blob: 3026bc22b374ad63ec98dd00cee43a475a4e0fb7 [file] [log] [blame]
/*
* Copyright (c) 2013-2017, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) "bw-hwmon: " fmt
#include <linux/kernel.h>
#include <linux/sizes.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/ktime.h>
#include <linux/time.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/mutex.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/devfreq.h>
#include <trace/events/power.h>
#include "governor.h"
#include "governor_bw_hwmon.h"
#define NUM_MBPS_ZONES 10
struct hwmon_node {
unsigned int guard_band_mbps;
unsigned int decay_rate;
unsigned int io_percent;
unsigned int bw_step;
unsigned int sample_ms;
unsigned int up_scale;
unsigned int up_thres;
unsigned int down_thres;
unsigned int down_count;
unsigned int hist_memory;
unsigned int hyst_trigger_count;
unsigned int hyst_length;
unsigned int idle_mbps;
unsigned int mbps_zones[NUM_MBPS_ZONES];
unsigned long prev_ab;
unsigned long *dev_ab;
unsigned long resume_freq;
unsigned long resume_ab;
unsigned long bytes;
unsigned long max_mbps;
unsigned long hist_max_mbps;
unsigned long hist_mem;
unsigned long hyst_peak;
unsigned long hyst_mbps;
unsigned long hyst_trig_win;
unsigned long hyst_en;
unsigned long prev_req;
unsigned int wake;
unsigned int down_cnt;
ktime_t prev_ts;
ktime_t hist_max_ts;
bool sampled;
bool mon_started;
struct list_head list;
void *orig_data;
struct bw_hwmon *hw;
struct devfreq_governor *gov;
struct attribute_group *attr_grp;
};
#define UP_WAKE 1
#define DOWN_WAKE 2
static DEFINE_SPINLOCK(irq_lock);
static LIST_HEAD(hwmon_list);
static DEFINE_MUTEX(list_lock);
static int use_cnt;
static DEFINE_MUTEX(state_lock);
#define show_attr(name) \
static ssize_t show_##name(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
struct devfreq *df = to_devfreq(dev); \
struct hwmon_node *hw = df->data; \
return snprintf(buf, PAGE_SIZE, "%u\n", hw->name); \
}
#define store_attr(name, _min, _max) \
static ssize_t store_##name(struct device *dev, \
struct device_attribute *attr, const char *buf, \
size_t count) \
{ \
struct devfreq *df = to_devfreq(dev); \
struct hwmon_node *hw = df->data; \
int ret; \
unsigned int val; \
ret = kstrtoint(buf, 10, &val); \
if (ret) \
return ret; \
val = max(val, _min); \
val = min(val, _max); \
hw->name = val; \
return count; \
}
#define gov_attr(__attr, min, max) \
show_attr(__attr) \
store_attr(__attr, (min), (max)) \
static DEVICE_ATTR(__attr, 0644, show_##__attr, store_##__attr)
#define show_list_attr(name, n) \
static ssize_t show_list_##name(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
struct devfreq *df = to_devfreq(dev); \
struct hwmon_node *hw = df->data; \
unsigned int i, cnt = 0; \
\
for (i = 0; i < n && hw->name[i]; i++) \
