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path: root/drivers/cpuidle/cpuidle-powernv.c
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-rw-r--r--drivers/cpuidle/cpuidle-powernv.c406
1 files changed, 406 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
new file mode 100644
index 0000000000..9ebedd972d
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -0,0 +1,406 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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 __read_mostly;
+static struct cpuidle_state *cpuidle_state_table __read_mostly;
+
+struct stop_psscr_table {
+ u64 val;
+ u64 mask;
+};
+
+static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly;
+
+static u64 default_snooze_timeout __read_mostly;
+static bool snooze_timeout_en __read_mostly;
+
+static u64 get_snooze_timeout(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv,
+ int index)
+{
+ int i;
+
+ if (unlikely(!snooze_timeout_en))
+ return default_snooze_timeout;
+
+ for (i = index + 1; i < drv->state_count; i++) {
+ if (dev->states_usage[i].disable)
+ continue;
+
+ return drv->states[i].target_residency * tb_ticks_per_usec;
+ }
+
+ return default_snooze_timeout;
+}
+
+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() + get_snooze_timeout(dev, drv, index);
+ dev->poll_time_limit = false;
+ ppc64_runlatch_off();
+ HMT_very_low();
+ while (!need_resched()) {
+ if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) {
+ /*
+ * Task has not woken up but we are exiting the polling
+ * loop anyway. Require a barrier after polling is
+ * cleared to order subsequent test of need_resched().
+ */
+ clear_thread_flag(TIF_POLLING_NRFLAG);
+ dev->poll_time_limit = true;
+ smp_mb();
+ break;
+ }
+ }
+
+ HMT_medium();
+ ppc64_runlatch_on();
+ clear_thread_flag(TIF_POLLING_NRFLAG);
+
+ local_irq_disable();
+
+ 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)
+{
+ arch300_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,
+ .flags = CPUIDLE_FLAG_POLLING },
+};
+
+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)
+{
+ strscpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
+ strscpy(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;
+ /* For power8 and below psscr_* will be 0 */
+ stop_psscr_table[index].val = psscr_val;
+ stop_psscr_table[index].mask = psscr_mask;
+}
+
+extern u32 pnv_get_supported_cpuidle_states(void);
+static int powernv_add_idle_states(void)
+{
+ int nr_idle_states = 1; /* Snooze */
+ int dt_idle_states;
+ u32 has_stop_states = 0;
+ int i;
+ u32 supported_flags = pnv_get_supported_cpuidle_states();
+
+
+ /* Currently we have snooze statically defined */
+ if (nr_pnv_idle_states <= 0) {
+ pr_warn("cpuidle-powernv : Only Snooze is available\n");
+ goto out;
+ }
+
+ /* TODO: Count only states which are eligible for cpuidle */
+ dt_idle_states = nr_pnv_idle_states;
+
+ /*
+ * Since snooze is used as first idle state, max idle states allowed is
+ * CPUIDLE_STATE_MAX -1
+ */
+ if (nr_pnv_idle_states > CPUIDLE_STATE_MAX - 1) {
+ pr_warn("cpuidle-powernv: discovered idle states more than allowed");
+ dt_idle_states = CPUIDLE_STATE_MAX - 1;
+ }
+
+ /*
+ * 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 = (pnv_idle_states[0].flags &
+ (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
+
+ for (i = 0; i < dt_idle_states; i++) {
+ unsigned int exit_latency, target_residency;
+ bool stops_timebase = false;
+ struct pnv_idle_states_t *state = &pnv_idle_states[i];
+
+ /*
+ * Skip the platform idle state whose flag isn't in
+ * the supported_cpuidle_states flag mask.
+ */
+ if ((state->flags & supported_flags) != state->flags)
+ continue;
+ /*
+ * If an idle state has exit latency beyond
+ * POWERNV_THRESHOLD_LATENCY_NS then don't use it
+ * in cpu-idle.
+ */
+ if (state->latency_ns > POWERNV_THRESHOLD_LATENCY_NS)
+ continue;
+ /*
+ * Firmware passes residency and latency values in ns.
+ * cpuidle expects it in us.
+ */
+ exit_latency = DIV_ROUND_UP(state->latency_ns, 1000);
+ target_residency = DIV_ROUND_UP(state->residency_ns, 1000);
+
+ if (has_stop_states && !(state->valid))
+ continue;
+
+ if (state->flags & OPAL_PM_TIMEBASE_STOP)
+ stops_timebase = true;
+
+ if (state->flags & OPAL_PM_NAP_ENABLED) {
+ /* 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, state->name,
+ CPUIDLE_FLAG_NONE, stop_loop,
+ target_residency, exit_latency,
+ state->psscr_val,
+ state->psscr_mask);
+ }
+
+ /*
+ * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
+ * within this config dependency check.
+ */
+#ifdef CONFIG_TICK_ONESHOT
+ else if (state->flags & OPAL_PM_SLEEP_ENABLED ||
+ state->flags & OPAL_PM_SLEEP_ENABLED_ER1) {
+ /* 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, state->name,
+ CPUIDLE_FLAG_TIMER_STOP, stop_loop,
+ target_residency, exit_latency,
+ state->psscr_val,
+ state->psscr_mask);
+ }
+#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();
+ default_snooze_timeout = TICK_USEC * tb_ticks_per_usec;
+ if (max_idle_state > 1)
+ snooze_timeout_en = true;
+ } 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);