diff options
Diffstat (limited to 'drivers/cpufreq/amd-pstate.c')
| -rw-r--r-- | drivers/cpufreq/amd-pstate.c | 720 |
1 files changed, 720 insertions, 0 deletions
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c new file mode 100644 index 000000000..edc294ee5 --- /dev/null +++ b/drivers/cpufreq/amd-pstate.c @@ -0,0 +1,720 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * amd-pstate.c - AMD Processor P-state Frequency Driver + * + * Copyright (C) 2021 Advanced Micro Devices, Inc. All Rights Reserved. + * + * Author: Huang Rui <ray.huang@amd.com> + * + * AMD P-State introduces a new CPU performance scaling design for AMD + * processors using the ACPI Collaborative Performance and Power Control (CPPC) + * feature which works with the AMD SMU firmware providing a finer grained + * frequency control range. It is to replace the legacy ACPI P-States control, + * allows a flexible, low-latency interface for the Linux kernel to directly + * communicate the performance hints to hardware. + * + * AMD P-State is supported on recent AMD Zen base CPU series include some of + * Zen2 and Zen3 processors. _CPC needs to be present in the ACPI tables of AMD + * P-State supported system. And there are two types of hardware implementations + * for AMD P-State: 1) Full MSR Solution and 2) Shared Memory Solution. + * X86_FEATURE_CPPC CPU feature flag is used to distinguish the different types. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/smp.h> +#include <linux/sched.h> +#include <linux/cpufreq.h> +#include <linux/compiler.h> +#include <linux/dmi.h> +#include <linux/slab.h> +#include <linux/acpi.h> +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/uaccess.h> +#include <linux/static_call.h> +#include <linux/amd-pstate.h> + +#include <acpi/processor.h> +#include <acpi/cppc_acpi.h> + +#include <asm/msr.h> +#include <asm/processor.h> +#include <asm/cpufeature.h> +#include <asm/cpu_device_id.h> +#include "amd-pstate-trace.h" + +#define AMD_PSTATE_TRANSITION_LATENCY 20000 +#define AMD_PSTATE_TRANSITION_DELAY 1000 + +/* + * TODO: We need more time to fine tune processors with shared memory solution + * with community together. + * + * There are some performance drops on the CPU benchmarks which reports from + * Suse. We are co-working with them to fine tune the shared memory solution. So + * we disable it by default to go acpi-cpufreq on these processors and add a + * module parameter to be able to enable it manually for debugging. + */ +static struct cpufreq_driver amd_pstate_driver; +static int cppc_load __initdata; + +static inline int pstate_enable(bool enable) +{ + return wrmsrl_safe(MSR_AMD_CPPC_ENABLE, enable); +} + +static int cppc_enable(bool enable) +{ + int cpu, ret = 0; + + for_each_present_cpu(cpu) { + ret = cppc_set_enable(cpu, enable); + if (ret) + return ret; + } + + return ret; +} + +DEFINE_STATIC_CALL(amd_pstate_enable, pstate_enable); + +static inline int amd_pstate_enable(bool enable) +{ + return static_call(amd_pstate_enable)(enable); +} + +static int pstate_init_perf(struct amd_cpudata *cpudata) +{ + u64 cap1; + u32 highest_perf; + + int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1, + &cap1); + if (ret) + return ret; + + /* + * TODO: Introduce AMD specific power feature. + * + * CPPC entry doesn't indicate the highest performance in some ASICs. + */ + highest_perf = amd_get_highest_perf(); + if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1)) + highest_perf = AMD_CPPC_HIGHEST_PERF(cap1); + + WRITE_ONCE(cpudata->highest_perf, highest_perf); + + WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1)); + WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1)); + WRITE_ONCE(cpudata->lowest_perf, AMD_CPPC_LOWEST_PERF(cap1)); + + return 