cnt += snprintf(buf + cnt, PAGE_SIZE, "%u ", hw->name[i]);\
cnt += snprintf(buf + cnt, PAGE_SIZE, "\n"); \
return cnt; \
}
#define store_list_attr(name, n, _min, _max) \
static ssize_t store_list_##name(struct device *dev, \
struct device_attribute *attr, const char *buf, \
size_t count) \
{ \
struct devfreq *df = to_devfreq(dev); \
struct hwmon_node *hw = df->data; \
int ret, numvals; \
unsigned int i = 0, val; \
char **strlist; \
\
strlist = argv_split(GFP_KERNEL, buf, &numvals); \
if (!strlist) \
return -ENOMEM; \
numvals = min(numvals, n - 1); \
for (i = 0; i < numvals; i++) { \
ret = kstrtouint(strlist[i], 10, &val); \
if (ret) \
goto out; \
val = max(val, _min); \
val = min(val, _max); \
hw->name[i] = val; \
} \
ret = count; \
out: \
argv_free(strlist); \
hw->name[i] = 0; \
return ret; \
}
#define gov_list_attr(__attr, n, min, max) \
show_list_attr(__attr, n) \
store_list_attr(__attr, n, (min), (max)) \
static DEVICE_ATTR(__attr, 0644, show_list_##__attr, store_list_##__attr)
#define MIN_MS 10U
#define MAX_MS 500U
/* Returns MBps of read/writes for the sampling window. */
static unsigned int bytes_to_mbps(long long bytes, unsigned int us)
{
bytes *= USEC_PER_SEC;
do_div(bytes, us);
bytes = DIV_ROUND_UP_ULL(bytes, SZ_1M);
return bytes;
}
static unsigned int mbps_to_bytes(unsigned long mbps, unsigned int ms)
{
mbps *= ms;
mbps = DIV_ROUND_UP(mbps, MSEC_PER_SEC);
mbps *= SZ_1M;
return mbps;
}
static int __bw_hwmon_sw_sample_end(struct bw_hwmon *hwmon)
{
struct devfreq *df;
struct hwmon_node *node;
ktime_t ts;
unsigned long bytes, mbps;
unsigned int us;
int wake = 0;
df = hwmon->df;
node = df->data;
ts = ktime_get();
us = ktime_to_us(ktime_sub(ts, node->prev_ts));
bytes = hwmon->get_bytes_and_clear(hwmon);
bytes += node->bytes;
node->bytes = 0;
mbps = bytes_to_mbps(bytes, us);
node->max_mbps = max(node->max_mbps, mbps);
/*
* If the measured bandwidth in a micro sample is greater than the
* wake up threshold, it indicates an increase in load that's non
* trivial. So, have the governor ignore historical idle time or low
* bandwidth usage and do the bandwidth calculation based on just
* this micro sample.
*/
if (mbps > node->hw->up_wake_mbps) {
wake = UP_WAKE;
} else if (mbps < node->hw->down_wake_mbps) {
if (node->down_cnt)
node->down_cnt--;
if (node->down_cnt <= 0)
wake = DOWN_WAKE;
}
node->prev_ts = ts;
node->wake = wake;
node->sampled = true;
trace_bw_hwmon_meas(dev_name(df->dev.parent),
mbps,
us,
wake);
return wake;
}
static int __bw_hwmon_hw_sample_end(struct bw_hwmon *hwmon)
{
struct devfreq *df;
struct hwmon_node *node;
unsigned long bytes, mbps;
int wake = 0;
df = hwmon->df;
node = df->data;
/*
* If this read is in response to an IRQ, the HW monitor should
* return the measurement in the micro sample that triggered the IRQ.
