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/*
* Copyright (c) 2006-2008 Intel Corporation
* Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
* Copyright (c) 2008 Red Hat Inc.
* Copyright (c) 2016 Intel Corporation
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting documentation, and
* that the name of the copyright holders not be used in advertising or
* publicity pertaining to distribution of the software without specific,
* written prior permission. The copyright holders make no representations
* about the suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*/
#include <drm/drmP.h>
#include "drm_crtc_internal.h"
/**
* DOC: overview
*
* The KMS API doesn't standardize backing storage object creation and leaves it
* to driver-specific ioctls. Furthermore actually creating a buffer object even
* for GEM-based drivers is done through a driver-specific ioctl - GEM only has
* a common userspace interface for sharing and destroying objects. While not an
* issue for full-fledged graphics stacks that include device-specific userspace
* components (in libdrm for instance), this limit makes DRM-based early boot
* graphics unnecessarily complex.
*
* Dumb objects partly alleviate the problem by providing a standard API to
* create dumb buffers suitable for scanout, which can then be used to create
* KMS frame buffers.
*
* To support dumb objects drivers must implement the dumb_create,
* dumb_destroy and dumb_map_offset operations from &struct drm_driver. See
* there for further details.
*
* Note that dumb objects may not be used for gpu acceleration, as has been
* attempted on some ARM embedded platforms. Such drivers really must have
* a hardware-specific ioctl to allocate suitable buffer objects.
*/
int drm_mode_create_dumb_ioctl(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
struct drm_mode_create_dumb *args = data;
u32 cpp, stride, size;
if (!dev->driver->dumb_create)
return -ENOSYS;
if (!args->width || !args->height || !args->bpp)
return -EINVAL;
/* overflow checks for 32bit size calculations */
/* NOTE: DIV_ROUND_UP() can overflow */
cpp = DIV_ROUND_UP(args->bpp, 8);
if (!cpp || cpp > 0xffffffffU / args->width)
return -EINVAL;
stride = cpp * args->width;
if (args->height > 0xffffffffU / stride)
return -EINVAL;
/* test for wrap-around */
size = args->height * stride;
if (PAGE_ALIGN(size) == 0)
return -EINVAL;
/*
* handle, pitch and size are output parameters. Zero them out to
* prevent drivers from accidentally using uninitialized data. Since
* not all existing userspace is clearing these fields properly we
* cannot reject IOCTL with garbage in them.
*/
args->handle = 0;
args->pitch = 0;
args->size = 0;
return dev->driver->dumb_create(file_priv, dev, args);
}
/**
* drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer
* @dev: DRM device
* @data: ioctl data
* @file_priv: DRM file info
*
* Allocate an offset in the drm device node's address space to be able to
* memory map a dumb buffer.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
int drm_mode_mmap_dumb_ioctl(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
struct drm_mode_map_dumb *args = data;
/* call driver ioctl to get mmap offset */
if (!dev->driver->dumb_map_offset)
return -ENOSYS;
return dev->driver->dumb_map_offset(file_priv, dev, args->handle, &args->offset);
}
int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
struct drm_mode_destroy_dumb *args = data;
if (!dev->driver->dumb_destroy)
return -ENOSYS;
return dev->driver->dumb_destroy(file_priv, dev, args->handle);
}
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