1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * PTP 1588 clock support
4 *
5 * Copyright (C) 2010 OMICRON electronics GmbH
6 */
7
8#ifndef _PTP_CLOCK_KERNEL_H_
9#define _PTP_CLOCK_KERNEL_H_
10
11#include <linux/device.h>
12#include <linux/pps_kernel.h>
13#include <linux/ptp_clock.h>
14#include <linux/timecounter.h>
15#include <linux/skbuff.h>
16
17#define PTP_CLOCK_NAME_LEN 32
18/**
19 * struct ptp_clock_request - request PTP clock event
20 *
21 * @type: The type of the request.
22 * EXTTS: Configure external trigger timestamping
23 * PEROUT: Configure periodic output signal (e.g. PPS)
24 * PPS: trigger internal PPS event for input
25 * into kernel PPS subsystem
26 * @extts: describes configuration for external trigger timestamping.
27 * This is only valid when event == PTP_CLK_REQ_EXTTS.
28 * @perout: describes configuration for periodic output.
29 * This is only valid when event == PTP_CLK_REQ_PEROUT.
30 */
31
32struct ptp_clock_request {
33 enum {
34 PTP_CLK_REQ_EXTTS,
35 PTP_CLK_REQ_PEROUT,
36 PTP_CLK_REQ_PPS,
37 } type;
38 union {
39 struct ptp_extts_request extts;
40 struct ptp_perout_request perout;
41 };
42};
43
44struct system_device_crosststamp;
45
46/**
47 * struct ptp_system_timestamp - system time corresponding to a PHC timestamp
48 * @pre_ts: system timestamp before capturing PHC
49 * @post_ts: system timestamp after capturing PHC
50 */
51struct ptp_system_timestamp {
52 struct timespec64 pre_ts;
53 struct timespec64 post_ts;
54};
55
56/**
57 * struct ptp_clock_info - describes a PTP hardware clock
58 *
59 * @owner: The clock driver should set to THIS_MODULE.
60 * @name: A short "friendly name" to identify the clock and to
61 * help distinguish PHY based devices from MAC based ones.
62 * The string is not meant to be a unique id.
63 * @max_adj: The maximum possible frequency adjustment, in parts per billon.
64 * @n_alarm: The number of programmable alarms.
65 * @n_ext_ts: The number of external time stamp channels.
66 * @n_per_out: The number of programmable periodic signals.
67 * @n_pins: The number of programmable pins.
68 * @pps: Indicates whether the clock supports a PPS callback.
69 * @pin_config: Array of length 'n_pins'. If the number of
70 * programmable pins is nonzero, then drivers must
71 * allocate and initialize this array.
72 *
73 * clock operations
74 *
75 * @adjfine: Adjusts the frequency of the hardware clock.
76 * parameter scaled_ppm: Desired frequency offset from
77 * nominal frequency in parts per million, but with a
78 * 16 bit binary fractional field.
79 *
80 * @adjphase: Indicates that the PHC should use an internal servo
81 * algorithm to correct the provided phase offset.
82 * parameter delta: PHC servo phase adjustment target
83 * in nanoseconds.
84 *
85 * @getmaxphase: Advertises maximum offset that can be provided
86 * to the hardware clock's phase control functionality
87 * through adjphase.
88 *
89 * @adjtime: Shifts the time of the hardware clock.
90 * parameter delta: Desired change in nanoseconds.
91 *
92 * @gettime64: Reads the current time from the hardware clock.
93 * This method is deprecated. New drivers should implement
94 * the @gettimex64 method instead.
95 * parameter ts: Holds the result.
96 *
97 * @gettimex64: Reads the current time from the hardware clock and optionally
98 * also the system clock.
99 * parameter ts: Holds the PHC timestamp.
100 * parameter sts: If not NULL, it holds a pair of timestamps from
101 * the system clock. The first reading is made right before
102 * reading the lowest bits of the PHC timestamp and the second
103 * reading immediately follows that.
104 *
105 * @getcrosststamp: Reads the current time from the hardware clock and
106 * system clock simultaneously.
107 * parameter cts: Contains timestamp (device,system) pair,
108 * where system time is realtime and monotonic.
109 *
110 * @settime64: Set the current time on the hardware clock.
111 * parameter ts: Time value to set.
112 *
113 * @getcycles64: Reads the current free running cycle counter from the hardware
114 * clock.
