From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932130AbbLNJEu (ORCPT ); Mon, 14 Dec 2015 04:04:50 -0500 Received: from mailout3.samsung.com ([203.254.224.33]:42807 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752627AbbLNJEm (ORCPT ); Mon, 14 Dec 2015 04:04:42 -0500 X-AuditID: cbfee68d-f79646d000001355-87-566e8626dea8 Date: Mon, 14 Dec 2015 09:04:38 +0000 (GMT) From: MyungJoo Ham Subject: Re: [PATCH v4 05/20] PM / devfreq: Add new passive governor To: =?utf-8?Q?=EC=B5=9C=EC=B0=AC=EC=9A=B0?= , =?utf-8?Q?=ED=81=AC=EC=89=AC=EC=8B=9C=ED=86=A0=ED=94=84?= , "kgene@kernel.org" Cc: =?utf-8?Q?=EB=B0=95=EA=B2=BD=EB=AF=BC?= , "robh+dt@kernel.org" , "pawel.moll@arm.com" , "mark.rutland@arm.com" , "ijc+devicetree@hellion.org.uk" , "galak@codeaurora.org" , "linux@arm.linux.org.uk" , "tjakobi@math.uni-bielefeld.de" , "linux.amoon@gmail.com" , "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" , "linux-samsung-soc@vger.kernel.org" , "devicetree@vger.kernel.org" Reply-to: myungjoo.ham@samsung.com MIME-version: 1.0 X-MTR: 20151214090426338@myungjoo.ham Msgkey: 20151214090426338@myungjoo.ham X-EPLocale: ko_KR.utf-8 X-Priority: 3 X-EPWebmail-Msg-Type: personal X-EPWebmail-Reply-Demand: 0 X-EPApproval-Locale: X-EPHeader: ML X-MLAttribute: X-RootMTR: 20151214090426338@myungjoo.ham X-ParentMTR: X-ArchiveUser: X-CPGSPASS: N X-ConfirmMail: N,general Content-type: text/plain; charset=utf-8 MIME-version: 1.0 Message-id: <1874820122.661091450083873584.JavaMail.weblogic@epmlwas07b> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrKIsWRmVeSWpSXmKPExsWyRsSkUFetLS/M4MMxYYvLu+awOTB6fN4k F8AYxWWTkpqTWZZapG+XwJVx8speloJ7ARVd534xNTBe8Oti5OQQElCXWLTkJBuILSFgIrH+ 1z5WCFtM4sK99UBxLqCapYwSp2adZoYpOrBzGSNEYg6jxM/vp1hAEiwCqhJrX08FSnBwsAno Scz8nAwSFhZwkbh+YzkLSL2IwHFGiWNXNoA1Mwt8ZZVY+OA/G8QZShJr9r0CG8QrIChxcuYT FohtqhIXZr1jhoirSfTsOwcVF5e4MPcSO4TNKzGj/SlUXE5i2tc1UJdKS5yfBbIM4p3F3x9D xfkljt3ewQRhC0hMPXMQqkZLYvPq81A1fBJrFr5lganfdWo5M8yu+1vmQvVKSGxteQIOLmYB RYkp3Q/ZQZ5nFtCUWL9LH90rvAIeEqdaZ4ADQkJgKofE1c1HWCYwKs1CUjcLyahZCKOQlSxg ZFnFKJpakFxQnJReZKhXnJhbXJqXrpecn7uJEZgaTv971ruD8fYB60OMAhyMSjy8Gctyw4RY E8uKK3MPMZoCo2kis5Rocj4wAeWVxBsamxlZmJqYGhuZW5opifMqSv0MFhJITyxJzU5NLUgt ii8qzUktPsTIxMEp1cBYnb005eKLTUnMEVe9ha8oiKZG/1ZO+/DRKPd35hdp3tgDIdllS/ni TbLm2RQV771fPqksL6om6/8cWV6x9wEtzvb/T2iuYI1Tf3lpB9/nabP+x646c1d4uegdwdYl T7jiqs+vW6chW5Vc1RW6L8z1iLWzyoaOqy90d1WvFylfKeg491uN0nYlluKMREMt5qLiRACS rF9rCAMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrGKsWRmVeSWpSXmKPExsVy+t/tfl21trwwg29b+Swu75rD5sDo8XmT XABjVJpNRmpiSmqRQmpecn5KZl66rZJ3cLxzvKmZgaGuoaWFuZJCXmJuqq2Si0+ArltmDtBQ JYWyxJxSoFBAYnGxkr6dTVF+aUmqQkZ+cYmtUrShuZGekYGeqZGeoXGslaGBgZEpUE1CWsbJ K3tZCu4FVHSd+8XUwHjBr4uRk0NIQF1i0ZKTbCC2hICJxIGdyxghbDGJC/fWA8W5gGrmMEr8 /H6KBSTBIqAqsfb1VKAiDg42AT2JmZ+TQcLCAi4S128sZwGpFxE4zihx7MoGRhCHWeArq8TC B//ZILYpSazZ9wpsEK+AoMTJmU9YILapSlyY9Y4ZIq4m0bPvHFRcXOLC3EvsEDavxIz2p1Bx OYlpX9cwQ9jSEudnbYC7evH3x1Bxfoljt3cwQdgCElPPHISq0ZLYvPo8VA2fxJqFb1lg6ned Ws4Ms+v+lrlQvRISW1uesILYzAKKElO6H7KDPM8soCmxfpc+uld4BTwkTrXOYJnAKDsLSWoW ku5ZCN3IShYwsqxiFE0tSC4oTkqvMNYrTswtLs1L10vOz93ECE5DzxbvYPx/3voQowAHoxIP b8ay3DAh1sSy4srcQ4wSHMxKIrwJVnlhQrwpiZVVqUX58UWlOanFhxhNgZE2kVlKNDkfmCLz SuINjY1NzExMLU0sDEzNlcR5b+/zCxMSSE8sSc1OTS1ILYLpY+LglGpgjAr33SnXpnWi/2aD m1nCxqOzOSc9sTBOc972TzvRmP9BBtOi0J+SyzIOR57Uz2ELVedwVdkittBL/UjUAo/5Wzf8 XG9763DzL5vACV+OfHazjDZX3V3Ec+bYp0tTPPz/WbC9TmF7vjtw2Qt/tvj/k+o3FCsKW1ye tMlYJq7yxVud6Is+sgGHlFiKMxINtZiLihMBnFUISlkDAAA= DLP-Filter: Pass X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id