€•(/      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ&/translations/zh_CN/iio/iio_dmabuf_api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/zh_TW/iio/iio_dmabuf_api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/it_IT/iio/iio_dmabuf_api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/ja_JP/iio/iio_dmabuf_api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/ko_KR/iio/iio_dmabuf_api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/sp_SP/iio/iio_dmabuf_api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh£sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1h¡hhhžhhŸŒ@/var/lib/git/docbuild/linux/Documentation/iio/iio_dmabuf_api.rst”h KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ#High-speed DMABUF interface for IIO”h]”hŒ#High-speed DMABUF interface for IIO”…””}”(hh»hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hh¶hžhhŸh³h Kubhµ)”}”(hhh]”(hº)”}”(hŒ1. Overview”h]”hŒ1. Overview”…””}”(hhÌhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hhÉhžhhŸh³h KubhŒ	paragraph”“”)”}”(hŒŸThe Industrial I/O subsystem supports access to buffers through a
file-based interface, with read() and write() access calls through the
IIO device's dev node.”h]”hŒ¡The Industrial I/O subsystem supports access to buffers through a
file-based interface, with read() and write() access calls through the
IIO deviceâ€™s dev node.”…””}”(hhÜhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhŸh³h K
hhÉhžhubhÛ)”}”(hŒµIt additionally supports a DMABUF based interface, where the userspace
can attach DMABUF objects (externally created) to an IIO buffer, and
subsequently use them for data transfers.”h]”hŒµIt additionally supports a DMABUF based interface, where the userspace
can attach DMABUF objects (externally created) to an IIO buffer, and
subsequently use them for data transfers.”…””}”(hhêhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhŸh³h KhhÉhžhubhÛ)”}”(hŒÈA userspace application can then use this interface to share DMABUF
objects between several interfaces, allowing it to transfer data in a
zero-copy fashion, for instance between IIO and the USB stack.”h]”hŒÈA userspace application can then use this interface to share DMABUF
objects between several interfaces, allowing it to transfer data in a
zero-copy fashion, for instance between IIO and the USB stack.”…””}”(hhøhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhŸh³h KhhÉhžhubhÛ)”}”(hX	  The userspace application can also memory-map the DMABUF objects, and
access the sample data directly. The advantage of doing this vs. the
read() interface is that it avoids an extra copy of the data between the
kernel and userspace. This is particularly useful for high-speed devices
which produce several megabytes or even gigabytes of data per second.
It does however increase the userspace-kernelspace synchronization
overhead, as the DMA_BUF_SYNC_START and DMA_BUF_SYNC_END IOCTLs have to
be used for data integrity.”h]”hX	  The userspace application can also memory-map the DMABUF objects, and
access the sample data directly. The advantage of doing this vs. the
read() interface is that it avoids an extra copy of the data between the
kernel and userspace. This is particularly useful for high-speed devices
which produce several megabytes or even gigabytes of data per second.
It does however increase the userspace-kernelspace synchronization
overhead, as the DMA_BUF_SYNC_START and DMA_BUF_SYNC_END IOCTLs have to
be used for data integrity.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhŸh³h KhhÉhžhubeh}”(h]”Œoverview”ah ]”h"]”Œ1. overview”ah$]”h&]”uh1h´hh¶hžhhŸh³h Kubhµ)”}”(hhh]”(hº)”}”(hŒ2. User API”h]”hŒ2. User API”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hj  hžhhŸh³h K ubhÛ)”}”(hŒÊAs part of this interface, three new IOCTLs have been added. These three
IOCTLs have to be performed on the IIO buffer's file descriptor, which
can be obtained using the IIO_BUFFER_GET_FD_IOCTL() ioctl.”h]”hŒÌAs part of this interface, three new IOCTLs have been added. These three
IOCTLs have to be performed on the IIO bufferâ€™s file descriptor, which
can be obtained using the IIO_BUFFER_GET_FD_IOCTL() ioctl.”…””}”(hj-  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhŸh³h K"hj  hžhubhŒblock_quote”“”)”}”(hX  ``IIO_BUFFER_DMABUF_ATTACH_IOCTL(int fd)``
  Attach the DMABUF object, identified by its file descriptor, to the
  IIO buffer. Returns zero on success, and a negative errno value on
  error.

``IIO_BUFFER_DMABUF_DETACH_IOCTL(int fd)``
  Detach the given DMABUF object, identified by its file descriptor,
  from the IIO buffer. Returns zero on success, and a negative errno
  value on error.

  Note that closing the IIO buffer's file descriptor will
  automatically detach all previously attached DMABUF objects.

