1# SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note 2# 3# (C) COPYRIGHT 2012-2013, 2020-2022 ARM Limited. All rights reserved. 4# 5# This program is free software and is provided to you under the terms of the 6# GNU General Public License version 2 as published by the Free Software 7# Foundation, and any use by you of this program is subject to the terms 8# of such GNU license. 9# 10# This program is distributed in the hope that it will be useful, 11# but WITHOUT ANY WARRANTY; without even the implied warranty of 12# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13# GNU General Public License for more details. 14# 15# You should have received a copy of the GNU General Public License 16# along with this program; if not, you can access it online at 17# http://www.gnu.org/licenses/gpl-2.0.html. 18# 19# 20 21===================== 22dma-buf-test-exporter 23===================== 24 25Overview 26-------- 27 28The dma-buf-test-exporter is a simple exporter of dma_buf objects. 29It has a private API to allocate and manipulate the buffers which are represented as dma_buf fds. 30The private API allows: 31* simple allocation of physically non-contiguous buffers 32* simple allocation of physically contiguous buffers 33* query kernel side API usage stats (number of attachments, number of mappings, mmaps) 34* failure mode configuration (fail attach, mapping, mmap) 35* kernel side memset of buffers 36 37The buffers support all of the dma_buf API, including mmap. 38 39It supports being compiled as a module both in-tree and out-of-tree. 40 41See include/uapi/base/arm/dma_buf_test_exporter/dma-buf-test-exporter.h for the ioctl interface. 42See Documentation/dma-buf-sharing.txt for details on dma_buf. 43