2 * POWERNV cpufreq driver for the IBM POWER processors
4 * (C) Copyright IBM 2014
6 * Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2, or (at your option)
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
20 #define pr_fmt(fmt) "powernv-cpufreq: " fmt
22 #include <linux/kernel.h>
23 #include <linux/sysfs.h>
24 #include <linux/cpumask.h>
25 #include <linux/module.h>
26 #include <linux/cpufreq.h>
27 #include <linux/smp.h>
29 #include <linux/reboot.h>
30 #include <linux/slab.h>
31 #include <linux/cpu.h>
32 #include <trace/events/power.h>
34 #include <asm/cputhreads.h>
35 #include <asm/firmware.h>
37 #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
39 #include <linux/timer.h>
41 #define POWERNV_MAX_PSTATES 256
42 #define PMSR_PSAFE_ENABLE (1UL << 30)
43 #define PMSR_SPR_EM_DISABLE (1UL << 31)
44 #define PMSR_MAX(x) ((x >> 32) & 0xFF)
46 #define MAX_RAMP_DOWN_TIME 5120
48 * On an idle system we want the global pstate to ramp-down from max value to
49 * min over a span of ~5 secs. Also we want it to initially ramp-down slowly and
50 * then ramp-down rapidly later on.
52 * This gives a percentage rampdown for time elapsed in milliseconds.
53 * ramp_down_percentage = ((ms * ms) >> 18)
54 * ~= 3.8 * (sec * sec)
56 * At 0 ms ramp_down_percent = 0
57 * At 5120 ms ramp_down_percent = 100
59 #define ramp_down_percent(time) ((time * time) >> 18)
61 /* Interval after which the timer is queued to bring down global pstate */
62 #define GPSTATE_TIMER_INTERVAL 2000
65 * struct global_pstate_info - Per policy data structure to maintain history of
67 * @highest_lpstate_idx: The local pstate index from which we are
69 * @elapsed_time: Time in ms spent in ramping down from
71 * @last_sampled_time: Time from boot in ms when global pstates were
73 * @last_lpstate_idx, Last set value of local pstate and global
74 * last_gpstate_idx pstate in terms of cpufreq table index
75 * @timer: Is used for ramping down if cpu goes idle for
76 * a long time with global pstate held high
77 * @gpstate_lock: A spinlock to maintain synchronization between
78 * routines called by the timer handler and
79 * governer's target_index calls
81 struct global_pstate_info {
82 int highest_lpstate_idx;
83 unsigned int elapsed_time;
84 unsigned int last_sampled_time;
87 spinlock_t gpstate_lock;
88 struct timer_list timer;
91 static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
92 static bool rebooting, throttled, occ_reset;
94 static const char * const throttle_reason[] = {
97 "Processor Over Temperature",
98 "Power Supply Failure",
103 enum throttle_reason_type {
107 POWER_SUPPLY_FAILURE,
119 struct work_struct throttle;
121 int throttle_sub_turbo;
122 int reason[OCC_MAX_REASON];
126 static DEFINE_PER_CPU(struct chip *, chip_info);
130 * The set of pstates consists of contiguous integers.
131 * powernv_pstate_info stores the index of the frequency table for
132 * max, min and nominal frequencies. It also stores number of
133 * available frequencies.
135 * powernv_pstate_info.nominal indicates the index to the highest
136 * non-turbo frequency.
