Re: [PATCH v2 15/17] drm/vc4: tests: Introduce a mocking infrastructure

["Maíra Canal" <mcanal@igalia.com>]

On 11/28/22 11:53, Maxime Ripard wrote:
> In order to test the current atomic_check hooks we need to have a DRM
> device that has roughly the same capabilities and layout that the actual
> hardware. We'll also need a bunch of functions to create arbitrary
> atomic states.
> 
> Let's create some helpers to create a device that behaves like the real
> one, and some helpers to maintain the atomic state we want to check.
> 
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> ---
>  drivers/gpu/drm/vc4/Kconfig                 |  15 +++
>  drivers/gpu/drm/vc4/Makefile                |   6 +
>  drivers/gpu/drm/vc4/tests/.kunitconfig      |  14 ++
>  drivers/gpu/drm/vc4/tests/vc4_mock.c        | 200 ++++++++++++++++++++++++++++
>  drivers/gpu/drm/vc4/tests/vc4_mock.h        |  60 +++++++++
>  drivers/gpu/drm/vc4/tests/vc4_mock_crtc.c   |  41 ++++++
>  drivers/gpu/drm/vc4/tests/vc4_mock_output.c |  99 ++++++++++++++
>  drivers/gpu/drm/vc4/tests/vc4_mock_plane.c  |  47 +++++++
>  drivers/gpu/drm/vc4/vc4_crtc.c              |  20 +--
>  drivers/gpu/drm/vc4/vc4_drv.c               |   4 +-
>  drivers/gpu/drm/vc4/vc4_drv.h               |  16 +++
>  drivers/gpu/drm/vc4/vc4_txp.c               |   2 +-
>  12 files changed, 511 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vc4/Kconfig b/drivers/gpu/drm/vc4/Kconfig
> index 246305d17a52..dcdcc9e5cac4 100644
> --- a/drivers/gpu/drm/vc4/Kconfig
> +++ b/drivers/gpu/drm/vc4/Kconfig
> @@ -34,3 +34,18 @@ config DRM_VC4_HDMI_CEC
>  	help
>  	  Choose this option if you have a Broadcom VC4 GPU
>  	  and want to use CEC.
> +
> +config DRM_VC4_KUNIT_TEST
> +	bool "KUnit tests for VC4" if !KUNIT_ALL_TESTS
> +	depends on DRM_VC4 && KUNIT
> +	default KUNIT_ALL_TESTS
> +	help
> +	  This builds unit tests for the VC4 DRM/KMS driver. This option is
> +	  not useful for distributions or general kernels, but only for kernel
> +	  developers working on the VC4 driver.
> +
> +	  For more information on KUnit and unit tests in general,
> +	  please refer to the KUnit documentation in
> +	  Documentation/dev-tools/kunit/.
> +
> +	  If in doubt, say "N".
> diff --git a/drivers/gpu/drm/vc4/Makefile b/drivers/gpu/drm/vc4/Makefile
> index d0163e18e9ca..f974a8c80e2f 100644
> --- a/drivers/gpu/drm/vc4/Makefile
> +++ b/drivers/gpu/drm/vc4/Makefile
> @@ -25,6 +25,12 @@ vc4-y := \
>  	vc4_validate.o \
>  	vc4_validate_shaders.o
>  
> +vc4-$(CONFIG_DRM_VC4_KUNIT_TEST) += \
> +	tests/vc4_mock.o \
> +	tests/vc4_mock_crtc.o \
> +	tests/vc4_mock_output.o \
> +	tests/vc4_mock_plane.o
> +
>  vc4-$(CONFIG_DEBUG_FS) += vc4_debugfs.o
>  
>  obj-$(CONFIG_DRM_VC4)  += vc4.o
> diff --git a/drivers/gpu/drm/vc4/tests/.kunitconfig b/drivers/gpu/drm/vc4/tests/.kunitconfig
> new file mode 100644
> index 000000000000..bfd9899ed6e0
> --- /dev/null
> +++ b/drivers/gpu/drm/vc4/tests/.kunitconfig
> @@ -0,0 +1,14 @@
> +CONFIG_ARCH_BCM=y
> +CONFIG_ARCH_BCM2835=y
> +CONFIG_BCM2835_MBOX=y
> +CONFIG_KUNIT=y
> +CONFIG_DRM=y
> +CONFIG_DRM_KUNIT_TEST=y

I'm not sure if it makes sense to run the DRM tests here as well. Maybe
it would be better to separate the compilation of the drm_kunit_helpers
from the compilation of the rest of the DRM tests. This way, this
Kconfig entry could be dropped and only the vc4 tests would run.
