xref: /linux/include/linux/ptp_clock_kernel.h (revision 17b121ad0c43342bc894632f6710b894849ca372)
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  * @enable:   Request driver to enable or disable an ancillary feature.
112  *            parameter request: Desired resource to enable or disable.
113  *            parameter on: Caller passes one to enable or zero to disable.
114  *
115  * @verify:   Confirm that a pin can perform a given function. The PTP
116  *            Hardware Clock subsystem maintains the 'pin_config'
117  *            array on behalf of the drivers, but the PHC subsystem
118  *            assumes that every pin can perform every function. This
119  *            hook gives drivers a way of telling the core about
120  *            limitations on specific pins. This function must return
121  *            zero if the function can be assigned to this pin, and
122  *            nonzero otherwise.
123  *            parameter pin: index of the pin in question.
124  *            parameter func: the desired function to use.
125  *            parameter chan: the function channel index to use.
126  *
127  * @do_aux_work:  Request driver to perform auxiliary (periodic) operations
128  *                Driver should return delay of the next auxiliary work
129  *                scheduling time (>=0) or negative value in case further
130  *                scheduling is not required.
131  *
132  * Drivers should embed their ptp_clock_info within a private
133  * structure, obtaining a reference to it using container_of().
134  *
135  * The callbacks must all return zero on success, non-zero otherwise.
136  */
137 
138 struct ptp_clock_info {
139 	struct module *owner;
140 	char name[PTP_CLOCK_NAME_LEN];
141 	s32 max_adj;
142 	int n_alarm;
143 	int n_ext_ts;
144 	int n_per_out;
145 	int n_pins;
146 	int pps;
147 	struct ptp_pin_desc *pin_config;
148 	int (*adjfine)(struct ptp_clock_info *ptp, long scaled_ppm);
149 	int (*adjfreq)(struct ptp_clock_info *ptp, s32 delta);
150 	int (*adjphase)(struct ptp_clock_info *ptp, s32 phase);
151 	int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
152 	int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
153 	int (*gettimex64)(struct ptp_clock_info *ptp, struct timespec64 *ts,
154 			  struct ptp_system_timestamp *sts);
155 	int (*getcrosststamp)(struct ptp_clock_info *ptp,
156 			      struct system_device_crosststamp *cts);
157 	int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts);
158 	int (*enable)(struct ptp_clock_info *ptp,
159 		      struct ptp_clock_request *request, int on);
160 	int (*verify)(struct ptp_clock_info *ptp, unsigned int pin,
161 		      enum ptp_pin_function func, unsigned int chan);
162 	long (*do_aux_work)(struct ptp_clock_info *ptp);
163 };
164 
165 struct ptp_clock;
166 
167 enum ptp_clock_events {
168 	PTP_CLOCK_ALARM,
169 	PTP_CLOCK_EXTTS,
170 	PTP_CLOCK_PPS,
171 	PTP_CLOCK_PPSUSR,
172 };
173 
174 /**
175  * struct ptp_clock_event - decribes a PTP hardware clock event
176  *
177  * @type:  One of the ptp_clock_events enumeration values.
178  * @index: Identifies the source of the event.
179  * @timestamp: When the event occurred (%PTP_CLOCK_EXTTS only).
180  * @pps_times: When the event occurred (%PTP_CLOCK_PPSUSR only).
181  */
182 
183 struct ptp_clock_event {
184 	int type;
185 	int index;
186 	union {
187 		u64 timestamp;
188 		struct pps_event_time pps_times;
189 	};
190 };
191 
192 /**
193  * scaled_ppm_to_ppb() - convert scaled ppm to ppb
194  *
195  * @ppm:    Parts per million, but with a 16 bit binary fractional field
196  */
197 static inline long scaled_ppm_to_ppb(long ppm)
198 {
199 	/*
200 	 * The 'freq' field in the 'struct timex' is in parts per
201 	 * million, but with a 16 bit binary fractional field.
202 	 *
203 	 * We want to calculate
204 	 *
205 	 *    ppb = scaled_ppm * 1000 / 2^16
206 	 *
207 	 * which simplifies to
208 	 *
209 	 *    ppb = scaled_ppm * 125 / 2^13
210 	 */
211 	s64 ppb = 1 + ppm;
212 
213 	ppb *= 125;
214 	ppb >>= 13;
215 	return (long)ppb;
216 }
217 
218 #if IS_REACHABLE(CONFIG_PTP_1588_CLOCK)
219 
220 /**
221  * ptp_clock_register() - register a PTP hardware clock driver
222  *
223  * @info:   Structure describing the new clock.
224  * @parent: Pointer to the parent device of the new clock.
225  *
226  * Returns a valid pointer on success or PTR_ERR on failure.  If PHC
227  * support is missing at the configuration level, this function
228  * returns NULL, and drivers are expected to gracefully handle that
229  * case separately.
230  */
231 
232 extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
233 					    struct device *parent);
234 
235 /**
236  * ptp_clock_unregister() - unregister a PTP hardware clock driver
237  *
238  * @ptp:  The clock to remove from service.
