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Subject[PATCH 2/2] devfreq: Rename df->previous_freq to df->cur_freq
Date
The vast majority of code uses df->previous_freq to get the current
frequency of the devfreq device, not the previous one. Rename the
struct field to reflect this.

Add a comment to devfreq_update_stats() to make clear that df->cur_freq
must only be updated after calling this function in the context of a
frequency transition.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---
drivers/devfreq/devfreq.c | 28 ++++++++++++++++------------
drivers/devfreq/governor_passive.c | 6 +++---
drivers/devfreq/governor_userspace.c | 2 +-
drivers/devfreq/tegra20-devfreq.c | 2 +-
drivers/devfreq/tegra30-devfreq.c | 2 +-
include/linux/devfreq.h | 4 ++--
include/trace/events/devfreq.h | 2 +-
7 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index fb4318d59aa9..bf42130bb4ec 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -154,6 +154,10 @@ static int set_freq_table(struct devfreq *devfreq)
* devfreq_update_stats() - Update statistics of devfreq behavior
* @devfreq: the devfreq instance
* @freq: the update target frequency
+ *
+ * If the function is called in the context of a frequency transition
+ * it expects df->cur_freq to contain the value *before* the transition.
+ * The field must only be updated after calling devfreq_update_stats().
*/
int devfreq_update_stats(struct devfreq *devfreq, unsigned long freq)
{
@@ -162,11 +166,11 @@ int devfreq_update_stats(struct devfreq *devfreq, unsigned long freq)

cur_time = jiffies;

- /* Immediately exit if previous_freq is not initialized yet. */
- if (!devfreq->previous_freq)
+ /* Immediately exit if cur_freq is not initialized yet. */
+ if (!devfreq->cur_freq)
goto out;

- prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
+ prev_lev = devfreq_get_freq_level(devfreq, devfreq->cur_freq);
if (prev_lev < 0) {
ret = prev_lev;
goto out;
@@ -295,7 +299,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
if (devfreq->profile->get_cur_freq)
devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
else
- cur_freq = devfreq->previous_freq;
+ cur_freq = devfreq->cur_freq;

freqs.old = cur_freq;
freqs.new = new_freq;
@@ -315,7 +319,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
dev_err(&devfreq->dev,
"Couldn't update frequency transition information.\n");

- devfreq->previous_freq = new_freq;
+ devfreq->cur_freq = new_freq;

if (devfreq->suspend_freq)
devfreq->resume_freq = cur_freq;
@@ -450,7 +454,7 @@ void devfreq_monitor_suspend(struct devfreq *devfreq)
return;
}

- devfreq_update_stats(devfreq, devfreq->previous_freq);
+ devfreq_update_stats(devfreq, devfreq->cur_freq);
devfreq->stop_polling = true;
mutex_unlock(&devfreq->lock);
cancel_delayed_work_sync(&devfreq->work);
@@ -483,7 +487,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)

if (devfreq->profile->get_cur_freq &&
!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
- devfreq->previous_freq = freq;
+ devfreq->cur_freq = freq;

out:
mutex_unlock(&devfreq->lock);
@@ -644,7 +648,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
devfreq->dev.release = devfreq_dev_release;
devfreq->profile = profile;
strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
- devfreq->previous_freq = profile->initial_freq;
+ devfreq->cur_freq = profile->initial_freq;
devfreq->last_status.current_frequency = profile->initial_freq;
devfreq->data = data;
devfreq->nb.notifier_call = devfreq_notifier_call;
@@ -1235,14 +1239,14 @@ static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
return sprintf(buf, "%lu\n", freq);

- return sprintf(buf, "%lu\n", devfreq->previous_freq);
+ return sprintf(buf, "%lu\n", devfreq->cur_freq);
}
static DEVICE_ATTR_RO(cur_freq);

static ssize_t target_freq_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
+ return sprintf(buf, "%lu\n", to_devfreq(dev)->cur_freq);
}
static DEVICE_ATTR_RO(target_freq);

