From: "Nuno Sá" <noname.nuno@gmail.com>
To: Paul Cercueil <paul@crapouillou.net>,
Jonathan Cameron <jic23@kernel.org>
Cc: "Michael Hennerich" <Michael.Hennerich@analog.com>,
"Lars-Peter Clausen" <lars@metafoo.de>,
"Christian König" <christian.koenig@amd.com>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Jonathan Corbet" <corbet@lwn.net>,
"Alexandru Ardelean" <ardeleanalex@gmail.com>,
dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-iio@vger.kernel.org
Subject: Re: [PATCH v2 02/12] iio: buffer-dma: Enable buffer write support
Date: Tue, 29 Mar 2022 09:11:48 +0200 [thread overview]
Message-ID: <deb2cd86196addbc47908455880000c618b984be.camel@gmail.com> (raw)
In-Reply-To: <96XG9R.3NOIIEN7IS001@crapouillou.net>
On Mon, 2022-03-28 at 19:39 +0100, Paul Cercueil wrote:
> Hi Jonathan,
>
> Le lun., mars 28 2022 at 18:24:09 +0100, Jonathan Cameron
> <jic23@kernel.org> a écrit :
> > On Mon, 7 Feb 2022 12:59:23 +0000
> > Paul Cercueil <paul@crapouillou.net> wrote:
> >
> > > Adding write support to the buffer-dma code is easy - the
> > > write()
> > > function basically needs to do the exact same thing as the
> > > read()
> > > function: dequeue a block, read or write the data, enqueue the
> > > block
> > > when entirely processed.
> > >
> > > Therefore, the iio_buffer_dma_read() and the new
> > > iio_buffer_dma_write()
> > > now both call a function iio_buffer_dma_io(), which will perform
> > > this
> > > task.
> > >
> > > The .space_available() callback can return the exact same value
> > > as
> > > the
> > > .data_available() callback for input buffers, since in both
> > > cases we
> > > count the exact same thing (the number of bytes in each
> > > available
> > > block).
> > >
> > > Note that we preemptively reset block->bytes_used to the
> > > buffer's
> > > size
> > > in iio_dma_buffer_request_update(), as in the future the
> > > iio_dma_buffer_enqueue() function won't reset it.
> > >
> > > v2: - 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()
> > >
> > > Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> > > Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
> > One comment inline.
> >
> > I'd be tempted to queue this up with that fixed, but do we have
> > any users? Even though it's trivial I'm not that keen on code
> > upstream well in advance of it being used.
>
> There's a userspace user in libiio. On the kernel side we do have
> drivers that use it in ADI's downstream kernel, that we plan to
> upstream in the long term (but it can take some time, as we need to
> upstream other things first, like JESD204B support).
>
>
You mean, users for DMA output buffers? If so, I have on my queue to
add the dac counterpart of this one:
https://elixir.bootlin.com/linux/latest/source/drivers/iio/adc/adi-axi-adc.c
Which is a user of DMA buffers. Though this one does not depend on
JESD204, I suspect it will also be a tricky process mainly because I
think there are major issues on how things are done right now (on the
ADC driver).
But yeah, not a topic here and I do plan to first start the discussion
on the mailing list before starting developing (hopefully in the coming
weeks)...
- Nuno Sá
next prev parent reply other threads:[~2022-03-29 7:11 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-07 12:59 [PATCH v2 00/12] iio: buffer-dma: write() and new DMABUF based API Paul Cercueil
2022-02-07 12:59 ` [PATCH v2 01/12] iio: buffer-dma: Get rid of outgoing queue Paul Cercueil
2022-02-13 18:57 ` Jonathan Cameron
2022-02-13 19:25 ` Paul Cercueil
2022-03-28 17:17 ` Jonathan Cameron
2022-02-07 12:59 ` [PATCH v2 02/12] iio: buffer-dma: Enable buffer write support Paul Cercueil
2022-03-28 17:24 ` Jonathan Cameron
2022-03-28 18:39 ` Paul Cercueil
2022-03-29 7:11 ` Nuno Sá [this message]
2022-03-28 20:38 ` Andy Shevchenko
2022-02-07 12:59 ` [PATCH v2 03/12] iio: buffer-dmaengine: Support specifying buffer direction Paul Cercueil
2022-02-07 12:59 ` [PATCH v2 04/12] iio: buffer-dmaengine: Enable write support Paul Cercueil
2022-03-28 17:28 ` Jonathan Cameron
2022-02-07 12:59 ` [PATCH v2 05/12] iio: core: Add new DMABUF interface infrastructure Paul Cercueil
2022-03-28 17:37 ` Jonathan Cameron
2022-03-28 18:44 ` Paul Cercueil
2022-03-29 13:36 ` Jonathan Cameron
2022-03-28 20:46 ` Andy Shevchenko
2022-02-07 12:59 ` [PATCH v2 06/12] iio: buffer-dma: split iio_dma_buffer_fileio_free() function Paul Cercueil
2022-02-07 12:59 ` [PATCH v2 07/12] iio: buffer-dma: Use DMABUFs instead of custom solution Paul Cercueil
2022-03-28 17:54 ` Jonathan Cameron
2022-03-28 17:54 ` Christian König
2022-03-28 19:16 ` Paul Cercueil
2022-03-28 20:58 ` Andy Shevchenko
2022-02-07 12:59 ` [PATCH v2 08/12] iio: buffer-dma: Implement new DMABUF based userspace API Paul Cercueil
2022-02-07 12:59 ` [PATCH v2 09/12] iio: buffer-dmaengine: Support " Paul Cercueil
2022-02-07 12:59 ` [PATCH v2 10/12] iio: core: Add support for cyclic buffers Paul Cercueil
2022-02-07 13:01 ` [PATCH v2 11/12] iio: buffer-dmaengine: " Paul Cercueil
2022-02-07 13:01 ` [PATCH v2 12/12] Documentation: iio: Document high-speed DMABUF based API Paul Cercueil
2022-03-29 8:54 ` Daniel Vetter
2022-03-29 9:47 ` Paul Cercueil
2022-03-29 14:07 ` Daniel Vetter
2022-03-29 17:34 ` Paul Cercueil
2022-03-30 9:22 ` Daniel Vetter
2022-02-13 18:46 ` [PATCH v2 00/12] iio: buffer-dma: write() and new " Jonathan Cameron
2022-02-15 17:43 ` Paul Cercueil
2022-03-29 8:33 ` Daniel Vetter
2022-03-29 9:11 ` Paul Cercueil
2022-03-29 14:10 ` Daniel Vetter
2022-03-29 17:16 ` Paul Cercueil
2022-03-30 9:19 ` Daniel Vetter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=deb2cd86196addbc47908455880000c618b984be.camel@gmail.com \
--to=noname.nuno@gmail.com \
--cc=Michael.Hennerich@analog.com \
--cc=ardeleanalex@gmail.com \
--cc=christian.koenig@amd.com \
--cc=corbet@lwn.net \
--cc=dri-devel@lists.freedesktop.org \
--cc=jic23@kernel.org \
--cc=lars@metafoo.de \
--cc=linaro-mm-sig@lists.linaro.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-iio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=paul@crapouillou.net \
--cc=sumit.semwal@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).