xref: /linux/include/linux/ptp_clock_kernel.h (revision b5bee6ced21ca98389000b7017dd41b0cc37fa50)
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 
32 struct 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 
44 struct system_device_crosststamp;
45 
46 /**
47  * struct ptp_system_timestamp - system time corresponding to a PHC timestamp
48  */
49 struct ptp_system_timestamp {
50 	struct timespec64 pre_ts;
51 	struct timespec64 post_ts;
52 };
53 
54 /**
55  * struct ptp_clock_info - describes a PTP hardware clock
56  *
57  * @owner:     The clock driver should set to THIS_MODULE.
58  * @name:      A short "friendly name" to identify the clock and to
59  *             help distinguish PHY based devices from MAC based ones.
60  *             The string is not meant to be a unique id.
61  * @max_adj:   The maximum possible frequency adjustment, in parts per billon.
62  * @n_alarm:   The number of programmable alarms.
63  * @n_ext_ts:  The number of external time stamp channels.
64  * @n_per_out: The number of programmable periodic signals.
65  * @n_pins:    The number of programmable pins.
66  * @pps:       Indicates whether the clock supports a PPS callback.
67  * @pin_config: Array of length 'n_pins'. If the number of
68  *              programmable pins is nonzero, then drivers must
69  *              allocate and initialize this array.
70  *
71  * clock operations
72  *
73  * @adjfine:  Adjusts the frequency of the hardware clock.
74  *            parameter scaled_ppm: Desired frequency offset from
75  *            nominal frequency in parts per million, but with a
76  *            16 bit binary fractional field.
77  *
78  * @adjfreq:  Adjusts the frequency of the hardware clock.
79  *            This method is deprecated.  New drivers should implement
80  *            the @adjfine method instead.
81  *            parameter delta: Desired frequency offset from nominal frequency
82  *            in parts per billion
83  *
84  * @adjphase:  Adjusts the phase offset of the hardware clock.
85  *             parameter delta: Desired change in nanoseconds.
86  *
87  * @adjtime:  Shifts the time of the hardware clock.
88  *            parameter delta: Desired change in nanoseconds.
89  *
90  * @gettime64:  Reads the current time from the hardware clock.
91  *              This method is deprecated.  New drivers should implement
92  *              the @gettimex64 method instead.
93  *              parameter ts: Holds the result.
94  *
95  * @gettimex64:  Reads the current time from the hardware clock and optionally
96  *               also the system clock.
97  *               parameter ts: Holds the PHC timestamp.
98  *               parameter sts: If not NULL, it holds a pair of timestamps from
99  *               the system clock. The first reading is made right before
100  *               reading the lowest bits of the PHC timestamp and the second
101  *               reading immediately follows that.
102  *
103  * @getcrosststamp:  Reads the current time from the hardware clock and
104  *                   system clock simultaneously.
105  *                   parameter cts: Contains timestamp (device,system) pair,
106  *                   where system time is realtime and monotonic.
107  *
108  * @settime64:  Set the current time on the hardware clock.
109  *              parameter ts: Time value to set.
110  *
111  * @getcycles64:  Reads the current free running cycle counter from the hardware
112  *                clock.
113  *                If @getcycles64 and @getcyclesx64 are not supported, then
114  *                @gettime64 or @gettimex64 will be used as default
115  *                implementation.
116  *                parameter ts: Holds the result.
117  *
118  * @getcyclesx64:  Reads the current free running cycle counter from the
119  *                 hardware clock and optionally also the system clock.
120  *                 If @getcycles64 and @getcyclesx64 are not supported, then
121  *                 @gettimex64 will be used as default implementation if
122  *                 available.
123  *                 parameter ts: Holds the PHC timestamp.
124  *                 parameter sts: If not NULL, it holds a pair of timestamps
125  *                 from the system clock. The first reading is made right before
126  *                 reading the lowest bits of the PHC timestamp and the second
127  *                 reading immediately follows that.
128  *
129  * @getcrosscycles:  Reads the current free running cycle counter from the
130  *                   hardware clock and system clock simultaneously.
131  *                   If @getcycles64 and @getcyclesx64 are not supported, then
132  *                   @getcrosststamp will be used as default implementation if
133  *                   available.
134  *                   parameter cts: Contains timestamp (device,system) pair,
135  *                   where system time is realtime and monotonic.
136  *
137  * @enable:   Request driver to enable or disable an ancillary feature.
138  *            parameter request: Desired resource to enable or disable.
139  *            parameter on: Caller passes one to enable or zero to disable.
140  *
141  * @verify:   Confirm that a pin can perform a given function. The PTP
142  *            Hardware Clock subsystem maintains the 'pin_config'
143  *            array on behalf of the drivers, but the PHC subsystem
144  *            assumes that every pin can perform every function. This
145  *            hook gives drivers a way of telling the core about
146  *            limitations on specific pins. This function must return
147  *            zero if the function can be assigned to this pin, and
148  *            nonzero otherwise.
