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From: Stephen Boyd <sboyd@codeaurora.org>
To: Michael Turquette <mturquette@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>,
	linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
	Russell King <linux@armlinux.org.uk>,
	Linus Walleij <linus.walleij@linaro.org>,
	Quentin Schulz <quentin.schulz@free-electrons.com>,
	Kevin Hilman <khilman@baylibre.com>,
	Maxime Ripard <maxime.ripard@free-electrons.com>
Subject: Re: [PATCH v5 00/10] clk: implement clock rate protection mechanism
Date: Thu, 21 Dec 2017 18:15:20 -0800	[thread overview]
Message-ID: <20171222021520.GO7997@codeaurora.org> (raw)
In-Reply-To: <151373031022.33554.13905466641279532222@resonance>

On 12/19, Michael Turquette wrote:
> Quoting Jerome Brunet (2017-12-01 13:51:50)
> > This Patchset is related the RFC [0] and the discussion around
> > CLK_SET_RATE_GATE available here [1]
> > 
> > This patchset introduce clock protection to the CCF core. This can then
> > be used for:
> > 
> > * Provide a way for a consumer to claim exclusivity over the rate control
> >   of a provider. Some clock consumers require that a clock rate must not
> >   deviate from its selected frequency. There can be several reasons for
> >   this, not least of which is that some hardware may not be able to
> >   handle or recover from a glitch caused by changing the clock rate while
> >   the hardware is in operation. For such HW, The ability to get exclusive
> >   control of a clock's rate, and release that exclusivity, could be seen
> >   as a fundamental clock rate control primitive. The exclusivity is not
> >   preemptible, so when claimed more than once, is rate is effectively
> >   locked.
> > 
> > * Provide a similar functionality to providers themselves, fixing
> >   CLK_SET_RATE_GATE flag (enforce clock gating along the tree). While
> >   there might still be a few platforms relying the broken implementation,
> >   tests done has shown this change to be pretty safe.
> 
> Applied to clk-protect-rate, with the exception that I did not apply
> "clk: fix CLK_SET_RATE_GATE with clock rate protection" as it breaks
> qcom clk code.
> 
> Stephen, do you plan to fix up the qcom clock code so that the
> SET_RATE_GATE improvement can go in?
> 

I started working on it a while back. Let's see if I can finish
it off this weekend.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

  parent reply	other threads:[~2017-12-22  2:15 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-01 21:51 Jerome Brunet
2017-12-01 21:51 ` [PATCH v5 01/10] clk: fix incorrect usage of ENOSYS Jerome Brunet
2017-12-01 21:51 ` [PATCH v5 02/10] clk: take the prepare lock out of clk_core_set_parent Jerome Brunet
2017-12-01 21:51 ` [PATCH v5 03/10] clk: add clk_core_set_phase_nolock function Jerome Brunet
2017-12-01 21:51 ` [PATCH v5 04/10] clk: rework calls to round and determine rate callbacks Jerome Brunet
2017-12-01 21:51 ` [PATCH v5 05/10] clk: use round rate to bail out early in set_rate Jerome Brunet
2017-12-01 21:51 ` [PATCH v5 06/10] clk: add clock protection mechanism to clk core Jerome Brunet
2017-12-01 21:51 ` [PATCH v5 07/10] clk: cosmetic changes to clk_summary debugfs entry Jerome Brunet
2017-12-01 21:51 ` [PATCH v5 08/10] clk: fix CLK_SET_RATE_GATE with clock rate protection Jerome Brunet
2018-03-30  8:20   ` Jerome Brunet
2017-12-01 21:51 ` [PATCH v5 09/10] clk: add clk_rate_exclusive api Jerome Brunet
2017-12-01 21:52 ` [PATCH v5 10/10] clk: fix set_rate_range when current rate is out of range Jerome Brunet
2017-12-20  0:38 ` [PATCH v5 00/10] clk: implement clock rate protection mechanism Michael Turquette
2017-12-20 17:45   ` Jerome Brunet
2017-12-22  2:15   ` Stephen Boyd [this message]
2018-01-29  9:22     ` Jerome Brunet
2018-02-01 17:43       ` Stephen Boyd
2018-02-02 12:50         ` Jerome Brunet
2018-04-23 18:21           ` Michael Turquette
2018-05-24 14:53             ` Jerome Brunet

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