1 /*
2 * Copyright (c) 2011-2014, Wind River Systems, Inc.
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 /**
8 * @file
9 * @brief Misc utilities
10 *
11 * Misc utilities usable by the kernel and application code.
12 */
13
14 #ifndef ZEPHYR_INCLUDE_SYS_UTIL_H_
15 #define ZEPHYR_INCLUDE_SYS_UTIL_H_
16
17 #include <zephyr/sys/util_macro.h>
18 #include <zephyr/toolchain.h>
19
20 /* needs to be outside _ASMLANGUAGE so 'true' and 'false' can turn
21 * into '1' and '0' for asm or linker scripts
22 */
23 #include <stdbool.h>
24
25 #ifndef _ASMLANGUAGE
26
27 #include <zephyr/types.h>
28 #include <stddef.h>
29 #include <stdint.h>
30
31 /** @brief Number of bits that make up a type */
32 #define NUM_BITS(t) (sizeof(t) * 8)
33
34 #ifdef __cplusplus
35 extern "C" {
36 #endif
37
38 /**
39 * @defgroup sys-util Utility Functions
40 * @ingroup utilities
41 * @{
42 */
43
44 /** @brief Cast @p x, a pointer, to an unsigned integer. */
45 #define POINTER_TO_UINT(x) ((uintptr_t) (x))
46 /** @brief Cast @p x, an unsigned integer, to a <tt>void*</tt>. */
47 #define UINT_TO_POINTER(x) ((void *) (uintptr_t) (x))
48 /** @brief Cast @p x, a pointer, to a signed integer. */
49 #define POINTER_TO_INT(x) ((intptr_t) (x))
50 /** @brief Cast @p x, a signed integer, to a <tt>void*</tt>. */
51 #define INT_TO_POINTER(x) ((void *) (intptr_t) (x))
52
53 #if !(defined(__CHAR_BIT__) && defined(__SIZEOF_LONG__) && defined(__SIZEOF_LONG_LONG__))
54 # error Missing required predefined macros for BITS_PER_LONG calculation
55 #endif
56
57 /** Number of bits in a long int. */
58 #define BITS_PER_LONG (__CHAR_BIT__ * __SIZEOF_LONG__)
59
60 /** Number of bits in a long long int. */
61 #define BITS_PER_LONG_LONG (__CHAR_BIT__ * __SIZEOF_LONG_LONG__)
62
63 /**
64 * @brief Create a contiguous bitmask starting at bit position @p l
65 * and ending at position @p h.
66 */
67 #define GENMASK(h, l) \
68 (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
69
70 /**
71 * @brief Create a contiguous 64-bit bitmask starting at bit position @p l
72 * and ending at position @p h.
73 */
74 #define GENMASK64(h, l) \
75 (((~0ULL) - (1ULL << (l)) + 1) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
76
77 /** @brief Extract the Least Significant Bit from @p value. */
78 #define LSB_GET(value) ((value) & -(value))
79
80 /**
81 * @brief Extract a bitfield element from @p value corresponding to
82 * the field mask @p mask.
83 */
84 #define FIELD_GET(mask, value) (((value) & (mask)) / LSB_GET(mask))
85
86 /**
87 * @brief Prepare a bitfield element using @p value with @p mask representing
88 * its field position and width. The result should be combined
89 * with other fields using a logical OR.
90 */
91 #define FIELD_PREP(mask, value) (((value) * LSB_GET(mask)) & (mask))
92
93 /** @brief 0 if @p cond is true-ish; causes a compile error otherwise. */
94 #define ZERO_OR_COMPILE_ERROR(cond) ((int) sizeof(char[1 - 2 * !(cond)]) - 1)
95
96 #if defined(__cplusplus)
97
98 /* The built-in function used below for type checking in C is not
99 * supported by GNU C++.
100 */
101 #define ARRAY_SIZE(array) (sizeof(array) / sizeof((array)[0]))
102
103 #else /* __cplusplus */
104
105 /**
106 * @brief Zero if @p array has an array type, a compile error otherwise
107 *
108 * This macro is available only from C, not C++.
109 */
110 #define IS_ARRAY(array) \
111 ZERO_OR_COMPILE_ERROR( \
112 !__builtin_types_compatible_p(__typeof__(array), \
113 __typeof__(&(array)[0])))
114
115 /**
116 * @brief Number of elements in the given @p array
117 *
118 * In C++, due to language limitations, this will accept as @p array
119 * any type that implements <tt>operator[]</tt>. The results may not be
120 * particularly meaningful in this case.
