util: Provide macro to cause a minor delay in busy loops in POSIX ARCH

In the POSIX ARCH, code takes zero time to execute,
so busy wait loops become infinite loops, unless we
force the loop to take a bit of time.

Signed-off-by: Alberto Escolar Piedras <[email protected]>

Author: aescolar

include/zephyr/sys/util.h

@@ -578,6 +578,24 @@ char *utf8_lcpy(char *dst, const char *src, size_t n);
 /** @brief Number of Hz in @p x MHz */
 #define MHZ(x) (KHZ(x) * 1000)
 
+/**
+ * @brief For the POSIX architecture add a minimal delay in a busy wait loop.
+ * For other architectures this is a no-op.
+ *
+ * In the POSIX ARCH, code takes zero simulated time to execute,
+ * so busy wait loops become infinite loops, unless we
+ * force the loop to take a bit of time.
+ * Include this macro in all busy wait/spin loops
+ * so they will also work when building for the POSIX architecture.
+ *
+ * @param t Time in microseconds we will busy wait
+ */
+#if defined(CONFIG_ARCH_POSIX)
+#define Z_SPIN_DELAY(t) k_busy_wait(t)
+#else
+#define Z_SPIN_DELAY(t)
+#endif
+
 /**
  * @brief Wait for an expression to return true with a timeout
  *