drm/vc4: vec: Check for VEC output constraints

The VEC can accept pretty much any relatively reasonable mode, but still
has a bunch of constraints to meet.

Let's create an atomic_check() implementation that will make sure we
don't end up accepting a non-functional mode.

Acked-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
Tested-by: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
Acked-in-principle-or-something-like-that-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v10-16-256dad125326@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

diff --git a/drivers/gpu/drm/vc4/vc4_vec.c b/drivers/gpu/drm/vc4/vc4_vec.c
index 90e375a..bfa8a58 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_vec.c
+++ b/drivers/gpu/drm/vc4/vc4_vec.c
@@ -453,6 +453,7 @@ static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder,
                                        struct drm_crtc_state *crtc_state,
                                        struct drm_connector_state *conn_state)
 {
+       const struct drm_display_mode *mode = &crtc_state->adjusted_mode;
        const struct vc4_vec_tv_mode *vec_mode;
 
        vec_mode = &vc4_vec_tv_modes[conn_state->tv.legacy_mode];
@@ -461,6 +462,55 @@ static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder,
            !drm_mode_equal(vec_mode->mode, &crtc_state->adjusted_mode))
                return -EINVAL;
 
+       if (mode->crtc_hdisplay % 4)
+               return -EINVAL;
+
+       if (!(mode->crtc_hsync_end - mode->crtc_hsync_start))
+               return -EINVAL;
+
+       switch (mode->htotal) {
+       /* NTSC */
+       case 858:
+               if (mode->crtc_vtotal > 262)
+                       return -EINVAL;
+
+               if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 253)
+                       return -EINVAL;
+
+               if (!(mode->crtc_vsync_start - mode->crtc_vdisplay))
+                       return -EINVAL;
+
+               if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3)
+                       return -EINVAL;
+
+               if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 4)
+                       return -EINVAL;
+
+               break;
+
+       /* PAL/SECAM */
+       case 864:
+               if (mode->crtc_vtotal > 312)
+                       return -EINVAL;
+
+               if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 305)
+                       return -EINVAL;
+
+               if (!(mode->crtc_vsync_start - mode->crtc_vdisplay))
+                       return -EINVAL;
+
+               if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3)
+                       return -EINVAL;
+
+               if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 2)
+                       return -EINVAL;
+
+               break;
+
+       default:
+               return -EINVAL;
+       }
+
        return 0;
 }