drm/vc4: crtc: Introduce a lower-level crtc init helper

The current vc4_crtc_init() helper assumes that we will be using
hardware planes and calls vc4_plane_init().

While it's a reasonable assumption, we'll want to mock the plane and
thus provide our own. Let's create a helper that will take the plane as
an argument.
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Link: https://lore.kernel.org/r/20221123-rpi-kunit-tests-v3-14-4615a663a84a@cerno.techSigned-off-by: Maxime Ripard <maxime@cerno.tech>

drivers/gpu/drm/vc4/vc4_crtc.c

@@ -1286,31 +1286,38 @@ static void vc4_set_crtc_possible_masks(struct drm_device *drm,
 	}
 }
 
-int vc4_crtc_init(struct drm_device *drm, struct platform_device *pdev,
-		  struct vc4_crtc *vc4_crtc,
-		  const struct vc4_crtc_data *data,
-		  const struct drm_crtc_funcs *crtc_funcs,
-		  const struct drm_crtc_helper_funcs *crtc_helper_funcs,
-		  bool feeds_txp)
+/**
+ * __vc4_crtc_init - Initializes a CRTC
+ * @drm: DRM Device
+ * @pdev: CRTC Platform Device
+ * @vc4_crtc: CRTC Object to Initialize
+ * @data: Configuration data associated with this CRTC
+ * @primary_plane: Primary plane for CRTC
+ * @crtc_funcs: Callbacks for the new CRTC
+ * @crtc_helper_funcs: Helper Callbacks for the new CRTC
+ * @feeds_txp: Is this CRTC connected to the TXP?
+ *
+ * Initializes our private CRTC structure. This function is mostly
+ * relevant for KUnit testing, all other users should use
+ * vc4_crtc_init() instead.
+ *
+ * Returns:
+ * 0 on success, a negative error code on failure.
+ */
+int __vc4_crtc_init(struct drm_device *drm,
+		    struct platform_device *pdev,
+		    struct vc4_crtc *vc4_crtc,
+		    const struct vc4_crtc_data *data,
+		    struct drm_plane *primary_plane,
+		    const struct drm_crtc_funcs *crtc_funcs,
+		    const struct drm_crtc_helper_funcs *crtc_helper_funcs,
+		    bool feeds_txp)
 {
 	struct vc4_dev *vc4 = to_vc4_dev(drm);
 	struct drm_crtc *crtc = &vc4_crtc->base;
-	struct drm_plane *primary_plane;
 	unsigned int i;
 	int ret;
 
-	/* For now, we create just the primary and the legacy cursor
-	 * planes.  We should be able to stack more planes on easily,
-	 * but to do that we would need to compute the bandwidth
-	 * requirement of the plane configuration, and reject ones
-	 * that will take too much.
-	 */
-	primary_plane = vc4_plane_init(drm, DRM_PLANE_TYPE_PRIMARY, 0);
-	if (IS_ERR(primary_plane)) {
-		dev_err(drm->dev, "failed to construct primary plane\n");
-		return PTR_ERR(primary_plane);
-	}
-
 	vc4_crtc->data = data;
 	vc4_crtc->pdev = pdev;
 	vc4_crtc->feeds_txp = feeds_txp;
@@ -1342,6 +1349,31 @@ int vc4_crtc_init(struct drm_device *drm, struct platform_device *pdev,
 	return 0;
 }
 
+int vc4_crtc_init(struct drm_device *drm, struct platform_device *pdev,
+		  struct vc4_crtc *vc4_crtc,
+		  const struct vc4_crtc_data *data,
+		  const struct drm_crtc_funcs *crtc_funcs,
+		  const struct drm_crtc_helper_funcs *crtc_helper_funcs,
+		  bool feeds_txp)
+{
+	struct drm_plane *primary_plane;
+
+	/* For now, we create just the primary and the legacy cursor
+	 * planes.  We should be able to stack more planes on easily,
+	 * but to do that we would need to compute the bandwidth
+	 * requirement of the plane configuration, and reject ones
+	 * that will take too much.
+	 */
+	primary_plane = vc4_plane_init(drm, DRM_PLANE_TYPE_PRIMARY, 0);
+	if (IS_ERR(primary_plane)) {
+		dev_err(drm->dev, "failed to construct primary plane\n");
+		return PTR_ERR(primary_plane);
+	}
+
+	return __vc4_crtc_init(drm, pdev, vc4_crtc, data, primary_plane,
+			       crtc_funcs, crtc_helper_funcs, feeds_txp);
+}
+
 static int vc4_crtc_bind(struct device *dev, struct device *master, void *data)
 {
 	struct platform_device *pdev = to_platform_device(dev);

drivers/gpu/drm/vc4/vc4_drv.h

@@ -888,6 +888,12 @@ int vc4_bo_debugfs_init(struct drm_minor *minor);
 /* vc4_crtc.c */
 extern struct platform_driver vc4_crtc_driver;
 int vc4_crtc_disable_at_boot(struct drm_crtc *crtc);
+int __vc4_crtc_init(struct drm_device *drm, struct platform_device *pdev,
+		    struct vc4_crtc *vc4_crtc, const struct vc4_crtc_data *data,
+		    struct drm_plane *primary_plane,
+		    const struct drm_crtc_funcs *crtc_funcs,
+		    const struct drm_crtc_helper_funcs *crtc_helper_funcs,
+		    bool feeds_txp);
 int vc4_crtc_init(struct drm_device *drm, struct platform_device *pdev,
 		  struct vc4_crtc *vc4_crtc, const struct vc4_crtc_data *data,
 		  const struct drm_crtc_funcs *crtc_funcs,