* Otherwise, it should return the maximum measured value in any
* micro sample since the last time we called get_bytes_and_clear()
*/
bytes = hwmon->get_bytes_and_clear(hwmon);
mbps = bytes_to_mbps(bytes, node->sample_ms * USEC_PER_MSEC);
node->max_mbps = mbps;
if (mbps > node->hw->up_wake_mbps)
wake = UP_WAKE;
else if (mbps < node->hw->down_wake_mbps)
wake = DOWN_WAKE;
node->wake = wake;
node->sampled = true;
trace_bw_hwmon_meas(dev_name(df->dev.parent),
mbps,
node->sample_ms * USEC_PER_MSEC,
wake);
return 1;
}
static int __bw_hwmon_sample_end(struct bw_hwmon *hwmon)
{
if (hwmon->set_hw_events)
return __bw_hwmon_hw_sample_end(hwmon);
else
return __bw_hwmon_sw_sample_end(hwmon);
}
int bw_hwmon_sample_end(struct bw_hwmon *hwmon)
{
unsigned long flags;
int wake;
spin_lock_irqsave(&irq_lock, flags);
wake = __bw_hwmon_sample_end(hwmon);
spin_unlock_irqrestore(&irq_lock, flags);
return wake;
}
unsigned long to_mbps_zone(struct hwmon_node *node, unsigned long mbps)
{
int i;
for (i = 0; i < NUM_MBPS_ZONES && node->mbps_zones[i]; i++)
if (node->mbps_zones[i] >= mbps)
return node->mbps_zones[i];
return node->hw->df->max_freq;
}
#define MIN_MBPS 500UL
#define HIST_PEAK_TOL 60
static unsigned long get_bw_and_set_irq(struct hwmon_node *node,
unsigned long *freq, unsigned long *ab)
{
unsigned long meas_mbps, thres, flags, req_mbps, adj_mbps;
unsigned long meas_mbps_zone;
unsigned long hist_lo_tol, hyst_lo_tol;
struct bw_hwmon *hw = node->hw;
unsigned int new_bw, io_percent = node->io_percent;
ktime_t ts;
unsigned int ms = 0;
spin_lock_irqsave(&irq_lock, flags);
if (!hw->set_hw_events) {
ts = ktime_get();
ms = ktime_to_ms(ktime_sub(ts, node->prev_ts));
}
if (!node->sampled || ms >= node->sample_ms)
__bw_hwmon_sample_end(node->hw);
node->sampled = false;
req_mbps = meas_mbps = node->max_mbps;
node->max_mbps = 0;
hist_lo_tol = (node->hist_max_mbps * HIST_PEAK_TOL) / 100;
/* Remember historic peak in the past hist_mem decision windows. */
if (meas_mbps > node->hist_max_mbps || !node->hist_mem) {
/* If new max or no history */
node->hist_max_mbps = meas_mbps;
node->hist_mem = node->hist_memory;
} else if (meas_mbps >= hist_lo_tol) {
/*
* If subsequent peaks come close (within tolerance) to but
* less than the historic peak, then reset the history start,
* but not the peak value.
*/
node->hist_mem = node->hist_memory;
} else {
/* Count down history expiration. */
if (node->hist_mem)
node->hist_mem--;
}
/*
* The AB value that corresponds to the lowest mbps zone greater than
* or equal to the "frequency" the current measurement will pick.
* This upper limit is useful for balancing out any prediction
* mechanisms to be power friendly.
*/
meas_mbps_zone = (meas_mbps * 100) / io_percent;
meas_mbps_zone = to_mbps_zone(node, meas_mbps_zone);
meas_mbps_zone = (meas_mbps_zone * io_percent) / 100;
meas_mbps_zone = max(meas_mbps, meas_mbps_zone);
/*
* If this is a wake up due to BW increase, vote much higher BW than
* what we measure to stay ahead of increasing traffic and then set
* it up to vote for measured BW if we see down_count short sample
* windows of low traffic.
*/
if (node->wake == UP_WAKE) {
req_mbps += ((meas_mbps - node->prev_req)
* node->up_scale) / 100;
/*
* However if the measured load is less than the historic
* peak, but the over request is higher than the historic
* peak, then we could limit the over requesting to the
* historic peak.
*/
if (req_mbps > node->hist_max_mbps
&& meas_mbps < node->hist_max_mbps)
req_mbps = node->hist_max_mbps;
req_mbps = min(req_mbps, meas_mbps_zone);
}
hyst_lo_tol = (node->hyst_mbps * HIST_PEAK_TOL) / 100;
if (meas_mbps > node->hyst_mbps && meas_mbps > MIN_MBPS) {
hyst_lo_tol = (meas_mbps * HIST_PEAK_TOL) / 100;
node->hyst_peak = 0;
node->hyst_trig_win = node->hyst_length;
node->hyst_mbps = meas_mbps;
}
/*
* Check node->max_mbps to avoid double counting peaks that cause
* early termination of a window.
