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 <linux/hashtable.h>
33 #include <trace/events/power.h>
35 #include <asm/cputhreads.h>
36 #include <asm/firmware.h>
38 #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
40 #include <linux/timer.h>
42 #define POWERNV_MAX_PSTATES_ORDER 8
43 #define POWERNV_MAX_PSTATES (1UL << (POWERNV_MAX_PSTATES_ORDER))
44 #define PMSR_PSAFE_ENABLE (1UL << 30)
45 #define PMSR_SPR_EM_DISABLE (1UL << 31)
46 #define MAX_PSTATE_SHIFT 32
47 #define LPSTATE_SHIFT 48
48 #define GPSTATE_SHIFT 56
50 #define MAX_RAMP_DOWN_TIME 5120
52 * On an idle system we want the global pstate to ramp-down from max value to
53 * min over a span of ~5 secs. Also we want it to initially ramp-down slowly and
54 * then ramp-down rapidly later on.
56 * This gives a percentage rampdown for time elapsed in milliseconds.
57 * ramp_down_percentage = ((ms * ms) >> 18)
58 * ~= 3.8 * (sec * sec)
60 * At 0 ms ramp_down_percent = 0
61 * At 5120 ms ramp_down_percent = 100
63 #define ramp_down_percent(time) ((time * time) >> 18)
65 /* Interval after which the timer is queued to bring down global pstate */
66 #define GPSTATE_TIMER_INTERVAL 2000
69 * struct global_pstate_info - Per policy data structure to maintain history of
71 * @highest_lpstate_idx: The local pstate index from which we are
73 * @elapsed_time: Time in ms spent in ramping down from
75 * @last_sampled_time: Time from boot in ms when global pstates were
77 * @last_lpstate_idx, Last set value of local pstate and global
78 * last_gpstate_idx pstate in terms of cpufreq table index
79 * @timer: Is used for ramping down if cpu goes idle for
80 * a long time with global pstate held high
81 * @gpstate_lock: A spinlock to maintain synchronization between
82 * routines called by the timer handler and
83 * governer's target_index calls
85 struct global_pstate_info {
86 int highest_lpstate_idx;
87 unsigned int elapsed_time;
88 unsigned int last_sampled_time;
91 spinlock_t gpstate_lock;
92 struct timer_list timer;
93 struct cpufreq_policy *policy;
96 static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
98 DEFINE_HASHTABLE(pstate_revmap, POWERNV_MAX_PSTATES_ORDER);
100 * struct pstate_idx_revmap_data: Entry in the hashmap pstate_revmap
101 * indexed by a function of pstate id.
103 * @pstate_id: pstate id for this entry.
105 * @cpufreq_table_idx: Index into the powernv_freqs
106 * cpufreq_frequency_table for frequency
107 * corresponding to pstate_id.
109 * @hentry: hlist_node that hooks this entry into the pstate_revmap
112 struct pstate_idx_revmap_data {
114 unsigned int cpufreq_table_idx;
115 struct hlist_node hentry;
118 u32 pstate_sign_prefix;
119 static bool rebooting, throttled, occ_reset;
121 static const char * const throttle_reason[] = {
124 "Processor Over Temperature",
125 "Power Supply Failure",
130 enum throttle_reason_type {
134 POWER_SUPPLY_FAILURE,
146 struct work_struct throttle;
148 int throttle_sub_turbo;
149 int reason[OCC_MAX_REASON];
153 static DEFINE_PER_CPU(struct chip *, chip_info);
157 * The set of pstates consists of contiguous integers.
158 * powernv_pstate_info stores the index of the frequency table for
159 * max, min and nominal frequencies. It also stores number of
160 * available frequencies.
162 * powernv_pstate_info.nominal indicates the index to the highest
163 * non-turbo frequency.
165 static struct powernv_pstate_info {
168 unsigned int nominal;
169 unsigned int nr_pstates;
171 } powernv_pstate_info;
173 static inline int extract_pstate(u64 pmsr_val, unsigned int shift)
175 int ret = ((pmsr_val >> shift) & 0xFF);
180 return (pstate_sign_prefix | ret);
183 #define extract_local_pstate(x) extract_pstate(x, LPSTATE_SHIFT)
184 #define extract_global_pstate(x) extract_pstate(x, GPSTATE_SHIFT)
185 #define extract_max_pstate(x) extract_pstate(x, MAX_PSTATE_SHIFT)
187 /* Use following functions for conversions between pstate_id and index */
190 * idx_to_pstate : Returns the pstate id corresponding to the
191 * frequency in the cpufreq frequency table
192 * powernv_freqs indexed by @i.