Moreover, it would allow to run the vc4 tests with --arch=arm.

Best Regards,
- Maíra Canal

> +CONFIG_DRM_VC4=y
> +CONFIG_DRM_VC4_KUNIT_TEST=y
> +CONFIG_MAILBOX=y
> +CONFIG_RASPBERRYPI_FIRMWARE=y
> +CONFIG_SND=y
> +CONFIG_SND_SOC=y
> +CONFIG_SOUND=y
> +CONFIG_COMMON_CLK=y
> diff --git a/drivers/gpu/drm/vc4/tests/vc4_mock.c b/drivers/gpu/drm/vc4/tests/vc4_mock.c
> new file mode 100644
> index 000000000000..a4bed26af32f
> --- /dev/null
> +++ b/drivers/gpu/drm/vc4/tests/vc4_mock.c
> @@ -0,0 +1,200 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <drm/drm_drv.h>
> +#include <drm/drm_kunit_helpers.h>
> +
> +#include <kunit/test.h>
> +
> +#include "vc4_mock.h"
> +
> +struct vc4_mock_output_desc {
> +	enum vc4_encoder_type	vc4_encoder_type;
> +	unsigned int		encoder_type;
> +	unsigned int		connector_type;
> +};
> +
> +#define VC4_MOCK_OUTPUT_DESC(_vc4_type, _etype, _ctype)					\
> +	{										\
> +		.vc4_encoder_type = _vc4_type,						\
> +		.encoder_type = _etype,							\
> +		.connector_type = _ctype,						\
> +	}
> +
> +struct vc4_mock_pipe_desc {
> +	const struct vc4_crtc_data *data;
> +	const struct vc4_mock_output_desc *outputs;
> +	unsigned int noutputs;
> +};
> +
> +#define VC4_MOCK_CRTC_DESC(_data, ...)							\
> +	{										\
> +		.data = _data,								\
> +		.outputs = (struct vc4_mock_output_desc[]) { __VA_ARGS__ },		\
> +		.noutputs = sizeof((struct vc4_mock_output_desc[]) { __VA_ARGS__ }) /	\
> +			     sizeof(struct vc4_mock_output_desc),			\
> +	}
> +
> +#define VC4_MOCK_PIXELVALVE_DESC(_data, ...)						\
> +	VC4_MOCK_CRTC_DESC(&(_data)->base, __VA_ARGS__)
> +
> +struct vc4_mock_desc {
> +	const struct vc4_mock_pipe_desc *pipes;
> +	unsigned int npipes;
> +};
> +
> +#define VC4_MOCK_DESC(...)								\
> +	{										\
> +		.pipes = (struct vc4_mock_pipe_desc[]) { __VA_ARGS__ },			\
> +		.npipes = sizeof((struct vc4_mock_pipe_desc[]) { __VA_ARGS__ }) /	\
> +			     sizeof(struct vc4_mock_pipe_desc),				\
> +	}
> +
> +static const struct vc4_mock_desc vc4_mock =
> +	VC4_MOCK_DESC(
> +		VC4_MOCK_CRTC_DESC(&vc4_txp_crtc_data,
> +				   VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_TXP,
> +							DRM_MODE_ENCODER_VIRTUAL,
> +							DRM_MODE_CONNECTOR_WRITEBACK)),
> +		VC4_MOCK_PIXELVALVE_DESC(&bcm2835_pv0_data,
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_DSI0,
> +							      DRM_MODE_ENCODER_DSI,
> +							      DRM_MODE_CONNECTOR_DSI),
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_DPI,
> +							      DRM_MODE_ENCODER_DPI,
> +							      DRM_MODE_CONNECTOR_DPI)),
> +		VC4_MOCK_PIXELVALVE_DESC(&bcm2835_pv1_data,
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_DSI1,
> +							      DRM_MODE_ENCODER_DSI,
> +							      DRM_MODE_CONNECTOR_DSI)),
> +		VC4_MOCK_PIXELVALVE_DESC(&bcm2835_pv2_data,
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_HDMI0,
> +							      DRM_MODE_ENCODER_TMDS,
> +							      DRM_MODE_CONNECTOR_HDMIA),
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_VEC,
> +							      DRM_MODE_ENCODER_TVDAC,
> +							      DRM_MODE_CONNECTOR_Composite)),
