From: Jon Hunter <jonathanh@nvidia.com>
To: Akhil R <akhilrajeev@nvidia.com>,
"christian.koenig@amd.com" <christian.koenig@amd.com>,
"digetx@gmail.com" <digetx@gmail.com>,
Laxman Dewangan <ldewangan@nvidia.com>,
"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
"sumit.semwal@linaro.org" <sumit.semwal@linaro.org>,
"thierry.reding@gmail.com" <thierry.reding@gmail.com>,
"wsa@kernel.org" <wsa@kernel.org>
Subject: Re: [PATCH v3] i2c: tegra: Share same DMA channel for RX and TX
Date: Wed, 22 Mar 2023 13:42:21 +0000 [thread overview]
Message-ID: <b9235dfc-10dc-1ed0-1510-fd98902491e3@nvidia.com> (raw)
In-Reply-To: <SJ1PR12MB6339FC0B9BB57D1D2300D46CC0869@SJ1PR12MB6339.namprd12.prod.outlook.com>
On 22/03/2023 12:00, Akhil R wrote:
>> On 22/03/2023 10:24, Akhil R wrote:
>>> Allocate only one DMA channel for I2C and share it for both TX and RX
>>> instead of using two different DMA hardware channels with the same
>>> slave ID. Since I2C supports only half duplex, there is no impact on
>>> perf with this.
>>>
>>> Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
>>
>> Just to confirm. This impacts all Tegra devices from Tegra20 to the
>> latest. Does this work for all Tegra and the different DMA controllers
>> that they have?
>>
> Yes, It should. I could see in the APB DMA driver that the same channel
> could be used for TX and RX and the direction is configured only during
> dma_prep_*() calls.
> I did not test it on a Tegra with APB DMA, but since it works very similar
> to GPC DMA there should not be any impact.
OK. BTW, this does not apply cleanly on top of -next. It appears that
this is based on top "i2c: tegra: Fix PEC support for SMBUS block read"
and that one needs to be applied first. This can be avoided if you send
as a series.
Jon
--
nvpublic
next prev parent reply other threads:[~2023-03-22 13:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-22 10:24 [PATCH v3] i2c: tegra: Share same DMA channel for RX and TX Akhil R
2023-03-22 11:07 ` Jon Hunter
2023-03-22 12:00 ` Akhil R
2023-03-22 13:42 ` Jon Hunter [this message]
2023-03-23 9:26 ` Akhil R
2023-03-23 9:50 ` Thierry Reding
2023-03-23 12:16 ` Akhil R
2023-03-23 13:52 ` Thierry Reding
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=b9235dfc-10dc-1ed0-1510-fd98902491e3@nvidia.com \
--to=jonathanh@nvidia.com \
--cc=akhilrajeev@nvidia.com \
--cc=christian.koenig@amd.com \
--cc=digetx@gmail.com \
--cc=ldewangan@nvidia.com \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=sumit.semwal@linaro.org \
--cc=thierry.reding@gmail.com \
--cc=wsa@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.