1/*
2 * PPS core file
3 *
4 *
5 * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/init.h>
27#include <linux/sched.h>
28#include <linux/uaccess.h>
29#include <linux/idr.h>
30#include <linux/mutex.h>
31#include <linux/cdev.h>
32#include <linux/poll.h>
33#include <linux/pps_kernel.h>
34#include <linux/slab.h>
35
36#include "kc.h"
37
38/*
39 * Local variables
40 */
41
42static dev_t pps_devt;
43static struct class *pps_class;
44
45static DEFINE_MUTEX(pps_idr_lock);
46static DEFINE_IDR(pps_idr);
47
48/*
49 * Char device methods
50 */
51
52static __poll_t pps_cdev_poll(struct file *file, poll_table *wait)
53{
54 struct pps_device *pps = file->private_data;
55
56 poll_wait(file, &pps->queue, wait);
57
58 return EPOLLIN | EPOLLRDNORM;
59}
60
61static int pps_cdev_fasync(int fd, struct file *file, int on)
62{
63 struct pps_device *pps = file->private_data;
64 return fasync_helper(fd, file, on, &pps->async_queue);
65}
66
67static int pps_cdev_pps_fetch(struct pps_device *pps, struct pps_fdata *fdata)
68{
69 unsigned int ev = pps->last_ev;
70 int err = 0;
71
72 /* Manage the timeout */
73 if (fdata->timeout.flags & PPS_TIME_INVALID)
74 err = wait_event_interruptible(pps->queue,
75 ev != pps->last_ev);
76 else {
77 unsigned long ticks;
78
79 dev_dbg(pps->dev, "timeout %lld.%09d\n",
80 (long long) fdata->timeout.sec,
81 fdata->timeout.nsec);
82 ticks = fdata->timeout.sec * HZ;
83 ticks += fdata->timeout.nsec / (NSEC_PER_SEC / HZ);
84
85 if (ticks != 0) {
86 err = wait_event_interruptible_timeout(
87 pps->queue,
88 ev != pps->last_ev,
89 ticks);
90 if (err == 0)
91 return -ETIMEDOUT;
92 }
93 }
94
95 /* Check for pending signals */
96 if (err == -ERESTARTSYS) {
97 dev_dbg(pps->dev, "pending signal caught\n");
98 return -EINTR;
99 }
100
101 return 0;
102}
103
104static long pps_cdev_ioctl(struct file *file,
105 unsigned int cmd, unsigned long arg)
106{
107 struct pps_device *pps = file->private_data;
108 struct pps_kparams params;
109 void __user *uarg = (void __user *) arg;
110 int __user *iuarg = (int __user *) arg;
111 int err;
112
113 switch (cmd) {
114 case PPS_GETPARAMS:
115 dev_dbg(pps->dev, "PPS_GETPARAMS\n");
116
117 spin_lock_irq(&pps->lock);
118
119 /* Get the current parameters */
120 params = pps->params;
121
122 spin_unlock_irq(&pps->lock);
123
124 err = copy_to_user(uarg, &params, sizeof(struct pps_kparams));
125 if (err)
126 return -EFAULT;
127
128 break;
129
130 case PPS_SETPARAMS:
131 dev_dbg(pps->dev, "PPS_SETPARAMS\n");
132
133 /* Check the capabilities */
134 if (!capable(CAP_SYS_TIME))
135 return -EPERM;
136
137 err = copy_from_user(&params, uarg, sizeof(struct pps_kparams));
138 if (err)
139 return -EFAULT;
140 if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) {
141 dev_dbg(pps->dev, "capture mode unspecified (%x)\n",
142 params.mode);
143 return -EINVAL;
144 }
145
146 /* Check for supported capabilities */
147 if ((params.mode & ~pps->info.mode) != 0) {
148 dev_dbg(pps->dev, "unsupported capabilities (%x)\n",
149 params.mode);
150 return -EINVAL;
151 }
152
153 spin_lock_irq(&pps->lock);
154
155 /* Save the new parameters */
156 pps->params = params;
157
158 /* Restore the read only parameters */
159 if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
160 /* section 3.3 of RFC 2783 interpreted */
161 dev_dbg(pps->dev, "time format unspecified (%x)\n",
162 params.mode);
163 pps->params.mode |= PPS_TSFMT_TSPEC;
164 }
165 if (pps->info.mode & PPS_CANWAIT)
166 pps->params.mode |= PPS_CANWAIT;
167 pps->params.api_version = PPS_API_VERS;
168
169 spin_unlock_irq(&pps->lock);
170
171 break;
172
173 case PPS_GETCAP:
174 dev_dbg(pps->dev, "PPS_GETCAP\n");
175
176 err = put_user(pps->info.mode, iuarg);
177 if (err)
178 return -EFAULT;
179
180 break;
181
182 case PPS_FETCH: {
183 struct pps_fdata fdata;
184
185 dev_dbg(pps->dev, "PPS_FETCH\n");
186
187 err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
188 if (err)
189 return -EFAULT;
190
191 err = pps_cdev_pps_fetch(pps, &fdata);
192 if (err)
193 return err;
194
195 /* Return the fetched timestamp */
196 spin_lock_irq(&pps->lock);
197
198 fdata.info.assert_sequence = pps->assert_sequence;
