kernel: retrieve system timer clock frequency at runtime or static

update kernel timeout logic based on retrieve system timer clock
frequency at runtime or static way based on Kconfig
TIMER_READS_ITS_FREQUENCY_AT_RUNTIME

Signed-off-by: Najumon B.A <[email protected]>

Author: najumon1980

include/zephyr/sys_clock.h

@@ -146,9 +146,9 @@ typedef struct {
 
 /** @endcond */
 
-#if defined(CONFIG_SYS_CLOCK_EXISTS) && \
-	(CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC == 0)
-#error "SYS_CLOCK_HW_CYCLES_PER_SEC must be non-zero!"
+#if defined(CONFIG_SYS_CLOCK_EXISTS) && !defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME)
+BUILD_ASSERT(CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC != 0,
+	"SYS_CLOCK_HW_CYCLES_PER_SEC must be non-zero!");
 #endif
 
 
@@ -164,7 +164,7 @@ typedef struct {
  * @{
  */
 
-#ifdef CONFIG_SYS_CLOCK_EXISTS
+#if defined(CONFIG_SYS_CLOCK_EXISTS) && !defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME)
 
 #if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME) || \
 	(MSEC_PER_SEC % CONFIG_SYS_CLOCK_TICKS_PER_SEC) || \

kernel/Kconfig

@@ -799,6 +799,7 @@ config SYS_CLOCK_TICKS_PER_SEC
 
 config SYS_CLOCK_HW_CYCLES_PER_SEC
 	int "System clock's h/w timer frequency"
+	depends on !TIMER_READS_ITS_FREQUENCY_AT_RUNTIME
 	help
 	  This option specifies the frequency of the hardware timer used for the
 	  system clock (in Hz). This option is set by the SOC's or board's Kconfig file

kernel/timeout.c

@@ -25,7 +25,7 @@ static struct k_spinlock timeout_lock;
 static int announce_remaining;
 
 #if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME)
-int z_clock_hw_cycles_per_sec = CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC;
+int z_clock_hw_cycles_per_sec;
 
 #ifdef CONFIG_USERSPACE
 static inline int z_vrfy_sys_clock_hw_cycles_per_sec_runtime_get(void)