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>
22 #include <asm/cpuidle.h>
25 * Expose only those Hardware idle states via the cpuidle framework
26 * that have latency value below POWERNV_THRESHOLD_LATENCY_NS.
28 #define POWERNV_THRESHOLD_LATENCY_NS 200000
30 static struct cpuidle_driver powernv_idle_driver = {
31 .name = "powernv_idle",
35 static int max_idle_state __read_mostly;
36 static struct cpuidle_state *cpuidle_state_table __read_mostly;
38 struct stop_psscr_table {
43 static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly;
45 static u64 snooze_timeout __read_mostly;
46 static bool snooze_timeout_en __read_mostly;
48 static int snooze_loop(struct cpuidle_device *dev,
49 struct cpuidle_driver *drv,
54 set_thread_flag(TIF_POLLING_NRFLAG);
58 snooze_exit_time = get_tb() + snooze_timeout;
61 while (!need_resched()) {
62 if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) {
64 * Task has not woken up but we are exiting the polling
65 * loop anyway. Require a barrier after polling is
66 * cleared to order subsequent test of need_resched().
68 clear_thread_flag(TIF_POLLING_NRFLAG);
76 clear_thread_flag(TIF_POLLING_NRFLAG);
81 static int nap_loop(struct cpuidle_device *dev,
82 struct cpuidle_driver *drv,
85 power7_idle_type(PNV_THREAD_NAP);
90 /* Register for fastsleep only in oneshot mode of broadcast */
91 #ifdef CONFIG_TICK_ONESHOT
92 static int fastsleep_loop(struct cpuidle_device *dev,
93 struct cpuidle_driver *drv,
96 unsigned long old_lpcr = mfspr(SPRN_LPCR);
97 unsigned long new_lpcr;
99 if (unlikely(system_state < SYSTEM_RUNNING))
103 /* Do not exit powersave upon decrementer as we've setup the timer
106 new_lpcr &= ~LPCR_PECE1;
108 mtspr(SPRN_LPCR, new_lpcr);
110 power7_idle_type(PNV_THREAD_SLEEP);
112 mtspr(SPRN_LPCR, old_lpcr);
118 static int stop_loop(struct cpuidle_device *dev,
119 struct cpuidle_driver *drv,
122 power9_idle_type(stop_psscr_table[index].val,
123 stop_psscr_table[index].mask);
128 * States for dedicated partition case.
130 static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = {
135 .target_residency = 0,
136 .enter = snooze_loop },
139 static int powernv_cpuidle_cpu_online(unsigned int cpu)
141 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
143 if (dev && cpuidle_get_driver()) {
144 cpuidle_pause_and_lock();
145 cpuidle_enable_device(dev);
146 cpuidle_resume_and_unlock();
151 static int powernv_cpuidle_cpu_dead(unsigned int cpu)
153 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
155 if (dev && cpuidle_get_driver()) {
156 cpuidle_pause_and_lock();
157 cpuidle_disable_device(dev);
158 cpuidle_resume_and_unlock();
164 * powernv_cpuidle_driver_init()
166 static int powernv_cpuidle_driver_init(void)
169 struct cpuidle_driver *drv = &powernv_idle_driver;
171 drv->state_count = 0;
173 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
174 /* Is the state not enabled? */
175 if (cpuidle_state_table[idle_state].enter == NULL)
178 drv->states[drv->state_count] = /* structure copy */
179 cpuidle_state_table[idle_state];
181 drv->state_count += 1;
185 * On the PowerNV platform cpu_present may be less than cpu_possible in
186 * cases when firmware detects the CPU, but it is not available to the
187 * OS. If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at
188 * run time and hence cpu_devices are not created for those CPUs by the
189 * generic topology_init().
191 * drv->cpumask defaults to cpu_possible_mask in
192 * __cpuidle_driver_init(). This breaks cpuidle on PowerNV where
193 * cpu_devices are not created for CPUs in cpu_possible_mask that
194 * cannot be hot-added later at run time.
