drm: Add GEM backed framebuffer library

This library provides helpers for drivers that don't subclass
drm_framebuffer and are backed by drm_gem_object. The code is
taken from drm_fb_cma_helper.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/1502631125-13557-2-git-send-email-noralf@tronnes.org
This commit is contained in:
Noralf Trønnes 2017-08-13 15:31:44 +02:00
parent d956e1293b
commit 4c3dbb2c31
5 changed files with 337 additions and 1 deletions

View File

@ -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:

View File

@ -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

View File

@ -0,0 +1,283 @@
/*
* 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);

View File

@ -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)

View File

@ -0,0 +1,37 @@
#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