/* * 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/drm_device.h> #include <drm/drm_drv.h> #include <drm/drm_dumb_buffers.h> #include <drm/drm_fourcc.h> #include <drm/drm_gem.h> #include <drm/drm_mode.h> #include <drm/drm_print.h> #include "drm_crtc_internal.h" #include "drm_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 &drm_driver.dumb_create * and &drm_driver.dumb_map_offset operations (the latter defaults to * drm_gem_dumb_map_offset() if not set). Drivers that don't use GEM handles * additionally need to implement the &drm_driver.dumb_destroy operation. See * the callbacks 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. */ static int drm_mode_align_dumb(struct drm_mode_create_dumb *args, unsigned long hw_pitch_align, unsigned long hw_size_align) { u32 pitch = args->pitch; u32 size; if (!pitch) return -EINVAL; if (hw_pitch_align) pitch = roundup(pitch, hw_pitch_align); if (!hw_size_align) hw_size_align = PAGE_SIZE; else if (!IS_ALIGNED(hw_size_align, PAGE_SIZE)) return -EINVAL; /* TODO: handle this if necessary */ if (check_mul_overflow(args->height, pitch, &size)) return -EINVAL; size = ALIGN(size, hw_size_align); if (!size) return -EINVAL; args->pitch = pitch; args->size = size; return 0; } /** * drm_mode_size_dumb - Calculates the scanline and buffer sizes for dumb buffers * @dev: DRM device * @args: Parameters for the dumb buffer * @hw_pitch_align: Hardware scanline alignment in bytes * @hw_size_align: Hardware buffer-size alignment in bytes * * The helper drm_mode_size_dumb() calculates the size of the buffer * allocation and the scanline size for a dumb buffer. Callers have to * set the buffers width, height and color mode in the argument @arg. * The helper validates the correctness of the input and tests for * possible overflows. If successful, it returns the dumb buffer's * required scanline pitch and size in &args. * * The parameter @hw_pitch_align allows the driver to specifies an * alignment for the scanline pitch, if the hardware requires any. The * calculated pitch will be a multiple of the alignment. The parameter * @hw_size_align allows to specify an alignment for buffer sizes. The * provided alignment should represent requirements of the graphics * hardware. drm_mode_size_dumb() handles GEM-related constraints * automatically across all drivers and hardware. For example, the * returned buffer size is always a multiple of PAGE_SIZE, which is * required by mmap(). * * Returns: * Zero on success, or a negative error code otherwise. */ int drm_mode_size_dumb(struct drm_device *dev, struct drm_mode_create_dumb *args, unsigned long hw_pitch_align, unsigned long hw_size_align) { u64 pitch = 0; u32 fourcc; /* * The scanline pitch depends on the buffer width and the color * format. The latter is specified as a color-mode constant for * which we first have to find the corresponding color format. * * Different color formats can have the same color-mode constant. * For example XRGB8888 and BGRX8888 both have a color mode of 32. * It is possible to use different formats for dumb-buffer allocation * and rendering as long as all involved formats share the same * color-mode constant. */ fourcc = drm_driver_color_mode_format(dev, args->bpp); if (fourcc != DRM_FORMAT_INVALID) { const struct drm_format_info *info = drm_format_info(fourcc); if (!info) return -EINVAL; pitch = drm_format_info_min_pitch(info, 0, args->width); } else if (args->bpp) { /* * Some userspace throws in arbitrary values for bpp and * relies on the kernel to figure it out. In this case we * fall back to the old method of using bpp directly. The * over-commitment of memory from the rounding is acceptable * for compatibility with legacy userspace. We have a number * of deprecated legacy values that are explicitly supported. */ switch (args->bpp) { default: drm_warn_once(dev, "Unknown color mode %u; guessing buffer size.\n", args->bpp); fallthrough; /* * These constants represent various YUV formats supported by * drm_gem_afbc_get_bpp(). */ case 12: // DRM_FORMAT_YUV420_8BIT case 15: // DRM_FORMAT_YUV420_10BIT case 30: // DRM_FORMAT_VUY101010 fallthrough; /* * Used by Mesa and Gstreamer to allocate NV formats and others * as RGB buffers. Technically, XRGB16161616F formats are RGB, * but the dumb buffers are not supposed to be used for anything * beyond 32 bits per pixels. */ case 10: // DRM_FORMAT_NV{15,20,30}, DRM_FORMAT_P010 case 64: // DRM_FORMAT_{XRGB,XBGR,ARGB,ABGR}16161616F pitch = args->width * DIV_ROUND_UP(args->bpp, SZ_8); break; } } if (!pitch || pitch > U32_MAX) return -EINVAL; args->pitch = pitch; return drm_mode_align_dumb(args, hw_pitch_align, hw_size_align); } EXPORT_SYMBOL(drm_mode_size_dumb); int drm_mode_create_dumb(struct drm_device *dev, struct drm_mode_create_dumb *args, struct drm_file *file_priv) { 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 */ if (args->bpp > U32_MAX - 8) return -EINVAL; cpp = DIV_ROUND_UP(args->bpp, 8); if (cpp > U32_MAX / args->width) return -EINVAL; stride = cpp * args->width; if (args->height > U32_MAX / 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); } int drm_mode_create_dumb_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv) { struct drm_mode_create_dumb *args = data; int err; err = drm_mode_create_dumb(dev, args, file_priv); if (err) { args->handle = 0; args->pitch = 0; args->size = 0; } return err; } static int drm_mode_mmap_dumb(struct drm_device *dev, struct drm_mode_map_dumb *args, struct drm_file *file_priv) { if (!dev->driver->dumb_create) return -ENOSYS; if (dev->driver->dumb_map_offset) return dev->driver->dumb_map_offset(file_priv, dev, args->handle, &args->offset); else return drm_gem_dumb_map_offset(file_priv, dev, args->handle, &args->offset); } /** * 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; int err; err = drm_mode_mmap_dumb(dev, args, file_priv); if (err) args->offset = 0; return err; } int drm_mode_destroy_dumb(struct drm_device *dev, u32 handle, struct drm_file *file_priv) { if (!dev->driver->dumb_create) return -ENOSYS; return drm_gem_handle_delete(file_priv, handle); } int drm_mode_destroy_dumb_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv) { struct drm_mode_destroy_dumb *args = data; return drm_mode_destroy_dumb(dev, args->handle, file_priv); }