149  *            parameter pin: index of the pin in question.
150  *            parameter func: the desired function to use.
151  *            parameter chan: the function channel index to use.
152  *
153  * @do_aux_work:  Request driver to perform auxiliary (periodic) operations
154  *                Driver should return delay of the next auxiliary work
155  *                scheduling time (>=0) or negative value in case further
156  *                scheduling is not required.
157  *
158  * Drivers should embed their ptp_clock_info within a private
159  * structure, obtaining a reference to it using container_of().
160  *
161  * The callbacks must all return zero on success, non-zero otherwise.
162  */
163 
164 struct ptp_clock_info {
165 	struct module *owner;
166 	char name[PTP_CLOCK_NAME_LEN];
167 	s32 max_adj;
168 	int n_alarm;
169 	int n_ext_ts;
170 	int n_per_out;
171 	int n_pins;
172 	int pps;
173 	struct ptp_pin_desc *pin_config;
174 	int (*adjfine)(struct ptp_clock_info *ptp, long scaled_ppm);
175 	int (*adjfreq)(struct ptp_clock_info *ptp, s32 delta);
176 	int (*adjphase)(struct ptp_clock_info *ptp, s32 phase);
177 	int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
178 	int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
179 	int (*gettimex64)(struct ptp_clock_info *ptp, struct timespec64 *ts,
180 			  struct ptp_system_timestamp *sts);
181 	int (*getcrosststamp)(struct ptp_clock_info *ptp,
182 			      struct system_device_crosststamp *cts);
183 	int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts);
184 	int (*getcycles64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
185 	int (*getcyclesx64)(struct ptp_clock_info *ptp, struct timespec64 *ts,
186 			    struct ptp_system_timestamp *sts);
187 	int (*getcrosscycles)(struct ptp_clock_info *ptp,
188 			      struct system_device_crosststamp *cts);
189 	int (*enable)(struct ptp_clock_info *ptp,
190 		      struct ptp_clock_request *request, int on);
191 	int (*verify)(struct ptp_clock_info *ptp, unsigned int pin,
192 		      enum ptp_pin_function func, unsigned int chan);
193 	long (*do_aux_work)(struct ptp_clock_info *ptp);
194 };
195 
196 struct ptp_clock;
197 
198 enum ptp_clock_events {
199 	PTP_CLOCK_ALARM,
200 	PTP_CLOCK_EXTTS,
201 	PTP_CLOCK_PPS,
202 	PTP_CLOCK_PPSUSR,
203 };
204 
205 /**
206  * struct ptp_clock_event - decribes a PTP hardware clock event
207  *
208  * @type:  One of the ptp_clock_events enumeration values.
209  * @index: Identifies the source of the event.
210  * @timestamp: When the event occurred (%PTP_CLOCK_EXTTS only).
211  * @pps_times: When the event occurred (%PTP_CLOCK_PPSUSR only).
212  */
213 
214 struct ptp_clock_event {
215 	int type;
216 	int index;
217 	union {
218 		u64 timestamp;
219 		struct pps_event_time pps_times;
220 	};
221 };
222 
223 /**
224  * scaled_ppm_to_ppb() - convert scaled ppm to ppb
225  *
226  * @ppm:    Parts per million, but with a 16 bit binary fractional field
227  */
228 static inline long scaled_ppm_to_ppb(long ppm)
229 {
230 	/*
231 	 * The 'freq' field in the 'struct timex' is in parts per
232 	 * million, but with a 16 bit binary fractional field.
233 	 *
234 	 * We want to calculate
235 	 *
236 	 *    ppb = scaled_ppm * 1000 / 2^16
237 	 *
238 	 * which simplifies to
239 	 *
240 	 *    ppb = scaled_ppm * 125 / 2^13
241 	 */
242 	s64 ppb = 1 + ppm;
243 
244 	ppb *= 125;
245 	ppb >>= 13;
246 	return (long)ppb;
247 }
248 
249 #if IS_ENABLED(CONFIG_PTP_1588_CLOCK)
250 
251 /**
252  * ptp_clock_register() - register a PTP hardware clock driver
253  *
254  * @info:   Structure describing the new clock.
255  * @parent: Pointer to the parent device of the new clock.
256  *
257  * Returns a valid pointer on success or PTR_ERR on failure.  If PHC
258  * support is missing at the configuration level, this function
259  * returns NULL, and drivers are expected to gracefully handle that
260  * case separately.
261  */
262 
263 extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
264 					    struct device *parent);
265 
266 /**
267  * ptp_clock_unregister() - unregister a PTP hardware clock driver
268  *
269  * @ptp:  The clock to remove from service.
270  */
271 
272 extern int ptp_clock_unregister(struct ptp_clock *ptp);
273 
274 /**
275  * ptp_clock_event() - notify the PTP layer about an event
276  *
277  * @ptp:    The clock obtained from ptp_clock_register().
278  * @event:  Message structure describing the event.
