From: Jon Hunter <jonathanh@nvidia.com>
To: Dmitry Osipenko <digetx@gmail.com>,
Peter Ujfalusi <peter.ujfalusi@ti.com>,
Sameer Pujar <spujar@nvidia.com>, Vinod Koul <vkoul@kernel.org>
Cc: <dan.j.williams@intel.com>, <tiwai@suse.com>,
<dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<sharadg@nvidia.com>, <rlokhande@nvidia.com>,
<dramesh@nvidia.com>, <mkumard@nvidia.com>,
linux-tegra <linux-tegra@vger.kernel.org>
Subject: Re: [PATCH] [RFC] dmaengine: add fifo_size member
Date: Fri, 7 Jun 2019 10:24:00 +0100 [thread overview]
Message-ID: <a931c88c-0741-4332-832a-77458b55bfef@nvidia.com> (raw)
In-Reply-To: <457eb5e1-40cc-8c0f-e21c-3881c3c04de2@gmail.com>
On 06/06/2019 18:25, Dmitry Osipenko wrote:
> 06.06.2019 19:53, Jon Hunter пишет:
>>
>> On 06/06/2019 17:44, Dmitry Osipenko wrote:
>>> 06.06.2019 19:32, Jon Hunter пишет:
>>>>
>>>> On 06/06/2019 16:18, Dmitry Osipenko wrote:
>>>>
>>>> ...
>>>>
>>>>>>> If I understood everything correctly, the FIFO buffer is shared among
>>>>>>> all of the ADMA clients and hence it should be up to the ADMA driver to
>>>>>>> manage the quotas of the clients. So if there is only one client that
>>>>>>> uses ADMA at a time, then this client will get a whole FIFO buffer, but
>>>>>>> once another client starts to use ADMA, then the ADMA driver will have
>>>>>>> to reconfigure hardware to split the quotas.
>>>>>>
>>>>>> The FIFO quotas are managed by the ADMAIF driver (does not exist in
>>>>>> mainline currently but we are working to upstream this) because it is
>>>>>> this device that owns and needs to configure the FIFOs. So it is really
>>>>>> a means to pass the information from the ADMAIF to the ADMA.
>>>>>
>>>>> So you'd want to reserve a larger FIFO for an audio channel that has a
>>>>> higher audio rate since it will perform reads more often. You could also
>>>>> prioritize one channel over the others, like in a case of audio call for
>>>>> example.
>>>>>
>>>>> Is the shared buffer smaller than may be needed by clients in a worst
>>>>> case scenario? If you could split the quotas statically such that each
>>>>> client won't ever starve, then seems there is no much need in the
>>>>> dynamic configuration.
>>>>
>>>> Actually, this is still very much relevant for the static case. Even if
>>>> we defined a static configuration of the FIFO mapping in the ADMAIF
>>>> driver we still need to pass this information to the ADMA. I don't
>>>> really like the idea of having it statically defined in two different
>>>> drivers.
>>>
>>> Ah, so you need to apply the same configuration in two places. Correct?
>>>
>>> Are ADMAIF and ADMA really two different hardware blocks? Or you
>>> artificially decoupled the ADMA driver?
>>
>> These are two different hardware modules with their own register sets.
>> Yes otherwise, it would be a lot simpler!
>
> The register sets are indeed separated, but it looks like that ADMAIF is
> really a part of ADMA that is facing to Audio Crossbar. No? What is the
> purpose of ADMAIF? Maybe you could amend the ADMA hardware description
> with the ADMAIF addition until it's too late.
The ADMA can perform the following transfers (per the CH_CONFIG
register) ...
MEMORY_TO_MEMORY
AHUB_TO_MEMORY
MEMORY_TO_AHUB
AHUB_TO_AHUB
Hence it is possible to use the ADMA to do memory-to-memory transfers
that do not involve the ADMAIF.
So no the ADMAIF is not part of the ADMA. It is purely the interface to
the crossbar (AHUB/APE), but from a hardware standpoint they are
separate. And so no we will not amend the hardware description.
