From: Viresh Kumar <viresh.kumar@linaro.org>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: ALKML <linux-arm-kernel@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
DTML <devicetree@vger.kernel.org>,
Roy Franz <roy.franz@cavium.com>,
Harb Abdulhamid <harba@codeaurora.org>,
Nishanth Menon <nm@ti.com>, Arnd Bergmann <arnd@arndb.de>,
Loc Ho <lho@apm.com>, Alexey Klimov <alexey.klimov@arm.com>,
Ryan Harkin <Ryan.Harkin@arm.com>,
Jassi Brar <jassisinghbrar@gmail.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-pm@vger.kernel.org
Subject: Re: [PATCH v2 17/18] cpufreq: add support for CPU DVFS based on SCMI message protocol
Date: Wed, 9 Aug 2017 15:36:51 +0530 [thread overview]
Message-ID: <20170809100651.GA29383@vireshk-i7> (raw)
In-Reply-To: <97497123-2c24-6297-2d12-4f407d101b66@arm.com>
On 09-08-17, 10:59, Sudeep Holla wrote:
> On 09/08/17 05:18, Viresh Kumar wrote:
> > This stores the same handle pointer which is stored in the global variable
> > below. Right? Why keep a local variable here at all ?
>
> Yes, you are right. Initially, started with just private pointers and
> then added global. I was thinking of calling devm_scmi_handle_get per
> policy to reflect the refcount correctly and drop global variable. Let
> me know what you think.
A refcount of 1 should be fine as well, i.e. For the cpufreq driver. Why would
SCMI care if we manage multiple policies here ? Unless it makes something within
SCMI core better.
> > This is something special which is used only when we are returning indexes and
> > I am not sure if this will have benefit here. I will rather return 0 here.
> > That's what other drivers are doing.
>
> Indeed had 0 initially but changed as per Juri's suggestion.
Maybe he suggested doing that in the fast switch routine ? As that's the normal
protocol there. Though I have sent a patch today to propose using 0 there as
well (you cc'd).
> But is 0
> treated as failure and still running at current OPP ?
You have used that in the ->get() routine. So the OPP isn't changing, but we are
just trying to fetch it. cpufreq core doesn't do a lot with the value returned
from here, but at one place we break early if 0 is returned. And so all drivers
are returning that.
> and not 0KHz I assume.
Yeah, 0 KHz is dead CPU really :)
> > I suppose any CPU can change the frequency of any other CPU here, right? You
> > must set policy->dvfs_possible_from_any_cpu = true, from ->init() then.
> >
>
> OK, I missed to see something like that exists, will do.
Fairly recent stuff, present in pm/linux-next only.
> >> + /*
> >> + * But we need OPP table to function so if it is not there let's
> >> + * give platform code chance to provide it for us.
> >> + */
> >
> > How are we getting the OPPs? DT or non DT ?
> >
>
> Non DT :), from the firmware.
I would improve the above comment in that case to clearly say that OPPs are
added by the platform, lets wait for it.
--
viresh
next prev parent reply other threads:[~2017-08-09 10:06 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-04 14:31 [PATCH v2 00/18] firmware: ARM System Control and Management Interface(SCMI) support Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 01/18] dt-bindings: mailbox: add support for mailbox client shared memory Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 02/18] dt-bindings: arm: add support for ARM System Control and Management Interface(SCMI) protocol Sudeep Holla
2017-08-10 19:28 ` Rob Herring
2017-08-11 9:36 ` Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 03/18] firmware: arm_scmi: add basic driver infrastructure for SCMI Sudeep Holla
2017-08-08 2:46 ` Jassi Brar
2017-08-08 9:29 ` Sudeep Holla
2017-08-08 11:27 ` Jassi Brar
2017-09-05 10:03 ` Julien Thierry
2017-09-05 10:26 ` Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 04/18] firmware: arm_scmi: add common infrastructure and support for base protocol Sudeep Holla
2017-09-05 13:39 ` Julien Thierry
2017-09-05 13:45 ` Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 05/18] firmware: arm_scmi: add initial support for performance protocol Sudeep Holla
2017-09-05 15:04 ` Julien Thierry
2017-09-05 15:56 ` Julien Thierry
2017-09-05 16:54 ` Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 06/18] firmware: arm_scmi: add initial support for clock protocol Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 07/18] firmware: arm_scmi: add initial support for power protocol Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 08/18] firmware: arm_scmi: add initial support for sensor protocol Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 09/18] firmware: arm_scmi: probe and initialise all the supported protocols Sudeep Holla
2017-09-06 9:41 ` Julien Thierry
2017-09-06 13:31 ` Sudeep Holla
2017-09-06 13:41 ` Julien Thierry
2017-08-04 14:31 ` [PATCH v2 10/18] firmware: arm_scmi: add support for polling based SCMI transfers Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 11/18] firmware: arm_scmi: add option for polling based performance domain operations Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 12/18] firmware: arm_scmi: refactor in preparation to support per-protocol channels Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 13/18] firmware: arm_scmi: add per-protocol channels support using idr objects Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 14/18] firmware: arm_scmi: add device power domain support using genpd Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 15/18] clk: add support for clocks provided by SCMI Sudeep Holla
2017-09-01 0:19 ` Stephen Boyd
2017-09-04 13:37 ` Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 16/18] hwmon: add support for sensors exported via ARM SCMI Sudeep Holla
2017-08-04 19:32 ` Guenter Roeck
2017-08-07 12:25 ` Sudeep Holla
2017-08-14 15:09 ` Sudeep Holla
2017-08-14 18:04 ` Guenter Roeck
2017-08-04 14:31 ` [PATCH v2 17/18] cpufreq: add support for CPU DVFS based on SCMI message protocol Sudeep Holla
2017-08-09 4:18 ` Viresh Kumar
2017-08-09 9:59 ` Sudeep Holla
2017-08-09 10:06 ` Viresh Kumar [this message]
2017-08-09 10:15 ` Sudeep Holla
2017-08-04 14:31 ` [PATCH v2 18/18] cpufreq: scmi: add support for fast frequency switching Sudeep Holla
2017-08-09 4:28 ` Viresh Kumar
2017-08-09 10:09 ` Sudeep Holla
2017-08-09 10:13 ` Viresh Kumar
2017-08-09 10:17 ` Sudeep Holla
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