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john stultz734efb42006-06-26 00:25:05 -07001/* linux/include/linux/clocksource.h
2 *
3 * This file contains the structure definitions for clocksources.
4 *
5 * If you are not a clocksource, or timekeeping code, you should
6 * not be including this file!
7 */
8#ifndef _LINUX_CLOCKSOURCE_H
9#define _LINUX_CLOCKSOURCE_H
10
11#include <linux/types.h>
12#include <linux/timex.h>
13#include <linux/time.h>
14#include <linux/list.h>
Eric Dumazet329c8d82007-05-08 00:27:57 -070015#include <linux/cache.h>
Thomas Gleixner5d8b34f2007-02-16 01:27:43 -080016#include <linux/timer.h>
Martin Schwidefskyf1b82742009-08-14 15:47:21 +020017#include <linux/init.h>
David Lechner02fad5e2016-03-09 18:16:54 -060018#include <linux/of.h>
john stultz734efb42006-06-26 00:25:05 -070019#include <asm/div64.h>
20#include <asm/io.h>
21
Thomas Gleixner5d8b34f2007-02-16 01:27:43 -080022struct clocksource;
Thomas Gleixner09ac3692013-04-25 20:31:44 +000023struct module;
john stultz734efb42006-06-26 00:25:05 -070024
H. Peter Anvinae7bd112011-07-21 13:34:05 -070025#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA
Andy Lutomirski433bd802011-07-13 09:24:13 -040026#include <asm/clocksource.h>
H. Peter Anvinae7bd112011-07-21 13:34:05 -070027#endif
Andy Lutomirski433bd802011-07-13 09:24:13 -040028
john stultz734efb42006-06-26 00:25:05 -070029/**
30 * struct clocksource - hardware abstraction for a free running counter
31 * Provides mostly state-free accessors to the underlying hardware.
Patrick Ohlya038a352009-02-12 05:03:34 +000032 * This is the structure used for system time.
john stultz734efb42006-06-26 00:25:05 -070033 *
34 * @name: ptr to clocksource name
35 * @list: list head for registration
36 * @rating: rating value for selection (higher is better)
37 * To avoid rating inflation the following
38 * list should give you a guide as to how
39 * to assign your clocksource a rating
40 * 1-99: Unfit for real use
41 * Only available for bootup and testing purposes.
42 * 100-199: Base level usability.
43 * Functional for real use, but not desired.
44 * 200-299: Good.
45 * A correct and usable clocksource.
46 * 300-399: Desired.
47 * A reasonably fast and accurate clocksource.
48 * 400-499: Perfect
49 * The ideal clocksource. A must-use where
50 * available.
Magnus Damm8e196082009-04-21 12:24:00 -070051 * @read: returns a cycle value, passes clocksource as argument
Magnus Damm4614e6a2009-04-21 12:24:02 -070052 * @enable: optional function to enable the clocksource
53 * @disable: optional function to disable the clocksource
john stultz734efb42006-06-26 00:25:05 -070054 * @mask: bitmask for two's complement
55 * subtraction of non 64 bit counters
Martin Schwidefsky0a544192009-08-14 15:47:28 +020056 * @mult: cycle to nanosecond multiplier
john stultz734efb42006-06-26 00:25:05 -070057 * @shift: cycle to nanosecond divisor (power of two)
Jon Hunter98962462009-08-18 12:45:10 -050058 * @max_idle_ns: max idle time permitted by the clocksource (nsecs)
Kusanagi Kouichib1b73d02011-12-19 18:13:19 +090059 * @maxadj: maximum adjustment value to mult (~11%)
John Stultzfb82fe22015-03-11 21:16:31 -070060 * @max_cycles: maximum safe cycle value which won't overflow on multiplication
Thomas Gleixner73b08d22007-02-16 01:27:36 -080061 * @flags: flags describing special properties
Andy Lutomirski433bd802011-07-13 09:24:13 -040062 * @archdata: arch-specific data
Magnus Dammc54a42b2010-02-02 14:41:41 -080063 * @suspend: suspend function for the clocksource, if necessary
Thomas Gleixnerb52f52a2007-05-09 02:35:15 -070064 * @resume: resume function for the clocksource, if necessary
Thomas Gleixner09ac3692013-04-25 20:31:44 +000065 * @owner: module reference, must be set by clocksource in modules
Thomas Gleixner09a99822015-11-19 11:43:09 +010066 *
67 * Note: This struct is not used in hotpathes of the timekeeping code
68 * because the timekeeper caches the hot path fields in its own data
69 * structure, so no line cache alignment is required,
70 *
71 * The pointer to the clocksource itself is handed to the read
72 * callback. If you need extra information there you can wrap struct
73 * clocksource into your own struct. Depending on the amount of
74 * information you need you should consider to cache line align that
75 * structure.
