drm: Add GEM backed framebuffer library (4c3dbb2c) · Commits · 戴 / test

Documentation/gpu/drm-kms-helpers.rst

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		@@ -296,3 +296,12 @@ Auxiliary Modeset Helpers

		.. kernel-doc:: drivers/gpu/drm/drm_modeset_helper.c
		:export:

		Framebuffer GEM Helper Reference
		================================

		.. kernel-doc:: drivers/gpu/drm/drm_gem_framebuffer_helper.c
		:doc: overview

		.. kernel-doc:: drivers/gpu/drm/drm_gem_framebuffer_helper.c
		:export:

drivers/gpu/drm/Makefile

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		@@ -33,7 +33,7 @@ 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_simple_kms_helper.o drm_modeset_helper.o \
		drm_scdc_helper.o
		drm_scdc_helper.o drm_gem_framebuffer_helper.o

		drm_kms_helper-$(CONFIG_DRM_PANEL_BRIDGE) += bridge/panel.o
		drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o

drivers/gpu/drm/drm_gem_framebuffer_helper.c

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		/*
		* drm gem framebuffer helper functions
		*
		* Copyright (C) 2017 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 <linux/dma-buf.h>
		#include <linux/dma-fence.h>
		#include <linux/reservation.h>
		#include <linux/slab.h>

		#include <drm/drmP.h>
		#include <drm/drm_atomic.h>
		#include <drm/drm_fb_helper.h>
		#include <drm/drm_fourcc.h>
		#include <drm/drm_framebuffer.h>
		#include <drm/drm_gem.h>
		#include <drm/drm_gem_framebuffer_helper.h>
		#include <drm/drm_modeset_helper.h>

		/**
		* DOC: overview
		*
		* This library provides helpers for drivers that don't subclass
		* &drm_framebuffer and and use &drm_gem_object for their backing storage.
		*
		* Drivers without additional needs to validate framebuffers can simply use
		* drm_gem_fb_create() and everything is wired up automatically. But all
		* parts can be used individually.
		*/

		/**
		* drm_gem_fb_get_obj() - Get GEM object for framebuffer
		* @fb: The framebuffer
		* @plane: Which plane
		*
		* Returns the GEM object for given framebuffer.
		*/
		struct drm_gem_object drm_gem_fb_get_obj(struct drm_framebuffer fb,
		unsigned int plane)
		{
		if (plane >= 4)
		return NULL;

		return fb->obj[plane];
		}
		EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);

		static struct drm_framebuffer *
		drm_gem_fb_alloc(struct drm_device *dev,
		const struct drm_mode_fb_cmd2 *mode_cmd,
		struct drm_gem_object **obj, unsigned int num_planes,
		const struct drm_framebuffer_funcs *funcs)
		{
		struct drm_framebuffer *fb;
		int ret, i;

		fb = kzalloc(sizeof(*fb), GFP_KERNEL);
		if (!fb)
		return ERR_PTR(-ENOMEM);

		drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);

		for (i = 0; i < num_planes; i++)
		fb->obj[i] = obj[i];

		ret = drm_framebuffer_init(dev, fb, funcs);
		if (ret) {
		DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n",
		ret);
		kfree(fb);
		return ERR_PTR(ret);
		}

		return fb;
		}

		/**
		* drm_gem_fb_destroy - Free GEM backed framebuffer
		* @fb: DRM framebuffer
		*
		* Frees a GEM backed framebuffer with its backing buffer(s) and the structure
		* itself. Drivers can use this as their &drm_framebuffer_funcs->destroy
		* callback.
		*/
		void drm_gem_fb_destroy(struct drm_framebuffer *fb)
		{
		int i;

		for (i = 0; i < 4; i++)
		drm_gem_object_put_unlocked(fb->obj[i]);

		drm_framebuffer_cleanup(fb);
		kfree(fb);
		}
		EXPORT_SYMBOL(drm_gem_fb_destroy);

