drm/tests: helpers: Allow to pass a custom drm_driver

Some tests will need to provide their own drm_driver instead of relying
on the dumb one in the helpers, so let's create a helper that allows to
do so.
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20221123-rpi-kunit-tests-v3-11-4615a663a84a@cerno.techSigned-off-by: Maxime Ripard <maxime@cerno.tech>

drivers/gpu/drm/tests/drm_kunit_helpers.c

@@ -82,20 +82,15 @@ void drm_kunit_helper_free_device(struct kunit *test, struct device *dev)
 EXPORT_SYMBOL_GPL(drm_kunit_helper_free_device);
 
 struct drm_device *
-__drm_kunit_helper_alloc_drm_device(struct kunit *test, struct device *dev,
-				    size_t size, size_t offset,
-				    u32 features)
+__drm_kunit_helper_alloc_drm_device_with_driver(struct kunit *test,
+						struct device *dev,
+						size_t size, size_t offset,
+						const struct drm_driver *driver)
 {
 	struct drm_device *drm;
-	struct drm_driver *driver;
 	void *container;
 	int ret;
 
-	driver = kunit_kzalloc(test, sizeof(*driver), GFP_KERNEL);
-	if (!driver)
-		return ERR_PTR(-ENOMEM);
-
-	driver->driver_features = features;
 	container = __devm_drm_dev_alloc(dev, driver, size, offset);
 	if (IS_ERR(container))
 		return ERR_CAST(container);
@@ -109,7 +104,7 @@ __drm_kunit_helper_alloc_drm_device(struct kunit *test, struct device *dev,
 
 	return drm;
 }
-EXPORT_SYMBOL_GPL(__drm_kunit_helper_alloc_drm_device);
+EXPORT_SYMBOL_GPL(__drm_kunit_helper_alloc_drm_device_with_driver);
 
 MODULE_AUTHOR("Maxime Ripard <maxime@cerno.tech>");
 MODULE_LICENSE("GPL");

include/drm/drm_kunit_helpers.h

@@ -3,6 +3,8 @@
 #ifndef DRM_KUNIT_HELPERS_H_
 #define DRM_KUNIT_HELPERS_H_
 
+#include <kunit/test.h>
+
 struct drm_device;
 struct kunit;
 
@@ -10,9 +12,54 @@ struct device *drm_kunit_helper_alloc_device(struct kunit *test);
 void drm_kunit_helper_free_device(struct kunit *test, struct device *dev);
 
 struct drm_device *
-__drm_kunit_helper_alloc_drm_device(struct kunit *test, struct device *dev,
+__drm_kunit_helper_alloc_drm_device_with_driver(struct kunit *test,
+						struct device *dev,
+						size_t size, size_t offset,
+						const struct drm_driver *driver);
+
+/**
+ * drm_kunit_helper_alloc_drm_device_with_driver - Allocates a mock DRM device for KUnit tests
+ * @_test: The test context object
+ * @_dev: The parent device object
+ * @_type: the type of the struct which contains struct &drm_device
+ * @_member: the name of the &drm_device within @_type.
+ * @_drv: Mocked DRM device driver features
+ *
+ * This function creates a struct &drm_device from @_dev and @_drv.
+ *
+ * @_dev should be allocated using drm_kunit_helper_alloc_device().
+ *
+ * The driver is tied to the @_test context and will get cleaned at the
+ * end of the test. The drm_device is allocated through
+ * devm_drm_dev_alloc() and will thus be freed through a device-managed
+ * resource.
+ *
+ * Returns:
+ * A pointer to the new drm_device, or an ERR_PTR() otherwise.
+ */
+#define drm_kunit_helper_alloc_drm_device_with_driver(_test, _dev, _type, _member, _drv)	\
+	((_type *)__drm_kunit_helper_alloc_drm_device_with_driver(_test, _dev,			\
+						       sizeof(_type),				\
+						       offsetof(_type, _member),		\
+						       _drv))
+
+static inline struct drm_device *
+__drm_kunit_helper_alloc_drm_device(struct kunit *test,
+				    struct device *dev,
 				    size_t size, size_t offset,
-				    u32 features);
+				    u32 features)
+{
+	struct drm_driver *driver;
+
+	driver = kunit_kzalloc(test, sizeof(*driver), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, driver);
+
+	driver->driver_features = features;
+
+	return __drm_kunit_helper_alloc_drm_device_with_driver(test, dev,
+							       size, offset,
+							       driver);
+}
 
 /**
  * drm_kunit_helper_alloc_drm_device - Allocates a mock DRM device for KUnit tests