john stultz734efb42006-06-26 00:25:05 -070076 */
77struct clocksource {
Magnus Damm8e196082009-04-21 12:24:00 -070078 cycle_t (*read)(struct clocksource *cs);
john stultz734efb42006-06-26 00:25:05 -070079 cycle_t mask;
80 u32 mult;
81 u32 shift;
Jon Hunter98962462009-08-18 12:45:10 -050082 u64 max_idle_ns;
John Stultzd65670a2011-10-31 17:06:35 -040083 u32 maxadj;
H. Peter Anvinae7bd112011-07-21 13:34:05 -070084#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA
Andy Lutomirski433bd802011-07-13 09:24:13 -040085 struct arch_clocksource_data archdata;
Tony Luck0aa366f2007-07-20 11:22:30 -070086#endif
John Stultzfb82fe22015-03-11 21:16:31 -070087 u64 max_cycles;
Thomas Gleixner369db4c2011-05-18 21:33:40 +000088 const char *name;
89 struct list_head list;
90 int rating;
Thomas Gleixner369db4c2011-05-18 21:33:40 +000091 int (*enable)(struct clocksource *cs);
92 void (*disable)(struct clocksource *cs);
93 unsigned long flags;
94 void (*suspend)(struct clocksource *cs);
95 void (*resume)(struct clocksource *cs);
Thomas Gleixner5d8b34f2007-02-16 01:27:43 -080096
Kusanagi Kouichib1b73d02011-12-19 18:13:19 +090097 /* private: */
Thomas Gleixner5d8b34f2007-02-16 01:27:43 -080098#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
99 /* Watchdog related data, used by the framework */
100 struct list_head wd_list;
Thomas Gleixnerb5199512011-06-16 16:22:08 +0200101 cycle_t cs_last;
Thomas Gleixner5d8b34f2007-02-16 01:27:43 -0800102 cycle_t wd_last;
103#endif
Thomas Gleixner09ac3692013-04-25 20:31:44 +0000104 struct module *owner;
Thomas Gleixner09a99822015-11-19 11:43:09 +0100105};
john stultz734efb42006-06-26 00:25:05 -0700106
Thomas Gleixner73b08d22007-02-16 01:27:36 -0800107/*
108 * Clock source flags bits::
109 */
Thomas Gleixner5d8b34f2007-02-16 01:27:43 -0800110#define CLOCK_SOURCE_IS_CONTINUOUS 0x01
111#define CLOCK_SOURCE_MUST_VERIFY 0x02
112
113#define CLOCK_SOURCE_WATCHDOG 0x10
114#define CLOCK_SOURCE_VALID_FOR_HRES 0x20
Martin Schwidefskyc55c87c2009-08-14 15:47:25 +0200115#define CLOCK_SOURCE_UNSTABLE 0x40
Feng Tang5caf4632013-03-12 11:56:46 +0800116#define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80
Thomas Gleixner332962f2013-07-04 22:46:45 +0200117#define CLOCK_SOURCE_RESELECT 0x100
Thomas Gleixner73b08d22007-02-16 01:27:36 -0800118
Jim Cromie7f9f3032006-06-26 00:25:15 -0700119/* simplify initialization of mask field */
Atsushi Nemoto1d76c262008-01-30 13:30:01 +0100120#define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)
john stultz734efb42006-06-26 00:25:05 -0700121
Alexander Kuleshov7aca0c02016-02-26 19:14:13 -0800122static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from)
123{
124 /* freq = cyc/from
125 * mult/2^shift = ns/cyc
126 * mult = ns/cyc * 2^shift
127 * mult = from/freq * 2^shift
128 * mult = from * 2^shift / freq
129 * mult = (from<<shift) / freq
130 */
131 u64 tmp = ((u64)from) << shift_constant;
132
133 tmp += freq/2; /* round for do_div */
134 do_div(tmp, freq);
135
136 return (u32)tmp;
137}
138
john stultz734efb42006-06-26 00:25:05 -0700139/**
140 * clocksource_khz2mult - calculates mult from khz and shift
141 * @khz: Clocksource frequency in KHz
142 * @shift_constant: Clocksource shift factor
143 *
144 * Helper functions that converts a khz counter frequency to a timsource
145 * multiplier, given the clocksource shift value
146 */
