blob: 39ac78c94be0f3c191aaf5868cd3c2154ab5fb59 [file] [log] [blame]
/*
* POWERNV cpufreq driver for the IBM POWER processors
*
* (C) Copyright IBM 2014
*
* Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#define pr_fmt(fmt) "powernv-cpufreq: " fmt
#include <linux/kernel.h>
#include <linux/sysfs.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/cpufreq.h>
#include <linux/smp.h>
#include <linux/of.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <trace/events/power.h>
#include <asm/cputhreads.h>
#include <asm/firmware.h>
#include <asm/reg.h>
#include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
#include <asm/opal.h>
#define POWERNV_MAX_PSTATES 256
#define PMSR_PSAFE_ENABLE (1UL << 30)
#define PMSR_SPR_EM_DISABLE (1UL << 31)
#define PMSR_MAX(x) ((x >> 32) & 0xFF)
static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
static bool rebooting, throttled, occ_reset;
static const char * const throttle_reason[] = {
"No throttling",
"Power Cap",
"Processor Over Temperature",
"Power Supply Failure",
"Over Current",
"OCC Reset"
};
enum throttle_reason_type {
NO_THROTTLE = 0,
POWERCAP,
CPU_OVERTEMP,
POWER_SUPPLY_FAILURE,
OVERCURRENT,
OCC_RESET_THROTTLE,
OCC_MAX_REASON
};
static struct chip {
unsigned int id;
bool throttled;
bool restore;
u8 throttle_reason;
cpumask_t mask;
struct work_struct throttle;
int throttle_turbo;
int throttle_sub_turbo;
int reason[OCC_MAX_REASON];
} *chips;
static int nr_chips;
static DEFINE_PER_CPU(struct chip *, chip_info);
/*
* Note: The set of pstates consists of contiguous integers, the
* smallest of which is indicated by powernv_pstate_info.min, the
* largest of which is indicated by powernv_pstate_info.max.
*
* The nominal pstate is the highest non-turbo pstate in this
* platform. This is indicated by powernv_pstate_info.nominal.
*/
static struct powernv_pstate_info {
int min;
int max;
int nominal;
int nr_pstates;
} powernv_pstate_info;
/*
* Initialize the freq table based on data obtained
* from the firmware passed via device-tree
*/
static int init_powernv_pstates(void)
{
struct device_node *power_mgt;
int i, pstate_min, pstate_max, pstate_nominal, nr_pstates = 0;
const __be32 *pstate_ids, *pstate_freqs;
u32 len_ids, len_freqs;
power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
if (!power_mgt) {
pr_warn("power-mgt node not found\n");
return -ENODEV;
}
if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
pr_warn("ibm,pstate-min node not found\n");
return -ENODEV;
}
if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
pr_warn("ibm,pstate-max node not found\n");
return -ENODEV;
}
if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
&pstate_nominal)) {
pr_warn("ibm,pstate-nominal not found\n");
return -ENODEV;
}
pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min,
pstate_nominal, pstate_max);
pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
if (!pstate_ids) {
pr_warn("ibm,pstate-ids not found\n");
return -ENODEV;
}
pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
&len_freqs);
if (!pstate_freqs) {
pr_warn("ibm,pstate-frequencies-mhz not found\n");
return -ENODEV;
}
if (len_ids != len_freqs) {
pr_warn("Entries in ibm,pstate-ids and "
"ibm,pstate-frequencies-mhz does not match\n");
}
nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
if (!nr_pstates) {
pr_warn("No PStates found\n");
return -ENODEV;
}
pr_debug("NR PStates %d\n", nr_pstates);
for (i = 0; i < nr_pstates; i++) {
u32 id = be32_to_cpu(pstate_ids[i]);
u32 freq = be32_to_cpu(pstate_freqs[i]);
pr_debug("PState id %d freq %d MHz\n", id, freq);
powernv_freqs[i].frequency = freq * 1000; /* kHz */
powernv_freqs[i].driver_data = id;
}
/* End of list marker entry */
powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
powernv_pstate_info.min = pstate_min;
powernv_pstate_info.max = pstate_max;
powernv_pstate_info.nominal = pstate_nominal;
powernv_pstate_info.nr_pstates = nr_pstates;
return 0;
}
/* Returns the CPU frequency corresponding to the pstate_id. */
static unsigned int pstate_id_to_freq(int pstate_id)
{
