2 * cpuidle-powernv - idle state cpuidle driver.
3 * Adapted from drivers/cpuidle/cpuidle-pseries
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/moduleparam.h>
11 #include <linux/cpuidle.h>
12 #include <linux/cpu.h>
13 #include <linux/notifier.h>
14 #include <linux/clockchips.h>
17 #include <asm/machdep.h>
18 #include <asm/firmware.h>
20 #include <asm/runlatch.h>
22 #define MAX_POWERNV_IDLE_STATES 8
24 struct cpuidle_driver powernv_idle_driver = {
25 .name = "powernv_idle",
29 static int max_idle_state;
30 static struct cpuidle_state *cpuidle_state_table;
32 static int snooze_loop(struct cpuidle_device *dev,
33 struct cpuidle_driver *drv,
37 set_thread_flag(TIF_POLLING_NRFLAG);
40 while (!need_resched()) {
47 clear_thread_flag(TIF_POLLING_NRFLAG);
52 static int nap_loop(struct cpuidle_device *dev,
53 struct cpuidle_driver *drv,
62 static int fastsleep_loop(struct cpuidle_device *dev,
63 struct cpuidle_driver *drv,
66 unsigned long old_lpcr = mfspr(SPRN_LPCR);
67 unsigned long new_lpcr;
69 if (unlikely(system_state < SYSTEM_RUNNING))
73 /* Do not exit powersave upon decrementer as we've setup the timer
76 new_lpcr &= ~LPCR_PECE1;
78 mtspr(SPRN_LPCR, new_lpcr);
81 mtspr(SPRN_LPCR, old_lpcr);
87 * States for dedicated partition case.
89 static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
94 .target_residency = 0,
95 .enter = &snooze_loop },
98 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
99 unsigned long action, void *hcpu)
101 int hotcpu = (unsigned long)hcpu;
102 struct cpuidle_device *dev =
103 per_cpu(cpuidle_devices, hotcpu);
105 if (dev && cpuidle_get_driver()) {
108 case CPU_ONLINE_FROZEN:
109 cpuidle_pause_and_lock();
110 cpuidle_enable_device(dev);
111 cpuidle_resume_and_unlock();
115 case CPU_DEAD_FROZEN:
116 cpuidle_pause_and_lock();
117 cpuidle_disable_device(dev);
118 cpuidle_resume_and_unlock();
128 static struct notifier_block setup_hotplug_notifier = {
129 .notifier_call = powernv_cpuidle_add_cpu_notifier,
133 * powernv_cpuidle_driver_init()
135 static int powernv_cpuidle_driver_init(void)
138 struct cpuidle_driver *drv = &powernv_idle_driver;
140 drv->state_count = 0;
142 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
143 /* Is the state not enabled? */
144 if (cpuidle_state_table[idle_state].enter == NULL)
147 drv->states[drv->state_count] = /* structure copy */
148 cpuidle_state_table[idle_state];
150 drv->state_count += 1;
156 static int powernv_add_idle_states(void)
158 struct device_node *power_mgt;
159 int nr_idle_states = 1; /* Snooze */
161 const __be32 *idle_state_flags;
162 const __be32 *idle_state_latency;
163 u32 len_flags, flags, latency_ns;
166 /* Currently we have snooze statically defined */
168 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
170 pr_warn("opal: PowerMgmt Node not found\n");
171 return nr_idle_states;
174 idle_state_flags = of_get_property(power_mgt, "ibm,cpu-idle-state-flags", &len_flags);
175 if (!idle_state_flags) {
176 pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
177 return nr_idle_states;
180 idle_state_latency = of_get_property(power_mgt,
181 "ibm,cpu-idle-state-latencies-ns", NULL);
182 if (!idle_state_latency) {
183 pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n");
184 return nr_idle_states;
187 dt_idle_states = len_flags / sizeof(u32);
189 for (i = 0; i < dt_idle_states; i++) {
191 flags = be32_to_cpu(idle_state_flags[i]);
193 /* Cpuidle accepts exit_latency in us and we estimate
194 * target residency to be 10x exit_latency
196 latency_ns = be32_to_cpu(idle_state_latency[i]);
197 if (flags & OPAL_PM_NAP_ENABLED) {
199 strcpy(powernv_states[nr_idle_states].name, "Nap");
200 strcpy(powernv_states[nr_idle_states].desc, "Nap");
201 powernv_states[nr_idle_states].flags = 0;
202 powernv_states[nr_idle_states].exit_latency =
203 ((unsigned int)latency_ns) / 1000;
204 powernv_states[nr_idle_states].target_residency =
205 ((unsigned int)latency_ns / 100);
206 powernv_states[nr_idle_states].enter = &nap_loop;
210 if (flags & OPAL_PM_SLEEP_ENABLED ||
211 flags & OPAL_PM_SLEEP_ENABLED_ER1) {
212 /* Add FASTSLEEP state */
213 strcpy(powernv_states[nr_idle_states].name, "FastSleep");
214 strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
215 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
216 powernv_states[nr_idle_states].exit_latency =
217 ((unsigned int)latency_ns) / 1000;
218 powernv_states[nr_idle_states].target_residency =
219 ((unsigned int)latency_ns / 100);
220 powernv_states[nr_idle_states].enter = &fastsleep_loop;
225 return nr_idle_states;
229 * powernv_idle_probe()
230 * Choose state table for shared versus dedicated partition
232 static int powernv_idle_probe(void)
234 if (cpuidle_disable != IDLE_NO_OVERRIDE)
237 if (firmware_has_feature(FW_FEATURE_OPALv3)) {
238 cpuidle_state_table = powernv_states;
239 /* Device tree can indicate more idle states */
240 max_idle_state = powernv_add_idle_states();
247 static int __init powernv_processor_idle_init(void)
251 retval = powernv_idle_probe();
255 powernv_cpuidle_driver_init();
256 retval = cpuidle_register(&powernv_idle_driver, NULL);
258 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
262 register_cpu_notifier(&setup_hotplug_notifier);
263 printk(KERN_DEBUG "powernv_idle_driver registered\n");
267 device_initcall(powernv_processor_idle_init);