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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Stephen Boyd <sboyd@codeaurora.org>,
	Mike Turquette <mturquette@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Lists linaro-kernel <linaro-kernel@lists.linaro.org>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	Arvind Chauhan <arvind.chauhan@arm.com>,
	linux-arm-msm@vger.kernel.org, Sachin Kamat <spk.linux@gmail.com>,
	Thomas P Abraham <thomas.ab@samsung.com>,
	Shawn Guo <shawn.guo@linaro.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Nishanth Menon <nm@ti.com>, Tomasz Figa <t.figa@samsung.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Kukjin Kim <kgene.kim@samsung.com>,
	Michal Simek <michal.simek@xilinx.com>,
	Rob Herring <rob.herring@linaro.org>,
	Santosh Shilimkar <santosh.shilimkar@ti.com>,
	Simon Horman <horms@verge.net.au>
Subject: Re: [PATCH 00/14] cpufreq: cpu0: Extend support beyond CPU0, V2
Date: Thu, 3 Jul 2014 08:14:04 +0530	[thread overview]
Message-ID: <CAKohponRv6+rzJnO4cYFhXn6On1+4-KoxFSA2iU_nz130gvsug@mail.gmail.com> (raw)
In-Reply-To: <53B4B0B3.9080000@codeaurora.org>

On 3 July 2014 06:54, Stephen Boyd <sboyd@codeaurora.org> wrote:
> I gave it a spin. It works so you can have my
>
> Tested-by: Stephen Boyd <sboyd@codeaurora.org>

Thanks, all suggested improvements are made and pushed again with
your Tested-by..

> I'm still concerned about the patch where we figure out if the clocks
> are shared. I worry about a configuration where there are different
> clocks for on/off (i.e. gates) that are per-cpu but they all source from
> the same divider or something that is per-cluster. In DT this may be
> described as different clock provider outputs for the gates and in the
> cpu node we would have different clock specifiers but in reality all the
> CPUs in that cluster are affected by the same frequency scaling.

Yeah, this is probably what matches with Rob's doubt. These can
actually be different. Good point.

> In this case we'll need to get help from the clock framework to
> determine that those gates clocks don't have any .set_rate() callback so
> they can't actually change rate independently, and then walk up the tree
> to their parents to see if they have a common ancestor that does change
> rates. That's where it becomes useful to have a clock framework API for
> this, like clk_shares_rate(struct clk *clk, struct clk *peer) or
> something that can hide all this from cpufreq. Here's what I think it
> would look like (totally untested/uncompiled):
>
> static struct clk *find_rate_changer(struct clk *clk)
> {
>
>         if (!clk)
>                 return NULL;
>
>         do {
>                 /* Rate could change by changing parents */
>                 if (clk->num_parents > 1)
>                         return clk;
>
>                 /* Rate could change by calling clk_set_rate() */
>                 if (clk->ops->set_rate)
>                         return clk;
>
>                 /*
>                  * This is odd, clk_set_rate() doesn't propagate
>                  * and this clock can't change rate or parents
>                  * so we must be at the root and the clock we
>                  * started at can't change rates. Just return the
>                  * root so that we can see if the other clock shares
>                  * the same root although CPUfreq should never care.
>                  */
>                 if (!(clk->flags & CLK_SET_RATE_PARENT))
>                         return clk;
>         } while ((clk = clk->parent))
>
>         return NULL;
> }
>
> bool clk_shares_rate(struct clk *clk, struct clk *peer)
> {
>         struct clk *p1, *p2;
>
>         p1 = find_rate_changer(clk);
>         p2 = find_rate_changer(peer)
>
>         return p1 == p2;
> }

I find it much better then doing what I did initially, simply matching clk_get()
outputs. Lets see what Mike has to say..

@Mike: Is this less ugly ? :)