int i;
i = powernv_pstate_info.max - pstate_id;
if (i >= powernv_pstate_info.nr_pstates || i < 0) {
pr_warn("PState id %d outside of PState table, "
"reporting nominal id %d instead\n",
pstate_id, powernv_pstate_info.nominal);
i = powernv_pstate_info.max - powernv_pstate_info.nominal;
}
return powernv_freqs[i].frequency;
}
/*
* cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
* the firmware
*/
static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
char *buf)
{
return sprintf(buf, "%u\n",
pstate_id_to_freq(powernv_pstate_info.nominal));
}
struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
__ATTR_RO(cpuinfo_nominal_freq);
static struct freq_attr *powernv_cpu_freq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
&cpufreq_freq_attr_cpuinfo_nominal_freq,
NULL,
};
#define throttle_attr(name, member) \
static ssize_t name##_show(struct cpufreq_policy *policy, char *buf) \
{ \
struct chip *chip = per_cpu(chip_info, policy->cpu); \
\
return sprintf(buf, "%u\n", chip->member); \
} \
\
static struct freq_attr throttle_attr_##name = __ATTR_RO(name) \
throttle_attr(unthrottle, reason[NO_THROTTLE]);
throttle_attr(powercap, reason[POWERCAP]);
throttle_attr(overtemp, reason[CPU_OVERTEMP]);
throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
throttle_attr(overcurrent, reason[OVERCURRENT]);
throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
throttle_attr(turbo_stat, throttle_turbo);
throttle_attr(sub_turbo_stat, throttle_sub_turbo);
static struct attribute *throttle_attrs[] = {
&throttle_attr_unthrottle.attr,
&throttle_attr_powercap.attr,
&throttle_attr_overtemp.attr,
&throttle_attr_supply_fault.attr,
&throttle_attr_overcurrent.attr,
&throttle_attr_occ_reset.attr,
&throttle_attr_turbo_stat.attr,
&throttle_attr_sub_turbo_stat.attr,
NULL,
};
static const struct attribute_group throttle_attr_grp = {
.name = "throttle_stats",
.attrs = throttle_attrs,
};
/* Helper routines */
/* Access helpers to power mgt SPR */
static inline unsigned long get_pmspr(unsigned long sprn)
{
switch (sprn) {
case SPRN_PMCR:
return mfspr(SPRN_PMCR);
case SPRN_PMICR:
return mfspr(SPRN_PMICR);
case SPRN_PMSR:
return mfspr(SPRN_PMSR);
}
BUG();
}
static inline void set_pmspr(unsigned long sprn, unsigned long val)
{
switch (sprn) {
case SPRN_PMCR:
mtspr(SPRN_PMCR, val);
return;
case SPRN_PMICR:
mtspr(SPRN_PMICR, val);
return;
}
BUG();
}
/*
* Use objects of this type to query/update
* pstates on a remote CPU via smp_call_function.
*/
struct powernv_smp_call_data {
unsigned int freq;
int pstate_id;
};
/*
* powernv_read_cpu_freq: Reads the current frequency on this CPU.
*
* Called via smp_call_function.
*
* Note: The caller of the smp_call_function should pass an argument of
* the type 'struct powernv_smp_call_data *' along with this function.
*
* The current frequency on this CPU will be returned via
* ((struct powernv_smp_call_data *)arg)->freq;
*/
static void powernv_read_cpu_freq(void *arg)
{
unsigned long pmspr_val;
s8 local_pstate_id;
struct powernv_smp_call_data *freq_data = arg;
pmspr_val = get_pmspr(SPRN_PMSR);
/*
* The local pstate id corresponds bits 48..55 in the PMSR.
* Note: Watch out for the sign!
*/
local_pstate_id = (pmspr_val >> 48) & 0xFF;
freq_data->pstate_id = local_pstate_id;
freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n",
raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
freq_data->freq);
}
/*
* powernv_cpufreq_get: Returns the CPU frequency as reported by the
* firmware for CPU 'cpu'. This value is reported through the sysfs
* file cpuinfo_cur_freq.
*/
static unsigned int powernv_cpufreq_get(unsigned int cpu)
{
struct powernv_smp_call_data freq_data;
smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
&freq_data, 1);
return freq_data.freq;
}
/*
* set_pstate: Sets the pstate on this CPU.
*
* This is called via an smp_call_function.
*
* The caller must ensure that freq_data is of the type
* (struct powernv_smp_call_data *) and the pstate_id which needs to be set
* on this CPU should be present in freq_data->pstate_id.
