Re: [PATCH v6 08/13] drm/sun4i: add support for Allwinner DE2 mixers

[Maxime Ripard]

On Thu, May 04, 2017 at 07:48:53PM +0800, Icenowy Zheng wrote:
> Allwinner have a new "Display Engine 2.0" in their new SoCs, which comes
> with mixers to do graphic processing and feed data to TCON, like the old
> backends and frontends.
> 
> Add support for the mixer on Allwinner V3s SoC; it's the simplest one.
> 
> Currently a lot of functions are still missing -- more investigations
> are needed to gain enough information for them.
> 
> Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
> ---
> Changes in v6:
> - Rebased on wens's multi-pipeline patchset.
> Changes in v5:
> - Changed some code alignment.
> - Request real 32-bit DMA (prepare for 64-bit SoCs).
> Changes in v4:
> - Killed some dead code according to Jernej.
> 
>  drivers/gpu/drm/sun4i/Kconfig       |  10 +
>  drivers/gpu/drm/sun4i/Makefile      |   3 +
>  drivers/gpu/drm/sun4i/sun8i_layer.c | 140 +++++++++++++
>  drivers/gpu/drm/sun4i/sun8i_layer.h |  36 ++++
>  drivers/gpu/drm/sun4i/sun8i_mixer.c | 394 ++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/sun4i/sun8i_mixer.h | 137 +++++++++++++
>  6 files changed, 720 insertions(+)
>  create mode 100644 drivers/gpu/drm/sun4i/sun8i_layer.c
>  create mode 100644 drivers/gpu/drm/sun4i/sun8i_layer.h
>  create mode 100644 drivers/gpu/drm/sun4i/sun8i_mixer.c
>  create mode 100644 drivers/gpu/drm/sun4i/sun8i_mixer.h
> 
> diff --git a/drivers/gpu/drm/sun4i/Kconfig b/drivers/gpu/drm/sun4i/Kconfig
> index 5a8227f37cc4..15557484520d 100644
> --- a/drivers/gpu/drm/sun4i/Kconfig
> +++ b/drivers/gpu/drm/sun4i/Kconfig
> @@ -22,3 +22,13 @@ config DRM_SUN4I_BACKEND
>  	  original Allwinner Display Engine, which has a backend to
>  	  do some alpha blending and feed graphics to TCON. If M is
>  	  selected the module will be called sun4i-backend.
> +
> +config DRM_SUN4I_SUN8I_MIXER

DRM_SUN8I_MIXER?

> +	tristate "Support for Allwinner Display Engine 2.0 Mixer"
> +	depends on DRM_SUN4I
> +	default MACH_SUN8I
> +	help
> +	  Choose this option if you have an Allwinner SoC with the
> +	  Allwinner Display Engine 2.0, which has a mixer to do some
> +	  graphics mixture and feed graphics to TCON, If M is
> +	  selected the module will be called sun8i-mixer.
> diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile
> index a08df56759e3..a876c6b3027c 100644
> --- a/drivers/gpu/drm/sun4i/Makefile
> +++ b/drivers/gpu/drm/sun4i/Makefile
> @@ -8,7 +8,10 @@ sun4i-tcon-y += sun4i_crtc.o
>  
>  sun4i-backend-y += sun4i_backend.o sun4i_layer.o
>  
> +sun8i-mixer-y += sun8i_mixer.o sun8i_layer.o
> +
>  obj-$(CONFIG_DRM_SUN4I)		+= sun4i-drm.o sun4i-tcon.o
>  obj-$(CONFIG_DRM_SUN4I_BACKEND)		+= sun4i-backend.o
> +obj-$(CONFIG_DRM_SUN4I_SUN8I_MIXER)	+= sun8i-mixer.o
>  obj-$(CONFIG_DRM_SUN4I)		+= sun6i_drc.o
>  obj-$(CONFIG_DRM_SUN4I)		+= sun4i_tv.o
> diff --git a/drivers/gpu/drm/sun4i/sun8i_layer.c b/drivers/gpu/drm/sun4i/sun8i_layer.c
> new file mode 100644
> index 000000000000..48f33d8e013b
> --- /dev/null
> +++ b/drivers/gpu/drm/sun4i/sun8i_layer.c
> @@ -0,0 +1,140 @@
> +/*
> + * Copyright (C) Icenowy Zheng <icenowy@xxxxxxx>
> + *
> + * Based on sun4i_layer.h, which is:
> + *   Copyright (C) 2015 Free Electrons
> + *   Copyright (C) 2015 NextThing Co
> + *
> + *   Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_plane_helper.h>
> +#include <drm/drmP.h>
> +
> +#include "sun8i_layer.h"
> +#include "sun8i_mixer.h"
> +
> +struct sun8i_plane_desc {
> +	       enum drm_plane_type     type;
> +	       const uint32_t          *formats;
> +	       uint32_t                nformats;
> +};
> +
> +static int sun8i_mixer_layer_atomic_check(struct drm_plane *plane,
> +					    struct drm_plane_state *state)
> +{
> +	return 0;
> +}

