From: Stephen Boyd <sboyd@kernel.org>
To: agross@kernel.org, jorge.ramirez-ortiz@linaro.org,
mturquette@baylibre.com
Cc: bjorn.andersson@linaro.org, niklas.cassel@linaro.org,
linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/5] clk: qcom: hfpll: CLK_IGNORE_UNUSED
Date: Mon, 09 Sep 2019 03:23:10 -0700 [thread overview]
Message-ID: <20190909102311.1552C2089F@mail.kernel.org> (raw)
In-Reply-To: <20190826164510.6425-5-jorge.ramirez-ortiz@linaro.org>
Quoting Jorge Ramirez-Ortiz (2019-08-26 09:45:10)
> When COMMON_CLK_DISABLED_UNUSED is set, in an effort to save power and
> to keep the software model of the clock in line with reality, the
> framework transverses the clock tree and disables those clocks that
> were enabled by the firmware but have not been enabled by any device
> driver.
>
> If CPUFREQ is enabled, early during the system boot, it might attempt
> to change the CPU frequency ("set_rate"). If the HFPLL is selected as
> a provider, it will then change the rate for this clock.
>
> As boot continues, clk_disable_unused_subtree will run. Since it wont
> find a valid counter (enable_count) for a clock that is actually
> enabled it will attempt to disable it which will cause the CPU to
> stop. Notice that in this driver, calls to check whether the clock is
> enabled are routed via the is_enabled callback which queries the
> hardware.
>
> The following commit, rather than marking the clock critical and
> forcing the clock to be always enabled, addresses the above scenario
> making sure the clock is not disabled but it continues to rely on the
> firmware to enable the clock.
>
> Co-developed-by: Niklas Cassel <niklas.cassel@linaro.org>
> Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
Also this one. Seems fine to merge immediately vs the ones that do some
DT trickery.
next prev parent reply other threads:[~2019-09-09 10:23 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-26 16:45 [PATCH 1/5] clk: qcom: gcc: limit GPLL0_AO_OUT operating frequency Jorge Ramirez-Ortiz
2019-08-26 16:45 ` [PATCH 2/5] clk: qcom: apcs-msm8916: get parent clock names from DT Jorge Ramirez-Ortiz
2019-09-09 10:21 ` Stephen Boyd
2019-09-09 14:17 ` Jorge Ramirez-Ortiz, Linaro
2019-09-09 16:17 ` Stephen Boyd
2019-09-09 16:54 ` Jorge Ramirez-Ortiz, Linaro
2019-09-10 9:14 ` Stephen Boyd
2019-09-10 9:34 ` Jorge Ramirez
2019-09-10 9:40 ` Jorge Ramirez
2019-09-10 10:20 ` Stephen Boyd
2019-09-09 10:23 ` Stephen Boyd
2019-08-26 16:45 ` [PATCH 3/5] clk: qcom: hfpll: " Jorge Ramirez-Ortiz
2019-09-09 10:22 ` Stephen Boyd
2019-08-26 16:45 ` [PATCH 4/5] clk: qcom: hfpll: register as clock provider Jorge Ramirez-Ortiz
2019-09-09 10:22 ` Stephen Boyd
2019-08-26 16:45 ` [PATCH 5/5] clk: qcom: hfpll: CLK_IGNORE_UNUSED Jorge Ramirez-Ortiz
2019-09-09 10:23 ` Stephen Boyd [this message]
2019-09-05 7:30 ` [PATCH 1/5] clk: qcom: gcc: limit GPLL0_AO_OUT operating frequency Jorge Ramirez
2019-09-09 10:05 ` Stephen Boyd
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