */ |
190 | spin_lock_irq(lock: &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(lock: &pps->lock); |
199 | |
200 | err = copy_to_user(to: uarg, from: &fdata, n: sizeof(struct pps_fdata)); |
201 | if (err) |
202 | return -EFAULT; |
203 | |
204 | break; |
205 | } |
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(to: &bind_args, from: uarg, |
216 | n: 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: &bind_args); |
236 | if (err < 0) |
237 | return err; |
238 | |
239 | break; |
240 | } |
241 | default: |
242 | return -ENOTTY; |
243 | } |
244 | |
245 | return 0; |
246 | } |
247 | |
248 | #ifdef CONFIG_COMPAT |
249 | static long pps_cdev_compat_ioctl(struct file *file, |
250 | unsigned int cmd, unsigned long arg) |
251 | { |
252 | struct pps_device *pps = file->private_data; |
253 | void __user *uarg = (void __user *) arg; |
254 | |
255 | cmd = _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(void *)); |
256 | |
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(to: &compat, from: uarg, n: 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: &fdata); |
272 | if (err) |
273 | return err; |
274 | |
275 | /* Return the fetched timestamp */ |
276 | spin_lock_irq(lock: &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(lock: &pps->lock); |
288 | |
289 | return copy_to_user(to: uarg, from: &compat, |
290 | n: sizeof(struct pps_fdata_compat)) ? -EFAULT : 0; |
291 | } |
292 | |
293 | return pps_cdev_ioctl(file, cmd, arg); |
294 | } |
295 | #else |
296 | #define pps_cdev_compat_ioctl NULL |
297 | #endif |
298 | |
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); |
303 | file->private_data = pps; |
304 | kobject_get(kobj: &pps->dev->kobj); |
305 | return 0; |
306 | } |
307 | |
308 | static int pps_cdev_release(struct inode *inode, struct file *file) |
309 | { |
310 | struct pps_device *pps = container_of(inode->i_cdev, |
311 | struct pps_device, cdev); |
312 | kobject_put(kobj: &pps->dev->kobj); |
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, |
325 | .compat_ioctl = pps_cdev_compat_ioctl, |
326 | .unlocked_ioctl = pps_cdev_ioctl, |
327 | .open = pps_cdev_open, |
328 | .release = pps_cdev_release, |
329 | }; |
330 | |
331 | static void pps_device_destruct(struct device *dev) |
332 | { |
333 | struct pps_device *pps = dev_get_drvdata(dev); |
334 | |
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); |
339 | mutex_lock(&pps_idr_lock); |
340 | idr_remove(&pps_idr, id: pps->id); |
341 | mutex_unlock(lock: &pps_idr_lock); |
342 | |
343 | kfree(objp: dev); |
344 | kfree(objp: pps); |
345 | } |
346 | |
347 | int pps_register_cdev(struct pps_device *pps) |
348 | { |
349 | int err; |
350 | dev_t devt; |
351 | |
352 | mutex_lock(&pps_idr_lock); |
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. |
356 | */ |
357 | err = idr_alloc(&pps_idr, ptr: pps, start: 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; |
365 | } |
366 | pps->id = err; |
367 | mutex_unlock(lock: &pps_idr_lock); |
368 | |
369 | devt = MKDEV(MAJOR(pps_devt), pps->id); |
370 | |
371 | cdev_init(&pps->cdev, &pps_cdev_fops); |
372 | pps->cdev.owner = pps->info.owner; |
373 | |
374 | err = cdev_add(&pps->cdev, devt, 1); |
375 | if (err) { |
376 | pr_err("%s: failed to add char device %d:%d\n" , |
377 | pps->info.name, MAJOR(pps_devt), pps->id); |
378 | goto free_idr; |
379 | } |
380 | pps->dev = device_create(cls: pps_class, parent: pps->info.dev, devt, drvdata: pps, |
381 | fmt: "pps%d" , pps->id); |
382 | if (IS_ERR(ptr: pps->dev)) { |
383 | err = PTR_ERR(ptr: pps->dev); |
384 | goto del_cdev; |
385 | } |
386 | |
387 | /* Override the release function with our own */ |
388 | pps->dev->release = pps_device_destruct; |
389 | |
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 | |
398 | free_idr: |
399 | mutex_lock(&pps_idr_lock); |
400 | idr_remove(&pps_idr, id: pps->id); |
401 | out_unlock: |
402 | mutex_unlock(lock: &pps_idr_lock); |
403 | return err; |
404 | } |
405 | |
406 | void pps_unregister_cdev(struct pps_device *pps) |
407 | { |
408 | pr_debug("unregistering pps%d\n" , pps->id); |
409 | pps->lookup_cookie = NULL; |
410 | device_destroy(cls: pps_class, devt: pps->dev->devt); |
411 | } |
412 | |
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 | |
445 | /* |
446 | * Module stuff |
447 | */ |
448 | |
449 | static void __exit pps_exit(void) |
450 | { |
451 | class_destroy(cls: 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(name: "pps" ); |
460 | if (IS_ERR(ptr: pps_class)) { |
461 | pr_err("failed to allocate class\n" ); |
462 | return PTR_ERR(ptr: pps_class); |
463 | } |
464 | pps_class->dev_groups = pps_groups; |
465 | |
466 | err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps" ); |
467 | if (err < 0) { |
468 | pr_err("failed to allocate char device region\n" ); |
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(cls: 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" ); |
490 | |