Commit 2fe998cd authored by Piotr Zięcik's avatar Piotr Zięcik Committed by Anas Nashif
Browse files

kernel: Deprecate sys_clock_us_per_tick variable. 



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: default avatarPiotr Zięcik <piotr.ziecik@nordicsemi.no>
parent 408a5806

drivers/timer/hpet.c

+2 −3
Original line number Diff line number Diff line
@@ -580,11 +580,10 @@ int _sys_clock_driver_init(struct device *device) 
 */



	/*

	 * Convert the 'sys_clock_us_per_tick' value

	 * from microseconds to femptoseconds

	 * Get tick time (in femptoseconds).

	 */



	tickFempto = (u64_t)sys_clock_us_per_tick * 1000000000;

	tickFempto = 1000000000000000ull / sys_clock_ticks_per_sec;



	/*

	 * This driver shall read the COUNTER_CLK_PERIOD value from the general

drivers/timer/native_posix_timer.c

+1 −1
Original line number Diff line number Diff line
@@ -103,7 +103,7 @@ int _sys_clock_driver_init(struct device *device) 
{

	ARG_UNUSED(device);



	tick_period = sys_clock_us_per_tick;

	tick_period = 1000000ul / sys_clock_ticks_per_sec;



	hwtimer_enable(tick_period);

include/sys_clock.h

+5 −3
Original line number Diff line number Diff line
@@ -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

samples/net/zperf/src/zperf_internal.h

+4 −4
Original line number Diff line number Diff line
@@ -30,8 +30,8 @@ 


#define HW_CYCLES_TO_USEC(__hw_cycle__) \

	( \

		((u64_t)(__hw_cycle__) * (u64_t)sys_clock_us_per_tick) / \

		((u64_t)sys_clock_hw_cycles_per_tick) \

		((u64_t)(__hw_cycle__) * (u64_t)USEC_PER_SEC) / \

		((u64_t)sys_clock_hw_cycles_per_sec) \

	)



#define HW_CYCLES_TO_SEC(__hw_cycle__) \
@@ -42,8 +42,8 @@ 


#define USEC_TO_HW_CYCLES(__usec__) \

	( \

		((u64_t)(__usec__) * (u64_t)sys_clock_hw_cycles_per_tick) / \

		((u64_t)sys_clock_us_per_tick) \

		((u64_t)(__usec__) * (u64_t)sys_clock_hw_cycles_per_sec) / \

		((u64_t)USEC_PER_SEC) \

	)



#define SEC_TO_HW_CYCLES(__sec__) \

tests/kernel/context/src/main.c

+1 −1
Original line number Diff line number Diff line
@@ -245,7 +245,7 @@ static void _test_kernel_cpu_idle(int atomic) 
			k_cpu_idle();

		}

		/* calculating milliseconds per tick*/

		tms += sys_clock_us_per_tick / USEC_PER_MSEC;

		tms += __ticks_to_ms(1);

		tms2 = k_uptime_get_32();

		zassert_false(tms2 < tms, "Bad ms per tick value computed,"

			      "got %d which is less than %d\n",

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