From: Rajendra Nayak <rnayak@codeaurora.org>
To: David Collins <collinsd@codeaurora.org>,
Ulf Hansson <ulf.hansson@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
Stephen Boyd <sboyd@kernel.org>,
Andy Gross <andy.gross@linaro.org>,
devicetree@vger.kernel.org,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/6] soc: qcom: rpmpd: Add a powerdomain driver to model corners
Date: Thu, 31 May 2018 09:23:53 +0530 [thread overview]
Message-ID: <e64cdb1b-6ebe-f8aa-d50d-dd925ca34ba7@codeaurora.org> (raw)
In-Reply-To: <7432f626-69cd-3535-04bc-de42e0285d41@codeaurora.org>
Hi David,
On 05/30/2018 11:57 PM, David Collins wrote:
> Hello Rajendra,
>
> On 05/30/2018 03:14 AM, Rajendra Nayak wrote:
>> On 05/30/2018 02:47 PM, Ulf Hansson wrote:
>>> On 25 May 2018 at 12:01, Rajendra Nayak <rnayak@codeaurora.org> wrote:
> ...
>>>> + pm_genpd_init(&rpmpds[i]->pd, NULL, true);
>>>
>>> Question: Is there no hierarchical topology of the PM domains. No
>>> genpd subdomains?
>>
>> The hierarchy if any is all handled by the remote core (RPM in this case).
>> For Linux its just a flat view.
>
> There is one special case that we'll need to handle somehow. The APPS
> vlvl request for VDD_MX needs to be greater than or equal to the vlvl
> request for VDD_CX. Can you please add the necessary code to achieve
> this? RPMh hardware doesn't handle this hardware requirement due to
> concerns about modem use case latency.
Sure, I'll take a look at it.
>
> Please note that this is handled in a somewhat hacky manner [1] with the
> downstream rpmh-regulator driver by specifying VDD_MX as the parent of
> VDD_CX and VDD_MX_AO as the parent of VDD_CX_AO with a dropout voltage of
> -1. That way, enabling CX causes MX to be enabled and voltage level
> requests are propagated from CX to MX (the -1 is ignored because it is
> rounded up within the sparse vlvl numbering space).
I can't see how else to handle this but with a fake parent/child relation,
which also means we might need support to propagate performance states for
power domains up the parents, which I think was initially supported but
later dropped since we thought this wasn't needed for now.
We might need to take a re-look at it to support this usecase.
thanks,
Rajendra
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation
next prev parent reply other threads:[~2018-05-31 3:54 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-25 10:01 [PATCH v2 0/6] Add powerdomain driver for corners on msm8996/sdm845 Rajendra Nayak
2018-05-25 10:01 ` [PATCH v2 1/6] soc: qcom: rpmpd: Add a powerdomain driver to model corners Rajendra Nayak
2018-05-30 9:17 ` Ulf Hansson
2018-05-30 10:14 ` Rajendra Nayak
2018-05-30 12:44 ` Ulf Hansson
2018-05-31 4:20 ` Rajendra Nayak
2018-05-31 11:09 ` Ulf Hansson
2018-05-30 18:27 ` David Collins
2018-05-31 3:53 ` Rajendra Nayak [this message]
2018-05-31 3:27 ` Rob Herring
2018-05-31 4:14 ` Rajendra Nayak
2018-05-25 10:01 ` [PATCH v2 2/6] dt-bindings: opp: Introduce qcom-opp bindings Rajendra Nayak
2018-05-25 22:33 ` David Collins
2018-05-29 9:49 ` Rajendra Nayak
2018-05-25 10:01 ` [PATCH v2 3/6] soc: qcom: rpmpd: Add support for get/set performance state Rajendra Nayak
2018-05-25 10:01 ` [PATCH v2 4/6] arm64: dts: msm8996: Add rpmpd device node Rajendra Nayak
2018-05-25 10:01 ` [PATCH v2 5/6] soc: qcom: rpmh powerdomain driver Rajendra Nayak
2018-05-26 1:08 ` David Collins
2018-05-29 10:19 ` Rajendra Nayak
2018-05-29 19:03 ` David Collins
2018-05-30 8:55 ` Rajendra Nayak
2018-05-30 9:44 ` Viresh Kumar
2018-05-30 10:07 ` Rajendra Nayak
2018-06-01 8:48 ` Rajendra Nayak
2018-06-01 19:19 ` David Collins
2018-06-13 18:29 ` Lina Iyer
2018-05-31 3:31 ` Rob Herring
2018-05-31 4:15 ` Rajendra Nayak
2018-05-25 10:01 ` [PATCH v2 6/6] soc: qcom: rpmpd/rpmhpd: Add a max vote on all corners at init Rajendra Nayak
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