kernel: Move k_busy_wait from thread to timeout

K_busy_wait is the only function from thread.c that is used when
CONFIG_MULTITHREADING=n. Moving to timeout since it fits better there
as it requires sys clock to be present.

Signed-off-by: Krzysztof Chruscinski <[email protected]>

Author: nordic-krch

kernel/thread.c

@@ -120,44 +120,6 @@ bool z_is_thread_essential(void)
 	return (_current->base.user_options & K_ESSENTIAL) == K_ESSENTIAL;
 }
 
-#ifdef CONFIG_SYS_CLOCK_EXISTS
-void z_impl_k_busy_wait(uint32_t usec_to_wait)
-{
-	if (usec_to_wait == 0U) {
-		return;
-	}
-
-#if !defined(CONFIG_ARCH_HAS_CUSTOM_BUSY_WAIT)
-	uint32_t start_cycles = k_cycle_get_32();
-
-	/* use 64-bit math to prevent overflow when multiplying */
-	uint32_t cycles_to_wait = (uint32_t)(
-		(uint64_t)usec_to_wait *
-		(uint64_t)sys_clock_hw_cycles_per_sec() /
-		(uint64_t)USEC_PER_SEC
-	);
-
-	for (;;) {
-		uint32_t current_cycles = k_cycle_get_32();
-
-		/* this handles the rollover on an unsigned 32-bit value */
-		if ((current_cycles - start_cycles) >= cycles_to_wait) {
-			break;
-		}
-	}
-#else
-	arch_busy_wait(usec_to_wait);
-#endif /* CONFIG_ARCH_HAS_CUSTOM_BUSY_WAIT */
-}
-
-#ifdef CONFIG_USERSPACE
-static inline void z_vrfy_k_busy_wait(uint32_t usec_to_wait)
-{
-	z_impl_k_busy_wait(usec_to_wait);
-}
-#include <syscalls/k_busy_wait_mrsh.c>
-#endif /* CONFIG_USERSPACE */
-#endif /* CONFIG_SYS_CLOCK_EXISTS */
 
 #ifdef CONFIG_THREAD_CUSTOM_DATA
 void z_impl_k_thread_custom_data_set(void *value)

kernel/timeout.c

@@ -297,6 +297,43 @@ static inline int64_t z_vrfy_k_uptime_ticks(void)
 #include <syscalls/k_uptime_ticks_mrsh.c>
 #endif
 
+void z_impl_k_busy_wait(uint32_t usec_to_wait)
+{
+	if (usec_to_wait == 0U) {
+		return;
+	}
+
+#if !defined(CONFIG_ARCH_HAS_CUSTOM_BUSY_WAIT)
+	uint32_t start_cycles = k_cycle_get_32();
+
+	/* use 64-bit math to prevent overflow when multiplying */
+	uint32_t cycles_to_wait = (uint32_t)(
+		(uint64_t)usec_to_wait *
+		(uint64_t)sys_clock_hw_cycles_per_sec() /
+		(uint64_t)USEC_PER_SEC
+	);
+
+	for (;;) {
+		uint32_t current_cycles = k_cycle_get_32();
+
+		/* this handles the rollover on an unsigned 32-bit value */
+		if ((current_cycles - start_cycles) >= cycles_to_wait) {
+			break;
+		}
+	}
+#else
+	arch_busy_wait(usec_to_wait);
+#endif /* CONFIG_ARCH_HAS_CUSTOM_BUSY_WAIT */
+}
+
+#ifdef CONFIG_USERSPACE
+static inline void z_vrfy_k_busy_wait(uint32_t usec_to_wait)
+{
+	z_impl_k_busy_wait(usec_to_wait);
+}
+#include <syscalls/k_busy_wait_mrsh.c>
+#endif /* CONFIG_USERSPACE */
+
 /* Returns the uptime expiration (relative to an unlocked "now"!) of a
  * timeout object.  When used correctly, this should be called once,
  * synchronously with the user passing a new timeout value.  It should