279  */
280 
281 extern void ptp_clock_event(struct ptp_clock *ptp,
282 			    struct ptp_clock_event *event);
283 
284 /**
285  * ptp_clock_index() - obtain the device index of a PTP clock
286  *
287  * @ptp:    The clock obtained from ptp_clock_register().
288  */
289 
290 extern int ptp_clock_index(struct ptp_clock *ptp);
291 
292 /**
293  * ptp_find_pin() - obtain the pin index of a given auxiliary function
294  *
295  * The caller must hold ptp_clock::pincfg_mux.  Drivers do not have
296  * access to that mutex as ptp_clock is an opaque type.  However, the
297  * core code acquires the mutex before invoking the driver's
298  * ptp_clock_info::enable() callback, and so drivers may call this
299  * function from that context.
300  *
301  * @ptp:    The clock obtained from ptp_clock_register().
302  * @func:   One of the ptp_pin_function enumerated values.
303  * @chan:   The particular functional channel to find.
304  * Return:  Pin index in the range of zero to ptp_clock_caps.n_pins - 1,
305  *          or -1 if the auxiliary function cannot be found.
306  */
307 
308 int ptp_find_pin(struct ptp_clock *ptp,
309 		 enum ptp_pin_function func, unsigned int chan);
310 
311 /**
312  * ptp_find_pin_unlocked() - wrapper for ptp_find_pin()
313  *
314  * This function acquires the ptp_clock::pincfg_mux mutex before
315  * invoking ptp_find_pin().  Instead of using this function, drivers
316  * should most likely call ptp_find_pin() directly from their
317  * ptp_clock_info::enable() method.
318  *
319  */
320 
321 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
322 			  enum ptp_pin_function func, unsigned int chan);
323 
324 /**
325  * ptp_schedule_worker() - schedule ptp auxiliary work
326  *
327  * @ptp:    The clock obtained from ptp_clock_register().
328  * @delay:  number of jiffies to wait before queuing
329  *          See kthread_queue_delayed_work() for more info.
330  */
331 
332 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay);
333 
334 /**
335  * ptp_cancel_worker_sync() - cancel ptp auxiliary clock
336  *
337  * @ptp:     The clock obtained from ptp_clock_register().
338  */
339 void ptp_cancel_worker_sync(struct ptp_clock *ptp);
340 
341 #else
342 static inline struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
343 						   struct device *parent)
344 { return NULL; }
345 static inline int ptp_clock_unregister(struct ptp_clock *ptp)
346 { return 0; }
347 static inline void ptp_clock_event(struct ptp_clock *ptp,
348 				   struct ptp_clock_event *event)
349 { }
350 static inline int ptp_clock_index(struct ptp_clock *ptp)
351 { return -1; }
352 static inline int ptp_find_pin(struct ptp_clock *ptp,
353 			       enum ptp_pin_function func, unsigned int chan)
354 { return -1; }
355 static inline int ptp_find_pin_unlocked(struct ptp_clock *ptp,
356 					enum ptp_pin_function func,
357 					unsigned int chan)
358 { return -1; }
359 static inline int ptp_schedule_worker(struct ptp_clock *ptp,
360 				      unsigned long delay)
361 { return -EOPNOTSUPP; }
362 static inline void ptp_cancel_worker_sync(struct ptp_clock *ptp)
363 { }
364 #endif
365 
366 #if IS_BUILTIN(CONFIG_PTP_1588_CLOCK)
367 /*
368  * These are called by the network core, and don't work if PTP is in
369  * a loadable module.
370  */
371 
372 /**
373  * ptp_get_vclocks_index() - get all vclocks index on pclock, and
374  *                           caller is responsible to free memory
375  *                           of vclock_index
376  *
377  * @pclock_index: phc index of ptp pclock.
378  * @vclock_index: pointer to pointer of vclock index.
379  *
380  * return number of vclocks.
381  */
382 int ptp_get_vclocks_index(int pclock_index, int **vclock_index);
383 
384 /**
385  * ptp_convert_timestamp() - convert timestamp to a ptp vclock time
386  *
387  * @hwtstamp:     timestamp
388  * @vclock_index: phc index of ptp vclock.
389  *
390  * Returns converted timestamp, or 0 on error.
391  */
392 ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp, int vclock_index);
393 #else
394 static inline int ptp_get_vclocks_index(int pclock_index, int **vclock_index)
395 { return 0; }
396 static inline ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp,
397 					    int vclock_index)
398 { return 0; }
399 
400 #endif
401 
402 static inline void ptp_read_system_prets(struct ptp_system_timestamp *sts)
403 {
404 	if (sts)
405 		ktime_get_real_ts64(&sts->pre_ts);
406 }
407 
408 static inline void ptp_read_system_postts(struct ptp_system_timestamp *sts)
409 {
410 	if (sts)
411 		ktime_get_real_ts64(&sts->post_ts);
412 }
413 
414 #endif
415