121 *
122 * In C, passing a pointer as @p array causes a compile error.
123 */
124 #define ARRAY_SIZE(array) \
125 ((size_t) (IS_ARRAY(array) + (sizeof(array) / sizeof((array)[0]))))
126
127 #endif /* __cplusplus */
128
129 /**
130 * @brief Whether @p ptr is an element of @p array
131 *
132 * This macro can be seen as a slightly stricter version of @ref PART_OF_ARRAY
133 * in that it also ensures that @p ptr is aligned to an array-element boundary
134 * of @p array.
135 *
136 * In C, passing a pointer as @p array causes a compile error.
137 *
138 * @param array the array in question
139 * @param ptr the pointer to check
140 *
141 * @return 1 if @p ptr is part of @p array, 0 otherwise
142 */
143 #define IS_ARRAY_ELEMENT(array, ptr) \
144 ((ptr) && POINTER_TO_UINT(array) <= POINTER_TO_UINT(ptr) && \
145 POINTER_TO_UINT(ptr) < POINTER_TO_UINT(&(array)[ARRAY_SIZE(array)]) && \
146 (POINTER_TO_UINT(ptr) - POINTER_TO_UINT(array)) % sizeof((array)[0]) == 0)
147
148 /**
149 * @brief Index of @p ptr within @p array
150 *
151 * With `CONFIG_ASSERT=y`, this macro will trigger a runtime assertion
152 * when @p ptr does not fall into the range of @p array or when @p ptr
153 * is not aligned to an array-element boundary of @p array.
154 *
155 * In C, passing a pointer as @p array causes a compile error.
156 *
157 * @param array the array in question
158 * @param ptr pointer to an element of @p array
159 *
160 * @return the array index of @p ptr within @p array, on success
161 */
162 #define ARRAY_INDEX(array, ptr) \
163 ({ \
164 __ASSERT_NO_MSG(IS_ARRAY_ELEMENT(array, ptr)); \
165 (__typeof__((array)[0]) *)(ptr) - (array); \
166 })
167
168 /**
169 * @brief Check if a pointer @p ptr lies within @p array.
170 *
171 * In C but not C++, this causes a compile error if @p array is not an array
172 * (e.g. if @p ptr and @p array are mixed up).
173 *
174 * @param array an array
175 * @param ptr a pointer
176 * @return 1 if @p ptr is part of @p array, 0 otherwise
177 */
178 #define PART_OF_ARRAY(array, ptr) \
179 ((ptr) && POINTER_TO_UINT(array) <= POINTER_TO_UINT(ptr) && \
180 POINTER_TO_UINT(ptr) < POINTER_TO_UINT(&(array)[ARRAY_SIZE(array)]))
181
182 /**
183 * @brief Array-index of @p ptr within @p array, rounded down
184 *
185 * This macro behaves much like @ref ARRAY_INDEX with the notable
186 * difference that it accepts any @p ptr in the range of @p array rather than
187 * exclusively a @p ptr aligned to an array-element boundary of @p array.
188 *
189 * With `CONFIG_ASSERT=y`, this macro will trigger a runtime assertion
190 * when @p ptr does not fall into the range of @p array.
191 *
192 * In C, passing a pointer as @p array causes a compile error.
193 *
194 * @param array the array in question
195 * @param ptr pointer to an element of @p array
196 *
197 * @return the array index of @p ptr within @p array, on success
198 */
199 #define ARRAY_INDEX_FLOOR(array, ptr) \
200 ({ \
201 __ASSERT_NO_MSG(PART_OF_ARRAY(array, ptr)); \
202 (POINTER_TO_UINT(ptr) - POINTER_TO_UINT(array)) / sizeof((array)[0]); \
203 })
204
205 /**
206 * @brief Validate if two entities have a compatible type
207 *
208 * @param a the first entity to be compared
209 * @param b the second entity to be compared
210 * @return 1 if the two elements are compatible, 0 if they are not
211 */
212 #define SAME_TYPE(a, b) __builtin_types_compatible_p(__typeof__(a), __typeof__(b))
213
214 /**
215 * @brief Validate CONTAINER_OF parameters, only applies to C mode.
