STM32 option to disable sleep to prevent disconnection of debugger

ChangeLog

@@ -4683,3 +4683,8 @@
 	* arch/arm/src/kinetis/kinetis_pin.c and arch/arm/src/kinetis/kinetis_internal.h:
 	  The Kinetis GPIO logic had some of the same issues as did the
 	  Kinetis L (2013-5-6).
+	* arch/arm/src/stm32/stm32_idle.c: Add an option to conditionally disable
+	  the "wfi" sleep mode.  This is needed with certain JTAG debuggers to
+	  to prevent the debug session from begin disconnected.  From Ken Pettit
+	  (2013-5-7).
+

arch/arm/src/stm32/Kconfig

@@ -861,6 +861,15 @@ config STM32_JTAG_SW_ENABLE
 
 endchoice
 
+config STM32_DISABLE_IDLE_SLEEP_DURING_DEBUG
+	bool "Disable IDLE Sleep (WFI) in debug mode"
+	default n
+	---help---
+		In debug configuration, disables the WFI instruction in the IDLE loop
+		to prevent the JTAG from disconnecting.  With some JTAG debuggers, such
+		as the ST-LINK2 with OpenOCD, if the ARM is put to sleep via the WFI
+		instruction, the debugger will disconnect, terminating the debug session.
+
 config STM32_FORCEPOWER
 	bool "Force power"
 	default n

arch/arm/src/stm32/stm32_idle.c

@@ -202,10 +202,12 @@ void up_idle(void)
    */
 
 #if !defined(CONFIG_STM32_CONNECTIVITYLINE) || !defined(CONFIG_STM32_ETHMAC)
+#if !(defined(CONFIG_DEBUG_SYMBOLS) && defined(CONFIG_STM32_DISABLE_IDLE_SLEEP_DURING_DEBUG))
   BEGIN_IDLE();
   asm("WFI");
   END_IDLE();
 #endif
 #endif
+#endif
 }