180 lines
4.9 KiB
C
180 lines
4.9 KiB
C
/*
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* Copyright (c) 2011-2014, Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief Misc utilities
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*
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* Misc utilities usable by the kernel and application code.
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*/
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#ifndef _UTIL__H_
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#define _UTIL__H_
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef _ASMLANGUAGE
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#include <stdint.h>
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/* Helper to pass a int as a pointer or vice-versa.
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* Those are available for 32 bits architectures:
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*/
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#define POINTER_TO_UINT(x) ((uint32_t) (x))
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#define UINT_TO_POINTER(x) ((void *) (x))
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#define POINTER_TO_INT(x) ((int32_t) (x))
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#define INT_TO_POINTER(x) ((void *) (x))
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/* Evaluates to 0 if cond is true-ish; compile error otherwise */
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#define ZERO_OR_COMPILE_ERROR(cond) ((int) sizeof(char[1 - 2 * !(cond)]) - 1)
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/* Evaluates to 0 if array is an array; compile error if not array (e.g.
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* pointer)
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*/
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#define IS_ARRAY(array) \
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ZERO_OR_COMPILE_ERROR( \
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!__builtin_types_compatible_p(__typeof__(array), \
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__typeof__(&(array)[0])))
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/* Evaluates to number of elements in an array; compile error if not
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* an array (e.g. pointer)
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*/
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#define ARRAY_SIZE(array) \
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((unsigned long) (IS_ARRAY(array) + \
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(sizeof(array) / sizeof((array)[0]))))
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/* Evaluates to 1 if ptr is part of array, 0 otherwise; compile error if
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* "array" argument is not an array (e.g. "ptr" and "array" mixed up)
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*/
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#define PART_OF_ARRAY(array, ptr) \
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((ptr) && ((ptr) >= &array[0] && (ptr) < &array[ARRAY_SIZE(array)]))
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#define CONTAINER_OF(ptr, type, field) \
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((type *)(((char *)(ptr)) - offsetof(type, field)))
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/* round "x" up/down to next multiple of "align" (which must be a power of 2) */
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#define ROUND_UP(x, align) \
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(((unsigned long)(x) + ((unsigned long)align - 1)) & \
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~((unsigned long)align - 1))
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#define ROUND_DOWN(x, align) ((unsigned long)(x) & ~((unsigned long)align - 1))
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#define ceiling_fraction(numerator, divider) \
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(((numerator) + ((divider) - 1)) / (divider))
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#ifdef INLINED
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#define INLINE inline
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#else
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#define INLINE
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#endif
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#ifndef max
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#define max(a, b) (((a) > (b)) ? (a) : (b))
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#endif
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#ifndef min
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#define min(a, b) (((a) < (b)) ? (a) : (b))
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#endif
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static inline int is_power_of_two(unsigned int x)
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{
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return (x != 0) && !(x & (x - 1));
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}
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static inline int64_t arithmetic_shift_right(int64_t value, uint8_t shift)
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{
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int64_t sign_ext;
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if (shift == 0) {
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return value;
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}
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/* extract sign bit */
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sign_ext = (value >> 63) & 1;
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/* make all bits of sign_ext be the same as the value's sign bit */
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sign_ext = -sign_ext;
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/* shift value and fill opened bit positions with sign bit */
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return (value >> shift) | (sign_ext << (64 - shift));
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}
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#endif /* !_ASMLANGUAGE */
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/* KB, MB, GB */
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#define KB(x) ((x) << 10)
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#define MB(x) (KB(x) << 10)
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#define GB(x) (MB(x) << 10)
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/* KHZ, MHZ */
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#define KHZ(x) ((x) * 1000)
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#define MHZ(x) (KHZ(x) * 1000)
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#ifndef BIT
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#define BIT(n) (1UL << (n))
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#endif
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#define BIT_MASK(n) (BIT(n) - 1)
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/**
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* @brief Check for macro definition in compiler-visible expressions
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*
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* This trick was pioneered in Linux as the config_enabled() macro.
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* The madness has the effect of taking a macro value that may be
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* defined to "1" (e.g. CONFIG_MYFEATURE), or may not be defined at
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* all and turning it into a literal expression that can be used at
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* "runtime". That is, it works similarly to
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* "defined(CONFIG_MYFEATURE)" does except that it is an expansion
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* that can exist in a standard expression and be seen by the compiler
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* and optimizer. Thus much ifdef usage can be replaced with cleaner
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* expressions like:
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*
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* if (IS_ENABLED(CONFIG_MYFEATURE))
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* myfeature_enable();
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*
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* INTERNAL
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* First pass just to expand any existing macros, we need the macro
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* value to be e.g. a literal "1" at expansion time in the next macro,
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* not "(1)", etc... Standard recursive expansion does not work.
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*/
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#define IS_ENABLED(config_macro) _IS_ENABLED1(config_macro)
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/* Now stick on a "_XXXX" prefix, it will now be "_XXXX1" if config_macro
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* is "1", or just "_XXXX" if it's undefined.
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* ENABLED: _IS_ENABLED2(_XXXX1)
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* DISABLED _IS_ENABLED2(_XXXX)
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*/
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#define _IS_ENABLED1(config_macro) _IS_ENABLED2(_XXXX##config_macro)
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/* Here's the core trick, we map "_XXXX1" to "_YYYY," (i.e. a string
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* with a trailing comma), so it has the effect of making this a
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* two-argument tuple to the preprocessor only in the case where the
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* value is defined to "1"
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* ENABLED: _YYYY, <--- note comma!
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* DISABLED: _XXXX
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*/
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#define _XXXX1 _YYYY,
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/* Then we append an extra argument to fool the gcc preprocessor into
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* accepting it as a varargs macro.
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* arg1 arg2 arg3
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* ENABLED: _IS_ENABLED3(_YYYY, 1, 0)
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* DISABLED _IS_ENABLED3(_XXXX 1, 0)
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*/
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#define _IS_ENABLED2(one_or_two_args) _IS_ENABLED3(one_or_two_args 1, 0)
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/* And our second argument is thus now cooked to be 1 in the case
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* where the value is defined to 1, and 0 if not:
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*/
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#define _IS_ENABLED3(ignore_this, val, ...) val
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#ifdef __cplusplus
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}
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#endif
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#endif /* _UTIL__H_ */
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