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>
19 #include <asm/runlatch.h>
21 /* Flags and constants used in PowerNV platform */
23 #define MAX_POWERNV_IDLE_STATES 8
24 #define IDLE_USE_INST_NAP 0x00010000 /* Use nap instruction */
25 #define IDLE_USE_INST_SLEEP 0x00020000 /* Use sleep instruction */
27 struct cpuidle_driver powernv_idle_driver = {
28 .name = "powernv_idle",
32 static int max_idle_state;
33 static struct cpuidle_state *cpuidle_state_table;
35 static int snooze_loop(struct cpuidle_device *dev,
36 struct cpuidle_driver *drv,
40 set_thread_flag(TIF_POLLING_NRFLAG);
43 while (!need_resched()) {
50 clear_thread_flag(TIF_POLLING_NRFLAG);
55 static int nap_loop(struct cpuidle_device *dev,
56 struct cpuidle_driver *drv,
65 static int fastsleep_loop(struct cpuidle_device *dev,
66 struct cpuidle_driver *drv,
69 unsigned long old_lpcr = mfspr(SPRN_LPCR);
70 unsigned long new_lpcr;
72 if (unlikely(system_state < SYSTEM_RUNNING))
76 new_lpcr &= ~(LPCR_MER | LPCR_PECE); /* lpcr[mer] must be 0 */
78 /* exit powersave upon external interrupt, but not decrementer
81 new_lpcr |= LPCR_PECE0;
83 mtspr(SPRN_LPCR, new_lpcr);
86 mtspr(SPRN_LPCR, old_lpcr);
92 * States for dedicated partition case.
94 static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
98 .flags = CPUIDLE_FLAG_TIME_VALID,
100 .target_residency = 0,
101 .enter = &snooze_loop },
104 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
105 unsigned long action, void *hcpu)
107 int hotcpu = (unsigned long)hcpu;
108 struct cpuidle_device *dev =
109 per_cpu(cpuidle_devices, hotcpu);
111 if (dev && cpuidle_get_driver()) {
114 case CPU_ONLINE_FROZEN:
115 cpuidle_pause_and_lock();
116 cpuidle_enable_device(dev);
117 cpuidle_resume_and_unlock();
121 case CPU_DEAD_FROZEN:
122 cpuidle_pause_and_lock();
123 cpuidle_disable_device(dev);
124 cpuidle_resume_and_unlock();
134 static struct notifier_block setup_hotplug_notifier = {
135 .notifier_call = powernv_cpuidle_add_cpu_notifier,
139 * powernv_cpuidle_driver_init()
141 static int powernv_cpuidle_driver_init(void)
144 struct cpuidle_driver *drv = &powernv_idle_driver;
146 drv->state_count = 0;
148 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
149 /* Is the state not enabled? */
150 if (cpuidle_state_table[idle_state].enter == NULL)
153 drv->states[drv->state_count] = /* structure copy */
154 cpuidle_state_table[idle_state];
156 drv->state_count += 1;
162 static int powernv_add_idle_states(void)
164 struct device_node *power_mgt;
165 struct property *prop;
166 int nr_idle_states = 1; /* Snooze */
171 /* Currently we have snooze statically defined */
173 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
175 pr_warn("opal: PowerMgmt Node not found\n");
176 return nr_idle_states;
179 prop = of_find_property(power_mgt, "ibm,cpu-idle-state-flags", NULL);
181 pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
182 return nr_idle_states;
185 dt_idle_states = prop->length / sizeof(u32);
186 flags = (u32 *) prop->value;
188 for (i = 0; i < dt_idle_states; i++) {
190 if (flags[i] & IDLE_USE_INST_NAP) {
192 strcpy(powernv_states[nr_idle_states].name, "Nap");
193 strcpy(powernv_states[nr_idle_states].desc, "Nap");
194 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID;
195 powernv_states[nr_idle_states].exit_latency = 10;
196 powernv_states[nr_idle_states].target_residency = 100;
197 powernv_states[nr_idle_states].enter = &nap_loop;
201 if (flags[i] & IDLE_USE_INST_SLEEP) {
202 /* Add FASTSLEEP state */
203 strcpy(powernv_states[nr_idle_states].name, "FastSleep");
204 strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
205 powernv_states[nr_idle_states].flags =
206 CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TIMER_STOP;
207 powernv_states[nr_idle_states].exit_latency = 300;
208 powernv_states[nr_idle_states].target_residency = 1000000;
209 powernv_states[nr_idle_states].enter = &fastsleep_loop;
214 return nr_idle_states;
218 * powernv_idle_probe()
219 * Choose state table for shared versus dedicated partition
221 static int powernv_idle_probe(void)
223 if (cpuidle_disable != IDLE_NO_OVERRIDE)
226 if (firmware_has_feature(FW_FEATURE_OPALv3)) {
227 cpuidle_state_table = powernv_states;
228 /* Device tree can indicate more idle states */
229 max_idle_state = powernv_add_idle_states();
236 static int __init powernv_processor_idle_init(void)
240 retval = powernv_idle_probe();
244 powernv_cpuidle_driver_init();
245 retval = cpuidle_register(&powernv_idle_driver, NULL);
247 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
251 register_cpu_notifier(&setup_hotplug_notifier);
252 printk(KERN_DEBUG "powernv_idle_driver registered\n");
256 device_initcall(powernv_processor_idle_init);