RE: [PATCH v3 4/8] cpufreq: amd_pstate: add AMD Pstate EPP support for the MSR based processors
From: Yuan, Perry
Date: Thu Nov 10 2022 - 11:22:14 EST
[AMD Official Use Only - General]
Hi Nathan.
> -----Original Message-----
> From: Fontenot, Nathan <Nathan.Fontenot@xxxxxxx>
> Sent: Friday, November 11, 2022 12:00 AM
> To: Limonciello, Mario <Mario.Limonciello@xxxxxxx>; Yuan, Perry
> <Perry.Yuan@xxxxxxx>; rafael.j.wysocki@xxxxxxxxx; Huang, Ray
> <Ray.Huang@xxxxxxx>; viresh.kumar@xxxxxxxxxx
> Cc: Sharma, Deepak <Deepak.Sharma@xxxxxxx>; Deucher, Alexander
> <Alexander.Deucher@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>; Du, Xiaojian <Xiaojian.Du@xxxxxxx>; Meng,
> Li (Jassmine) <Li.Meng@xxxxxxx>; linux-pm@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3 4/8] cpufreq: amd_pstate: add AMD Pstate EPP
> support for the MSR based processors
>
>
>
> On 11/7/22 14:32, Limonciello, Mario wrote:
> > On 11/7/2022 11:57, Perry Yuan wrote:
> >> Add EPP driver support for those AMD CPUs which has full MSR feature
> >> enabled, The EPP is used in the DPM controller to drive the frequency
> >> that a core is going to operate during short periods of activity.
> >
> > To avoid the run on sentence, here is a different wording proposal.
> >
> > Add EPP driver support for AMD SoCs which support a dedicated MSR for
> CPPC. EPP is used by the DPM controller to configure the frequency that a
> core operates at during short periods of activity.
> >
> >>
> >> EPP values will be utilized for different OS profiles (balanced,
> >> performance, power savings). cppc performance can be controlled by
> >> the user space interface sys attributes for min and max frequency
> >> limits, when pstate driver is working under power save policy.
> >>
> >> EPP scale is 0 - 255, 0 is the max performance and 255 is min level.
> >> balance_performance (0x80) can provide best balance performance and
> >> watt for most of system, meanwhile user can choose performance policy
> on needs.
> >
> > As a user reading this message it is confusing that there are values and then
> there are strings, but you don't know the linkage between the two. My
> proposal for rewording this:
> >
> > The SoC EPP targets are configured on a scale from 0 to 255 where 0
> represents maximum performance and 255 represents maximum efficiency.
> >
> > The amd-pstate driver exports profile string names to userspace that are
> tied to specific EPP values.
> >
> > The balance_performance string (0x80) provides the best balance for
> efficiency versus power on most systems, but users can choose other strings
> to meet their needs as well.
> >
> >>
> >> $ cat
> >>
> /sys/devices/system/cpu/cpufreq/policy0/energy_performance_available_
> >> preferences default performance balance_performance balance_power
> >> power
> >>
> >> $ cat
> >>
> /sys/devices/system/cpu/cpufreq/policy0/energy_performance_preferenc
> e
> >> balance_performance
> >>
> >> Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
> >> ---
> >> drivers/cpufreq/amd-pstate.c | 658
> >> ++++++++++++++++++++++++++++++++++-
> >> include/linux/amd-pstate.h | 81 +++++
> >> 2 files changed, 734 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/cpufreq/amd-pstate.c
> >> b/drivers/cpufreq/amd-pstate.c index 14906431dc15..eb82bc6a7f66
> >> 100644
> >> --- a/drivers/cpufreq/amd-pstate.c
> >> +++ b/drivers/cpufreq/amd-pstate.c
> >> @@ -60,8 +60,136 @@
> >> * module parameter to be able to enable it manually for debugging.
