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Message-ID: <CAJ0PZbSXzkvkOjWw66k5ZrtksQxiF0HwcFZ4jHKs9=4XodszVg@mail.gmail.com>
Date: Mon, 12 Mar 2012 11:12:55 +0900
From: MyungJoo Ham <myungjoo.ham@...sung.com>
To: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
Kyungmin Park <kyungmin.park@...sung.com>,
Kevin Hilman <khilman@...com>,
Mike Turquette <mturquette@...com>
Subject: Re: [PATCH] PM / devfreq: add relation of recommended frequency.
2012/3/11 Rafael J. Wysocki <rjw@...k.pl>:
> On Wednesday, March 07, 2012, MyungJoo Ham wrote:
>> The semantics of "target frequency" given to devfreq driver from
>> devfreq framework has always been interpretted as "at least" or GLB
>> (greatest lower bound). However, the framework might want the
>> device driver to limit its max frequency (LUB: least upper bound),
>> especially if it is given by thermal framework (it's too hot).
>>
>> Thus, the target fuction should have another parameter to express
>> whether the framework wants GLB or LUB. And, the additional parameter,
>> "u32 options", does it.
>>
>> With the update, devfreq_recommended_opp() is also updated.
>>
>> Signed-off-by: MyungJoo Ham <myungjoo.ham@...sung.com>
>> Signed-off-by: Kyungmin Park <kyungmin.park@...sung.com>
>
> This one looks good.
>
> Do you want me to take it as a patch, or to pull it from your tree?
>
> Rafael
Hello Rafael,
Please pull it from the tree
(http://git.infradead.org/users/kmpark/linux-samsung/shortlog/refs/heads/devfreq-for-next)
as the change log has been corrected.
git://git.infradead.org/users/kmpark/linux-samsung devfreq-for-next
Thank you.
Cheers!
MyungJoo.
>
>
>> ---
>> Changes from v1
>> - Style update.
>> ---
>> drivers/devfreq/devfreq.c | 41 ++++++++++++++++++++++++++++++-----------
>> drivers/devfreq/exynos4_bus.c | 14 ++++++++++----
>> include/linux/devfreq.h | 16 +++++++++++++---
>> 3 files changed, 53 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 0b49f59..13794d1 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -84,6 +84,7 @@ int update_devfreq(struct devfreq *devfreq)
>> {
>> unsigned long freq;
>> int err = 0;
>> + u32 flags = 0;
>>
>> if (!mutex_is_locked(&devfreq->lock)) {
>> WARN(true, "devfreq->lock must be locked by the caller.\n");
>> @@ -104,18 +105,20 @@ int update_devfreq(struct devfreq *devfreq)
>> * qos_min_freq
>> */
>>
>> - if (devfreq->qos_min_freq && freq < devfreq->qos_min_freq)
>> + if (devfreq->qos_min_freq && freq < devfreq->qos_min_freq) {
>> freq = devfreq->qos_min_freq;
>> - if (devfreq->max_freq && freq > devfreq->max_freq)
>> + flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
>> + }
>> + if (devfreq->max_freq && freq > devfreq->max_freq) {
>> freq = devfreq->max_freq;
>> - if (devfreq->min_freq && freq < devfreq->min_freq)
>> + flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
>> + }
>> + if (devfreq->min_freq && freq < devfreq->min_freq) {
>> freq = devfreq->min_freq;
>> + flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
>> + }
>>
>> - /*
>> - * TODO in the devfreq-next:
>> - * add relation or use rance (freq_min, freq_max)
>> - */
>> - err = devfreq->profile->target(devfreq->dev.parent, &freq);
>> + err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
>> if (err)
>> return err;
>>
>> @@ -773,14 +776,30 @@ module_exit(devfreq_exit);
>> * freq value given to target callback.
>> * @dev The devfreq user device. (parent of devfreq)
>> * @freq The frequency given to target function
>> + * @flags Flags handed from devfreq framework.
