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 POWERNV_THRESHOLD_LATENCY_NS 200000
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 u64 stop_psscr_table[CPUIDLE_STATE_MAX];
35 static u64 snooze_timeout;
36 static bool snooze_timeout_en;
38 static int snooze_loop(struct cpuidle_device *dev,
39 struct cpuidle_driver *drv,
45 set_thread_flag(TIF_POLLING_NRFLAG);
47 snooze_exit_time = get_tb() + snooze_timeout;
49 while (!need_resched()) {
52 if (snooze_timeout_en && get_tb() > snooze_exit_time)
58 clear_thread_flag(TIF_POLLING_NRFLAG);
63 static int nap_loop(struct cpuidle_device *dev,
64 struct cpuidle_driver *drv,
73 /* Register for fastsleep only in oneshot mode of broadcast */
74 #ifdef CONFIG_TICK_ONESHOT
75 static int fastsleep_loop(struct cpuidle_device *dev,
76 struct cpuidle_driver *drv,
79 unsigned long old_lpcr = mfspr(SPRN_LPCR);
80 unsigned long new_lpcr;
82 if (unlikely(system_state < SYSTEM_RUNNING))
86 /* Do not exit powersave upon decrementer as we've setup the timer
89 new_lpcr &= ~LPCR_PECE1;
91 mtspr(SPRN_LPCR, new_lpcr);
94 mtspr(SPRN_LPCR, old_lpcr);
100 static int stop_loop(struct cpuidle_device *dev,
101 struct cpuidle_driver *drv,
104 ppc64_runlatch_off();
105 power9_idle_stop(stop_psscr_table[index]);
111 * States for dedicated partition case.
113 static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = {
118 .target_residency = 0,
119 .enter = snooze_loop },
122 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
123 unsigned long action, void *hcpu)
125 int hotcpu = (unsigned long)hcpu;
126 struct cpuidle_device *dev =
127 per_cpu(cpuidle_devices, hotcpu);
129 if (dev && cpuidle_get_driver()) {
132 case CPU_ONLINE_FROZEN:
133 cpuidle_pause_and_lock();
134 cpuidle_enable_device(dev);
135 cpuidle_resume_and_unlock();
139 case CPU_DEAD_FROZEN:
140 cpuidle_pause_and_lock();
141 cpuidle_disable_device(dev);
142 cpuidle_resume_and_unlock();
152 static struct notifier_block setup_hotplug_notifier = {
153 .notifier_call = powernv_cpuidle_add_cpu_notifier,
157 * powernv_cpuidle_driver_init()
159 static int powernv_cpuidle_driver_init(void)
162 struct cpuidle_driver *drv = &powernv_idle_driver;
164 drv->state_count = 0;
166 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
167 /* Is the state not enabled? */
168 if (cpuidle_state_table[idle_state].enter == NULL)
171 drv->states[drv->state_count] = /* structure copy */
172 cpuidle_state_table[idle_state];
174 drv->state_count += 1;
180 static int powernv_add_idle_states(void)
182 struct device_node *power_mgt;
183 int nr_idle_states = 1; /* Snooze */
185 u32 latency_ns[CPUIDLE_STATE_MAX];
186 u32 residency_ns[CPUIDLE_STATE_MAX];
187 u32 flags[CPUIDLE_STATE_MAX];
188 u64 psscr_val[CPUIDLE_STATE_MAX];
189 const char *names[CPUIDLE_STATE_MAX];
192 /* Currently we have snooze statically defined */
194 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
196 pr_warn("opal: PowerMgmt Node not found\n");
200 /* Read values of any property to determine the num of idle states */
201 dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
202 if (dt_idle_states < 0) {
203 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
208 * Since snooze is used as first idle state, max idle states allowed is
209 * CPUIDLE_STATE_MAX -1
211 if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
212 pr_warn("cpuidle-powernv: discovered idle states more than allowed");
213 dt_idle_states = CPUIDLE_STATE_MAX - 1;
216 if (of_property_read_u32_array(power_mgt,
217 "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
218 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
222 if (of_property_read_u32_array(power_mgt,
223 "ibm,cpu-idle-state-latencies-ns", latency_ns,
225 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
228 if (of_property_read_string_array(power_mgt,
229 "ibm,cpu-idle-state-names", names, dt_idle_states) < 0) {
230 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
235 * If the idle states use stop instruction, probe for psscr values
236 * which are necessary to specify required stop level.
