1 /*
2 * Copyright (c) 2014-2015 Wind River Systems, Inc.
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 /**
8 * @file
9 * @brief Variables needed for system clock
10 *
11 *
12 * Declare variables used by both system timer device driver and kernel
13 * components that use timer functionality.
14 */
15
16 #ifndef ZEPHYR_INCLUDE_SYS_CLOCK_H_
17 #define ZEPHYR_INCLUDE_SYS_CLOCK_H_
18
19 #include <zephyr/sys/util.h>
20 #include <zephyr/sys/dlist.h>
21
22 #include <zephyr/toolchain.h>
23 #include <zephyr/types.h>
24
25 #include <zephyr/sys/time_units.h>
26
27 #ifdef __cplusplus
28 extern "C" {
29 #endif
30
31 /**
32 * @addtogroup clock_apis
33 * @{
34 */
35
36 /**
37 * @brief Tick precision used in timeout APIs
38 *
39 * This type defines the word size of the timeout values used in
40 * k_timeout_t objects, and thus defines an upper bound on maximum
41 * timeout length (or equivalently minimum tick duration). Note that
42 * this does not affect the size of the system uptime counter, which
43 * is always a 64 bit count of ticks.
44 */
45 #ifdef CONFIG_TIMEOUT_64BIT
46 typedef int64_t k_ticks_t;
47 #else
48 typedef uint32_t k_ticks_t;
49 #endif
50
51 #define K_TICKS_FOREVER ((k_ticks_t) -1)
52
53 /**
54 * @brief Kernel timeout type
55 *
56 * Timeout arguments presented to kernel APIs are stored in this
57 * opaque type, which is capable of representing times in various
58 * formats and units. It should be constructed from application data
59 * using one of the macros defined for this purpose (e.g. `K_MSEC()`,
60 * `K_TIMEOUT_ABS_TICKS()`, etc...), or be one of the two constants
61 * K_NO_WAIT or K_FOREVER. Applications should not inspect the
62 * internal data once constructed. Timeout values may be compared for
63 * equality with the `K_TIMEOUT_EQ()` macro.
64 */
65 typedef struct {
66 k_ticks_t ticks;
67 } k_timeout_t;
68
69 /**
70 * @brief Compare timeouts for equality
71 *
72 * The k_timeout_t object is an opaque struct that should not be
73 * inspected by application code. This macro exists so that users can
74 * test timeout objects for equality with known constants
75 * (e.g. K_NO_WAIT and K_FOREVER) when implementing their own APIs in
76 * terms of Zephyr timeout constants.
77 *
78 * @return True if the timeout objects are identical
79 */
80 #define K_TIMEOUT_EQ(a, b) ((a).ticks == (b).ticks)
81
82 /** number of nanoseconds per micorsecond */
83 #define NSEC_PER_USEC 1000U
84
85 /** number of nanoseconds per millisecond */
86 #define NSEC_PER_MSEC 1000000U
87
88 /** number of microseconds per millisecond */
89 #define USEC_PER_MSEC 1000U
90
91 /** number of milliseconds per second */
92 #define MSEC_PER_SEC 1000U
93
94 /** number of seconds per minute */
95 #define SEC_PER_MIN 60U
96
97 /** number of minutes per hour */
98 #define MIN_PER_HOUR 60U
99
100 /** number of hours per day */
101 #define HOUR_PER_DAY 24U
102
103 /** number of microseconds per second */
104 #define USEC_PER_SEC ((USEC_PER_MSEC) * (MSEC_PER_SEC))
105
106 /** number of nanoseconds per second */
107 #define NSEC_PER_SEC ((NSEC_PER_USEC) * (USEC_PER_MSEC) * (MSEC_PER_SEC))
108
109 /** @} */
110
111 /** @cond INTERNAL_HIDDEN */
112 #define Z_TIMEOUT_NO_WAIT ((k_timeout_t) {0})
113 #if defined(__cplusplus) && ((__cplusplus - 0) < 202002L)
114 #define Z_TIMEOUT_TICKS(t) ((k_timeout_t) { (t) })
115 #else
116 #define Z_TIMEOUT_TICKS(t) ((k_timeout_t) { .ticks = (t) })
117 #endif