>> *
>> */
>> -struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq)
>> +struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq,
>> + u32 flags)
>> {
>> - struct opp *opp = opp_find_freq_ceil(dev, freq);
>> + struct opp *opp;
>>
>> - if (opp == ERR_PTR(-ENODEV))
>> + if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
>> + /* The freq is an upper bound. opp should be lower */
>> opp = opp_find_freq_floor(dev, freq);
>> +
>> + /* If not available, use the closest opp */
>> + if (opp == ERR_PTR(-ENODEV))
>> + opp = opp_find_freq_ceil(dev, freq);
>> + } else {
>> + /* The freq is an lower bound. opp should be higher */
>> + opp = opp_find_freq_ceil(dev, freq);
>> +
>> + /* If not available, use the closest opp */
>> + if (opp == ERR_PTR(-ENODEV))
>> + opp = opp_find_freq_floor(dev, freq);
>> + }
>> +
>> return opp;
>> }
>>
>> diff --git a/drivers/devfreq/exynos4_bus.c b/drivers/devfreq/exynos4_bus.c
>> index 590d686..1a361e9 100644
>> --- a/drivers/devfreq/exynos4_bus.c
>> +++ b/drivers/devfreq/exynos4_bus.c
>> @@ -619,13 +619,19 @@ static int exynos4_bus_setvolt(struct busfreq_data *data, struct opp *opp,
>> return err;
>> }
>>
>> -static int exynos4_bus_target(struct device *dev, unsigned long *_freq)
>> +static int exynos4_bus_target(struct device *dev, unsigned long *_freq,
>> + u32 flags)
>> {
>> int err = 0;
>> - struct busfreq_data *data = dev_get_drvdata(dev);
>> - struct opp *opp = devfreq_recommended_opp(dev, _freq);
>> - unsigned long old_freq = opp_get_freq(data->curr_opp);
>> + struct platform_device *pdev = container_of(dev, struct platform_device,
>> + dev);
>> + struct busfreq_data *data = platform_get_drvdata(pdev);
>> + struct opp *opp = devfreq_recommended_opp(dev, _freq, flags);
>> unsigned long freq = opp_get_freq(opp);
>> + unsigned long old_freq = opp_get_freq(data->curr_opp);
>> +
>> + if (IS_ERR(opp))
>> + return PTR_ERR(opp);
>>
>> if (old_freq == freq)
>> return 0;
>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>> index f27d511..85d4b0f 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -59,6 +59,14 @@ struct devfreq_pm_qos_table {
>> s32 qos_value;
>> };
>>
>> +/*
>> + * The resulting frequency should be at most this. (this bound is the
>> + * least upper bound; thus, the resulting freq should be lower or same)
>> + * If the flag is not set, the resulting frequency should be at most the
>> + * bound (greatest lower bound)
>> + */
>> +#define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
>> +
>> /**
>> * struct devfreq_dev_profile - Devfreq's user device profile
>> * @initial_freq The operating frequency when devfreq_add_device() is
>> @@ -74,6 +82,8 @@ struct devfreq_pm_qos_table {
>> * higher than any operable frequency, set maximum.
>> * Before returning, target function should set
>> * freq at the current frequency.
>> + * The "flags" parameter's possible values are
>> + * explained above with "DEVFREQ_FLAG_*" macros.
>> * @get_dev_status The device should provide the current performance
>> * status to devfreq, which is used by governors.
>> * @exit An optional callback that is called when devfreq
>> @@ -92,7 +102,7 @@ struct devfreq_dev_profile {
>> int qos_type;
>> struct devfreq_pm_qos_table *qos_list;
>>
>> - int (*target)(struct device *dev, unsigned long *freq);
>> + int (*target)(struct device *dev, unsigned long *freq, u32 flags);
>> int (*get_dev_status)(struct device *dev,
>> struct devfreq_dev_status *stat);
>> void (*exit)(struct device *dev);
>> @@ -198,7 +208,7 @@ extern int devfreq_remove_device(struct devfreq *devfreq);
>>
>> /* Helper functions for devfreq user device driver with OPP. */
>> extern struct opp *devfreq_recommended_opp(struct device *dev,
>> - unsigned long *freq);
>> + unsigned long *freq, u32 flags);
>> extern int devfreq_register_opp_notifier(struct device *dev,
>> struct devfreq *devfreq);
>> extern int devfreq_unregister_opp_notifier(struct device *dev,
>> @@ -253,7 +263,7 @@ static int devfreq_remove_device(struct devfreq *devfreq)
>> }
>>
>> static struct opp *devfreq_recommended_opp(struct device *dev,
>> - unsigned long *freq)
>> + unsigned long *freq, u32 flags)
>> {
>> return -EINVAL;
>> }
>>
>
--
MyungJoo Ham, Ph.D.
Mobile Software Platform Lab, DMC Business, Samsung Electronics
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