On Mon, 7 Feb 2022 12:59:21 +0000 Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote: > Hi Jonathan, > > This is the V2 of my patchset that introduces a new userspace interface > based on DMABUF objects to complement the fileio API, and adds write() > support to the existing fileio API. Hi Paul, It's been a little while. Perhaps you could summarize the various view points around the appropriateness of using DMABUF for this? I appreciate it is a tricky topic to distil into a brief summary but I know I would find it useful even if no one else does! Thanks, Jonathan > > Changes since v1: > > - the patches that were merged in v1 have been (obviously) dropped from > this patchset; > - the patch that was setting the write-combine cache setting has been > dropped as well, as it was simply not useful. > - [01/12]: > * Only remove the outgoing queue, and keep the incoming queue, as we > want the buffer to start streaming data as soon as it is enabled. > * Remove IIO_BLOCK_STATE_DEQUEUED, since it is now functionally the > same as IIO_BLOCK_STATE_DONE. > - [02/12]: > * Fix block->state not being reset in > iio_dma_buffer_request_update() for output buffers. > * Only update block->bytes_used once and add a comment about why we > update it. > * Add a comment about why we're setting a different state for output > buffers in iio_dma_buffer_request_update() > * Remove useless cast to bool (!!) in iio_dma_buffer_io() > - [05/12]: > Only allow the new IOCTLs on the buffer FD created with > IIO_BUFFER_GET_FD_IOCTL(). > - [12/12]: > * Explicitly state that the new interface is optional and is > not implemented by all drivers. > * The IOCTLs can now only be called on the buffer FD returned by > IIO_BUFFER_GET_FD_IOCTL. > * Move the page up a bit in the index since it is core stuff and not > driver-specific. > > The patches not listed here have not been modified since v1. > > Cheers, > -Paul > > Alexandru Ardelean (1): > iio: buffer-dma: split iio_dma_buffer_fileio_free() function > > Paul Cercueil (11): > iio: buffer-dma: Get rid of outgoing queue > iio: buffer-dma: Enable buffer write support > iio: buffer-dmaengine: Support specifying buffer direction > iio: buffer-dmaengine: Enable write support > iio: core: Add new DMABUF interface infrastructure > iio: buffer-dma: Use DMABUFs instead of custom solution > iio: buffer-dma: Implement new DMABUF based userspace API > iio: buffer-dmaengine: Support new DMABUF based userspace API > iio: core: Add support for cyclic buffers > iio: buffer-dmaengine: Add support for cyclic buffers > Documentation: iio: Document high-speed DMABUF based API > > Documentation/driver-api/dma-buf.rst | 2 + > Documentation/iio/dmabuf_api.rst | 94 +++ > Documentation/iio/index.rst | 2 + > drivers/iio/adc/adi-axi-adc.c | 3 +- > drivers/iio/buffer/industrialio-buffer-dma.c | 610 ++++++++++++++---- > .../buffer/industrialio-buffer-dmaengine.c | 42 +- > drivers/iio/industrialio-buffer.c | 60 ++ > include/linux/iio/buffer-dma.h | 38 +- > include/linux/iio/buffer-dmaengine.h | 5 +- > include/linux/iio/buffer_impl.h | 8 + > include/uapi/linux/iio/buffer.h | 30 + > 11 files changed, 749 insertions(+), 145 deletions(-) > create mode 100644 Documentation/iio/dmabuf_api.rst >