> +);
> +
> +static const struct vc4_mock_desc vc5_mock =
> +	VC4_MOCK_DESC(
> +		VC4_MOCK_CRTC_DESC(&vc4_txp_crtc_data,
> +				   VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_TXP,
> +							DRM_MODE_ENCODER_VIRTUAL,
> +							DRM_MODE_CONNECTOR_WRITEBACK)),
> +		VC4_MOCK_PIXELVALVE_DESC(&bcm2711_pv0_data,
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_DSI0,
> +							      DRM_MODE_ENCODER_DSI,
> +							      DRM_MODE_CONNECTOR_DSI),
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_DPI,
> +							      DRM_MODE_ENCODER_DPI,
> +							      DRM_MODE_CONNECTOR_DPI)),
> +		VC4_MOCK_PIXELVALVE_DESC(&bcm2711_pv1_data,
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_DSI1,
> +							      DRM_MODE_ENCODER_DSI,
> +							      DRM_MODE_CONNECTOR_DSI)),
> +		VC4_MOCK_PIXELVALVE_DESC(&bcm2711_pv2_data,
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_HDMI0,
> +							      DRM_MODE_ENCODER_TMDS,
> +							      DRM_MODE_CONNECTOR_HDMIA)),
> +		VC4_MOCK_PIXELVALVE_DESC(&bcm2711_pv3_data,
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_VEC,
> +							      DRM_MODE_ENCODER_TVDAC,
> +							      DRM_MODE_CONNECTOR_Composite)),
> +		VC4_MOCK_PIXELVALVE_DESC(&bcm2711_pv4_data,
> +					 VC4_MOCK_OUTPUT_DESC(VC4_ENCODER_TYPE_HDMI1,
> +							      DRM_MODE_ENCODER_TMDS,
> +							      DRM_MODE_CONNECTOR_HDMIA)),
> +);
> +
> +static int __build_one_pipe(struct kunit *test, struct drm_device *drm,
> +			    const struct vc4_mock_pipe_desc *pipe)
> +{
> +	struct vc4_dummy_plane *dummy_plane;
> +	struct drm_plane *plane;
> +	struct vc4_dummy_crtc *dummy_crtc;
> +	struct drm_crtc *crtc;
> +	unsigned int i;
> +
> +	dummy_plane = vc4_dummy_plane(test, drm, DRM_PLANE_TYPE_PRIMARY);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dummy_plane);
> +
> +	plane = &dummy_plane->plane.base;
> +	dummy_crtc = vc4_mock_pv(test, drm, plane, pipe->data);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dummy_crtc);
> +
> +	crtc = &dummy_crtc->crtc.base;
> +	for (i = 0; i < pipe->noutputs; i++) {
> +		const struct vc4_mock_output_desc *mock_output = &pipe->outputs[i];
> +		struct vc4_dummy_output *dummy_output;
> +
> +		dummy_output = vc4_dummy_output(test, drm, crtc,
> +						mock_output->vc4_encoder_type,
> +						mock_output->encoder_type,
> +						mock_output->connector_type);
> +		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dummy_output);
> +	}
> +
> +	return 0;
> +}
> +
> +static int __build_mock(struct kunit *test, struct drm_device *drm,
> +			const struct vc4_mock_desc *mock)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < mock->npipes; i++) {
> +		const struct vc4_mock_pipe_desc *pipe = &mock->pipes[i];
> +		int ret;
> +
> +		ret = __build_one_pipe(test, drm, pipe);
> +		KUNIT_ASSERT_EQ(test, ret, 0);
> +	}
> +
> +	return 0;
> +}
> +
> +static struct vc4_dev *__mock_device(struct kunit *test, bool is_vc5)
> +{
> +	struct drm_device *drm;
> +	const struct drm_driver *drv = is_vc5 ? &vc5_drm_driver : &vc4_drm_driver;
> +	const struct vc4_mock_desc *desc = is_vc5 ? &vc5_mock : &vc4_mock;
