2 files changed, 22 insertions, 0 deletions
diff --git a/src/generic/armcm_timer.c b/src/generic/armcm_timer.c
index a9c8ab9f..7f11cd68 100644
--- a/src/generic/armcm_timer.c
+++ b/src/generic/armcm_timer.c
@@ -54,6 +54,20 @@ timer_kick(void)
     SCB->ICSR = SCB_ICSR_PENDSTSET_Msk;
 }
 
+// Implement simple early-boot delay mechanism
+void
+udelay(uint32_t usecs)
+{
+    if (!(CoreDebug->DEMCR & CoreDebug_DEMCR_TRCENA_Msk)) {
+        CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
+        DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;
+    }
+
+    uint32_t end = timer_read_time() + timer_from_us(usecs);
+    while (timer_is_before(timer_read_time(), end))
+        ;
+}
+
 void
 timer_init(void)
 {
diff --git a/src/generic/armcm_timer.h b/src/generic/armcm_timer.h
new file mode 100644
index 00000000..5e118380
--- /dev/null
+++ b/src/generic/armcm_timer.h
@@ -0,0 +1,8 @@
+#ifndef __GENERIC_ARMCM_TIMER_H
+#define __GENERIC_ARMCM_TIMER_H
+
+#include <stdint.h> // uint32_t
+
+void udelay(uint32_t usecs);
+
+#endif // serial_irq.h