linuxdebug/drivers/cpufreq/amd-pstate.c

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2024-07-16 15:50:57 +02:00
// 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)
{
return amd_pstate_update_freq(policy, target_freq, true);
}
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");