From: Sowjanya Komatineni <skomatineni@nvidia.com>
To: Dmitry Osipenko <digetx@gmail.com>,
Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: <sboyd@kernel.org>, Michael Turquette <mturquette@baylibre.com>,
Joseph Lo <josephl@nvidia.com>, <thierry.reding@gmail.com>,
<jonathanh@nvidia.com>, <tglx@linutronix.de>,
<jason@lakedaemon.net>, <marc.zyngier@arm.com>,
<linus.walleij@linaro.org>, <stefan@agner.ch>,
<mark.rutland@arm.com>, <pgaikwad@nvidia.com>,
<linux-clk@vger.kernel.org>, <linux-gpio@vger.kernel.org>,
<jckuo@nvidia.com>, <talho@nvidia.com>,
<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<mperttunen@nvidia.com>, <spatra@nvidia.com>,
<robh+dt@kernel.org>, <devicetree@vger.kernel.org>
Subject: Re: [PATCH V5 11/18] clk: tegra210: Add support for Tegra210 clocks
Date: Thu, 18 Jul 2019 16:08:48 -0700 [thread overview]
Message-ID: <f664f161-9b6b-6446-e2f9-6373e654dfc3@nvidia.com> (raw)
In-Reply-To: <1c85cb35-ce7c-1dd1-f637-0c91b2b36db3@nvidia.com>
On 7/18/19 1:36 PM, Sowjanya Komatineni wrote:
>
> On 7/18/19 1:26 PM, Dmitry Osipenko wrote:
>> 18.07.2019 22:42, Peter De Schrijver пишет:
>>> On Thu, Jul 18, 2019 at 02:44:56AM +0300, Dmitry Osipenko wrote:
>>>>> dependencies I am referring are dfll_ref, dfll_soc, and DVFS
>>>>> peripheral
>>>>> clocks which need to be restored prior to DFLL reinit.
>>>> Okay, but that shouldn't be a problem if clock dependencies are set up
>>>> properly.
>>>>
>>>>>>> reverse list order during restore might not work as all other
>>>>>>> clocks are
>>>>>>> in proper order no with any ref clocks for plls getting restored
>>>>>>> prior
>>>>>>> to their clients
>>>>>> Why? The ref clocks should be registered first and be the roots
>>>>>> for PLLs
>>>>>> and the rest. If it's not currently the case, then this need to be
>>>>>> fixed. You need to ensure that each clock is modeled properly. If
>>>>>> some
>>>>>> child clock really depends on multiple parents, then the parents
>>>>>> need to
>>>>>> in the correct order or CCF need to be taught about such
>>>>>> multi-dependencies.
>>>>>>
>>>>>> If some required feature is missed, then you have to implement it
>>>>>> properly and for all, that's how things are done in upstream.
>>>>>> Sometimes
>>>>>> it's quite a lot of extra work that everyone are benefiting from in
>>>>>> the end.
>>>>>>
>>>>>> [snip]
>>>>> Yes, we should register ref/parents before their clients.
>>>>>
>>>>> cclk_g clk is registered last after all pll and peripheral clocks are
>>>>> registers during clock init.
>>>>>
>>>>> dfllCPU_out clk is registered later during dfll-fcpu driver probe and
>>>>> gets added to the clock list.
>>>>>
>>>>> Probably the issue seems to be not linking dfll_ref and dfll_soc
>>>>> dependencies for dfllCPU_out thru clock list.
>>>>>
>>>>> clk-dfll driver during dfll_init_clks gets ref_clk and soc_clk
>>>>> reference
>>>>> thru DT.
>>> The dfll does not have any parents. It has some clocks which are needed
>>> for the logic part of the dfll to function, but there's no parent clock
>>> as such unlike for peripheral clocks or PLLs where the parent is at
>>> least used as a reference. The I2C controller of the DFLL shares the
>>> lines with a normal I2C controller using some arbitration logic. That
>>> logic only works if the clock for the normal I2C controller is enabled.
>>> So you need probably 3 clocks enabled to initialize the dfll in that
>>> case. I don't think it makes sense to add complicated logic to the
>>> clock
>>> core to deal with this rather strange case. To me it makes more
>>> sense to
>>> use pmops and open code the sequence there.
>> It looks to me that dfllCPU is a PLL and dfll_ref is its reference
>> parent, while dfll_soc clocks the logic that dynamically reconfigures
>> dfllCPU in background. I see that PLLP is defined as a parent for
>> dfll_ref and dfll_soc in the code. Hence seems dfll_ref should be set as
>> a parent for dfllCPU, no?