0; +} + +static int cppc_init_perf(struct amd_cpudata *cpudata) +{ + struct cppc_perf_caps cppc_perf; + u32 highest_perf; + + int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); + if (ret) + return ret; + + highest_perf = amd_get_highest_perf(); + if (highest_perf > cppc_perf.highest_perf) + highest_perf = cppc_perf.highest_perf; + + WRITE_ONCE(cpudata->highest_perf, highest_perf); + + WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf); + WRITE_ONCE(cpudata->lowest_nonlinear_perf, + cppc_perf.lowest_nonlinear_perf); + WRITE_ONCE(cpudata->lowest_perf, cppc_perf.lowest_perf); + + return 0; +} + +DEFINE_STATIC_CALL(amd_pstate_init_perf, pstate_init_perf); + +static inline int amd_pstate_init_perf(struct amd_cpudata *cpudata) +{ + return static_call(amd_pstate_init_perf)(cpudata); +} + +static void pstate_update_perf(struct amd_cpudata *cpudata, u32 min_perf, + u32 des_perf, u32 max_perf, bool fast_switch) +{ + if (fast_switch) + wrmsrl(MSR_AMD_CPPC_REQ, READ_ONCE(cpudata->cppc_req_cached)); + else + wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, + READ_ONCE(cpudata->cppc_req_cached)); +} + +static void cppc_update_perf(struct amd_cpudata *cpudata, + u32 min_perf, u32 des_perf, + u32 max_perf, bool fast_switch) +{ + struct cppc_perf_ctrls perf_ctrls; + + perf_ctrls.max_perf = max_perf; + perf_ctrls.min_perf = min_perf; + perf_ctrls.desired_perf = des_perf; + + cppc_set_perf(cpudata->cpu, &perf_ctrls); +} + +DEFINE_STATIC_CALL(amd_pstate_update_perf, pstate_update_perf); + +static inline void amd_pstate_update_perf(struct amd_cpudata *cpudata, + u32 min_perf, u32 des_perf, + u32 max_perf, bool fast_switch) +{ + static_call(amd_pstate_update_perf)(cpudata, min_perf, des_perf, + max_perf, fast_switch); +} + +static inline bool amd_pstate_sample(struct amd_cpudata *cpudata) +{ + u64 aperf, mperf, tsc; + unsigned long flags; + + local_irq_save(flags); + rdmsrl(MSR_IA32_APERF, aperf); + rdmsrl(MSR_IA32_MPERF, mperf); + tsc = rdtsc(); + + if (cpudata->prev.mperf == mperf || cpudata->prev.tsc == tsc) { + local_irq_restore(flags); + return false; + } + + local_irq_restore(flags); + + cpudata->cur.aperf = aperf; + cpudata->cur.mperf = mperf; + cpudata->cur.tsc = tsc; + cpudata->cur.aperf -= cpudata->prev.aperf; + cpudata->cur.mperf -= cpudata->prev.mperf; + cpudata->cur.tsc -= cpudata->prev.tsc; + + cpudata->prev.aperf = aperf; + cpudata->prev.mperf = mperf; + cpudata->prev.tsc = tsc; + + cpudata->freq = div64_u64((cpudata->cur.aperf * cpu_khz), cpudata->cur.mperf); + + return true; +} + +static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf, + u32 des_perf, u32 max_perf, bool fast_switch) +{ + u64 prev = READ_ONCE(cpudata->cppc_req_cached); + u64 value = prev; + + des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf); + value &= ~AMD_CPPC_MIN_PERF(~0L); + value |= AMD_CPPC_MIN_PERF(min_perf); + + value &= ~AMD_CPPC_DES_PERF(~0L); + value |= AMD_CPPC_DES_PERF(des_perf); + + value &= ~AMD_CPPC_MAX_PERF(~0L); + value |= AMD_CPPC_MAX_PERF(max_perf); + + if (trace_amd_pstate_perf_enabled() && amd_pstate_sample(cpudata)) { + trace_amd_pstate_perf(min_perf, des_perf, max_perf, cpudata->freq, + cpudata->cur.mperf, cpudata->cur.aperf, cpudata->cur.tsc, + cpudata->cpu, (value != prev), fast_switch); + } + + if (value == prev) + return; + + WRITE_ONCE(cpudata->cppc_req_cached, value); + + amd_pstate_update_perf(cpudata, min_perf, des_perf, + max_perf, fast_switch); +} + +static int amd_pstate_verify(struct cpufreq_policy_data *policy) +{ + cpufreq_verify_within_cpu_limits(policy); + + return 0; +} + +static int amd_pstate_update_freq(struct cpufreq_policy *policy, + unsigned int target_freq, bool fast_switch) +{ + struct cpufreq_freqs freqs; + struct amd_cpudata *cpudata = policy->driver_data; + unsigned long max_perf, min_perf, des_perf, cap_perf; + + if (!cpudata->max_freq) + return -ENODEV; + + cap_perf = READ_ONCE(cpudata->highest_perf); + min_perf = READ_ONCE(cpudata->lowest_perf); + max_perf = cap_perf; + + freqs.old = policy->cur; + freqs.new = target_freq; + + des_perf = DIV_ROUND_CLOSEST(target_freq * cap_perf, + cpudata->max_freq); + + WARN_ON(fast_switch && !policy->fast_switch_enabled); + /* + * If fast_switch is desired, then there aren't any registered + * transition notifiers. See comment for + * cpufreq_enable_fast_switch(). + */ + if (!fast_switch) + cpufreq_freq_transition_begin(policy, &freqs); + + amd_pstate_update(cpudata, min_perf, des_perf, max_perf, fast_switch); + + if (!fast_switch) + cpufreq_freq_transition_end(policy, &freqs, false); + + return 0; +} + +static int amd_pstate_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + return amd_pstate_update_freq(policy, target_freq, false); +} + +static unsigned int amd_pstate_fast_switch(struct cpufreq_policy *policy, + unsigned int target_freq) +{ + if (!amd_pstate_update_freq(policy, target_freq, true)) + return target_freq; + return policy->cur; +} + +static void amd_pstate_adjust_perf(unsigned int cpu, + unsigned long _min_perf, + unsigned long target_perf, + unsigned long capacity) +{ + unsigned long max_perf, min_perf, des_perf, + cap_perf, lowest_nonlinear_perf, max_freq; + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + struct amd_cpudata *cpudata = policy->driver_data; + unsigned int target_freq; + + cap_perf = READ_ONCE(cpudata->highest_perf); + lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf); + max_freq = READ_ONCE(cpudata->max_freq); + + des_perf = cap_perf; + if (target_perf < capacity) + des_perf = DIV_ROUND_UP(cap_perf * target_perf, capacity); + + min_perf = READ_ONCE(cpudata->highest_perf); + if (_min_perf < capacity) + min_perf = DIV_ROUND_UP(cap_perf * _min_perf, capacity); + + if (min_perf < lowest_nonlinear_perf) + min_perf = lowest_nonlinear_perf; + + max_perf = cap_perf; + if (max_perf < min_perf) + max_perf = min_perf; + + des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf); + target_freq = div_u64(des_perf * max_freq, max_perf); + policy->cur = target_freq; + + amd_pstate_update(cpudata, min_perf, des_perf, max_perf, true); + cpufreq_cpu_put(policy); +} + +static int amd_get_min_freq(struct amd_cpudata *cpudata) +{ + struct cppc_perf_caps cppc_perf; + + int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); + if (ret) + return ret; + + /* Switch to khz */ + return cppc_perf.lowest_freq * 1000; +} + +static int amd_get_max_freq(struct amd_cpudata *cpudata) +{ + struct cppc_perf_caps cppc_perf; + u32 max_perf, max_freq, nominal_freq, nominal_perf; + u64 boost_ratio; + + int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); + if (ret) + return ret; + + nominal_freq = cppc_perf.nominal_freq; + nominal_perf = READ_ONCE(cpudata->nominal_perf); + max_perf = READ_ONCE(cpudata->highest_perf); + + boost_ratio = div_u64(max_perf << SCHED_CAPACITY_SHIFT, + nominal_perf); + + max_freq = nominal_freq * boost_ratio >> SCHED_CAPACITY_SHIFT; + + /* Switch to khz */ + return max_freq * 1000; +} + +static int amd_get_nominal_freq(struct amd_cpudata *cpudata) +{ + struct cppc_perf_caps cppc_perf; + + int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); + if (ret) + return ret; + + /* Switch to khz */ + return cppc_perf.nominal_freq * 1000; +} + +static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata) +{ + struct cppc_perf_caps cppc_perf; + u32 lowest_nonlinear_freq, lowest_nonlinear_perf, + nominal_freq, nominal_perf; + u64 lowest_nonlinear_ratio; + + int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); + if (ret) + return ret; + + nominal_freq = cppc_perf.nominal_freq; + nominal_perf = READ_ONCE(cpudata->nominal_perf); + + lowest_nonlinear_perf = cppc_perf.lowest_nonlinear_perf; + + lowest_nonlinear_ratio = div_u64(lowest_nonlinear_perf << SCHED_CAPACITY_SHIFT, + nominal_perf); + + lowest_nonlinear_freq = nominal_freq * lowest_nonlinear_ratio >> SCHED_CAPACITY_SHIFT; + + /* Switch to khz */ + return lowest_nonlinear_freq * 1000; +} + +static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state) +{ + struct amd_cpudata *cpudata = policy->driver_data; + int ret; + + if (!cpudata->boost_supported) { + pr_err("Boost mode is not supported by this processor or SBIOS\n"); + return -EINVAL; + } + + if (state) + policy->cpuinfo.max_freq = cpudata->max_freq; + else + policy->cpuinfo.max_freq = cpudata->nominal_freq; + + policy->max = policy->cpuinfo.max_freq; + + ret = freq_qos_update_request(&cpudata->req[1], + policy->cpuinfo.max_freq); + if (ret < 0) + return ret; + + return 0; +} + +static void amd_pstate_boost_init(struct amd_cpudata *cpudata) +{ + u32 highest_perf, nominal_perf; + + highest_perf = READ_ONCE(cpudata->highest_perf); + nominal_perf = READ_ONCE(cpudata->nominal_perf); + + if (highest_perf <= nominal_perf) + return; + + cpudata->boost_supported = true; + amd_pstate_driver.boost_enabled = true; +} + +static void amd_perf_ctl_reset(unsigned int cpu) +{ + wrmsrl_on_cpu(cpu, MSR_AMD_PERF_CTL, 0); +} + +static int amd_pstate_cpu_init(struct cpufreq_policy *policy) +{ + int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret; + struct device *dev; + struct amd_cpudata *cpudata; + + /* + * Resetting PERF_CTL_MSR will put the CPU in P0 frequency, + * which is ideal for initialization process. + */ + amd_perf_ctl_reset(policy->cpu); + dev = get_cpu_device(policy->cpu); + if (!dev) + return -ENODEV; + + cpudata = kzalloc(sizeof(*cpudata), GFP_KERNEL); + if (!cpudata) + return -ENOMEM; + + cpudata->cpu = policy->cpu; + + ret = amd_pstate_init_perf(cpudata); + if (ret) + 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->cpuinfo.transition_latency = AMD_PSTATE_TRANSITION_LATENCY; + policy->transition_delay_us = AMD_PSTATE_TRANSITION_DELAY; + + 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; + + if (boot_cpu_has(X86_FEATURE_CPPC)) + policy->fast_switch_possible = true; + + ret = freq_qos_add_request(&policy->constraints, &cpudata->req[0], + FREQ_QOS_MIN, policy->cpuinfo.min_freq); + if (ret < 0) { + dev_err(dev, "Failed to add min-freq constraint (%d)\n", ret); + goto free_cpudata1; + } + + ret = freq_qos_add_request(&policy->constraints, &cpudata->req[1], + FREQ_QOS_MAX, policy->cpuinfo.max_freq); + if (ret < 0) { + dev_err(dev, "Failed to add max-freq constraint (%d)\n", ret); + goto free_cpudata2; + } + + /* 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; + + amd_pstate_boost_init(cpudata); + + return 0; + +free_cpudata2: + freq_qos_remove_request(&cpudata->req[0]); +free_cpudata1: + kfree(cpudata); + return ret; +} + +static int amd_pstate_cpu_exit(struct cpufreq_policy *policy) +{ + struct amd_cpudata *cpudata = policy->driver_data; + + freq_qos_remove_request(&cpudata->req[1]); + freq_qos_remove_request(&cpudata->req[0]); + policy->fast_switch_possible = false; + kfree(cpudata); + + return 0; +} + +static int amd_pstate_cpu_resume(struct cpufreq_policy *policy) +{ + int ret; + + ret = amd_pstate_enable(true); + if (ret) + pr_err("failed to enable amd-pstate during resume, return %d\n", ret); + + return ret; +} + +static int amd_pstate_cpu_suspend(struct cpufreq_policy *policy) +{ + int ret; + + ret = amd_pstate_enable(false); + if (ret) + pr_err("failed to disable amd-pstate during suspend, return %d\n", ret); + + return