> +	struct vc4_dev *vc4;
> +	struct device *dev;
> +	int ret;
> +
> +	dev = drm_kunit_helper_alloc_device(test);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
> +
> +	vc4 = drm_kunit_helper_alloc_drm_device_with_driver(test, dev,
> +							    struct vc4_dev, base,
> +							    drv);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, vc4);
> +
> +	vc4->dev = dev;
> +	vc4->is_vc5 = is_vc5;
> +
> +	vc4->hvs = __vc4_hvs_alloc(vc4, NULL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, vc4->hvs);
> +
> +	drm = &vc4->base;
> +	ret = __build_mock(test, drm, desc);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	ret = vc4_kms_load(drm);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	ret = drm_dev_register(drm, 0);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	return vc4;
> +}
> +
> +struct vc4_dev *vc4_mock_device(struct kunit *test)
> +{
> +	return __mock_device(test, false);
> +}
> +
> +struct vc4_dev *vc5_mock_device(struct kunit *test)
> +{
> +	return __mock_device(test, true);
> +}
> diff --git a/drivers/gpu/drm/vc4/tests/vc4_mock.h b/drivers/gpu/drm/vc4/tests/vc4_mock.h
> new file mode 100644
> index 000000000000..ace5b2e00f4a
> --- /dev/null
> +++ b/drivers/gpu/drm/vc4/tests/vc4_mock.h
> @@ -0,0 +1,60 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef VC4_MOCK_H_
> +#define VC4_MOCK_H_
> +
> +#include "../vc4_drv.h"
> +
> +static inline
> +struct drm_crtc *vc4_find_crtc_for_encoder(struct kunit *test,
> +					   struct drm_device *drm,
> +					   struct drm_encoder *encoder)
> +{
> +	struct drm_crtc *crtc;
> +
> +	KUNIT_ASSERT_EQ(test, hweight32(encoder->possible_crtcs), 1);
> +
> +	drm_for_each_crtc(crtc, drm)
> +		if (encoder->possible_crtcs & drm_crtc_mask(crtc))
> +			return crtc;
> +
> +	return NULL;
> +}
> +
> +struct vc4_dummy_plane {
> +	struct vc4_plane plane;
> +};
> +
> +struct vc4_dummy_plane *vc4_dummy_plane(struct kunit *test,
> +					struct drm_device *drm,
> +					enum drm_plane_type type);
> +
> +struct vc4_dummy_crtc {
> +	struct vc4_crtc crtc;
> +};
> +
> +struct vc4_dummy_crtc *vc4_mock_pv(struct kunit *test,
> +				   struct drm_device *drm,
> +				   struct drm_plane *plane,
> +				   const struct vc4_crtc_data *data);
> +
> +struct vc4_dummy_output {
> +	struct vc4_encoder encoder;
> +	struct drm_connector connector;
> +};
> +
> +struct vc4_dummy_output *vc4_dummy_output(struct kunit *test,
> +					  struct drm_device *drm,
> +					  struct drm_crtc *crtc,
> +					  enum vc4_encoder_type vc4_encoder_type,
> +					  unsigned int kms_encoder_type,
> +					  unsigned int connector_type);
> +
> +struct vc4_dev *vc4_mock_device(struct kunit *test);
> +struct vc4_dev *vc5_mock_device(struct kunit *test);
> +
> +int vc4_mock_atomic_add_output(struct kunit *test, struct drm_device *drm,
> +			       enum vc4_encoder_type type,
> +			       struct drm_atomic_state *state);
> +
> +#endif // VC4_MOCK_H_
> diff --git a/drivers/gpu/drm/vc4/tests/vc4_mock_crtc.c b/drivers/gpu/drm/vc4/tests/vc4_mock_crtc.c
> new file mode 100644
> index 000000000000..5d12d7beef0e