> >> */
> >> static bool shared_mem __read_mostly;
> >> +static int cppc_active __read_mostly; static int disable_pstate_load
> >> +__initdata; static int epp_off __initdata;
> >> -static struct cpufreq_driver amd_pstate_driver;
> >> +static struct cpufreq_driver *default_pstate_driver; static struct
> >> +amd_cpudata **all_cpu_data;
> >> +
> >> +static struct amd_pstate_params global_params;
> >> +
> >> +static DEFINE_MUTEX(amd_pstate_limits_lock);
> >> +static DEFINE_MUTEX(amd_pstate_driver_lock);
> >> +
> >> +static bool cppc_boost __read_mostly; struct kobject
> >> +*amd_pstate_kobj;
> >> +
> >> +#ifdef CONFIG_ACPI_CPPC_LIB
> >> +static s16 amd_pstate_get_epp(struct amd_cpudata *cpudata, u64
> >> +cppc_req_cached) {
> >> + s16 epp;
> >> + struct cppc_perf_caps perf_caps;
> >> + int ret;
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + if (!cppc_req_cached) {
> >> + epp = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
> >> + &cppc_req_cached);
> >> + if (epp)
> >> + return epp;
> >> + }
> >> + epp = (cppc_req_cached >> 24) & 0xFF;
> >> + } else {
> >> + ret = cppc_get_epp_caps(cpudata->cpu, &perf_caps);
> >> + if (ret < 0) {
> >> + pr_debug("Could not retrieve energy perf value (%d)\n",
> >> +ret);
> >> + return -EIO;
> >> + }
> >> + epp = (s16) perf_caps.energy_perf;
> >> + }
> >> +
> >> + return epp;
> >> +}
> >> +#endif
> >> +
> >> +static int amd_pstate_get_energy_pref_index(struct amd_cpudata
> >> +*cpudata, int *raw_epp) {
> >> + s16 epp;
> >> + int index = -EINVAL;
> >> +
> >> + *raw_epp = 0;
> >> + epp = amd_pstate_get_epp(cpudata, 0);
> >> + if (epp < 0)
> >> + return epp;
> >> +
> >> + switch (epp) {
> >> + case AMD_CPPC_EPP_PERFORMANCE:
> >> + index = EPP_INDEX_PERFORMANCE;
> >> + break;
> >> + case AMD_CPPC_EPP_BALANCE_PERFORMANCE:
> >> + index = EPP_INDEX_BALANCE_PERFORMANCE;
> >> + break;
> >> + case AMD_CPPC_EPP_BALANCE_POWERSAVE:
> >> + index = EPP_INDEX_BALANCE_POWERSAVE;
> >> + break;
> >> + case AMD_CPPC_EPP_POWERSAVE:
> >> + index = EPP_INDEX_POWERSAVE;
> >> + break;
> >> + default:
> >> + *raw_epp = epp;
> >> + index = 0;
> >> + }
> >> +
> >> + return index;
> >> +}
> >> +
> >> +#ifdef CONFIG_ACPI_CPPC_LIB
> >> +static int amd_pstate_set_epp(struct amd_cpudata *cpudata, u32 epp)
> >> +{
> >> + int ret;
> >> + struct cppc_perf_ctrls perf_ctrls;
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + u64 value = READ_ONCE(cpudata->cppc_req_cached);
> >> +
> >> + value &= ~GENMASK_ULL(31, 24);
> >> + value |= (u64)epp << 24;
> >> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> >> +
> >> + ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> >> + if (!ret)
> >> + cpudata->epp_cached = epp;
> >> + } else {
> >> + perf_ctrls.energy_perf = epp;
> >> + ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls);
> >> + if (ret) {
> >> + pr_debug("failed to set energy perf value (%d)\n", ret);
> >> + return ret;
> >> + }
> >> + cpudata->epp_cached = epp;
> >> + }
> >> +
> >> + return ret;
> >> +}
> >> +
> >> +static int amd_pstate_set_energy_pref_index(struct amd_cpudata
> >> +*cpudata,
> >> + int pref_index, bool use_raw,
> >> + u32 raw_epp) {
> >> + int epp = -EINVAL;
> >> + int ret;
> >> +
> >> + if (!pref_index) {
> >> + pr_debug("EPP pref_index is invalid\n");
> >> + return -EINVAL;
> >> + }
> >> +
> >> + if (use_raw)
> >> + epp = raw_epp;
> >> + else if (epp == -EINVAL)
> >> + epp = epp_values[pref_index];
> >> +
> >> + if (epp > 0 && cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
> >> + pr_debug("EPP cannot be set under performance policy\n");
> >> + return -EBUSY;
> >> + }
> >> +
> >> + ret = amd_pstate_set_epp(cpudata, epp);
> >> +
> >> + return ret;
> >> +}
> >> +#endif
> >> static inline int pstate_enable(bool enable)
> >> {
> >> @@ -71,11 +199,25 @@ static inline int pstate_enable(bool enable)
> >> static int cppc_enable(bool enable)
> >> {
> >> int cpu, ret = 0;
> >> + struct cppc_perf_ctrls perf_ctrls;
> >> for_each_present_cpu(cpu) {
> >> ret = cppc_set_enable(cpu, enable);
> >> if (ret)
> >> return ret;
> >> +
> >> + /* Enable autonomous mode for EPP */
