[PATCH v1 2/3] drm/tegra: plane: Implement zPos plane property for older Tegra's

From: Dmitry Osipenko
Date: Thu May 03 2018 - 20:09:40 EST


Older Tegra's do not support planes z position handling in hardware,
but HW provides knobs for zPos implementation in software.

Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/gpu/drm/tegra/dc.c | 134 ++++++++++++++++-------
drivers/gpu/drm/tegra/plane.c | 193 ++++++++++++++++++++++++----------
drivers/gpu/drm/tegra/plane.h | 13 ++-
3 files changed, 244 insertions(+), 96 deletions(-)

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 2e81142281c3..ba5481cd470d 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -162,29 +162,90 @@ static void tegra_plane_setup_blending_legacy(struct tegra_plane *plane)
u32 foreground = BLEND_WEIGHT1(255) | BLEND_WEIGHT0(255) |
BLEND_COLOR_KEY_NONE;
u32 blendnokey = BLEND_WEIGHT1(255) | BLEND_WEIGHT0(255);
+ u32 blending[2];
struct tegra_plane_state *state;
unsigned int i;

+ /* disable blending for non-overlapping case */
+ tegra_plane_writel(plane, blendnokey, DC_WIN_BLEND_NOKEY);
+ tegra_plane_writel(plane, foreground, DC_WIN_BLEND_1WIN);
+
state = to_tegra_plane_state(plane->base.state);

- /* alpha contribution is 1 minus sum of overlapping windows */
- for (i = 0; i < 3; i++) {
- if (state->dependent[i])
- background[i] |= BLEND_CONTROL_DEPENDENT;
- }
+ if (state->opaque) {
+ /*
+ * Since custom fix-weight blending isn't utilized and weight
+ * of top window is set to max, we can enforce dependent
+ * blending which in this case results in transparent bottom
+ * window if top window is opaque and if top window enables
+ * alpha blending, then bottom window is getting alpha value
+ * of 1 minus the sum of alpha components of the overlapping
+ * plane.
+ */
+ background[0] |= BLEND_CONTROL_DEPENDENT;
+ background[1] |= BLEND_CONTROL_DEPENDENT;

- /* enable alpha blending if pixel format has an alpha component */
- if (!state->opaque)
+ /*
+ * The region where three windows overlap is the intersection
+ * of the two regions where two windows overlap. It contributes
+ * to the area if all of the windows on top of it have an alpha
+ * component.
+ */
+ switch (state->base.normalized_zpos) {
+ case 0:
+ if (state->blending[0].alpha &&
+ state->blending[1].alpha)
+ background[2] |= BLEND_CONTROL_DEPENDENT;
+ break;
+
+ case 1:
+ background[2] |= BLEND_CONTROL_DEPENDENT;
+ break;
+ }
+ } else {
+ /*
+ * Enable alpha blending if pixel format has an alpha
+ * component.
+ */
foreground |= BLEND_CONTROL_ALPHA;

- /*
- * Disable blending and assume Window A is the bottom-most window,
- * Window C is the top-most window and Window B is in the middle.
- */
- tegra_plane_writel(plane, blendnokey, DC_WIN_BLEND_NOKEY);
- tegra_plane_writel(plane, foreground, DC_WIN_BLEND_1WIN);
+ /*
+ * If any of the windows on top of this window is opaque, it
+ * will completely conceal this window within that area. If
+ * top window has an alpha component, it is blended over the
+ * bottom window.
+ */
+ for (i = 0; i < 2; i++) {
+ if (state->blending[i].alpha &&
+ state->blending[i].top)
+ background[i] |= BLEND_CONTROL_DEPENDENT;
+ }
+
+ switch (state->base.normalized_zpos) {
+ case 0:
+ if (state->blending[0].alpha &&
+ state->blending[1].alpha)
+ background[2] |= BLEND_CONTROL_DEPENDENT;
+ break;
+
+ case 1:
+ /*
+ * When both middle and topmost windows have an alpha,
+ * these windows a mixed together and then the result
+ * is blended over the bottom window.
+ */
+ if ((state->blending[0].alpha &&
+ state->blending[0].top))
+ background[2] |= BLEND_CONTROL_ALPHA;

