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| author | Paul Cercueil <paul@crapouillou.net> | 2024-06-20 14:27:22 +0200 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2024-06-30 11:29:17 +0100 |
| commit | 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f (patch) | |
| tree | 3eb41c082b778512c60a7ead6576debfc640db54 /drivers/iio/Kconfig | |
| parent | da5a6fa00170cf8beb5fcc31566ef39547f7c2d9 (diff) | |
| download | lwn-3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f.tar.gz lwn-3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f.zip | |
iio: core: Add new DMABUF interface infrastructure
Add the necessary infrastructure to the IIO core to support a new
optional DMABUF based interface.
With this new interface, DMABUF objects (externally created) can be
attached to a IIO buffer, and subsequently used for data transfer.
A 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.
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 userful for high-speed
devices which produce several megabytes or even gigabytes of data per
second.
As part of the interface, 3 new IOCTLs have been added:
IIO_BUFFER_DMABUF_ATTACH_IOCTL(int fd):
Attach the DMABUF object identified by the given file descriptor to the
buffer.
IIO_BUFFER_DMABUF_DETACH_IOCTL(int fd):
Detach the DMABUF object identified by the given file descriptor from
the buffer. 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 *):
Request a data transfer to/from the given DMABUF object. Its file
descriptor, as well as the transfer size and flags are provided in the
"iio_dmabuf" structure.
These three IOCTLs have to be performed on the IIO buffer's file
descriptor, obtained using the IIO_BUFFER_GET_FD_IOCTL() ioctl.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Co-developed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20240620122726.41232-4-paul@crapouillou.net
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers/iio/Kconfig')
| -rw-r--r-- | drivers/iio/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig index 9c351ffc7bed..661127aed2f9 100644 --- a/drivers/iio/Kconfig +++ b/drivers/iio/Kconfig @@ -14,6 +14,7 @@ if IIO config IIO_BUFFER bool "Enable buffer support within IIO" + select DMA_SHARED_BUFFER help Provide core support for various buffer based data acquisition methods. |