194 * If @i is out of bound, this will return the pstate
195 * corresponding to the nominal frequency.
197 static inline int idx_to_pstate(unsigned int i)
199 if (unlikely(i >= powernv_pstate_info.nr_pstates)) {
200 pr_warn_once("idx_to_pstate: index %u is out of bound\n", i);
201 return powernv_freqs[powernv_pstate_info.nominal].driver_data;
204 return powernv_freqs[i].driver_data;
208 * pstate_to_idx : Returns the index in the cpufreq frequencytable
209 * powernv_freqs for the frequency whose corresponding
210 * pstate id is @pstate.
212 * If no frequency corresponding to @pstate is found,
213 * this will return the index of the nominal
216 static unsigned int pstate_to_idx(int pstate)
218 unsigned int key = pstate % POWERNV_MAX_PSTATES;
219 struct pstate_idx_revmap_data *revmap_data;
221 hash_for_each_possible(pstate_revmap, revmap_data, hentry, key) {
222 if (revmap_data->pstate_id == pstate)
223 return revmap_data->cpufreq_table_idx;
226 pr_warn_once("pstate_to_idx: pstate %d not found\n", pstate);
227 return powernv_pstate_info.nominal;
230 static inline void reset_gpstates(struct cpufreq_policy *policy)
232 struct global_pstate_info *gpstates = policy->driver_data;
234 gpstates->highest_lpstate_idx = 0;
235 gpstates->elapsed_time = 0;
236 gpstates->last_sampled_time = 0;
237 gpstates->last_lpstate_idx = 0;
238 gpstates->last_gpstate_idx = 0;
242 * Initialize the freq table based on data obtained
243 * from the firmware passed via device-tree
245 static int init_powernv_pstates(void)
247 struct device_node *power_mgt;
248 int i, nr_pstates = 0;
249 const __be32 *pstate_ids, *pstate_freqs;
250 u32 len_ids, len_freqs;
251 u32 pstate_min, pstate_max, pstate_nominal;
252 u32 pstate_turbo, pstate_ultra_turbo;
254 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
256 pr_warn("power-mgt node not found\n");
260 if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
261 pr_warn("ibm,pstate-min node not found\n");
265 if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
266 pr_warn("ibm,pstate-max node not found\n");
270 if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
272 pr_warn("ibm,pstate-nominal not found\n");
276 if (of_property_read_u32(power_mgt, "ibm,pstate-ultra-turbo",
277 &pstate_ultra_turbo)) {
278 powernv_pstate_info.wof_enabled = false;
282 if (of_property_read_u32(power_mgt, "ibm,pstate-turbo",
284 powernv_pstate_info.wof_enabled = false;
288 if (pstate_turbo == pstate_ultra_turbo)
289 powernv_pstate_info.wof_enabled = false;
291 powernv_pstate_info.wof_enabled = true;
294 pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min,
295 pstate_nominal, pstate_max);
296 pr_info("Workload Optimized Frequency is %s in the platform\n",
297 (powernv_pstate_info.wof_enabled) ? "enabled" : "disabled");
299 pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
301 pr_warn("ibm,pstate-ids not found\n");
305 pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
308 pr_warn("ibm,pstate-frequencies-mhz not found\n");
312 if (len_ids != len_freqs) {
313 pr_warn("Entries in ibm,pstate-ids and "
314 "ibm,pstate-frequencies-mhz does not match\n");
317 nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
319 pr_warn("No PStates found\n");
323 powernv_pstate_info.nr_pstates = nr_pstates;
324 pr_debug("NR PStates %d\n", nr_pstates);
326 pstate_sign_prefix = pstate_min & ~0xFF;
328 for (i = 0; i < nr_pstates; i++) {
329 u32 id = be32_to_cpu(pstate_ids[i]);
330 u32 freq = be32_to_cpu(pstate_freqs[i]);
331 struct pstate_idx_revmap_data *revmap_data;
334 pr_debug("PState id %d freq %d MHz\n", id, freq);
335 powernv_freqs[i].frequency = freq * 1000; /* kHz */
336 powernv_freqs[i].driver_data = id;
