/*
* cpuidle-powernv - idle state cpuidle driver.
* Adapted from drivers/cpuidle/cpuidle-pseries
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/cpuidle.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/clockchips.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/opal.h>
#include <asm/runlatch.h>
#include <asm/cpuidle.h>
/*
* Expose only those Hardware idle states via the cpuidle framework
* that have latency value below POWERNV_THRESHOLD_LATENCY_NS.
*/
#define POWERNV_THRESHOLD_LATENCY_NS 200000
static struct cpuidle_driver powernv_idle_driver = {
.name = "powernv_idle",
.owner = THIS_MODULE,
};
static int max_idle_state;
static struct cpuidle_state *cpuidle_state_table;
struct stop_psscr_table {
u64 val;
u64 mask;
};
static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX];
static u64 snooze_timeout;
static bool snooze_timeout_en;
static int snooze_loop(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
u64 snooze_exit_time;
set_thread_flag(TIF_POLLING_NRFLAG);
local_irq_enable();
snooze_exit_time = get_tb() + snooze_timeout;
ppc64_runlatch_off();
HMT_very_low();
while (!need_resched()) {
if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time)
break;
}
HMT_medium();
ppc64_runlatch_on();
clear_thread_flag(TIF_POLLING_NRFLAG);
smp_mb();
return index;
}
static int nap_loop(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
power7_idle_type(PNV_THREAD_NAP);
return index;
}
/* Register for fastsleep only in oneshot mode of broadcast */
#ifdef CONFIG_TICK_ONESHOT
static int fastsleep_loop(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
unsigned long old_lpcr = mfspr(SPRN_LPCR);
unsigned long new_lpcr;
if (unlikely(system_state < SYSTEM_RUNNING))
return index;
new_lpcr = old_lpcr;
/* Do not exit powersave upon decrementer as we've setup the timer
* offload.
*/
new_lpcr &= ~LPCR_PECE1;
mtspr(SPRN_LPCR, new_lpcr);
power7_idle_type(PNV_THREAD_SLEEP);
mtspr(SPRN_LPCR, old_lpcr);
return index;
}
#endif
static int stop_loop(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
power9_idle_type(stop_psscr_table[index].val,
stop_psscr_table[index].mask);
return index;
}
/*
* States for dedicated partition case.
*/
static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = {
{ /* Snooze */
.name = "snooze",
.desc = "snooze",
.exit_latency = 0,
.target_residency = 0,
.enter = snooze_loop },
};
static int powernv_cpuidle_cpu_online(unsigned int cpu)
{
struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
if (dev && cpuidle_get_driver()) {
cpuidle_pause_and_lock();
cpuidle_enable_device(dev);
cpuidle_resume_and_unlock();
}
return 0;
}
static int powernv_cpuidle_cpu_dead(unsigned int cpu)
{
struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
if (dev && cpuidle_get_driver()) {
cpuidle_pause_and_lock();
cpuidle_disable_device(dev);
cpuidle_resume_and_unlock();
}
return 0;
}
/*
* powernv_cpuidle_driver_init()
*/
static int powernv_cpuidle_driver_init(void)
{
int idle_state;
struct cpuidle_driver *drv = &powernv_idle_driver;
drv->state_count = 0;
for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
/* Is the state not enabled? */
if (cpuidle_state_table[idle_state].enter == NULL)
continue;
drv->states[drv->state_count] = /* structure copy */
cpuidle_state_table[idle_state];
drv->state_count += 1;
}
/*
* On the PowerNV platform cpu_present may be less than cpu_possible in
* cases when firmware detects the CPU, but it is not available to the
* OS. If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at
* run time and hence cpu_devices are not created for those CPUs by the
* generic topology_init().
*
* drv->cpumask defaults to cpu_possible_mask in
* __cpuidle_driver_init(). This breaks cpuidle on PowerNV where
* cpu_devices are not created for CPUs in cpu_possible_mask that
* cannot be hot-added later at run time.
*
* Trying cpuidle_register_device() on a CPU without a cpu_device is
* incorrect, so pass a correct CPU mask to the generic cpuidle driver.