138 static struct powernv_pstate_info {
141 unsigned int nominal;
142 unsigned int nr_pstates;
143 } powernv_pstate_info;
145 /* Use following macros for conversions between pstate_id and index */
146 static inline int idx_to_pstate(unsigned int i)
148 return powernv_freqs[i].driver_data;
151 static inline unsigned int pstate_to_idx(int pstate)
154 * abs() is deliberately used so that is works with
155 * both monotonically increasing and decreasing
158 return abs(pstate - idx_to_pstate(powernv_pstate_info.max));
161 static inline void reset_gpstates(struct cpufreq_policy *policy)
163 struct global_pstate_info *gpstates = policy->driver_data;
165 gpstates->highest_lpstate_idx = 0;
166 gpstates->elapsed_time = 0;
167 gpstates->last_sampled_time = 0;
168 gpstates->last_lpstate_idx = 0;
169 gpstates->last_gpstate_idx = 0;
173 * Initialize the freq table based on data obtained
174 * from the firmware passed via device-tree
176 static int init_powernv_pstates(void)
178 struct device_node *power_mgt;
179 int i, nr_pstates = 0;
180 const __be32 *pstate_ids, *pstate_freqs;
181 u32 len_ids, len_freqs;
182 u32 pstate_min, pstate_max, pstate_nominal;
184 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
186 pr_warn("power-mgt node not found\n");
190 if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
191 pr_warn("ibm,pstate-min node not found\n");
195 if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
196 pr_warn("ibm,pstate-max node not found\n");
200 if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
202 pr_warn("ibm,pstate-nominal not found\n");
205 pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min,
206 pstate_nominal, pstate_max);
208 pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
210 pr_warn("ibm,pstate-ids not found\n");
214 pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
217 pr_warn("ibm,pstate-frequencies-mhz not found\n");
221 if (len_ids != len_freqs) {
222 pr_warn("Entries in ibm,pstate-ids and "
223 "ibm,pstate-frequencies-mhz does not match\n");
226 nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
228 pr_warn("No PStates found\n");
232 powernv_pstate_info.nr_pstates = nr_pstates;
233 pr_debug("NR PStates %d\n", nr_pstates);
234 for (i = 0; i < nr_pstates; i++) {
235 u32 id = be32_to_cpu(pstate_ids[i]);
236 u32 freq = be32_to_cpu(pstate_freqs[i]);
238 pr_debug("PState id %d freq %d MHz\n", id, freq);
239 powernv_freqs[i].frequency = freq * 1000; /* kHz */
240 powernv_freqs[i].driver_data = id;
242 if (id == pstate_max)
243 powernv_pstate_info.max = i;
244 else if (id == pstate_nominal)
245 powernv_pstate_info.nominal = i;
246 else if (id == pstate_min)
247 powernv_pstate_info.min = i;
250 /* End of list marker entry */
251 powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
255 /* Returns the CPU frequency corresponding to the pstate_id. */
256 static unsigned int pstate_id_to_freq(int pstate_id)
260 i = pstate_to_idx(pstate_id);
261 if (i >= powernv_pstate_info.nr_pstates || i < 0) {
262 pr_warn("PState id %d outside of PState table, "
263 "reporting nominal id %d instead\n",
264 pstate_id, idx_to_pstate(powernv_pstate_info.nominal));
265 i = powernv_pstate_info.nominal;
268 return powernv_freqs[i].frequency;
272 * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
275 static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
278 return sprintf(buf, "%u\n",
279 powernv_freqs[powernv_pstate_info.nominal].frequency);
282 struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
283 __ATTR_RO(cpuinfo_nominal_freq);
285 static struct freq_attr *powernv_cpu_freq_attr[] = {
286 &cpufreq_freq_attr_scaling_available_freqs,
287 &cpufreq_freq_attr_cpuinfo_nominal_freq,
291 #define throttle_attr(name, member) \
292 static ssize_t name##_show(struct cpufreq_policy *policy, char *buf) \
294 struct chip *chip = per_cpu(chip_info, policy->cpu); \
296 return sprintf(buf, "%u\n", chip->member); \
299 static struct freq_attr throttle_attr_##name = __ATTR_RO(name) \
301 throttle_attr(unthrottle, reason[NO_THROTTLE]);
302 throttle_attr(powercap, reason[POWERCAP]);
303 throttle_attr(overtemp, reason[CPU_OVERTEMP]);
304 throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
305 throttle_attr(overcurrent, reason[OVERCURRENT]);
306 throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
307 throttle_attr(turbo_stat, throttle_turbo);
308 throttle_attr(sub_turbo_stat, throttle_sub_turbo);
310 static struct attribute *throttle_attrs[] = {
311 &throttle_attr_unthrottle.attr,
312 &throttle_attr_powercap.attr,
313 &throttle_attr_overtemp.attr,
314 &throttle_attr_supply_fault.attr,
315 &throttle_attr_overcurrent.attr,
316 &throttle_attr_occ_reset.attr,
317 &throttle_attr_turbo_stat.attr,
318 &throttle_attr_sub_turbo_stat.attr,
322 static const struct attribute_group throttle_attr_grp = {
323 .name = "throttle_stats",
324 .attrs = throttle_attrs,
327 /* Helper routines */
329 /* Access helpers to power mgt SPR */
331 static inline unsigned long get_pmspr(unsigned long sprn)
335 return mfspr(SPRN_PMCR);
338 return mfspr(SPRN_PMICR);
341 return mfspr(SPRN_PMSR);
346 static inline void set_pmspr(unsigned long sprn, unsigned long val)
350 mtspr(SPRN_PMCR, val);
354 mtspr(SPRN_PMICR, val);
361 * Use objects of this type to query/update
362 * pstates on a remote CPU via smp_call_function.