147static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant)
148{
Alexander Kuleshov7aca0c02016-02-26 19:14:13 -0800149 return clocksource_freq2mult(khz, shift_constant, NSEC_PER_MSEC);
john stultz734efb42006-06-26 00:25:05 -0700150}
151
152/**
153 * clocksource_hz2mult - calculates mult from hz and shift
154 * @hz: Clocksource frequency in Hz
155 * @shift_constant: Clocksource shift factor
156 *
157 * Helper functions that converts a hz counter
158 * frequency to a timsource multiplier, given the
159 * clocksource shift value
160 */
161static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)
162{
Alexander Kuleshov7aca0c02016-02-26 19:14:13 -0800163 return clocksource_freq2mult(hz, shift_constant, NSEC_PER_SEC);
john stultz734efb42006-06-26 00:25:05 -0700164}
165
166/**
Martin Schwidefsky155ec602009-08-14 15:47:26 +0200167 * clocksource_cyc2ns - converts clocksource cycles to nanoseconds
Kusanagi Kouichib1b73d02011-12-19 18:13:19 +0900168 * @cycles: cycles
169 * @mult: cycle to nanosecond multiplier
170 * @shift: cycle to nanosecond divisor (power of two)
john stultz734efb42006-06-26 00:25:05 -0700171 *
Martin Schwidefsky155ec602009-08-14 15:47:26 +0200172 * Converts cycles to nanoseconds, using the given mult and shift.
john stultz734efb42006-06-26 00:25:05 -0700173 *
174 * XXX - This could use some mult_lxl_ll() asm optimization
175 */
Martin Schwidefsky155ec602009-08-14 15:47:26 +0200176static inline s64 clocksource_cyc2ns(cycle_t cycles, u32 mult, u32 shift)
john stultz734efb42006-06-26 00:25:05 -0700177{
Martin Schwidefsky155ec602009-08-14 15:47:26 +0200178 return ((u64) cycles * mult) >> shift;
john stultz5eb6d202006-06-26 00:25:07 -0700179}
180
181
Thomas Gleixnera89c7ed2013-04-25 20:31:46 +0000182extern int clocksource_unregister(struct clocksource*);
Jason Wessel7c3078b2008-02-15 14:55:54 -0600183extern void clocksource_touch_watchdog(void);
Thomas Gleixner92c7e002007-02-16 01:27:33 -0800184extern void clocksource_change_rating(struct clocksource *cs, int rating);
Magnus Dammc54a42b2010-02-02 14:41:41 -0800185extern void clocksource_suspend(void);
Thomas Gleixnerb52f52a2007-05-09 02:35:15 -0700186extern void clocksource_resume(void);
Bjorn Helgaas96a2adb2014-10-13 18:59:09 -0600187extern struct clocksource * __init clocksource_default_clock(void);
Thomas Gleixner7285dd72009-08-28 20:25:24 +0200188extern void clocksource_mark_unstable(struct clocksource *cs);
john stultz734efb42006-06-26 00:25:05 -0700189
Stephen Boyd87d8b9e2013-07-18 16:21:14 -0700190extern u64
John Stultzfb82fe22015-03-11 21:16:31 -0700191clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cycles);
Thomas Gleixner7d2f9442009-11-11 14:05:29 +0000192extern void
193clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec);
194
John Stultzd7e81c22010-05-07 18:07:38 -0700195/*
196 * Don't call __clocksource_register_scale directly, use
197 * clocksource_register_hz/khz
198 */
199extern int
200__clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq);
John Stultz852db462010-07-13 17:56:28 -0700201extern void
John Stultzfba9e072015-03-11 21:16:40 -0700202__clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq);
John Stultzd7e81c22010-05-07 18:07:38 -0700203
John Stultzf8935982015-03-11 21:16:37 -0700204/*
205 * Don't call this unless you are a default clocksource
206 * (AKA: jiffies) and absolutely have to.
