Re: [RFC v2 3/8] drm: Add helper for simple kms drivers

["Noralf Trønnes" <noralf@tronnes.org>]

Den 13.04.2016 13:05, skrev Daniel Vetter:
> On Fri, Apr 08, 2016 at 07:05:05PM +0200, Noralf Trønnes wrote:
>> Provides helper functions for drivers that have a simple display
>> pipeline. Plane, crtc and encoder are collapsed into one entity.
>>
>> Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

[...]

>> +static void drm_simple_kms_encoder_disable(struct drm_encoder *encoder)
>> +{
>> +}
>> +
>> +static void drm_simple_kms_encoder_enable(struct drm_encoder *encoder)
>> +{
>> +}
>> +
>> +static int drm_simple_kms_encoder_atomic_check(struct drm_encoder *encoder,
>> +					struct drm_crtc_state *crtc_state,
>> +					struct drm_connector_state *conn_state)
>> +{
>> +	return 0;
>> +}
> Above dummy functions shouldn't be necessary.

I could remove .atomic_check, but not .disable and .enable which gave me
NULL pointer errors. I need .enable or .commit, and .disable or .dpms.

Gist:

void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
                                               struct drm_atomic_state 
*old_state)
{
         for_each_connector_in_state(old_state, connector, 
old_conn_state, i) {
                 const struct drm_encoder_helper_funcs *funcs;

                 funcs = encoder->helper_private;

                 if (funcs->enable)
                         funcs->enable(encoder);
                 else
                         funcs->commit(encoder);

static void
disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
{
         for_each_connector_in_state(old_state, connector, 
old_conn_state, i) {
                 const struct drm_encoder_helper_funcs *funcs;

                 funcs = encoder->helper_private;

                 if (connector->state->crtc && funcs->prepare)
                         funcs->prepare(encoder);
                 else if (funcs->disable)
                         funcs->disable(encoder);
                 else
                         funcs->dpms(encoder, DRM_MODE_DPMS_OFF);