216 */
217 #ifndef __cplusplus
218 #define CONTAINER_OF_VALIDATE(ptr, type, field) \
219 BUILD_ASSERT(SAME_TYPE(*(ptr), ((type *)0)->field) || \
220 SAME_TYPE(*(ptr), void), \
221 "pointer type mismatch in CONTAINER_OF");
222 #else
223 #define CONTAINER_OF_VALIDATE(ptr, type, field)
224 #endif
225
226 /**
227 * @brief Get a pointer to a structure containing the element
228 *
229 * Example:
230 *
231 * struct foo {
232 * int bar;
233 * };
234 *
235 * struct foo my_foo;
236 * int *ptr = &my_foo.bar;
237 *
238 * struct foo *container = CONTAINER_OF(ptr, struct foo, bar);
239 *
240 * Above, @p container points at @p my_foo.
241 *
242 * @param ptr pointer to a structure element
243 * @param type name of the type that @p ptr is an element of
244 * @param field the name of the field within the struct @p ptr points to
245 * @return a pointer to the structure that contains @p ptr
246 */
247 #define CONTAINER_OF(ptr, type, field) \
248 ({ \
249 CONTAINER_OF_VALIDATE(ptr, type, field) \
250 ((type *)(((char *)(ptr)) - offsetof(type, field))); \
251 })
252
253 /**
254 * @brief Value of @p x rounded up to the next multiple of @p align.
255 */
256 #define ROUND_UP(x, align) \
257 ((((unsigned long)(x) + ((unsigned long)(align) - 1)) / \
258 (unsigned long)(align)) * (unsigned long)(align))
259
260 /**
261 * @brief Value of @p x rounded down to the previous multiple of @p align.
262 */
263 #define ROUND_DOWN(x, align) \
264 (((unsigned long)(x) / (unsigned long)(align)) * (unsigned long)(align))
265
266 /** @brief Value of @p x rounded up to the next word boundary. */
267 #define WB_UP(x) ROUND_UP(x, sizeof(void *))
268
269 /** @brief Value of @p x rounded down to the previous word boundary. */
270 #define WB_DN(x) ROUND_DOWN(x, sizeof(void *))
271
272 /**
273 * @brief Divide and round up.
274 *
275 * Example:
276 * @code{.c}
277 * DIV_ROUND_UP(1, 2); // 1
278 * DIV_ROUND_UP(3, 2); // 2
279 * @endcode
280 *
281 * @param n Numerator.
282 * @param d Denominator.
283 *
284 * @return The result of @p n / @p d, rounded up.
285 */
286 #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
287
288 /**
289 * @brief Divide and round to the nearest integer.
290 *
291 * Example:
292 * @code{.c}
293 * DIV_ROUND_CLOSEST(5, 2); // 3
294 * DIV_ROUND_CLOSEST(5, -2); // -3
295 * DIV_ROUND_CLOSEST(5, 3); // 2
296 * @endcode
297 *
298 * @param n Numerator.
299 * @param d Denominator.
300 *
301 * @return The result of @p n / @p d, rounded to the nearest integer.
302 */
303 #define DIV_ROUND_CLOSEST(n, d) \
304 ((((n) < 0) ^ ((d) < 0)) ? ((n) - ((d) / 2)) / (d) : \
305 ((n) + ((d) / 2)) / (d))
306
307 /**
308 * @brief Ceiling function applied to @p numerator / @p divider as a fraction.
309 * @deprecated Use DIV_ROUND_UP() instead.
310 */
311 #define ceiling_fraction(numerator, divider) __DEPRECATED_MACRO \
312 DIV_ROUND_UP(numerator, divider)
313
314 #ifndef MAX
315 /**
316 * @brief Obtain the maximum of two values.
317 *
318 * @note Arguments are evaluated twice. Use Z_MAX for a GCC-only, single
319 * evaluation version
320 *
321 * @param a First value.
322 * @param b Second value.
323 *
324 * @returns Maximum value of @p a and @p b.
325 */
326 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
327 #endif
328
329 #ifndef MIN
330 /**
331 * @brief Obtain the minimum of two values.
332 *
333 * @note Arguments are evaluated twice. Use Z_MIN for a GCC-only, single
334 * evaluation version
335 *
336 * @param a First value.
337 * @param b Second value.
338 *
339 * @returns Minimum value of @p a and @p b.
340 */
341 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
342 #endif
343
344 #ifndef CLAMP
345 /**
346 * @brief Clamp a value to a given range.
347 *
348 * @note Arguments are evaluated multiple times. Use Z_CLAMP for a GCC-only,
349 * single evaluation version.
350 *
351 * @param val Value to be clamped.
352 * @param low Lowest allowed value (inclusive).
353 * @param high Highest allowed value (inclusive).