238 if (flags[0] & (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP))
239 if (of_property_read_u64_array(power_mgt,
240 "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) {
241 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n");
245 rc = of_property_read_u32_array(power_mgt,
246 "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
248 for (i = 0; i < dt_idle_states; i++) {
250 * If an idle state has exit latency beyond
251 * POWERNV_THRESHOLD_LATENCY_NS then don't use it
254 if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
258 * Cpuidle accepts exit_latency and target_residency in us.
259 * Use default target_residency values if f/w does not expose it.
261 if (flags[i] & OPAL_PM_NAP_ENABLED) {
263 strcpy(powernv_states[nr_idle_states].name, "Nap");
264 strcpy(powernv_states[nr_idle_states].desc, "Nap");
265 powernv_states[nr_idle_states].flags = 0;
266 powernv_states[nr_idle_states].target_residency = 100;
267 powernv_states[nr_idle_states].enter = nap_loop;
268 } else if ((flags[i] & OPAL_PM_STOP_INST_FAST) &&
269 !(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
270 strncpy(powernv_states[nr_idle_states].name,
271 names[i], CPUIDLE_NAME_LEN);
272 strncpy(powernv_states[nr_idle_states].desc,
273 names[i], CPUIDLE_NAME_LEN);
274 powernv_states[nr_idle_states].flags = 0;
276 powernv_states[nr_idle_states].enter = stop_loop;
277 stop_psscr_table[nr_idle_states] = psscr_val[i];
281 * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
282 * within this config dependency check.
284 #ifdef CONFIG_TICK_ONESHOT
285 if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
286 flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
287 /* Add FASTSLEEP state */
288 strcpy(powernv_states[nr_idle_states].name, "FastSleep");
289 strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
290 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
291 powernv_states[nr_idle_states].target_residency = 300000;
292 powernv_states[nr_idle_states].enter = fastsleep_loop;
293 } else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) &&
294 (flags[i] & OPAL_PM_TIMEBASE_STOP)) {
295 strncpy(powernv_states[nr_idle_states].name,
296 names[i], CPUIDLE_NAME_LEN);
297 strncpy(powernv_states[nr_idle_states].desc,
298 names[i], CPUIDLE_NAME_LEN);
300 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
301 powernv_states[nr_idle_states].enter = stop_loop;
302 stop_psscr_table[nr_idle_states] = psscr_val[i];
305 powernv_states[nr_idle_states].exit_latency =
306 ((unsigned int)latency_ns[i]) / 1000;
309 powernv_states[nr_idle_states].target_residency =
310 ((unsigned int)residency_ns[i]) / 1000;
316 return nr_idle_states;
320 * powernv_idle_probe()
321 * Choose state table for shared versus dedicated partition
323 static int powernv_idle_probe(void)
325 if (cpuidle_disable != IDLE_NO_OVERRIDE)
328 if (firmware_has_feature(FW_FEATURE_OPAL)) {
329 cpuidle_state_table = powernv_states;
330 /* Device tree can indicate more idle states */
331 max_idle_state = powernv_add_idle_states();
332 if (max_idle_state > 1) {
333 snooze_timeout_en = true;
334 snooze_timeout = powernv_states[1].target_residency *
343 static int __init powernv_processor_idle_init(void)
347 retval = powernv_idle_probe();
351 powernv_cpuidle_driver_init();
352 retval = cpuidle_register(&powernv_idle_driver, NULL);
354 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
358 register_cpu_notifier(&setup_hotplug_notifier);
359 printk(KERN_DEBUG "powernv_idle_driver registered\n");
363 device_initcall(powernv_processor_idle_init);