*/
if (meas_mbps >= hyst_lo_tol && meas_mbps > MIN_MBPS
&& !node->max_mbps) {
node->hyst_peak++;
if (node->hyst_peak >= node->hyst_trigger_count
|| node->hyst_en)
node->hyst_en = node->hyst_length;
}
if (node->hyst_trig_win)
node->hyst_trig_win--;
if (node->hyst_en)
node->hyst_en--;
if (!node->hyst_trig_win && !node->hyst_en) {
node->hyst_peak = 0;
node->hyst_mbps = 0;
}
if (node->hyst_en) {
if (meas_mbps > node->idle_mbps)
req_mbps = max(req_mbps, node->hyst_mbps);
}
/* Stretch the short sample window size, if the traffic is too low */
if (meas_mbps < MIN_MBPS) {
hw->up_wake_mbps = (max(MIN_MBPS, req_mbps)
* (100 + node->up_thres)) / 100;
hw->down_wake_mbps = 0;
hw->undo_over_req_mbps = 0;
thres = mbps_to_bytes(max(MIN_MBPS, req_mbps / 2),
node->sample_ms);
} else {
/*
* Up wake vs down wake are intentionally a percentage of
* req_mbps vs meas_mbps to make sure the over requesting
* phase is handled properly. We only want to wake up and
* reduce the vote based on the measured mbps being less than
* the previous measurement that caused the "over request".
*/
hw->up_wake_mbps = (req_mbps * (100 + node->up_thres)) / 100;
hw->down_wake_mbps = (meas_mbps * node->down_thres) / 100;
if (node->wake == UP_WAKE)
hw->undo_over_req_mbps = min(req_mbps, meas_mbps_zone);
else
hw->undo_over_req_mbps = 0;
thres = mbps_to_bytes(meas_mbps, node->sample_ms);
}
if (hw->set_hw_events) {
hw->down_cnt = node->down_count;
hw->set_hw_events(hw, node->sample_ms);
} else {
node->down_cnt = node->down_count;
node->bytes = hw->set_thres(hw, thres);
}
node->wake = 0;
node->prev_req = req_mbps;
spin_unlock_irqrestore(&irq_lock, flags);
adj_mbps = req_mbps + node->guard_band_mbps;
if (adj_mbps > node->prev_ab) {
new_bw = adj_mbps;
} else {
new_bw = adj_mbps * node->decay_rate
+ node->prev_ab * (100 - node->decay_rate);
new_bw /= 100;
}
node->prev_ab = new_bw;
if (ab)
*ab = roundup(new_bw, node->bw_step);
*freq = (new_bw * 100) / io_percent;
trace_bw_hwmon_update(dev_name(node->hw->df->dev.parent),
new_bw,
*freq,
hw->up_wake_mbps,
hw->down_wake_mbps);
return req_mbps;
}
static struct hwmon_node *find_hwmon_node(struct devfreq *df)
{
struct hwmon_node *node, *found = NULL;
mutex_lock(&list_lock);
list_for_each_entry(node, &hwmon_list, list)
if (node->hw->dev == df->dev.parent ||
node->hw->of_node == df->dev.parent->of_node ||
(!node->hw->dev && !node->hw->of_node &&
node->gov == df->governor)) {
found = node;
break;
}
mutex_unlock(&list_lock);
return found;
}
int update_bw_hwmon(struct bw_hwmon *hwmon)
{
struct devfreq *df;
struct hwmon_node *node;
int ret;
if (!hwmon)
return -EINVAL;
df = hwmon->df;
if (!df)
return -ENODEV;
