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Message-ID: <CAJ0PZbRfRR-aT-JDUdwQ5bi_TVKpJU4u8-qAKMK1nCwHSgAQoQ@mail.gmail.com>
Date: Fri, 9 Mar 2012 16:09:58 +0900
From: MyungJoo Ham <myungjoo.ham@...sung.com>
To: "Turquette, Mike" <mturquette@...com>
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
Kyungmin Park <kyungmin.park@...sung.com>,
"Rafael J. Wysocki" <rjw@...k.pl>, Kevin Hilman <khilman@...com>
Subject: Re: [PATCH] PM / devfreq: add relation of recommended frequency.
On Thu, Mar 8, 2012 at 2:45 AM, Turquette, Mike <mturquette@...com> wrote:
> On Thu, Feb 9, 2012 at 11:19 PM, MyungJoo Ham <myungjoo.ham@...sung.com> 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.
>
> Nitpick: changelog still refers to "options" but code reads "flags".
>
> Regards,
> Mike
>
Thanks. That is updated in the git.infradead.org repository to be
requested to pull.
http://git.infradead.org/users/kmpark/linux-samsung/shortlog/refs/heads/devfreq-for-next
As soon as infradead server gets synched, you can see the commit
message updated.
Cheers!
MyungJoo.
>>
>> 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>
>> ---
>> drivers/devfreq/devfreq.c | 44 ++++++++++++++++++++++++++++++----------
>> drivers/devfreq/exynos4_bus.c | 16 +++++++++++---
>> include/linux/devfreq.h | 18 ++++++++++++++--
>> 3 files changed, 60 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index a33fc6c..83392a6 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 options = 0;
>>
>> if (!mutex_is_locked(&devfreq->lock)) {
>> WARN(true, "devfreq->lock must be locked by the caller.\n");
>> @@ -104,18 +105,23 @@ 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)
>> + options &= ~(1 << 0);
>> + options |= DEVFREQ_OPTION_FREQ_LUB;
>> + }
>> + if (devfreq->max_freq && freq > devfreq->max_freq) {
>> freq = devfreq->max_freq;
>> - if (devfreq->min_freq && freq < devfreq->min_freq)
>> + options &= ~(1 << 0);
>> + options |= DEVFREQ_OPTION_FREQ_GLB;
>> + }
>> + if (devfreq->min_freq && freq < devfreq->min_freq) {
>> freq = devfreq->min_freq;
>> + options &= ~(1 << 0);
>> + options |= DEVFREQ_OPTION_FREQ_LUB;
>> + }
>>
>> - /*
>> - * 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, options);
>> if (err)
>> return err;
>>
>> @@ -771,14 +777,30 @@ 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
>> + * @floor false: find LUB first and use GLB if LUB not available.
>> + * true: find GLB first and use LUB if GLB not available.
>> + *
>> + * LUB: least upper bound (at least this freq or above, but the least)
>> + * GLB: greatest lower bound (at most this freq or below, but the most)
>> *
>> */
>> -struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq)
>> +struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq,
>> + bool floor)
>> {
>> - struct opp *opp = opp_find_freq_ceil(dev, freq);
>> + struct opp *opp;
>>
>> - if (opp == ERR_PTR(-ENODEV))
>> + if (floor) {
>> opp = opp_find_freq_floor(dev, freq);
>> +
>> + if (opp == ERR_PTR(-ENODEV))
>> + opp = opp_find_freq_ceil(dev, freq);
>> + } else {
>> + opp = opp_find_freq_ceil(dev, freq);
>> +
>> + 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..c0a78da 100644
>> --- a/drivers/devfreq/exynos4_bus.c
>> +++ b/drivers/devfreq/exynos4_bus.c
>> @@ -619,13 +619,21 @@ 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 options)
>> {
>> 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);
>> + unsigned long def = *_freq;
>> + 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, options &
>> + DEVFREQ_OPTION_FREQ_GLB);
>> 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 b853379..1aff012 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -59,6 +59,16 @@ struct devfreq_pm_qos_table {
>> s32 qos_value;
>> };
>>
>> +/*
>> + * target callback, which is to provide additional information to the
>> + * devfreq driver.
>> + */
>> +
>> +/* The resulting frequency should be at least this. (least upper bound) */
>> +#define DEVFREQ_OPTION_FREQ_LUB 0x0
>> +/* The resulting frequency should be at most this. (greatest lower bound) */
>> +#define DEVFREQ_OPTION_FREQ_GLB 0x1
>> +
>> /**
>> * struct devfreq_dev_profile - Devfreq's user device profile
>> * @initial_freq The operating frequency when devfreq_add_device() is
>> @@ -76,6 +86,8 @@ struct devfreq_pm_qos_table {
>> * higher than any operable frequency, set maximum.
>> * Before returning, target function should set
>> * freq at the current frequency.
>> + * The "option" parameter's possible values are
>> + * explained above with "DEVFREQ_OPTION_*" 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
>> @@ -95,7 +107,7 @@ struct devfreq_dev_profile {
>> bool qos_use_max;
>> struct devfreq_pm_qos_table *qos_list;
>>
>> - int (*target)(struct device *dev, unsigned long *freq);
>> + int (*target)(struct device *dev, unsigned long *freq, u32 options);
>> int (*get_dev_status)(struct device *dev,
>> struct devfreq_dev_status *stat);
>> void (*exit)(struct device *dev);
>> @@ -198,7 +210,7 @@ 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, bool floor);
>> extern int devfreq_register_opp_notifier(struct device *dev,
>> struct devfreq *devfreq);
>> extern int devfreq_unregister_opp_notifier(struct device *dev,
>> @@ -253,7 +265,7 @@ static int devfreq_remove_device(struct devfreq *devfreq)
>> }
>>
>> static struct opp *devfreq_recommended_opp(struct device *dev,
>> - unsigned long *freq)
>> + unsigned long *freq, bool floor)
>> {
>> return -EINVAL;
>> }
>> --
>> 1.7.4.1
>>
--
MyungJoo Ham, Ph.D.
Mobile Software Platform Lab, DMC Business, Samsung Electronics
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