kunit: Add APIs for managing devices

Tests for drivers often require a struct device to pass to other
functions. While it's possible to create these with
root_device_register(), or to use something like a platform device, this
is both a misuse of those APIs, and can be difficult to clean up after,
for example, a failed assertion.

Add some KUnit-specific functions for registering and unregistering a
struct device:
- kunit_device_register()
- kunit_device_register_with_driver()
- kunit_device_unregister()

These helpers allocate a on a 'kunit' bus which will either probe the
driver passed in (kunit_device_register_with_driver), or will create a
stub driver (kunit_device_register) which is cleaned up on test shutdown.

Devices are automatically unregistered on test shutdown, but can be
manually unregistered earlier with kunit_device_unregister() in order
to, for example, test device release code.

Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 088489856db8..14a77b2d702a 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -19,6 +19,7 @@
 #include <linux/sched.h>
 
 #include "debugfs.h"
+#include "device-impl.h"
 #include "hooks-impl.h"
 #include "string-stream.h"
 #include "try-catch-impl.h"
@@ -900,6 +901,8 @@ static int __init kunit_init(void)
 	kunit_install_hooks();
 
 	kunit_debugfs_init();
+
+	kunit_bus_init();
 #ifdef CONFIG_MODULES
 	return register_module_notifier(&kunit_mod_nb);
 #else