- switch (plane->index) {
+ if (state->blending[1].alpha &&
+ state->blending[1].top)
+ background[2] |= BLEND_CONTROL_ALPHA;
+ break;
+ }
+ }
+
+ switch (state->base.normalized_zpos) {
case 0:
tegra_plane_writel(plane, background[0], DC_WIN_BLEND_2WIN_X);
tegra_plane_writel(plane, background[1], DC_WIN_BLEND_2WIN_Y);
@@ -192,8 +253,21 @@ static void tegra_plane_setup_blending_legacy(struct tegra_plane *plane)
break;

case 1:
- tegra_plane_writel(plane, foreground, DC_WIN_BLEND_2WIN_X);
- tegra_plane_writel(plane, background[1], DC_WIN_BLEND_2WIN_Y);
+ /*
+ * If window B / C is topmost, then X / Y registers are
+ * matching the order of blending[...] state indices,
+ * otherwise a swap is required.
+ */
+ if (!state->blending[0].top && state->blending[1].top) {
+ blending[0] = foreground;
+ blending[1] = background[1];
+ } else {
+ blending[0] = background[0];
+ blending[1] = foreground;
+ }
+
+ tegra_plane_writel(plane, blending[0], DC_WIN_BLEND_2WIN_X);
+ tegra_plane_writel(plane, blending[1], DC_WIN_BLEND_2WIN_Y);
tegra_plane_writel(plane, background[2], DC_WIN_BLEND_3WIN_XY);
break;

@@ -495,14 +569,14 @@ static int tegra_plane_atomic_check(struct drm_plane *plane,
struct tegra_bo_tiling *tiling = &plane_state->tiling;
struct tegra_plane *tegra = to_tegra_plane(plane);
struct tegra_dc *dc = to_tegra_dc(state->crtc);
- unsigned int format;
int err;

/* no need for further checks if the plane is being disabled */
if (!state->crtc)
return 0;

- err = tegra_plane_format(state->fb->format->format, &format,
+ err = tegra_plane_format(state->fb->format->format,
+ &plane_state->format,
&plane_state->swap);
if (err < 0)
return err;
@@ -514,21 +588,11 @@ static int tegra_plane_atomic_check(struct drm_plane *plane,
* be emulated by disabling alpha blending for the plane.
*/
if (!dc->soc->supports_blending) {
- if (!tegra_plane_format_has_alpha(format)) {
- err = tegra_plane_format_get_alpha(format, &format);
- if (err < 0)
- return err;
-
- plane_state->opaque = true;
- } else {
- plane_state->opaque = false;
- }
-
- tegra_plane_check_dependent(tegra, plane_state);
+ err = tegra_plane_setup_legacy_state(tegra, plane_state);
+ if (err < 0)
+ return err;
}

- plane_state->format = format;
-
err = tegra_fb_get_tiling(state->fb, tiling);
if (err < 0)
return err;
@@ -680,9 +744,7 @@ static struct drm_plane *tegra_primary_plane_create(struct drm_device *drm,
}

drm_plane_helper_add(&plane->base, &tegra_plane_helper_funcs);
-
- if (dc->soc->supports_blending)
- drm_plane_create_zpos_property(&plane->base, 0, 0, 255);
+ drm_plane_create_zpos_property(&plane->base, plane->index, 0, 255);

return &plane->base;
}
@@ -959,9 +1021,7 @@ static struct drm_plane *tegra_dc_overlay_plane_create(struct drm_device *drm,
}

drm_plane_helper_add(&plane->base, &tegra_plane_helper_funcs);
-
- if (dc->soc->supports_blending)
- drm_plane_create_zpos_property(&plane->base, 0, 0, 255);
+ drm_plane_create_zpos_property(&plane->base, plane->index, 0, 255);

return &plane->base;
}
diff --git a/drivers/gpu/drm/tegra/plane.c b/drivers/gpu/drm/tegra/plane.c
index 176ef46c615c..0406c2ef432c 100644
--- a/drivers/gpu/drm/tegra/plane.c
+++ b/drivers/gpu/drm/tegra/plane.c
@@ -23,6 +23,7 @@ static void tegra_plane_destroy(struct drm_plane *plane)

static void tegra_plane_reset(struct drm_plane *plane)
{
+ struct tegra_plane *p = to_tegra_plane(plane);
struct tegra_plane_state *state;

if (plane->state)
@@ -35,6 +36,8 @@ static void tegra_plane_reset(struct drm_plane *plane)
if (state) {
plane->state = &state->base;
plane->state->plane = plane;
+ plane->state->zpos = p->index;
+ plane->state->normalized_zpos = p->index;
}
}

@@ -55,8 +58,8 @@ tegra_plane_atomic_duplicate_state(struct drm_plane *plane)
copy->swap = state->swap;
copy->opaque = state->opaque;

- for (i = 0; i < 3; i++)
- copy->dependent[i] = state->dependent[i];
+ for (i = 0; i < 2; i++)
+ copy->blending[i] = state->blending[i];

return &copy->base;
}
@@ -267,24 +270,8 @@ static bool __drm_format_has_alpha(u32 format)
return false;
}