118 #define Z_FOREVER Z_TIMEOUT_TICKS(K_TICKS_FOREVER)
119
120 #ifdef CONFIG_TIMEOUT_64BIT
121 # define Z_TIMEOUT_MS(t) Z_TIMEOUT_TICKS((k_ticks_t)k_ms_to_ticks_ceil64(MAX(t, 0)))
122 # define Z_TIMEOUT_US(t) Z_TIMEOUT_TICKS((k_ticks_t)k_us_to_ticks_ceil64(MAX(t, 0)))
123 # define Z_TIMEOUT_NS(t) Z_TIMEOUT_TICKS((k_ticks_t)k_ns_to_ticks_ceil64(MAX(t, 0)))
124 # define Z_TIMEOUT_CYC(t) Z_TIMEOUT_TICKS((k_ticks_t)k_cyc_to_ticks_ceil64(MAX(t, 0)))
125 # define Z_TIMEOUT_MS_TICKS(t) ((k_ticks_t)k_ms_to_ticks_ceil64(MAX(t, 0)))
126 #else
127 # define Z_TIMEOUT_MS(t) Z_TIMEOUT_TICKS((k_ticks_t)k_ms_to_ticks_ceil32(MAX(t, 0)))
128 # define Z_TIMEOUT_US(t) Z_TIMEOUT_TICKS((k_ticks_t)k_us_to_ticks_ceil32(MAX(t, 0)))
129 # define Z_TIMEOUT_NS(t) Z_TIMEOUT_TICKS((k_ticks_t)k_ns_to_ticks_ceil32(MAX(t, 0)))
130 # define Z_TIMEOUT_CYC(t) Z_TIMEOUT_TICKS((k_ticks_t)k_cyc_to_ticks_ceil32(MAX(t, 0)))
131 # define Z_TIMEOUT_MS_TICKS(t) ((k_ticks_t)k_ms_to_ticks_ceil32(MAX(t, 0)))
132 #endif
133
134 /* Converts between absolute timeout expiration values (packed into
135 * the negative space below K_TICKS_FOREVER) and (non-negative) delta
136 * timeout values. If the result of Z_TICK_ABS(t) is >= 0, then the
137 * value was an absolute timeout with the returned expiration time.
138 * Note that this macro is bidirectional: Z_TICK_ABS(Z_TICK_ABS(t)) ==
139 * t for all inputs, and that the representation of K_TICKS_FOREVER is
140 * the same value in both spaces! Clever, huh?
141 */
142 #define Z_TICK_ABS(t) (K_TICKS_FOREVER - 1 - (t))
143
144 /* added tick needed to account for tick in progress */
145 #define _TICK_ALIGN 1
146
147 /** @endcond */
148
149 #if defined(CONFIG_SYS_CLOCK_EXISTS) && \
150 (CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC == 0)
151 #error "SYS_CLOCK_HW_CYCLES_PER_SEC must be non-zero!"
152 #endif
153
154
155 /* kernel clocks */
156
157 /*
158 * We default to using 64-bit intermediates in timescale conversions,
159 * but if the HW timer cycles/sec, ticks/sec and ms/sec are all known
160 * to be nicely related, then we can cheat with 32 bits instead.
161 */
162 /**
163 * @addtogroup clock_apis
164 * @{
165 */
166
167 #ifdef CONFIG_SYS_CLOCK_EXISTS
168
169 #if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME) || \
170 (MSEC_PER_SEC % CONFIG_SYS_CLOCK_TICKS_PER_SEC) || \
171 (CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC % CONFIG_SYS_CLOCK_TICKS_PER_SEC)
172 #define _NEED_PRECISE_TICK_MS_CONVERSION
173 #endif
174
175 #endif
176
177 /**
178 * SYS_CLOCK_HW_CYCLES_TO_NS_AVG converts CPU clock cycles to nanoseconds
179 * and calculates the average cycle time
180 */
181 #define SYS_CLOCK_HW_CYCLES_TO_NS_AVG(X, NCYCLES) \
182 (uint32_t)(k_cyc_to_ns_floor64(X) / NCYCLES)
183
184 /**
185 *
186 * @brief Return the lower part of the current system tick count
187 *
188 * @return the current system tick count
189 *
190 */
191 uint32_t sys_clock_tick_get_32(void);
192
193 /**
194 *
195 * @brief Return the current system tick count
196 *
197 * @return the current system tick count
198 *
199 */
200 int64_t sys_clock_tick_get(void);
201
202 #ifndef CONFIG_SYS_CLOCK_EXISTS
203 #define sys_clock_tick_get() (0)
204 #define sys_clock_tick_get_32() (0)
205 #endif
206
207 #ifdef CONFIG_SYS_CLOCK_EXISTS
208
209 /**
210 * @brief Kernel timepoint type
211 *
212 * Absolute timepoints are stored in this opaque type.
213 * It is best not to inspect its content directly.
