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 seconds per hour */
98 #define SEC_PER_HOUR 3600U
99
100 /** number of seconds per day */
101 #define SEC_PER_DAY 86400U
102
103 /** number of minutes per hour */
104 #define MIN_PER_HOUR 60U
105
106 /** number of hours per day */
107 #define HOUR_PER_DAY 24U
108
109 /** number of microseconds per second */
110 #define USEC_PER_SEC ((USEC_PER_MSEC) * (MSEC_PER_SEC))
111
112 /** number of nanoseconds per second */
113 #define NSEC_PER_SEC ((NSEC_PER_USEC) * (USEC_PER_MSEC) * (MSEC_PER_SEC))
114
115 /** @} */
116
117 /** @cond INTERNAL_HIDDEN */
118 #define Z_TIMEOUT_NO_WAIT ((k_timeout_t) {0})
119 #if defined(__cplusplus) && ((__cplusplus - 0) < 202002L)
120 #define Z_TIMEOUT_TICKS(t) ((k_timeout_t) { (t) })
121 #else
122 #define Z_TIMEOUT_TICKS(t) ((k_timeout_t) { .ticks = (t) })
123 #endif
124 #define Z_FOREVER Z_TIMEOUT_TICKS(K_TICKS_FOREVER)
125
126 #ifdef CONFIG_TIMEOUT_64BIT
127 # define Z_TIMEOUT_MS(t) Z_TIMEOUT_TICKS((k_ticks_t)k_ms_to_ticks_ceil64(MAX(t, 0)))
128 # define Z_TIMEOUT_US(t) Z_TIMEOUT_TICKS((k_ticks_t)k_us_to_ticks_ceil64(MAX(t, 0)))
129 # define Z_TIMEOUT_NS(t) Z_TIMEOUT_TICKS((k_ticks_t)k_ns_to_ticks_ceil64(MAX(t, 0)))
130 # define Z_TIMEOUT_CYC(t) Z_TIMEOUT_TICKS((k_ticks_t)k_cyc_to_ticks_ceil64(MAX(t, 0)))
131 # define Z_TIMEOUT_MS_TICKS(t) ((k_ticks_t)k_ms_to_ticks_ceil64(MAX(t, 0)))
132 #else
133 # define Z_TIMEOUT_MS(t) Z_TIMEOUT_TICKS((k_ticks_t)k_ms_to_ticks_ceil32(MAX(t, 0)))
134 # define Z_TIMEOUT_US(t) Z_TIMEOUT_TICKS((k_ticks_t)k_us_to_ticks_ceil32(MAX(t, 0)))
135 # define Z_TIMEOUT_NS(t) Z_TIMEOUT_TICKS((k_ticks_t)k_ns_to_ticks_ceil32(MAX(t, 0)))
136 # define Z_TIMEOUT_CYC(t) Z_TIMEOUT_TICKS((k_ticks_t)k_cyc_to_ticks_ceil32(MAX(t, 0)))
137 # define Z_TIMEOUT_MS_TICKS(t) ((k_ticks_t)k_ms_to_ticks_ceil32(MAX(t, 0)))
138 #endif
139
140 /* Converts between absolute timeout expiration values (packed into
141 * the negative space below K_TICKS_FOREVER) and (non-negative) delta
142 * timeout values. If the result of Z_TICK_ABS(t) is >= 0, then the
143 * value was an absolute timeout with the returned expiration time.
144 * Note that this macro is bidirectional: Z_TICK_ABS(Z_TICK_ABS(t)) ==
145 * t for all inputs, and that the representation of K_TICKS_FOREVER is
146 * the same value in both spaces! Clever, huh?
147 */
148 #define Z_TICK_ABS(t) (K_TICKS_FOREVER - 1 - (t))
149
150 /* added tick needed to account for tick in progress */
151 #define _TICK_ALIGN 1
152
153 /** @endcond */
154
155 #if defined(CONFIG_SYS_CLOCK_EXISTS) && \
156 (CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC == 0)
157 #error "SYS_CLOCK_HW_CYCLES_PER_SEC must be non-zero!"
158 #endif
159
160
161 /* kernel clocks */
162
163 /*
164 * We default to using 64-bit intermediates in timescale conversions,
165 * but if the HW timer cycles/sec, ticks/sec and ms/sec are all known
166 * to be nicely related, then we can cheat with 32 bits instead.