199 fdata.info.clear_sequence = pps->clear_sequence;
200 fdata.info.assert_tu = pps->assert_tu;
201 fdata.info.clear_tu = pps->clear_tu;
202 fdata.info.current_mode = pps->current_mode;
203
204 spin_unlock_irq(&pps->lock);
205
206 err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));
207 if (err)
208 return -EFAULT;
209
210 break;
211 }
212 case PPS_KC_BIND: {
213 struct pps_bind_args bind_args;
214
215 dev_dbg(pps->dev, "PPS_KC_BIND\n");
216
217 /* Check the capabilities */
218 if (!capable(CAP_SYS_TIME))
219 return -EPERM;
220
221 if (copy_from_user(&bind_args, uarg,
222 sizeof(struct pps_bind_args)))
223 return -EFAULT;
224
225 /* Check for supported capabilities */
226 if ((bind_args.edge & ~pps->info.mode) != 0) {
227 dev_err(pps->dev, "unsupported capabilities (%x)\n",
228 bind_args.edge);
229 return -EINVAL;
230 }
231
232 /* Validate parameters roughly */
233 if (bind_args.tsformat != PPS_TSFMT_TSPEC ||
234 (bind_args.edge & ~PPS_CAPTUREBOTH) != 0 ||
235 bind_args.consumer != PPS_KC_HARDPPS) {
236 dev_err(pps->dev, "invalid kernel consumer bind"
237 " parameters (%x)\n", bind_args.edge);
238 return -EINVAL;
239 }
240
241 err = pps_kc_bind(pps, &bind_args);
242 if (err < 0)
243 return err;
244
245 break;
246 }
247 default:
248 return -ENOTTY;
249 }
250
251 return 0;
252}
253
254#ifdef CONFIG_COMPAT
255static long pps_cdev_compat_ioctl(struct file *file,
256 unsigned int cmd, unsigned long arg)
257{
258 struct pps_device *pps = file->private_data;
259 void __user *uarg = (void __user *) arg;
260
261 cmd = _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(void *));
262
263 if (cmd == PPS_FETCH) {
264 struct pps_fdata_compat compat;
265 struct pps_fdata fdata;
266 int err;
267
268 dev_dbg(pps->dev, "PPS_FETCH\n");
269
270 err = copy_from_user(&compat, uarg, sizeof(struct pps_fdata_compat));
271 if (err)
272 return -EFAULT;
273
274 memcpy(&fdata.timeout, &compat.timeout,
275 sizeof(struct pps_ktime_compat));
276
277 err = pps_cdev_pps_fetch(pps, &fdata);
278 if (err)
279 return err;
280
281 /* Return the fetched timestamp */
282 spin_lock_irq(&pps->lock);
283
284 compat.info.assert_sequence = pps->assert_sequence;
285 compat.info.clear_sequence = pps->clear_sequence;
286 compat.info.current_mode = pps->current_mode;
287
288 memcpy(&compat.info.assert_tu, &pps->assert_tu,
289 sizeof(struct pps_ktime_compat));
290 memcpy(&compat.info.clear_tu, &pps->clear_tu,
291 sizeof(struct pps_ktime_compat));
292
293 spin_unlock_irq(&pps->lock);
294
295 return copy_to_user(uarg, &compat,
296 sizeof(struct pps_fdata_compat)) ? -EFAULT : 0;
297 }
298
299 return pps_cdev_ioctl(file, cmd, arg);
300}
301#else
302#define pps_cdev_compat_ioctl NULL
303#endif
304
305static int pps_cdev_open(struct inode *inode, struct file *file)
306{
307 struct pps_device *pps = container_of(inode->i_cdev,
308 struct pps_device, cdev);
309 file->private_data = pps;
310 kobject_get(&pps->dev->kobj);
311 return 0;
312}
313
314static int pps_cdev_release(struct inode *inode, struct file *file)
315{
316 struct pps_device *pps = container_of(inode->i_cdev,
317 struct pps_device, cdev);
318 kobject_put(&pps->dev->kobj);
319 return 0;
320}
321
322/*
323 * Char device stuff
324 */
325
326static const struct file_operations pps_cdev_fops = {
327 .owner = THIS_MODULE,
328 .llseek = no_llseek,
329 .poll = pps_cdev_poll,
330 .fasync = pps_cdev_fasync,
331 .compat_ioctl = pps_cdev_compat_ioctl,
332 .unlocked_ioctl = pps_cdev_ioctl,
333 .open = pps_cdev_open,
334 .release = pps_cdev_release,
335};
336
337static void pps_device_destruct(struct device *dev)
338{
339 struct pps_device *pps = dev_get_drvdata(dev);
340
341 cdev_del(&pps->cdev);
342
343 /* Now we can release the ID for re-use */
344 pr_debug("deallocating pps%d\n", pps->id);
345 mutex_lock(&pps_idr_lock);
346 idr_remove(&pps_idr, pps->id);
347 mutex_unlock(&pps_idr_lock);
348
349 kfree(dev);
350 kfree(pps);
351}
352
353int pps_register_cdev(struct pps_device *pps)
354{
355 int err;
356 dev_t devt;
357
358 mutex_lock(&pps_idr_lock);
359 /*
360 * Get new ID for the new PPS source. After idr_alloc() calling
361 * the new source will be freely available into the kernel.