115 * If @getcycles64 and @getcyclesx64 are not supported, then
116 * @gettime64 or @gettimex64 will be used as default
117 * implementation.
118 * parameter ts: Holds the result.
119 *
120 * @getcyclesx64: Reads the current free running cycle counter from the
121 * hardware clock and optionally also the system clock.
122 * If @getcycles64 and @getcyclesx64 are not supported, then
123 * @gettimex64 will be used as default implementation if
124 * available.
125 * parameter ts: Holds the PHC timestamp.
126 * parameter sts: If not NULL, it holds a pair of timestamps
127 * from the system clock. The first reading is made right before
128 * reading the lowest bits of the PHC timestamp and the second
129 * reading immediately follows that.
130 *
131 * @getcrosscycles: Reads the current free running cycle counter from the
132 * hardware clock and system clock simultaneously.
133 * If @getcycles64 and @getcyclesx64 are not supported, then
134 * @getcrosststamp will be used as default implementation if
135 * available.
136 * parameter cts: Contains timestamp (device,system) pair,
137 * where system time is realtime and monotonic.
138 *
139 * @enable: Request driver to enable or disable an ancillary feature.
140 * parameter request: Desired resource to enable or disable.
141 * parameter on: Caller passes one to enable or zero to disable.
142 *
143 * @verify: Confirm that a pin can perform a given function. The PTP
144 * Hardware Clock subsystem maintains the 'pin_config'
145 * array on behalf of the drivers, but the PHC subsystem
146 * assumes that every pin can perform every function. This
147 * hook gives drivers a way of telling the core about
148 * limitations on specific pins. This function must return
149 * zero if the function can be assigned to this pin, and
150 * nonzero otherwise.
151 * parameter pin: index of the pin in question.
152 * parameter func: the desired function to use.
153 * parameter chan: the function channel index to use.
154 *
155 * @do_aux_work: Request driver to perform auxiliary (periodic) operations
156 * Driver should return delay of the next auxiliary work
157 * scheduling time (>=0) or negative value in case further
158 * scheduling is not required.
159 *
160 * Drivers should embed their ptp_clock_info within a private
161 * structure, obtaining a reference to it using container_of().
162 *
163 * The callbacks must all return zero on success, non-zero otherwise.
164 */
165
166struct ptp_clock_info {
167 struct module *owner;
168 char name[PTP_CLOCK_NAME_LEN];
169 s32 max_adj;
170 int n_alarm;
171 int n_ext_ts;
172 int n_per_out;
173 int n_pins;
174 int pps;
175 struct ptp_pin_desc *pin_config;
176 int (*adjfine)(struct ptp_clock_info *ptp, long scaled_ppm);
177 int (*adjphase)(struct ptp_clock_info *ptp, s32 phase);
178 s32 (*getmaxphase)(struct ptp_clock_info *ptp);
179 int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
180 int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
181 int (*gettimex64)(struct ptp_clock_info *ptp, struct timespec64 *ts,
182 struct ptp_system_timestamp *sts);
183 int (*getcrosststamp)(struct ptp_clock_info *ptp,
184 struct system_device_crosststamp *cts);
185 int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts);
186 int (*getcycles64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
187 int (*getcyclesx64)(struct ptp_clock_info *ptp, struct timespec64 *ts,
188 struct ptp_system_timestamp *sts);
189 int (*getcrosscycles)(struct ptp_clock_info *ptp,
190 struct system_device_crosststamp *cts);
191 int (*enable)(struct ptp_clock_info *ptp,
192 struct ptp_clock_request *request, int on);
193 int (*verify)(struct ptp_clock_info *ptp, unsigned int pin,
194 enum ptp_pin_function func, unsigned int chan);
195 long (*do_aux_work)(struct ptp_clock_info *ptp);
196};
197
198struct ptp_clock;
199
200enum ptp_clock_events {
201 PTP_CLOCK_ALARM,
202 PTP_CLOCK_EXTTS,
203 PTP_CLOCK_PPS,
204 PTP_CLOCK_PPSUSR,
205};
206
207/**
208 * struct ptp_clock_event - decribes a PTP hardware clock event
209 *
210 * @type: One of the ptp_clock_events enumeration values.
211 * @index: Identifies the source of the event.
212 * @timestamp: When the event occurred (%PTP_CLOCK_EXTTS only).