This isn't needed.

> +static void sun8i_mixer_layer_atomic_disable(struct drm_plane *plane,
> +					       struct drm_plane_state *old_state)
> +{
> +	struct sun8i_layer *layer = plane_to_sun8i_layer(plane);
> +	struct sun8i_mixer *mixer = layer->mixer;
> +
> +	sun8i_mixer_layer_enable(mixer, layer->id, false);
> +}
> +
> +static void sun8i_mixer_layer_atomic_update(struct drm_plane *plane,
> +					      struct drm_plane_state *old_state)
> +{
> +	struct sun8i_layer *layer = plane_to_sun8i_layer(plane);
> +	struct sun8i_mixer *mixer = layer->mixer;
> +
> +	sun8i_mixer_update_layer_coord(mixer, layer->id, plane);
> +	sun8i_mixer_update_layer_formats(mixer, layer->id, plane);
> +	sun8i_mixer_update_layer_buffer(mixer, layer->id, plane);
> +	sun8i_mixer_layer_enable(mixer, layer->id, true);
> +}
> +
> +static struct drm_plane_helper_funcs sun8i_mixer_layer_helper_funcs = {
> +	.atomic_check	= sun8i_mixer_layer_atomic_check,
> +	.atomic_disable	= sun8i_mixer_layer_atomic_disable,
> +	.atomic_update	= sun8i_mixer_layer_atomic_update,
> +};
> +
> +static const struct drm_plane_funcs sun8i_mixer_layer_funcs = {
> +	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
> +	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
> +	.destroy		= drm_plane_cleanup,
> +	.disable_plane		= drm_atomic_helper_disable_plane,
> +	.reset			= drm_atomic_helper_plane_reset,
> +	.update_plane		= drm_atomic_helper_update_plane,
> +};
> +
> +static const uint32_t sun8i_mixer_layer_formats[] = {
> +	DRM_FORMAT_RGB888,
> +	DRM_FORMAT_XRGB8888,
> +};
> +
> +static const struct sun8i_plane_desc sun8i_mixer_planes[] = {
> +	{
> +		.type = DRM_PLANE_TYPE_PRIMARY,
> +		.formats = sun8i_mixer_layer_formats,
> +		.nformats = ARRAY_SIZE(sun8i_mixer_layer_formats),
> +	},
> +};
> +
> +static struct sun8i_layer *sun8i_layer_init_one(struct drm_device *drm,
> +						struct sun8i_mixer *mixer,
> +						const struct sun8i_plane_desc *plane)
> +{
> +	struct sun8i_layer *layer;
> +	int ret;
> +
> +	layer = devm_kzalloc(drm->dev, sizeof(*layer), GFP_KERNEL);
> +	if (!layer)
> +		return ERR_PTR(-ENOMEM);
> +
> +	/* possible crtcs are set later */
> +	ret = drm_universal_plane_init(drm, &layer->plane, 0,
> +				       &sun8i_mixer_layer_funcs,
> +				       plane->formats, plane->nformats,
> +				       plane->type, NULL);
> +	if (ret) {
> +		dev_err(drm->dev, "Couldn't initialize layer\n");
> +		return ERR_PTR(ret);
> +	}
> +
> +	drm_plane_helper_add(&layer->plane,
> +			     &sun8i_mixer_layer_helper_funcs);
> +	layer->mixer = mixer;
> +
> +	return layer;
> +}
> +
> +struct drm_plane **sun8i_layers_init(struct drm_device *drm,
> +				     struct sunxi_engine *engine)
> +{
> +	struct drm_plane **planes;