362 */
363 err = idr_alloc(&pps_idr, pps, 0, PPS_MAX_SOURCES, GFP_KERNEL);
364 if (err < 0) {
365 if (err == -ENOSPC) {
366 pr_err("%s: too many PPS sources in the system\n",
367 pps->info.name);
368 err = -EBUSY;
369 }
370 goto out_unlock;
371 }
372 pps->id = err;
373 mutex_unlock(&pps_idr_lock);
374
375 devt = MKDEV(MAJOR(pps_devt), pps->id);
376
377 cdev_init(&pps->cdev, &pps_cdev_fops);
378 pps->cdev.owner = pps->info.owner;
379
380 err = cdev_add(&pps->cdev, devt, 1);
381 if (err) {
382 pr_err("%s: failed to add char device %d:%d\n",
383 pps->info.name, MAJOR(pps_devt), pps->id);
384 goto free_idr;
385 }
386 pps->dev = device_create(pps_class, pps->info.dev, devt, pps,
387 "pps%d", pps->id);
388 if (IS_ERR(pps->dev)) {
389 err = PTR_ERR(pps->dev);
390 goto del_cdev;
391 }
392
393 /* Override the release function with our own */
394 pps->dev->release = pps_device_destruct;
395
396 pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
397 MAJOR(pps_devt), pps->id);
398
399 return 0;
400
401del_cdev:
402 cdev_del(&pps->cdev);
403
404free_idr:
405 mutex_lock(&pps_idr_lock);
406 idr_remove(&pps_idr, pps->id);
407out_unlock:
408 mutex_unlock(&pps_idr_lock);
409 return err;
410}
411
412void pps_unregister_cdev(struct pps_device *pps)
413{
414 pr_debug("unregistering pps%d\n", pps->id);
415 pps->lookup_cookie = NULL;
416 device_destroy(pps_class, pps->dev->devt);
417}
418
419/*
420 * Look up a pps device by magic cookie.
421 * The cookie is usually a pointer to some enclosing device, but this
422 * code doesn't care; you should never be dereferencing it.
423 *
424 * This is a bit of a kludge that is currently used only by the PPS
425 * serial line discipline. It may need to be tweaked when a second user
426 * is found.
427 *
428 * There is no function interface for setting the lookup_cookie field.
429 * It's initialized to NULL when the pps device is created, and if a
430 * client wants to use it, just fill it in afterward.
431 *
432 * The cookie is automatically set to NULL in pps_unregister_source()
433 * so that it will not be used again, even if the pps device cannot
434 * be removed from the idr due to pending references holding the minor
435 * number in use.
436 */
437struct pps_device *pps_lookup_dev(void const *cookie)
438{
439 struct pps_device *pps;
440 unsigned id;
441
442 rcu_read_lock();
443 idr_for_each_entry(&pps_idr, pps, id)
444 if (cookie == pps->lookup_cookie)
445 break;
446 rcu_read_unlock();
447 return pps;
448}
449EXPORT_SYMBOL(pps_lookup_dev);
450
451/*
452 * Module stuff
453 */
454
455static void __exit pps_exit(void)
456{
457 class_destroy(pps_class);
458 unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
459}
460
461static int __init pps_init(void)
462{
463 int err;
464
465 pps_class = class_create(THIS_MODULE, "pps");
466 if (IS_ERR(pps_class)) {
467 pr_err("failed to allocate class\n");
468 return PTR_ERR(pps_class);
469 }
470 pps_class->dev_groups = pps_groups;
471
472 err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
473 if (err < 0) {
474 pr_err("failed to allocate char device region\n");
475 goto remove_class;
476 }
477
478 pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);
479 pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "
480 "<giometti@linux.it>\n", PPS_VERSION);
481
482 return 0;
483
484remove_class:
485 class_destroy(pps_class);
486
487 return err;
488}
489
490subsys_initcall(pps_init);
491module_exit(pps_exit);
492
493MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
494MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
495MODULE_LICENSE("GPL");
496