node = df->data;
if (!node)
return -ENODEV;
if (!node->mon_started)
return -EBUSY;
dev_dbg(df->dev.parent, "Got update request\n");
devfreq_monitor_stop(df);
mutex_lock(&df->lock);
ret = update_devfreq(df);
if (ret)
dev_err(df->dev.parent,
"Unable to update freq on request!\n");
mutex_unlock(&df->lock);
devfreq_monitor_start(df);
return 0;
}
static int start_monitor(struct devfreq *df, bool init)
{
struct hwmon_node *node = df->data;
struct bw_hwmon *hw = node->hw;
struct device *dev = df->dev.parent;
unsigned long mbps;
int ret;
node->prev_ts = ktime_get();
if (init) {
node->prev_ab = 0;
node->resume_freq = 0;
node->resume_ab = 0;
mbps = (df->previous_freq * node->io_percent) / 100;
hw->up_wake_mbps = mbps;
hw->down_wake_mbps = MIN_MBPS;
hw->undo_over_req_mbps = 0;
ret = hw->start_hwmon(hw, mbps);
} else {
ret = hw->resume_hwmon(hw);
}
if (ret) {
dev_err(dev, "Unable to start HW monitor! (%d)\n", ret);
return ret;
}
if (init)
devfreq_monitor_start(df);
else
devfreq_monitor_resume(df);
node->mon_started = true;
return 0;
}
static void stop_monitor(struct devfreq *df, bool init)
{
struct hwmon_node *node = df->data;
struct bw_hwmon *hw = node->hw;
node->mon_started = false;
if (init) {
devfreq_monitor_stop(df);
hw->stop_hwmon(hw);
} else {
devfreq_monitor_suspend(df);
hw->suspend_hwmon(hw);
}
}
static int gov_start(struct devfreq *df)
{
int ret = 0;
struct device *dev = df->dev.parent;
struct hwmon_node *node;
struct bw_hwmon *hw;
struct devfreq_dev_status stat;
node = find_hwmon_node(df);
if (!node) {
dev_err(dev, "Unable to find HW monitor!\n");
return -ENODEV;
}
hw = node->hw;
stat.private_data = NULL;
if (df->profile->get_dev_status)
ret = df->profile->get_dev_status(df->dev.parent, &stat);
if (ret || !stat.private_data)
dev_warn(dev, "Device doesn't take AB votes!\n");
else
node->dev_ab = stat.private_data;
hw->df = df;
node->orig_data = df->data;
df->data = node;
if (start_monitor(df, true))
goto err_start;
ret = sysfs_create_group(&df->dev.kobj, node->attr_grp);
if (ret)
goto err_sysfs;
return 0;
err_sysfs:
stop_monitor(df, true);
err_start:
df->data = node->orig_data;
node->orig_data = NULL;
hw->df = NULL;
node->dev_ab = NULL;
return ret;
}
static void gov_stop(struct devfreq *df)
{
struct hwmon_node *node = df->data;
struct bw_hwmon *hw = node->hw;
sysfs_remove_group(&df->dev.kobj, node->attr_grp);
stop_monitor(df, true);
df->data = node->orig_data;
node->orig_data = NULL;
hw->df = NULL;
/*
* Not all governors know about this additional extended device
* configuration. To avoid leaving the extended configuration at a
* stale state, set it to 0 and let the next governor take it from
* there.