> +	struct sun8i_mixer *mixer = engine_to_sun8i_mixer(engine);
> +	int i;
> +
> +	planes = devm_kcalloc(drm->dev, ARRAY_SIZE(sun8i_mixer_planes) + 1,
> +			      sizeof(*planes), GFP_KERNEL);
> +	if (!planes)
> +		return ERR_PTR(-ENOMEM);
> +
> +	for (i = 0; i < ARRAY_SIZE(sun8i_mixer_planes); i++) {
> +		const struct sun8i_plane_desc *plane = &sun8i_mixer_planes[i];
> +		struct sun8i_layer *layer;
> +
> +		layer = sun8i_layer_init_one(drm, mixer, plane);
> +		if (IS_ERR(layer)) {
> +			dev_err(drm->dev, "Couldn't initialize %s plane\n",
> +				i ? "overlay" : "primary");
> +			return ERR_CAST(layer);
> +		};
> +
> +		layer->id = i;
> +		planes[i] = &layer->plane;
> +	};
> +
> +	return planes;
> +}
> diff --git a/drivers/gpu/drm/sun4i/sun8i_layer.h b/drivers/gpu/drm/sun4i/sun8i_layer.h
> new file mode 100644
> index 000000000000..e5eccd27cff0
> --- /dev/null
> +++ b/drivers/gpu/drm/sun4i/sun8i_layer.h
> @@ -0,0 +1,36 @@
> +/*
> + * Copyright (C) Icenowy Zheng <icenowy@xxxxxxx>
> + *
> + * Based on sun4i_layer.h, which is:
> + *   Copyright (C) 2015 Free Electrons
> + *   Copyright (C) 2015 NextThing Co
> + *
> + *   Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#ifndef _SUN8I_LAYER_H_
> +#define _SUN8I_LAYER_H_
> +
> +struct sunxi_engine;
> +
> +struct sun8i_layer {
> +	struct drm_plane	plane;
> +	struct sun4i_drv	*drv;
> +	struct sun8i_mixer	*mixer;
> +	int			id;
> +};
> +
> +static inline struct sun8i_layer *
> +plane_to_sun8i_layer(struct drm_plane *plane)
> +{
> +	return container_of(plane, struct sun8i_layer, plane);
> +}
> +
> +struct drm_plane **sun8i_layers_init(struct drm_device *drm,
> +				     struct sunxi_engine *engine);
> +#endif /* _SUN8I_LAYER_H_ */
> diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.c b/drivers/gpu/drm/sun4i/sun8i_mixer.c
> new file mode 100644
> index 000000000000..e216b84d5bb2
> --- /dev/null
> +++ b/drivers/gpu/drm/sun4i/sun8i_mixer.c
> @@ -0,0 +1,394 @@
> +/*
> + * Copyright (C) 2017 Icenowy Zheng <icenowy@xxxxxxx>
> + *
> + * Based on sun4i_backend.c, which is:
> + *   Copyright (C) 2015 Free Electrons
> + *   Copyright (C) 2015 NextThing Co
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_fb_cma_helper.h>
> +#include <drm/drm_gem_cma_helper.h>
> +#include <drm/drm_plane_helper.h>
> +
> +#include <linux/component.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/reset.h>
> +#include <linux/of_device.h>
> +
> +#include "sun4i_drv.h"
> +#include "sun8i_mixer.h"
> +#include "sun8i_layer.h"
> +#include "sunxi_engine.h"
> +
> +void sun8i_mixer_commit(struct sunxi_engine *engine)
> +{
> +	DRM_DEBUG_DRIVER("Committing changes\n");
> +
> +	regmap_write(engine->regs, SUN8I_MIXER_GLOBAL_DBUFF,
> +		     SUN8I_MIXER_GLOBAL_DBUFF_ENABLE);
> +}