338 revmap_data = (struct pstate_idx_revmap_data *)
339 kmalloc(sizeof(*revmap_data), GFP_KERNEL);
341 revmap_data->pstate_id = id;
342 revmap_data->cpufreq_table_idx = i;
343 key = id % POWERNV_MAX_PSTATES;
344 hash_add(pstate_revmap, &revmap_data->hentry, key);
346 if (id == pstate_max)
347 powernv_pstate_info.max = i;
348 else if (id == pstate_nominal)
349 powernv_pstate_info.nominal = i;
350 else if (id == pstate_min)
351 powernv_pstate_info.min = i;
353 if (powernv_pstate_info.wof_enabled && id == pstate_turbo) {
356 for (j = i - 1; j >= (int)powernv_pstate_info.max; j--)
357 powernv_freqs[j].flags = CPUFREQ_BOOST_FREQ;
361 /* End of list marker entry */
362 powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
366 /* Returns the CPU frequency corresponding to the pstate_id. */
367 static unsigned int pstate_id_to_freq(int pstate_id)
371 i = pstate_to_idx(pstate_id);
372 if (i >= powernv_pstate_info.nr_pstates || i < 0) {
373 pr_warn("PState id %d outside of PState table, "
374 "reporting nominal id %d instead\n",
375 pstate_id, idx_to_pstate(powernv_pstate_info.nominal));
376 i = powernv_pstate_info.nominal;
379 return powernv_freqs[i].frequency;
383 * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
386 static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
389 return sprintf(buf, "%u\n",
390 powernv_freqs[powernv_pstate_info.nominal].frequency);
393 struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
394 __ATTR_RO(cpuinfo_nominal_freq);
396 #define SCALING_BOOST_FREQS_ATTR_INDEX 2
398 static struct freq_attr *powernv_cpu_freq_attr[] = {
399 &cpufreq_freq_attr_scaling_available_freqs,
400 &cpufreq_freq_attr_cpuinfo_nominal_freq,
401 &cpufreq_freq_attr_scaling_boost_freqs,
405 #define throttle_attr(name, member) \
406 static ssize_t name##_show(struct cpufreq_policy *policy, char *buf) \
408 struct chip *chip = per_cpu(chip_info, policy->cpu); \
410 return sprintf(buf, "%u\n", chip->member); \
413 static struct freq_attr throttle_attr_##name = __ATTR_RO(name) \
415 throttle_attr(unthrottle, reason[NO_THROTTLE]);
416 throttle_attr(powercap, reason[POWERCAP]);
417 throttle_attr(overtemp, reason[CPU_OVERTEMP]);
418 throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
419 throttle_attr(overcurrent, reason[OVERCURRENT]);
420 throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
421 throttle_attr(turbo_stat, throttle_turbo);
422 throttle_attr(sub_turbo_stat, throttle_sub_turbo);
424 static struct attribute *throttle_attrs[] = {
425 &throttle_attr_unthrottle.attr,
426 &throttle_attr_powercap.attr,
427 &throttle_attr_overtemp.attr,
428 &throttle_attr_supply_fault.attr,
429 &throttle_attr_overcurrent.attr,
430 &throttle_attr_occ_reset.attr,
431 &throttle_attr_turbo_stat.attr,
432 &throttle_attr_sub_turbo_stat.attr,
436 static const struct attribute_group throttle_attr_grp = {
437 .name = "throttle_stats",
438 .attrs = throttle_attrs,
441 /* Helper routines */
443 /* Access helpers to power mgt SPR */
445 static inline unsigned long get_pmspr(unsigned long sprn)
449 return mfspr(SPRN_PMCR);
452 return mfspr(SPRN_PMICR);
455 return mfspr(SPRN_PMSR);
460 static inline void set_pmspr(unsigned long sprn, unsigned long val)
464 mtspr(SPRN_PMCR, val);
468 mtspr(SPRN_PMICR, val);
475 * Use objects of this type to query/update
476 * pstates on a remote CPU via smp_call_function.
478 struct powernv_smp_call_data {
485 * powernv_read_cpu_freq: Reads the current frequency on this CPU.
487 * Called via smp_call_function.
489 * Note: The caller of the smp_call_function should pass an argument of
490 * the type 'struct powernv_smp_call_data *' along with this function.
