Re: [PATCH v3] drm/sun4i: de2: Reimplement plane z position setting logic

From: Maxime Ripard
Date: Wed Jan 13 2021 - 04:14:46 EST

Hi,

On Wed, Jan 06, 2021 at 09:46:30PM +0100, Jernej Skrabec wrote:
> From: Roman Stratiienko <roman.stratiienko@xxxxxxxxxxxxxxx>
>
> To set blending channel order register software needs to know state and
> position of each channel, which impossible at plane commit stage.
>
> Move this procedure to atomic_flush stage, where all necessary information
> is available.

Expanding a bit on what the blending order register is supposed to be
doing, why it's impossible at the plane commit, and why atomic_flush is
a better option would be nice

> Fixes: f88c5ee77496 ("drm/sun4i: Implement zpos for DE2")
> Fixes: d8b3f454dab4 ("drm/sun4i: sun8i: Avoid clearing blending order at each atomic commit")
> Signed-off-by: Roman Stratiienko <roman.stratiienko@xxxxxxxxxxxxxxx>
> [rebased, addressed comments]
> Signed-off-by: Jernej Skrabec <jernej.skrabec@xxxxxxxx>
> ---
> drivers/gpu/drm/sun4i/sun8i_mixer.c | 57 +++++++++++++++++++++-----
> drivers/gpu/drm/sun4i/sun8i_mixer.h | 5 +++
> drivers/gpu/drm/sun4i/sun8i_ui_layer.c | 42 +++----------------
> drivers/gpu/drm/sun4i/sun8i_vi_layer.c | 42 +++----------------
> 4 files changed, 64 insertions(+), 82 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.c b/drivers/gpu/drm/sun4i/sun8i_mixer.c
> index 5b42cf25cc86..d2153b10b08d 100644
> --- a/drivers/gpu/drm/sun4i/sun8i_mixer.c
> +++ b/drivers/gpu/drm/sun4i/sun8i_mixer.c
> @@ -250,6 +250,50 @@ int sun8i_mixer_drm_format_to_hw(u32 format, u32 *hw_format)
>
> static void sun8i_mixer_commit(struct sunxi_engine *engine)
> {
> + struct sun8i_mixer *mixer = engine_to_sun8i_mixer(engine);
> + int channel_by_zpos[SUN8I_MIXER_MAX_CHANNELS];
> + u32 base = sun8i_blender_base(mixer);
> + u32 route = 0, pipe_ctl = 0;
> + unsigned int channel_count;
> + int i, j;
> +
> + channel_count = mixer->cfg->vi_num + mixer->cfg->ui_num;
> +
> + DRM_DEBUG_DRIVER("Update blender routing\n");
> +
> + for (i = 0; i < SUN8I_MIXER_MAX_CHANNELS; i++)
> + channel_by_zpos[i] = -1;
> +
> + for (i = 0; i < channel_count; i++) {
> + int zpos = mixer->channel_zpos[i];

Why do we need the channel_zpos in the mixer structure, this looks
related to the state itself, so we should store it into a custom state
structure

> + if (zpos >= 0 && zpos < channel_count)
> + channel_by_zpos[zpos] = i;
> + }
> +
> + j = 0;
> + for (i = 0; i < channel_count; i++) {
> + int ch = channel_by_zpos[i];
> +
> + if (ch >= 0) {
> + pipe_ctl |= SUN8I_MIXER_BLEND_PIPE_CTL_EN(j);
> + route |= ch << SUN8I_MIXER_BLEND_ROUTE_PIPE_SHIFT(j);
> + j++;
> + }
> + }

Similarly, having a comment somewhere to explain that algorithm would be
nice.