> >> + if (!cppc_active) {
> >> + ret = cppc_set_auto_epp(cpu, enable);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + /* Set desired perf as zero to allow EPP firmware
> >> +control */
> >> + perf_ctrls.desired_perf = 0;
> >> + ret = cppc_set_perf(cpu, &perf_ctrls);
> >> + if (ret)
> >> + return ret;
> >> + }
> >> }
> >> return ret;
> >> @@ -418,7 +560,7 @@ static void amd_pstate_boost_init(struct
> >> amd_cpudata *cpudata)
> >> return;
> >> cpudata->boost_supported = true;
> >> - amd_pstate_driver.boost_enabled = true;
> >> + default_pstate_driver->boost_enabled = true;
> >> }
> >> static int amd_pstate_cpu_init(struct cpufreq_policy *policy) @@
> >> -582,10 +724,74 @@ static ssize_t show_amd_pstate_highest_perf(struct
> >> cpufreq_policy *policy,
> >> return sprintf(&buf[0], "%u\n", perf);
> >> }
> >> +static ssize_t show_energy_performance_available_preferences(
> >> + struct cpufreq_policy *policy, char *buf) {
> >> + int i = 0;
> >> + int ret = 0;
> >> +
> >> + while (energy_perf_strings[i] != NULL)
> >> + ret += sprintf(&buf[ret], "%s ", energy_perf_strings[i++]);
> >> +
> >> + ret += sprintf(&buf[ret], "\n");
> >> +
> >> + return ret;
> >> +}
> >> +
> >> +static ssize_t store_energy_performance_preference(
> >> + struct cpufreq_policy *policy, const char *buf, size_t
> >> +count) {
> >> + struct amd_cpudata *cpudata = policy->driver_data;
> >> + char str_preference[21];
> >> + bool raw = false;
> >> + ssize_t ret;
> >> + u32 epp = 0;
> >> +
> >> + ret = sscanf(buf, "%20s", str_preference);
> >> + if (ret != 1)
> >> + return -EINVAL;
> >> +
> >> + ret = match_string(energy_perf_strings, -1, str_preference);
> >> + if (ret < 0) {
> >> + ret = kstrtouint(buf, 10, &epp);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + if ((epp > 255) || (epp < 0))
> >> + return -EINVAL;
> >> +
> >> + raw = true;
> >> + }
> >
> > What's the reason for supporting putting the raw number in here for stuff
> "in between"? I think this is going to pretty confusing to userspace that you
> can use string values or integer values. It also means that if userspace writes
> an integer with a mapping to string and tries to read it back they'll get the
> string rather than the integer!
> >
> > I can understand using the raw values for internal characterization and
> development to possibly introduce a new mapping string, but I don't think
> that makes sense in the kernel.
> >
>
> This is really doing what Intel does for handling EPP settings. Yes, writing a
> value and getting back a string could be a bit confusing bit it is already done
> from the Intel side. I think keeping EPP value setting common would be a
> good thing if we can do it.
>
> I don't think we should remove the ability to set raw values, we're allowed a
> range of 0 - 255 for the EPP setting. Why we then limit ourselves to only 4 or
> so values?
>
> -Nathan
The raw values are userd for tunning , we have another utility to fine tune the performance/power under development.
So from the customer perspective, we do not need to keep the raw epp set any more in my opinion.
And Mario also has strong justification for the change.
Perry.
>
> >> +
> >> + mutex_lock(&amd_pstate_limits_lock);
> >> + ret = amd_pstate_set_energy_pref_index(cpudata, ret, raw, epp);
> >> + mutex_unlock(&amd_pstate_limits_lock);
> >> +
> >> + return ret ?: count;
> >> +}
> >> +
> >> +static ssize_t show_energy_performance_preference(
> >> + struct cpufreq_policy *policy, char *buf) {
> >> + struct amd_cpudata *cpudata = policy->driver_data;
> >> + int preference, raw_epp;
> >> +
> >> + preference = amd_pstate_get_energy_pref_index(cpudata,
> >> +&raw_epp);
> >> + if (preference < 0)
> >> + return preference;
> >> +
> >> + if (raw_epp)
> >> + return sprintf(buf, "%d\n", raw_epp);
> >> + else
> >> + return sprintf(buf, "%s\n",
> >> +energy_perf_strings[preference]); }
> >> +
> >> 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);
> >> static struct freq_attr *amd_pstate_attr[] = {
> >> &amd_pstate_max_freq,
> >> @@ -594,6 +800,415 @@ static struct freq_attr *amd_pstate_attr[] = {