  reply	other threads:[~2014-07-03  2:44 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-01 16:32 Viresh Kumar
2014-07-01 16:32 ` [PATCH 01/14] of: Create of_property_match() Viresh Kumar
2014-07-01 16:32 ` [PATCH 02/14] clk: Create of_clk_shared_by_cpus() Viresh Kumar
2014-07-01 18:00   ` Stephen Boyd
2014-07-02  1:57     ` Viresh Kumar
2014-07-09 14:38   ` Santosh Shilimkar
2014-07-09 14:38     ` Santosh Shilimkar
2014-07-09 15:20     ` Viresh Kumar
     [not found]   ` <5f7164d789e87c62d722b575980c92dfd0504334.1404231535.git.viresh.kumar@linar o.org>
2014-07-28 14:01     ` Grant Likely
2014-07-28 14:01       ` Grant Likely
2014-07-01 16:32 ` [PATCH 03/14] cpufreq: Add support for per-policy driver data Viresh Kumar
2014-07-09 14:33   ` Santosh Shilimkar
2014-07-09 14:33     ` Santosh Shilimkar
2014-07-09 15:07     ` Viresh Kumar
2014-07-01 16:32 ` [PATCH 04/14] cpufreq: cpu0: Add Module Author Viresh Kumar
2014-07-09 14:42   ` Santosh Shilimkar
2014-07-09 14:42     ` Santosh Shilimkar
2014-07-09 15:08     ` Viresh Kumar
2014-07-09 15:24       ` Santosh Shilimkar
2014-07-01 16:32 ` [PATCH 05/14] cpufreq: cpu0: don't validate clock on clk_put() Viresh Kumar
2014-07-09 14:42   ` Santosh Shilimkar
2014-07-09 14:42     ` Santosh Shilimkar
2014-07-01 16:32 ` [PATCH 06/14] cpufreq: cpu0: defer probe if clock isn't registered yet Viresh Kumar
2014-07-02  5:53   ` Shawn Guo
2014-07-02  5:53     ` Shawn Guo
2014-07-02  5:55     ` Viresh Kumar
2014-07-02 11:32       ` Viresh Kumar
2014-07-03  0:38         ` Stephen Boyd
2014-07-03  2:19           ` Viresh Kumar
2014-07-09 14:43             ` Santosh Shilimkar
2014-07-09 14:43               ` Santosh Shilimkar
2014-07-01 16:32 ` [PATCH 07/14] cpufreq: cpu0: OPPs can be populated at runtime Viresh Kumar
2014-07-01 18:02   ` Stephen Boyd
2014-07-02  2:03     ` Viresh Kumar
2014-07-02  4:03   ` [PATCH V2 Resend " Viresh Kumar
2014-07-09 14:44   ` [PATCH " Santosh Shilimkar
2014-07-09 14:44     ` Santosh Shilimkar
2014-07-09 15:09     ` Viresh Kumar
2014-07-10 11:19     ` Viresh Kumar
2014-07-10 12:39       ` Nishanth Menon
2014-07-10 13:31         ` Santosh Shilimkar
2014-07-10 13:36           ` Viresh Kumar
2014-07-01 16:32 ` [PATCH 08/14] cpufreq: cpu0: use dev_{err|warn|dbg} instead of pr_{err|warn|debug} Viresh Kumar
2014-07-09 14:45   ` Santosh Shilimkar
2014-07-09 14:45     ` Santosh Shilimkar
2014-07-01 16:32 ` [PATCH 09/14] cpufreq: cpu0: Move per-cluster initialization code to ->init() Viresh Kumar
2014-07-03  0:43   ` Stephen Boyd
2014-07-03  2:11     ` Viresh Kumar
2014-07-09 14:53   ` Santosh Shilimkar
2014-07-09 14:53     ` Santosh Shilimkar
2014-07-09 15:17     ` Viresh Kumar
2014-07-09 15:26       ` Santosh Shilimkar
2014-07-09 15:27         ` Viresh Kumar
2014-07-09 15:29           ` Santosh Shilimkar
2014-07-09 15:33             ` Viresh Kumar
2014-07-01 16:32 ` [PATCH 10/14] cpufreq: cpu0: try regulators with name "cpu-supply" Viresh Kumar
2014-07-01 16:32 ` [PATCH 11/14] cpufreq: cpu0: Make allocate_resources() work for any CPU Viresh Kumar
2014-07-01 16:32 ` [PATCH 12/14] cpufreq: cpu0: Extend support beyond CPU0 Viresh Kumar
2014-07-02  4:03   ` [PATCH V2 Resend " Viresh Kumar
2014-07-01 16:32 ` [PATCH 13/14] cpufreq: cpu0: rename driver and internals to 'cpufreq_generic' Viresh Kumar
2014-07-01 16:32 ` [PATCH 14/14] cpufreq: generic: set platform_{driver|device} '.name' to 'cpufreq-generic' Viresh Kumar
2014-07-02  4:12 ` [PATCH 00/14] cpufreq: cpu0: Extend support beyond CPU0, V2 Viresh Kumar
2014-07-03  1:24   ` Stephen Boyd
2014-07-03  2:44     ` Viresh Kumar [this message]
2014-07-03 22:16       ` Mike Turquette
2014-07-04  4:21         ` Viresh Kumar
2014-07-08  4:50           ` Viresh Kumar
2014-07-09 17:41             ` Stephen Boyd
2014-07-16 16:01             ` Viresh Kumar
2014-07-16 17:28               ` Thomas Petazzoni
2014-07-16 21:17                 ` Rafael J. Wysocki
2014-07-16 21:18               ` Rafael J. Wysocki
2014-07-17  0:28                 ` Viresh Kumar
2014-07-17  7:35                   ` Thomas Petazzoni
2014-07-17  7:41                     ` Viresh Kumar
2014-07-18  1:02                       ` Rafael J. Wysocki
2014-07-18  4:17                         ` Viresh Kumar
     [not found]                           ` <CAKohpomKzK8pMJs1gv+uXxhd17HtCQyfjSnVYw9KpGz6FwbgDA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-07-24 10:48                             ` Viresh Kumar
2014-07-24 10:48                               ` Viresh Kumar
2014-07-25 14:29                               ` Rob Herring
     [not found]                                 ` <CAL_JsqKqCeU0zs+rS1vxsOeh=Kuw_-gaVHtGU76Lb6TchCTytw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-07-25 14:34                                   ` Viresh Kumar
2014-07-25 14:34                                     ` Viresh Kumar
2014-07-25 15:41                                 ` Thomas Petazzoni

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