		/**
		* drm_gem_fb_create_handle - Create handle for GEM backed framebuffer
		* @fb: DRM framebuffer
		* @file: drm file
		* @handle: handle created
		*
		* Drivers can use this as their &drm_framebuffer_funcs->create_handle
		* callback.
		*
		* Returns:
		* 0 on success or a negative error code on failure.
		*/
		int drm_gem_fb_create_handle(struct drm_framebuffer fb, struct drm_file file,
		unsigned int *handle)
		{
		return drm_gem_handle_create(file, fb->obj[0], handle);
		}
		EXPORT_SYMBOL(drm_gem_fb_create_handle);

		/**
		* drm_gem_fb_create_with_funcs() - helper function for the
		* &drm_mode_config_funcs.fb_create
		* callback
		* @dev: DRM device
		* @file: drm file for the ioctl call
		* @mode_cmd: metadata from the userspace fb creation request
		* @funcs: vtable to be used for the new framebuffer object
		*
		* This can be used to set &drm_framebuffer_funcs for drivers that need the
		* &drm_framebuffer_funcs.dirty callback. Use drm_gem_fb_create() if you don't
		* need to change &drm_framebuffer_funcs.
		* The function does buffer size validation.
		*/
		struct drm_framebuffer *
		drm_gem_fb_create_with_funcs(struct drm_device dev, struct drm_file file,
		const struct drm_mode_fb_cmd2 *mode_cmd,
		const struct drm_framebuffer_funcs *funcs)
		{
		const struct drm_format_info *info;
		struct drm_gem_object *objs[4];
		struct drm_framebuffer *fb;
		int ret, i;

		info = drm_get_format_info(dev, mode_cmd);
		if (!info)
		return ERR_PTR(-EINVAL);

		for (i = 0; i < info->num_planes; i++) {
		unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
		unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
		unsigned int min_size;

		objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
		if (!objs[i]) {
		DRM_DEV_ERROR(dev->dev, "Failed to lookup GEM\n");
		ret = -ENOENT;
		goto err_gem_object_put;
		}

		min_size = (height - 1) * mode_cmd->pitches[i]
		+ width * info->cpp[i]
		+ mode_cmd->offsets[i];

		if (objs[i]->size < min_size) {
		drm_gem_object_put_unlocked(objs[i]);
		ret = -EINVAL;
		goto err_gem_object_put;
		}
		}

		fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs);
		if (IS_ERR(fb)) {
		ret = PTR_ERR(fb);
		goto err_gem_object_put;
		}

		return fb;

		err_gem_object_put:
		for (i--; i >= 0; i--)
		drm_gem_object_put_unlocked(objs[i]);

		return ERR_PTR(ret);
		}
		EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);

		static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
		.destroy = drm_gem_fb_destroy,
		.create_handle = drm_gem_fb_create_handle,
		};

		/**
		* drm_gem_fb_create() - &drm_mode_config_funcs.fb_create callback function
		* @dev: DRM device
		* @file: drm file for the ioctl call
		* @mode_cmd: metadata from the userspace fb creation request
		*
		* If your hardware has special alignment or pitch requirements these should be
		* checked before calling this function. The function does buffer size
		* validation. Use drm_gem_fb_create_with_funcs() if you need to set
		* &drm_framebuffer_funcs.dirty.
		*/
		struct drm_framebuffer *
		drm_gem_fb_create(struct drm_device dev, struct drm_file file,
		const struct drm_mode_fb_cmd2 *mode_cmd)
		{
		return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
		&drm_gem_fb_funcs);
		}
		EXPORT_SYMBOL_GPL(drm_gem_fb_create);

		/**
		* drm_gem_fb_prepare_fb() - Prepare gem framebuffer
		* @plane: Which plane
		* @state: Plane state attach fence to
		*
		* This can be used as the &drm_plane_helper_funcs.prepare_fb hook.
		*
		* This function checks if the plane FB has an dma-buf attached, extracts
		* the exclusive fence and attaches it to plane state for the atomic helper
		* to wait on.
		*
		* 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.
		*/
		int drm_gem_fb_prepare_fb(struct drm_plane *plane,
		struct drm_plane_state *state)
		{
		struct dma_buf *dma_buf;
		struct dma_fence *fence;

		if ((plane->state->fb == state->fb) \|\| !state->fb)
		return 0;

		dma_buf = drm_gem_fb_get_obj(state->fb, 0)->dma_buf;
		if (dma_buf) {
		fence = reservation_object_get_excl_rcu(dma_buf->resv);
		drm_atomic_set_fence_for_plane(state, fence);
		}

		return 0;
		}
		EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);