354 *
355 * @returns Clamped value.
356 */
357 #define CLAMP(val, low, high) (((val) <= (low)) ? (low) : MIN(val, high))
358 #endif
359
360 /**
361 * @brief Checks if a value is within range.
362 *
363 * @note @p val is evaluated twice.
364 *
365 * @param val Value to be checked.
366 * @param min Lower bound (inclusive).
367 * @param max Upper bound (inclusive).
368 *
369 * @retval true If value is within range
370 * @retval false If the value is not within range
371 */
372 #define IN_RANGE(val, min, max) ((val) >= (min) && (val) <= (max))
373
374 /**
375 * @brief Is @p x a power of two?
376 * @param x value to check
377 * @return true if @p x is a power of two, false otherwise
378 */
is_power_of_two(unsigned int x)379 static inline bool is_power_of_two(unsigned int x)
380 {
381 return IS_POWER_OF_TWO(x);
382 }
383
384 /**
385 * @brief Arithmetic shift right
386 * @param value value to shift
387 * @param shift number of bits to shift
388 * @return @p value shifted right by @p shift; opened bit positions are
389 * filled with the sign bit
390 */
arithmetic_shift_right(int64_t value,uint8_t shift)391 static inline int64_t arithmetic_shift_right(int64_t value, uint8_t shift)
392 {
393 int64_t sign_ext;
394
395 if (shift == 0U) {
396 return value;
397 }
398
399 /* extract sign bit */
400 sign_ext = (value >> 63) & 1;
401
402 /* make all bits of sign_ext be the same as the value's sign bit */
403 sign_ext = -sign_ext;
404
405 /* shift value and fill opened bit positions with sign bit */
406 return (value >> shift) | (sign_ext << (64 - shift));
407 }
408
409 /**
410 * @brief byte by byte memcpy.
411 *
412 * Copy `size` bytes of `src` into `dest`. This is guaranteed to be done byte by byte.
413 *
414 * @param dst Pointer to the destination memory.
415 * @param src Pointer to the source of the data.
416 * @param size The number of bytes to copy.
417 */
bytecpy(void * dst,const void * src,size_t size)418 static inline void bytecpy(void *dst, const void *src, size_t size)
419 {
420 size_t i;
421
422 for (i = 0; i < size; ++i) {
423 ((volatile uint8_t *)dst)[i] = ((volatile const uint8_t *)src)[i];
424 }
425 }
426
427 /**
428 * @brief byte by byte swap.
429 *
430 * Swap @a size bytes between memory regions @a a and @a b. This is
431 * guaranteed to be done byte by byte.
432 *
433 * @param a Pointer to the the first memory region.
434 * @param b Pointer to the the second memory region.
435 * @param size The number of bytes to swap.
436 */
byteswp(void * a,void * b,size_t size)437 static inline void byteswp(void *a, void *b, size_t size)
438 {
439 uint8_t t;
440 uint8_t *aa = (uint8_t *)a;
441 uint8_t *bb = (uint8_t *)b;
442
443 for (; size > 0; --size) {
444 t = *aa;
445 *aa++ = *bb;
446 *bb++ = t;
447 }
448 }
449
450 /**
451 * @brief Convert a single character into a hexadecimal nibble.
452 *
453 * @param c The character to convert
454 * @param x The address of storage for the converted number.
455 *
456 * @return Zero on success or (negative) error code otherwise.
457 */
458 int char2hex(char c, uint8_t *x);
459
460 /**
461 * @brief Convert a single hexadecimal nibble into a character.
462 *
463 * @param c The number to convert
464 * @param x The address of storage for the converted character.
465 *
466 * @return Zero on success or (negative) error code otherwise.
467 */
468 int hex2char(uint8_t x, char *c);
469
470 /**
471 * @brief Convert a binary array into string representation.
472 *
473 * @param buf The binary array to convert
474 * @param buflen The length of the binary array to convert
475 * @param hex Address of where to store the string representation.
476 * @param hexlen Size of the storage area for string representation.
477 *
478 * @return The length of the converted string, or 0 if an error occurred.
479 */
480 size_t bin2hex(const uint8_t *buf, size_t buflen, char *hex, size_t hexlen);
481
482 /**
483 * @brief Convert a hexadecimal string into a binary array.
484 *
485 * @param hex The hexadecimal string to convert
486 * @param hexlen The length of the hexadecimal string to convert.
