projects/linux·blob v3.7 · refs

403 lines · 8.9 KiB

1/*
2 * PPS core file
3 *
4 *
5 * Copyright (C) 2005-2009 Rodolfo Giometti <[email protected]>
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 unsigned int 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 POLLIN | POLLRDNORM;
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 long pps_cdev_ioctl(struct file *file,
68 unsigned int cmd, unsigned long arg)
69{
70 struct pps_device *pps = file->private_data;
71 struct pps_kparams params;
72 void __user *uarg = (void __user *) arg;
73 int __user *iuarg = (int __user *) arg;
74 int err;
75
76 switch (cmd) {
77 case PPS_GETPARAMS:
78 dev_dbg(pps->dev, "PPS_GETPARAMS\n");
79
80 spin_lock_irq(&pps->lock);
81
82 /* Get the current parameters */
83 params = pps->params;
84
85 spin_unlock_irq(&pps->lock);
86
87 err = copy_to_user(uarg, &params, sizeof(struct pps_kparams));
88 if (err)
89 return -EFAULT;
90
91 break;
92
93 case PPS_SETPARAMS:
94 dev_dbg(pps->dev, "PPS_SETPARAMS\n");
95
96 /* Check the capabilities */
97 if (!capable(CAP_SYS_TIME))
98 return -EPERM;
99
100 err = copy_from_user(&params, uarg, sizeof(struct pps_kparams));
101 if (err)
102 return -EFAULT;
103 if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) {
104 dev_dbg(pps->dev, "capture mode unspecified (%x)\n",
105 params.mode);
106 return -EINVAL;
107 }
108
109 /* Check for supported capabilities */
110 if ((params.mode & ~pps->info.mode) != 0) {
111 dev_dbg(pps->dev, "unsupported capabilities (%x)\n",
112 params.mode);
113 return -EINVAL;
114 }
115
116 spin_lock_irq(&pps->lock);
117
118 /* Save the new parameters */
119 pps->params = params;
120
121 /* Restore the read only parameters */
122 if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
123 /* section 3.3 of RFC 2783 interpreted */
124 dev_dbg(pps->dev, "time format unspecified (%x)\n",
125 params.mode);
126 pps->params.mode |= PPS_TSFMT_TSPEC;
127 }
128 if (pps->info.mode & PPS_CANWAIT)
129 pps->params.mode |= PPS_CANWAIT;
130 pps->params.api_version = PPS_API_VERS;
131
132 spin_unlock_irq(&pps->lock);
133
134 break;
135
136 case PPS_GETCAP:
137 dev_dbg(pps->dev, "PPS_GETCAP\n");
138
139 err = put_user(pps->info.mode, iuarg);
140 if (err)
141 return -EFAULT;
142
143 break;
144
145 case PPS_FETCH: {
146 struct pps_fdata fdata;
147 unsigned int ev;
148
149 dev_dbg(pps->dev, "PPS_FETCH\n");
150
151 err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
152 if (err)
153 return -EFAULT;
154
155 ev = pps->last_ev;
156
157 /* Manage the timeout */
158 if (fdata.timeout.flags & PPS_TIME_INVALID)
159 err = wait_event_interruptible(pps->queue,
160 ev != pps->last_ev);
161 else {
162 unsigned long ticks;
163
164 dev_dbg(pps->dev, "timeout %lld.%09d\n",
165 (long long) fdata.timeout.sec,
166 fdata.timeout.nsec);
167 ticks = fdata.timeout.sec * HZ;
168 ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ);
169
170 if (ticks != 0) {
171 err = wait_event_interruptible_timeout(
172 pps->queue,
173 ev != pps->last_ev,
174 ticks);
175 if (err == 0)
176 return -ETIMEDOUT;
177 }
178 }
179
180 /* Check for pending signals */
181 if (err == -ERESTARTSYS) {
182 dev_dbg(pps->dev, "pending signal caught\n");
183 return -EINTR;
184 }
185
186 /* Return the fetched timestamp */
187 spin_lock_irq(&pps->lock);
188
189 fdata.info.assert_sequence = pps->assert_sequence;
190 fdata.info.clear_sequence = pps->clear_sequence;
191 fdata.info.assert_tu = pps->assert_tu;
192 fdata.info.clear_tu = pps->clear_tu;
193 fdata.info.current_mode = pps->current_mode;
194
195 spin_unlock_irq(&pps->lock);
196
197 err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));
198 if (err)
199 return -EFAULT;
200
201 break;
202 }
203 case PPS_KC_BIND: {
204 struct pps_bind_args bind_args;
205
206 dev_dbg(pps->dev, "PPS_KC_BIND\n");
207
208 /* Check the capabilities */
209 if (!capable(CAP_SYS_TIME))
210 return -EPERM;
211
212 if (copy_from_user(&bind_args, uarg,
213 sizeof(struct pps_bind_args)))
214 return -EFAULT;
215
216 /* Check for supported capabilities */
217 if ((bind_args.edge & ~pps->info.mode) != 0) {
218 dev_err(pps->dev, "unsupported capabilities (%x)\n",
219 bind_args.edge);
220 return -EINVAL;
221 }
222
223 /* Validate parameters roughly */
