drm: Use state helper instead of plane state pointer in atomic_check

Many drivers reference the plane->state pointer in order to get the
current plane state in their atomic_check hook, which would be the old
plane state in the global atomic state since _swap_state hasn't happened
when atomic_check is run.

Use the drm_atomic_get_old_plane_state helper to get that state to make
it more obvious.

This was made using the coccinelle script below:

@ plane_atomic_func @
identifier helpers;
identifier func;
@@

static struct drm_plane_helper_funcs helpers = {
	...,
	.atomic_check = func,
	...,
};

@ replaces_old_state @
identifier plane_atomic_func.func;
identifier plane, state, plane_state;
@@

 func(struct drm_plane *plane, struct drm_atomic_state *state) {
 	...
-	struct drm_plane_state *plane_state = plane->state;
+	struct drm_plane_state *plane_state = drm_atomic_get_old_plane_state(state, plane);
 	...
 }

@@
identifier plane_atomic_func.func;
identifier plane, state, plane_state;
@@

 func(struct drm_plane *plane, struct drm_atomic_state *state) {
 	struct drm_plane_state *plane_state = drm_atomic_get_old_plane_state(state, plane);
 	<...
-	plane->state
+	plane_state
 	...>
 }

@ adds_old_state @
identifier plane_atomic_func.func;
identifier plane, state;
@@

 func(struct drm_plane *plane, struct drm_atomic_state *state) {
+	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	<...
-	plane->state
+	old_plane_state
 	...>
 }

@ include depends on adds_old_state || replaces_old_state @
@@

 #include <drm/drm_atomic.h>

@ no_include depends on !include && (adds_old_state || replaces_old_state) @
@@

+ #include <drm/drm_atomic.h>
  #include <drm/...>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210219120032.260676-6-maxime@cerno.tech

drivers/gpu/drm/imx/ipuv3-plane.c

@@ -341,7 +341,8 @@ static int ipu_plane_atomic_check(struct drm_plane *plane,
 {
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state,
 									   plane);
-	struct drm_plane_state *old_state = plane->state;
+	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,
+									   plane);
 	struct drm_crtc_state *crtc_state;
 	struct device *dev = plane->dev->dev;
 	struct drm_framebuffer *fb = new_state->fb;

drivers/gpu/drm/ingenic/ingenic-drm-drv.c

@@ -362,11 +362,13 @@ static void ingenic_drm_crtc_atomic_flush(struct drm_crtc *crtc,
 static int ingenic_drm_plane_atomic_check(struct drm_plane *plane,
 					  struct drm_atomic_state *state)
 {
+	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state,
+										 plane);
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state,
 										 plane);
 	struct ingenic_drm *priv = drm_device_get_priv(plane->dev);
 	struct drm_crtc_state *crtc_state;
-	struct drm_crtc *crtc = new_plane_state->crtc ?: plane->state->crtc;
+	struct drm_crtc *crtc = new_plane_state->crtc ?: old_plane_state->crtc;
 	int ret;
 
 	if (!crtc)
@@ -400,12 +402,12 @@ static int ingenic_drm_plane_atomic_check(struct drm_plane *plane,
 	 * its position, size or depth.
 	 */
 	if (priv->soc_info->has_osd &&
-	    (!plane->state->fb || !new_plane_state->fb ||
-	     plane->state->crtc_x != new_plane_state->crtc_x ||
-	     plane->state->crtc_y != new_plane_state->crtc_y ||
-	     plane->state->crtc_w != new_plane_state->crtc_w ||
-	     plane->state->crtc_h != new_plane_state->crtc_h ||
-	     plane->state->fb->format->format != new_plane_state->fb->format->format))
+	    (!old_plane_state->fb || !new_plane_state->fb ||
+	     old_plane_state->crtc_x != new_plane_state->crtc_x ||
+	     old_plane_state->crtc_y != new_plane_state->crtc_y ||
+	     old_plane_state->crtc_w != new_plane_state->crtc_w ||
+	     old_plane_state->crtc_h != new_plane_state->crtc_h ||
+	     old_plane_state->fb->format->format != new_plane_state->fb->format->format))
 		crtc_state->mode_changed = true;
 
 	return 0;

drivers/gpu/drm/ingenic/ingenic-ipu.c

@@ -516,11 +516,13 @@ static void ingenic_ipu_plane_atomic_update(struct drm_plane *plane,
 static int ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
 					  struct drm_atomic_state *state)
 {
+	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state,
+										 plane);
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state,
 										 plane);
 	unsigned int num_w, denom_w, num_h, denom_h, xres, yres, max_w, max_h;
 	struct ingenic_ipu *ipu = plane_to_ingenic_ipu(plane);
-	struct drm_crtc *crtc = new_plane_state->crtc ?: plane->state->crtc;
+	struct drm_crtc *crtc = new_plane_state->crtc ?: old_plane_state->crtc;
 	struct drm_crtc_state *crtc_state;
 
 	if (!crtc)
@@ -531,7 +533,7 @@ static int ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
 		return -EINVAL;
 
 	/* Request a full modeset if we are enabling or disabling the IPU. */
-	if (!plane->state->crtc ^ !new_plane_state->crtc)
+	if (!old_plane_state->crtc ^ !new_plane_state->crtc)
 		crtc_state->mode_changed = true;
 
 	if (!new_plane_state->crtc ||
@@ -552,7 +554,7 @@ static int ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
 	if (((new_plane_state->src_w >> 16) & 1) || (new_plane_state->crtc_w & 1))
 		return -EINVAL;
 
-	if (!osd_changed(new_plane_state, plane->state))
+	if (!osd_changed(new_plane_state, old_plane_state))
 		return 0;
 
 	crtc_state->mode_changed = true;

drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c

@@ -406,12 +406,14 @@ static int mdp5_plane_atomic_check_with_state(struct drm_crtc_state *crtc_state,
 static int mdp5_plane_atomic_check(struct drm_plane *plane,
 				   struct drm_atomic_state *state)
 {
+	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state,
+										 plane);
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state,
 										 plane);
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *crtc_state;
 
-	crtc = new_plane_state->crtc ? new_plane_state->crtc : plane->state->crtc;
+	crtc = new_plane_state->crtc ? new_plane_state->crtc : old_plane_state->crtc;
 	if (!crtc)
 		return 0;
 

drivers/gpu/drm/tilcdc/tilcdc_plane.c

@@ -26,7 +26,8 @@ static int tilcdc_plane_atomic_check(struct drm_plane *plane,
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state,
 									   plane);
 	struct drm_crtc_state *crtc_state;
-	struct drm_plane_state *old_state = plane->state;
+	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,
+									   plane);
 	unsigned int pitch;
 
 	if (!new_state->crtc)