> --- /dev/null
> +++ b/drivers/gpu/drm/vc4/tests/vc4_mock_crtc.c
> @@ -0,0 +1,41 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <drm/drm_atomic_state_helper.h>
> +#include <drm/drm_modeset_helper_vtables.h>
> +
> +#include <kunit/test.h>
> +
> +#include "vc4_mock.h"
> +
> +static const struct drm_crtc_helper_funcs vc4_dummy_crtc_helper_funcs = {
> +	.atomic_check	= vc4_crtc_atomic_check,
> +};
> +
> +static const struct drm_crtc_funcs vc4_dummy_crtc_funcs = {
> +	.atomic_destroy_state	= vc4_crtc_destroy_state,
> +	.atomic_duplicate_state	= vc4_crtc_duplicate_state,
> +	.reset			= vc4_crtc_reset,
> +};
> +
> +struct vc4_dummy_crtc *vc4_mock_pv(struct kunit *test,
> +				   struct drm_device *drm,
> +				   struct drm_plane *plane,
> +				   const struct vc4_crtc_data *data)
> +{
> +	struct vc4_dummy_crtc *dummy_crtc;
> +	struct vc4_crtc *vc4_crtc;
> +	int ret;
> +
> +	dummy_crtc = kunit_kzalloc(test, sizeof(*dummy_crtc), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_NULL(test, dummy_crtc);
> +
> +	vc4_crtc = &dummy_crtc->crtc;
> +	ret = __vc4_crtc_init(drm, NULL,
> +			      vc4_crtc, data, plane,
> +			      &vc4_dummy_crtc_funcs,
> +			      &vc4_dummy_crtc_helper_funcs,
> +			      false);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	return dummy_crtc;
> +}
> diff --git a/drivers/gpu/drm/vc4/tests/vc4_mock_output.c b/drivers/gpu/drm/vc4/tests/vc4_mock_output.c
> new file mode 100644
> index 000000000000..cb16ab4451f7
> --- /dev/null
> +++ b/drivers/gpu/drm/vc4/tests/vc4_mock_output.c
> @@ -0,0 +1,99 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <drm/drm_atomic_state_helper.h>
> +#include <drm/drm_atomic_uapi.h>
> +#include <drm/drm_connector.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_encoder.h>
> +#include <drm/drm_modeset_helper_vtables.h>
> +
> +#include <kunit/test.h>
> +
> +#include "vc4_mock.h"
> +
> +static const struct drm_connector_helper_funcs vc4_dummy_connector_helper_funcs = {
> +};
> +
> +static const struct drm_connector_funcs vc4_dummy_connector_funcs = {
> +	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
> +	.atomic_duplicate_state	= drm_atomic_helper_connector_duplicate_state,
> +	.reset			= drm_atomic_helper_connector_reset,
> +};
> +
> +struct vc4_dummy_output *vc4_dummy_output(struct kunit *test,
> +					  struct drm_device *drm,
> +					  struct drm_crtc *crtc,
> +					  enum vc4_encoder_type vc4_encoder_type,
> +					  unsigned int kms_encoder_type,
> +					  unsigned int connector_type)
> +{
> +	struct vc4_dummy_output *dummy_output;
> +	struct drm_connector *conn;
> +	struct drm_encoder *enc;
> +	int ret;
> +
> +	dummy_output = kunit_kzalloc(test, sizeof(*dummy_output), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dummy_output);
> +	dummy_output->encoder.type = vc4_encoder_type;
> +
> +	enc = &dummy_output->encoder.base;
> +	ret = drmm_encoder_init(drm, enc,
> +				NULL,
> +				kms_encoder_type,
> +				NULL);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +	enc->possible_crtcs = drm_crtc_mask(crtc);
> +
> +	conn = &dummy_output->connector;