> + /*
> + * Set fill color of bottom plane to black. Generally not needed
> + * except when VI plane is at bottom (zpos = 0) and enabled.
> + */
> + pipe_ctl |= SUN8I_MIXER_BLEND_PIPE_CTL_FC_EN(0);
> +
> + regmap_write(mixer->engine.regs,
> + SUN8I_MIXER_BLEND_PIPE_CTL(base), pipe_ctl);
> +
> + regmap_write(mixer->engine.regs,
> + SUN8I_MIXER_BLEND_ROUTE(base), route);
> +
> DRM_DEBUG_DRIVER("Committing changes\n");
>
> regmap_write(engine->regs, SUN8I_MIXER_GLOBAL_DBUFF,
> @@ -479,23 +523,16 @@ static int sun8i_mixer_bind(struct device *dev, struct device *master,
> regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_BKCOLOR(base),
> SUN8I_MIXER_BLEND_COLOR_BLACK);
>
> - /*
> - * Set fill color of bottom plane to black. Generally not needed
> - * except when VI plane is at bottom (zpos = 0) and enabled.
> - */
> - regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_PIPE_CTL(base),
> - SUN8I_MIXER_BLEND_PIPE_CTL_FC_EN(0));
> regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_ATTR_FCOLOR(base, 0),
> SUN8I_MIXER_BLEND_COLOR_BLACK);
>
> plane_cnt = mixer->cfg->vi_num + mixer->cfg->ui_num;
> - for (i = 0; i < plane_cnt; i++)
> + for (i = 0; i < plane_cnt; i++) {
> + mixer->channel_zpos[i] = -1;
> regmap_write(mixer->engine.regs,
> SUN8I_MIXER_BLEND_MODE(base, i),
> SUN8I_MIXER_BLEND_MODE_DEF);
> -
> - regmap_update_bits(mixer->engine.regs, SUN8I_MIXER_BLEND_PIPE_CTL(base),
> - SUN8I_MIXER_BLEND_PIPE_CTL_EN_MSK, 0);
> + }
>
> return 0;
>
> diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.h b/drivers/gpu/drm/sun4i/sun8i_mixer.h
> index 7576b523fdbb..7b378d6e4dd9 100644
> --- a/drivers/gpu/drm/sun4i/sun8i_mixer.h
> +++ b/drivers/gpu/drm/sun4i/sun8i_mixer.h
> @@ -12,6 +12,8 @@
>
> #include "sunxi_engine.h"
>
> +#define SUN8I_MIXER_MAX_CHANNELS 5
> +
> #define SUN8I_MIXER_SIZE(w, h) (((h) - 1) << 16 | ((w) - 1))
> #define SUN8I_MIXER_COORD(x, y) ((y) << 16 | (x))
>
> @@ -179,6 +181,9 @@ struct sun8i_mixer {
>
> struct clk *bus_clk;
> struct clk *mod_clk;
> +
> + /* -1 means that layer is disabled */
> + int channel_zpos[SUN8I_MIXER_MAX_CHANNELS];
> };
>
> static inline struct sun8i_mixer *
> diff --git a/drivers/gpu/drm/sun4i/sun8i_ui_layer.c b/drivers/gpu/drm/sun4i/sun8i_ui_layer.c
> index 816ad4ce8996..9f82e7c33e90 100644
> --- a/drivers/gpu/drm/sun4i/sun8i_ui_layer.c
> +++ b/drivers/gpu/drm/sun4i/sun8i_ui_layer.c
> @@ -24,12 +24,10 @@
> #include "sun8i_ui_scaler.h"
>
> static void sun8i_ui_layer_enable(struct sun8i_mixer *mixer, int channel,
> - int overlay, bool enable, unsigned int zpos,
> - unsigned int old_zpos)
> + int overlay, bool enable, unsigned int zpos)
> {
> - u32 val, bld_base, ch_base;
> + u32 val, ch_base;
>
> - bld_base = sun8i_blender_base(mixer);
> ch_base = sun8i_channel_base(mixer, channel);
>
> DRM_DEBUG_DRIVER("%sabling channel %d overlay %d\n",
> @@ -44,32 +42,7 @@ static void sun8i_ui_layer_enable(struct sun8i_mixer *mixer, int channel,
> SUN8I_MIXER_CHAN_UI_LAYER_ATTR(ch_base, overlay),
> SUN8I_MIXER_CHAN_UI_LAYER_ATTR_EN, val);
>
> - if (!enable || zpos != old_zpos) {
> - regmap_update_bits(mixer->engine.regs,
> - SUN8I_MIXER_BLEND_PIPE_CTL(bld_base),
> - SUN8I_MIXER_BLEND_PIPE_CTL_EN(old_zpos),
> - 0);
> -
> - regmap_update_bits(mixer->engine.regs,
> - SUN8I_MIXER_BLEND_ROUTE(bld_base),
> - SUN8I_MIXER_BLEND_ROUTE_PIPE_MSK(old_zpos),
> - 0);
> - }
> -
> - if (enable) {
> - val = SUN8I_MIXER_BLEND_PIPE_CTL_EN(zpos);
> -
> - regmap_update_bits(mixer->engine.regs,
> - SUN8I_MIXER_BLEND_PIPE_CTL(bld_base),
> - val, val);
> -
> - val = channel << SUN8I_MIXER_BLEND_ROUTE_PIPE_SHIFT(zpos);
> -
> - regmap_update_bits(mixer->engine.regs,
> - SUN8I_MIXER_BLEND_ROUTE(bld_base),
> - SUN8I_MIXER_BLEND_ROUTE_PIPE_MSK(zpos),
> - val);
> - }
> + mixer->channel_zpos[channel] = enable ? zpos : -1;
> }
>
> static int sun8i_ui_layer_update_coord(struct sun8i_mixer *mixer, int channel,
> @@ -267,11 +240,9 @@ static void sun8i_ui_layer_atomic_disable(struct drm_plane *plane,
> struct drm_plane_state *old_state)
> {
> struct sun8i_ui_layer *layer = plane_to_sun8i_ui_layer(plane);
> - unsigned int old_zpos = old_state->normalized_zpos;
> struct sun8i_mixer *mixer = layer->mixer;
>
> - sun8i_ui_layer_enable(mixer, layer->channel, layer->overlay, false, 0,
> - old_zpos);
> + sun8i_ui_layer_enable(mixer, layer->channel, layer->overlay, false, 0);
> }
>
> static void sun8i_ui_layer_atomic_update(struct drm_plane *plane,
> @@ -279,12 +250,11 @@ static void sun8i_ui_layer_atomic_update(struct drm_plane *plane,
> {
> struct sun8i_ui_layer *layer = plane_to_sun8i_ui_layer(plane);
> unsigned int zpos = plane->state->normalized_zpos;
> - unsigned int old_zpos = old_state->normalized_zpos;
> struct sun8i_mixer *mixer = layer->mixer;
>
> if (!plane->state->visible) {
> sun8i_ui_layer_enable(mixer, layer->channel,
> - layer->overlay, false, 0, old_zpos);
> + layer->overlay, false, 0);
> return;
> }
>
> @@ -295,7 +265,7 @@ static void sun8i_ui_layer_atomic_update(struct drm_plane *plane,
> sun8i_ui_layer_update_buffer(mixer, layer->channel,
> layer->overlay, plane);
> sun8i_ui_layer_enable(mixer, layer->channel, layer->overlay,
> - true, zpos, old_zpos);
> + true, zpos);
> }

The prototype change could be in a separate patch, it would make things
easier to review.

Maxime

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