Reconstruct bl602 readme; move up_irq_save/restore declaration to common place

include/nuttx/arch.h

@@ -81,6 +81,7 @@
 #include <sched.h>
 
 #include <arch/arch.h>
+#include <arch/types.h>
 
 #include <nuttx/compiler.h>
 #include <nuttx/cache.h>
@@ -1353,6 +1354,39 @@ void up_irqinitialize(void);
 
 bool up_interrupt_context(void);
 
+/****************************************************************************
+ * Name: up_irq_save
+ *
+ * Description:
+ *   Save the current interrupt state and disable interrupts.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   Interrupt state prior to disabling interrupts.
+ *
+ ****************************************************************************/
+
+irqstate_t up_irq_save(void);
+
+/****************************************************************************
+ * Name: up_irq_restore
+ *
+ * Description:
+ *   Restore the previous irq state (i.e., the one previously
+ *   returned by up_irq_save())
+ *
+ * Input Parameters:
+ *   irqstate - The interrupt state to be restored.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void up_irq_restore(irqstate_t irqstate);
+
 /****************************************************************************
  * Name: up_enable_irq
  *