``IIO_BUFFER_DMABUF_ENQUEUE_IOCTL(struct iio_dmabuf *iio_dmabuf)``
  Enqueue a previously attached DMABUF object to the buffer queue.
  Enqueued DMABUFs will be read from (if output buffer) or written to
  (if input buffer) as long as the buffer is enabled.”h]”hŒdefinition_list”“”)”}”(hhh]”(hŒdefinition_list_item”“”)”}”(hŒ¹``IIO_BUFFER_DMABUF_ATTACH_IOCTL(int fd)``
Attach the DMABUF object, identified by its file descriptor, to the
IIO buffer. Returns zero on success, and a negative errno value on
error.
”h]”(hŒterm”“”)”}”(hŒ*``IIO_BUFFER_DMABUF_ATTACH_IOCTL(int fd)``”h]”hŒliteral”“”)”}”(hjP  h]”hŒ&IIO_BUFFER_DMABUF_ATTACH_IOCTL(int fd)”…””}”(hjT  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jR  hjN  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jL  hŸh³h K)hjH  ubhŒ
definition”“”)”}”(hhh]”hÛ)”}”(hŒAttach the DMABUF object, identified by its file descriptor, to the
IIO buffer. Returns zero on success, and a negative errno value on
error.”h]”hŒAttach the DMABUF object, identified by its file descriptor, to the
IIO buffer. Returns zero on success, and a negative errno value on
error.”…””}”(hjl  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhŸh³h K'hji  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjH  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jF  hŸh³h K)hjC  ubjG  )”}”(hX7  ``IIO_BUFFER_DMABUF_DETACH_IOCTL(int fd)``
Detach the given DMABUF object, identified by its file descriptor,
from the IIO buffer. Returns zero on success, and a negative errno
value on error.

Note that closing the IIO buffer's file descriptor will
automatically detach all previously attached DMABUF objects.
”h]”(jM  )”}”(hŒ*``IIO_BUFFER_DMABUF_DETACH_IOCTL(int fd)``”h]”jS  )”}”(hjŒ  h]”hŒ&IIO_BUFFER_DMABUF_DETACH_IOCTL(int fd)”…””}”(hjŽ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jR  hjŠ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jL  hŸh³h K1hj†  ubjh  )”}”(hhh]”(hÛ)”}”(hŒ•Detach the given DMABUF object, identified by its file descriptor,
from the IIO buffer. Returns zero on success, and a negative errno
value on error.”h]”hŒ•Detach the given DMABUF object, identified by its file descriptor,
from the IIO buffer. Returns zero on success, and a negative errno
value on error.”…””}”(hj¤  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhŸh³h K,hj¡  ubhÛ)”}”(hŒtNote that closing the IIO buffer's file descriptor will
automatically detach all previously attached DMABUF objects.”h]”hŒvNote that closing the IIO bufferâ€™s file descriptor will
automatically detach all previously attached DMABUF objects.”…””}”(hj²  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhŸh³h K0hj¡  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jg  hj†  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jF  hŸh³h K1hjC  ubjG  )”}”(hŒû``IIO_BUFFER_DMABUF_ENQUEUE_IOCTL(struct iio_dmabuf *iio_dmabuf)``
Enqueue a previously attached DMABUF object to the buffer queue.
Enqueued DMABUFs will be read from (if output buffer) or written to
(if input buffer) as long as the buffer is enabled.”h]”(jM  )”}”(hŒB``IIO_BUFFER_DMABUF_ENQUEUE_IOCTL(struct iio_dmabuf *iio_dmabuf)``”h]”jS  )”}”(hjÒ  h]”hŒ>IIO_BUFFER_DMABUF_ENQUEUE_IOCTL(struct iio_dmabuf *iio_dmabuf)”…””}”(hjÔ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jR  hjÐ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jL  hŸh³h K5hjÌ  ubjh  )”}”(hhh]”hÛ)”}”(hŒ¸Enqueue a previously attached DMABUF object to the buffer queue.
Enqueued DMABUFs will be read from (if output buffer) or written to
(if input buffer) as long as the buffer is enabled.”h]”hŒ¸Enqueue a previously attached DMABUF object to the buffer queue.
Enqueued DMABUFs will be read from (if output buffer) or written to
(if input buffer) as long as the buffer is enabled.”…””}”(hjê  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhŸh³h K4hjç  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjÌ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jF  hŸh³h K5hjC  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jA  hj=  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j;  hŸh³h K&hj  hžhubeh}”(h]”Œuser-api”ah ]”h"]”Œ2. user api”ah$]”h&]”uh1h´hh¶hžhhŸh³h K ubeh}”(h]”Œ#high-speed-dmabuf-interface-for-iio”ah ]”h"]”Œ#high-speed dmabuf interface for iio”ah$]”h&]”uh1h´hhhžhhŸh³h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h³uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¹NŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
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