1/*
  2 * Copyright (c) 2006-2008 Intel Corporation
  3 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
  4 * Copyright (c) 2008 Red Hat Inc.
  5 * Copyright (c) 2016 Intel Corporation
  6 *
  7 * Permission to use, copy, modify, distribute, and sell this software and its
  8 * documentation for any purpose is hereby granted without fee, provided that
  9 * the above copyright notice appear in all copies and that both that copyright
 10 * notice and this permission notice appear in supporting documentation, and
 11 * that the name of the copyright holders not be used in advertising or
 12 * publicity pertaining to distribution of the software without specific,
 13 * written prior permission.  The copyright holders make no representations
 14 * about the suitability of this software for any purpose.  It is provided "as
 15 * is" without express or implied warranty.
 16 *
 17 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 18 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 19 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 20 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 21 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 22 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 23 * OF THIS SOFTWARE.
 24 */
 25
 26#include <drm/drm_device.h>
 27#include <drm/drm_drv.h>
 28#include <drm/drm_gem.h>
 29#include <drm/drm_mode.h>
 30
 31#include "drm_crtc_internal.h"
 32#include "drm_internal.h"
 33
 34/**
 35 * DOC: overview
 36 *
 37 * The KMS API doesn't standardize backing storage object creation and leaves it
 38 * to driver-specific ioctls. Furthermore actually creating a buffer object even
 39 * for GEM-based drivers is done through a driver-specific ioctl - GEM only has
 40 * a common userspace interface for sharing and destroying objects. While not an
 41 * issue for full-fledged graphics stacks that include device-specific userspace
 42 * components (in libdrm for instance), this limit makes DRM-based early boot
 43 * graphics unnecessarily complex.
 44 *
 45 * Dumb objects partly alleviate the problem by providing a standard API to
 46 * create dumb buffers suitable for scanout, which can then be used to create
 47 * KMS frame buffers.
 48 *
 49 * To support dumb objects drivers must implement the &drm_driver.dumb_create
 50 * and &drm_driver.dumb_map_offset operations (the latter defaults to
 51 * drm_gem_dumb_map_offset() if not set). Drivers that don't use GEM handles
 52 * additionally need to implement the &drm_driver.dumb_destroy operation. See
 53 * the callbacks for further details.
 54 *
 55 * Note that dumb objects may not be used for gpu acceleration, as has been
 56 * attempted on some ARM embedded platforms. Such drivers really must have
 57 * a hardware-specific ioctl to allocate suitable buffer objects.
 58 */
 59
 60int drm_mode_create_dumb(struct drm_device *dev,
 61			 struct drm_mode_create_dumb *args,
 62			 struct drm_file *file_priv)
 63{
 64	u32 cpp, stride, size;
 65
 66	if (!dev->driver->dumb_create)
 67		return -ENOSYS;
 68	if (!args->width || !args->height || !args->bpp)
 69		return -EINVAL;
 70
 71	/* overflow checks for 32bit size calculations */
 72	if (args->bpp > U32_MAX - 8)
 73		return -EINVAL;
 74	cpp = DIV_ROUND_UP(args->bpp, 8);
 75	if (cpp > U32_MAX / args->width)
 76		return -EINVAL;
 77	stride = cpp * args->width;
 78	if (args->height > U32_MAX / stride)
 79		return -EINVAL;
 80
 81	/* test for wrap-around */
 82	size = args->height * stride;
 83	if (PAGE_ALIGN(size) == 0)
 84		return -EINVAL;
 85
 86	/*
 87	 * handle, pitch and size are output parameters. Zero them out to
 88	 * prevent drivers from accidentally using uninitialized data. Since
 89	 * not all existing userspace is clearing these fields properly we
 90	 * cannot reject IOCTL with garbage in them.
 91	 */
 92	args->handle = 0;
 93	args->pitch = 0;
 94	args->size = 0;
 95
 96	return dev->driver->dumb_create(file_priv, dev, args);
 97}
 98
 99int drm_mode_create_dumb_ioctl(struct drm_device *dev,
100			       void *data, struct drm_file *file_priv)
101{
102	return drm_mode_create_dumb(dev, data, file_priv);
103}
104
105/**
106 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer
107 * @dev: DRM device
108 * @data: ioctl data
109 * @file_priv: DRM file info
110 *
111 * Allocate an offset in the drm device node's address space to be able to
112 * memory map a dumb buffer.
113 *
114 * Called by the user via ioctl.
115 *
116 * Returns:
117 * Zero on success, negative errno on failure.
118 */
119int drm_mode_mmap_dumb_ioctl(struct drm_device *dev,
120			     void *data, struct drm_file *file_priv)
121{
122	struct drm_mode_map_dumb *args = data;
123
124	if (!dev->driver->dumb_create)
125		return -ENOSYS;
126
127	if (dev->driver->dumb_map_offset)
128		return dev->driver->dumb_map_offset(file_priv, dev,
129						    args->handle,
130						    &args->offset);
131	else
132		return drm_gem_dumb_map_offset(file_priv, dev, args->handle,
133					       &args->offset);
134}
135
136int drm_mode_destroy_dumb(struct drm_device *dev, u32 handle,
137			  struct drm_file *file_priv)
138{
139	if (!dev->driver->dumb_create)
140		return -ENOSYS;
141
142	if (dev->driver->dumb_destroy)
143		return dev->driver->dumb_destroy(file_priv, dev, handle);
144	else
145		return drm_gem_dumb_destroy(file_priv, dev, handle);
146}
147
148int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
149				void *data, struct drm_file *file_priv)
150{
151	struct drm_mode_destroy_dumb *args = data;
152
153	return drm_mode_destroy_dumb(dev, args->handle, file_priv);
154}