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>
16 #include <linux/slab.h>
18 #include <asm/machdep.h>
19 #include <asm/firmware.h>
21 #include <asm/runlatch.h>
23 #define MAX_POWERNV_IDLE_STATES 8
25 struct cpuidle_driver powernv_idle_driver = {
26 .name = "powernv_idle",
30 static int max_idle_state;
31 static struct cpuidle_state *cpuidle_state_table;
33 static int snooze_loop(struct cpuidle_device *dev,
34 struct cpuidle_driver *drv,
38 set_thread_flag(TIF_POLLING_NRFLAG);
41 while (!need_resched()) {
48 clear_thread_flag(TIF_POLLING_NRFLAG);
53 static int nap_loop(struct cpuidle_device *dev,
54 struct cpuidle_driver *drv,
63 static int fastsleep_loop(struct cpuidle_device *dev,
64 struct cpuidle_driver *drv,
67 unsigned long old_lpcr = mfspr(SPRN_LPCR);
68 unsigned long new_lpcr;
70 if (unlikely(system_state < SYSTEM_RUNNING))
74 /* Do not exit powersave upon decrementer as we've setup the timer
77 new_lpcr &= ~LPCR_PECE1;
79 mtspr(SPRN_LPCR, new_lpcr);
82 mtspr(SPRN_LPCR, old_lpcr);
88 * States for dedicated partition case.
90 static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
95 .target_residency = 0,
96 .enter = &snooze_loop },
99 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
100 unsigned long action, void *hcpu)
102 int hotcpu = (unsigned long)hcpu;
103 struct cpuidle_device *dev =
104 per_cpu(cpuidle_devices, hotcpu);
106 if (dev && cpuidle_get_driver()) {
109 case CPU_ONLINE_FROZEN:
110 cpuidle_pause_and_lock();
111 cpuidle_enable_device(dev);
112 cpuidle_resume_and_unlock();
116 case CPU_DEAD_FROZEN:
117 cpuidle_pause_and_lock();
118 cpuidle_disable_device(dev);
119 cpuidle_resume_and_unlock();
129 static struct notifier_block setup_hotplug_notifier = {
130 .notifier_call = powernv_cpuidle_add_cpu_notifier,
134 * powernv_cpuidle_driver_init()
136 static int powernv_cpuidle_driver_init(void)
139 struct cpuidle_driver *drv = &powernv_idle_driver;
141 drv->state_count = 0;
143 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
144 /* Is the state not enabled? */
145 if (cpuidle_state_table[idle_state].enter == NULL)
148 drv->states[drv->state_count] = /* structure copy */
149 cpuidle_state_table[idle_state];
151 drv->state_count += 1;
157 static int powernv_add_idle_states(void)
159 struct device_node *power_mgt;
160 int nr_idle_states = 1; /* Snooze */
162 u32 *latency_ns, *residency_ns, *flags;
165 /* Currently we have snooze statically defined */
167 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
169 pr_warn("opal: PowerMgmt Node not found\n");
173 /* Read values of any property to determine the num of idle states */
174 dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
175 if (dt_idle_states < 0) {
176 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
180 flags = kzalloc(sizeof(*flags) * dt_idle_states, GFP_KERNEL);
181 if (of_property_read_u32_array(power_mgt,
182 "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
183 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
187 latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL);
188 rc = of_property_read_u32_array(power_mgt,
189 "ibm,cpu-idle-state-latencies-ns", latency_ns, dt_idle_states);
191 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
192 goto out_free_latency;
195 residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL);
196 rc = of_property_read_u32_array(power_mgt,
197 "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
199 for (i = 0; i < dt_idle_states; i++) {
202 * Cpuidle accepts exit_latency and target_residency in us.
203 * Use default target_residency values if f/w does not expose it.
205 if (flags[i] & OPAL_PM_NAP_ENABLED) {
207 strcpy(powernv_states[nr_idle_states].name, "Nap");
208 strcpy(powernv_states[nr_idle_states].desc, "Nap");
209 powernv_states[nr_idle_states].flags = 0;
210 powernv_states[nr_idle_states].target_residency = 100;
211 powernv_states[nr_idle_states].enter = &nap_loop;
212 } else if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
213 flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
214 /* Add FASTSLEEP state */
215 strcpy(powernv_states[nr_idle_states].name, "FastSleep");
216 strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
217 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
218 powernv_states[nr_idle_states].target_residency = 300000;
219 powernv_states[nr_idle_states].enter = &fastsleep_loop;
222 powernv_states[nr_idle_states].exit_latency =
223 ((unsigned int)latency_ns[i]) / 1000;
226 powernv_states[nr_idle_states].target_residency =
227 ((unsigned int)residency_ns[i]) / 1000;
239 return nr_idle_states;
243 * powernv_idle_probe()
244 * Choose state table for shared versus dedicated partition
246 static int powernv_idle_probe(void)
248 if (cpuidle_disable != IDLE_NO_OVERRIDE)
251 if (firmware_has_feature(FW_FEATURE_OPALv3)) {
252 cpuidle_state_table = powernv_states;
253 /* Device tree can indicate more idle states */
254 max_idle_state = powernv_add_idle_states();
261 static int __init powernv_processor_idle_init(void)
265 retval = powernv_idle_probe();
269 powernv_cpuidle_driver_init();
270 retval = cpuidle_register(&powernv_idle_driver, NULL);
272 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
276 register_cpu_notifier(&setup_hotplug_notifier);
277 printk(KERN_DEBUG "powernv_idle_driver registered\n");
281 device_initcall(powernv_processor_idle_init);