This function can be static

> +
> +void sun8i_mixer_layer_enable(struct sun8i_mixer *mixer,
> +				int layer, bool enable)
> +{
> +	u32 val;
> +	/* Currently the first UI channel is used */
> +	int chan = mixer->cfg->vi_num;
> +
> +	DRM_DEBUG_DRIVER("Enabling layer %d in channel %d\n", layer, chan);
> +
> +	if (enable)
> +		val = SUN8I_MIXER_CHAN_UI_LAYER_ATTR_EN;
> +	else
> +		val = 0;
> +
> +	regmap_update_bits(mixer->engine.regs,
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR(chan, layer),
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR_EN, val);
> +
> +	/* Set the alpha configuration */
> +	regmap_update_bits(mixer->engine.regs,
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR(chan, layer),
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA_MODE_MASK,
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA_MODE_DEF);
> +	regmap_update_bits(mixer->engine.regs,
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR(chan, layer),
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA_MASK,
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA_DEF);
> +}

This one too.

> +static int sun8i_mixer_drm_format_to_layer(struct drm_plane *plane,
> +					     u32 format, u32 *mode)
> +{
> +	switch (format) {
> +	case DRM_FORMAT_XRGB8888:
> +		*mode = SUN8I_MIXER_CHAN_UI_LAYER_ATTR_FBFMT_XRGB8888;
> +		break;
> +
> +	case DRM_FORMAT_RGB888:
> +		*mode = SUN8I_MIXER_CHAN_UI_LAYER_ATTR_FBFMT_RGB888;
> +		break;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +int sun8i_mixer_update_layer_coord(struct sun8i_mixer *mixer,
> +				     int layer, struct drm_plane *plane)
> +{
> +	struct drm_plane_state *state = plane->state;
> +	struct drm_framebuffer *fb = state->fb;
> +	/* Currently the first UI channel is used */
> +	int chan = mixer->cfg->vi_num;
> +
> +	DRM_DEBUG_DRIVER("Updating layer %d\n", layer);
> +
> +	if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
> +		DRM_DEBUG_DRIVER("Primary layer, updating global size W: %u H: %u\n",
> +				 state->crtc_w, state->crtc_h);
> +		regmap_write(mixer->engine.regs, SUN8I_MIXER_GLOBAL_SIZE,
> +			     SUN8I_MIXER_SIZE(state->crtc_w,
> +					      state->crtc_h));
> +		DRM_DEBUG_DRIVER("Updating blender size\n");
> +		regmap_write(mixer->engine.regs,
> +			     SUN8I_MIXER_BLEND_ATTR_INSIZE(0),
> +			     SUN8I_MIXER_SIZE(state->crtc_w,
> +					      state->crtc_h));
> +		regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_OUTSIZE,
> +			     SUN8I_MIXER_SIZE(state->crtc_w,
> +					      state->crtc_h));
> +		DRM_DEBUG_DRIVER("Updating channel size\n");
> +		regmap_write(mixer->engine.regs,
> +			     SUN8I_MIXER_CHAN_UI_OVL_SIZE(chan),
> +			     SUN8I_MIXER_SIZE(state->crtc_w,
> +					      state->crtc_h));
> +	}
> +
> +	/* Set the line width */
> +	DRM_DEBUG_DRIVER("Layer line width: %d bytes\n", fb->pitches[0]);
> +	regmap_write(mixer->engine.regs,
> +		     SUN8I_MIXER_CHAN_UI_LAYER_PITCH(chan, layer),
> +		     fb->pitches[0]);
> +
> +	/* Set height and width */
> +	DRM_DEBUG_DRIVER("Layer size W: %u H: %u\n",
> +			 state->crtc_w, state->crtc_h);
> +	regmap_write(mixer->engine.regs,
> +		     SUN8I_MIXER_CHAN_UI_LAYER_SIZE(chan, layer),
> +		     SUN8I_MIXER_SIZE(state->crtc_w, state->crtc_h));
> +
> +	/* Set base coordinates */
> +	DRM_DEBUG_DRIVER("Layer coordinates X: %d Y: %d\n",
> +			 state->crtc_x, state->crtc_y);
> +	regmap_write(mixer->engine.regs,
> +		     SUN8I_MIXER_CHAN_UI_LAYER_COORD(chan, layer),
> +		     SUN8I_MIXER_COORD(state->crtc_x, state->crtc_y));

X and Y are fixed point numbers. You want to keep only the higher 16
bits there.

