Re: [PATCH 08/17] PM / OPP: Add dev_pm_opp_set_rate()
From: Stephen Boyd <hidden>
Date: 2016-01-12 01:40:13
On 12/22, Viresh Kumar wrote:
quoted hunk ↗ jump to hunk
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c index 1d1b0faa825d..c76818f69f14 100644 --- a/drivers/base/power/opp/core.c +++ b/drivers/base/power/opp/core.c@@ -517,6 +517,148 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, } EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor); +/* + * _set_opp_voltage() - Configure device supply for an OPP + * @dev: device for which we do this operation + * @dev_opp: dev_opp for the device + * @opp: opp for getting supply voltage levels + * + * This is used to configure the power supply, used by the device, to the + * voltage levels specified by a particular OPP. + */ +static int _set_opp_voltage(struct device *dev, struct device_opp *dev_opp, + struct dev_pm_opp *opp) +{ + struct regulator *reg = dev_opp->regulator; + int ret; + + /* Regulator not be available for device */ + if (IS_ERR(reg)) { + dev_dbg(dev, "%s: regulator not available: %ld\n", __func__, + PTR_ERR(reg)); + return 0; + } + + dev_dbg(dev, "%s: voltages (mV): %lu %lu %lu\n", __func__, + opp->u_volt_min, opp->u_volt, opp->u_volt_max); + + ret = regulator_set_voltage_triplet(reg, opp->u_volt_min, opp->u_volt,
This can't be called under an RCU read lock.
+ opp->u_volt_max);
+ if (ret)
+ dev_err(dev, "%s: failed to set voltage (%lu %lu %lu mV): %d\n",
+ __func__, opp->u_volt_min, opp->u_volt, opp->u_volt_max,
+ ret);
+
+ return ret;
+}
+
+/**
+ * dev_pm_opp_set_rate() - Configure new OPP based on frequency
+ * @dev: device for which we do this operation
+ * @target_freq: frequency to achieve
+ *
+ * This configures the power-supplies and clock source to the levels specified
+ * by the OPP corresponding to the target_freq. It takes all necessary locks
+ * required for the operation and the caller doesn't need to care about the rcu
+ * locks.
+ */
+int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
+{
+ struct device_opp *dev_opp;
+ struct dev_pm_opp *old_opp, *opp;
+ struct clk *clk;
+ unsigned long freq, old_freq;
+ int ret;
+
+ if (unlikely(!target_freq)) {
+ dev_err(dev, "%s: Invalid target frequemncy %lu\n", __func__,s/frequemncy/frequency/
+ target_freq); + return -EINVAL; + } + + rcu_read_lock();
This lock is held way too long.
+
+ dev_opp = _find_device_opp(dev);
+ if (IS_ERR(dev_opp)) {
+ dev_err(dev, "%s: device opp doesn't exist\n", __func__);
+ ret = PTR_ERR(dev_opp);
+ goto unlock;
+ }
+
+ clk = dev_opp->clk;
+ if (IS_ERR(clk)) {
+ dev_err(dev, "%s: No clock available for the device\n",
+ __func__);
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ freq = clk_round_rate(clk, target_freq);This can't be called under RCU.
+ if ((long)freq <= 0) + freq = target_freq; + + old_freq = clk_get_rate(clk);
Same for this.
+
+ /* Return early if nothing to do */
+ if (old_freq == freq) {
+ dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
+ __func__, freq);
+ ret = 0;
+ goto unlock;
+ }
+
+ old_opp = dev_pm_opp_find_freq_ceil(dev, &old_freq);
+ opp = dev_pm_opp_find_freq_ceil(dev, &freq);
+
+ if (IS_ERR(opp)) {
+ ret = PTR_ERR(opp);
+ dev_err(dev, "%s: failed to find OPP for freq %lu (%d)\n",
+ __func__, freq, ret);
+ goto unlock;
+ }
+
+ /* Scaling up? Scale voltage before frequency */
+ if (freq > old_freq) {
+ ret = _set_opp_voltage(dev, dev_opp, opp);
+ if (ret)
+ goto restore_voltage;
+ }
+
+ /* Change frequency */
+
+ dev_dbg(dev, "%s: switching OPP: %lu Hz --> %lu Hz\n",
+ __func__, old_freq, freq);
+
+ ret = clk_set_rate(clk, freq);And same for this. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project