Re: [PATCH 3/4] drm: Add helper for simple display pipeline

On Thu, May 05, 2016 at 03:24:33PM +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

When resubmitting a patch please always have a per-patch changelog of what you've done. Otherwise you force reviewers to remember they looked at this already, dig out the old mail and compare ;-)

---

drivers/gpu/drm/Kconfig | 7 ++ drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/drm_simple_kms_helper.c | 157 ++++++++++++++++++++++++++++++++ include/drm/drm_simple_kms_helper.h | 88 ++++++++++++++++++

Please also add a new section (next to all the ones for the other kms helpers) in Documentation/DocBook/gpu.tmpl and pull your kerneldoc in. Please also add a short overview kernel doc section to the .c file (Using the DOC: header) and also pull that into the overall gpu docs.

You can check the results using

$ make htmldocs

4 files changed, 253 insertions(+) create mode 100644 drivers/gpu/drm/drm_simple_kms_helper.c create mode 100644 include/drm/drm_simple_kms_helper.h

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 16e4c21..ff9f480 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -39,6 +39,13 @@ config DRM_KMS_HELPER help CRTC helpers for KMS drivers.

+config DRM_SIMPLE_KMS_HELPER

• tristate
• depends on DRM
• select DRM_KMS_HELPER
• help

•  Helpers for very simple KMS drivers.
  

config DRM_KMS_FB_HELPER bool depends on DRM_KMS_HELPER diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 43c2abf..7e99923 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -31,6 +31,7 @@ drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o drm_kms_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o

obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o +obj-$(CONFIG_DRM_SIMPLE_KMS_HELPER) += drm_simple_kms_helper.o

CFLAGS_drm_trace_points.o := -I$(src)

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..c8725bb --- /dev/null +++ b/drivers/gpu/drm/drm_simple_kms_helper.c @@ -0,0 +1,157 @@ +/*

• • 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>

+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 *pstate)
  

+{

• struct drm_simple_display_pipe *pipe;
• struct drm_crtc_state *cstate;
• pipe = container_of(plane, struct drm_simple_display_pipe, plane);
• if (!pipe->funcs || !pipe->funcs->check)

• return 0;
  

• cstate = drm_atomic_get_existing_crtc_state(pstate->state,

• 				    &pipe->crtc);
  

• return pipe->funcs->check(pipe, pstate, cstate);

+}

+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
• • @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.

need to specify that @funcs is optional.

• • Returns:
• • Zero on success, error code on failure.

"_negative_ error code"

• */

+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);
• 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..69eac94 --- /dev/null +++ b/include/drm/drm_simple_kms_helper.h @@ -0,0 +1,88 @@ +/*

• • 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.
  

Please add boilerplate to all these hooks along the lines of:

"This hook is optional."

Besides that little bit of polish looks all good to me. -Daniel

• */
  

• 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.
  

• */
  

• 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.
  

• *
  

• * 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.
  

• */
  

• 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.
• */

+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);
  

+#endif /* __LINUX_DRM_SIMPLE_KMS_HELPER_H */

2.2.2