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kernel: Deprecate sys_clock_us_per_tick variable.

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On some architectures tick time cannot be expressed as integer
number of microseconds, introducing error in calculations using
sys_clock_us_per_tick variable.

This commit deprecates the sys_clock_us_per_tick variable and
replaces its usage by more precise calculations based on
sys_clock_hw_cycles_per_sec and sys_clock_ticks_per_sec.

Signed-off-by: Piotr Zięcik <piotr.ziecik@nordicsemi.no>
This commit is contained in:
Piotr Zięcik 2018-07-17 15:14:32 +02:00 • committed by Anas Nashif
commit 2fe998cdef
7 changed files with 14 additions and 14 deletions
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8
include/sys_clock.h
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@ -21,6 +21,7 @@ extern "C" {
#endif
#ifndef _ASMLANGUAGE
#include <toolchain.h>
#include <zephyr/types.h>
#if defined(CONFIG_SYS_CLOCK_EXISTS) && \
@ -46,8 +47,10 @@ extern int sys_clock_hw_cycles_per_sec;
/*
* sys_clock_us_per_tick global variable represents a number
* of microseconds in one OS timer tick
*
* Note: This variable is deprecated and will be removed soon!
*/
extern int sys_clock_us_per_tick;
__deprecated extern int sys_clock_us_per_tick;
/*
* sys_clock_hw_cycles_per_tick global variable represents a number
@ -75,8 +78,7 @@ extern int sys_clock_hw_cycles_per_tick;
/* SYS_CLOCK_HW_CYCLES_TO_NS64 converts CPU clock cycles to nanoseconds */
#define SYS_CLOCK_HW_CYCLES_TO_NS64(X) \
(((u64_t)(X) * sys_clock_us_per_tick * NSEC_PER_USEC) / \
sys_clock_hw_cycles_per_tick)
(((u64_t)(X) * NSEC_PER_SEC) / sys_clock_hw_cycles_per_sec)
/*
* SYS_CLOCK_HW_CYCLES_TO_NS_AVG converts CPU clock cycles to nanoseconds