Re: [RFC 3/4] drm/sun4i: Reimplement plane z position setting logic
From: Jernej Åkrabec
Date: Sun Dec 29 2019 - 08:34:26 EST
Dne nedelja, 29. december 2019 ob 14:13:06 CET je Roman Stratiienko
napisal(a):
> My proposal is to go with DRM_DEBUG_DRIVER for now.
> In case stable branches would be interested in these fixes, it will be
> easier to backport.
Fair enough, but you need to add at least Fixes tag.
Best regards,
Jernej
>
> Also I am using v5.4 for testing since Google AOSP patches does not
> work correctly with mainline and missing for kernel-next.
> Maintaining 2 variants will be much harder for me.
>
> On Sun, Dec 29, 2019 at 3:02 PM Jernej Åkrabec <jernej.skrabec@xxxxxxxx>
wrote:
> > Dne nedelja, 29. december 2019 ob 13:47:38 CET je Roman Stratiienko
> >
> > napisal(a):
> > > On Sun, Dec 29, 2019 at 2:18 PM Jernej Åkrabec <jernej.skrabec@xxxxxxxx>
> >
> > wrote:
> > > > Dne nedelja, 29. december 2019 ob 13:08:19 CET je Roman Stratiienko
> > > >
> > > > napisal(a):
> > > > > Hello Jernej,
> > > > >
> > > > > Thank you for review.
> > > > >
> > > > > On Sun, Dec 29, 2019 at 11:40 AM Jernej Åkrabec
> > > > > <jernej.skrabec@xxxxxxxx>
> > > >
> > > > wrote:
> > > > > > Hi!
> > > > > >
> > > > > > Dne sobota, 28. december 2019 ob 21:28:17 CET je
> > > > > >
> > > > > > roman.stratiienko@xxxxxxxxxxxxxxx napisal(a):
> > > > > > > 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.
> > > > > > >
> > > > > > > Signed-off-by: Roman Stratiienko
> > > > > > > <roman.stratiienko@xxxxxxxxxxxxxxx>
> > > > > > > ---
> > > > > > >
> > > > > > > drivers/gpu/drm/sun4i/sun8i_mixer.c | 47
> > > > > > > +++++++++++++++++++++++++-
> > > > > > > drivers/gpu/drm/sun4i/sun8i_mixer.h | 3 ++
> > > > > > > drivers/gpu/drm/sun4i/sun8i_ui_layer.c | 42
> > > > > > > ++++-------------------
> > > > > > > drivers/gpu/drm/sun4i/sun8i_vi_layer.c | 39
> > > > > > > +++------------------
> > > > > > > 4 files changed, 60 insertions(+), 71 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.c
> > > > > > > b/drivers/gpu/drm/sun4i/sun8i_mixer.c index
> > > > > > > bb9a665fd053..da84fccf7784
> > > > > > > 100644
> > > > > > > --- a/drivers/gpu/drm/sun4i/sun8i_mixer.c
> > > > > > > +++ b/drivers/gpu/drm/sun4i/sun8i_mixer.c
> > > > > > > @@ -307,8 +307,47 @@ static void sun8i_atomic_begin(struct
> > > > > > > sunxi_engine
> > > > > > > *engine,
> > > > > > >
> > > > > > > static void sun8i_mixer_commit(struct sunxi_engine *engine)
> > > > > > > {
> > > > > > >
> > > > > > > - DRM_DEBUG_DRIVER("Committing changes\n");
> > > > > > > + struct sun8i_mixer *mixer = engine_to_sun8i_mixer(engine);
> > > > > > > + u32 base = sun8i_blender_base(mixer);
> > > > > > > + int i, j;
> > > > > > > + int channel_by_zpos[4] = {-1, -1, -1, -1};
> > > > > > > + u32 route = 0, pipe_ctl = 0;
> > > > > > > +
> > > > > > > + DRM_DEBUG_DRIVER("Update blender routing\n");
> > > > > >
> > > > > > Use drm_dbg().
> > > > > >
> > > > > > > + for (i = 0; i < 4; i++) {
> > > > > > > + int zpos = mixer->channel_zpos[i];
> > > > > >
> > > > > > channel_zpos can hold 5 elements which is also theoretical maximum
> > > > > > for
> > > > > > current HW design. Why do you check only 4 elements?
> > > > >
> > > > > I'll use plane_cnt as it done in mixer_bind
> > > > >
> > > > > > It would be great to introduce a macro like SUN8I_MIXER_MAX_LAYERS
> > > > > > so
> > > > > > everyone would understand where this number comes from.
> > > > >
> > > > > Will do.