ret; +} + +/* Sysfs attributes */ + +/* + * This frequency is to indicate the maximum hardware frequency. + * If boost is not active but supported, the frequency will be larger than the + * one in cpuinfo. + */ +static ssize_t show_amd_pstate_max_freq(struct cpufreq_policy *policy, + char *buf) +{ + int max_freq; + struct amd_cpudata *cpudata = policy->driver_data; + + max_freq = amd_get_max_freq(cpudata); + if (max_freq < 0) + return max_freq; + + return sprintf(&buf[0], "%u\n", max_freq); +} + +static ssize_t show_amd_pstate_lowest_nonlinear_freq(struct cpufreq_policy *policy, + char *buf) +{ + int freq; + struct amd_cpudata *cpudata = policy->driver_data; + + freq = amd_get_lowest_nonlinear_freq(cpudata); + if (freq < 0) + return freq; + + return sprintf(&buf[0], "%u\n", freq); +} + +/* + * In some of ASICs, the highest_perf is not the one in the _CPC table, so we + * need to expose it to sysfs. + */ +static ssize_t show_amd_pstate_highest_perf(struct cpufreq_policy *policy, + char *buf) +{ + u32 perf; + struct amd_cpudata *cpudata = policy->driver_data; + + perf = READ_ONCE(cpudata->highest_perf); + + return sprintf(&buf[0], "%u\n", perf); +} + +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); + +static struct freq_attr *amd_pstate_attr[] = { + &amd_pstate_max_freq, + &amd_pstate_lowest_nonlinear_freq, + &amd_pstate_highest_perf, + NULL, +}; + +static struct cpufreq_driver amd_pstate_driver = { + .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS, + .verify = amd_pstate_verify, + .target = amd_pstate_target, + .fast_switch = amd_pstate_fast_switch, + .init = amd_pstate_cpu_init, + .exit = amd_pstate_cpu_exit, + .suspend = amd_pstate_cpu_suspend, + .resume = amd_pstate_cpu_resume, + .set_boost = amd_pstate_set_boost, + .name = "amd-pstate", + .attr = amd_pstate_attr, +}; + +static int __init amd_pstate_init(void) +{ + int ret; + + if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) + return -ENODEV; + /* + * by default the pstate driver is disabled to load + * enable the amd_pstate passive mode driver explicitly + * with amd_pstate=passive in kernel command line + */ + if (!cppc_load) { + pr_debug("driver load is disabled, boot with amd_pstate=passive to enable this\n"); + return -ENODEV; + } + + if (!acpi_cpc_valid()) { + pr_warn_once("the _CPC object is not present in SBIOS or ACPI disabled\n"); + return -ENODEV; + } + + /* don't keep reloading if cpufreq_driver exists */ + if (cpufreq_get_current_driver()) + return -EEXIST; + + /* capability check */ + if (boot_cpu_has(X86_FEATURE_CPPC)) { + pr_debug("AMD CPPC MSR based functionality is supported\n"); + amd_pstate_driver.adjust_perf = amd_pstate_adjust_perf; + } else { + pr_debug("AMD CPPC shared memory based functionality is supported\n"); + static_call_update(amd_pstate_enable, cppc_enable); + static_call_update(amd_pstate_init_perf, cppc_init_perf); + static_call_update(amd_pstate_update_perf, cppc_update_perf); + } + + /* enable amd pstate feature */ + ret = amd_pstate_enable(true); + if (ret) { + pr_err("failed to enable amd-pstate with return %d\n", ret); + return ret; + } + + ret = cpufreq_register_driver(&amd_pstate_driver); + if (ret) + pr_err("failed to register amd_pstate_driver with return %d\n", + ret); + + return ret; +} +device_initcall(amd_pstate_init); + +static int __init amd_pstate_param(char *str) +{ + if (!str) + return -EINVAL; + + if (!strcmp(str, "disable")) { + cppc_load = 0; + pr_info("driver is explicitly disabled\n"); + } else if (!strcmp(str, "passive")) + cppc_load = 1; + + return 0; +} +early_param("amd_pstate", amd_pstate_param); + +MODULE_AUTHOR("Huang Rui <ray.huang@amd.com>"); +MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver"); +MODULE_LICENSE("GPL"); |