196 * Trying cpuidle_register_device() on a CPU without a cpu_device is
197 * incorrect, so pass a correct CPU mask to the generic cpuidle driver.
200 drv->cpumask = (struct cpumask *)cpu_present_mask;
205 static inline void add_powernv_state(int index, const char *name,
207 int (*idle_fn)(struct cpuidle_device *,
208 struct cpuidle_driver *,
210 unsigned int target_residency,
211 unsigned int exit_latency,
212 u64 psscr_val, u64 psscr_mask)
214 strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
215 strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
216 powernv_states[index].flags = flags;
217 powernv_states[index].target_residency = target_residency;
218 powernv_states[index].exit_latency = exit_latency;
219 powernv_states[index].enter = idle_fn;
220 stop_psscr_table[index].val = psscr_val;
221 stop_psscr_table[index].mask = psscr_mask;
225 * Returns 0 if prop1_len == prop2_len. Else returns -1
227 static inline int validate_dt_prop_sizes(const char *prop1, int prop1_len,
228 const char *prop2, int prop2_len)
230 if (prop1_len == prop2_len)
233 pr_warn("cpuidle-powernv: array sizes don't match for %s and %s\n",
238 extern u32 pnv_get_supported_cpuidle_states(void);
239 static int powernv_add_idle_states(void)
241 struct device_node *power_mgt;
242 int nr_idle_states = 1; /* Snooze */
243 int dt_idle_states, count;
244 u32 latency_ns[CPUIDLE_STATE_MAX];
245 u32 residency_ns[CPUIDLE_STATE_MAX];
246 u32 flags[CPUIDLE_STATE_MAX];
247 u64 psscr_val[CPUIDLE_STATE_MAX];
248 u64 psscr_mask[CPUIDLE_STATE_MAX];
249 const char *names[CPUIDLE_STATE_MAX];
250 u32 has_stop_states = 0;
252 u32 supported_flags = pnv_get_supported_cpuidle_states();
255 /* Currently we have snooze statically defined */
257 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
259 pr_warn("opal: PowerMgmt Node not found\n");
263 /* Read values of any property to determine the num of idle states */
264 dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
265 if (dt_idle_states < 0) {
266 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
270 count = of_property_count_u32_elems(power_mgt,
271 "ibm,cpu-idle-state-latencies-ns");
273 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
274 "ibm,cpu-idle-state-latencies-ns",
278 count = of_property_count_strings(power_mgt,
279 "ibm,cpu-idle-state-names");
280 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
281 "ibm,cpu-idle-state-names",
286 * Since snooze is used as first idle state, max idle states allowed is
287 * CPUIDLE_STATE_MAX -1
289 if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
290 pr_warn("cpuidle-powernv: discovered idle states more than allowed");
291 dt_idle_states = CPUIDLE_STATE_MAX - 1;
294 if (of_property_read_u32_array(power_mgt,
295 "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
296 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
300 if (of_property_read_u32_array(power_mgt,
301 "ibm,cpu-idle-state-latencies-ns", latency_ns,
303 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
306 if (of_property_read_string_array(power_mgt,
307 "ibm,cpu-idle-state-names", names, dt_idle_states) < 0) {
308 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
313 * If the idle states use stop instruction, probe for psscr values
314 * and psscr mask which are necessary to specify required stop level.