213 * @pps_times: When the event occurred (%PTP_CLOCK_PPSUSR only).
214 */
215
216struct ptp_clock_event {
217 int type;
218 int index;
219 union {
220 u64 timestamp;
221 struct pps_event_time pps_times;
222 };
223};
224
225/**
226 * scaled_ppm_to_ppb() - convert scaled ppm to ppb
227 *
228 * @ppm: Parts per million, but with a 16 bit binary fractional field
229 */
230static inline long scaled_ppm_to_ppb(long ppm)
231{
232 /*
233 * The 'freq' field in the 'struct timex' is in parts per
234 * million, but with a 16 bit binary fractional field.
235 *
236 * We want to calculate
237 *
238 * ppb = scaled_ppm * 1000 / 2^16
239 *
240 * which simplifies to
241 *
242 * ppb = scaled_ppm * 125 / 2^13
243 */
244 s64 ppb = 1 + ppm;
245
246 ppb *= 125;
247 ppb >>= 13;
248 return (long)ppb;
249}
250
251/**
252 * diff_by_scaled_ppm - Calculate difference using scaled ppm
253 * @base: the base increment value to adjust
254 * @scaled_ppm: scaled parts per million to adjust by
255 * @diff: on return, the absolute value of calculated diff
256 *
257 * Calculate the difference to adjust the base increment using scaled parts
258 * per million.
259 *
260 * Use mul_u64_u64_div_u64 to perform the difference calculation in avoid
261 * possible overflow.
262 *
263 * Returns: true if scaled_ppm is negative, false otherwise
264 */
265static inline bool diff_by_scaled_ppm(u64 base, long scaled_ppm, u64 *diff)
266{
267 bool negative = false;
268
269 if (scaled_ppm < 0) {
270 negative = true;
271 scaled_ppm = -scaled_ppm;
272 }
273
274 *diff = mul_u64_u64_div_u64(a: base, mul: (u64)scaled_ppm, div: 1000000ULL << 16);
275
276 return negative;
277}
278
279/**
280 * adjust_by_scaled_ppm - Adjust a base increment by scaled parts per million
281 * @base: the base increment value to adjust
282 * @scaled_ppm: scaled parts per million frequency adjustment
283 *
284 * Helper function which calculates a new increment value based on the
285 * requested scaled parts per million adjustment.
286 */
287static inline u64 adjust_by_scaled_ppm(u64 base, long scaled_ppm)
288{
289 u64 diff;
290
291 if (diff_by_scaled_ppm(base, scaled_ppm, diff: &diff))
292 return base - diff;
293
294 return base + diff;
295}
296
297#if IS_ENABLED(CONFIG_PTP_1588_CLOCK)
298
299/**
300 * ptp_clock_register() - register a PTP hardware clock driver
301 *
302 * @info: Structure describing the new clock.
303 * @parent: Pointer to the parent device of the new clock.
304 *
305 * Returns a valid pointer on success or PTR_ERR on failure. If PHC
306 * support is missing at the configuration level, this function
307 * returns NULL, and drivers are expected to gracefully handle that
308 * case separately.
309 */
310
311extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
312 struct device *parent);
313
314/**
315 * ptp_clock_unregister() - unregister a PTP hardware clock driver
316 *
317 * @ptp: The clock to remove from service.
318 */
319
320extern int ptp_clock_unregister(struct ptp_clock *ptp);
321
322/**
323 * ptp_clock_event() - notify the PTP layer about an event
324 *
325 * @ptp: The clock obtained from ptp_clock_register().
326 * @event: Message structure describing the event.
327 */
328
329extern void ptp_clock_event(struct ptp_clock *ptp,
330 struct ptp_clock_event *event);
331
332/**
333 * ptp_clock_index() - obtain the device index of a PTP clock
334 *
335 * @ptp: The clock obtained from ptp_clock_register().
336 */
337
338extern int ptp_clock_index(struct ptp_clock *ptp);
339
340/**
341 * ptp_find_pin() - obtain the pin index of a given auxiliary function
342 *
343 * The caller must hold ptp_clock::pincfg_mux. Drivers do not have
344 * access to that mutex as ptp_clock is an opaque type. However, the
345 * core code acquires the mutex before invoking the driver's
346 * ptp_clock_info::enable() callback, and so drivers may call this
347 * function from that context.
