diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dumb_buffers.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dumb_buffers.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_dumb_buffers.c b/drivers/gpu/drm/drm_dumb_buffers.c new file mode 100644 index 000000000000..8ac5a1c1d811 --- /dev/null +++ b/drivers/gpu/drm/drm_dumb_buffers.c @@ -0,0 +1,128 @@ +/* + * 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); +} + |