364 struct powernv_smp_call_data {
371 * powernv_read_cpu_freq: Reads the current frequency on this CPU.
373 * Called via smp_call_function.
375 * Note: The caller of the smp_call_function should pass an argument of
376 * the type 'struct powernv_smp_call_data *' along with this function.
378 * The current frequency on this CPU will be returned via
379 * ((struct powernv_smp_call_data *)arg)->freq;
381 static void powernv_read_cpu_freq(void *arg)
383 unsigned long pmspr_val;
385 struct powernv_smp_call_data *freq_data = arg;
387 pmspr_val = get_pmspr(SPRN_PMSR);
390 * The local pstate id corresponds bits 48..55 in the PMSR.
391 * Note: Watch out for the sign!
393 local_pstate_id = (pmspr_val >> 48) & 0xFF;
394 freq_data->pstate_id = local_pstate_id;
395 freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
397 pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n",
398 raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
403 * powernv_cpufreq_get: Returns the CPU frequency as reported by the
404 * firmware for CPU 'cpu'. This value is reported through the sysfs
405 * file cpuinfo_cur_freq.
407 static unsigned int powernv_cpufreq_get(unsigned int cpu)
409 struct powernv_smp_call_data freq_data;
411 smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
414 return freq_data.freq;
418 * set_pstate: Sets the pstate on this CPU.
420 * This is called via an smp_call_function.
422 * The caller must ensure that freq_data is of the type
423 * (struct powernv_smp_call_data *) and the pstate_id which needs to be set
424 * on this CPU should be present in freq_data->pstate_id.
426 static void set_pstate(void *data)
429 struct powernv_smp_call_data *freq_data = data;
430 unsigned long pstate_ul = freq_data->pstate_id;
431 unsigned long gpstate_ul = freq_data->gpstate_id;
433 val = get_pmspr(SPRN_PMCR);
434 val = val & 0x0000FFFFFFFFFFFFULL;
436 pstate_ul = pstate_ul & 0xFF;
437 gpstate_ul = gpstate_ul & 0xFF;
439 /* Set both global(bits 56..63) and local(bits 48..55) PStates */
440 val = val | (gpstate_ul << 56) | (pstate_ul << 48);
442 pr_debug("Setting cpu %d pmcr to %016lX\n",
443 raw_smp_processor_id(), val);
444 set_pmspr(SPRN_PMCR, val);
448 * get_nominal_index: Returns the index corresponding to the nominal
449 * pstate in the cpufreq table
451 static inline unsigned int get_nominal_index(void)
453 return powernv_pstate_info.nominal;
456 static void powernv_cpufreq_throttle_check(void *data)
459 unsigned int cpu = smp_processor_id();
462 unsigned int pmsr_pmax_idx;
464 pmsr = get_pmspr(SPRN_PMSR);
465 chip = this_cpu_read(chip_info);
467 /* Check for Pmax Capping */
468 pmsr_pmax = (s8)PMSR_MAX(pmsr);
469 pmsr_pmax_idx = pstate_to_idx(pmsr_pmax);
470 if (pmsr_pmax_idx != powernv_pstate_info.max) {
473 chip->throttled = true;
474 if (pmsr_pmax_idx > powernv_pstate_info.nominal) {
475 pr_warn_once("CPU %d on Chip %u has Pmax(%d) reduced below nominal frequency(%d)\n",
476 cpu, chip->id, pmsr_pmax,
477 idx_to_pstate(powernv_pstate_info.nominal));
478 chip->throttle_sub_turbo++;
480 chip->throttle_turbo++;
482 trace_powernv_throttle(chip->id,
483 throttle_reason[chip->throttle_reason],
485 } else if (chip->throttled) {
486 chip->throttled = false;
487 trace_powernv_throttle(chip->id,
488 throttle_reason[chip->throttle_reason],
492 /* Check if Psafe_mode_active is set in PMSR. */
494 if (pmsr & PMSR_PSAFE_ENABLE) {
496 pr_info("Pstate set to safe frequency\n");
499 /* Check if SPR_EM_DISABLE is set in PMSR */
500 if (pmsr & PMSR_SPR_EM_DISABLE) {
502 pr_info("Frequency Control disabled from OS\n");
506 pr_info("PMSR = %16lx\n", pmsr);
507 pr_warn("CPU Frequency could be throttled\n");
512 * calc_global_pstate - Calculate global pstate
513 * @elapsed_time: Elapsed time in milliseconds
514 * @local_pstate_idx: New local pstate
515 * @highest_lpstate_idx: pstate from which its ramping down
517 * Finds the appropriate global pstate based on the pstate from which its
518 * ramping down and the time elapsed in ramping down. It follows a quadratic
519 * equation which ensures that it reaches ramping down to pmin in 5sec.