*/
if (node->dev_ab)
*node->dev_ab = 0;
node->dev_ab = NULL;
}
static int gov_suspend(struct devfreq *df)
{
struct hwmon_node *node = df->data;
unsigned long resume_freq = df->previous_freq;
unsigned long resume_ab = *node->dev_ab;
if (!node->hw->suspend_hwmon)
return -ENOSYS;
if (node->resume_freq) {
dev_warn(df->dev.parent, "Governor already suspended!\n");
return -EBUSY;
}
stop_monitor(df, false);
mutex_lock(&df->lock);
update_devfreq(df);
mutex_unlock(&df->lock);
node->resume_freq = resume_freq;
node->resume_ab = resume_ab;
return 0;
}
static int gov_resume(struct devfreq *df)
{
struct hwmon_node *node = df->data;
if (!node->hw->resume_hwmon)
return -ENOSYS;
if (!node->resume_freq) {
dev_warn(df->dev.parent, "Governor already resumed!\n");
return -EBUSY;
}
mutex_lock(&df->lock);
update_devfreq(df);
mutex_unlock(&df->lock);
node->resume_freq = 0;
node->resume_ab = 0;
return start_monitor(df, false);
}
static int devfreq_bw_hwmon_get_freq(struct devfreq *df,
unsigned long *freq)
{
struct hwmon_node *node = df->data;
/* Suspend/resume sequence */
if (!node->mon_started) {
*freq = node->resume_freq;
*node->dev_ab = node->resume_ab;
return 0;
}
get_bw_and_set_irq(node, freq, node->dev_ab);
return 0;
}
static ssize_t store_throttle_adj(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct devfreq *df = to_devfreq(dev);
struct hwmon_node *node = df->data;
int ret;
unsigned int val;
if (!node->hw->set_throttle_adj)
return -ENOSYS;
ret = kstrtouint(buf, 10, &val);
if (ret)
return ret;
ret = node->hw->set_throttle_adj(node->hw, val);
if (!ret)
return count;
else
return ret;
}
static ssize_t show_throttle_adj(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct devfreq *df = to_devfreq(dev);
struct hwmon_node *node = df->data;
unsigned int val;
if (!node->hw->get_throttle_adj)
val = 0;
else
val = node->hw->get_throttle_adj(node->hw);
return snprintf(buf, PAGE_SIZE, "%u\n", val);
}
static DEVICE_ATTR(throttle_adj, 0644, show_throttle_adj,
store_throttle_adj);
gov_attr(guard_band_mbps, 0U, 2000U);
gov_attr(decay_rate, 0U, 100U);
gov_attr(io_percent, 1U, 100U);
gov_attr(bw_step, 50U, 1000U);
gov_attr(sample_ms, 1U, 50U);
gov_attr(up_scale, 0U, 500U);
gov_attr(up_thres, 1U, 100U);
gov_attr(down_thres, 0U, 90U);
gov_attr(down_count, 0U, 90U);
gov_attr(hist_memory, 0U, 90U);
gov_attr(hyst_trigger_count, 0U, 90U);
gov_attr(hyst_length, 0U, 90U);
gov_attr(idle_mbps, 0U, 2000U);
gov_list_attr(mbps_zones, NUM_MBPS_ZONES, 0U, UINT_MAX);
static struct attribute *dev_attr[] = {
&dev_attr_guard_band_mbps.attr,
&dev_attr_decay_rate.attr,
&dev_attr_io_percent.attr,
&dev_attr_bw_step.attr,
&dev_attr_sample_ms.attr,
&dev_attr_up_scale.attr,
&dev_attr_up_thres.attr,
&dev_attr_down_thres.attr,
&dev_attr_down_count.attr,
&dev_attr_hist_memory.attr,
&dev_attr_hyst_trigger_count.attr,
&dev_attr_hyst_length.attr,
&dev_attr_idle_mbps.attr,
&dev_attr_mbps_zones.attr,
&dev_attr_throttle_adj.attr,
NULL,
};
static struct attribute_group dev_attr_group = {
.name = "bw_hwmon",
.attrs = dev_attr,
};
static int devfreq_bw_hwmon_ev_handler(struct devfreq *df,
unsigned int event, void *data)
{
int ret = 0;
unsigned int sample_ms;
struct hwmon_node *node;
struct bw_hwmon *hw;
mutex_lock(&state_lock);
switch (event) {
case DEVFREQ_GOV_START:
sample_ms = df->profile->polling_ms;
sample_ms = max(MIN_MS, sample_ms);
sample_ms = min(MAX_MS, sample_ms);
df->profile->polling_ms = sample_ms;
ret = gov_start(df);
if (ret)
goto out;
dev_dbg(df->dev.parent,
"Enabled dev BW HW monitor governor\n");
break;
case DEVFREQ_GOV_STOP:
gov_stop(df);
dev_dbg(df->dev.parent,
"Disabled dev BW HW monitor governor\n");
break;
case DEVFREQ_GOV_INTERVAL:
sample_ms = *(unsigned int *)data;
sample_ms = max(MIN_MS, sample_ms);
sample_ms = min(MAX_MS, sample_ms);
/*
* Suspend/resume the HW monitor around the interval update
* to prevent the HW monitor IRQ from trying to change
* stop/start the delayed workqueue while the interval update
* is happening.