487 * @param buf Address of where to store the binary data
488 * @param buflen Size of the storage area for binary data
489 *
490 * @return The length of the binary array, or 0 if an error occurred.
491 */
492 size_t hex2bin(const char *hex, size_t hexlen, uint8_t *buf, size_t buflen);
493
494 /**
495 * @brief Convert a binary coded decimal (BCD 8421) value to binary.
496 *
497 * @param bcd BCD 8421 value to convert.
498 *
499 * @return Binary representation of input value.
500 */
bcd2bin(uint8_t bcd)501 static inline uint8_t bcd2bin(uint8_t bcd)
502 {
503 return ((10 * (bcd >> 4)) + (bcd & 0x0F));
504 }
505
506 /**
507 * @brief Convert a binary value to binary coded decimal (BCD 8421).
508 *
509 * @param bin Binary value to convert.
510 *
511 * @return BCD 8421 representation of input value.
512 */
bin2bcd(uint8_t bin)513 static inline uint8_t bin2bcd(uint8_t bin)
514 {
515 return (((bin / 10) << 4) | (bin % 10));
516 }
517
518 /**
519 * @brief Convert a uint8_t into a decimal string representation.
520 *
521 * Convert a uint8_t value into its ASCII decimal string representation.
522 * The string is terminated if there is enough space in buf.
523 *
524 * @param buf Address of where to store the string representation.
525 * @param buflen Size of the storage area for string representation.
526 * @param value The value to convert to decimal string
527 *
528 * @return The length of the converted string (excluding terminator if
529 * any), or 0 if an error occurred.
530 */
531 uint8_t u8_to_dec(char *buf, uint8_t buflen, uint8_t value);
532
533 /**
534 * @brief Properly truncate a NULL-terminated UTF-8 string
535 *
536 * Take a NULL-terminated UTF-8 string and ensure that if the string has been
537 * truncated (by setting the NULL terminator) earlier by other means, that
538 * the string ends with a properly formatted UTF-8 character (1-4 bytes).
539 *
540 * @htmlonly
541 * Example:
542 * char test_str[] = "€€€";
543 * char trunc_utf8[8];
544 *
545 * printf("Original : %s\n", test_str); // €€€
546 * strncpy(trunc_utf8, test_str, sizeof(trunc_utf8));
547 * trunc_utf8[sizeof(trunc_utf8) - 1] = '\0';
548 * printf("Bad : %s\n", trunc_utf8); // €€�
549 * utf8_trunc(trunc_utf8);
550 * printf("Truncated: %s\n", trunc_utf8); // €€
551 * @endhtmlonly
552 *
553 * @param utf8_str NULL-terminated string
554 *
555 * @return Pointer to the @p utf8_str
556 */
557 char *utf8_trunc(char *utf8_str);
558
559 /**
560 * @brief Copies a UTF-8 encoded string from @p src to @p dst
561 *
562 * The resulting @p dst will always be NULL terminated if @p n is larger than 0,
563 * and the @p dst string will always be properly UTF-8 truncated.
564 *
565 * @param dst The destination of the UTF-8 string.
566 * @param src The source string
567 * @param n The size of the @p dst buffer. Maximum number of characters copied
568 * is @p n - 1. If 0 nothing will be done, and the @p dst will not be
569 * NULL terminated.
570 *
571 * @return Pointer to the @p dst
572 */
573 char *utf8_lcpy(char *dst, const char *src, size_t n);
574
575 #define __z_log2d(x) (32 - __builtin_clz(x) - 1)
576 #define __z_log2q(x) (64 - __builtin_clzll(x) - 1)
577 #define __z_log2(x) (sizeof(__typeof__(x)) > 4 ? __z_log2q(x) : __z_log2d(x))
578
579 /**
580 * @brief Compute log2(x)
581 *
582 * @note This macro expands its argument multiple times (to permit use
583 * in constant expressions), which must not have side effects.
584 *
585 * @param x An unsigned integral value to compute logarithm of (positive only)
586 *
587 * @return log2(x) when 1 <= x <= max(x), -1 when x < 1
588 */
589 #define LOG2(x) ((x) < 1 ? -1 : __z_log2(x))
590
591 /**
592 * @brief Compute ceil(log2(x))
593 *
594 * @note This macro expands its argument multiple times (to permit use
595 * in constant expressions), which must not have side effects.