224 if (bind_args.tsformat != PPS_TSFMT_TSPEC ||
225 (bind_args.edge & ~PPS_CAPTUREBOTH) != 0 ||
226 bind_args.consumer != PPS_KC_HARDPPS) {
227 dev_err(pps->dev, "invalid kernel consumer bind"
228 " parameters (%x)\n", bind_args.edge);
229 return -EINVAL;
230 }
231
232 err = pps_kc_bind(pps, &bind_args);
233 if (err < 0)
234 return err;
235
236 break;
237 }
238 default:
239 return -ENOTTY;
240 }
241
242 return 0;
243}
244
245static int pps_cdev_open(struct inode *inode, struct file *file)
246{
247 struct pps_device *pps = container_of(inode->i_cdev,
248 struct pps_device, cdev);
249 file->private_data = pps;
250
251 return 0;
252}
253
254static int pps_cdev_release(struct inode *inode, struct file *file)
255{
256 return 0;
257}
258
259/*
260 * Char device stuff
261 */
262
263static const struct file_operations pps_cdev_fops = {
264 .owner = THIS_MODULE,
265 .llseek = no_llseek,
266 .poll = pps_cdev_poll,
267 .fasync = pps_cdev_fasync,
268 .unlocked_ioctl = pps_cdev_ioctl,
269 .open = pps_cdev_open,
270 .release = pps_cdev_release,
271};
272
273static void pps_device_destruct(struct device *dev)
274{
275 struct pps_device *pps = dev_get_drvdata(dev);
276
277 /* release id here to protect others from using it while it's
278 * still in use */
279 mutex_lock(&pps_idr_lock);
280 idr_remove(&pps_idr, pps->id);
281 mutex_unlock(&pps_idr_lock);
282
283 kfree(dev);
284 kfree(pps);
285}
286
287int pps_register_cdev(struct pps_device *pps)
288{
289 int err;
290 dev_t devt;
291
292 mutex_lock(&pps_idr_lock);
293 /* Get new ID for the new PPS source */
294 if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
295 mutex_unlock(&pps_idr_lock);
296 return -ENOMEM;
297 }
298
299 /* Now really allocate the PPS source.
300 * After idr_get_new() calling the new source will be freely available
301 * into the kernel.
302 */
303 err = idr_get_new(&pps_idr, pps, &pps->id);
304 mutex_unlock(&pps_idr_lock);
305
306 if (err < 0)
307 return err;
308
309 pps->id &= MAX_IDR_MASK;
310 if (pps->id >= PPS_MAX_SOURCES) {
311 pr_err("%s: too many PPS sources in the system\n",
312 pps->info.name);
313 err = -EBUSY;
314 goto free_idr;
315 }
316
317 devt = MKDEV(MAJOR(pps_devt), pps->id);
318
319 cdev_init(&pps->cdev, &pps_cdev_fops);
320 pps->cdev.owner = pps->info.owner;
321
322 err = cdev_add(&pps->cdev, devt, 1);
323 if (err) {
324 pr_err("%s: failed to add char device %d:%d\n",
325 pps->info.name, MAJOR(pps_devt), pps->id);
326 goto free_idr;
327 }
328 pps->dev = device_create(pps_class, pps->info.dev, devt, pps,
329 "pps%d", pps->id);
330 if (IS_ERR(pps->dev)) {
331 err = PTR_ERR(pps->dev);
332 goto del_cdev;
333 }
334
335 pps->dev->release = pps_device_destruct;
336
337 pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
338 MAJOR(pps_devt), pps->id);
339
340 return 0;
341
342del_cdev:
343 cdev_del(&pps->cdev);
344
345free_idr:
346 mutex_lock(&pps_idr_lock);
347 idr_remove(&pps_idr, pps->id);
348 mutex_unlock(&pps_idr_lock);
349
350 return err;
351}
352
353void pps_unregister_cdev(struct pps_device *pps)
354{
355 device_destroy(pps_class, pps->dev->devt);
356 cdev_del(&pps->cdev);
357}
358
359/*
360 * Module stuff
361 */
362
363static void __exit pps_exit(void)
364{
365 class_destroy(pps_class);
366 unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
367}
368
369static int __init pps_init(void)
370{
371 int err;
372
373 pps_class = class_create(THIS_MODULE, "pps");
374 if (IS_ERR(pps_class)) {
375 pr_err("failed to allocate class\n");
376 return PTR_ERR(pps_class);
377 }
378 pps_class->dev_attrs = pps_attrs;
379
380 err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
381 if (err < 0) {
382 pr_err("failed to allocate char device region\n");
383 goto remove_class;
384 }
385
386 pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);
387 pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "
388 "<[email protected]>\n", PPS_VERSION);
389
390 return 0;
391
392remove_class:
393 class_destroy(pps_class);
394
395 return err;
396}
397
398subsys_initcall(pps_init);
399module_exit(pps_exit);
400
401MODULE_AUTHOR("Rodolfo Giometti <[email protected]>");
402MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
403MODULE_LICENSE("GPL");