*/
drv->cpumask = (struct cpumask *)cpu_present_mask;
return 0;
}
static inline void add_powernv_state(int index, const char *name,
unsigned int flags,
int (*idle_fn)(struct cpuidle_device *,
struct cpuidle_driver *,
int),
unsigned int target_residency,
unsigned int exit_latency,
u64 psscr_val, u64 psscr_mask)
{
strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
powernv_states[index].flags = flags;
powernv_states[index].target_residency = target_residency;
powernv_states[index].exit_latency = exit_latency;
powernv_states[index].enter = idle_fn;
stop_psscr_table[index].val = psscr_val;
stop_psscr_table[index].mask = psscr_mask;
}
/*
* Returns 0 if prop1_len == prop2_len. Else returns -1
*/
static inline int validate_dt_prop_sizes(const char *prop1, int prop1_len,
const char *prop2, int prop2_len)
{
if (prop1_len == prop2_len)
return 0;
pr_warn("cpuidle-powernv: array sizes don't match for %s and %s\n",
prop1, prop2);
return -1;
}
static int powernv_add_idle_states(void)
{
struct device_node *power_mgt;
int nr_idle_states = 1; /* Snooze */
int dt_idle_states, count;
u32 latency_ns[CPUIDLE_STATE_MAX];
u32 residency_ns[CPUIDLE_STATE_MAX];
u32 flags[CPUIDLE_STATE_MAX];
u64 psscr_val[CPUIDLE_STATE_MAX];
u64 psscr_mask[CPUIDLE_STATE_MAX];
const char *names[CPUIDLE_STATE_MAX];
u32 has_stop_states = 0;
int i, rc;
/* Currently we have snooze statically defined */
power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
if (!power_mgt) {
pr_warn("opal: PowerMgmt Node not found\n");
goto out;
}
/* Read values of any property to determine the num of idle states */
dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
if (dt_idle_states < 0) {
pr_warn("cpuidle-powernv: no idle states found in the DT\n");
goto out;
}
count = of_property_count_u32_elems(power_mgt,
"ibm,cpu-idle-state-latencies-ns");
if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
"ibm,cpu-idle-state-latencies-ns",
count) != 0)
goto out;
count = of_property_count_strings(power_mgt,
"ibm,cpu-idle-state-names");
if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
"ibm,cpu-idle-state-names",
count) != 0)
goto out;
/*
* Since snooze is used as first idle state, max idle states allowed is
* CPUIDLE_STATE_MAX -1
*/
if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
pr_warn("cpuidle-powernv: discovered idle states more than allowed");
dt_idle_states = CPUIDLE_STATE_MAX - 1;
}
if (of_property_read_u32_array(power_mgt,
"ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
goto out;
}
if (of_property_read_u32_array(power_mgt,
"ibm,cpu-idle-state-latencies-ns", latency_ns,
dt_idle_states)) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
goto out;
}
if (of_property_read_string_array(power_mgt,
"ibm,cpu-idle-state-names", names, dt_idle_states) < 0) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
goto out;
}
/*
* If the idle states use stop instruction, probe for psscr values
* and psscr mask which are necessary to specify required stop level.
*/
has_stop_states = (flags[0] &
(OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
if (has_stop_states) {
count = of_property_count_u64_elems(power_mgt,
"ibm,cpu-idle-state-psscr");
if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
dt_idle_states,
"ibm,cpu-idle-state-psscr",
count) != 0)
goto out;
count = of_property_count_u64_elems(power_mgt,
"ibm,cpu-idle-state-psscr-mask");
if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
dt_idle_states,
"ibm,cpu-idle-state-psscr-mask",
count) != 0)
goto out;
if (of_property_read_u64_array(power_mgt,
"ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
goto out;
}
if (of_property_read_u64_array(power_mgt,
"ibm,cpu-idle-state-psscr-mask",
psscr_mask, dt_idle_states)) {
pr_warn("cpuidle-powernv:Missing ibm,cpu-idle-state-psscr-mask in DT\n");
goto out;
}
}
count = of_property_count_u32_elems(power_mgt,
"ibm,cpu-idle-state-residency-ns");
if (count < 0) {
rc = count;
} else if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
dt_idle_states,
"ibm,cpu-idle-state-residency-ns",
count) != 0) {
goto out;
} else {
rc = of_property_read_u32_array(power_mgt,
"ibm,cpu-idle-state-residency-ns",
residency_ns, dt_idle_states);
}
for (i = 0; i < dt_idle_states; i++) {
unsigned int exit_latency, target_residency;
bool stops_timebase = false;
/*
* If an idle state has exit latency beyond
* POWERNV_THRESHOLD_LATENCY_NS then don't use it
* in cpu-idle.
