From: Dmitry Osipenko <digetx@gmail.com>
To: Chanwoo Choi <cw00.choi@samsung.com>,
Thierry Reding <thierry.reding@gmail.com>,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 02/24] PM / devfreq: tegra30: Keep interrupt disabled while governor is stopped
Date: Wed, 17 Jul 2019 19:44:11 +0300 [thread overview]
Message-ID: <00dfcd92-a41a-11c0-b8b2-1cdc68048aa9@gmail.com> (raw)
In-Reply-To: <ca339b7f-1141-4c68-1c07-2ac818422bbc@samsung.com>
17.07.2019 9:37, Chanwoo Choi пишет:
> On 19. 7. 16. 오후 10:03, Dmitry Osipenko wrote:
>> 16.07.2019 14:47, Chanwoo Choi пишет:
>>> On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
>>>> There is no real need to keep interrupt always-enabled, will be nicer
>>>> to keep it disabled while governor is inactive.
>>>>
>>>> Suggested-by: Thierry Reding <thierry.reding@gmail.com>
>>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>>>> ---
>>>> drivers/devfreq/tegra30-devfreq.c | 43 ++++++++++++++++---------------
>>>> 1 file changed, 22 insertions(+), 21 deletions(-)
>>>>
>>>> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
>>>> index a27300f40b0b..5e2b133babdd 100644
>>>> --- a/drivers/devfreq/tegra30-devfreq.c
>>>> +++ b/drivers/devfreq/tegra30-devfreq.c
>>>> @@ -11,6 +11,7 @@
>>>> #include <linux/devfreq.h>
>>>> #include <linux/interrupt.h>
>>>> #include <linux/io.h>
>>>> +#include <linux/irq.h>
>>>> #include <linux/module.h>
>>>> #include <linux/mod_devicetable.h>
>>>> #include <linux/platform_device.h>
>>>> @@ -416,8 +417,6 @@ static void tegra_actmon_start(struct tegra_devfreq *tegra)
>>>> {
>>>> unsigned int i;
>>>>
>>>> - disable_irq(tegra->irq);
>>>> -
>>>> actmon_writel(tegra, ACTMON_SAMPLING_PERIOD - 1,
>>>> ACTMON_GLB_PERIOD_CTRL);
>>>>
>>>> @@ -442,8 +441,6 @@ static void tegra_actmon_stop(struct tegra_devfreq *tegra)
>>>> }
>>>>
>>>> actmon_write_barrier(tegra);
>>>> -
>>>> - enable_irq(tegra->irq);
>>>> }
>>>>
>>>> static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
>>>> @@ -552,6 +549,12 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
>>>> {
>>>> struct tegra_devfreq *tegra = dev_get_drvdata(devfreq->dev.parent);
>>>>
>>>> + /*
>>>> + * Couple device with the governor early as it is needed at
>>>> + * the moment of governor's start (used by ISR).
>>>> + */
>>>> + tegra->devfreq = devfreq;
>>>
>>> I'm not sure it is necessary. Almost devfreq device get
>>> the devfreq instance on probe timing through devfreq_add_device directly.
>>
>> This is necessary because this assignment is for the "governor" and not
>> the "device". Governor is started during of devfreq_add_device(), hence
>> there is no better way to assign device to the driver's governor.
>
> OK. I understand.
>
> But, I have a question. Is it working before this patch?
> How can you test it on that tegra->devfreq is NULL?
It was working before this patch because previously interrupt was
requested *after* devfreq_add_device(), now the IRQ requesting happens
*before* devfreq_add_device() and enabling *during of*. If interrupt
fires before the assignment happened, then ISR gets a NULL deference and
this is easily reproducible.
Please note that 'tegra->devfreq' is used only by the ISR and onward, in
the further patches of this series the usage is extended by the cpufreq
notifier.