348 *
349 * @ptp: The clock obtained from ptp_clock_register().
350 * @func: One of the ptp_pin_function enumerated values.
351 * @chan: The particular functional channel to find.
352 * Return: Pin index in the range of zero to ptp_clock_caps.n_pins - 1,
353 * or -1 if the auxiliary function cannot be found.
354 */
355
356int ptp_find_pin(struct ptp_clock *ptp,
357 enum ptp_pin_function func, unsigned int chan);
358
359/**
360 * ptp_find_pin_unlocked() - wrapper for ptp_find_pin()
361 *
362 * This function acquires the ptp_clock::pincfg_mux mutex before
363 * invoking ptp_find_pin(). Instead of using this function, drivers
364 * should most likely call ptp_find_pin() directly from their
365 * ptp_clock_info::enable() method.
366 *
367* @ptp: The clock obtained from ptp_clock_register().
368* @func: One of the ptp_pin_function enumerated values.
369* @chan: The particular functional channel to find.
370* Return: Pin index in the range of zero to ptp_clock_caps.n_pins - 1,
371* or -1 if the auxiliary function cannot be found.
372 */
373
374int ptp_find_pin_unlocked(struct ptp_clock *ptp,
375 enum ptp_pin_function func, unsigned int chan);
376
377/**
378 * ptp_schedule_worker() - schedule ptp auxiliary work
379 *
380 * @ptp: The clock obtained from ptp_clock_register().
381 * @delay: number of jiffies to wait before queuing
382 * See kthread_queue_delayed_work() for more info.
383 */
384
385int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay);
386
387/**
388 * ptp_cancel_worker_sync() - cancel ptp auxiliary clock
389 *
390 * @ptp: The clock obtained from ptp_clock_register().
391 */
392void ptp_cancel_worker_sync(struct ptp_clock *ptp);
393
394#else
395static inline struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
396 struct device *parent)
397{ return NULL; }
398static inline int ptp_clock_unregister(struct ptp_clock *ptp)
399{ return 0; }
400static inline void ptp_clock_event(struct ptp_clock *ptp,
401 struct ptp_clock_event *event)
402{ }
403static inline int ptp_clock_index(struct ptp_clock *ptp)
404{ return -1; }
405static inline int ptp_find_pin(struct ptp_clock *ptp,
406 enum ptp_pin_function func, unsigned int chan)
407{ return -1; }
408static inline int ptp_find_pin_unlocked(struct ptp_clock *ptp,
409 enum ptp_pin_function func,
410 unsigned int chan)
411{ return -1; }
412static inline int ptp_schedule_worker(struct ptp_clock *ptp,
413 unsigned long delay)
414{ return -EOPNOTSUPP; }
415static inline void ptp_cancel_worker_sync(struct ptp_clock *ptp)
416{ }
417#endif
418
419#if IS_BUILTIN(CONFIG_PTP_1588_CLOCK)
420/*
421 * These are called by the network core, and don't work if PTP is in
422 * a loadable module.
423 */
424
425/**
426 * ptp_get_vclocks_index() - get all vclocks index on pclock, and
427 * caller is responsible to free memory
428 * of vclock_index
429 *
430 * @pclock_index: phc index of ptp pclock.
431 * @vclock_index: pointer to pointer of vclock index.
432 *
433 * return number of vclocks.
434 */
435int ptp_get_vclocks_index(int pclock_index, int **vclock_index);
436
437/**
438 * ptp_convert_timestamp() - convert timestamp to a ptp vclock time
439 *
440 * @hwtstamp: timestamp
441 * @vclock_index: phc index of ptp vclock.
442 *
443 * Returns converted timestamp, or 0 on error.
444 */
445ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp, int vclock_index);
446#else
447static inline int ptp_get_vclocks_index(int pclock_index, int **vclock_index)
448{ return 0; }
449static inline ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp,
450 int vclock_index)
451{ return 0; }
452
453#endif
454
455static inline void ptp_read_system_prets(struct ptp_system_timestamp *sts)
456{
457 if (sts)
458 ktime_get_real_ts64(tv: &sts->pre_ts);
459}
460
461static inline void ptp_read_system_postts(struct ptp_system_timestamp *sts)
462{
463 if (sts)
464 ktime_get_real_ts64(tv: &sts->post_ts);
465}
466
467#endif
468

source code of linux/include/linux/ptp_clock_kernel.h