From e931d3b9cda723d63bf352ca866dc499d8df21f5 Mon Sep 17 00:00:00 2001
From: px4dev <px4@purgatory.org>
Date: Sat, 3 Aug 2013 22:35:18 -0700
Subject: [PATCH] Add an option to the systemreset() call and to the reboot
 command (-b) to reboot into the bootloader.

The system will remain in the bootloader until it's reset, or until an upload is completed.
---
 src/modules/commander/state_machine_helper.c |  2 +-
 src/modules/systemlib/systemlib.c            | 12 +++++++++++-
 src/modules/systemlib/systemlib.h            |  2 +-
 src/systemcmds/reboot/reboot.c               | 19 ++++++++++++++++++-
 4 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/modules/commander/state_machine_helper.c b/src/modules/commander/state_machine_helper.c
index c264787852..9b6527c330 100644
--- a/src/modules/commander/state_machine_helper.c
+++ b/src/modules/commander/state_machine_helper.c
@@ -141,7 +141,7 @@ int do_state_update(int status_pub, struct vehicle_status_s *current_status, con
 			current_status->flag_system_armed = false;
 			mavlink_log_critical(mavlink_fd, "REBOOTING SYSTEM");
 			usleep(500000);
-			systemreset();
+			systemreset(false);
 			/* SPECIAL CASE: NEVER RETURNS FROM THIS FUNCTION CALL */
 
 		} else {
diff --git a/src/modules/systemlib/systemlib.c b/src/modules/systemlib/systemlib.c
index 96276b56a3..57a751e1c3 100644
--- a/src/modules/systemlib/systemlib.c
+++ b/src/modules/systemlib/systemlib.c
@@ -50,9 +50,19 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#include <stm32_pwr.h>
+
 #include "systemlib.h"
 
-__EXPORT extern void systemreset(void) {
+void
+systemreset(bool to_bootloader)
+{
+	if (to_bootloader) {
+		stm32_pwr_enablebkp();
+
+		/* XXX wow, this is evil - write a magic number into backup register zero */
+		*(uint32_t *)0x40002850 = 0xb007b007;
+	}
 	up_systemreset();
 }
 
diff --git a/src/modules/systemlib/systemlib.h b/src/modules/systemlib/systemlib.h
index 77fdfe08af..3728f20672 100644
--- a/src/modules/systemlib/systemlib.h
+++ b/src/modules/systemlib/systemlib.h
@@ -45,7 +45,7 @@
 __BEGIN_DECLS
 
 /** Reboots the board */
-__EXPORT void systemreset(void) noreturn_function;
+__EXPORT void systemreset(bool to_bootloader) noreturn_function;
 
 /** Sends SIGUSR1 to all processes */
 __EXPORT void killall(void);
diff --git a/src/systemcmds/reboot/reboot.c b/src/systemcmds/reboot/reboot.c
index 0fd1e27244..91a2c2eb8d 100644
--- a/src/systemcmds/reboot/reboot.c
+++ b/src/systemcmds/reboot/reboot.c
@@ -40,14 +40,31 @@
 #include <nuttx/config.h>
 #include <unistd.h>
 #include <stdio.h>
+#include <getopt.h>
 
 #include <systemlib/systemlib.h>
+#include <systemlib/err.h>
 
 __EXPORT int reboot_main(int argc, char *argv[]);
 
 int reboot_main(int argc, char *argv[])
 {
-	systemreset();
+	int ch;
+	bool to_bootloader = false;
+
+	while ((ch = getopt(argc, argv, "b")) != -1) {
+		switch (ch) {
+		case 'b':
+			to_bootloader = true;
+			break;
+		default:
+			errx(1, "usage: reboot [-b]\n"
+				"   -b   reboot into the bootloader");
+
+		}
+	}
+
+	systemreset(to_bootloader);
 }