On Wednesday, July 08, 2015 04:07:32 PM Viresh Kumar wrote: > CPUFreq drivers today support a ->get(cpu) callback, which returns > current rate of a CPU. The problem with ->get() is that it takes a cpu > number as parameter and this unnecessarily makes things complex. > > Firstly the core gets the cpu number by doing operation 'policy->cpu' on > the policy and then many drivers need to get the policy back and so do > cpufreq_cpu_get(cpu) on the passed cpu. > > As cpufreq core works on policies, it would be better if we pass them > 'policy' directly and drivers can use policy->cpu if that's all they > need. > > Hence, this patch adds in another callback, ->get_rate() which does > exactly the same work as ->get(), just that we pass 'policy' as > parameter instead of 'cpu'. > > The plan is to migrate all drivers to this new callback and remove > ->get() after that. > > Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org> > --- > Hi Rafael, > > I hope you are fine with this stuff :), once you approve I will get > other patches to migrate existing drivers to this interface.
I'm generally fine with it, but please target it at 4.4 at the earliest. > drivers/cpufreq/cpufreq.c | 50 > ++++++++++++++++++++++++++++++++--------------- > include/linux/cpufreq.h | 1 + > 2 files changed, 35 insertions(+), 16 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index b612411655f9..b66e169601e8 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -154,6 +154,20 @@ void disable_cpufreq(void) > } > static DEFINE_MUTEX(cpufreq_governor_mutex); > > +/* Operations for ->get() and ->get_rate() operations */ > +static inline bool driver_supports_get_rate(void) > +{ > + return cpufreq_driver->get || cpufreq_driver->get_rate; > +} > + > +static inline unsigned int policy_get_rate(struct cpufreq_policy *policy) > +{ > + if (cpufreq_driver->get) > + return cpufreq_driver->get(policy->cpu); > + else > + return cpufreq_driver->get_rate(policy); > +} > + > bool have_governor_per_policy(void) > { > return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY); > @@ -596,8 +610,9 @@ static ssize_t show_scaling_cur_freq(struct > cpufreq_policy *policy, char *buf) > { > ssize_t ret; > > - if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) > - ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu)); > + if (cpufreq_driver && cpufreq_driver->setpolicy && > + driver_supports_get_rate()) > + ret = sprintf(buf, "%u\n", policy_get_rate(policy)); > else > ret = sprintf(buf, "%u\n", policy->cur); > return ret; > @@ -1032,7 +1047,7 @@ static int cpufreq_add_dev_interface(struct > cpufreq_policy *policy, > return ret; > drv_attr++; > } > - if (cpufreq_driver->get) { > + if (driver_supports_get_rate()) { > ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); > if (ret) > return ret; > @@ -1313,10 +1328,10 @@ static int cpufreq_add_dev(struct device *dev, struct > subsys_interface *sif) > write_unlock_irqrestore(&cpufreq_driver_lock, flags); > } > > - if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { > - policy->cur = cpufreq_driver->get(policy->cpu); > + if (driver_supports_get_rate() && !cpufreq_driver->setpolicy) { > + policy->cur = policy_get_rate(policy); > if (!policy->cur) { > - pr_err("%s: ->get() failed\n", __func__); > + pr_err("%s: ->get_rate() failed\n", __func__); > goto err_get_freq; > } > } > @@ -1594,14 +1609,17 @@ unsigned int cpufreq_quick_get(unsigned int cpu) > struct cpufreq_policy *policy; > unsigned int ret_freq = 0; > > - if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) > - return cpufreq_driver->get(cpu); > - > policy = cpufreq_cpu_get(cpu); > - if (policy) { > + if (!policy) > + return 0; > + > + if (cpufreq_driver && cpufreq_driver->setpolicy && > + driver_supports_get_rate()) > + ret_freq = policy_get_rate(policy); > + else > ret_freq = policy->cur; > - cpufreq_cpu_put(policy); > - } > + > + cpufreq_cpu_put(policy); > > return ret_freq; > } > @@ -1631,10 +1649,10 @@ static unsigned int __cpufreq_get(struct > cpufreq_policy *policy) > { > unsigned int ret_freq = 0; > > - if (!cpufreq_driver->get) > + if (!driver_supports_get_rate()) > return ret_freq; > > - ret_freq = cpufreq_driver->get(policy->cpu); > + ret_freq = policy_get_rate(policy); > > /* Updating inactive policies is invalid, so avoid doing that. */ > if (unlikely(policy_is_inactive(policy))) > @@ -2345,8 +2363,8 @@ int cpufreq_update_policy(unsigned int cpu) > * BIOS might change freq behind our back > * -> ask driver for current freq and notify governors about a change > */ > - if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { > - new_policy.cur = cpufreq_driver->get(cpu); > + if (driver_supports_get_rate() && !cpufreq_driver->setpolicy) { > + new_policy.cur = policy_get_rate(policy); > if (WARN_ON(!new_policy.cur)) { > ret = -EIO; > goto unlock; > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > index 29ad97c34fd5..a82049683016 100644 > --- a/include/linux/cpufreq.h > +++ b/include/linux/cpufreq.h > @@ -263,6 +263,7 @@ struct cpufreq_driver { > > /* should be defined, if possible */ > unsigned int (*get)(unsigned int cpu); > + unsigned int (*get_rate)(struct cpufreq_policy *policy); > > /* optional */ > int (*bios_limit)(int cpu, unsigned int *limit); > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/