492 * The current frequency on this CPU will be returned via
493 * ((struct powernv_smp_call_data *)arg)->freq;
495 static void powernv_read_cpu_freq(void *arg)
497 unsigned long pmspr_val;
498 struct powernv_smp_call_data *freq_data = arg;
500 pmspr_val = get_pmspr(SPRN_PMSR);
501 freq_data->pstate_id = extract_local_pstate(pmspr_val);
502 freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
504 pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n",
505 raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
510 * powernv_cpufreq_get: Returns the CPU frequency as reported by the
511 * firmware for CPU 'cpu'. This value is reported through the sysfs
512 * file cpuinfo_cur_freq.
514 static unsigned int powernv_cpufreq_get(unsigned int cpu)
516 struct powernv_smp_call_data freq_data;
518 smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
521 return freq_data.freq;
525 * set_pstate: Sets the pstate on this CPU.
527 * This is called via an smp_call_function.
529 * The caller must ensure that freq_data is of the type
530 * (struct powernv_smp_call_data *) and the pstate_id which needs to be set
531 * on this CPU should be present in freq_data->pstate_id.
533 static void set_pstate(void *data)
536 struct powernv_smp_call_data *freq_data = data;
537 unsigned long pstate_ul = freq_data->pstate_id;
538 unsigned long gpstate_ul = freq_data->gpstate_id;
540 val = get_pmspr(SPRN_PMCR);
541 val = val & 0x0000FFFFFFFFFFFFULL;
543 pstate_ul = pstate_ul & 0xFF;
544 gpstate_ul = gpstate_ul & 0xFF;
546 /* Set both global(bits 56..63) and local(bits 48..55) PStates */
547 val = val | (gpstate_ul << 56) | (pstate_ul << 48);
549 pr_debug("Setting cpu %d pmcr to %016lX\n",
550 raw_smp_processor_id(), val);
551 set_pmspr(SPRN_PMCR, val);
555 * get_nominal_index: Returns the index corresponding to the nominal
556 * pstate in the cpufreq table
558 static inline unsigned int get_nominal_index(void)
560 return powernv_pstate_info.nominal;
563 static void powernv_cpufreq_throttle_check(void *data)
566 unsigned int cpu = smp_processor_id();
569 unsigned int pmsr_pmax_idx;
571 pmsr = get_pmspr(SPRN_PMSR);
572 chip = this_cpu_read(chip_info);
574 /* Check for Pmax Capping */
575 pmsr_pmax = extract_max_pstate(pmsr);
576 pmsr_pmax_idx = pstate_to_idx(pmsr_pmax);
577 if (pmsr_pmax_idx != powernv_pstate_info.max) {
580 chip->throttled = true;
581 if (pmsr_pmax_idx > powernv_pstate_info.nominal) {
582 pr_warn_once("CPU %d on Chip %u has Pmax(%d) reduced below nominal frequency(%d)\n",
583 cpu, chip->id, pmsr_pmax,
584 idx_to_pstate(powernv_pstate_info.nominal));
585 chip->throttle_sub_turbo++;
587 chip->throttle_turbo++;
589 trace_powernv_throttle(chip->id,
590 throttle_reason[chip->throttle_reason],
592 } else if (chip->throttled) {
593 chip->throttled = false;
594 trace_powernv_throttle(chip->id,
595 throttle_reason[chip->throttle_reason],
599 /* Check if Psafe_mode_active is set in PMSR. */
601 if (pmsr & PMSR_PSAFE_ENABLE) {
603 pr_info("Pstate set to safe frequency\n");
606 /* Check if SPR_EM_DISABLE is set in PMSR */
607 if (pmsr & PMSR_SPR_EM_DISABLE) {
609 pr_info("Frequency Control disabled from OS\n");
613 pr_info("PMSR = %16lx\n", pmsr);
614 pr_warn("CPU Frequency could be throttled\n");
619 * calc_global_pstate - Calculate global pstate
620 * @elapsed_time: Elapsed time in milliseconds
621 * @local_pstate_idx: New local pstate
622 * @highest_lpstate_idx: pstate from which its ramping down
624 * Finds the appropriate global pstate based on the pstate from which its
625 * ramping down and the time elapsed in ramping down. It follows a quadratic
626 * equation which ensures that it reaches ramping down to pmin in 5sec.
628 static inline int calc_global_pstate(unsigned int elapsed_time,
629 int highest_lpstate_idx,
630 int local_pstate_idx)
635 * Using ramp_down_percent we get the percentage of rampdown
636 * that we are expecting to be dropping. Difference between
637 * highest_lpstate_idx and powernv_pstate_info.min will give a absolute
638 * number of how many pstates we will drop eventually by the end of
639 * 5 seconds, then just scale it get the number pstates to be dropped.