-/*
- * This is applicable to Tegra20 and Tegra30 only where the opaque formats can
- * be emulated using the alpha formats and alpha blending disabled.
- */
-bool tegra_plane_format_has_alpha(unsigned int format)
-{
- switch (format) {
- case WIN_COLOR_DEPTH_B5G5R5A1:
- case WIN_COLOR_DEPTH_A1B5G5R5:
- case WIN_COLOR_DEPTH_R8G8B8A8:
- case WIN_COLOR_DEPTH_B8G8R8A8:
- return true;
- }
-
- return false;
-}
-
-int tegra_plane_format_get_alpha(unsigned int opaque, unsigned int *alpha)
+static int tegra_plane_format_get_alpha(unsigned int opaque,
+ unsigned int *alpha)
{
if (tegra_plane_format_is_yuv(opaque, NULL)) {
*alpha = opaque;
@@ -316,6 +303,67 @@ int tegra_plane_format_get_alpha(unsigned int opaque, unsigned int *alpha)
return -EINVAL;
}

+/*
+ * This is applicable to Tegra20 and Tegra30 only where the opaque formats can
+ * be emulated using the alpha formats and alpha blending disabled.
+ */
+static int tegra_plane_setup_opacity(struct tegra_plane *tegra,
+ struct tegra_plane_state *state)
+{
+ unsigned int format;
+ int err;
+
+ switch (state->format) {
+ case WIN_COLOR_DEPTH_B5G5R5A1:
+ case WIN_COLOR_DEPTH_A1B5G5R5:
+ case WIN_COLOR_DEPTH_R8G8B8A8:
+ case WIN_COLOR_DEPTH_B8G8R8A8:
+ state->opaque = false;
+ break;
+
+ default:
+ err = tegra_plane_format_get_alpha(state->format, &format);
+ if (err < 0)
+ return err;
+
+ state->format = format;
+ state->opaque = true;
+ break;
+ }
+
+ return 0;
+}
+
+static int tegra_plane_check_transparency(struct tegra_plane *tegra,
+ struct tegra_plane_state *state)
+{
+ struct drm_plane_state *old, *plane_state;
+ struct drm_plane *plane;
+
+ old = drm_atomic_get_old_plane_state(state->base.state, &tegra->base);
+
+ /* check if zpos / transparency changed */
+ if (old->normalized_zpos == state->base.normalized_zpos &&
+ to_tegra_plane_state(old)->opaque == state->opaque)
+ return 0;
+
+ /* include all sibling planes into this commit */
+ drm_for_each_plane(plane, tegra->base.dev) {
+ struct tegra_plane *p = to_tegra_plane(plane);
+
+ /* skip this plane and planes on different CRTCs */
+ if (p == tegra || p->dc != tegra->dc)
+ continue;
+
+ plane_state = drm_atomic_get_plane_state(state->base.state,
+ plane);
+ if (IS_ERR(plane_state))
+ return PTR_ERR(plane_state);
+ }
+
+ return 1;
+}
+
static unsigned int tegra_plane_get_overlap_index(struct tegra_plane *plane,
struct tegra_plane *other)
{
@@ -336,61 +384,98 @@ static unsigned int tegra_plane_get_overlap_index(struct tegra_plane *plane,
return index;
}

-void tegra_plane_check_dependent(struct tegra_plane *tegra,
- struct tegra_plane_state *state)
+static void tegra_plane_update_transparency(struct tegra_plane *tegra,
+ struct tegra_plane_state *state)
{
- struct drm_plane_state *old, *new;
+ struct drm_plane_state *new;
struct drm_plane *plane;
- unsigned int zpos[2];
unsigned int i;

- for (i = 0; i < 2; i++)
- zpos[i] = 0;
-
- for_each_oldnew_plane_in_state(state->base.state, plane, old, new, i) {
+ for_each_new_plane_in_state(state->base.state, plane, new, i) {
struct tegra_plane *p = to_tegra_plane(plane);
unsigned index;

/* skip this plane and planes on different CRTCs */
- if (p == tegra || new->crtc != state->base.crtc)
+ if (p == tegra || p->dc != tegra->dc)
continue;

index = tegra_plane_get_overlap_index(tegra, p);

- state->dependent[index] = false;
+ if (new->fb && __drm_format_has_alpha(new->fb->format->format))
+ state->blending[index].alpha = true;
+ else
+ state->blending[index].alpha = false;
+
+ if (new->normalized_zpos > state->base.normalized_zpos)
+ state->blending[index].top = true;
+ else
+ state->blending[index].top = false;