> >> NULL,
> >> };
> >> +static struct freq_attr *amd_pstate_epp_attr[] = {
> >> + &amd_pstate_max_freq,
> >> + &amd_pstate_lowest_nonlinear_freq,
> >> + &amd_pstate_highest_perf,
> >> + &energy_performance_preference,
> >> + &energy_performance_available_preferences,
> >> + NULL,
> >> +};
> >> +
> >> +static inline void update_boost_state(void) {
> >> + u64 misc_en;
> >> + struct amd_cpudata *cpudata;
> >> +
> >> + cpudata = all_cpu_data[0];
> >> + rdmsrl(MSR_K7_HWCR, misc_en);
> >> + global_params.cppc_boost_disabled = misc_en & BIT_ULL(25); }
> >> +
> >> +static int amd_pstate_init_cpu(unsigned int cpunum) {
> >> + struct amd_cpudata *cpudata;
> >> +
> >> + cpudata = all_cpu_data[cpunum];
> >> + if (!cpudata) {
> >> + cpudata = kzalloc(sizeof(*cpudata), GFP_KERNEL);
> >> + if (!cpudata)
> >> + return -ENOMEM;
> >> + WRITE_ONCE(all_cpu_data[cpunum], cpudata);
> >> +
> >> + cpudata->cpu = cpunum;
> >> + }
> >> + cpudata->epp_powersave = -EINVAL;
> >> + cpudata->epp_policy = 0;
> >> + pr_debug("controlling: cpu %d\n", cpunum);
> >> + return 0;
> >> +}
> >> +
> >> +static int __amd_pstate_cpu_init(struct cpufreq_policy *policy) {
> >> + int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq,
> >> +ret;
> >> + struct amd_cpudata *cpudata;
> >> + struct device *dev;
> >> + int rc;
> >> + u64 value;
> >> +
> >> + rc = amd_pstate_init_cpu(policy->cpu);
> >> + if (rc)
> >> + return rc;
> >> +
> >> + cpudata = all_cpu_data[policy->cpu];
> >> +
> >> + dev = get_cpu_device(policy->cpu);
> >> + if (!dev)
> >> + goto free_cpudata1;
> >> +
> >> + rc = amd_pstate_init_perf(cpudata);
> >> + if (rc)
> >> + goto free_cpudata1;
> >> +
> >> + min_freq = amd_get_min_freq(cpudata);
> >> + max_freq = amd_get_max_freq(cpudata);
> >> + nominal_freq = amd_get_nominal_freq(cpudata);
> >> + lowest_nonlinear_freq = amd_get_lowest_nonlinear_freq(cpudata);
> >> + if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
> >> + dev_err(dev, "min_freq(%d) or max_freq(%d) value is
> >> +incorrect\n",
> >> + min_freq, max_freq);
> >> + ret = -EINVAL;
> >> + goto free_cpudata1;
> >> + }
> >> +
> >> + policy->min = min_freq;
> >> + policy->max = max_freq;
> >> +
> >> + policy->cpuinfo.min_freq = min_freq;
> >> + policy->cpuinfo.max_freq = max_freq;
> >> + /* It will be updated by governor */
> >> + policy->cur = policy->cpuinfo.min_freq;
> >> +
> >> + /* Initial processor data capability frequencies */
> >> + cpudata->max_freq = max_freq;
> >> + cpudata->min_freq = min_freq;
> >> + cpudata->nominal_freq = nominal_freq;
> >> + cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
> >> +
> >> + policy->driver_data = cpudata;
> >> +
> >> + update_boost_state();
> >> + cpudata->epp_cached = amd_pstate_get_epp(cpudata, value);
> >> +
> >> + policy->min = policy->cpuinfo.min_freq;
> >> + policy->max = policy->cpuinfo.max_freq;
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC))
> >> + policy->fast_switch_possible = true;
> >> +
> >> + if (!shared_mem && boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value);
> >> + if (ret)
> >> + return ret;
> >> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> >> +
> >> + ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
> >> +&value);
> >> + if (ret)
> >> + return ret;
> >> + WRITE_ONCE(cpudata->cppc_cap1_cached, value);
> >> + }
> >> + amd_pstate_boost_init(cpudata);
> >> +
> >> + return 0;
> >> +
> >> +free_cpudata1:
> >> + kfree(cpudata);
> >> + return ret;
> >> +}
> >> +
> >> +static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) {
> >> + int ret;
> >> +
> >> + ret = __amd_pstate_cpu_init(policy);
> >> + if (ret)
> >> + return ret;
> >> + /*
> >> + * Set the policy to powersave to provide a valid fallback value
> >> +in case
> >> + * the default cpufreq governor is neither powersave nor performance.
> >> + */
> >> + policy->policy = CPUFREQ_POLICY_POWERSAVE;
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy) {
> >> + pr_debug("amd-pstate: CPU %d exiting\n", policy->cpu);
> >
> > Drop the "amd-pstate:", this file has pr_fmt.
