lkml.org 
[lkml]   [2016]   [Jul]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit
Date
In dev_pm_opp_set_rate(), _find_opp_table() is called three times: once
by _get_opp_clk(), twice by dev_pm_opp_find_freq_ceil(). If there are
several opp_tables in the system, three times of opp table finding is a
big waste. This patch reduced the call of _find_opp_table() to only
once.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
drivers/base/power/opp/core.c | 85 ++++++++++++++++++-------------------------
1 file changed, 36 insertions(+), 49 deletions(-)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 7c04c87..96043ee 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -402,6 +402,22 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);

+static struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
+ unsigned long *freq)
+{
+ struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
+
+ list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
+ if (temp_opp->available && temp_opp->rate >= *freq) {
+ opp = temp_opp;
+ *freq = opp->rate;
+ break;
+ }
+ }
+
+ return opp;
+}
+
/**
* dev_pm_opp_find_freq_ceil() - Search for an rounded ceil freq
* @dev: device for which we do this operation
@@ -427,7 +443,6 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
unsigned long *freq)
{
struct opp_table *opp_table;
- struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);

opp_rcu_lockdep_assert();

@@ -440,15 +455,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
if (IS_ERR(opp_table))
return ERR_CAST(opp_table);

- list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
- if (temp_opp->available && temp_opp->rate >= *freq) {
- opp = temp_opp;
- *freq = opp->rate;
- break;
- }
- }
-
- return opp;
+ return _find_freq_ceil(opp_table, freq);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);

@@ -506,34 +513,6 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);

-/*
- * The caller needs to ensure that opp_table (and hence the clk) isn't freed,
- * while clk returned here is used.
- */
-static struct clk *_get_opp_clk(struct device *dev)
-{
- struct opp_table *opp_table;
- struct clk *clk;
-
- rcu_read_lock();
-
- opp_table = _find_opp_table(dev);
- if (IS_ERR(opp_table)) {
- dev_err(dev, "%s: device opp doesn't exist\n", __func__);
- clk = ERR_CAST(opp_table);
- goto unlock;
- }
-
- clk = opp_table->clk;
- if (IS_ERR(clk))
- dev_err(dev, "%s: No clock available for the device\n",
- __func__);
-
-unlock:
- rcu_read_unlock();
- return clk;
-}
-
static int _set_opp_voltage(struct device *dev, struct regulator *reg,
unsigned long u_volt, unsigned long u_volt_min,
unsigned long u_volt_max)
@@ -586,9 +565,24 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
return -EINVAL;
}

- clk = _get_opp_clk(dev);
- if (IS_ERR(clk))
+ rcu_read_lock();
+
+ opp_table = _find_opp_table(dev);
+ if (IS_ERR(opp_table)) {
+ dev_err(dev, "%s: device opp doesn't exist\n", __func__);
+ rcu_read_unlock();
+ return PTR_ERR(opp_table);
+ }
+
+ clk = opp_table->clk;
+ if (IS_ERR(clk)) {
+ dev_err(dev, "%s: No clock available for the device\n",
+ __func__);
+ rcu_read_unlock();
return PTR_ERR(clk);
+ }
+
+ rcu_read_unlock();

freq = clk_round_rate(clk, target_freq);
if ((long)freq <= 0)
@@ -605,14 +599,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)

rcu_read_lock();

- opp_table = _find_opp_table(dev);
- if (IS_ERR(opp_table)) {
- dev_err(dev, "%s: device opp doesn't exist\n", __func__);
- rcu_read_unlock();
- return PTR_ERR(opp_table);
- }
-
- old_opp = dev_pm_opp_find_freq_ceil(dev, &old_freq);
+ old_opp = _find_freq_ceil(opp_table, &old_freq);
if (!IS_ERR(old_opp)) {
ou_volt = old_opp->u_volt;
ou_volt_min = old_opp->u_volt_min;
@@ -622,7 +609,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
__func__, old_freq, PTR_ERR(old_opp));
}

- opp = dev_pm_opp_find_freq_ceil(dev, &freq);
+ opp = _find_freq_ceil(opp_table, &freq);
if (IS_ERR(opp)) {
ret = PTR_ERR(opp);
dev_err(dev, "%s: failed to find OPP for freq %lu (%d)\n",
--
2.8.1
\
 
 \ /
  Last update: 2016-07-22 15:21    [W:0.110 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site