> +
> +	return 0;
> +}
> +
> +int sun8i_mixer_update_layer_formats(struct sun8i_mixer *mixer,
> +				       int layer, struct drm_plane *plane)
> +{
> +	struct drm_plane_state *state = plane->state;
> +	struct drm_framebuffer *fb = state->fb;
> +	bool interlaced = false;
> +	u32 val;
> +	/* Currently the first UI channel is used */
> +	int chan = mixer->cfg->vi_num;
> +	int ret;
> +
> +	if (plane->state->crtc)
> +		interlaced = plane->state->crtc->state->adjusted_mode.flags
> +			& DRM_MODE_FLAG_INTERLACE;
> +
> +	regmap_update_bits(mixer->engine.regs, SUN8I_MIXER_BLEND_OUTCTL,
> +			   SUN8I_MIXER_BLEND_OUTCTL_INTERLACED,
> +			   interlaced ?
> +			   SUN8I_MIXER_BLEND_OUTCTL_INTERLACED : 0);
> +
> +	DRM_DEBUG_DRIVER("Switching display mixer interlaced mode %s\n",
> +			 interlaced ? "on" : "off");
> +
> +	ret = sun8i_mixer_drm_format_to_layer(plane, fb->format->format,
> +						&val);
> +	if (ret) {
> +		DRM_DEBUG_DRIVER("Invalid format\n");
> +		return ret;
> +	}
> +
> +	regmap_update_bits(mixer->engine.regs,
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR(chan, layer),
> +			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR_FBFMT_MASK, val);
> +
> +	return 0;
> +}
> +
> +int sun8i_mixer_update_layer_buffer(struct sun8i_mixer *mixer,
> +				      int layer, struct drm_plane *plane)
> +{
> +	struct drm_plane_state *state = plane->state;
> +	struct drm_framebuffer *fb = state->fb;
> +	struct drm_gem_cma_object *gem;
> +	dma_addr_t paddr;
> +	/* Currently the first UI channel is used */
> +	int chan = mixer->cfg->vi_num;
> +	int bpp;
> +
> +	/* Get the physical address of the buffer in memory */
> +	gem = drm_fb_cma_get_gem_obj(fb, 0);
> +
> +	DRM_DEBUG_DRIVER("Using GEM @ %pad\n", &gem->paddr);
> +
> +	/* Compute the start of the displayed memory */
> +	bpp = fb->format->cpp[0];
> +	paddr = gem->paddr + fb->offsets[0];
> +	paddr += (state->src_x >> 16) * bpp;
> +	paddr += (state->src_y >> 16) * fb->pitches[0];
> +
> +	DRM_DEBUG_DRIVER("Setting buffer address to %pad\n", &paddr);
> +
> +	regmap_write(mixer->engine.regs,
> +		     SUN8I_MIXER_CHAN_UI_LAYER_TOP_LADDR(chan, layer),
> +		     lower_32_bits(paddr));
> +
> +	return 0;
> +}
> +
> +static const struct sunxi_engine_ops sun8i_engine_ops = {
> +	.commit		= sun8i_mixer_commit,
> +	.layers_init	= sun8i_layers_init,
> +};
> +
> +static struct regmap_config sun8i_mixer_regmap_config = {
> +	.reg_bits	= 32,
> +	.val_bits	= 32,
> +	.reg_stride	= 4,
> +	.max_register	= 0xbfffc, /* guessed */
> +};
> +
> +static int sun8i_mixer_bind(struct device *dev, struct device *master,
> +			      void *data)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct drm_device *drm = data;
> +	struct sun4i_drv *drv = drm->dev_private;
> +	struct sun8i_mixer *mixer;
> +	struct resource *res;
> +	void __iomem *regs;
> +	int i, ret;
> +
> +	/*
> +	 * The mixer uses single 32-bit register to store memory
> +	 * addresses, so that it cannot deal with 64-bit memory
> +	 * addresses.
> +	 * Restrict the DMA mask so that the mixer won't be
> +	 * allocated some memory that is too high.
> +	 */
> +	ret = dma_set_mask(dev, DMA_BIT_MASK(32));
> +	if (ret) {
> +		dev_err(dev, "Cannot do 32-bit DMA.\n");
> +		return ret;
> +	}
> +
> +	mixer = devm_kzalloc(dev, sizeof(*mixer), GFP_KERNEL);
> +	if (!mixer)
> +		return -ENOMEM;
> +	dev_set_drvdata(dev, mixer);
> +	mixer->engine.ops = &sun8i_engine_ops;
> +	mixer->engine.node = dev->of_node;
> +
> +	mixer->cfg = of_device_get_match_data(dev);
> +	if (!mixer->cfg)
> +		return -EINVAL;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	regs = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(regs))
> +		return PTR_ERR(regs);
> +
> +	mixer->engine.regs = devm_regmap_init_mmio(dev, regs,
> +						   &sun8i_mixer_regmap_config);
> +	if (IS_ERR(mixer->engine.regs)) {
> +		dev_err(dev, "Couldn't create the mixer regmap\n");
> +		return PTR_ERR(mixer->engine.regs);
> +	}
> +
> +	mixer->reset = devm_reset_control_get(dev, NULL);
> +	if (IS_ERR(mixer->reset)) {
> +		dev_err(dev, "Couldn't get our reset line\n");
> +		return PTR_ERR(mixer->reset);
> +	}
> +
> +	ret = reset_control_deassert(mixer->reset);
> +	if (ret) {
> +		dev_err(dev, "Couldn't deassert our reset line\n");
> +		return ret;
> +	}
> +
> +	mixer->bus_clk = devm_clk_get(dev, "bus");
> +	if (IS_ERR(mixer->bus_clk)) {
> +		dev_err(dev, "Couldn't get the mixer bus clock\n");
> +		ret = PTR_ERR(mixer->bus_clk);
> +		goto err_assert_reset;
> +	}
> +	clk_prepare_enable(mixer->bus_clk);
> +
> +	mixer->mod_clk = devm_clk_get(dev, "mod");
> +	if (IS_ERR(mixer->mod_clk)) {
> +		dev_err(dev, "Couldn't get the mixer module clock\n");
> +		ret = PTR_ERR(mixer->mod_clk);
> +		goto err_disable_bus_clk;
> +	}
> +	clk_prepare_enable(mixer->mod_clk);
> +
> +	list_add_tail(&mixer->engine.list, &drv->engine_list);