> >
> >> + policy->fast_switch_possible = false;
> >> + return 0;
> >> +}
> >> +
> >> +static void amd_pstate_update_max_freq(unsigned int cpu) {
> >> + struct cpufreq_policy *policy = policy = cpufreq_cpu_get(cpu);
> >> +
> >> + if (!policy)
> >> + return;
> >> +
> >> + refresh_frequency_limits(policy);
> >> + cpufreq_cpu_put(policy);
> >> +}
> >> +
> >> +static void amd_pstate_epp_update_limits(unsigned int cpu) {
> >> + mutex_lock(&amd_pstate_driver_lock);
> >> + update_boost_state();
> >> + if (global_params.cppc_boost_disabled) {
> >> + for_each_possible_cpu(cpu)
> >> + amd_pstate_update_max_freq(cpu);
> >> + } else {
> >> + cpufreq_update_policy(cpu);
> >> + }
> >> + mutex_unlock(&amd_pstate_driver_lock);
> >> +}
> >> +
> >> +static int cppc_boost_hold_time_ns = 3 * NSEC_PER_MSEC;
> >> +
> >> +static inline void amd_pstate_boost_up(struct amd_cpudata *cpudata)
> >> +{
> >> + u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
> >> + u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
> >> + u32 max_limit = (hwp_req & 0xff);
> >> + u32 min_limit = (hwp_req & 0xff00) >> 8;
> >> + u32 boost_level1;
> >> +
> >> + /* If max and min are equal or already at max, nothing to boost
> >> +*/
> >> + if (max_limit == min_limit)
> >> + return;
> >> +
> >> + /* Set boost max and min to initial value */
> >> + if (!cpudata->cppc_boost_min)
> >> + cpudata->cppc_boost_min = min_limit;
> >> +
> >> + boost_level1 = ((AMD_CPPC_NOMINAL_PERF(hwp_cap) +
> min_limit) >>
> >> +1);
> >> +
> >> + if (cpudata->cppc_boost_min < boost_level1)
> >> + cpudata->cppc_boost_min = boost_level1;
> >> + else if (cpudata->cppc_boost_min <
> >> +AMD_CPPC_NOMINAL_PERF(hwp_cap))
> >> + cpudata->cppc_boost_min =
> AMD_CPPC_NOMINAL_PERF(hwp_cap);
> >> + else if (cpudata->cppc_boost_min ==
> >> +AMD_CPPC_NOMINAL_PERF(hwp_cap))
> >> + cpudata->cppc_boost_min = max_limit;
> >> + else
> >> + return;
> >> +
> >> + hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
> >> + hwp_req |= AMD_CPPC_MIN_PERF(cpudata->cppc_boost_min);
> >> + wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
> hwp_req);
> >> + cpudata->last_update = cpudata->sample.time; }
> >> +
> >> +static inline void amd_pstate_boost_down(struct amd_cpudata
> >> +*cpudata) {
> >> + bool expired;
> >> +
> >> + if (cpudata->cppc_boost_min) {
> >> + expired = time_after64(cpudata->sample.time,
> >> +cpudata->last_update +
> >> + cppc_boost_hold_time_ns);
> >> +
> >> + if (expired) {
> >> + wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
> >> + cpudata->cppc_req_cached);
> >> + cpudata->cppc_boost_min = 0;
> >> + }
> >> + }
> >> +
> >> + cpudata->last_update = cpudata->sample.time; }
> >> +
> >> +static inline void amd_pstate_boost_update_util(struct amd_cpudata
> >> +*cpudata,
> >> + u64 time) {
> >> + cpudata->sample.time = time;
> >> + if (smp_processor_id() != cpudata->cpu)
> >> + return;
> >> +
> >> + if (cpudata->sched_flags & SCHED_CPUFREQ_IOWAIT) {
> >> + bool do_io = false;
> >> +
> >> + cpudata->sched_flags = 0;
> >> + /*
> >> + * Set iowait_boost flag and update time. Since IO WAIT flag
> >> + * is set all the time, we can't just conclude that there is
> >> + * some IO bound activity is scheduled on this CPU with just
> >> + * one occurrence. If we receive at least two in two
> >> + * consecutive ticks, then we treat as boost candidate.
> >> + * This is leveraged from Intel Pstate driver.