239  */
240 
241 extern int ptp_clock_unregister(struct ptp_clock *ptp);
242 
243 /**
244  * ptp_clock_event() - notify the PTP layer about an event
245  *
246  * @ptp:    The clock obtained from ptp_clock_register().
247  * @event:  Message structure describing the event.
248  */
249 
250 extern void ptp_clock_event(struct ptp_clock *ptp,
251 			    struct ptp_clock_event *event);
252 
253 /**
254  * ptp_clock_index() - obtain the device index of a PTP clock
255  *
256  * @ptp:    The clock obtained from ptp_clock_register().
257  */
258 
259 extern int ptp_clock_index(struct ptp_clock *ptp);
260 
261 /**
262  * ptp_find_pin() - obtain the pin index of a given auxiliary function
263  *
264  * The caller must hold ptp_clock::pincfg_mux.  Drivers do not have
265  * access to that mutex as ptp_clock is an opaque type.  However, the
266  * core code acquires the mutex before invoking the driver's
267  * ptp_clock_info::enable() callback, and so drivers may call this
268  * function from that context.
269  *
270  * @ptp:    The clock obtained from ptp_clock_register().
271  * @func:   One of the ptp_pin_function enumerated values.
272  * @chan:   The particular functional channel to find.
273  * Return:  Pin index in the range of zero to ptp_clock_caps.n_pins - 1,
274  *          or -1 if the auxiliary function cannot be found.
275  */
276 
277 int ptp_find_pin(struct ptp_clock *ptp,
278 		 enum ptp_pin_function func, unsigned int chan);
279 
280 /**
281  * ptp_find_pin_unlocked() - wrapper for ptp_find_pin()
282  *
283  * This function acquires the ptp_clock::pincfg_mux mutex before
284  * invoking ptp_find_pin().  Instead of using this function, drivers
285  * should most likely call ptp_find_pin() directly from their
286  * ptp_clock_info::enable() method.
287  *
288  */
289 
290 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
291 			  enum ptp_pin_function func, unsigned int chan);
292 
293 /**
294  * ptp_schedule_worker() - schedule ptp auxiliary work
295  *
296  * @ptp:    The clock obtained from ptp_clock_register().
297  * @delay:  number of jiffies to wait before queuing
298  *          See kthread_queue_delayed_work() for more info.
299  */
300 
301 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay);
302 
303 /**
304  * ptp_cancel_worker_sync() - cancel ptp auxiliary clock
305  *
306  * @ptp:     The clock obtained from ptp_clock_register().
307  */
308 void ptp_cancel_worker_sync(struct ptp_clock *ptp);
309 
310 /**
311  * ptp_get_vclocks_index() - get all vclocks index on pclock, and
312  *                           caller is responsible to free memory
313  *                           of vclock_index
314  *
315  * @pclock_index: phc index of ptp pclock.
316  * @vclock_index: pointer to pointer of vclock index.
317  *
318  * return number of vclocks.
319  */
320 int ptp_get_vclocks_index(int pclock_index, int **vclock_index);
321 
322 /**
323  * ptp_convert_timestamp() - convert timestamp to a ptp vclock time
324  *
325  * @hwtstamps:    skb_shared_hwtstamps structure pointer
326  * @vclock_index: phc index of ptp vclock.
327  */
328 void ptp_convert_timestamp(struct skb_shared_hwtstamps *hwtstamps,
329 			   int vclock_index);
330 
331 #else
332 static inline struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
333 						   struct device *parent)
334 { return NULL; }
335 static inline int ptp_clock_unregister(struct ptp_clock *ptp)
336 { return 0; }
337 static inline void ptp_clock_event(struct ptp_clock *ptp,
338 				   struct ptp_clock_event *event)
339 { }
340 static inline int ptp_clock_index(struct ptp_clock *ptp)
341 { return -1; }
342 static inline int ptp_find_pin(struct ptp_clock *ptp,
343 			       enum ptp_pin_function func, unsigned int chan)
344 { return -1; }
345 static inline int ptp_schedule_worker(struct ptp_clock *ptp,
346 				      unsigned long delay)
347 { return -EOPNOTSUPP; }
348 static inline void ptp_cancel_worker_sync(struct ptp_clock *ptp)
349 { }
350 static inline int ptp_get_vclocks_index(int pclock_index, int **vclock_index)
351 { return 0; }
352 static inline void ptp_convert_timestamp(struct skb_shared_hwtstamps *hwtstamps,
353 					 int vclock_index)
354 { }
355 
356 #endif
357 
358 static inline void ptp_read_system_prets(struct ptp_system_timestamp *sts)
359 {
360 	if (sts)
361 		ktime_get_real_ts64(&sts->pre_ts);
362 }
363 
364 static inline void ptp_read_system_postts(struct ptp_system_timestamp *sts)
365 {
366 	if (sts)
367 		ktime_get_real_ts64(&sts->post_ts);
368 }
369 
370 #endif
371