From: Suzuki K Poulose <suzuki.poulose@arm•com>
To: andrew.murray@arm•com, mathieu.poirier@linaro•org,
alexander.shishkin@linux•intel.com
Cc: Al.Grant@arm•com, coresight@lists•linaro.org, leo.yan@linaro•org,
sudeep.holla@arm•com, linux-arm-kernel@lists•infradead.org,
mike.leach@linaro•org
Subject: Re: [PATCH v5 2/3] dt-bindings: arm: coresight: Add support for coresight-loses-context-with-cpu
Date: Thu, 12 Sep 2019 15:06:06 +0100 [thread overview]
Message-ID: <34570d2f-b9b7-a45e-8a52-86808198755b@arm.com> (raw)
In-Reply-To: <20190816154615.39854-3-andrew.murray@arm.com>
On 08/16/2019 04:46 PM, Andrew Murray wrote:
> Some coresight components, because of choices made during hardware
> integration, require their state to be saved and restored across CPU low
> power states.
>
> The software has no reliable method of detecting when save/restore is
> required thus let's add a binding to inform the kernel.
>
> Signed-off-by: Andrew Murray <andrew.murray@arm•com>
> ---
> Documentation/devicetree/bindings/arm/coresight.txt | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
> index fcc3bacfd8bc..d02c42d21f2f 100644
> --- a/Documentation/devicetree/bindings/arm/coresight.txt
> +++ b/Documentation/devicetree/bindings/arm/coresight.txt
> @@ -87,6 +87,15 @@ its hardware characteristcs.
>
> * port or ports: see "Graph bindings for Coresight" below.
>
> +* Optional properties for all components:
> +
> + * arm,coresight-loses-context-with-cpu : boolean. Indicates that the
> + hardware will lose register context on CPU power down (e.g. CPUIdle).
> + An example of where this may be needed are systems which contain a
> + coresight component and CPU in the same power domain. When the CPU
> + powers down the coresight component also powers down and loses its
> + context. This property is currently only used for the ETM 4.x driver.
> +
> * Optional properties for ETM/PTMs:
>
> * arm,cp14: must be present if the system accesses ETM/PTM management
>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm•com>
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next prev parent reply other threads:[~2019-09-12 14:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-16 15:46 [PATCH v5 0/3] coresight: etm4x: save/restore ETMv4 context across CPU low power states Andrew Murray
2019-08-16 15:46 ` [PATCH v5 1/3] coresight: etm4x: save/restore state " Andrew Murray
2019-08-20 21:55 ` Mathieu Poirier
2019-09-13 8:50 ` Andrew Murray
2019-09-12 14:03 ` Suzuki K Poulose
2019-09-13 9:20 ` Andrew Murray
2019-08-16 15:46 ` [PATCH v5 2/3] dt-bindings: arm: coresight: Add support for coresight-loses-context-with-cpu Andrew Murray
2019-08-20 21:59 ` Mathieu Poirier
2019-09-13 9:22 ` Andrew Murray
2019-09-12 14:06 ` Suzuki K Poulose [this message]
2019-08-16 15:46 ` [PATCH v5 3/3] coresight: etm4x: save/restore state for external agents Andrew Murray
2019-08-20 22:01 ` Mathieu Poirier
2019-09-12 15:35 ` Suzuki K Poulose
2019-09-13 10:32 ` Andrew Murray
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