> >> + */
> >> + if (time_before64(time, cpudata->last_io_update + 2 *
> >> +TICK_NSEC))
> >> + do_io = true;
> >> +
> >> + cpudata->last_io_update = time;
> >> +
> >> + if (do_io)
> >> + amd_pstate_boost_up(cpudata);
> >> +
> >> + } else {
> >> + amd_pstate_boost_down(cpudata);
> >> + }
> >> +}
> >> +
> >> +static inline void amd_pstate_cppc_update_hook(struct
> >> +update_util_data *data,
> >> + u64 time, unsigned int flags) {
> >> + struct amd_cpudata *cpudata = container_of(data,
> >> + struct amd_cpudata, update_util);
> >> +
> >> + cpudata->sched_flags |= flags;
> >> +
> >> + if (smp_processor_id() == cpudata->cpu)
> >> + amd_pstate_boost_update_util(cpudata, time); }
> >> +
> >> +static void amd_pstate_clear_update_util_hook(unsigned int cpu) {
> >> + struct amd_cpudata *cpudata = all_cpu_data[cpu];
> >> +
> >> + if (!cpudata->update_util_set)
> >> + return;
> >> +
> >> + cpufreq_remove_update_util_hook(cpu);
> >> + cpudata->update_util_set = false;
> >> + synchronize_rcu();
> >> +}
> >> +
> >> +static void amd_pstate_set_update_util_hook(unsigned int cpu_num) {
> >> + struct amd_cpudata *cpudata = all_cpu_data[cpu_num];
> >> +
> >> + if (!cppc_boost) {
> >> + if (cpudata->update_util_set)
> >> + amd_pstate_clear_update_util_hook(cpudata->cpu);
> >> + return;
> >> + }
> >> +
> >> + if (cpudata->update_util_set)
> >> + return;
> >> +
> >> + cpudata->sample.time = 0;
> >> + cpufreq_add_update_util_hook(cpu_num, &cpudata->update_util,
> >> + amd_pstate_cppc_update_hook);
> >> + cpudata->update_util_set = true; }
> >> +
> >> +static void amd_pstate_epp_init(unsigned int cpu) {
> >> + struct amd_cpudata *cpudata = all_cpu_data[cpu];
> >> + u32 max_perf, min_perf;
> >> + u64 value;
> >> + s16 epp;
> >> + int ret;
> >> +
> >> + max_perf = READ_ONCE(cpudata->highest_perf);
> >> + min_perf = READ_ONCE(cpudata->lowest_perf);
> >> +
> >> + value = READ_ONCE(cpudata->cppc_req_cached);
> >> +
> >> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
> >> + min_perf = max_perf;
> >> +
> >> + /* Initial min/max values for CPPC Performance Controls Register
> >> +*/
> >> + value &= ~AMD_CPPC_MIN_PERF(~0L);
> >> + value |= AMD_CPPC_MIN_PERF(min_perf);
> >> +
> >> + value &= ~AMD_CPPC_MAX_PERF(~0L);
> >> + value |= AMD_CPPC_MAX_PERF(max_perf);
> >> +
> >> + /* CPPC EPP feature require to set zero to the desire perf bit
> >> +*/
> >> + value &= ~AMD_CPPC_DES_PERF(~0L);
> >> + value |= AMD_CPPC_DES_PERF(0);
> >> +
> >> + if (cpudata->epp_policy == cpudata->policy)
> >> + goto skip_epp;
> >> +
> >> + cpudata->epp_policy = cpudata->policy;
> >> +
> >> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
> >> + epp = amd_pstate_get_epp(cpudata, value);
> >> + cpudata->epp_powersave = epp;
> >> + if (epp < 0)
> >> + goto skip_epp;
> >> + /* force the epp value to be zero for performance policy */
> >> + epp = 0;
> >> + } else {
> >> + if (cpudata->epp_powersave < 0)
> >> + goto skip_epp;
> >> + /* Get BIOS pre-defined epp value */
> >> + epp = amd_pstate_get_epp(cpudata, value);
> >> + if (epp)
> >> + goto skip_epp;
> >> + epp = cpudata->epp_powersave;
> >> + }
> >> + /* Set initial EPP value */
> >> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + value &= ~GENMASK_ULL(31, 24);
> >> + value |= (u64)epp << 24;
> >> + }
> >> +
> >> +skip_epp:
> >> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> >> + ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> >> + if (!ret)
> >> + cpudata->epp_cached = epp;
> >> +}
> >> +
> >> +static void amd_pstate_set_max_limits(struct amd_cpudata *cpudata) {
> >> + u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
> >> + u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
> >> + u32 max_limit = (hwp_cap >> 24) & 0xff;
> >> +
> >> + hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
> >> + hwp_req |= AMD_CPPC_MIN_PERF(max_limit);
> >> + wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, hwp_req); }
> >> +
> >> +static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
> >> +{
> >> + struct amd_cpudata *cpudata;
> >> +
> >> + if (!policy->cpuinfo.max_freq)
> >> + return -ENODEV;
> >> +
> >> + pr_debug("set_policy: cpuinfo.max %u policy->max %u\n",
> >> + policy->cpuinfo.max_freq, policy->max);
> >> +