You didn't call INIT_LIST_HEAD on that list.

> +
> +	/* Reset the registers */
> +	for (i = 0x0; i < 0x20000; i += 4)
> +		regmap_write(mixer->engine.regs, i, 0);
> +
> +	/* Enable the mixer */
> +	regmap_write(mixer->engine.regs, SUN8I_MIXER_GLOBAL_CTL,
> +		     SUN8I_MIXER_GLOBAL_CTL_RT_EN);
> +
> +	/* Initialize blender */
> +	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_FCOLOR_CTL,
> +		     SUN8I_MIXER_BLEND_FCOLOR_CTL_DEF);
> +	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_PREMULTIPLY,
> +		     SUN8I_MIXER_BLEND_PREMULTIPLY_DEF);
> +	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_BKCOLOR,
> +		     SUN8I_MIXER_BLEND_BKCOLOR_DEF);
> +	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_MODE(0),
> +		     SUN8I_MIXER_BLEND_MODE_DEF);
> +	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_CK_CTL,
> +		     SUN8I_MIXER_BLEND_CK_CTL_DEF);
> +
> +	regmap_write(mixer->engine.regs,
> +		     SUN8I_MIXER_BLEND_ATTR_FCOLOR(0),
> +		     SUN8I_MIXER_BLEND_ATTR_FCOLOR_DEF);
> +
> +	/* Select the first UI channel */
> +	DRM_DEBUG_DRIVER("Selecting channel %d (first UI channel)\n",
> +			 mixer->cfg->vi_num);
> +	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_ROUTE,
> +		     mixer->cfg->vi_num);
> +
> +	return 0;
> +
> +	clk_disable_unprepare(mixer->mod_clk);

This line cannot be reached.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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