> +	ret = drmm_connector_init(drm, conn,
> +				  &vc4_dummy_connector_funcs,
> +				  connector_type,
> +				  NULL);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	drm_connector_helper_add(conn, &vc4_dummy_connector_helper_funcs);
> +	drm_connector_attach_encoder(conn, enc);
> +
> +	return dummy_output;
> +}
> +
> +static const struct drm_display_mode default_mode = {
> +	DRM_SIMPLE_MODE(640, 480, 64, 48)
> +};
> +
> +int vc4_mock_atomic_add_output(struct kunit *test, struct drm_device *drm,
> +			       enum vc4_encoder_type type,
> +			       struct drm_atomic_state *state)
> +{
> +	struct vc4_dummy_output *output;
> +	struct drm_connector *conn;
> +	struct drm_connector_state *conn_state;
> +	struct drm_encoder *encoder;
> +	struct drm_crtc *crtc;
> +	struct drm_crtc_state *crtc_state;
> +	int ret;
> +
> +	encoder = vc4_find_encoder_by_type(drm, type);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, encoder);
> +
> +	crtc = vc4_find_crtc_for_encoder(test, drm, encoder);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, crtc);
> +
> +	output = container_of(encoder, struct vc4_dummy_output, encoder.base);
> +	conn = &output->connector;
> +	conn_state = drm_atomic_get_connector_state(state, conn);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, conn_state);
> +
> +	ret = drm_atomic_set_crtc_for_connector(conn_state, crtc);
> +	KUNIT_EXPECT_EQ(test, ret, 0);
> +
> +	crtc_state = drm_atomic_get_crtc_state(state, crtc);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, crtc_state);
> +
> +	ret = drm_atomic_set_mode_for_crtc(crtc_state, &default_mode);
> +	KUNIT_EXPECT_EQ(test, ret, 0);
> +
> +	crtc_state->active = true;
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/vc4/tests/vc4_mock_plane.c b/drivers/gpu/drm/vc4/tests/vc4_mock_plane.c
> new file mode 100644
> index 000000000000..62b18f5f41db
> --- /dev/null
> +++ b/drivers/gpu/drm/vc4/tests/vc4_mock_plane.c
> @@ -0,0 +1,47 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <drm/drm_atomic_state_helper.h>
> +#include <drm/drm_fourcc.h>
> +#include <drm/drm_modeset_helper_vtables.h>
> +#include <drm/drm_plane.h>
> +
> +#include <kunit/test.h>
> +
> +#include "vc4_mock.h"
> +
> +static const struct drm_plane_helper_funcs vc4_dummy_plane_helper_funcs = {
> +};
> +
> +static const struct drm_plane_funcs vc4_dummy_plane_funcs = {
> +	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
> +	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
> +	.reset			= drm_atomic_helper_plane_reset,
> +};
> +
> +static const uint32_t vc4_dummy_plane_formats[] = {
> +	DRM_FORMAT_XRGB8888,
> +};
> +
> +struct vc4_dummy_plane *vc4_dummy_plane(struct kunit *test,
> +					struct drm_device *drm,
> +					enum drm_plane_type type)
> +{
> +	struct vc4_dummy_plane *dummy_plane;
> +	struct drm_plane *plane;
> +
> +	dummy_plane = drmm_universal_plane_alloc(drm,
> +						 struct vc4_dummy_plane, plane.base,
> +						 0,
> +						 &vc4_dummy_plane_funcs,
> +						 vc4_dummy_plane_formats,
> +						 ARRAY_SIZE(vc4_dummy_plane_formats),
