[PATCH v5] drm: Add helper for simple display pipeline
Daniel Vetter
daniel at ffwll.ch
Fri Jun 10 15:34:58 UTC 2016
On Fri, Jun 10, 2016 at 04:55:59PM +0200, Noralf Trønnes wrote:
> Provides helper functions for drivers that have a simple display
> pipeline. Plane, crtc and encoder are collapsed into one entity.
>
> Cc: jsarha at ti.com
> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
> ---
>
> Changes since v4:
> - Remove drm_connector_register() call
> - Forgot to assign pipe->connector
>
> Changes since v3:
> - (struct drm_simple_display_pipe *)->funcs should be const
>
> Changes since v2:
> - Drop Kconfig knob DRM_KMS_HELPER
> - Expand documentation
>
> Changes since v1:
> - Add DOC header and add to gpu.tmpl
> - Fix docs: @funcs is optional, "negative error code",
> "This hook is optional."
> - Add checks to drm_simple_kms_plane_atomic_check()
Really nice work, and there's already 2-3 drivers in-flight that could
benefit from this. I think there's some room for polish and small
extensions, but much better when we do those once we have a few examples.
Applied to drm-misc, thanks.
-Daniel
>
> Documentation/DocBook/gpu.tmpl | 6 +
> drivers/gpu/drm/Makefile | 3 +-
> drivers/gpu/drm/drm_simple_kms_helper.c | 205 ++++++++++++++++++++++++++++++++
> include/drm/drm_simple_kms_helper.h | 94 +++++++++++++++
> 4 files changed, 307 insertions(+), 1 deletion(-)
> create mode 100644 drivers/gpu/drm/drm_simple_kms_helper.c
> create mode 100644 include/drm/drm_simple_kms_helper.h
>
> diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl
> index dac18b4..958d83c 100644
> --- a/Documentation/DocBook/gpu.tmpl
> +++ b/Documentation/DocBook/gpu.tmpl
> @@ -1683,6 +1683,12 @@ void intel_crt_init(struct drm_device *dev)
> !Edrivers/gpu/drm/drm_panel.c
> !Pdrivers/gpu/drm/drm_panel.c drm panel
> </sect2>
> + <sect2>
> + <title>Simple KMS Helper Reference</title>
> +!Iinclude/drm/drm_simple_kms_helper.h
> +!Edrivers/gpu/drm/drm_simple_kms_helper.c
> +!Pdrivers/gpu/drm/drm_simple_kms_helper.c overview
> + </sect2>
> </sect1>
>
> <!-- Internals: kms properties -->
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index be43afb..9390df8 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -23,7 +23,8 @@ drm-$(CONFIG_AGP) += drm_agpsupport.o
>
> drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
> drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
> - drm_kms_helper_common.o drm_dp_dual_mode_helper.o
> + drm_kms_helper_common.o drm_dp_dual_mode_helper.o \
> + drm_simple_kms_helper.o
>
> drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
> drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o
> diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c
> new file mode 100644
> index 0000000..b2071d4
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_simple_kms_helper.c
> @@ -0,0 +1,205 @@
> +/*
> + * 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.
> + */
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_atomic.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_plane_helper.h>
> +#include <drm/drm_simple_kms_helper.h>
> +#include <linux/slab.h>
> +
> +/**
> + * DOC: overview
> + *
> + * This helper library provides helpers for drivers for simple display
> + * hardware.
> + *
> + * drm_simple_display_pipe_init() initializes a simple display pipeline
> + * which has only one full-screen scanout buffer feeding one output. The
> + * pipeline is represented by struct &drm_simple_display_pipe and binds
> + * together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
> + * entity. Some flexibility for code reuse is provided through a separately
> + * allocated &drm_connector object and supporting optional &drm_bridge
> + * encoder drivers.
