Commit 820c1707 authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

drm/gem: Move drm_gem_fb_prepare_fb() to GEM atomic helpers 



The function drm_gem_fb_prepare_fb() is a helper for atomic modesetting,
but currently located next to framebuffer helpers. Move it to GEM atomic
helpers, rename it slightly and adopt the drivers. Same for the rsp
simple-pipe helper.

Compile-tested with x86-64, aarch64 and arm. The patch is fairly large,
but there are no functional changes.

v3:
	* remove out-comented line in drm_gem_framebuffer_helper.h
	  (Maxime)
v2:
	* rename to drm_gem_plane_helper_prepare_fb() (Daniel)
	* add tutorial-style documentation

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Acked-by: default avatarMaxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210222141756.7864-1-tzimmermann@suse.de
parent dc739820

drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c

+2 −2
Original line number Diff line number Diff line
@@ -9,8 +9,8 @@ 
#include <drm/drm_device.h>

#include <drm/drm_fb_cma_helper.h>

#include <drm/drm_fourcc.h>

#include <drm/drm_gem_atomic_helper.h>

#include <drm/drm_gem_cma_helper.h>

#include <drm/drm_gem_framebuffer_helper.h>

#include <drm/drm_panel.h>

#include <drm/drm_simple_kms_helper.h>

#include <drm/drm_vblank.h>
@@ -220,7 +220,7 @@ static const struct drm_simple_display_pipe_funcs aspeed_gfx_funcs = { 
	.enable		= aspeed_gfx_pipe_enable,

	.disable	= aspeed_gfx_pipe_disable,

	.update		= aspeed_gfx_pipe_update,

	.prepare_fb	= drm_gem_fb_simple_display_pipe_prepare_fb,

	.prepare_fb	= drm_gem_simple_display_pipe_prepare_fb,

	.enable_vblank	= aspeed_gfx_enable_vblank,

	.disable_vblank	= aspeed_gfx_disable_vblank,

};

drivers/gpu/drm/drm_gem_atomic_helper.c

+92 −4
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later



#include <linux/dma-resv.h>



#include <drm/drm_atomic_state_helper.h>

#include <drm/drm_atomic_uapi.h>

#include <drm/drm_gem.h>

#include <drm/drm_gem_atomic_helper.h>

#include <drm/drm_gem_framebuffer_helper.h>

#include <drm/drm_simple_kms_helper.h>
@@ -12,8 +16,33 @@ 
 *

 * The GEM atomic helpers library implements generic atomic-commit

 * functions for drivers that use GEM objects. Currently, it provides

 * plane state and framebuffer BO mappings for planes with shadow

 * buffers.

 * synchronization helpers, and plane state and framebuffer BO mappings

 * for planes with shadow buffers.

 *

 * Before scanout, a plane's framebuffer needs to be synchronized with

 * possible writers that draw into the framebuffer. All drivers should

 * call drm_gem_plane_helper_prepare_fb() from their implementation of

 * struct &drm_plane_helper.prepare_fb . It sets the plane's fence from

 * the framebuffer so that the DRM core can synchronize access automatically.

 *

 * drm_gem_plane_helper_prepare_fb() can also be used directly as

 * implementation of prepare_fb. For drivers based on

 * struct drm_simple_display_pipe, drm_gem_simple_display_pipe_prepare_fb()

 * provides equivalent functionality.

 *

 * .. code-block:: c

 *

 *	#include <drm/drm_gem_atomic_helper.h>

 *

 *	struct drm_plane_helper_funcs driver_plane_helper_funcs = {

 *		...,

 *		. prepare_fb = drm_gem_plane_helper_prepare_fb,

 *	};

 *

 *	struct drm_simple_display_pipe_funcs driver_pipe_funcs = {

 *		...,

 *		. prepare_fb = drm_gem_simple_display_pipe_prepare_fb,

 *	};

 *

 * A driver using a shadow buffer copies the content of the shadow buffers

 * into the HW's framebuffer memory during an atomic update. This requires
@@ -32,7 +61,7 @@ 
 *

