drm/mipi-dbi: Move drm_dev_{enter, exit}() out from fb_dirty functions

Call drm_dev_enter() and drm_dev_exit() in the outer-most callbacks
of the modesetting pipeline. If drm_dev_enter() fails, the driver can
thus avoid unnecessary work.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org> # drm/tiny/mi0283qt
Link: https://patchwork.freedesktop.org/patch/msgid/20221202125644.7917-9-tzimmermann@suse.de

drivers/gpu/drm/drm_mipi_dbi.c

@@ -259,13 +259,10 @@ static void mipi_dbi_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
 	unsigned int width = rect->x2 - rect->x1;
 	struct mipi_dbi *dbi = &dbidev->dbi;
 	bool swap = dbi->swap_bytes;
-	int idx, ret = 0;
+	int ret = 0;
 	bool full;
 	void *tr;
 
-	if (!drm_dev_enter(fb->dev, &idx))
-		return;
-
 	full = width == fb->width && height == fb->height;
 
 	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
@@ -288,8 +285,6 @@ static void mipi_dbi_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
 err_msg:
 	if (ret)
 		drm_err_once(fb->dev, "Failed to update display %d\n", ret);
-
-	drm_dev_exit(idx);
 }
 
 /**
@@ -325,6 +320,7 @@ void mipi_dbi_pipe_update(struct drm_simple_display_pipe *pipe,
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
 	struct drm_framebuffer *fb = state->fb;
 	struct drm_rect rect;
+	int idx;
 
 	if (!pipe->crtc.state->active)
 		return;
@@ -332,8 +328,13 @@ void mipi_dbi_pipe_update(struct drm_simple_display_pipe *pipe,
 	if (WARN_ON(!fb))
 		return;
 
+	if (!drm_dev_enter(fb->dev, &idx))
+		return;
+
 	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 		mipi_dbi_fb_dirty(&shadow_plane_state->data[0], fb, &rect);
+
+	drm_dev_exit(idx);
 }
 EXPORT_SYMBOL(mipi_dbi_pipe_update);
 

drivers/gpu/drm/tiny/ili9225.c

@@ -87,13 +87,10 @@ static void ili9225_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
 	bool swap = dbi->swap_bytes;
 	u16 x_start, y_start;
 	u16 x1, x2, y1, y2;
-	int idx, ret = 0;
+	int ret = 0;
 	bool full;
 	void *tr;
 
-	if (!drm_dev_enter(fb->dev, &idx))
-		return;
-
 	full = width == fb->width && height == fb->height;
 
 	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
@@ -156,8 +153,6 @@ static void ili9225_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
 err_msg:
 	if (ret)
 		dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
-
-	drm_dev_exit(idx);
 }
 
 static void ili9225_pipe_update(struct drm_simple_display_pipe *pipe,
@@ -167,12 +162,18 @@ static void ili9225_pipe_update(struct drm_simple_display_pipe *pipe,
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
 	struct drm_framebuffer *fb = state->fb;
 	struct drm_rect rect;
+	int idx;
 
 	if (!pipe->crtc.state->active)
 		return;
 
+	if (!drm_dev_enter(fb->dev, &idx))
+		return;
+
 	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 		ili9225_fb_dirty(&shadow_plane_state->data[0], fb, &rect);
+
+	drm_dev_exit(idx);
 }
 
 static void ili9225_pipe_enable(struct drm_simple_display_pipe *pipe,

drivers/gpu/drm/tiny/st7586.c

@@ -113,10 +113,7 @@ static void st7586_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
 {
 	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
 	struct mipi_dbi *dbi = &dbidev->dbi;
-	int start, end, idx, ret = 0;
-
-	if (!drm_dev_enter(fb->dev, &idx))
-		return;
+	int start, end, ret = 0;
 
 	/* 3 pixels per byte, so grow clip to nearest multiple of 3 */
 	rect->x1 = rounddown(rect->x1, 3);
@@ -145,8 +142,6 @@ static void st7586_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
 err_msg:
 	if (ret)
 		dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
-
-	drm_dev_exit(idx);
 }
 
 static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
@@ -156,12 +151,18 @@ static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
 	struct drm_framebuffer *fb = state->fb;
 	struct drm_rect rect;
+	int idx;
 
 	if (!pipe->crtc.state->active)
 		return;
 
+	if (!drm_dev_enter(fb->dev, &idx))
+		return;
+
 	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 		st7586_fb_dirty(&shadow_plane_state->data[0], fb, &rect);
+
+	drm_dev_exit(idx);
 }
 
 static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,