From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
Lee Jones <lee.jones@linaro.org>,
Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Alim Akhtar <alim.akhtar@samsung.com>,
Dinh Nguyen <dinguyen@kernel.org>,
Michal Simek <michal.simek@xilinx.com>,
Liviu Dudau <liviu.dudau@arm.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
Broadcom Kernel Team <bcm-kernel-feedback-list@broadcom.com>,
Sylwester Nawrocki <s.nawrocki@samsung.com>,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Rob Herring <robh@kernel.org>
Subject: Re: [PATCH 08/10] ARM: dts: exynos: use proper 'dma-channels/requests' properties
Date: Thu, 28 Apr 2022 12:05:33 +0200 [thread overview]
Message-ID: <99c80fb6-c6cc-9370-b93d-ed736c7f2192@samsung.com> (raw)
In-Reply-To: <1399774c-f188-81f1-4d15-367b9d0e4a59@linaro.org>
On 28.04.2022 12:00, Krzysztof Kozlowski wrote:
> On 28/04/2022 11:57, Marek Szyprowski wrote:
>> On 28.04.2022 11:54, Krzysztof Kozlowski wrote:
>>> On 28/04/2022 11:50, Marek Szyprowski wrote:
>>>> On 27.04.2022 17:58, Krzysztof Kozlowski wrote:
>>>>> pl330 DMA controller bindings documented 'dma-channels' and
>>>>> 'dma-requests' properties (without leading hash sign), so fix the DTS to
>>>>> match the bindings.
>>>>>
>>>>> Reported-by: Rob Herring <robh@kernel.org>
>>>>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>>>> Are those properties really needed for PL330 driver on Exynos SoCs? I've
>>>> removed them and I still see the proper values read from registers and
>>>> reported in the log (Exynos4210):
>>>>
>>>> dma-pl330 12680000.dma-controller: Loaded driver for PL330 DMAC-141330
>>>> dma-pl330 12680000.dma-controller: DBUFF-32x4bytes Num_Chans-8
>>>> Num_Peri-32 Num_Events-32
>>>> dma-pl330 12690000.dma-controller: Loaded driver for PL330 DMAC-141330
>>>> dma-pl330 12690000.dma-controller: DBUFF-32x4bytes Num_Chans-8
>>>> Num_Peri-32 Num_Events-32
>>>> dma-pl330 12850000.dma-controller: Loaded driver for PL330 DMAC-141330
>>>> dma-pl330 12850000.dma-controller: DBUFF-64x8bytes Num_Chans-8
>>>> Num_Peri-1 Num_Events-32
>>>>
>>>> I also don't see any code that would read those properties. IMHO they
>>>> should be simply removed at all, at least for the PL330 related nodes.
>>> In current Linux implementation they indeed are not used. Nothing parses
>>> them. However:
>>> 1. They describe (hopefully correct) the hardware.
>>> 2. They might be used by other implementations of pl330 driver.
>>>
>>> I would not remove them from existing sources, but indeed maybe there is
>>> no need to add for new files.
>> What's the point in having dt properties duplicating data that might be
>> read from the driver registers?
> Hm, indeed, there is no point in this. Since they are read from
> registers, what was the idea behind in commit 42cf20980cde?
#dma-cells is indeed required, but the rest seems to be the cargo-cult
of some kind.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2022-04-28 10:11 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-27 15:58 [PATCH 00/10] ARM/arm64: dts: use proper 'dma-channels/requests' properties Krzysztof Kozlowski
2022-04-27 15:58 ` [PATCH 01/10] ARM: dts: zynq-7000: " Krzysztof Kozlowski
2022-04-28 6:24 ` Michal Simek
2022-04-27 15:58 ` [PATCH 02/10] ARM: dts: socfpga: " Krzysztof Kozlowski
2022-04-27 15:58 ` [PATCH 03/10] arm64: dts: stratix10/agilex: " Krzysztof Kozlowski
2022-04-27 15:58 ` [PATCH 04/10] arm64: dts: juno: " Krzysztof Kozlowski
2022-04-28 10:43 ` Robin Murphy
2022-04-28 10:45 ` Krzysztof Kozlowski
2022-04-27 15:58 ` [PATCH 05/10] arm64: dts: broadcom: " Krzysztof Kozlowski
2022-04-27 15:58 ` [PATCH 06/10] dt-bindings: mfd: samsung,exynos5433-lpass: fix " Krzysztof Kozlowski
2022-04-27 16:41 ` Alim Akhtar
2022-04-27 18:25 ` Rob Herring
2022-04-28 9:53 ` Lee Jones
2022-04-27 15:58 ` [PATCH 07/10] ARM: dts: s5pv210: use proper " Krzysztof Kozlowski
2022-04-27 16:45 ` Alim Akhtar
2022-04-27 15:58 ` [PATCH 08/10] ARM: dts: exynos: " Krzysztof Kozlowski
2022-04-27 16:44 ` Alim Akhtar
2022-04-28 9:50 ` Marek Szyprowski
2022-04-28 9:54 ` Krzysztof Kozlowski
2022-04-28 9:57 ` Marek Szyprowski
2022-04-28 10:00 ` Krzysztof Kozlowski
2022-04-28 10:05 ` Marek Szyprowski [this message]
2022-04-28 10:09 ` Krzysztof Kozlowski
2022-04-28 13:33 ` Rob Herring
2022-04-28 9:55 ` Alim Akhtar
2022-04-27 15:58 ` [PATCH 09/10] arm64: " Krzysztof Kozlowski
2022-04-27 16:46 ` Alim Akhtar
2022-04-27 15:58 ` [PATCH 10/10] arm64: dts: fsd: " Krzysztof Kozlowski
2022-04-27 16:49 ` Alim Akhtar
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=99c80fb6-c6cc-9370-b93d-ed736c7f2192@samsung.com \
--to=m.szyprowski@samsung.com \
--cc=alim.akhtar@samsung.com \
--cc=bcm-kernel-feedback-list@broadcom.com \
--cc=devicetree@vger.kernel.org \
--cc=dinguyen@kernel.org \
--cc=krzysztof.kozlowski+dt@linaro.org \
--cc=krzysztof.kozlowski@linaro.org \
--cc=lee.jones@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-samsung-soc@vger.kernel.org \
--cc=liviu.dudau@arm.com \
--cc=lorenzo.pieralisi@arm.com \
--cc=michal.simek@xilinx.com \
--cc=rjui@broadcom.com \
--cc=robh+dt@kernel.org \
--cc=robh@kernel.org \
--cc=s.nawrocki@samsung.com \
--cc=sbranden@broadcom.com \
--cc=sudeep.holla@arm.com \
/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).