Re: [PATCH v4 3/3] drm: Add helper for simple display pipeline

On Sun, May 29, 2016 at 05:38:39PM +0200, Noralf Trønnes wrote:

Den 12.05.2016 20:25, skrev Noralf Trønnes:

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Provides helper functions for drivers that have a simple display pipeline. Plane, crtc and encoder are collapsed into one entity.

Cc: jsarha@ti.com Signed-off-by: Noralf Trønnes noralf@tronnes.org

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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..d45417a --- /dev/null +++ b/drivers/gpu/drm/drm_simple_kms_helper.c @@ -0,0 +1,208 @@ +/*

• • 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->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);

I'm wondering if we shouldn't remove drm_connector_register() here, because it doesn't fit the pattern I've seen in the latest drivers:

    drm = drm_dev_alloc(...);

    /* init */

    ret = drm_dev_register(drm, 0);
    ret = drm_connector_register_all(drm);

Excellent point, this should indeed be removed. drm_simple_display_pipe_init should just wire up the connector to the pipeline, not init/register it at all imo. -Daniel