*/
if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
continue;
/*
* Firmware passes residency and latency values in ns.
* cpuidle expects it in us.
*/
exit_latency = latency_ns[i] / 1000;
if (!rc)
target_residency = residency_ns[i] / 1000;
else
target_residency = 0;
if (has_stop_states) {
int err = validate_psscr_val_mask(&psscr_val[i],
&psscr_mask[i],
flags[i]);
if (err) {
report_invalid_psscr_val(psscr_val[i], err);
continue;
}
}
if (flags[i] & OPAL_PM_TIMEBASE_STOP)
stops_timebase = true;
/*
* For nap and fastsleep, use default target_residency
* values if f/w does not expose it.
*/
if (flags[i] & OPAL_PM_NAP_ENABLED) {
if (!rc)
target_residency = 100;
/* Add NAP state */
add_powernv_state(nr_idle_states, "Nap",
CPUIDLE_FLAG_NONE, nap_loop,
target_residency, exit_latency, 0, 0);
} else if (has_stop_states && !stops_timebase) {
add_powernv_state(nr_idle_states, names[i],
CPUIDLE_FLAG_NONE, stop_loop,
target_residency, exit_latency,
psscr_val[i], psscr_mask[i]);
}
/*
* All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
* within this config dependency check.
*/
#ifdef CONFIG_TICK_ONESHOT
else if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
if (!rc)
target_residency = 300000;
/* Add FASTSLEEP state */
add_powernv_state(nr_idle_states, "FastSleep",
CPUIDLE_FLAG_TIMER_STOP,
fastsleep_loop,
target_residency, exit_latency, 0, 0);
} else if (has_stop_states && stops_timebase) {
add_powernv_state(nr_idle_states, names[i],
CPUIDLE_FLAG_TIMER_STOP, stop_loop,
target_residency, exit_latency,
psscr_val[i], psscr_mask[i]);
}
#endif
else
continue;
nr_idle_states++;
}
out:
return nr_idle_states;
}
/*
* powernv_idle_probe()
* Choose state table for shared versus dedicated partition
*/
static int powernv_idle_probe(void)
{
if (cpuidle_disable != IDLE_NO_OVERRIDE)
return -ENODEV;
if (firmware_has_feature(FW_FEATURE_OPAL)) {
cpuidle_state_table = powernv_states;
/* Device tree can indicate more idle states */
max_idle_state = powernv_add_idle_states();
if (max_idle_state > 1) {
snooze_timeout_en = true;
snooze_timeout = powernv_states[1].target_residency *
tb_ticks_per_usec;
}
} else
return -ENODEV;
return 0;
}
static int __init powernv_processor_idle_init(void)
{
int retval;
retval = powernv_idle_probe();
if (retval)
return retval;
powernv_cpuidle_driver_init();
retval = cpuidle_register(&powernv_idle_driver, NULL);
if (retval) {
printk(KERN_DEBUG "Registration of powernv driver failed.\n");
return retval;
}
retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
"cpuidle/powernv:online",
powernv_cpuidle_cpu_online, NULL);
WARN_ON(retval < 0);
retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD,
"cpuidle/powernv:dead", NULL,
powernv_cpuidle_cpu_dead);
WARN_ON(retval < 0);
printk(KERN_DEBUG "powernv_idle_driver registered\n");
return 0;
}
device_initcall(powernv_processor_idle_init);