596 *
597 * @param x An unsigned integral value
598 *
599 * @return ceil(log2(x)) when 1 <= x <= max(type(x)), 0 when x < 1
600 */
601 #define LOG2CEIL(x) ((x) < 1 ? 0 : __z_log2((x)-1) + 1)
602
603 /**
604 * @brief Compute next highest power of two
605 *
606 * Equivalent to 2^ceil(log2(x))
607 *
608 * @note This macro expands its argument multiple times (to permit use
609 * in constant expressions), which must not have side effects.
610 *
611 * @param x An unsigned integral value
612 *
613 * @return 2^ceil(log2(x)) or 0 if 2^ceil(log2(x)) would saturate 64-bits
614 */
615 #define NHPOT(x) ((x) < 1 ? 1 : ((x) > (1ULL<<63) ? 0 : 1ULL << LOG2CEIL(x)))
616
617 /**
618 * @brief Determine if a buffer exceeds highest address
619 *
620 * This macro determines if a buffer identified by a starting address @a addr
621 * and length @a buflen spans a region of memory that goes beond the highest
622 * possible address (thereby resulting in a pointer overflow).
623 *
624 * @param addr Buffer starting address
625 * @param buflen Length of the buffer
626 *
627 * @return true if pointer overflow detected, false otherwise
628 */
629 #define Z_DETECT_POINTER_OVERFLOW(addr, buflen) \
630 (((buflen) != 0) && \
631 ((UINTPTR_MAX - (uintptr_t)(addr)) <= ((uintptr_t)((buflen) - 1))))
632
633 #ifdef __cplusplus
634 }
635 #endif
636
637 /* This file must be included at the end of the !_ASMLANGUAGE guard.
638 * It depends on macros defined in this file above which cannot be forward declared.
639 */
640 #include <zephyr/sys/time_units.h>
641
642 #endif /* !_ASMLANGUAGE */
643
644 /** @brief Number of bytes in @p x kibibytes */
645 #ifdef _LINKER
646 /* This is used in linker scripts so need to avoid type casting there */
647 #define KB(x) ((x) << 10)
648 #else
649 #define KB(x) (((size_t)x) << 10)
650 #endif
651 /** @brief Number of bytes in @p x mebibytes */
652 #define MB(x) (KB(x) << 10)
653 /** @brief Number of bytes in @p x gibibytes */
654 #define GB(x) (MB(x) << 10)
655
656 /** @brief Number of Hz in @p x kHz */
657 #define KHZ(x) ((x) * 1000)
658 /** @brief Number of Hz in @p x MHz */
659 #define MHZ(x) (KHZ(x) * 1000)
660
661 /**
662 * @brief For the POSIX architecture add a minimal delay in a busy wait loop.
663 * For other architectures this is a no-op.
664 *
665 * In the POSIX ARCH, code takes zero simulated time to execute,
666 * so busy wait loops become infinite loops, unless we
667 * force the loop to take a bit of time.
668 * Include this macro in all busy wait/spin loops
669 * so they will also work when building for the POSIX architecture.
670 *
671 * @param t Time in microseconds we will busy wait
672 */
673 #if defined(CONFIG_ARCH_POSIX)
674 #define Z_SPIN_DELAY(t) k_busy_wait(t)
675 #else
676 #define Z_SPIN_DELAY(t)
677 #endif
678
679 /**
680 * @brief Wait for an expression to return true with a timeout
681 *
682 * Spin on an expression with a timeout and optional delay between iterations
683 *
684 * Commonly needed when waiting on hardware to complete an asynchronous
685 * request to read/write/initialize/reset, but useful for any expression.
686 *
687 * @param expr Truth expression upon which to poll, e.g.: XYZREG & XYZREG_EN
688 * @param timeout Timeout to wait for in microseconds, e.g.: 1000 (1ms)
689 * @param delay_stmt Delay statement to perform each poll iteration
690 * e.g.: NULL, k_yield(), k_msleep(1) or k_busy_wait(1)
691 *
692 * @retval expr As a boolean return, if false then it has timed out.
693 */
694 #define WAIT_FOR(expr, timeout, delay_stmt) \
695 ({ \
696 uint32_t _wf_cycle_count = k_us_to_cyc_ceil32(timeout); \
697 uint32_t _wf_start = k_cycle_get_32(); \
698 while (!(expr) && (_wf_cycle_count > (k_cycle_get_32() - _wf_start))) { \
699 delay_stmt; \
700 Z_SPIN_DELAY(10); \
701 } \
702 (expr); \
703 })
704
705 /**
706 * @}
707 */
708
709 #endif /* ZEPHYR_INCLUDE_SYS_UTIL_H_ */
710