521 static inline int calc_global_pstate(unsigned int elapsed_time,
522 int highest_lpstate_idx,
523 int local_pstate_idx)
528 * Using ramp_down_percent we get the percentage of rampdown
529 * that we are expecting to be dropping. Difference between
530 * highest_lpstate_idx and powernv_pstate_info.min will give a absolute
531 * number of how many pstates we will drop eventually by the end of
532 * 5 seconds, then just scale it get the number pstates to be dropped.
534 index_diff = ((int)ramp_down_percent(elapsed_time) *
535 (powernv_pstate_info.min - highest_lpstate_idx)) / 100;
537 /* Ensure that global pstate is >= to local pstate */
538 if (highest_lpstate_idx + index_diff >= local_pstate_idx)
539 return local_pstate_idx;
541 return highest_lpstate_idx + index_diff;
544 static inline void queue_gpstate_timer(struct global_pstate_info *gpstates)
546 unsigned int timer_interval;
549 * Setting up timer to fire after GPSTATE_TIMER_INTERVAL ms, But
550 * if it exceeds MAX_RAMP_DOWN_TIME ms for ramp down time.
551 * Set timer such that it fires exactly at MAX_RAMP_DOWN_TIME
552 * seconds of ramp down time.
554 if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL)
555 > MAX_RAMP_DOWN_TIME)
556 timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time;
558 timer_interval = GPSTATE_TIMER_INTERVAL;
560 mod_timer_pinned(&gpstates->timer, jiffies +
561 msecs_to_jiffies(timer_interval));
565 * gpstate_timer_handler
567 * @data: pointer to cpufreq_policy on which timer was queued
569 * This handler brings down the global pstate closer to the local pstate
570 * according quadratic equation. Queues a new timer if it is still not equal
573 void gpstate_timer_handler(unsigned long data)
575 struct cpufreq_policy *policy = (struct cpufreq_policy *)data;
576 struct global_pstate_info *gpstates = policy->driver_data;
578 unsigned int time_diff = jiffies_to_msecs(jiffies)
579 - gpstates->last_sampled_time;
580 struct powernv_smp_call_data freq_data;
582 if (!spin_trylock(&gpstates->gpstate_lock))
585 gpstates->last_sampled_time += time_diff;
586 gpstates->elapsed_time += time_diff;
587 freq_data.pstate_id = idx_to_pstate(gpstates->last_lpstate_idx);
589 if ((gpstates->last_gpstate_idx == gpstates->last_lpstate_idx) ||
590 (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME)) {
591 gpstate_idx = pstate_to_idx(freq_data.pstate_id);
592 reset_gpstates(policy);
593 gpstates->highest_lpstate_idx = gpstate_idx;
595 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
596 gpstates->highest_lpstate_idx,
597 freq_data.pstate_id);
601 * If local pstate is equal to global pstate, rampdown is over
602 * So timer is not required to be queued.
