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d94ba80e RC |
1 | /* |
2 | * PTP 1588 clock support | |
3 | * | |
4 | * Copyright (C) 2010 OMICRON electronics GmbH | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | #include <linux/bitops.h> | |
21 | #include <linux/device.h> | |
22 | #include <linux/err.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/posix-clock.h> | |
27 | #include <linux/pps_kernel.h> | |
28 | #include <linux/slab.h> | |
29 | #include <linux/syscalls.h> | |
30 | #include <linux/uaccess.h> | |
31 | ||
32 | #include "ptp_private.h" | |
33 | ||
34 | #define PTP_MAX_ALARMS 4 | |
35 | #define PTP_MAX_CLOCKS 8 | |
36 | #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT) | |
37 | #define PTP_PPS_EVENT PPS_CAPTUREASSERT | |
38 | #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC) | |
39 | ||
40 | /* private globals */ | |
41 | ||
42 | static dev_t ptp_devt; | |
43 | static struct class *ptp_class; | |
44 | ||
45 | static DECLARE_BITMAP(ptp_clocks_map, PTP_MAX_CLOCKS); | |
46 | static DEFINE_MUTEX(ptp_clocks_mutex); /* protects 'ptp_clocks_map' */ | |
47 | ||
48 | /* time stamp event queue operations */ | |
49 | ||
50 | static inline int queue_free(struct timestamp_event_queue *q) | |
51 | { | |
52 | return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1; | |
53 | } | |
54 | ||
55 | static void enqueue_external_timestamp(struct timestamp_event_queue *queue, | |
56 | struct ptp_clock_event *src) | |
57 | { | |
58 | struct ptp_extts_event *dst; | |
59 | unsigned long flags; | |
60 | s64 seconds; | |
61 | u32 remainder; | |
62 | ||
63 | seconds = div_u64_rem(src->timestamp, 1000000000, &remainder); | |
64 | ||
65 | spin_lock_irqsave(&queue->lock, flags); | |
66 | ||
67 | dst = &queue->buf[queue->tail]; | |
68 | dst->index = src->index; | |
69 | dst->t.sec = seconds; | |
70 | dst->t.nsec = remainder; | |
71 | ||
72 | if (!queue_free(queue)) | |
73 | queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS; | |
74 | ||
75 | queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS; | |
76 | ||
77 | spin_unlock_irqrestore(&queue->lock, flags); | |
78 | } | |
79 | ||
80 | static s32 scaled_ppm_to_ppb(long ppm) | |
81 | { | |
82 | /* | |
83 | * The 'freq' field in the 'struct timex' is in parts per | |
84 | * million, but with a 16 bit binary fractional field. | |
85 | * | |
86 | * We want to calculate | |
87 | * | |
88 | * ppb = scaled_ppm * 1000 / 2^16 | |
89 | * | |
90 | * which simplifies to | |
91 | * | |
92 | * ppb = scaled_ppm * 125 / 2^13 | |
93 | */ | |
94 | s64 ppb = 1 + ppm; | |
95 | ppb *= 125; | |
96 | ppb >>= 13; | |
97 | return (s32) ppb; | |
98 | } | |
99 | ||
100 | /* posix clock implementation */ | |
101 | ||
102 | static int ptp_clock_getres(struct posix_clock *pc, struct timespec *tp) | |
103 | { | |
d68fb11c TG |
104 | tp->tv_sec = 0; |
105 | tp->tv_nsec = 1; | |
106 | return 0; | |
d94ba80e RC |
107 | } |
108 | ||
109 | static int ptp_clock_settime(struct posix_clock *pc, const struct timespec *tp) | |
110 | { | |
111 | struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); | |
112 | return ptp->info->settime(ptp->info, tp); | |
113 | } | |
114 | ||
115 | static int ptp_clock_gettime(struct posix_clock *pc, struct timespec *tp) | |
116 | { | |
117 | struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); | |
118 | return ptp->info->gettime(ptp->info, tp); | |
119 | } | |
120 | ||
121 | static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx) | |
