drivers: hwinfo: native: report reset cause

boards/native/native_sim/reboot_bottom.c

@@ -13,6 +13,7 @@
 #include <nsi_tasks.h>
 #include <nsi_tracing.h>
 #include <nsi_cmdline.h>
+#include <nsi_host_trampolines.h>
 
 static const char module[] = "native_sim_reboot";
 
@@ -63,6 +64,9 @@ void maybe_reboot(void)
 		nsi_exit(1);
 	}
 
+	/* Let's set an environment variable which the native_sim hw_info driver may check */
+	(void)nsi_host_setenv("NATIVE_SIM_RESET_CAUSE", "SOFTWARE", 1);
+
 	nsi_print_warning("%s: Restarting process.\n", module);
 
 	(void)execv("/proc/self/exe", argv);

drivers/hwinfo/hwinfo_native.c

@@ -4,6 +4,7 @@
  */
 
 #include <cmdline.h>
+#include <nsi_host_trampolines.h>
 #include <posix_native_task.h>
 #include <string.h>
 #include <zephyr/drivers/hwinfo.h>
@@ -13,6 +14,7 @@
 
 static uint32_t native_hwinfo_device_id;
 static bool native_hwinfo_device_id_set;
+static uint32_t native_hwinfo_reset_cause;
 
 ssize_t z_impl_hwinfo_get_device_id(uint8_t *buffer, size_t length)
 {
@@ -26,6 +28,27 @@ ssize_t z_impl_hwinfo_get_device_id(uint8_t *buffer, size_t length)
 	return length;
 }
 
+int z_impl_hwinfo_get_reset_cause(uint32_t *cause)
+{
+	*cause = native_hwinfo_reset_cause;
+
+	return 0;
+}
+
+int z_impl_hwinfo_clear_reset_cause(void)
+{
+	native_hwinfo_reset_cause = 0;
+
+	return 0;
+}
+
+int z_impl_hwinfo_get_supported_reset_cause(uint32_t *supported)
+{
+	*supported = RESET_POR | RESET_SOFTWARE;
+
+	return 0;
+}
+
 static void native_hwinfo_gethostid(void)
 {
 	if (!native_hwinfo_device_id_set) {
@@ -59,5 +82,30 @@ static void native_hwinfo_add_options(void)
 	native_add_command_line_opts(native_hwinfo_options);
 }
 
+static void native_hwinfo_get_reset_cause(void)
+{
+	/* If CONFIG_NATIVE_SIM_REBOOT was set, and a reboot was triggered, this
+	 * environment variable would be set. Otherwise it is not expected to
+	 * exist. Note this environment variable is not an stable API of any kind
+	 */
+	const char *cause = nsi_host_getenv("NATIVE_SIM_RESET_CAUSE");
+
+	if (!cause) {
+		/* Default to POR if not set */
+		native_hwinfo_reset_cause = RESET_POR;
+		return;
+	}
+
+	if (strcmp(cause, "SOFTWARE") == 0) {
+		native_hwinfo_reset_cause = RESET_SOFTWARE;
+	} else {
+		posix_print_warning("NATIVE_SIM_RESET_CAUSE (%s) set to an unknown reset cause, "
+				    "defaulting to POR\n",
+				    cause);
+		native_hwinfo_reset_cause = RESET_POR;
+	}
+}
+
 NATIVE_TASK(native_hwinfo_add_options, PRE_BOOT_1, 10);
 NATIVE_TASK(native_hwinfo_gethostid, PRE_BOOT_2, 10);
+NATIVE_TASK(native_hwinfo_get_reset_cause, PRE_BOOT_2, 10);

scripts/native_simulator/common/src/include/nsi_host_trampolines.h

@@ -27,13 +27,15 @@ int nsi_host_close(int fd);
 /* void nsi_host_exit (int status); Use nsi_exit() instead */
 void nsi_host_free(void *ptr);
 char *nsi_host_getcwd(char *buf, unsigned long size);
+char *nsi_host_getenv(const char *name);
 int nsi_host_isatty(int fd);
 void *nsi_host_malloc(unsigned long size);
 int nsi_host_open(const char *pathname, int flags);
 /* int nsi_host_printf (const char *fmt, ...); Use the nsi_tracing.h equivalents */
 long nsi_host_random(void);
 long nsi_host_read(int fd, void *buffer, unsigned long size);
 void *nsi_host_realloc(void *ptr, unsigned long size);
+int nsi_host_setenv(const char *name, const char *value, int overwrite);
 void nsi_host_srandom(unsigned int seed);
 char *nsi_host_strdup(const char *s);
 long nsi_host_write(int fd, const void *buffer, unsigned long size);

scripts/native_simulator/common/src/nsi_host_trampolines.c

@@ -31,6 +31,11 @@ char *nsi_host_getcwd(char *buf, unsigned long size)
 	return getcwd(buf, size);
 }
 
+char *nsi_host_getenv(const char *name)
+{
+	return getenv(name);
+}
+
 int nsi_host_isatty(int fd)
 {
 	return isatty(fd);
@@ -61,6 +66,11 @@ void *nsi_host_realloc(void *ptr, unsigned long size)
 	return realloc(ptr, size);
 }
 
+int nsi_host_setenv(const char *name, const char *value, int overwrite)
+{
+	return setenv(name, value, overwrite);
+}
+
 void nsi_host_srandom(unsigned int seed)
 {
 	srandom(seed);

tests/boards/native_sim/reset_hw_info/CMakeLists.txt

@@ -0,0 +1,9 @@
+# Copyright (c) 2025 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(native_reset_hw_info)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

tests/boards/native_sim/reset_hw_info/prj.conf

@@ -0,0 +1,6 @@
+# Copyright (c) 2025 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_REBOOT=y
+CONFIG_NATIVE_SIM_REBOOT=y
+CONFIG_HWINFO=y

tests/boards/native_sim/reset_hw_info/src/main.c

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <zephyr/drivers/hwinfo.h>
+#include <zephyr/sys/reboot.h>
+#include <nsi_main.h>
+
+int main(void)
+{
+	uint32_t cause;
+	int err;
+
+	err = hwinfo_get_reset_cause(&cause);
+	if (err != 0) {
+		posix_print_error_and_exit("hwinfo_get_reset_cause() failed %i\n", err);
+	}
+
+	if (cause == RESET_POR) {
+		printf("This seems like the first start => Resetting\n");
+		sys_reboot(SYS_REBOOT_WARM);
+	} else if (cause == RESET_SOFTWARE) {
+		printf("Booted after SOFTWARE reset => we are done\n");
+	}
+	nsi_exit(0);
+}

tests/boards/native_sim/reset_hw_info/testcase.yaml

@@ -0,0 +1,16 @@
+tests:
+  boards.native_sim.reset_hw_info:
+    platform_allow:
+      - native_sim
+      - native_sim/native/64
+    integration_platforms:
+      - native_sim
+    harness: console
+    harness_config:
+      type: multi_line
+      ordered: true
+      regex:
+        - "(.*)Booting Zephyr OS build(.*)"
+        - "This seems like the first start => Resetting"
+        - "(.*)Booting Zephyr OS build(.*)"
+        - "Booted after SOFTWARE reset => we are done"