@@ -1398,7 +1402,7 @@ static ssize_t trans_stat_show(struct device *dev,
unsigned int max_state = devfreq->profile->max_state;

if (!devfreq->stop_polling &&
- devfreq_update_stats(devfreq, devfreq->previous_freq))
+ devfreq_update_stats(devfreq, devfreq->cur_freq))
return 0;
if (max_state == 0)
return sprintf(buf, "Not Supported.\n");
@@ -1413,7 +1417,7 @@ static ssize_t trans_stat_show(struct device *dev,

for (i = 0; i < max_state; i++) {
if (devfreq->profile->freq_table[i]
- == devfreq->previous_freq) {
+ == devfreq->cur_freq) {
len += sprintf(buf + len, "*");
} else {
len += sprintf(buf + len, " ");
diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
index 1c746b96d3db..2d818eaceb39 100644
--- a/drivers/devfreq/governor_passive.c
+++ b/drivers/devfreq/governor_passive.c
@@ -114,7 +114,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
dev_err(&devfreq->dev,
"Couldn't update frequency transition information.\n");

- devfreq->previous_freq = freq;
+ devfreq->cur_freq = freq;

out:
mutex_unlock(&devfreq->lock);
@@ -134,11 +134,11 @@ static int devfreq_passive_notifier_call(struct notifier_block *nb,

switch (event) {
case DEVFREQ_PRECHANGE:
- if (parent->previous_freq > freq)
+ if (parent->cur_freq > freq)
update_devfreq_passive(devfreq, freq);
break;
case DEVFREQ_POSTCHANGE:
- if (parent->previous_freq < freq)
+ if (parent->cur_freq < freq)
update_devfreq_passive(devfreq, freq);
break;
}
diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
index af94942fcf95..566b8d1f0c17 100644
--- a/drivers/devfreq/governor_userspace.c
+++ b/drivers/devfreq/governor_userspace.c
@@ -26,7 +26,7 @@ static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
if (data->valid)
*freq = data->user_frequency;
else
- *freq = df->previous_freq; /* No user freq specified yet */
+ *freq = df->cur_freq; /* No user freq specified yet */

return 0;
}
diff --git a/drivers/devfreq/tegra20-devfreq.c b/drivers/devfreq/tegra20-devfreq.c
index ff82bac9ee4e..f99bd6557df5 100644
--- a/drivers/devfreq/tegra20-devfreq.c
+++ b/drivers/devfreq/tegra20-devfreq.c
@@ -61,7 +61,7 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
return 0;

restore_min_rate:
- clk_set_min_rate(tegra->emc_clock, devfreq->previous_freq);
+ clk_set_min_rate(tegra->emc_clock, devfreq->cur_freq);

return err;
}
diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
index 536273a811fe..7b3bf7a0b15f 100644
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -474,7 +474,7 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
return 0;

restore_min_rate:
- clk_set_min_rate(tegra->emc_clock, devfreq->previous_freq);
+ clk_set_min_rate(tegra->emc_clock, devfreq->cur_freq);

return err;
}
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 2bae9ed3c783..21d0108df4c5 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -120,7 +120,7 @@ struct devfreq_dev_profile {
* reevaluate operable frequencies. Devfreq users may use
* devfreq.nb to the corresponding register notifier call chain.
* @work: delayed work for load monitoring.
- * @previous_freq: previously configured frequency value.
+ * @cur_freq: the current frequency.
* @data: Private data of the governor. The devfreq framework does not
* touch this.
* @min_freq: Limit minimum frequency requested by user (0: none)
@@ -156,7 +156,7 @@ struct devfreq {
struct notifier_block nb;
struct delayed_work work;

- unsigned long previous_freq;
+ unsigned long cur_freq;
struct devfreq_dev_status last_status;

void *data; /* private data for governors */
diff --git a/include/trace/events/devfreq.h b/include/trace/events/devfreq.h
index cf5b8772175d..916cfaed5489 100644
--- a/include/trace/events/devfreq.h
+++ b/include/trace/events/devfreq.h
@@ -22,7 +22,7 @@ TRACE_EVENT(devfreq_monitor,
),

TP_fast_assign(
- __entry->freq = devfreq->previous_freq;
+ __entry->freq = devfreq->cur_freq;
__entry->busy_time = devfreq->last_status.busy_time;
__entry->total_time = devfreq->last_status.total_time;
__entry->polling_ms = devfreq->profile->polling_ms;
--
2.23.0.444.g18eeb5a265-goog
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