tBE94ve9024063 > > This patch adds the new passive governor for DEVFREQ framework. The following > governors are already present and used for DVFS (Dynamic Voltage and Frequency > Scaling) drivers. The following governors are independently used for one device > driver which don't give the influence to other device drviers and also don't > receive the effect from other device drivers. > - ondemand / performance / powersave / userspace > > The passive governor depends on operation of parent driver with specific > governos extremely and is not able to decide the new frequency by oneself. > According to the decided new frequency of parent driver with governor, > the passive governor uses it to decide the appropriate frequency for own > device driver. The passive governor must need the following information > from device tree: > - the source clock and OPP tables > - the instance of parent device > > For exameple, > there are one more devfreq device drivers which need to change their source > clock according to their utilization on runtime. But, they share the same > power line (e.g., regulator). So, specific device driver is operated as parent > with ondemand governor and then the rest device driver with passive governor > is influenced by parent device. > > Suggested-by: Myungjoo Ham > Signed-off-by: Chanwoo Choi > [linux.amoon: Tested on Odroid U3] > Tested-by: Anand Moon > --- > drivers/devfreq/Kconfig | 9 ++++ > drivers/devfreq/Makefile | 1 + > drivers/devfreq/devfreq.c | 47 ++++++++++++++++ > drivers/devfreq/governor_passive.c | 108 +++++++++++++++++++++++++++++++++++++ > include/linux/devfreq.h | 15 ++++++ > 5 files changed, 180 insertions(+) > create mode 100644 drivers/devfreq/governor_passive.c > > diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > index 55ec774f794c..d03f635a93e1 100644 > --- a/drivers/devfreq/Kconfig > +++ b/drivers/devfreq/Kconfig > @@ -64,6 +64,15 @@ config DEVFREQ_GOV_USERSPACE > Otherwise, the governor does not change the frequnecy > given at the initialization. > > +config DEVFREQ_GOV_PASSIVE > + tristate "Passive" > + help > + Sets the frequency by other governors (simple_ondemand, performance, > + powersave, usersapce) of a parent devfreq device. This governor > + always has the dependency on the chosen frequency from paired > + governor. This governor does not change the frequency by oneself > + through sysfs entry. Sets the frequency based on the frequency of its parent devfreq device. This governor does not change the frequency by itself through sysfs entries. > + > comment "DEVFREQ Drivers" > > config ARM_EXYNOS_BUS_DEVFREQ > diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile > index 375ebbb4fcfb..f81c313b4b79 100644 > --- a/drivers/devfreq/Makefile > +++ b/drivers/devfreq/Makefile [] > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index 984c5e9e7bdd..15e58779e4c0 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -190,6 +190,31 @@ static struct devfreq_governor *find_devfreq_governor(const char *name) > > /* Load monitoring helper functions for governors use */ > > +static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq) > +{ > + struct devfreq *passive; > + unsigned long rate; > + int ret; > + > + list_for_each_entry(passive, &devfreq->passive_dev_list, passive_node) { > + if (!passive->governor) > + continue; > + rate = freq; > + > + ret = passive->governor->get_target_freq(passive, &rate); > + if (ret) > + return ret; > + > + ret = passive->profile->target(passive->dev.parent, &rate, 