>>
>>>> +
>>>> switch (event) {
>>>> case DEVFREQ_GOV_START:
>>>> devfreq_monitor_start(devfreq);
>>>> @@ -586,10 +589,11 @@ static struct devfreq_governor tegra_devfreq_governor = {
>>>>
>>>> static int tegra_devfreq_probe(struct platform_device *pdev)
>>>> {
>>>> - struct tegra_devfreq *tegra;
>>>> struct tegra_devfreq_device *dev;
>>>> - unsigned int i;
>>>> + struct tegra_devfreq *tegra;
>>>> + struct devfreq *devfreq;
>>>> unsigned long rate;
>>>> + unsigned int i;
>>>> int err;
>>>>
>>>> tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
>>>> @@ -625,6 +629,16 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
>>>> }
>>>> tegra->irq = err;
>>>>
>>>> + irq_set_status_flags(tegra->irq, IRQ_NOAUTOEN);
>>>> +
>>>> + err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
>>>> + actmon_thread_isr, IRQF_ONESHOT,
>>>> + "tegra-devfreq", tegra);
>>>> + if (err) {
>>>> + dev_err(&pdev->dev, "Interrupt request failed: %d\n", err);
>>>> + return err;
>>>> + }
>>>> +
>>>> reset_control_assert(tegra->reset);
>>>>
>>>> err = clk_prepare_enable(tegra->clock);
>>>> @@ -672,28 +686,15 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
>>>> }
>>>>
>>>> tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
>>>> - tegra->devfreq = devfreq_add_device(&pdev->dev,
>>>> - &tegra_devfreq_profile,
>>>> - "tegra_actmon",
>>>> - NULL);
>>>> + devfreq = devfreq_add_device(&pdev->dev, &tegra_devfreq_profile,
>>>> + "tegra_actmon", NULL);
>>>> if (IS_ERR(tegra->devfreq)) {
>>>
>>> Have to check 'devfreq' instead of 'tegra->devfreq'.
>>> Did you test it? It might be failed because 'tegra->devfreq is NULL.
>>
>> That's a good catch! Thank you very much.
>>
>>>> err = PTR_ERR(tegra->devfreq);
>>>
>>> ditto.
>>
>> Ok
next prev parent reply other threads:[~2019-07-17 16:44 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-07 22:32 [PATCH v4 00/24] More improvements for Tegra30 devfreq driver Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 01/24] PM / devfreq: tegra30: Change irq type to unsigned int Dmitry Osipenko
2019-07-16 11:35 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 02/24] PM / devfreq: tegra30: Keep interrupt disabled while governor is stopped Dmitry Osipenko
2019-07-16 11:47 ` Chanwoo Choi
2019-07-16 13:03 ` Dmitry Osipenko
2019-07-17 6:37 ` Chanwoo Choi
2019-07-17 16:44 ` Dmitry Osipenko [this message]
2019-07-07 22:32 ` [PATCH v4 03/24] PM / devfreq: tegra30: Handle possible round-rate error Dmitry Osipenko
2019-07-16 11:50 ` Chanwoo Choi
2019-07-16 13:09 ` Dmitry Osipenko
2019-07-17 6:38 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 04/24] PM / devfreq: tegra30: Drop write-barrier Dmitry Osipenko
2019-07-16 11:51 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 05/24] PM / devfreq: tegra30: Set up watermarks properly Dmitry Osipenko
2019-07-18 10:17 ` Chanwoo Choi
2019-07-19 0:00 ` Dmitry Osipenko
2019-07-19 1:31 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 06/24] PM / devfreq: tegra30: Tune up boosting thresholds Dmitry Osipenko
2019-07-16 11:55 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 07/24] PM / devfreq: tegra30: Use CPUFreq notifier Dmitry Osipenko
2019-07-16 12:08 ` Chanwoo Choi
2019-07-16 13:18 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 08/24] PM / devfreq: tegra30: Move clk-notifier's registration to governor's start Dmitry Osipenko
2019-07-16 12:11 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 09/24] PM / devfreq: tegra30: Reset boosting on startup Dmitry Osipenko