*/
static void set_pstate(void *freq_data)
{
unsigned long val;
unsigned long pstate_ul =
((struct powernv_smp_call_data *) freq_data)->pstate_id;
val = get_pmspr(SPRN_PMCR);
val = val & 0x0000FFFFFFFFFFFFULL;
pstate_ul = pstate_ul & 0xFF;
/* Set both global(bits 56..63) and local(bits 48..55) PStates */
val = val | (pstate_ul << 56) | (pstate_ul << 48);
pr_debug("Setting cpu %d pmcr to %016lX\n",
raw_smp_processor_id(), val);
set_pmspr(SPRN_PMCR, val);
}
/*
* get_nominal_index: Returns the index corresponding to the nominal
* pstate in the cpufreq table
*/
static inline unsigned int get_nominal_index(void)
{
return powernv_pstate_info.max - powernv_pstate_info.nominal;
}
static void powernv_cpufreq_throttle_check(void *data)
{
struct chip *chip;
unsigned int cpu = smp_processor_id();
unsigned long pmsr;
int pmsr_pmax;
pmsr = get_pmspr(SPRN_PMSR);
chip = this_cpu_read(chip_info);
/* Check for Pmax Capping */
pmsr_pmax = (s8)PMSR_MAX(pmsr);
if (pmsr_pmax != powernv_pstate_info.max) {
if (chip->throttled)
goto next;
chip->throttled = true;
if (pmsr_pmax < powernv_pstate_info.nominal) {
pr_warn_once("CPU %d on Chip %u has Pmax reduced below nominal frequency (%d < %d)\n",
cpu, chip->id, pmsr_pmax,
powernv_pstate_info.nominal);
chip->throttle_sub_turbo++;
} else {
chip->throttle_turbo++;
}
trace_powernv_throttle(chip->id,
throttle_reason[chip->throttle_reason],
pmsr_pmax);
} else if (chip->throttled) {
chip->throttled = false;
trace_powernv_throttle(chip->id,
throttle_reason[chip->throttle_reason],
pmsr_pmax);
}
/* Check if Psafe_mode_active is set in PMSR. */
next:
if (pmsr & PMSR_PSAFE_ENABLE) {
throttled = true;
pr_info("Pstate set to safe frequency\n");
}
/* Check if SPR_EM_DISABLE is set in PMSR */
if (pmsr & PMSR_SPR_EM_DISABLE) {
throttled = true;
pr_info("Frequency Control disabled from OS\n");
}
if (throttled) {
pr_info("PMSR = %16lx\n", pmsr);
pr_warn("CPU Frequency could be throttled\n");
}
}
/*
* powernv_cpufreq_target_index: Sets the frequency corresponding to
* the cpufreq table entry indexed by new_index on the cpus in the
* mask policy->cpus
*/
static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
unsigned int new_index)
{
struct powernv_smp_call_data freq_data;
if (unlikely(rebooting) && new_index != get_nominal_index())
return 0;
if (!throttled)
powernv_cpufreq_throttle_check(NULL);
freq_data.pstate_id = powernv_freqs[new_index].driver_data;
/*
* Use smp_call_function to send IPI and execute the
* mtspr on target CPU. We could do that without IPI
* if current CPU is within policy->cpus (core)
*/
smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
return 0;
}
static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
int base, i;
base = cpu_first_thread_sibling(policy->cpu);
for (i = 0; i < threads_per_core; i++)
cpumask_set_cpu(base + i, policy->cpus);
if (!policy->driver_data) {
int ret;
ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
if (ret) {
pr_info("Failed to create throttle stats directory for cpu %d\n",
policy->cpu);
return ret;
}
/*
* policy->driver_data is used as a flag for one-time
* creation of throttle sysfs files.
*/
policy->driver_data = policy;
}
return cpufreq_table_validate_and_show(policy, powernv_freqs);
}
static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
unsigned long action, void *unused)
{
int cpu;
struct cpufreq_policy cpu_policy;
rebooting = true;
for_each_online_cpu(cpu) {
cpufreq_get_policy(&cpu_policy, cpu);
powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
}
return NOTIFY_DONE;
}
static struct notifier_block powernv_cpufreq_reboot_nb = {
.notifier_call = powernv_cpufreq_reboot_notifier,
};
void powernv_cpufreq_work_fn(struct work_struct *work)
{
struct chip *chip = container_of(work, struct chip, throttle);
unsigned int cpu;
cpumask_t mask;
get_online_cpus();
cpumask_and(&mask, &chip->mask, cpu_online_mask);
smp_call_function_any(&mask,
powernv_cpufreq_throttle_check, NULL, 0);
if (!chip->restore)
goto out;
chip->restore = false;
for_each_cpu(cpu, &mask) {
int index;
struct cpufreq_policy policy;
cpufreq_get_policy(&policy, cpu);
cpufreq_frequency_table_target(&policy, policy.freq_table,
policy.cur,
CPUFREQ_RELATION_C, &index);
powernv_cpufreq_target_index(&policy, index);
cpumask_andnot(&mask, &mask, policy.cpus);
}
out:
put_online_cpus();
}
static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
unsigned long msg_type, void *_msg)
{
struct opal_msg *msg = _msg;
struct opal_occ_msg omsg;
int i;
if (msg_type != OPAL_MSG_OCC)
return 0;
omsg.type = be64_to_cpu(msg->params[0]);
switch (omsg.type) {
case OCC_RESET:
occ_reset = true;
pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
/*
* powernv_cpufreq_throttle_check() is called in
* target() callback which can detect the throttle state
* for governors like ondemand.