604 if (gpstate_idx != gpstates->last_lpstate_idx)
605 queue_gpstate_timer(gpstates);
607 freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
608 gpstates->last_gpstate_idx = pstate_to_idx(freq_data.gpstate_id);
609 gpstates->last_lpstate_idx = pstate_to_idx(freq_data.pstate_id);
611 spin_unlock(&gpstates->gpstate_lock);
613 /* Timer may get migrated to a different cpu on cpu hot unplug */
614 smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
618 * powernv_cpufreq_target_index: Sets the frequency corresponding to
619 * the cpufreq table entry indexed by new_index on the cpus in the
622 static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
623 unsigned int new_index)
625 struct powernv_smp_call_data freq_data;
626 unsigned int cur_msec, gpstate_idx;
627 struct global_pstate_info *gpstates = policy->driver_data;
629 if (unlikely(rebooting) && new_index != get_nominal_index())
633 powernv_cpufreq_throttle_check(NULL);
635 cur_msec = jiffies_to_msecs(get_jiffies_64());
637 spin_lock(&gpstates->gpstate_lock);
638 freq_data.pstate_id = idx_to_pstate(new_index);
640 if (!gpstates->last_sampled_time) {
641 gpstate_idx = new_index;
642 gpstates->highest_lpstate_idx = new_index;
646 if (gpstates->last_gpstate_idx < new_index) {
647 gpstates->elapsed_time += cur_msec -
648 gpstates->last_sampled_time;
651 * If its has been ramping down for more than MAX_RAMP_DOWN_TIME
652 * we should be resetting all global pstate related data. Set it
653 * equal to local pstate to start fresh.
655 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
656 reset_gpstates(policy);
657 gpstates->highest_lpstate_idx = new_index;
658 gpstate_idx = new_index;
660 /* Elaspsed_time is less than 5 seconds, continue to rampdown */
661 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
662 gpstates->highest_lpstate_idx,
666 reset_gpstates(policy);
667 gpstates->highest_lpstate_idx = new_index;
668 gpstate_idx = new_index;
672 * If local pstate is equal to global pstate, rampdown is over
673 * So timer is not required to be queued.
675 if (gpstate_idx != new_index)
676 queue_gpstate_timer(gpstates);
678 del_timer_sync(&gpstates->timer);
681 freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
682 gpstates->last_sampled_time = cur_msec;
683 gpstates->last_gpstate_idx = gpstate_idx;
684 gpstates->last_lpstate_idx = new_index;
686 spin_unlock(&gpstates->gpstate_lock);
689 * Use smp_call_function to send IPI and execute the
690 * mtspr on target CPU. We could do that without IPI
691 * if current CPU is within policy->cpus (core)
693 smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
697 static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
700 struct kernfs_node *kn;
701 struct global_pstate_info *gpstates;
703 base = cpu_first_thread_sibling(policy->cpu);
705 for (i = 0; i < threads_per_core; i++)
706 cpumask_set_cpu(base + i, policy->cpus);
708 kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
712 ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
714 pr_info("Failed to create throttle stats directory for cpu %d\n",
722 gpstates = kzalloc(sizeof(*gpstates), GFP_KERNEL);
726 policy->driver_data = gpstates;
728 /* initialize timer */
729 init_timer_deferrable(&gpstates->timer);
730 gpstates->timer.data = (unsigned long)policy;
731 gpstates->timer.function = gpstate_timer_handler;
732 gpstates->timer.expires = jiffies +
733 msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
734 spin_lock_init(&gpstates->gpstate_lock);
735 ret = cpufreq_table_validate_and_show(policy, powernv_freqs);
738 kfree(policy->driver_data);
743 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
745 /* timer is deleted in cpufreq_cpu_stop() */
746 kfree(policy->driver_data);
751 static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
752 unsigned long action, void *unused)
755 struct cpufreq_policy cpu_policy;
758 for_each_online_cpu(cpu) {
759 cpufreq_get_policy(&cpu_policy, cpu);
760 powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
766 static struct notifier_block powernv_cpufreq_reboot_nb = {
767 .notifier_call = powernv_cpufreq_reboot_notifier,
770 void powernv_cpufreq_work_fn(struct work_struct *work)
772 struct chip *chip = container_of(work, struct chip, throttle);
777 cpumask_and(&mask, &chip->mask, cpu_online_mask);
778 smp_call_function_any(&mask,
779 powernv_cpufreq_throttle_check, NULL, 0);
784 chip->restore = false;
785 for_each_cpu(cpu, &mask) {
787 struct cpufreq_policy policy;
789 cpufreq_get_policy(&policy, cpu);
790 index = cpufreq_table_find_index_c(&policy, policy.cur);
791 powernv_cpufreq_target_index(&policy, index);
792 cpumask_andnot(&mask, &mask, policy.cpus);
798 static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
799 unsigned long msg_type, void *_msg)
801 struct opal_msg *msg = _msg;
802 struct opal_occ_msg omsg;
805 if (msg_type != OPAL_MSG_OCC)
808 omsg.type = be64_to_cpu(msg->params[0]);
813 pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
815 * powernv_cpufreq_throttle_check() is called in
816 * target() callback which can detect the throttle state
817 * for governors like ondemand.