> > > > >
> > > > > > > +
> > > > > > > + if (zpos >= 0 && zpos < 4)
> > > > > > > + channel_by_zpos[zpos] = i;
> > > > > > > + }
> > > > > > > +
> > > > > > > + j = 0;
> > > > > > > + for (i = 0; i < 4; 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++;
> > > > > > > + }
> > > > > > > + }
> > > > > > > +
> > > > > > > + for (i = 0; i < 4 && j < 4; i++) {
> > > > > > > + int zpos = mixer->channel_zpos[i];
> > > > > > >
> > > > > > > + if (zpos < 0) {
> > > > > > > + route |= i <<
> > > > > >
> > > > > > SUN8I_MIXER_BLEND_ROUTE_PIPE_SHIFT(j);
> > > > > >
> > > > > > > + j++;
> > > > > > > + }
> > > > > > > + }
> > > > > > > +
> > > > > > > + regmap_update_bits(mixer->engine.regs,
> > > > > >
> > > > > > SUN8I_MIXER_BLEND_PIPE_CTL(base),
> > > > > >
> > > > > > > + SUN8I_MIXER_BLEND_PIPE_CTL_EN_MSK,
> > > > > >
> > > > > > pipe_ctl);
> > > > > >
> > > > > > > +
> > > > > > > + regmap_write(mixer->engine.regs,
> > > > > > > + SUN8I_MIXER_BLEND_ROUTE(base), route);
> > > > > > > +
> > > > > > > + DRM_DEBUG_DRIVER("Committing changes\n");
> > > > > >
> > > > > > Use drm_dbg().
> > > > >
> > > > > According to
> > > > > https://github.com/torvalds/linux/commit/99a954874e7b9f0c80584765755
> > > > > 93b3
> > > > > beb
> > > > > 5731a5#diff-b0cd2d683c6afbab7bd54173cfd3d3ecR289 ,
> > > > > DRM_DEBUG_DRIVER uses drm_dbg.
> > > > > Also, using drm_dbg with category macro would require larger indent,
> > > > > making harder to fit in 80 chars limit.
> > > >
> > > > From what I can see, category is already defined by macro name. Check
> > > > here:
> > > > https://cgit.freedesktop.org/drm/drm-misc/tree/include/drm/drm_print.h
> > > > #n46
> > > > 5
> > > >
> > > > So it should be actually shorter.
> > >
> > > Ah, it something very recent.
> > > drm_dbg also require drm_device struct
> > > Do you know the best way to extract it from `struct engine`?
> >
> > I don't think there is a way. I guess we can solve this later. Maxime, any
> > thoughts?
> >
> > Best regards,
> > Jernej
> >
> > > > > Are there any plans to deprecate DRM_DEBUG_DRIVER macro?
> > > >
> > > > Yes, at least I understand following commit message in such manner:
> > > > https://cgit.freedesktop.org/drm/drm-misc/commit/?
> > > > id=93ccfa9a4eca482216c5caf88be77e5ffa0d744a
> > > >
> > > > Best regards,
> > > > Jernej
> > > >
> > > > > > > regmap_write(engine->regs, SUN8I_MIXER_GLOBAL_DBUFF,
> > > > > > >
> > > > > > > SUN8I_MIXER_GLOBAL_DBUFF_ENABLE);
> > > > > > >
> > > > > > > }
> > > > > > >
> > > > > > > @@ -422,6 +461,12 @@ static int sun8i_mixer_bind(struct device
> > > > > > > *dev,
> > > > > > > struct
> > > > > > > device *master, mixer->engine.ops = &sun8i_engine_ops;
> > > > > > >
> > > > > > > mixer->engine.node = dev->of_node;
> > > > > > >
> > > > > > > + mixer->channel_zpos[0] = -1;
> > > > > > > + mixer->channel_zpos[1] = -1;
> > > > > > > + mixer->channel_zpos[2] = -1;
> > > > > > > + mixer->channel_zpos[3] = -1;
> > > > > > > + mixer->channel_zpos[4] = -1;
> > > > > > > +
> > > > > >
> > > > > > for loop would be better, especially using proposed macro.
> > > > >
> > > > > I'll put it into already existent for-loop below.