122 | { | |
123 | struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); | |
124 | struct ptp_clock_info *ops; | |
125 | int err = -EOPNOTSUPP; | |
126 | ||
127 | ops = ptp->info; | |
128 | ||
129 | if (tx->modes & ADJ_SETOFFSET) { | |
130 | struct timespec ts; | |
131 | ktime_t kt; | |
132 | s64 delta; | |
133 | ||
134 | ts.tv_sec = tx->time.tv_sec; | |
135 | ts.tv_nsec = tx->time.tv_usec; | |
136 | ||
137 | if (!(tx->modes & ADJ_NANO)) | |
138 | ts.tv_nsec *= 1000; | |
139 | ||
140 | if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC) | |
141 | return -EINVAL; | |
142 | ||
143 | kt = timespec_to_ktime(ts); | |
144 | delta = ktime_to_ns(kt); | |
145 | err = ops->adjtime(ops, delta); | |
146 | ||
147 | } else if (tx->modes & ADJ_FREQUENCY) { | |
148 | ||
149 | err = ops->adjfreq(ops, scaled_ppm_to_ppb(tx->freq)); | |
150 | } | |
151 | ||
152 | return err; | |
153 | } | |
154 | ||
155 | static struct posix_clock_operations ptp_clock_ops = { | |
156 | .owner = THIS_MODULE, | |
157 | .clock_adjtime = ptp_clock_adjtime, | |
158 | .clock_gettime = ptp_clock_gettime, | |
159 | .clock_getres = ptp_clock_getres, | |
160 | .clock_settime = ptp_clock_settime, | |
161 | .ioctl = ptp_ioctl, | |
162 | .open = ptp_open, | |
163 | .poll = ptp_poll, | |
164 | .read = ptp_read, | |
165 | }; | |
166 | ||
167 | static void delete_ptp_clock(struct posix_clock *pc) | |
168 | { | |
169 | struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); | |
170 | ||
171 | mutex_destroy(&ptp->tsevq_mux); | |
172 | ||
173 | /* Remove the clock from the bit map. */ | |
174 | mutex_lock(&ptp_clocks_mutex); | |
175 | clear_bit(ptp->index, ptp_clocks_map); | |
176 | mutex_unlock(&ptp_clocks_mutex); | |
177 | ||
178 | kfree(ptp); | |
179 | } | |
180 | ||
181 | /* public interface */ | |
182 | ||
183 | struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info) | |
184 | { | |
185 | struct ptp_clock *ptp; | |
186 | int err = 0, index, major = MAJOR(ptp_devt); | |
187 | ||
188 | if (info->n_alarm > PTP_MAX_ALARMS) | |
189 | return ERR_PTR(-EINVAL); | |
190 | ||
191 | /* Find a free clock slot and reserve it. */ | |
192 | err = -EBUSY; | |
193 | mutex_lock(&ptp_clocks_mutex); | |
194 | index = find_first_zero_bit(ptp_clocks_map, PTP_MAX_CLOCKS); | |
195 | if (index < PTP_MAX_CLOCKS) | |
196 | set_bit(index, ptp_clocks_map); | |
197 | else | |
198 | goto no_slot; | |
199 | ||
200 | /* Initialize a clock structure. */ | |
201 | err = -ENOMEM; | |
202 | ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL); | |
203 | if (ptp == NULL) | |
204 | goto no_memory; | |
205 | ||
206 | ptp->clock.ops = ptp_clock_ops; | |
207 | ptp->clock.release = delete_ptp_clock; | |
208 | ptp->info = info; | |
209 | ptp->devid = MKDEV(major, index); | |
210 | ptp->index = index; | |
211 | spin_lock_init(&ptp->tsevq.lock); | |
212 | mutex_init(&ptp->tsevq_mux); | |
213 | init_waitqueue_head(&ptp->tsev_wq); | |
214 | ||
215 | /* Create a new device in our class. */ | |
216 | ptp->dev = device_create(ptp_class, NULL, ptp->devid, ptp, | |
217 | "ptp%d", ptp->index); | |
218 | if (IS_ERR(ptp->dev)) | |
219 | goto no_device; | |
220 | ||
221 | dev_set_drvdata(ptp->dev, ptp); | |
222 | ||
223 | err = ptp_populate_sysfs(ptp); | |
224 | if (err) | |
225 | goto no_sysfs; | |
226 | ||
227 | /* Register a new PPS source. */ | |
228 | if (info->pps) { | |
229 | struct pps_source_info pps; | |
230 | memset(&pps, 0, sizeof(pps)); | |