>
> dfll_soc will not be restored by the time dfllCPU resume happens after
> dfll_ref.
>
> without dfll_soc, dfllCPU cannot be resumed either. So if we decide to
> use parent we should use dfll_soc.
>
>> Either way is good to me, given that DFLL will be disabled during
>> suspend. Resetting DFLL on DFLL's driver resume using PM ops should be
>> good. And then it also will be better to error out if DFLL is active
>> during suspend on the DFLL's driver suspend.
>
> Doing in dfll-fcpu pm_ops is much better as it happens right after all
> clocks are restored and unlike other clock enables, dfll need dfll
> controller programming as well and is actually registered in dfll-fcpu
> driver.
>
> With this, below is the sequence:
>
> CPUFreq suspend switches CPU to PLLP and disables dfll
>
> Will add dfll_suspend/resume in dfll-fcpu driver and in dfll suspend
> will check for dfll active and will error out suspend.
>
> dfll resume does dfll reinit.
>
> CPUFreq resume enables dfll and switches CPU to dfll.
>
>
> Will go with doing in dfll-fcpu pm_ops rather than parenting
> dfllCPU_OUT...
>
Does is make sense to return error EBUSY if dfll is not disabled by the
time dfll-fcpu suspend happens?
Or should I use ETIMEOUT?
next prev parent reply other threads:[~2019-07-18 23:08 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-28 2:12 [PATCH V5 00/18] SC7 entry and exit support for Tegra210 Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 01/18] irqchip: tegra: Do not disable COP IRQ during suspend Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 02/18] pinctrl: tegra: Add suspend and resume support Sowjanya Komatineni
2019-06-28 11:56 ` Dmitry Osipenko
2019-06-28 12:05 ` Dmitry Osipenko
2019-06-28 23:00 ` Sowjanya Komatineni
2019-06-29 12:38 ` Dmitry Osipenko
2019-06-29 15:40 ` Dmitry Osipenko
2019-06-29 15:46 ` Dmitry Osipenko
2019-06-29 15:58 ` Dmitry Osipenko
2019-06-29 16:28 ` Dmitry Osipenko
2019-07-04 7:31 ` Linus Walleij
2019-07-04 10:40 ` Dmitry Osipenko
2019-07-13 5:31 ` Sowjanya Komatineni
2019-07-14 21:41 ` Dmitry Osipenko
2019-07-13 5:48 ` Sowjanya Komatineni
2019-07-04 7:26 ` Linus Walleij
2019-06-28 2:12 ` [PATCH V5 03/18] clk: tegra: Save and restore divider rate Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 04/18] clk: tegra: pllout: Save and restore pllout context Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 05/18] clk: tegra: pll: Save and restore pll context Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 06/18] clk: tegra: Save and restore CPU and System clocks context Sowjanya Komatineni
2019-06-29 13:33 ` Dmitry Osipenko
2019-06-29 15:26 ` Dmitry Osipenko
2019-06-28 2:12 ` [PATCH V5 07/18] clk: tegra: Support for saving and restoring OSC context Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 08/18] clk: tegra: Add suspend resume support for DFLL Sowjanya Komatineni
2019-06-29 13:28 ` Dmitry Osipenko
2019-06-29 21:45 ` Dmitry Osipenko
2019-06-28 2:12 ` [PATCH V5 09/18] clk: tegra: Add save and restore context support for peripheral clocks Sowjanya Komatineni
2019-06-29 13:17 ` Dmitry Osipenko
2019-06-28 2:12 ` [PATCH V5 10/18] clk: tegra210: Use fence_udelay during PLLU init Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 11/18] clk: tegra210: Add support for Tegra210 clocks Sowjanya Komatineni
2019-06-29 13:14 ` Dmitry Osipenko
2019-06-29 15:10 ` Dmitry Osipenko
2019-07-13 5:54 ` Sowjanya Komatineni
2019-07-14 21:41 ` Dmitry Osipenko
