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a03dacb031
Many CPU architectures have caches that can scale independent of the CPUs. Frequency scaling of the caches is necessary to make sure that the cache is not a performance bottleneck that leads to poor performance and power. The same idea applies for RAM/DDR. To achieve this, this patch adds support for cpu based scaling to the passive governor. This is accomplished by taking the current frequency of each CPU frequency domain and then adjust the frequency of the cache (or any devfreq device) based on the frequency of the CPUs. It listens to CPU frequency transition notifiers to keep itself up to date on the current CPU frequency. To decide the frequency of the device, the governor does one of the following: * Derives the optimal devfreq device opp from required-opps property of the parent cpu opp_table. * Scales the device frequency in proportion to the CPU frequency. So, if the CPUs are running at their max frequency, the device runs at its max frequency. If the CPUs are running at their min frequency, the device runs at its min frequency. It is interpolated for frequencies in between. Tested-by: Chen-Yu Tsai <wenst@chromium.org> Tested-by: Johnson Wang <johnson.wang@mediatek.com> Signed-off-by: Saravana Kannan <skannan@codeaurora.org> [Sibi: Integrated cpu-freqmap governor into passive_governor] Signed-off-by: Sibi Sankar <sibis@codeaurora.org> [Chanwoo: Fix conflict with latest code and cleanup code] Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
124 lines
4 KiB
C
124 lines
4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* governor.h - internal header for devfreq governors.
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*
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* Copyright (C) 2011 Samsung Electronics
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* MyungJoo Ham <myungjoo.ham@samsung.com>
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*
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* This header is for devfreq governors in drivers/devfreq/
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*/
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#ifndef _GOVERNOR_H
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#define _GOVERNOR_H
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#include <linux/devfreq.h>
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#define DEVFREQ_NAME_LEN 16
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#define to_devfreq(DEV) container_of((DEV), struct devfreq, dev)
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/* Devfreq events */
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#define DEVFREQ_GOV_START 0x1
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#define DEVFREQ_GOV_STOP 0x2
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#define DEVFREQ_GOV_UPDATE_INTERVAL 0x3
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#define DEVFREQ_GOV_SUSPEND 0x4
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#define DEVFREQ_GOV_RESUME 0x5
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#define DEVFREQ_MIN_FREQ 0
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#define DEVFREQ_MAX_FREQ ULONG_MAX
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/*
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* Definition of the governor feature flags
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* - DEVFREQ_GOV_FLAG_IMMUTABLE
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* : This governor is never changeable to other governors.
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* - DEVFREQ_GOV_FLAG_IRQ_DRIVEN
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* : The devfreq won't schedule the work for this governor.
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*/
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#define DEVFREQ_GOV_FLAG_IMMUTABLE BIT(0)
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#define DEVFREQ_GOV_FLAG_IRQ_DRIVEN BIT(1)
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/*
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* Definition of governor attribute flags except for common sysfs attributes
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* - DEVFREQ_GOV_ATTR_POLLING_INTERVAL
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* : Indicate polling_interval sysfs attribute
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* - DEVFREQ_GOV_ATTR_TIMER
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* : Indicate timer sysfs attribute
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*/
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#define DEVFREQ_GOV_ATTR_POLLING_INTERVAL BIT(0)
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#define DEVFREQ_GOV_ATTR_TIMER BIT(1)
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/**
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* struct devfreq_cpu_data - Hold the per-cpu data
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* @dev: reference to cpu device.
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* @first_cpu: the cpumask of the first cpu of a policy.
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* @opp_table: reference to cpu opp table.
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* @cur_freq: the current frequency of the cpu.
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* @min_freq: the min frequency of the cpu.
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* @max_freq: the max frequency of the cpu.
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*
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* This structure stores the required cpu_data of a cpu.
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* This is auto-populated by the governor.
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*/
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struct devfreq_cpu_data {
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struct device *dev;
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unsigned int first_cpu;
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struct opp_table *opp_table;
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unsigned int cur_freq;
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unsigned int min_freq;
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unsigned int max_freq;
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};
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/**
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* struct devfreq_governor - Devfreq policy governor
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* @node: list node - contains registered devfreq governors
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* @name: Governor's name
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* @attrs: Governor's sysfs attribute flags
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* @flags: Governor's feature flags
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* @get_target_freq: Returns desired operating frequency for the device.
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* Basically, get_target_freq will run
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* devfreq_dev_profile.get_dev_status() to get the
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* status of the device (load = busy_time / total_time).
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* @event_handler: Callback for devfreq core framework to notify events
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* to governors. Events include per device governor
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* init and exit, opp changes out of devfreq, suspend
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* and resume of per device devfreq during device idle.
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*
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* Note that the callbacks are called with devfreq->lock locked by devfreq.
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*/
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struct devfreq_governor {
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struct list_head node;
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const char name[DEVFREQ_NAME_LEN];
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const u64 attrs;
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const u64 flags;
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int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
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int (*event_handler)(struct devfreq *devfreq,
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unsigned int event, void *data);
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};
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void devfreq_monitor_start(struct devfreq *devfreq);
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void devfreq_monitor_stop(struct devfreq *devfreq);
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void devfreq_monitor_suspend(struct devfreq *devfreq);
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void devfreq_monitor_resume(struct devfreq *devfreq);
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void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay);
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int devfreq_add_governor(struct devfreq_governor *governor);
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int devfreq_remove_governor(struct devfreq_governor *governor);
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int devm_devfreq_add_governor(struct device *dev,
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struct devfreq_governor *governor);
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int devfreq_update_status(struct devfreq *devfreq, unsigned long freq);
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int devfreq_update_target(struct devfreq *devfreq, unsigned long freq);
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void devfreq_get_freq_range(struct devfreq *devfreq, unsigned long *min_freq,
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unsigned long *max_freq);
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static inline int devfreq_update_stats(struct devfreq *df)
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{
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if (!df->profile->get_dev_status)
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return -EINVAL;
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return df->profile->get_dev_status(df->dev.parent, &df->last_status);
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}
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#endif /* _GOVERNOR_H */
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