Jon
--
nvpublic
next prev parent reply other threads:[~2019-06-07 9:24 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-30 11:30 [RFC] dmaengine: add fifo_size member Sameer Pujar
2019-04-30 11:30 ` [PATCH] " Sameer Pujar
2019-05-02 6:04 ` Vinod Koul
2019-05-02 6:04 ` [PATCH] " Vinod Koul
2019-05-02 10:53 ` Sameer Pujar
2019-05-02 12:25 ` Vinod Koul
2019-05-02 13:29 ` Sameer Pujar
2019-05-03 19:10 ` Peter Ujfalusi
2019-05-04 10:23 ` Vinod Koul
2019-05-06 13:04 ` Sameer Pujar
2019-05-06 15:50 ` Vinod Koul
2019-06-06 3:49 ` Sameer Pujar
2019-06-06 6:00 ` Peter Ujfalusi
2019-06-06 6:41 ` Sameer Pujar
2019-06-06 7:14 ` Jon Hunter
2019-06-06 10:22 ` Peter Ujfalusi
2019-06-06 10:49 ` Jon Hunter
2019-06-06 11:54 ` Peter Ujfalusi
2019-06-06 12:37 ` Jon Hunter
2019-06-06 13:45 ` Dmitry Osipenko
2019-06-06 13:55 ` Dmitry Osipenko
2019-06-06 14:26 ` Jon Hunter
2019-06-06 14:36 ` Jon Hunter
2019-06-06 14:36 ` Dmitry Osipenko
2019-06-06 14:47 ` Jon Hunter
2019-06-06 14:25 ` Jon Hunter
2019-06-06 15:18 ` Dmitry Osipenko
2019-06-06 16:32 ` Jon Hunter
2019-06-06 16:44 ` Dmitry Osipenko
2019-06-06 16:53 ` Jon Hunter
2019-06-06 17:25 ` Dmitry Osipenko
2019-06-06 17:56 ` Dmitry Osipenko
2019-06-07 9:24 ` Jon Hunter [this message]
2019-06-07 5:50 ` Peter Ujfalusi
2019-06-07 9:18 ` Jon Hunter
2019-06-07 10:27 ` Jon Hunter
2019-06-07 12:17 ` Peter Ujfalusi
2019-06-07 12:58 ` Jon Hunter
2019-06-07 13:35 ` Peter Ujfalusi
2019-06-07 20:53 ` Dmitry Osipenko
2019-06-10 8:01 ` Jon Hunter
2019-06-10 7:59 ` Jon Hunter
2019-06-13 4:43 ` Vinod Koul
2019-06-17 7:07 ` Sameer Pujar
2019-06-18 4:33 ` Vinod Koul
2019-06-20 10:29 ` Sameer Pujar
2019-06-24 6:26 ` Vinod Koul
2019-06-25 2:57 ` Sameer Pujar
2019-07-05 6:15 ` Sameer Pujar
2019-07-15 15:42 ` Sameer Pujar
2019-07-19 5:04 ` Vinod Koul
2019-07-23 5:54 ` Sameer Pujar
2019-07-29 6:10 ` Vinod Koul
2019-07-31 9:48 ` Jon Hunter
2019-07-31 15:16 ` Vinod Koul
2019-08-02 8:51 ` Jon Hunter
2019-08-08 12:38 ` Vinod Koul
2019-08-19 15:56 ` Jon Hunter
2019-08-20 11:05 ` Vinod Koul
2019-09-16 9:02 ` Sameer Pujar
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=a931c88c-0741-4332-832a-77458b55bfef@nvidia.com \
--to=jonathanh@nvidia.com \
--cc=dan.j.williams@intel.com \
--cc=digetx@gmail.com \
--cc=dmaengine@vger.kernel.org \
--cc=dramesh@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=mkumard@nvidia.com \
--cc=peter.ujfalusi@ti.com \
--cc=rlokhande@nvidia.com \
--cc=sharadg@nvidia.com \
--cc=spujar@nvidia.com \
--cc=tiwai@suse.com \
--cc=vkoul@kernel.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).