> +						 NULL,
> +						 DRM_PLANE_TYPE_PRIMARY,
> +						 NULL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dummy_plane);
> +
> +	plane = &dummy_plane->plane.base;
> +	drm_plane_helper_add(plane, &vc4_dummy_plane_helper_funcs);
> +
> +	return dummy_plane;
> +}
> diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
> index 59e473059fa2..21b40d644ace 100644
> --- a/drivers/gpu/drm/vc4/vc4_crtc.c
> +++ b/drivers/gpu/drm/vc4/vc4_crtc.c
> @@ -675,8 +675,8 @@ void vc4_crtc_get_margins(struct drm_crtc_state *state,
>  	}
>  }
>  
> -static int vc4_crtc_atomic_check(struct drm_crtc *crtc,
> -				 struct drm_atomic_state *state)
> +int vc4_crtc_atomic_check(struct drm_crtc *crtc,
> +			  struct drm_atomic_state *state)
>  {
>  	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
>  									  crtc);
> @@ -1116,7 +1116,7 @@ static const struct drm_crtc_helper_funcs vc4_crtc_helper_funcs = {
>  	.get_scanout_position = vc4_crtc_get_scanout_position,
>  };
>  
> -static const struct vc4_pv_data bcm2835_pv0_data = {
> +const struct vc4_pv_data bcm2835_pv0_data = {
>  	.base = {
>  		.name = "pixelvalve-0",
>  		.debugfs_name = "crtc0_regs",
> @@ -1131,7 +1131,7 @@ static const struct vc4_pv_data bcm2835_pv0_data = {
>  	},
>  };
>  
> -static const struct vc4_pv_data bcm2835_pv1_data = {
> +const struct vc4_pv_data bcm2835_pv1_data = {
>  	.base = {
>  		.name = "pixelvalve-1",
>  		.debugfs_name = "crtc1_regs",
> @@ -1146,7 +1146,7 @@ static const struct vc4_pv_data bcm2835_pv1_data = {
>  	},
>  };
>  
> -static const struct vc4_pv_data bcm2835_pv2_data = {
> +const struct vc4_pv_data bcm2835_pv2_data = {
>  	.base = {
>  		.name = "pixelvalve-2",
>  		.debugfs_name = "crtc2_regs",
> @@ -1161,7 +1161,7 @@ static const struct vc4_pv_data bcm2835_pv2_data = {
>  	},
>  };
>  
> -static const struct vc4_pv_data bcm2711_pv0_data = {
> +const struct vc4_pv_data bcm2711_pv0_data = {
>  	.base = {
>  		.name = "pixelvalve-0",
>  		.debugfs_name = "crtc0_regs",
> @@ -1176,7 +1176,7 @@ static const struct vc4_pv_data bcm2711_pv0_data = {
>  	},
>  };
>  
> -static const struct vc4_pv_data bcm2711_pv1_data = {
> +const struct vc4_pv_data bcm2711_pv1_data = {
>  	.base = {
>  		.name = "pixelvalve-1",
>  		.debugfs_name = "crtc1_regs",
> @@ -1191,7 +1191,7 @@ static const struct vc4_pv_data bcm2711_pv1_data = {
>  	},
>  };
>  
> -static const struct vc4_pv_data bcm2711_pv2_data = {
> +const struct vc4_pv_data bcm2711_pv2_data = {
>  	.base = {
>  		.name = "pixelvalve-2",
>  		.debugfs_name = "crtc2_regs",
> @@ -1205,7 +1205,7 @@ static const struct vc4_pv_data bcm2711_pv2_data = {
>  	},
>  };
>  
> -static const struct vc4_pv_data bcm2711_pv3_data = {
> +const struct vc4_pv_data bcm2711_pv3_data = {
>  	.base = {
>  		.name = "pixelvalve-3",
>  		.debugfs_name = "crtc3_regs",
> @@ -1219,7 +1219,7 @@ static const struct vc4_pv_data bcm2711_pv3_data = {
>  	},
>  };
>  
> -static const struct vc4_pv_data bcm2711_pv4_data = {
> +const struct vc4_pv_data bcm2711_pv4_data = {
>  	.base = {
>  		.name = "pixelvalve-4",
