Re: [PATCH net-next v2 1/4] dt-bindings: dmaengine: bam_dma: Add "powered remotely" mode

From: Vinod Koul <vkoul@kernel.org>
To: Stephan Gerhold <stephan@gerhold.net>
Cc: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Loic Poulain <loic.poulain@linaro.org>,
	Sergey Ryazanov <ryazanov.s.a@gmail.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Andy Gross <agross@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Aleksander Morgado <aleksander@aleksander.es>,
	netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	dmaengine@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, phone-devel@vger.kernel.org,
	~postmarketos/upstreaming@lists.sr.ht,
	Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Subject: Re: [PATCH net-next v2 1/4] dt-bindings: dmaengine: bam_dma: Add "powered remotely" mode
Date: Mon, 18 Oct 2021 11:47:06 +0530	[thread overview]
Message-ID: <YW0RYufCyPi5JLo3@matsya> (raw)
In-Reply-To: <20211011141733.3999-2-stephan@gerhold.net>

On 11-10-21, 16:17, Stephan Gerhold wrote:
> In some configurations, the BAM DMA controller is set up by a remote
> processor and the local processor can simply start making use of it
> without setting up the BAM. This is already supported using the
> "qcom,controlled-remotely" property.
> 
> However, for some reason another possible configuration is that the
> remote processor is responsible for powering up the BAM, but we are
> still responsible for initializing it (e.g. resetting it etc). Add
> a "qcom,powered-remotely" property to describe that configuration.
> 
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
> ---
> Changes since RFC:
>   - Rename qcom,remote-power-collapse -> qcom,powered-remotely
>     for consistency with "qcom,controlled-remotely"
> 
> NOTE: This is *not* a compile-time requirement for the BAM-DMUX driver
>       so this could also go through the dmaengine tree.

Can we split that this to dmaengine & net series if there is not
dependency on the two... I think I skipped rev1 when I saw net-next

> 
> Also note that there is an ongoing effort to convert these bindings
> to DT schema but sadly there were not any updates for a while. :/
> https://lore.kernel.org/linux-arm-msm/20210519143700.27392-2-bhupesh.sharma@linaro.org/
> ---
>  Documentation/devicetree/bindings/dma/qcom_bam_dma.txt | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt
> index cf5b9e44432c..6e9a5497b3f2 100644
> --- a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt
> +++ b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt
> @@ -15,6 +15,8 @@ Required properties:
>    the secure world.
>  - qcom,controlled-remotely : optional, indicates that the bam is controlled by
>    remote proccessor i.e. execution environment.
> +- qcom,powered-remotely : optional, indicates that the bam is powered up by
> +  a remote processor but must be initialized by the local processor.
>  - num-channels : optional, indicates supported number of DMA channels in a
>    remotely controlled bam.
>  - qcom,num-ees : optional, indicates supported number of Execution Environments
> -- 
> 2.33.0

-- 
~Vinod