		/**
		* drm_gem_fbdev_fb_create - Create a drm_framebuffer for fbdev emulation
		* @dev: DRM device
		* @sizes: fbdev size description
		* @pitch_align: optional pitch alignment
		* @obj: GEM object backing the framebuffer
		* @funcs: vtable to be used for the new framebuffer object
		*
		* This function creates a framebuffer for use with fbdev emulation.
		*
		* Returns:
		* Pointer to a drm_framebuffer on success or an error pointer on failure.
		*/
		struct drm_framebuffer *
		drm_gem_fbdev_fb_create(struct drm_device *dev,
		struct drm_fb_helper_surface_size *sizes,
		unsigned int pitch_align, struct drm_gem_object *obj,
		const struct drm_framebuffer_funcs *funcs)
		{
		struct drm_mode_fb_cmd2 mode_cmd = { 0 };

		mode_cmd.width = sizes->surface_width;
		mode_cmd.height = sizes->surface_height;
		mode_cmd.pitches[0] = sizes->surface_width *
		DIV_ROUND_UP(sizes->surface_bpp, 8);
		if (pitch_align)
		mode_cmd.pitches[0] = roundup(mode_cmd.pitches[0],
		pitch_align);
		mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
		sizes->surface_depth);
		if (obj->size < mode_cmd.pitches[0] * mode_cmd.height)
		return ERR_PTR(-EINVAL);

		return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs);
		}
		EXPORT_SYMBOL(drm_gem_fbdev_fb_create);

include/drm/drm_framebuffer.h

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		@@ -190,6 +190,13 @@ struct drm_framebuffer {
		* @filp_head: Placed on &drm_file.fbs, protected by &drm_file.fbs_lock.
		*/
		struct list_head filp_head;
		/**
		* @obj: GEM objects backing the framebuffer, one per plane (optional).
		*
		* This is used by the GEM framebuffer helpers, see e.g.
		* drm_gem_fb_create().
		*/
		struct drm_gem_object *obj[4];
		};

		#define obj_to_fb(x) container_of(x, struct drm_framebuffer, base)

include/drm/drm_gem_framebuffer_helper.h

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		#ifndef __DRM_GEM_FB_HELPER_H__
		#define __DRM_GEM_FB_HELPER_H__

		struct drm_device;
		struct drm_file;
		struct drm_fb_helper_surface_size;
		struct drm_framebuffer;
		struct drm_framebuffer_funcs;
		struct drm_gem_object;
		struct drm_mode_fb_cmd2;
		struct drm_plane;
		struct drm_plane_state;

		struct drm_gem_object drm_gem_fb_get_obj(struct drm_framebuffer fb,
		unsigned int plane);
		void drm_gem_fb_destroy(struct drm_framebuffer *fb);
		int drm_gem_fb_create_handle(struct drm_framebuffer fb, struct drm_file file,
		unsigned int *handle);

		struct drm_framebuffer *
		drm_gem_fb_create_with_funcs(struct drm_device dev, struct drm_file file,
		const struct drm_mode_fb_cmd2 *mode_cmd,
		const struct drm_framebuffer_funcs *funcs);
		struct drm_framebuffer *
		drm_gem_fb_create(struct drm_device dev, struct drm_file file,
		const struct drm_mode_fb_cmd2 *mode_cmd);

		int drm_gem_fb_prepare_fb(struct drm_plane *plane,
		struct drm_plane_state *state);

		struct drm_framebuffer *
		drm_gem_fbdev_fb_create(struct drm_device *dev,
		struct drm_fb_helper_surface_size *sizes,
		unsigned int pitch_align, struct drm_gem_object *obj,
		const struct drm_framebuffer_funcs *funcs);

		#endif

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