blob: 4d682a6e8bcbc6d780c6545dd282f9b69d103069 [file] [log] [blame]
/*
* 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 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. Other drivers
* can use all parts independently.
*/
/**
* drm_gem_fb_get_obj() - Get GEM object backing the framebuffer
* @fb: Framebuffer
* @plane: Plane index
*
* No additional reference is taken beyond the one that the &drm_frambuffer
* already holds.
*
* Returns:
* Pointer to &drm_gem_object for the given framebuffer and plane index or NULL
* if it does not exist.
*/
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: 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: Framebuffer
* @file: DRM file to register the handle for
* @handle: Pointer to return the created handle
*
* This function creates a handle for the GEM object backing the framebuffer.
* Drivers can use this as their &drm_framebuffer_funcs->create_handle
* callback. The GETFB IOCTL calls into this 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 that holds the GEM handle(s) backing the framebuffer
* @mode_cmd: Metadata from the userspace framebuffer 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.
*
* Returns:
* Pointer to a &drm_framebuffer on success or an error pointer on failure.
*/
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_DEBUG_KMS("Failed to lookup GEM object\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() - Helper function for the
* &drm_mode_config_funcs.fb_create callback
* @dev: DRM device
* @file: DRM file that holds the GEM handle(s) backing the framebuffer
* @mode_cmd: Metadata from the userspace framebuffer creation request
*
* This function creates a new framebuffer object described by
* &drm_mode_fb_cmd2. This description includes handles for the buffer(s)
* backing the framebuffer.
*
* 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.
*
* Drivers can use this as their &drm_mode_config_funcs.fb_create callback.
* The ADDFB2 IOCTL calls into this callback.
*
* Returns:
* Pointer to a &drm_framebuffer on success or an error pointer on failure.
*/
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 a GEM backed framebuffer
* @plane: Plane
* @state: Plane state the fence will be attached to
*
* This function prepares a GEM backed framebuffer for scanout by checking if
* the plane framebuffer has a DMA-BUF attached. If it does, it extracts the
* exclusive fence and attaches it to the plane state for the atomic helper to
* wait on. 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.
*/
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 GEM backed &drm_framebuffer for fbdev
* emulation
* @dev: DRM device
* @sizes: fbdev size description
* @pitch_align: Optional pitch alignment
* @obj: GEM object backing the framebuffer
* @funcs: Optional vtable to be used for the new framebuffer object when the
* dirty callback is needed.
*
* This function creates a framebuffer from a &drm_fb_helper_surface_size
* description for use in the &drm_fb_helper_funcs.fb_probe callback.
*
* 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);
if (!funcs)
funcs = &drm_gem_fb_funcs;
return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs);
}
EXPORT_SYMBOL(drm_gem_fbdev_fb_create);