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From: Michal Simek <michal.simek@amd.com>
To: Leo Yan <leo.yan@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@arm.com>,
	James Clark <james.clark@linaro.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Wei Xu <xuwei5@hisilicon.com>,
	Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konradybcio@kernel.org>
Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH 1/5] dt-bindings: arm: coresight: Limit static replicator to atclk
Date: Mon, 12 Oct 2026 14:35:37 +0200	[thread overview]
Message-ID: <1128f456-ed6e-47ee-8dda-157af99cc404@amd.com> (raw)
In-Reply-To: <20261002-arm_coresight_hi3660_remove_dynamic_funnel_clocks-v1-1-c3edca1c480b@arm.com>



On 10/2/26 17:07, Leo Yan wrote:
> Static replicators have no programmable registers and need no APB
> programming clock.
> 
> The Zynq clock controller registers dbg_trc and dbg_apb and calls
> clk_prepare_enable() for each gate the bootloader left on. 

That's one bootloader behavior. If there is another bootloader that clocks can 
be simply disabled. I don't think there is any reason to depends on bootloader 
behavior. If there are clocks which has to be ON I can't see any reason not to 
drive them.

TRM page 741

Trace Port Clock The trace port clock is used to clock the TPIU and trace buffer 
when the MIO interface is chosen and must be twice the frequency of the desired 
TPIU clock. The TPIU clock frequency must be chosen to be fast enough to allow 
the trace port to keep up with the amount of data being traced, but slow enough 
to meet the dynamic characteristics of the data output buffers of the TPIU.

It means even Linux drivers are not handling that clocks that clocks should be 
handled hence described.

That's why I don't think the patch is correct.

Thanks,
Michal



  parent reply	other threads:[~2026-10-12 12:35 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-02 15:07 [PATCH 0/5] arm: coresight: Clean up funnel and replicator clocks Leo Yan
2026-10-02 15:07 ` [PATCH 1/5] dt-bindings: arm: coresight: Limit static replicator to atclk Leo Yan
2026-10-05 17:40   ` Rob Herring (Arm)
2026-10-12 12:35   ` Michal Simek [this message]
2026-10-12 16:28     ` Leo Yan
2026-10-13  5:53       ` Michal Simek
2026-10-02 15:07 ` [PATCH 2/5] dt-bindings: arm: coresight: Allow atclk for static funnel Leo Yan
2026-10-05 17:41   ` Rob Herring (Arm)
2026-10-02 15:07 ` [PATCH 3/5] arm64: dts: hisilicon: Drop PCLK from static CoreSight links Leo Yan
2026-10-09  1:04   ` Wei Xu
2026-10-02 15:07 ` [PATCH 4/5] ARM: dts: zynq: Use dynamic CoreSight funnel and trim clocks Leo Yan
2026-10-12 12:37   ` Michal Simek
2026-10-02 15:07 ` [PATCH 5/5] ARM: dts: qcom: apq8064: Drop PCLK from static replicator Leo Yan
2026-10-02 15:21   ` Dmitry Baryshkov
2026-10-02 15:33     ` Leo Yan
2026-10-02 16:05       ` Dmitry Baryshkov
2026-10-05 14:47         ` Leo Yan

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