2019-07-16 0:35 ` Sowjanya Komatineni
2019-07-16 3:00 ` Sowjanya Komatineni
2019-07-16 3:41 ` Sowjanya Komatineni
2019-07-16 3:50 ` Dmitry Osipenko
2019-07-16 4:37 ` Sowjanya Komatineni
2019-07-16 5:37 ` Dmitry Osipenko
2019-07-16 6:20 ` Dmitry Osipenko
2019-07-16 6:35 ` Sowjanya Komatineni
2019-07-16 7:24 ` Joseph Lo
2019-07-16 8:06 ` Peter De Schrijver
2019-07-16 15:00 ` Dmitry Osipenko
2019-07-16 16:50 ` Sowjanya Komatineni
2019-07-16 18:19 ` Sowjanya Komatineni
2019-07-16 18:25 ` Dmitry Osipenko
2019-07-16 18:30 ` Sowjanya Komatineni
2019-07-16 18:43 ` Dmitry Osipenko
2019-07-16 19:26 ` Sowjanya Komatineni
2019-07-16 20:47 ` Dmitry Osipenko
2019-07-16 21:12 ` Sowjanya Komatineni
2019-07-16 21:21 ` Dmitry Osipenko
2019-07-16 21:35 ` Sowjanya Komatineni
2019-07-16 22:00 ` Dmitry Osipenko
2019-07-16 22:06 ` Sowjanya Komatineni
2019-07-17 2:18 ` Sowjanya Komatineni
2019-07-17 2:35 ` Sowjanya Komatineni
2019-07-17 4:11 ` Dmitry Osipenko
[not found] ` <77df234f-aa40-0319-a593-f1f19f0f1c2a@nvidia.com>
2019-07-17 5:42 ` Dmitry Osipenko
2019-07-17 5:55 ` Sowjanya Komatineni
2019-07-17 6:33 ` Dmitry Osipenko
2019-07-17 6:36 ` Sowjanya Komatineni
2019-07-17 15:17 ` Dmitry Osipenko
2019-07-17 17:29 ` Sowjanya Komatineni
2019-07-17 18:32 ` Dmitry Osipenko
2019-07-17 18:51 ` Sowjanya Komatineni
2019-07-17 18:54 ` Sowjanya Komatineni
2019-07-17 19:43 ` Dmitry Osipenko
2019-07-17 20:01 ` Sowjanya Komatineni
2019-07-17 20:11 ` Sowjanya Komatineni
2019-07-17 21:29 ` Sowjanya Komatineni
2019-07-17 21:30 ` Dmitry Osipenko
2019-07-17 21:51 ` Sowjanya Komatineni
2019-07-17 21:57 ` Sowjanya Komatineni
2019-07-17 22:48 ` Dmitry Osipenko
2019-07-17 23:36 ` Sowjanya Komatineni
2019-07-17 23:44 ` Dmitry Osipenko
2019-07-18 0:25 ` Sowjanya Komatineni
2019-07-18 1:15 ` Sowjanya Komatineni
2019-07-18 16:34 ` Dmitry Osipenko
2019-07-18 17:22 ` Sowjanya Komatineni
2019-07-18 17:41 ` Sowjanya Komatineni
2019-07-18 18:29 ` Sowjanya Komatineni
2019-07-18 19:11 ` Sowjanya Komatineni
2019-07-18 19:42 ` Peter De Schrijver
2019-07-18 20:26 ` Dmitry Osipenko
2019-07-18 20:36 ` Sowjanya Komatineni
2019-07-18 22:52 ` Dmitry Osipenko
2019-07-18 23:08 ` Sowjanya Komatineni [this message]
2019-07-18 23:52 ` Dmitry Osipenko
2019-07-17 3:54 ` Dmitry Osipenko
2019-07-17 4:01 ` Sowjanya Komatineni
2019-07-18 19:18 ` Peter De Schrijver
2019-07-18 19:24 ` Sowjanya Komatineni
2019-07-18 20:11 ` Dmitry Osipenko
2019-07-18 20:32 ` Dmitry Osipenko
2019-07-18 19:15 ` Peter De Schrijver
2019-06-29 15:13 ` Dmitry Osipenko
2019-06-28 2:12 ` [PATCH V5 12/18] soc/tegra: pmc: Allow support for more tegra wake Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 13/18] soc/tegra: pmc: Add pmc wake support for tegra210 Sowjanya Komatineni
2019-06-29 13:11 ` Dmitry Osipenko
2019-06-28 2:12 ` [PATCH V5 14/18] arm64: tegra: Enable wake from deep sleep on RTC alarm Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 15/18] soc/tegra: pmc: Configure core power request polarity Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 16/18] soc/tegra: pmc: Configure deep sleep control settings Sowjanya Komatineni
2019-06-29 13:00 ` Dmitry Osipenko
2019-06-29 13:02 ` Dmitry Osipenko
2019-06-28 2:12 ` [PATCH V5 17/18] arm64: dts: tegra210-p2180: Jetson TX1 SC7 timings Sowjanya Komatineni
2019-06-28 2:12 ` [PATCH V5 18/18] arm64: dts: tegra210-p3450: Jetson nano " Sowjanya Komatineni
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