>  		.debugfs_name = "crtc4_regs",
> diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
> index 5990d8f8c363..3b0ae2c3e33c 100644
> --- a/drivers/gpu/drm/vc4/vc4_drv.c
> +++ b/drivers/gpu/drm/vc4/vc4_drv.c
> @@ -196,7 +196,7 @@ static const struct drm_ioctl_desc vc4_drm_ioctls[] = {
>  	DRM_IOCTL_DEF_DRV(VC4_PERFMON_GET_VALUES, vc4_perfmon_get_values_ioctl, DRM_RENDER_ALLOW),
>  };
>  
> -static const struct drm_driver vc4_drm_driver = {
> +const struct drm_driver vc4_drm_driver = {
>  	.driver_features = (DRIVER_MODESET |
>  			    DRIVER_ATOMIC |
>  			    DRIVER_GEM |
> @@ -225,7 +225,7 @@ static const struct drm_driver vc4_drm_driver = {
>  	.patchlevel = DRIVER_PATCHLEVEL,
>  };
>  
> -static const struct drm_driver vc5_drm_driver = {
> +const struct drm_driver vc5_drm_driver = {
>  	.driver_features = (DRIVER_MODESET |
>  			    DRIVER_ATOMIC |
>  			    DRIVER_GEM),
> diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
> index e0be7a81a24a..418f4f308e36 100644
> --- a/drivers/gpu/drm/vc4/vc4_drv.h
> +++ b/drivers/gpu/drm/vc4/vc4_drv.h
> @@ -24,6 +24,9 @@
>  struct drm_device;
>  struct drm_gem_object;
>  
> +extern const struct drm_driver vc4_drm_driver;
> +extern const struct drm_driver vc5_drm_driver;
> +
>  /* Don't forget to update vc4_bo.c: bo_type_names[] when adding to
>   * this.
>   */
> @@ -523,6 +526,8 @@ struct vc4_crtc_data {
>  	int hvs_output;
>  };
>  
> +extern const struct vc4_crtc_data vc4_txp_crtc_data;
> +
>  struct vc4_pv_data {
>  	struct vc4_crtc_data	base;
>  
> @@ -535,6 +540,15 @@ struct vc4_pv_data {
>  	enum vc4_encoder_type encoder_types[4];
>  };
>  
> +extern const struct vc4_pv_data bcm2835_pv0_data;
> +extern const struct vc4_pv_data bcm2835_pv1_data;
> +extern const struct vc4_pv_data bcm2835_pv2_data;
> +extern const struct vc4_pv_data bcm2711_pv0_data;
> +extern const struct vc4_pv_data bcm2711_pv1_data;
> +extern const struct vc4_pv_data bcm2711_pv2_data;
> +extern const struct vc4_pv_data bcm2711_pv3_data;
> +extern const struct vc4_pv_data bcm2711_pv4_data;
> +
>  struct vc4_crtc {
>  	struct drm_crtc base;
>  	struct platform_device *pdev;
> @@ -920,6 +934,8 @@ int vc4_page_flip(struct drm_crtc *crtc,
>  		  struct drm_pending_vblank_event *event,
>  		  uint32_t flags,
>  		  struct drm_modeset_acquire_ctx *ctx);
> +int vc4_crtc_atomic_check(struct drm_crtc *crtc,
> +			  struct drm_atomic_state *state);
>  struct drm_crtc_state *vc4_crtc_duplicate_state(struct drm_crtc *crtc);
>  void vc4_crtc_destroy_state(struct drm_crtc *crtc,
>  			    struct drm_crtc_state *state);
> diff --git a/drivers/gpu/drm/vc4/vc4_txp.c b/drivers/gpu/drm/vc4/vc4_txp.c
> index 4f7ce5d3e8ad..2b69454b8534 100644
> --- a/drivers/gpu/drm/vc4/vc4_txp.c
> +++ b/drivers/gpu/drm/vc4/vc4_txp.c
> @@ -479,7 +479,7 @@ static irqreturn_t vc4_txp_interrupt(int irq, void *data)
>  	return IRQ_HANDLED;
>  }
>  
> -static const struct vc4_crtc_data vc4_txp_crtc_data = {
> +const struct vc4_crtc_data vc4_txp_crtc_data = {
>  	.name = "txp",
>  	.debugfs_name = "txp_regs",
>  	.hvs_available_channels = BIT(2),
>