0); > + if (ret) > + return ret; > + > + passive->previous_freq = rate; > + } > + > + return 0; > +} > + > /** > * update_devfreq() - Reevaluate the device and configure frequency. > * @devfreq: the devfreq instance. > @@ -233,10 +258,18 @@ int update_devfreq(struct devfreq *devfreq) > flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */ > } > > + if (!list_empty(&devfreq->passive_dev_list) > + && devfreq->previous_freq > freq) > + update_devfreq_passive(devfreq, freq); > + Could you please comment somewhere appropriate that the dependent is going to be changed before its parent if the frequency is going down. (and after if going up) And state why as well. And, is this viable universally? > err = devfreq->profile->target(devfreq->dev.parent, &freq, flags); > if (err) > return err; > > + if (!list_empty(&devfreq->passive_dev_list) > + && devfreq->previous_freq < freq) > + update_devfreq_passive(devfreq, freq); > + > if (devfreq->profile->freq_table) > if (devfreq_update_status(devfreq, freq)) > dev_err(&devfreq->dev, > @@ -442,6 +475,10 @@ static void _remove_devfreq(struct devfreq *devfreq) > return; > } > list_del(&devfreq->node); > + list_del(&devfreq->passive_node); > + if (!list_empty(&devfreq->passive_dev_list)) > + list_del_init(&devfreq->passive_dev_list); > + > mutex_unlock(&devfreq_list_lock); > > if (devfreq->governor) > @@ -559,6 +596,16 @@ struct devfreq *devfreq_add_device(struct device *dev, > goto err_init; > } > > + if (!strncmp(devfreq->governor_name, "passive", 7)) { > + struct devfreq *parent_devfreq = > + ((struct devfreq_passive_data *)data)->parent; > + > + list_add(&devfreq->passive_node, > + &parent_devfreq->passive_dev_list); > + } else { > + INIT_LIST_HEAD(&devfreq->passive_dev_list); > + } > + > return devfreq; > > err_init: This code has become too much invasive to devfreq.c while being too special for the passive governor. Why don't you add notifier chain to devfreq.c, which can be used by anyone else as well, and use that notifier for passive governor? You may refer to "cpufreq_register_notifier()" with CPUFREQ_TRANSITION_NOTIFIER. > diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c > new file mode 100644 Then, utilizing notifier-block at governor_passive.c becomes possible. You will also be able to write any frequency deciding code inside governor_passive.c as well, not in devfreq.c. > diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h > index 6fa02a20eb63..95c54578a1b4 100644 > --- a/include/linux/devfreq.h > +++ b/include/linux/devfreq.h > @@ -177,6 +177,9 @@ struct devfreq { > unsigned int *trans_table; > unsigned long *time_in_state; > unsigned long last_stat_updated; > + > + struct list_head passive_dev_list; > + struct list_head passive_node; > }; You will need only one notifier head here. > > #if defined(CONFIG_PM_DEVFREQ) > @@ -241,6 +244,18 @@ struct devfreq_simple_ondemand_data { > }; > #endif > > +/** > + * struct devfreq_passive_data - void *data fed to struct devfreq > + * and devfreq_add_device > + * @parent: The parent devfreq device. > + * > + * If the fed devfreq_passive_data pointer is NULL to the governor, > + * the governor return ERROR. > + */ > +struct devfreq_passive_data { > + struct devfreq *parent; > +}; > + Please enclose the above with #if > #else /* !CONFIG_PM_DEVFREQ */ > static inline struct devfreq *devfreq_add_device(struct device *dev, > struct devfreq_dev_profile *profile, > -- > 1.9.1 > {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I