/*
- * If any of the other planes is on top of this plane and uses
- * a format with an alpha component, mark this plane as being
- * dependent, meaning it's alpha value will be 1 minus the sum
- * of alpha components of the overlapping planes.
+ * Missing framebuffer means that plane is disabled, in this
+ * case mark B / C window as top to be able to differentiate
+ * windows indices order in regards to zPos for the middle
+ * window X / Y registers programming.
*/
- if (p->index > tegra->index) {
- if (__drm_format_has_alpha(new->fb->format->format))
- state->dependent[index] = true;
-
- /* keep track of the Z position */
- zpos[index] = p->index;
- }
+ if (!new->fb)
+ state->blending[index].top = (index == 1);
}
+}
+
+static int tegra_plane_setup_transparency(struct tegra_plane *tegra,
+ struct tegra_plane_state *state)
+{
+ struct tegra_plane_state *tegra_state;
+ struct drm_plane_state *new;
+ struct drm_plane *plane;
+ int err;

/*
- * The region where three windows overlap is the intersection of the
- * two regions where two windows overlap. It contributes to the area
- * if any of the windows on top of it have an alpha component.
+ * If planes zpos / transparency changed, sibling planes blending
+ * state may require adjustment and in this case they will be included
+ * into this atom commit, otherwise blending state is unchanged.
*/
- for (i = 0; i < 2; i++)
- state->dependent[2] = state->dependent[2] ||
- state->dependent[i];
+ err = tegra_plane_check_transparency(tegra, state);
+ if (err <= 0)
+ return err;

/*
- * However, if any of the windows on top of this window is opaque, it
- * will completely conceal this window within that area, so avoid the
- * window from contributing to the area.
+ * All planes are now in the atomic state, walk them up and update
+ * transparency state for each plane.
*/
- for (i = 0; i < 2; i++) {
- if (zpos[i] > tegra->index)
- state->dependent[2] = state->dependent[2] &&
- state->dependent[i];
+ drm_for_each_plane(plane, tegra->base.dev) {
+ struct tegra_plane *p = to_tegra_plane(plane);
+
+ /* skip planes on different CRTCs */
+ if (p->dc != tegra->dc)
+ continue;
+
+ new = drm_atomic_get_new_plane_state(state->base.state, plane);
+ tegra_state = to_tegra_plane_state(new);
+
+ /*
+ * There is no need to update blending state for the disabled
+ * plane.
+ */
+ if (new->fb)
+ tegra_plane_update_transparency(p, tegra_state);
}
+
+ return 0;
+}
+
+int tegra_plane_setup_legacy_state(struct tegra_plane *tegra,
+ struct tegra_plane_state *state)
+{
+ int err;
+
+ err = tegra_plane_setup_opacity(tegra, state);
+ if (err < 0)
+ return err;
+
+ err = tegra_plane_setup_transparency(tegra, state);
+ if (err < 0)
+ return err;
+
+ return 0;
}
diff --git a/drivers/gpu/drm/tegra/plane.h b/drivers/gpu/drm/tegra/plane.h
index 6938719e7e5d..7360ddfafee8 100644
--- a/drivers/gpu/drm/tegra/plane.h
+++ b/drivers/gpu/drm/tegra/plane.h
@@ -34,6 +34,11 @@ static inline struct tegra_plane *to_tegra_plane(struct drm_plane *plane)
return container_of(plane, struct tegra_plane, base);
}

+struct tegra_plane_legacy_blending_state {
+ bool alpha;
+ bool top;
+};
+
struct tegra_plane_state {
struct drm_plane_state base;

@@ -42,8 +47,8 @@ struct tegra_plane_state {
u32 swap;

/* used for legacy blending support only */
+ struct tegra_plane_legacy_blending_state blending[2];
bool opaque;
- bool dependent[3];
};

static inline struct tegra_plane_state *
@@ -62,9 +67,7 @@ int tegra_plane_state_add(struct tegra_plane *plane,

int tegra_plane_format(u32 fourcc, u32 *format, u32 *swap);
bool tegra_plane_format_is_yuv(unsigned int format, bool *planar);
-bool tegra_plane_format_has_alpha(unsigned int format);
-int tegra_plane_format_get_alpha(unsigned int opaque, unsigned int *alpha);
-void tegra_plane_check_dependent(struct tegra_plane *tegra,
- struct tegra_plane_state *state);
+int tegra_plane_setup_legacy_state(struct tegra_plane *tegra,
+ struct tegra_plane_state *state);

#endif /* TEGRA_PLANE_H */
--
2.17.0