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-rw-r--r--drivers/gpu/drm/drm_dumb_buffers.c154
1 files changed, 154 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 000000000..ad17fa21c
--- /dev/null
+++ b/drivers/gpu/drm/drm_dumb_buffers.c
@@ -0,0 +1,154 @@
+/*
+ * 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_gem.h>
+#include <drm/drm_mode.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.
+ */
+
+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)
+{
+ return drm_mode_create_dumb(dev, data, file_priv);
+}
+
+/**
+ * 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;
+
+ 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);
+}
+
+int drm_mode_destroy_dumb(struct drm_device *dev, u32 handle,
+ struct drm_file *file_priv)
+{
+ if (!dev->driver->dumb_create)
+ return -ENOSYS;
+
+ if (dev->driver->dumb_destroy)
+ return dev->driver->dumb_destroy(file_priv, dev, handle);
+ else
+ return drm_gem_dumb_destroy(file_priv, dev, 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);
+}