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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 07/24] PM / devfreq: tegra30: Use CPUFreq notifier
Date: Tue, 16 Jul 2019 16:18:02 +0300
Message-ID: <23176828-02b8-7781-54f1-4dbf28e3098b@gmail.com> (raw)
In-Reply-To: <c94da786-05b4-1604-d208-f73f32ea937d@samsung.com>

16.07.2019 15:08, Chanwoo Choi пишет:
> On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
>> The CPU's client need to take into account that CPUFreq may change
>> while memory activity not, staying high. Thus an appropriate frequency
>> notifier should be used in addition to the clk-notifier.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>>  drivers/devfreq/tegra30-devfreq.c | 105 +++++++++++++++++++++++++-----
>>  1 file changed, 88 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
>> index 2bf65409ddd8..48a799fa5f63 100644
>> --- a/drivers/devfreq/tegra30-devfreq.c
>> +++ b/drivers/devfreq/tegra30-devfreq.c
>> @@ -17,6 +17,7 @@
>>  #include <linux/platform_device.h>
>>  #include <linux/pm_opp.h>
>>  #include <linux/reset.h>
>> +#include <linux/workqueue.h>
>>  
>>  #include "governor.h"
>>  
>> @@ -154,7 +155,10 @@ struct tegra_devfreq {
>>  
>>  	struct clk		*emc_clock;
>>  	unsigned long		max_freq;
>> -	struct notifier_block	rate_change_nb;
>> +	struct notifier_block	clk_rate_change_nb;
>> +
>> +	struct work_struct	update_work;
> 
> nitpick.
> I think 'update_work' is not clear to indicate the work
> for changing the clock according to the cpu clock change.
> You better to change the name for more clearly.

Okay, I'll rename it to 'cpufreq_update_work' or something like that.

>> +	struct notifier_block	cpu_rate_change_nb;
>>  
>>  	struct tegra_devfreq_device devices[ARRAY_SIZE(actmon_device_configs)];
>>  
>> @@ -456,8 +460,8 @@ static irqreturn_t actmon_thread_isr(int irq, void *data)
>>  	return handled ? IRQ_HANDLED : IRQ_NONE;
>>  }
>>  
>> -static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
>> -				       unsigned long action, void *ptr)
>> +static int tegra_actmon_clk_notify_cb(struct notifier_block *nb,
>> +				      unsigned long action, void *ptr)
>>  {
>>  	struct clk_notifier_data *data = ptr;
>>  	struct tegra_devfreq_device *dev;
>> @@ -467,7 +471,7 @@ static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
>>  	if (action != POST_RATE_CHANGE)
>>  		return NOTIFY_OK;
>>  
>> -	tegra = container_of(nb, struct tegra_devfreq, rate_change_nb);
>> +	tegra = container_of(nb, struct tegra_devfreq, clk_rate_change_nb);
>>  
>>  	/*
>>  	 * EMC rate could change due to three reasons:
>> @@ -496,6 +500,37 @@ static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
>>  	return NOTIFY_OK;
>>  }
>>  
>> +static void tegra_actmon_delayed_update(struct work_struct *work)
>> +{
>> +	struct tegra_devfreq *tegra = container_of(work, struct tegra_devfreq,
>> +						   update_work);
>> +
>> +	mutex_lock(&tegra->devfreq->lock);
>> +	update_devfreq(tegra->devfreq);
>> +	mutex_unlock(&tegra->devfreq->lock);
>> +}
>> +
>> +static int tegra_actmon_cpu_notify_cb(struct notifier_block *nb,
>> +				      unsigned long action, void *ptr)
>> +{
>> +	struct tegra_devfreq *tegra;
>> +
>> +	if (action != CPUFREQ_POSTCHANGE)
>> +		return NOTIFY_OK;
>> +
>> +	tegra = container_of(nb, struct tegra_devfreq, cpu_rate_change_nb);
> 
> nitpick. Better to check whether 'tegra' is NULL or not.

It can't be NULL, unless 'nb' is NULL and even in that case
container_of() will cause kernel crash. Hence it's absolutely
unnecessary to check for NULL here.

>> +
>> +	/*
>> +	 * CPUFreq driver should support CPUFREQ_ASYNC_NOTIFICATION in order
>> +	 * to allow asynchronous notifications. This means we can't block
>> +	 * here for too long, otherwise CPUFreq's core will complain with a
>> +	 * warning splat.
>> +	 */
>> +	schedule_work(&tegra->update_work);
>> +
>> +	return NOTIFY_OK;
>> +}
>> +
>>  static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
>>  					  struct tegra_devfreq_device *dev)
>>  {
>> @@ -527,9 +562,16 @@ static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
>>  	device_writel(dev, val, ACTMON_DEV_CTRL);
>>  }
>>  
>> -static void tegra_actmon_start(struct tegra_devfreq *tegra)
>> +static void tegra_actmon_stop_device(struct tegra_devfreq_device *dev)
>> +{
>> +	device_writel(dev, 0x00000000, ACTMON_DEV_CTRL);
> 
> Better to define the constant definition of 0x00000000
> in order to explain the correct meaning.
> 
> For example,
> #define ACTMON_DEV_RESET	0x00000000

Okay.

  reply index

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
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 [this message]
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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