818 * But static governors will not call target() often thus
819 * report throttling here.
823 pr_warn("CPU frequency is throttled for duration\n");
828 pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
831 omsg.chip = be64_to_cpu(msg->params[1]);
832 omsg.throttle_status = be64_to_cpu(msg->params[2]);
837 pr_info("OCC Active, CPU frequency is no longer throttled\n");
839 for (i = 0; i < nr_chips; i++) {
840 chips[i].restore = true;
841 schedule_work(&chips[i].throttle);
847 for (i = 0; i < nr_chips; i++)
848 if (chips[i].id == omsg.chip)
851 if (omsg.throttle_status >= 0 &&
852 omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
853 chips[i].throttle_reason = omsg.throttle_status;
854 chips[i].reason[omsg.throttle_status]++;
857 if (!omsg.throttle_status)
858 chips[i].restore = true;
860 schedule_work(&chips[i].throttle);
865 static struct notifier_block powernv_cpufreq_opal_nb = {
866 .notifier_call = powernv_cpufreq_occ_msg,
871 static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
873 struct powernv_smp_call_data freq_data;
874 struct global_pstate_info *gpstates = policy->driver_data;
876 freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
877 freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
878 smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
879 del_timer_sync(&gpstates->timer);
882 static struct cpufreq_driver powernv_cpufreq_driver = {
883 .name = "powernv-cpufreq",
884 .flags = CPUFREQ_CONST_LOOPS,
885 .init = powernv_cpufreq_cpu_init,
886 .exit = powernv_cpufreq_cpu_exit,
887 .verify = cpufreq_generic_frequency_table_verify,
888 .target_index = powernv_cpufreq_target_index,
889 .get = powernv_cpufreq_get,
890 .stop_cpu = powernv_cpufreq_stop_cpu,
891 .attr = powernv_cpu_freq_attr,
894 static int init_chip_info(void)
896 unsigned int chip[256];
898 unsigned int prev_chip_id = UINT_MAX;
900 for_each_possible_cpu(cpu) {
901 unsigned int id = cpu_to_chip_id(cpu);
903 if (prev_chip_id != id) {
905 chip[nr_chips++] = id;
909 chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
913 for (i = 0; i < nr_chips; i++) {
914 chips[i].id = chip[i];
915 cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
916 INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
917 for_each_cpu(cpu, &chips[i].mask)
918 per_cpu(chip_info, cpu) = &chips[i];
924 static inline void clean_chip_info(void)
929 static inline void unregister_all_notifiers(void)
931 opal_message_notifier_unregister(OPAL_MSG_OCC,
932 &powernv_cpufreq_opal_nb);
933 unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
936 static int __init powernv_cpufreq_init(void)
940 /* Don't probe on pseries (guest) platforms */
941 if (!firmware_has_feature(FW_FEATURE_OPAL))
944 /* Discover pstates from device tree and init */
945 rc = init_powernv_pstates();
949 /* Populate chip info */
950 rc = init_chip_info();
954 register_reboot_notifier(&powernv_cpufreq_reboot_nb);
955 opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
957 rc = cpufreq_register_driver(&powernv_cpufreq_driver);
961 pr_info("Failed to register the cpufreq driver (%d)\n", rc);
962 unregister_all_notifiers();
965 pr_info("Platform driver disabled. System does not support PState control\n");
968 module_init(powernv_cpufreq_init);
970 static void __exit powernv_cpufreq_exit(void)
972 cpufreq_unregister_driver(&powernv_cpufreq_driver);
973 unregister_all_notifiers();
976 module_exit(powernv_cpufreq_exit);
978 MODULE_LICENSE("GPL");
979 MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");