> >> + cpudata = all_cpu_data[policy->cpu];
> >> + cpudata->policy = policy->policy;
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + mutex_lock(&amd_pstate_limits_lock);
> >> +
> >> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
> >> + amd_pstate_clear_update_util_hook(policy->cpu);
> >> + amd_pstate_set_max_limits(cpudata);
> >> + } else {
> >> + amd_pstate_set_update_util_hook(policy->cpu);
> >> + }
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC))
> >> + amd_pstate_epp_init(policy->cpu);
> >> +
> >> + mutex_unlock(&amd_pstate_limits_lock);
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static void amd_pstate_verify_cpu_policy(struct amd_cpudata
> >> +*cpudata,
> >> + struct cpufreq_policy_data *policy) {
> >> + update_boost_state();
> >> + cpufreq_verify_within_cpu_limits(policy);
> >> +}
> >> +
> >> +static int amd_pstate_epp_verify_policy(struct cpufreq_policy_data
> >> +*policy) {
> >> + amd_pstate_verify_cpu_policy(all_cpu_data[policy->cpu], policy);
> >> + pr_debug("policy_max =%d, policy_min=%d\n", policy->max,
> >> +policy->min);
> >> + return 0;
> >> +}
> >> +
> >> static struct cpufreq_driver amd_pstate_driver = {
> >> .flags = CPUFREQ_CONST_LOOPS |
> >> CPUFREQ_NEED_UPDATE_LIMITS,
> >> .verify = amd_pstate_verify, @@ -607,8 +1222,20 @@
> >> static struct cpufreq_driver amd_pstate_driver = {
> >> .attr = amd_pstate_attr,
> >> };
> >> +static struct cpufreq_driver amd_pstate_epp_driver = {
> >> + .flags = CPUFREQ_CONST_LOOPS,
> >> + .verify = amd_pstate_epp_verify_policy,
> >> + .setpolicy = amd_pstate_epp_set_policy,
> >> + .init = amd_pstate_epp_cpu_init,
> >> + .exit = amd_pstate_epp_cpu_exit,
> >> + .update_limits = amd_pstate_epp_update_limits,
> >> + .name = "amd_pstate_epp",
> >> + .attr = amd_pstate_epp_attr, };
> >> +
> >> static int __init amd_pstate_init(void)
> >> {
> >> + static struct amd_cpudata **cpudata;
> >> int ret;
> >> if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) @@ -623,10
> >> +1250,18 @@ static int __init amd_pstate_init(void)
> >> if (cpufreq_get_current_driver())
> >> return -EEXIST;
> >> + if (!epp_off) {
> >> + WRITE_ONCE(cppc_active, 1);
> >> + if (!default_pstate_driver)
> >> + default_pstate_driver = &amd_pstate_epp_driver;
> >> + }
> >> + pr_info("AMD CPPC loading with %s driver instance.\n",
> >> +default_pstate_driver->name);
> >
> > This is pretty noisy, do we really need it on every boot if we can easily
> check it from sysfs?
> >
> >> +
> >> /* capability check */
> >> if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + if (!cppc_active)
> >> + default_pstate_driver->adjust_perf =
> >> +amd_pstate_adjust_perf;
> >> pr_debug("AMD CPPC MSR based functionality is
> >> supported\n");
> >> - amd_pstate_driver.adjust_perf = amd_pstate_adjust_perf;
> >> } else if (shared_mem) {
> >> static_call_update(amd_pstate_enable, cppc_enable);
> >> static_call_update(amd_pstate_init_perf, cppc_init_perf);
> >> @@ -636,6 +1271,10 @@ static int __init amd_pstate_init(void)
> >> return -ENODEV;
> >> }
> >> + cpudata = vzalloc(array_size(sizeof(void *),
> >> num_possible_cpus()));
> >> + if (!cpudata)
> >> + return -ENOMEM;
> >> + WRITE_ONCE(all_cpu_data, cpudata);
> >> /* enable amd pstate feature */
> >> ret = amd_pstate_enable(true);
> >> if (ret) {
> >> @@ -643,9 +1282,9 @@ static int __init amd_pstate_init(void)
> >> return ret;
> >> }
> >> - ret = cpufreq_register_driver(&amd_pstate_driver);
> >> + ret = cpufreq_register_driver(default_pstate_driver);
> >> if (ret)
> >> - pr_err("failed to register amd_pstate_driver with return
> >> %d\n",
> >> + pr_err("failed to register amd pstate driver with return
> >> +%d\n",
> >> ret);
> >> return ret;
> >> @@ -657,6 +1296,15 @@ static int __init amd_pstate_param(char *str)
> >> if (!str)
> >> return -EINVAL;
> >> + if (!strcmp(str, "disable"))
> >> + disable_pstate_load = 1;
> >> + else if (!strcmp(str, "active")) {
> >> + default_pstate_driver = &amd_pstate_epp_driver;
> >> + } else if (!strcmp(str, "passive")) {
> >> + epp_off = 1;
> >> + default_pstate_driver = &amd_pstate_driver;
> >> + }
> >> +
> >> /* enable shared memory type CPPC ,if you processor has no MSR,
> >> you have to add this
> >> * to your grub to make cppc driver loaded successfully.