> + */
> +
> +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 int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
> + struct drm_plane_state *plane_state)
> +{
> + struct drm_rect src = {
> + .x1 = plane_state->src_x,
> + .y1 = plane_state->src_y,
> + .x2 = plane_state->src_x + plane_state->src_w,
> + .y2 = plane_state->src_y + plane_state->src_h,
> + };
> + struct drm_rect dest = {
> + .x1 = plane_state->crtc_x,
> + .y1 = plane_state->crtc_y,
> + .x2 = plane_state->crtc_x + plane_state->crtc_w,
> + .y2 = plane_state->crtc_y + plane_state->crtc_h,
> + };
> + struct drm_rect clip = { 0 };
> + struct drm_simple_display_pipe *pipe;
> + struct drm_crtc_state *crtc_state;
> + bool visible;
> + int ret;
> +
> + pipe = container_of(plane, struct drm_simple_display_pipe, plane);
> + crtc_state = drm_atomic_get_existing_crtc_state(plane_state->state,
> + &pipe->crtc);
> + if (crtc_state->enable != !!plane_state->crtc)
> + return -EINVAL; /* plane must match crtc enable state */
> +
> + if (!crtc_state->enable)
> + return 0; /* nothing to check when disabling or disabled */
> +
> + clip.x2 = crtc_state->adjusted_mode.hdisplay;
> + clip.y2 = crtc_state->adjusted_mode.vdisplay;
> + ret = drm_plane_helper_check_update(plane, &pipe->crtc,
> + plane_state->fb,
> + &src, &dest, &clip,
> + DRM_PLANE_HELPER_NO_SCALING,
> + DRM_PLANE_HELPER_NO_SCALING,
> + false, true, &visible);
> + if (ret)
> + return ret;
> +
> + if (!visible)
> + return -EINVAL;
> +
> + if (!pipe->funcs || !pipe->funcs->check)
> + return 0;
> +
> + return pipe->funcs->check(pipe, plane_state, crtc_state);
> +}
> +
> +static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
> + struct drm_plane_state *pstate)
> +{
> + struct drm_simple_display_pipe *pipe;
> +
> + pipe = container_of(plane, struct drm_simple_display_pipe, plane);
> + if (!pipe->funcs || !pipe->funcs->update)
> + return;
> +
> + pipe->funcs->update(pipe, pstate);
> +}
> +
> +static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
> + .atomic_check = drm_simple_kms_plane_atomic_check,
> + .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 pipeline
> + * @dev: DRM device
> + * @pipe: simple display pipe object to initialize
> + * @funcs: callbacks for the display pipe (optional)
> + * @formats: array of supported formats (%DRM_FORMAT_*)
> + * @format_count: number of elements in @formats
> + * @connector: connector to attach and register
> + *
> + * Sets up a display pipeline which consist of a really simple
> + * plane-crtc-encoder pipe coupled with the provided connector.
> + * Teardown of a simple display pipe is all handled automatically by the drm
> + * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
> + * release the memory for the structure themselves.
> + *
> + * Returns:
> + * Zero on success, negative error code on failure.
> + */
> +int drm_simple_display_pipe_init(struct drm_device *dev,
> + struct drm_simple_display_pipe *pipe,
> + const 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->connector = connector;
> + 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);
> + ret = drm_encoder_init(dev, encoder, &drm_simple_kms_encoder_funcs,
> + DRM_MODE_ENCODER_NONE, NULL);
> + if (ret)
> + return ret;
> +
> + return drm_mode_connector_attach_encoder(connector, encoder);
> +}
> +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..2690397
> --- /dev/null
> +++ b/include/drm/drm_simple_kms_helper.h
> @@ -0,0 +1,94 @@
> +/*
> + * 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 - helper operations for a simple
> + * display pipeline
> + */
> +struct drm_simple_display_pipe_funcs {
> + /**
> + * @enable:
> + *
> + * This function should be used to enable the pipeline.
> + * It is called when the underlying crtc is enabled.
> + * This hook is optional.
> + */
> + void (*enable)(struct drm_simple_display_pipe *pipe,
> + struct drm_crtc_state *crtc_state);
> + /**
> + * @disable:
> + *
> + * This function should be used to disable the pipeline.
> + * It is called when the underlying crtc is disabled.
> + * This hook is optional.
> + */
> + void (*disable)(struct drm_simple_display_pipe *pipe);
> +
> + /**
> + * @check:
> + *
> + * This function is called in the check phase of an atomic update,
> + * specifically when the underlying plane is checked.
> + * The simple display pipeline helpers already check that the plane is
> + * not scaled, fills the entire visible area and is always enabled
> + * when the crtc is also enabled.
> + * This hook is optional.
> + *
> + * RETURNS:
> + *
> + * 0 on success, -EINVAL if the state or the transition can't be
> + * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
> + * attempt to obtain another state object ran into a &drm_modeset_lock
> + * deadlock.
> + */
> + int (*check)(struct drm_simple_display_pipe *pipe,
> + struct drm_plane_state *plane_state,
> + struct drm_crtc_state *crtc_state);
> + /**
> + * @update:
> + *
> + * This function is called when the underlying plane state is updated.
> + * This hook is optional.
> + */
> + void (*update)(struct drm_simple_display_pipe *pipe,
> + struct drm_plane_state *plane_state);
> +};
> +
> +/**
> + * struct drm_simple_display_pipe - simple display pipeline
> + * @crtc: CRTC control structure
> + * @plane: Plane control structure
> + * @encoder: Encoder control structure
> + * @connector: Connector control structure
> + * @funcs: Pipeline control functions (optional)
> + *
> + * Simple display pipeline with plane, crtc and encoder collapsed into one
> + * entity. It should be initialized by calling drm_simple_display_pipe_init().
> + */
> +struct drm_simple_display_pipe {
> + struct drm_crtc crtc;
> + struct drm_plane plane;
> + struct drm_encoder encoder;
> + struct drm_connector *connector;
> +
> + const struct drm_simple_display_pipe_funcs *funcs;
> +};
> +
> +int drm_simple_display_pipe_init(struct drm_device *dev,
> + struct drm_simple_display_pipe *pipe,
> + const struct drm_simple_display_pipe_funcs *funcs,
> + const uint32_t *formats, unsigned int format_count,
> + struct drm_connector *connector);
> +
> +#endif /* __LINUX_DRM_SIMPLE_KMS_HELPER_H */
> --
> 2.8.2
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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