* But static governors will not call target() often thus
* report throttling here.
*/
if (!throttled) {
throttled = true;
pr_warn("CPU frequency is throttled for duration\n");
}
break;
case OCC_LOAD:
pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
break;
case OCC_THROTTLE:
omsg.chip = be64_to_cpu(msg->params[1]);
omsg.throttle_status = be64_to_cpu(msg->params[2]);
if (occ_reset) {
occ_reset = false;
throttled = false;
pr_info("OCC Active, CPU frequency is no longer throttled\n");
for (i = 0; i < nr_chips; i++) {
chips[i].restore = true;
schedule_work(&chips[i].throttle);
}
return 0;
}
for (i = 0; i < nr_chips; i++)
if (chips[i].id == omsg.chip)
break;
if (omsg.throttle_status >= 0 &&
omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
chips[i].throttle_reason = omsg.throttle_status;
chips[i].reason[omsg.throttle_status]++;
}
if (!omsg.throttle_status)
chips[i].restore = true;
schedule_work(&chips[i].throttle);
}
return 0;
}
static struct notifier_block powernv_cpufreq_opal_nb = {
.notifier_call = powernv_cpufreq_occ_msg,
.next = NULL,
.priority = 0,
};
static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
{
struct powernv_smp_call_data freq_data;
freq_data.pstate_id = powernv_pstate_info.min;
smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
}
static struct cpufreq_driver powernv_cpufreq_driver = {
.name = "powernv-cpufreq",
.flags = CPUFREQ_CONST_LOOPS,
.init = powernv_cpufreq_cpu_init,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = powernv_cpufreq_target_index,
.get = powernv_cpufreq_get,
.stop_cpu = powernv_cpufreq_stop_cpu,
.attr = powernv_cpu_freq_attr,
};
static int init_chip_info(void)
{
unsigned int chip[256];
unsigned int cpu, i;
unsigned int prev_chip_id = UINT_MAX;
for_each_possible_cpu(cpu) {
unsigned int id = cpu_to_chip_id(cpu);
if (prev_chip_id != id) {
prev_chip_id = id;
chip[nr_chips++] = id;
}
}
chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
if (!chips)
return -ENOMEM;
for (i = 0; i < nr_chips; i++) {
chips[i].id = chip[i];
cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
for_each_cpu(cpu, &chips[i].mask)
per_cpu(chip_info, cpu) = &chips[i];
}
return 0;
}
static inline void clean_chip_info(void)
{
kfree(chips);
}
static inline void unregister_all_notifiers(void)
{
opal_message_notifier_unregister(OPAL_MSG_OCC,
&powernv_cpufreq_opal_nb);
unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
}
static int __init powernv_cpufreq_init(void)
{
int rc = 0;
/* Don't probe on pseries (guest) platforms */
if (!firmware_has_feature(FW_FEATURE_OPAL))
return -ENODEV;
/* Discover pstates from device tree and init */
rc = init_powernv_pstates();
if (rc)
goto out;
/* Populate chip info */
rc = init_chip_info();
if (rc)
goto out;
register_reboot_notifier(&powernv_cpufreq_reboot_nb);
opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
rc = cpufreq_register_driver(&powernv_cpufreq_driver);
if (!rc)
return 0;
pr_info("Failed to register the cpufreq driver (%d)\n", rc);
unregister_all_notifiers();
clean_chip_info();
out:
pr_info("Platform driver disabled. System does not support PState control\n");
return rc;
}
module_init(powernv_cpufreq_init);
static void __exit powernv_cpufreq_exit(void)
{
cpufreq_unregister_driver(&powernv_cpufreq_driver);
unregister_all_notifiers();
clean_chip_info();
}
module_exit(powernv_cpufreq_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");