> >> */
> >> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> >> index 1c4b8659f171..7e6e8cab97b3 100644
> >> --- a/include/linux/amd-pstate.h
> >> +++ b/include/linux/amd-pstate.h
> >> @@ -25,6 +25,7 @@ struct amd_aperf_mperf {
> >> u64 aperf;
> >> u64 mperf;
> >> u64 tsc;
> >> + u64 time;
> >> };
> >> /**
> >> @@ -47,6 +48,18 @@ struct amd_aperf_mperf {
> >> * @prev: Last Aperf/Mperf/tsc count value read from register
> >> * @freq: current cpu frequency value
> >> * @boost_supported: check whether the Processor or SBIOS supports
> >> boost mode
> >> + * @epp_powersave: Last saved CPPC energy performance preference
> >> + when policy switched to performance
> >> + * @epp_policy: Last saved policy used to set energy-performance
> >> +preference
> >> + * @epp_cached: Cached CPPC energy-performance preference value
> >> + * @policy: Cpufreq policy value
> >> + * @sched_flags: Store scheduler flags for possible cross CPU update
> >> + * @update_util_set: CPUFreq utility callback is set
> >> + * @last_update: Time stamp of the last performance state update
> >> + * @cppc_boost_min: Last CPPC boosted min performance state
> >> + * @cppc_cap1_cached: Cached value of the last CPPC Capabilities MSR
> >> + * @update_util: Cpufreq utility callback information
> >> + * @sample: the stored performance sample
> >> *
> >> * The amd_cpudata is key private data for each CPU thread in AMD
> >> P-State, and
> >> * represents all the attributes and goals that AMD P-State requests at
> runtime.
> >> @@ -72,6 +85,74 @@ struct amd_cpudata {
> >> u64 freq;
> >> bool boost_supported;
> >> +
> >> + /* EPP feature related attributes*/
> >> + s16 epp_powersave;
> >> + s16 epp_policy;
> >> + s16 epp_cached;
> >> + u32 policy;
> >> + u32 sched_flags;
> >> + bool update_util_set;
> >> + u64 last_update;
> >> + u64 last_io_update;
> >> + u32 cppc_boost_min;
> >> + u64 cppc_cap1_cached;
> >> + struct update_util_data update_util;
> >> + struct amd_aperf_mperf sample; };
> >> +
> >> +/**
> >> + * struct amd_pstate_params - global parameters for the performance
> >> +control
> >> + * @ cppc_boost_disabled wheher the core performance boost disabled
> >> +*/ struct amd_pstate_params {
> >> + bool cppc_boost_disabled;
> >> +};
> >> +
> >> +#define AMD_CPPC_EPP_PERFORMANCE 0x00 #define
> >> +AMD_CPPC_EPP_BALANCE_PERFORMANCE 0x80 #define
> >> +AMD_CPPC_EPP_BALANCE_POWERSAVE 0xBF #define
> >> +AMD_CPPC_EPP_POWERSAVE 0xFF
> >> +
> >> +/*
> >> + * AMD Energy Preference Performance (EPP)
> >> + * The EPP is used in the CCLK DPM controller to drive
> >> + * the frequency that a core is going to operate during
> >> + * short periods of activity. EPP values will be utilized for
> >> + * different OS profiles (balanced, performance, power savings)
> >> + * display strings corresponding to EPP index in the
> >> + * energy_perf_strings[]
> >> + * index String
> >> + *-------------------------------------
> >> + * 0 default
> >> + * 1 performance
> >> + * 2 balance_performance
> >> + * 3 balance_power
> >> + * 4 power
> >> + */
> >> +enum energy_perf_value_index {
> >> + EPP_INDEX_DEFAULT = 0,
> >> + EPP_INDEX_PERFORMANCE,
> >> + EPP_INDEX_BALANCE_PERFORMANCE,
> >> + EPP_INDEX_BALANCE_POWERSAVE,
> >> + EPP_INDEX_POWERSAVE,
> >> +};
> >> +
> >> +static const char * const energy_perf_strings[] = {
> >> + [EPP_INDEX_DEFAULT] = "default",
> >> + [EPP_INDEX_PERFORMANCE] = "performance",
> >> + [EPP_INDEX_BALANCE_PERFORMANCE] = "balance_performance",
> >> + [EPP_INDEX_BALANCE_POWERSAVE] = "balance_power",
> >> + [EPP_INDEX_POWERSAVE] = "power",
> >> + NULL
> >> +};
> >> +
> >> +static unsigned int epp_values[] = {
> >> + [EPP_INDEX_DEFAULT] = 0,
> >> + [EPP_INDEX_PERFORMANCE] = AMD_CPPC_EPP_PERFORMANCE,
> >> + [EPP_INDEX_BALANCE_PERFORMANCE] =
> >> +AMD_CPPC_EPP_BALANCE_PERFORMANCE,
> >> + [EPP_INDEX_BALANCE_POWERSAVE] =
> AMD_CPPC_EPP_BALANCE_POWERSAVE,
> >> + [EPP_INDEX_POWERSAVE] = AMD_CPPC_EPP_POWERSAVE,
> >> };
> >> #endif /* _LINUX_AMD_PSTATE_H */
> >