231 | snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index); | |
232 | pps.mode = PTP_PPS_MODE; | |
233 | pps.owner = info->owner; | |
234 | ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS); | |
235 | if (!ptp->pps_source) { | |
236 | pr_err("failed to register pps source\n"); | |
237 | goto no_pps; | |
238 | } | |
239 | } | |
240 | ||
241 | /* Create a posix clock. */ | |
242 | err = posix_clock_register(&ptp->clock, ptp->devid); | |
243 | if (err) { | |
244 | pr_err("failed to create posix clock\n"); | |
245 | goto no_clock; | |
246 | } | |
247 | ||
248 | mutex_unlock(&ptp_clocks_mutex); | |
249 | return ptp; | |
250 | ||
251 | no_clock: | |
252 | if (ptp->pps_source) | |
253 | pps_unregister_source(ptp->pps_source); | |
254 | no_pps: | |
255 | ptp_cleanup_sysfs(ptp); | |
256 | no_sysfs: | |
257 | device_destroy(ptp_class, ptp->devid); | |
258 | no_device: | |
259 | mutex_destroy(&ptp->tsevq_mux); | |
260 | kfree(ptp); | |
261 | no_memory: | |
262 | clear_bit(index, ptp_clocks_map); | |
263 | no_slot: | |
264 | mutex_unlock(&ptp_clocks_mutex); | |
265 | return ERR_PTR(err); | |
266 | } | |
267 | EXPORT_SYMBOL(ptp_clock_register); | |
268 | ||
269 | int ptp_clock_unregister(struct ptp_clock *ptp) | |
270 | { | |
271 | ptp->defunct = 1; | |
272 | wake_up_interruptible(&ptp->tsev_wq); | |
273 | ||
274 | /* Release the clock's resources. */ | |
275 | if (ptp->pps_source) | |
276 | pps_unregister_source(ptp->pps_source); | |
277 | ptp_cleanup_sysfs(ptp); | |
278 | device_destroy(ptp_class, ptp->devid); | |
279 | ||
280 | posix_clock_unregister(&ptp->clock); | |
281 | return 0; | |
282 | } | |
283 | EXPORT_SYMBOL(ptp_clock_unregister); | |
284 | ||
285 | void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) | |
286 | { | |
287 | struct pps_event_time evt; | |
288 | ||
289 | switch (event->type) { | |
290 | ||
291 | case PTP_CLOCK_ALARM: | |
292 | break; | |
293 | ||
294 | case PTP_CLOCK_EXTTS: | |
295 | enqueue_external_timestamp(&ptp->tsevq, event); | |
296 | wake_up_interruptible(&ptp->tsev_wq); | |
297 | break; | |
298 | ||
299 | case PTP_CLOCK_PPS: | |
300 | pps_get_ts(&evt); | |
301 | pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL); | |
302 | break; | |
303 | } | |
304 | } | |
305 | EXPORT_SYMBOL(ptp_clock_event); | |
306 | ||
307 | /* module operations */ | |
308 | ||
309 | static void __exit ptp_exit(void) | |
310 | { | |
311 | class_destroy(ptp_class); | |
312 | unregister_chrdev_region(ptp_devt, PTP_MAX_CLOCKS); | |
313 | } | |
314 | ||
315 | static int __init ptp_init(void) | |
316 | { | |
317 | int err; | |
318 | ||
319 | ptp_class = class_create(THIS_MODULE, "ptp"); | |
320 | if (IS_ERR(ptp_class)) { | |
321 | pr_err("ptp: failed to allocate class\n"); | |
322 | return PTR_ERR(ptp_class); | |
323 | } | |
324 | ||
325 | err = alloc_chrdev_region(&ptp_devt, 0, PTP_MAX_CLOCKS, "ptp"); | |
326 | if (err < 0) { | |
327 | pr_err("ptp: failed to allocate device region\n"); | |
328 | goto no_region; | |
329 | } | |
330 | ||
331 | ptp_class->dev_attrs = ptp_dev_attrs; | |
332 | pr_info("PTP clock support registered\n"); | |
333 | return 0; | |
334 | ||
335 | no_region: | |
336 | class_destroy(ptp_class); | |
337 | return err; | |
338 | } | |
339 | ||
340 | subsys_initcall(ptp_init); | |
341 | module_exit(ptp_exit); | |
342 | ||
c2ec3ff6 | 343 | MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>"); |
d94ba80e RC |
344 | MODULE_DESCRIPTION("PTP clocks support"); |
345 | MODULE_LICENSE("GPL"); |