316 has_stop_states = (flags[0] &
317 (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
318 if (has_stop_states) {
319 count = of_property_count_u64_elems(power_mgt,
320 "ibm,cpu-idle-state-psscr");
321 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
323 "ibm,cpu-idle-state-psscr",
327 count = of_property_count_u64_elems(power_mgt,
328 "ibm,cpu-idle-state-psscr-mask");
329 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
331 "ibm,cpu-idle-state-psscr-mask",
335 if (of_property_read_u64_array(power_mgt,
336 "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) {
337 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
341 if (of_property_read_u64_array(power_mgt,
342 "ibm,cpu-idle-state-psscr-mask",
343 psscr_mask, dt_idle_states)) {
344 pr_warn("cpuidle-powernv:Missing ibm,cpu-idle-state-psscr-mask in DT\n");
349 count = of_property_count_u32_elems(power_mgt,
350 "ibm,cpu-idle-state-residency-ns");
354 } else if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
356 "ibm,cpu-idle-state-residency-ns",
360 rc = of_property_read_u32_array(power_mgt,
361 "ibm,cpu-idle-state-residency-ns",
362 residency_ns, dt_idle_states);
365 for (i = 0; i < dt_idle_states; i++) {
366 unsigned int exit_latency, target_residency;
367 bool stops_timebase = false;
370 * Skip the platform idle state whose flag isn't in
371 * the supported_cpuidle_states flag mask.
373 if ((flags[i] & supported_flags) != flags[i])
376 * If an idle state has exit latency beyond
377 * POWERNV_THRESHOLD_LATENCY_NS then don't use it
380 if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
383 * Firmware passes residency and latency values in ns.
384 * cpuidle expects it in us.
386 exit_latency = latency_ns[i] / 1000;
388 target_residency = residency_ns[i] / 1000;
390 target_residency = 0;
392 if (has_stop_states) {
393 int err = validate_psscr_val_mask(&psscr_val[i],
397 report_invalid_psscr_val(psscr_val[i], err);
402 if (flags[i] & OPAL_PM_TIMEBASE_STOP)
403 stops_timebase = true;
406 * For nap and fastsleep, use default target_residency
407 * values if f/w does not expose it.
409 if (flags[i] & OPAL_PM_NAP_ENABLED) {
411 target_residency = 100;
413 add_powernv_state(nr_idle_states, "Nap",
414 CPUIDLE_FLAG_NONE, nap_loop,
415 target_residency, exit_latency, 0, 0);
416 } else if (has_stop_states && !stops_timebase) {
417 add_powernv_state(nr_idle_states, names[i],
418 CPUIDLE_FLAG_NONE, stop_loop,
419 target_residency, exit_latency,
420 psscr_val[i], psscr_mask[i]);
424 * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
425 * within this config dependency check.
427 #ifdef CONFIG_TICK_ONESHOT
428 else if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
429 flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
431 target_residency = 300000;
432 /* Add FASTSLEEP state */
433 add_powernv_state(nr_idle_states, "FastSleep",
434 CPUIDLE_FLAG_TIMER_STOP,
436 target_residency, exit_latency, 0, 0);
437 } else if (has_stop_states && stops_timebase) {
438 add_powernv_state(nr_idle_states, names[i],
439 CPUIDLE_FLAG_TIMER_STOP, stop_loop,
440 target_residency, exit_latency,
441 psscr_val[i], psscr_mask[i]);
449 return nr_idle_states;
453 * powernv_idle_probe()
454 * Choose state table for shared versus dedicated partition
456 static int powernv_idle_probe(void)
458 if (cpuidle_disable != IDLE_NO_OVERRIDE)
461 if (firmware_has_feature(FW_FEATURE_OPAL)) {
462 cpuidle_state_table = powernv_states;
463 /* Device tree can indicate more idle states */
464 max_idle_state = powernv_add_idle_states();
465 if (max_idle_state > 1) {
466 snooze_timeout_en = true;
467 snooze_timeout = powernv_states[1].target_residency *
476 static int __init powernv_processor_idle_init(void)
480 retval = powernv_idle_probe();
484 powernv_cpuidle_driver_init();
485 retval = cpuidle_register(&powernv_idle_driver, NULL);
487 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
491 retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
492 "cpuidle/powernv:online",
493 powernv_cpuidle_cpu_online, NULL);
495 retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD,
496 "cpuidle/powernv:dead", NULL,
497 powernv_cpuidle_cpu_dead);
499 printk(KERN_DEBUG "powernv_idle_driver registered\n");
503 device_initcall(powernv_processor_idle_init);