214 *
215 * @see sys_timepoint_calc()
216 * @see sys_timepoint_timeout()
217 * @see sys_timepoint_expired()
218 */
219 typedef struct { uint64_t tick; } k_timepoint_t;
220
221 /**
222 * @brief Calculate a timepoint value
223 *
224 * Returns a timepoint corresponding to the expiration (relative to an
225 * unlocked "now"!) of a timeout object. When used correctly, this should
226 * be called once, synchronously with the user passing a new timeout value.
227 * It should not be used iteratively to adjust a timeout (see
228 * `sys_timepoint_timeout()` for that purpose).
229 *
230 * @param timeout Timeout value relative to current time (may also be
231 * `K_FOREVER` or `K_NO_WAIT`).
232 * @retval Timepoint value corresponding to given timeout
233 *
234 * @see sys_timepoint_timeout()
235 * @see sys_timepoint_expired()
236 */
237 k_timepoint_t sys_timepoint_calc(k_timeout_t timeout);
238
239 /**
240 * @brief Remaining time to given timepoint
241 *
242 * Returns the timeout interval between current time and provided timepoint.
243 * If the timepoint is now in the past or if it was created with `K_NO_WAIT`
244 * then `K_NO_WAIT` is returned. If it was created with `K_FOREVER` then
245 * `K_FOREVER` is returned.
246 *
247 * @param timepoint Timepoint for which a timeout value is wanted.
248 * @retval Corresponding timeout value.
249 *
250 * @see sys_timepoint_calc()
251 */
252 k_timeout_t sys_timepoint_timeout(k_timepoint_t timepoint);
253
254 /**
255 * @brief Provided for backward compatibility.
256 *
257 * This is deprecated. Consider `sys_timepoint_calc()` instead.
258 *
259 * @see sys_timepoint_calc()
260 */
261 __deprecated
sys_clock_timeout_end_calc(k_timeout_t timeout)262 static inline uint64_t sys_clock_timeout_end_calc(k_timeout_t timeout)
263 {
264 k_timepoint_t tp = sys_timepoint_calc(timeout);
265
266 return tp.tick;
267 }
268
269 /**
270 * @brief Compare two timepoint values.
271 *
272 * This function is used to compare two timepoint values.
273 *
274 * @param a Timepoint to compare
275 * @param b Timepoint to compare against.
276 * @return zero if both timepoints are the same. Negative value if timepoint @a a is before
277 * timepoint @a b, positive otherwise.
278 */
sys_timepoint_cmp(k_timepoint_t a,k_timepoint_t b)279 static inline int sys_timepoint_cmp(k_timepoint_t a, k_timepoint_t b)
280 {
281 if (a.tick == b.tick) {
282 return 0;
283 }
284 return a.tick < b.tick ? -1 : 1;
285 }
286
287 #else
288
289 /*
290 * When timers are configured out, timepoints can't relate to anything.
291 * The best we can do is to preserve whether or not they are derived from
292 * K_NO_WAIT. Anything else will translate back to K_FOREVER.
293 */
294 typedef struct { bool wait; } k_timepoint_t;
295
sys_timepoint_calc(k_timeout_t timeout)296 static inline k_timepoint_t sys_timepoint_calc(k_timeout_t timeout)
297 {
298 k_timepoint_t timepoint;
299
300 timepoint.wait = !K_TIMEOUT_EQ(timeout, Z_TIMEOUT_NO_WAIT);
301 return timepoint;
302 }
303
sys_timepoint_timeout(k_timepoint_t timepoint)304 static inline k_timeout_t sys_timepoint_timeout(k_timepoint_t timepoint)
305 {
306 return timepoint.wait ? Z_FOREVER : Z_TIMEOUT_NO_WAIT;
307 }
308
sys_timepoint_cmp(k_timepoint_t a,k_timepoint_t b)309 static inline int sys_timepoint_cmp(k_timepoint_t a, k_timepoint_t b)
310 {
311 if (a.wait == b.wait) {
312 return 0;
313 }
314 return b.wait ? -1 : 1;
315 }
316
317 #endif
318
319 /**
320 * @brief Indicates if timepoint is expired
321 *
322 * @param timepoint Timepoint to evaluate
323 * @retval true if the timepoint is in the past, false otherwise
324 *
325 * @see sys_timepoint_calc()
326 */
sys_timepoint_expired(k_timepoint_t timepoint)327 static inline bool sys_timepoint_expired(k_timepoint_t timepoint)
328 {
329 return K_TIMEOUT_EQ(sys_timepoint_timeout(timepoint), Z_TIMEOUT_NO_WAIT);
330 }
331
332 /** @} */
333
334 #ifdef __cplusplus
335 }
336 #endif
337
338 #endif /* ZEPHYR_INCLUDE_SYS_CLOCK_H_ */
339