> > > > >
> > > > > > Best regards,
> > > > > > Jernej
> > > > > >
> > > > > > > /*
> > > > > > >
> > > > > > > * While this function can fail, we shouldn't do anything
> > > > > > > * if this happens. Some early DE2 DT entries don't
> > > > > > > provide
> > > > > > >
> > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.h
> > > > > > > b/drivers/gpu/drm/sun4i/sun8i_mixer.h index
> > > > > > > 915479cc3077..9c2ff87923d8
> > > > > > > 100644
> > > > > > > --- a/drivers/gpu/drm/sun4i/sun8i_mixer.h
> > > > > > > +++ b/drivers/gpu/drm/sun4i/sun8i_mixer.h
> > > > > > > @@ -178,6 +178,9 @@ struct sun8i_mixer {
> > > > > > >
> > > > > > > struct clk *bus_clk;
> > > > > > > struct clk *mod_clk;
> > > > > > >
> > > > > > > +
> > > > > > > + /* -1 means that layer is disabled */
> > > > > > > + int channel_zpos[5];
> > > > > > >
> > > > > > > };
> > > > > > >
> > > > > > > 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
> > > > > > > 893076716070..23c2f4b68c89
> > > > > > > 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, @@ -235,11 +208,9 @@ 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,
> > > > > > >
> > > > > > > @@ -247,12 +218,11 @@ 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;
> > > > > > >
> > > > > > > }
> > > > > > >
> > > > > > > @@ -263,7 +233,7 @@ 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);
> > > > > > >
> > > > > > > }
> > > > > > >
> > > > > > > static struct drm_plane_helper_funcs
> > > > > > > sun8i_ui_layer_helper_funcs =
> > > > > > > {
> > > > > > >
> > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun8i_vi_layer.c
> > > > > > > b/drivers/gpu/drm/sun4i/sun8i_vi_layer.c index
> > > > > > > 42d445d23773..97cbc98bf781
> > > > > > > 100644
> > > > > > > --- a/drivers/gpu/drm/sun4i/sun8i_vi_layer.c
> > > > > > > +++ b/drivers/gpu/drm/sun4i/sun8i_vi_layer.c
> > > > > > > @@ -17,8 +17,7 @@
> > > > > > >
> > > > > > > #include "sun8i_vi_scaler.h"
> > > > > > >
> > > > > > > static void sun8i_vi_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;
> > > > > > >
> > > > > > > @@ -37,32 +36,7 @@ static void sun8i_vi_layer_enable(struct
> > > > > > > sun8i_mixer
> > > > > > > *mixer, int channel, SUN8I_MIXER_CHAN_VI_LAYER_ATTR(ch_base,
> > > > > > > overlay),
> > > > > > >
> > > > > > > SUN8I_MIXER_CHAN_VI_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_vi_layer_update_coord(struct sun8i_mixer
> > > > > > > *mixer,
> > > > > > > int
> > > > > > >
> > > > > > > channel, @@ -350,11 +324,9 @@ static void
> > > > > > > sun8i_vi_layer_atomic_disable(struct drm_plane *plane, struct
> > > > > > > drm_plane_state *old_state)
> > > > > > >
> > > > > > > {
> > > > > > >
> > > > > > > struct sun8i_vi_layer *layer =
> > > > > > > plane_to_sun8i_vi_layer(plane);
> > > > > > >
> > > > > > > - unsigned int old_zpos = old_state->normalized_zpos;
> > > > > > >
> > > > > > > struct sun8i_mixer *mixer = layer->mixer;
> > > > > > >
> > > > > > > - sun8i_vi_layer_enable(mixer, layer->channel,
> > > > > > > layer->overlay,
> > > > > >
> > > > > > false, 0,
> > > > > >
> > > > > > > - old_zpos);
> > > > > > > + sun8i_vi_layer_enable(mixer, layer->channel,
> > > > > > > layer->overlay,
> > > > > > > false,
> > > > > >
> > > > > > 0);
> > > > > >
> > > > > > > }
> > > > > > >
> > > > > > > static void sun8i_vi_layer_atomic_update(struct drm_plane
> > > > > > > *plane,
> > > > > > >
> > > > > > > @@ -362,12 +334,11 @@ static void
> > > > > > > sun8i_vi_layer_atomic_update(struct
> > > > > > > drm_plane *plane, {
> > > > > > >
> > > > > > > struct sun8i_vi_layer *layer =
> > > > > > > plane_to_sun8i_vi_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_vi_layer_enable(mixer, layer->channel,
> > > > > > >
> > > > > > > - layer->overlay, false, 0,
> > > > > >
> > > > > > old_zpos);
> > > > > >
> > > > > > > + layer->overlay, false, 0);
> > > > > > >
> > > > > > > return;
> > > > > > >
> > > > > > > }
> > > > > > >
> > > > > > > @@ -378,7 +349,7 @@ static void
> > > > > > > sun8i_vi_layer_atomic_update(struct
> > > > > > > drm_plane *plane, sun8i_vi_layer_update_buffer(mixer,
> > > > > > > layer->channel,
> > > > > > >
> > > > > > > layer->overlay, plane);
> > > > > > >
> > > > > > > sun8i_vi_layer_enable(mixer, layer->channel,
> > > > > > > layer->overlay,
> > > > > > >
> > > > > > > - true, zpos, old_zpos);
> > > > > > > + true, zpos);
> > > > > > >
> > > > > > > }
> > > > > > >
> > > > > > > static struct drm_plane_helper_funcs
> > > > > > > sun8i_vi_layer_helper_funcs =
> > > > > > > {