*/
node = df->data;
hw = node->hw;
hw->suspend_hwmon(hw);
devfreq_interval_update(df, &sample_ms);
ret = hw->resume_hwmon(hw);
if (ret) {
dev_err(df->dev.parent,
"Unable to resume HW monitor (%d)\n", ret);
goto out;
}
break;
case DEVFREQ_GOV_SUSPEND:
ret = gov_suspend(df);
if (ret) {
dev_err(df->dev.parent,
"Unable to suspend BW HW mon governor (%d)\n",
ret);
goto out;
}
dev_dbg(df->dev.parent, "Suspended BW HW mon governor\n");
break;
case DEVFREQ_GOV_RESUME:
ret = gov_resume(df);
if (ret) {
dev_err(df->dev.parent,
"Unable to resume BW HW mon governor (%d)\n",
ret);
goto out;
}
dev_dbg(df->dev.parent, "Resumed BW HW mon governor\n");
break;
}
out:
mutex_unlock(&state_lock);
return ret;
}
static struct devfreq_governor devfreq_gov_bw_hwmon = {
.name = "bw_hwmon",
.get_target_freq = devfreq_bw_hwmon_get_freq,
.event_handler = devfreq_bw_hwmon_ev_handler,
};
int register_bw_hwmon(struct device *dev, struct bw_hwmon *hwmon)
{
int ret = 0;
struct hwmon_node *node;
struct attribute_group *attr_grp;
if (!hwmon->gov && !hwmon->dev && !hwmon->of_node)
return -EINVAL;
node = devm_kzalloc(dev, sizeof(*node), GFP_KERNEL);
if (!node)
return -ENOMEM;
if (hwmon->gov) {
attr_grp = devm_kzalloc(dev, sizeof(*attr_grp), GFP_KERNEL);
if (!attr_grp)
return -ENOMEM;
hwmon->gov->get_target_freq = devfreq_bw_hwmon_get_freq;
hwmon->gov->event_handler = devfreq_bw_hwmon_ev_handler;
attr_grp->name = hwmon->gov->name;
attr_grp->attrs = dev_attr;
node->gov = hwmon->gov;
node->attr_grp = attr_grp;
} else {
node->gov = &devfreq_gov_bw_hwmon;
node->attr_grp = &dev_attr_group;
}
node->guard_band_mbps = 100;
node->decay_rate = 90;
node->io_percent = 16;
node->bw_step = 190;
node->sample_ms = 50;
node->up_scale = 0;
node->up_thres = 10;
node->down_thres = 0;
node->down_count = 3;
node->hist_memory = 0;
node->hyst_trigger_count = 3;
node->hyst_length = 0;
node->idle_mbps = 400;
node->mbps_zones[0] = 0;
node->hw = hwmon;
mutex_lock(&list_lock);
list_add_tail(&node->list, &hwmon_list);
mutex_unlock(&list_lock);
if (hwmon->gov) {
ret = devfreq_add_governor(hwmon->gov);
} else {
mutex_lock(&state_lock);
if (!use_cnt)
ret = devfreq_add_governor(&devfreq_gov_bw_hwmon);
if (!ret)
use_cnt++;
mutex_unlock(&state_lock);
}
if (!ret)
dev_info(dev, "BW HWmon governor registered.\n");
else
dev_err(dev, "BW HWmon governor registration failed!\n");
return ret;
}
MODULE_DESCRIPTION("HW monitor based dev DDR bandwidth voting driver");
MODULE_LICENSE("GPL v2");