167 */
168 /**
169 * @addtogroup clock_apis
170 * @{
171 */
172
173 #ifdef CONFIG_SYS_CLOCK_EXISTS
174
175 #if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME) || \
176 (MSEC_PER_SEC % CONFIG_SYS_CLOCK_TICKS_PER_SEC) || \
177 (CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC % CONFIG_SYS_CLOCK_TICKS_PER_SEC)
178 #define _NEED_PRECISE_TICK_MS_CONVERSION
179 #endif
180
181 #endif
182
183 /**
184 * SYS_CLOCK_HW_CYCLES_TO_NS_AVG converts CPU clock cycles to nanoseconds
185 * and calculates the average cycle time
186 */
187 #define SYS_CLOCK_HW_CYCLES_TO_NS_AVG(X, NCYCLES) \
188 (uint32_t)(k_cyc_to_ns_floor64(X) / NCYCLES)
189
190 /**
191 *
192 * @brief Return the lower part of the current system tick count
193 *
194 * @return the current system tick count
195 *
196 */
197 uint32_t sys_clock_tick_get_32(void);
198
199 /**
200 *
201 * @brief Return the current system tick count
202 *
203 * @return the current system tick count
204 *
205 */
206 int64_t sys_clock_tick_get(void);
207
208 #ifndef CONFIG_SYS_CLOCK_EXISTS
209 #define sys_clock_tick_get() (0)
210 #define sys_clock_tick_get_32() (0)
211 #endif
212
213 #ifdef CONFIG_SYS_CLOCK_EXISTS
214
215 /**
216 * @brief Kernel timepoint type
217 *
218 * Absolute timepoints are stored in this opaque type.
219 * It is best not to inspect its content directly.
220 *
221 * @see sys_timepoint_calc()
222 * @see sys_timepoint_timeout()
223 * @see sys_timepoint_expired()
224 */
225 typedef struct { uint64_t tick; } k_timepoint_t;
226
227 /**
228 * @brief Calculate a timepoint value
229 *
230 * Returns a timepoint corresponding to the expiration (relative to an
231 * unlocked "now"!) of a timeout object. When used correctly, this should
232 * be called once, synchronously with the user passing a new timeout value.
233 * It should not be used iteratively to adjust a timeout (see
234 * `sys_timepoint_timeout()` for that purpose).
235 *
236 * @param timeout Timeout value relative to current time (may also be
237 * `K_FOREVER` or `K_NO_WAIT`).
238 * @retval Timepoint value corresponding to given timeout
239 *
240 * @see sys_timepoint_timeout()
241 * @see sys_timepoint_expired()
242 */
243 k_timepoint_t sys_timepoint_calc(k_timeout_t timeout);
244
245 /**
246 * @brief Remaining time to given timepoint
247 *
248 * Returns the timeout interval between current time and provided timepoint.
249 * If the timepoint is now in the past or if it was created with `K_NO_WAIT`
250 * then `K_NO_WAIT` is returned. If it was created with `K_FOREVER` then
251 * `K_FOREVER` is returned.
252 *
253 * @param timepoint Timepoint for which a timeout value is wanted.
254 * @retval Corresponding timeout value.
255 *
256 * @see sys_timepoint_calc()
257 */
258 k_timeout_t sys_timepoint_timeout(k_timepoint_t timepoint);
259
260 /**
261 * @brief Compare two timepoint values.
262 *
263 * This function is used to compare two timepoint values.
264 *
265 * @param a Timepoint to compare
266 * @param b Timepoint to compare against.
267 * @return zero if both timepoints are the same. Negative value if timepoint @a a is before
268 * timepoint @a b, positive otherwise.
269 */
sys_timepoint_cmp(k_timepoint_t a,k_timepoint_t b)270 static inline int sys_timepoint_cmp(k_timepoint_t a, k_timepoint_t b)
271 {
272 if (a.tick == b.tick) {
273 return 0;
274 }
275 return a.tick < b.tick ? -1 : 1;
276 }
277
278 #else
279
280 /*
281 * When timers are configured out, timepoints can't relate to anything.
282 * The best we can do is to preserve whether or not they are derived from
283 * K_NO_WAIT. Anything else will translate back to K_FOREVER.
284 */
285 typedef struct { bool wait; } k_timepoint_t;
286
sys_timepoint_calc(k_timeout_t timeout)287 static inline k_timepoint_t sys_timepoint_calc(k_timeout_t timeout)
288 {
289 k_timepoint_t timepoint;
290
291 timepoint.wait = !K_TIMEOUT_EQ(timeout, Z_TIMEOUT_NO_WAIT);
292 return timepoint;
293 }
294
sys_timepoint_timeout(k_timepoint_t timepoint)295 static inline k_timeout_t sys_timepoint_timeout(k_timepoint_t timepoint)
296 {
297 return timepoint.wait ? Z_FOREVER : Z_TIMEOUT_NO_WAIT;
298 }
299
sys_timepoint_cmp(k_timepoint_t a,k_timepoint_t b)300 static inline int sys_timepoint_cmp(k_timepoint_t a, k_timepoint_t b)
301 {
302 if (a.wait == b.wait) {
303 return 0;
304 }
305 return b.wait ? -1 : 1;
306 }
307
308 #endif
309
310 /**
311 * @brief Indicates if timepoint is expired
312 *
313 * @param timepoint Timepoint to evaluate
314 * @retval true if the timepoint is in the past, false otherwise
315 *
316 * @see sys_timepoint_calc()
317 */
sys_timepoint_expired(k_timepoint_t timepoint)318 static inline bool sys_timepoint_expired(k_timepoint_t timepoint)
319 {
320 return K_TIMEOUT_EQ(sys_timepoint_timeout(timepoint), Z_TIMEOUT_NO_WAIT);
321 }
322
323 /** @} */
324
325 #ifdef __cplusplus
326 }
327 #endif
328
329 #endif /* ZEPHYR_INCLUDE_SYS_CLOCK_H_ */
330