2019-07-16 12:13 ` Chanwoo Choi
2019-07-16 13:19 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 10/24] PM / devfreq: tegra30: Don't enable consecutive-down interrupt " Dmitry Osipenko
2019-07-16 12:17 ` Chanwoo Choi
2019-07-16 15:17 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 11/24] PM / devfreq: tegra30: Add debug messages Dmitry Osipenko
2019-07-16 12:23 ` Chanwoo Choi
2019-07-16 13:26 ` Dmitry Osipenko
2019-07-17 6:45 ` Chanwoo Choi
2019-07-17 15:46 ` Dmitry Osipenko
2019-07-18 9:07 ` Chanwoo Choi
2019-07-19 1:13 ` Dmitry Osipenko
2019-07-19 1:22 ` Chanwoo Choi
2019-07-19 17:10 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 12/24] PM / devfreq: tegra30: Inline all one-line functions Dmitry Osipenko
2019-07-16 12:26 ` Chanwoo Choi
2019-07-16 13:35 ` Dmitry Osipenko
2019-07-18 9:09 ` Chanwoo Choi
2019-07-19 1:22 ` Dmitry Osipenko
2019-07-19 1:24 ` Chanwoo Choi
2019-07-19 1:27 ` Chanwoo Choi
2019-07-19 2:14 ` Dmitry Osipenko
2019-07-19 6:01 ` Chanwoo Choi
2019-07-19 16:52 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 13/24] PM / devfreq: tegra30: Constify structs Dmitry Osipenko
2019-07-16 12:26 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 14/24] PM / devfreq: tegra30: Ensure that target freq won't overflow Dmitry Osipenko
2019-07-16 12:30 ` Chanwoo Choi
2019-07-16 13:59 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 15/24] PM / devfreq: tegra30: Fix integer overflow on CPU's freq max out Dmitry Osipenko
2019-07-16 12:32 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 16/24] PM / devfreq: tegra30: Use kHz units uniformly in the code Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 17/24] PM / devfreq: tegra30: Use tracepoints for debugging Dmitry Osipenko
2019-07-18 9:47 ` Chanwoo Choi
2019-07-19 0:49 ` Dmitry Osipenko
2019-07-19 1:01 ` Chanwoo Choi
2019-07-19 1:50 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 18/24] PM / devfreq: tegra30: Optimize CPUFreq notifier Dmitry Osipenko
2019-07-18 9:48 ` Chanwoo Choi
2019-07-19 0:42 ` Dmitry Osipenko
2019-07-19 1:09 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 19/24] PM / devfreq: tegra30: Optimize upper consecutive watermark selection Dmitry Osipenko
2019-07-18 9:51 ` Chanwoo Choi
2019-07-19 0:40 ` Dmitry Osipenko
2019-07-19 1:15 ` Chanwoo Choi
2019-07-19 1:17 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 20/24] PM / devfreq: tegra30: Optimize upper average " Dmitry Osipenko
2019-07-19 1:36 ` Chanwoo Choi
2019-07-19 1:59 ` Dmitry Osipenko
2019-07-19 2:06 ` Chanwoo Choi
2019-07-19 2:21 ` Dmitry Osipenko
2019-07-19 6:09 ` Chanwoo Choi
2019-07-19 6:11 ` Chanwoo Choi
2019-07-19 17:52 ` Dmitry Osipenko
2019-07-24 11:17 ` Chanwoo Choi
2019-07-24 11:19 ` Chanwoo Choi
2019-07-07 22:33 ` [PATCH v4 21/24] PM / devfreq: tegra30: Synchronize average count on target's update Dmitry Osipenko
2019-07-18 10:15 ` Chanwoo Choi
2019-07-19 0:31 ` Dmitry Osipenko
2019-07-19 1:40 ` Chanwoo Choi
2019-07-19 16:46 ` Dmitry Osipenko
2019-07-07 22:33 ` [PATCH v4 22/24] PM / devfreq: tegra30: Include appropriate header Dmitry Osipenko
2019-07-18 9:58 ` Chanwoo Choi
2019-07-19 0:34 ` Dmitry Osipenko
2019-07-07 22:33 ` [PATCH v4 23/24] PM / devfreq: tegra30: Increase sampling period to 16ms Dmitry Osipenko
2019-07-18 10:00 ` Chanwoo Choi
2019-07-07 22:33 ` [PATCH v4 24/24] PM / devfreq: tegra20/30: Add Dmitry as a maintainer Dmitry Osipenko
2019-07-18 9:56 ` Chanwoo Choi
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