 * .. code-block:: c

 *

 *	#include <drm/drm/gem_atomic_helper.h>

 *	#include <drm/drm_gem_atomic_helper.h>

 *

 *	struct drm_plane_funcs driver_plane_funcs = {

 *		...,
@@ -87,6 +116,65 @@ 
 *	}

 */



/*

 * Plane Helpers

 */



/**

 * drm_gem_plane_helper_prepare_fb() - Prepare a GEM backed framebuffer

 * @plane: Plane

 * @state: Plane state the fence will be attached to

 *

 * This function extracts the exclusive fence from &drm_gem_object.resv and

 * attaches it to plane state for the atomic helper to wait on. This is

 * necessary to correctly implement implicit synchronization for any buffers

 * shared as a struct &dma_buf. This function can be used as the

 * &drm_plane_helper_funcs.prepare_fb callback.

 *

 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple

 * GEM based framebuffer drivers which have their buffers always pinned in

 * memory.

 *

 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and

 * explicit fencing in atomic modeset updates.

 */

int drm_gem_plane_helper_prepare_fb(struct drm_plane *plane, struct drm_plane_state *state)

{

	struct drm_gem_object *obj;

	struct dma_fence *fence;



	if (!state->fb)

		return 0;



	obj = drm_gem_fb_get_obj(state->fb, 0);

	fence = dma_resv_get_excl_rcu(obj->resv);

	drm_atomic_set_fence_for_plane(state, fence);



	return 0;

}

EXPORT_SYMBOL_GPL(drm_gem_plane_helper_prepare_fb);



/**

 * drm_gem_simple_display_pipe_prepare_fb - prepare_fb helper for &drm_simple_display_pipe

 * @pipe: Simple display pipe

 * @plane_state: Plane state

 *

 * This function uses drm_gem_plane_helper_prepare_fb() to extract the exclusive fence

 * from &drm_gem_object.resv and attaches it to plane state for the atomic

 * helper to wait on. This is necessary to correctly implement implicit

 * synchronization for any buffers shared as a struct &dma_buf. Drivers can use

 * this as their &drm_simple_display_pipe_funcs.prepare_fb callback.

 *

 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and

 * explicit fencing in atomic modeset updates.

 */

int drm_gem_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe,

					   struct drm_plane_state *plane_state)

{

	return drm_gem_plane_helper_prepare_fb(&pipe->plane, plane_state);

}

EXPORT_SYMBOL(drm_gem_simple_display_pipe_prepare_fb);



/*

 * Shadow-buffered Planes

 */
@@ -198,7 +286,7 @@ int drm_gem_prepare_shadow_fb(struct drm_plane *plane, struct drm_plane_state *p 
	if (!fb)

		return 0;



	ret = drm_gem_fb_prepare_fb(plane, plane_state);

	ret = drm_gem_plane_helper_prepare_fb(plane, plane_state);

	if (ret)

		return ret;

drivers/gpu/drm/drm_gem_framebuffer_helper.c

+0 −63
Original line number Diff line number Diff line
@@ -5,13 +5,8 @@ 
 * Copyright (C) 2017 Noralf Trønnes

 */



#include <linux/dma-buf.h>

#include <linux/dma-fence.h>

#include <linux/dma-resv.h>

#include <linux/slab.h>



#include <drm/drm_atomic.h>

#include <drm/drm_atomic_uapi.h>

#include <drm/drm_damage_helper.h>

#include <drm/drm_fb_helper.h>

#include <drm/drm_fourcc.h>
@@ -19,7 +14,6 @@ 
#include <drm/drm_gem.h>

#include <drm/drm_gem_framebuffer_helper.h>

#include <drm/drm_modeset_helper.h>

#include <drm/drm_simple_kms_helper.h>



#define AFBC_HEADER_SIZE		16

#define AFBC_TH_LAYOUT_ALIGNMENT	8
@@ -432,60 +426,3 @@ int drm_gem_fb_afbc_init(struct drm_device *dev, 
	return 0;

}

EXPORT_SYMBOL_GPL(drm_gem_fb_afbc_init);
 


/**

 * drm_gem_fb_prepare_fb() - Prepare a GEM backed framebuffer

 * @plane: Plane

 * @state: Plane state the fence will be attached to

 *

 * This function extracts the exclusive fence from &drm_gem_object.resv and

 * attaches it to plane state for the atomic helper to wait on. This is

 * necessary to correctly implement implicit synchronization for any buffers

 * shared as a struct &dma_buf. This function can be used as the

 * &drm_plane_helper_funcs.prepare_fb callback.