207 */
208static inline int __clocksource_register(struct clocksource *cs)
209{
210 return __clocksource_register_scale(cs, 1, 0);
211}
212
John Stultzd7e81c22010-05-07 18:07:38 -0700213static inline int clocksource_register_hz(struct clocksource *cs, u32 hz)
214{
215 return __clocksource_register_scale(cs, 1, hz);
216}
217
218static inline int clocksource_register_khz(struct clocksource *cs, u32 khz)
219{
220 return __clocksource_register_scale(cs, 1000, khz);
221}
222
John Stultzfba9e072015-03-11 21:16:40 -0700223static inline void __clocksource_update_freq_hz(struct clocksource *cs, u32 hz)
John Stultz852db462010-07-13 17:56:28 -0700224{
John Stultzfba9e072015-03-11 21:16:40 -0700225 __clocksource_update_freq_scale(cs, 1, hz);
John Stultz852db462010-07-13 17:56:28 -0700226}
227
John Stultzfba9e072015-03-11 21:16:40 -0700228static inline void __clocksource_update_freq_khz(struct clocksource *cs, u32 khz)
John Stultz852db462010-07-13 17:56:28 -0700229{
John Stultzfba9e072015-03-11 21:16:40 -0700230 __clocksource_update_freq_scale(cs, 1000, khz);
John Stultz852db462010-07-13 17:56:28 -0700231}
John Stultzd7e81c22010-05-07 18:07:38 -0700232
john stultzacc9a9d2007-02-16 01:28:17 -0800233
Thomas Gleixnerba919d12013-04-25 20:31:44 +0000234extern int timekeeping_notify(struct clocksource *clock);
Martin Schwidefsky75c51582009-08-14 15:47:30 +0200235
Russell King442c8172011-05-08 14:06:52 +0100236extern cycle_t clocksource_mmio_readl_up(struct clocksource *);
237extern cycle_t clocksource_mmio_readl_down(struct clocksource *);
238extern cycle_t clocksource_mmio_readw_up(struct clocksource *);
239extern cycle_t clocksource_mmio_readw_down(struct clocksource *);
240
241extern int clocksource_mmio_init(void __iomem *, const char *,
242 unsigned long, int, unsigned, cycle_t (*)(struct clocksource *));
243
Russell King8c414ff2011-05-08 18:50:20 +0100244extern int clocksource_i8253_init(void);
245
Rob Herring54196cc2014-05-08 16:09:24 -0500246#define CLOCKSOURCE_OF_DECLARE(name, compat, fn) \
Daniel Lezcano177cf6e2016-06-07 00:27:44 +0200247 OF_DECLARE_1_RET(clksrc, name, compat, fn)
Daniel Lezcanob7c4db82016-05-31 16:25:59 +0200248
Marc Zyngieraad83b152015-09-28 15:49:16 +0100249#ifdef CONFIG_CLKSRC_PROBE
Marc Zyngier3722ed22015-09-28 15:49:18 +0100250extern void clocksource_probe(void);
Stephen Warrene1d7ef12013-01-30 10:49:30 -0700251#else
Marc Zyngier3722ed22015-09-28 15:49:18 +0100252static inline void clocksource_probe(void) {}
Stephen Warrenae278a92012-11-19 16:41:20 -0700253#endif
254
Marc Zyngierc625f762015-09-28 15:49:15 +0100255#define CLOCKSOURCE_ACPI_DECLARE(name, table_id, fn) \
256 ACPI_DECLARE_PROBE_ENTRY(clksrc, name, table_id, 0, NULL, 0, fn)
257
john stultz734efb42006-06-26 00:25:05 -0700258#endif /* _LINUX_CLOCKSOURCE_H */