Unable to reboot with TF-M

[caspar.friedrich]

Hi,

when I build a firmware with TF-M enabled the device gets stuck after a call to sys_reboot(...) no matter if I use the shell or call the function somewhere else in my code.

Regards

Caspar

[Øyvind]

Hi Caspar, can you please provide information on what version of NCS you are using. What sample are you running? I will need some more information in order to recreate the issue.

Thanks!
Kind regards,
Øyvind

[caspar.friedrich]

Just tried with the shell_module example. I added CONFIG_BUILD_WITH_TFM=y to prj.conf and copied nrf9160dk_nrf9160ns.overlay over to disable UART1. If I no try to "kernel reboot [cold|warm]" the device gets stuck.

[Øyvind]

Hello, 

Did you try with the "TF-M Hello World" sample?

Kind regards,
Øyvind

[caspar.friedrich]

Just did. added the following:

diff --git a/samples/tfm/tfm_hello_world/src/main.c b/samples/tfm/tfm_hello_world/src/main.c
index 4ca26a9f..804d2339 100644
--- a/samples/tfm/tfm_hello_world/src/main.c
+++ b/samples/tfm/tfm_hello_world/src/main.c
@@ -11,6 +11,8 @@
 #include <tfm_ns_interface.h>
 #include "psa/crypto.h"

+#include <power/reboot.h>
+
 #define HELLO_PATTERN "Hello World! %s\n"

 void main(void)
@@ -47,4 +49,8 @@ void main(void)
 					i % 16 == 15 ? "\n" : "");
 		}
 	}
+
+	printk("about to reboot\n");
+	k_sleep(K_SECONDS(3));
+	sys_reboot(SYS_REBOOT_COLD);
 }

gets stuck after printing about to reboot.

[Øyvind]

Hi, 

I've added the same to tfm_hello_world and seeing the same. Will talk to our developers and get back to you within tomorrow. 

Kind regards,
Øyvind

[Øyvind]

Hi Caspar, 
The non-secure application is by default not allowed to reset. That is why, when using TF-M, you need to use the TF-M API to reset the device. I tested with tfm_platform_system_reset() from tfm_platform_api.h and that worked as intended.

In future release the sys_reboot() will include TF-M reset function.

Kind regards,
Øyvind

[caspar.friedrich]

Oh, wow... Didn't see that. Thanks. That worked.