 *

 * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple

 * gem based framebuffer drivers which have their buffers always pinned in

 * memory.

 *

 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and

 * explicit fencing in atomic modeset updates.

 */

int drm_gem_fb_prepare_fb(struct drm_plane *plane,

			  struct drm_plane_state *state)

{

	struct drm_gem_object *obj;

	struct dma_fence *fence;



	if (!state->fb)

		return 0;



	obj = drm_gem_fb_get_obj(state->fb, 0);

	fence = dma_resv_get_excl_rcu(obj->resv);

	drm_atomic_set_fence_for_plane(state, fence);



	return 0;

}

EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);



/**

 * drm_gem_fb_simple_display_pipe_prepare_fb - prepare_fb helper for

 *     &drm_simple_display_pipe

 * @pipe: Simple display pipe

 * @plane_state: Plane state

 *

 * This function uses drm_gem_fb_prepare_fb() to extract the exclusive fence

 * from &drm_gem_object.resv and attaches it to plane state for the atomic

 * helper to wait on. This is necessary to correctly implement implicit

 * synchronization for any buffers shared as a struct &dma_buf. Drivers can use

 * this as their &drm_simple_display_pipe_funcs.prepare_fb callback.

 *

 * See drm_atomic_set_fence_for_plane() for a discussion of implicit and

 * explicit fencing in atomic modeset updates.

 */

int drm_gem_fb_simple_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe,

					      struct drm_plane_state *plane_state)

{

	return drm_gem_fb_prepare_fb(&pipe->plane, plane_state);

}

EXPORT_SYMBOL(drm_gem_fb_simple_display_pipe_prepare_fb);

drivers/gpu/drm/drm_gem_vram_helper.c

+2 −2
Original line number Diff line number Diff line
@@ -8,7 +8,7 @@ 
#include <drm/drm_drv.h>

#include <drm/drm_file.h>

#include <drm/drm_framebuffer.h>

#include <drm/drm_gem_framebuffer_helper.h>

#include <drm/drm_gem_atomic_helper.h>

#include <drm/drm_gem_ttm_helper.h>

#include <drm/drm_gem_vram_helper.h>

#include <drm/drm_managed.h>
@@ -700,7 +700,7 @@ drm_gem_vram_plane_helper_prepare_fb(struct drm_plane *plane, 
			goto err_drm_gem_vram_unpin;

	}



	ret = drm_gem_fb_prepare_fb(plane, new_state);

	ret = drm_gem_plane_helper_prepare_fb(plane, new_state);

	if (ret)

		goto err_drm_gem_vram_unpin;

drivers/gpu/drm/imx/dcss/dcss-plane.c

+2 −2
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ 
#include <drm/drm_atomic.h>

#include <drm/drm_atomic_helper.h>

#include <drm/drm_fb_cma_helper.h>

#include <drm/drm_gem_framebuffer_helper.h>

#include <drm/drm_gem_atomic_helper.h>

#include <drm/drm_gem_cma_helper.h>



#include "dcss-dev.h"
@@ -355,7 +355,7 @@ static void dcss_plane_atomic_disable(struct drm_plane *plane, 
}



static const struct drm_plane_helper_funcs dcss_plane_helper_funcs = {

	.prepare_fb = drm_gem_fb_prepare_fb,

	.prepare_fb = drm_gem_plane_helper_prepare_fb,

	.atomic_check = dcss_plane_atomic_check,

	.atomic_update = dcss_plane_atomic_update,

	.atomic_disable = dcss_plane_atomic_disable,