>
>> +
>> +static const struct drm_encoder_helper_funcs drm_simple_kms_encoder_helper_funcs = {
>> +	.disable = drm_simple_kms_encoder_disable,
>> +	.enable = drm_simple_kms_encoder_enable,
>> +	.atomic_check = drm_simple_kms_encoder_atomic_check,
>> +};
>> +
>> +static const struct drm_encoder_funcs drm_simple_kms_encoder_funcs = {
>> +	.destroy = drm_encoder_cleanup,
>> +};
>> +
>> +static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc)
>> +{
>> +	struct drm_simple_display_pipe *pipe;
>> +
>> +	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
>> +	if (!pipe->funcs || !pipe->funcs->enable)
>> +		return;
>> +
>> +	pipe->funcs->enable(pipe, crtc->state);
>> +}
>> +
>> +static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc)
>> +{
>> +	struct drm_simple_display_pipe *pipe;
>> +
>> +	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
>> +	if (!pipe->funcs || !pipe->funcs->disable)
>> +		return;
>> +
>> +	pipe->funcs->disable(pipe);
>> +}
>> +
>> +static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
>> +	.disable = drm_simple_kms_crtc_disable,
>> +	.enable = drm_simple_kms_crtc_enable,
>> +};
>> +
>> +static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
>> +	.reset = drm_atomic_helper_crtc_reset,
>> +	.destroy = drm_crtc_cleanup,
>> +	.set_config = drm_atomic_helper_set_config,
>> +	.page_flip = drm_atomic_helper_page_flip,
>> +	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
>> +	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
>> +};
>> +
>> +static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
>> +					struct drm_plane_state *old_state)
>> +{
>> +	struct drm_simple_display_pipe *pipe;
>> +
>> +	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
>> +	if (!pipe->funcs || !pipe->funcs->plane_update)
>> +		return;
>> +
>> +	pipe->funcs->plane_update(pipe, old_state);
>> +}
>> +
>> +static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
>> +	.atomic_update = drm_simple_kms_plane_atomic_update,
>> +};
>> +
>> +static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
>> +	.update_plane		= drm_atomic_helper_update_plane,
>> +	.disable_plane		= drm_atomic_helper_disable_plane,
>> +	.destroy		= drm_plane_cleanup,
>> +	.reset			= drm_atomic_helper_plane_reset,
>> +	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
>> +	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
>> +};
>> +
>> +/**
>> + * drm_simple_display_pipe_init - Initialize a simple display pipe
>> + * @dev: DRM device
>> + * @pipe: simple display pipe object to initialize
>> + * @funcs: callbacks for the display pipe
>> + * @formats: array of supported formats (%DRM_FORMAT_*)
>> + * @format_count: number of elements in @formats
>> + * @connector: connector to attach and register
>> + *
>> + * Sets up a display pipe which consist of a really simple plane-crtc-encoder
>> + * pipe coupled with the provided connector.
>> + *
>> + * Returns:
>> + * Zero on success, error code on failure.
>> + */
>> +int drm_simple_display_pipe_init(struct drm_device *dev,
>> +				 struct drm_simple_display_pipe *pipe,
>> +				 struct drm_simple_display_pipe_funcs *funcs,
>> +				 const uint32_t *formats, unsigned int format_count,
>> +				 struct drm_connector *connector)
>> +{
>> +	struct drm_encoder *encoder = &pipe->encoder;
>> +	struct drm_plane *plane = &pipe->plane;
>> +	struct drm_crtc *crtc = &pipe->crtc;
>> +	int ret;
>> +
>> +	pipe->funcs = funcs;
>> +
>> +	drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
>> +	ret = drm_universal_plane_init(dev, plane, 0, &drm_simple_kms_plane_funcs,
>> +				       formats, format_count,
>> +				       DRM_PLANE_TYPE_PRIMARY, NULL);
>> +	if (ret)
>> +		return ret;
>> +
>> +	drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
>> +	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
>> +					&drm_simple_kms_crtc_funcs, NULL);
>> +	if (ret)
>> +		return ret;
>> +
>> +	encoder->possible_crtcs = 1 << drm_crtc_index(crtc);
>> +	drm_encoder_helper_add(encoder, &drm_simple_kms_encoder_helper_funcs);
>> +	ret = drm_encoder_init(dev, encoder, &drm_simple_kms_encoder_funcs,
>> +			       DRM_MODE_ENCODER_NONE, NULL);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = drm_mode_connector_attach_encoder(connector, encoder);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return drm_connector_register(connector);
>> +}
>> +EXPORT_SYMBOL(drm_simple_display_pipe_init);
>> +
>> +MODULE_LICENSE("GPL");
>> diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
>> new file mode 100644
>> index 0000000..0f7461b
>> --- /dev/null
>> +++ b/include/drm/drm_simple_kms_helper.h
>> @@ -0,0 +1,44 @@
>> +/*
>> + * Copyright (C) 2016 Noralf Trønnes
>> + *
>> + * 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 __LINUX_DRM_SIMPLE_KMS_HELPER_H
>> +#define __LINUX_DRM_SIMPLE_KMS_HELPER_H
>> +
>> +struct drm_simple_display_pipe;
>> +
>> +struct drm_simple_display_pipe_funcs {
>> +	void (*enable)(struct drm_simple_display_pipe *pipe,
>> +		       struct drm_crtc_state *crtc_state);
>> +	void (*disable)(struct drm_simple_display_pipe *pipe);
>> +	void (*plane_update)(struct drm_simple_display_pipe *pipe,
>> +			     struct drm_plane_state *plane_state);
> On 2nd thought maybe we want an atomic_check in here too, with same
> parameters *pipe, *crtc_state and *plane_state (so that it's useful for
> both plane-only updates and modeset changes).

I could do this for the plane:

struct drm_simple_display_pipe_funcs {
      void (*plane_check)(struct drm_simple_display_pipe *pipe,
                          struct drm_plane_state *plane_state);
}

static void drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
                                         struct drm_plane_state *state)
{
         struct drm_simple_display_pipe *pipe;

         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
         if (!pipe->funcs || !pipe->funcs->plane_check)
                 return;

         pipe->funcs->plane_check(pipe, state);
}

static const struct drm_plane_helper_funcs 
drm_simple_kms_plane_helper_funcs = {
         .atomic_check = drm_simple_kms_plane_atomic_check,
};

But how should I do crtc_state ?

Noralf.

>> +};
>> +
>> +struct drm_simple_display_pipe {
>> +	struct drm_crtc crtc;
>> +	struct drm_plane plane;
>> +	struct drm_encoder encoder;
>> +	struct drm_connector *connector;
>> +
>> +	struct drm_simple_display_pipe_funcs *funcs;
>> +};
>> +
>> +int drm_simple_display_pipe_init(struct drm_device *dev,
>> +				 struct drm_simple_display_pipe *pipe,
>> +				 struct drm_simple_display_pipe_funcs *funcs,
>> +				 const uint32_t *formats, unsigned int format_count,
>> +				 struct drm_connector *connector);
>> +struct drm_connector *
>> +drm_simple_kms_panel_connector_create(struct drm_device *dev,
>> +				      struct drm_panel *panel,
>> +				      int connector_type);
>> +
>> +
>> +
>> +#endif /* __LINUX_DRM_SIMPLE_KMS_HELPER_H */
>> -- 
>> 2.2.2
>>
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