Messages in this thread Patch in this message | | | Date | Mon, 19 Dec 2022 17:38:59 -0600 | Subject | Re: [PATCH v8 09/13] cpufreq: amd-pstate: add driver working mode switch support | From | "Limonciello, Mario" <> |
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On 12/19/2022 00:40, Perry Yuan wrote: > From: Perry Yuan <Perry.Yuan@amd.com> > > While amd-pstate driver was loaded with specific driver mode, it will > need to check which mode is enabled for the pstate driver,add this sysfs > entry to show the current status > > $ cat /sys/devices/system/cpu/amd-pstate/status > active > > Meanwhile, user can switch the pstate driver mode with writing mode > string to sysfs entry as below. > > Enable passive mode: > $ sudo bash -c "echo passive > /sys/devices/system/cpu/amd-pstate/status" > > Enable active mode (EPP driver mode): > $ sudo bash -c "echo active > /sys/devices/system/cpu/amd-pstate/status" > > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com> > --- > drivers/cpufreq/amd-pstate.c | 128 +++++++++++++++++++++++++++++++++++ > 1 file changed, 128 insertions(+) > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index fc12d35bc7bd..e8996e937e63 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -64,6 +64,7 @@ static struct cpufreq_driver amd_pstate_driver; > static struct cpufreq_driver amd_pstate_epp_driver; > static struct amd_cpudata **all_cpu_data; > static int cppc_state = AMD_PSTATE_DISABLE; > +struct kobject *amd_pstate_kobj; > > static inline int get_mode_idx_from_str(const char *str, size_t size) > { > @@ -90,6 +91,8 @@ static struct amd_pstate_params global_params; > static DEFINE_MUTEX(amd_pstate_limits_lock); > static DEFINE_MUTEX(amd_pstate_driver_lock); > > +static DEFINE_SPINLOCK(cppc_notify_lock); > + > static s16 amd_pstate_get_epp(struct amd_cpudata *cpudata, u64 cppc_req_cached) > { > u64 epp; > @@ -644,6 +647,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy) > policy->driver_data = cpudata; > > amd_pstate_boost_init(cpudata); > + if (!default_pstate_driver->adjust_perf) > + default_pstate_driver->adjust_perf = amd_pstate_adjust_perf; > > return 0; > > @@ -784,12 +789,106 @@ static ssize_t show_energy_performance_preference( > return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]); > } > > +static ssize_t amd_pstate_show_status(char *buf) > +{ > + if (!default_pstate_driver) > + return sysfs_emit(buf, "off\n"); > + > + return sysfs_emit(buf, "%s\n", default_pstate_driver == &amd_pstate_epp_driver ? > + "active" : "passive");
Didn't you introduce const strings for this in an earlier patch from the series?
How about using the indices from that rather than hardcoding /another/ string.
Also keep in mind guided mode will be coming so "case ? true_val : false_val"
So perhaps you should just have have some if cases so you don't have to switch the whole thing out.
> +} > + > +static void amd_pstate_driver_cleanup(void) > +{ > + unsigned int cpu; > + > + cpus_read_lock(); > + for_each_online_cpu(cpu) { > + if (all_cpu_data[cpu]) { > + spin_lock(&cppc_notify_lock); > + kfree(all_cpu_data[cpu]); > + WRITE_ONCE(all_cpu_data[cpu], NULL); > + spin_unlock(&cppc_notify_lock); > + } > + } > + cpus_read_unlock(); > + > + default_pstate_driver = NULL; > +} > + > +static int amd_pstate_update_status(const char *buf, size_t size) > +{
Rather than looking at each size for each case, how about you just look at the boundaries once? Something like this:
if (size > 7 || size < 3) return -EINVAL;
Then you should be able to run strncmp for each of your cases.
> + if (size == 3 && !strncmp(buf, "off", size)) {
This seems like another case that would be good to use the const strings you already introduced for state machine checking.
> + if (!default_pstate_driver) > + return -EINVAL; > + > + if (cppc_state == AMD_PSTATE_ACTIVE) > + return -EBUSY; > + > + cpufreq_unregister_driver(default_pstate_driver); > + amd_pstate_driver_cleanup(); > + return 0; > + } > + > + if (size == 6 && !strncmp(buf, "active", size)) {
This seems like another case that would be good to use the const strings you already introduced for state machine checking.
> + if (default_pstate_driver) { > + if (default_pstate_driver == &amd_pstate_epp_driver) > + return 0; > + cpufreq_unregister_driver(default_pstate_driver); > + default_pstate_driver = &amd_pstate_epp_driver; > + cppc_state = AMD_PSTATE_ACTIVE; > + } > + > + return cpufreq_register_driver(default_pstate_driver); > + } > + > + if (size == 7 && !strncmp(buf, "passive", size)) {
This seems like another case that would be good to use the const strings you already introduced for state machine checking.
> + if (default_pstate_driver) { > + if (default_pstate_driver == &amd_pstate_driver) > + return 0; > + cpufreq_unregister_driver(default_pstate_driver); > + cppc_state = AMD_PSTATE_PASSIVE; > + default_pstate_driver = &amd_pstate_driver; > + } > + > + return cpufreq_register_driver(default_pstate_driver); > + } > + > + return -EINVAL; > +} > + > +static ssize_t show_status(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + ssize_t ret; > + > + mutex_lock(&amd_pstate_driver_lock); > + ret = amd_pstate_show_status(buf); > + mutex_unlock(&amd_pstate_driver_lock); > + > + return ret; > +} > + > +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b, > + const char *buf, size_t count) > +{ > + char *p = memchr(buf, '\n', count); > + int ret; > + > + mutex_lock(&amd_pstate_driver_lock); > + ret = amd_pstate_update_status(buf, p ? p - buf : count); > + mutex_unlock(&amd_pstate_driver_lock); > + > + return ret < 0 ? ret : count; > +} > + > cpufreq_freq_attr_ro(amd_pstate_max_freq); > cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq); > > cpufreq_freq_attr_ro(amd_pstate_highest_perf); > cpufreq_freq_attr_rw(energy_performance_preference); > cpufreq_freq_attr_ro(energy_performance_available_preferences); > +define_one_global_rw(status); > > static struct freq_attr *amd_pstate_attr[] = { > &amd_pstate_max_freq, > @@ -807,6 +906,15 @@ static struct freq_attr *amd_pstate_epp_attr[] = { > NULL, > }; > > +static struct attribute *pstate_global_attributes[] = { > + &status.attr, > + NULL > +}; > + > +static const struct attribute_group amd_pstate_global_attr_group = { > + .attrs = pstate_global_attributes, > +}; > + > static inline void update_boost_state(void) > { > u64 misc_en; > @@ -1228,6 +1336,26 @@ static int __init amd_pstate_init(void) > if (ret) > pr_err("failed to register with return %d\n", ret); > > + amd_pstate_kobj = kobject_create_and_add("amd-pstate", &cpu_subsys.dev_root->kobj); > + if (!amd_pstate_kobj) { > + ret = -EINVAL; > + pr_err("global sysfs registration failed.\n"); > + goto kobject_free; > + } > + > + ret = sysfs_create_group(amd_pstate_kobj, &amd_pstate_global_attr_group); > + if (ret) { > + pr_err("sysfs attribute export failed with error %d.\n", ret); > + goto global_attr_free; > + } > + > + return ret; > + > +global_attr_free: > + kobject_put(amd_pstate_kobj); > +kobject_free: > + kfree(cpudata); > + cpufreq_unregister_driver(default_pstate_driver); > return ret; > } > device_initcall(amd_pstate_init);
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