641 index_diff = ((int)ramp_down_percent(elapsed_time) *
642 (powernv_pstate_info.min - highest_lpstate_idx)) / 100;
644 /* Ensure that global pstate is >= to local pstate */
645 if (highest_lpstate_idx + index_diff >= local_pstate_idx)
646 return local_pstate_idx;
648 return highest_lpstate_idx + index_diff;
651 static inline void queue_gpstate_timer(struct global_pstate_info *gpstates)
653 unsigned int timer_interval;
656 * Setting up timer to fire after GPSTATE_TIMER_INTERVAL ms, But
657 * if it exceeds MAX_RAMP_DOWN_TIME ms for ramp down time.
658 * Set timer such that it fires exactly at MAX_RAMP_DOWN_TIME
659 * seconds of ramp down time.
661 if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL)
662 > MAX_RAMP_DOWN_TIME)
663 timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time;
665 timer_interval = GPSTATE_TIMER_INTERVAL;
667 mod_timer(&gpstates->timer, jiffies + msecs_to_jiffies(timer_interval));
671 * gpstate_timer_handler
673 * @data: pointer to cpufreq_policy on which timer was queued
675 * This handler brings down the global pstate closer to the local pstate
676 * according quadratic equation. Queues a new timer if it is still not equal
679 void gpstate_timer_handler(struct timer_list *t)
681 struct global_pstate_info *gpstates = from_timer(gpstates, t, timer);
682 struct cpufreq_policy *policy = gpstates->policy;
683 int gpstate_idx, lpstate_idx;
685 unsigned int time_diff = jiffies_to_msecs(jiffies)
686 - gpstates->last_sampled_time;
687 struct powernv_smp_call_data freq_data;
689 if (!spin_trylock(&gpstates->gpstate_lock))
693 * If PMCR was last updated was using fast_swtich then
694 * We may have wrong in gpstate->last_lpstate_idx
695 * value. Hence, read from PMCR to get correct data.
697 val = get_pmspr(SPRN_PMCR);
698 freq_data.gpstate_id = extract_global_pstate(val);
699 freq_data.pstate_id = extract_local_pstate(val);
700 if (freq_data.gpstate_id == freq_data.pstate_id) {
701 reset_gpstates(policy);
702 spin_unlock(&gpstates->gpstate_lock);
706 gpstates->last_sampled_time += time_diff;
707 gpstates->elapsed_time += time_diff;
709 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
710 gpstate_idx = pstate_to_idx(freq_data.pstate_id);
711 lpstate_idx = gpstate_idx;
712 reset_gpstates(policy);
713 gpstates->highest_lpstate_idx = gpstate_idx;
715 lpstate_idx = pstate_to_idx(freq_data.pstate_id);
716 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
717 gpstates->highest_lpstate_idx,
720 freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
721 gpstates->last_gpstate_idx = gpstate_idx;
722 gpstates->last_lpstate_idx = lpstate_idx;
724 * If local pstate is equal to global pstate, rampdown is over
725 * So timer is not required to be queued.
727 if (gpstate_idx != gpstates->last_lpstate_idx)
728 queue_gpstate_timer(gpstates);
730 spin_unlock(&gpstates->gpstate_lock);
732 /* Timer may get migrated to a different cpu on cpu hot unplug */
733 smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
737 * powernv_cpufreq_target_index: Sets the frequency corresponding to
738 * the cpufreq table entry indexed by new_index on the cpus in the
741 static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
742 unsigned int new_index)
744 struct powernv_smp_call_data freq_data;
745 unsigned int cur_msec, gpstate_idx;
746 struct global_pstate_info *gpstates = policy->driver_data;
748 if (unlikely(rebooting) && new_index != get_nominal_index())
752 /* we don't want to be preempted while
753 * checking if the CPU frequency has been throttled
756 powernv_cpufreq_throttle_check(NULL);
760 cur_msec = jiffies_to_msecs(get_jiffies_64());
762 spin_lock(&gpstates->gpstate_lock);
763 freq_data.pstate_id = idx_to_pstate(new_index);
765 if (!gpstates->last_sampled_time) {
766 gpstate_idx = new_index;
767 gpstates->highest_lpstate_idx = new_index;
771 if (gpstates->last_gpstate_idx < new_index) {
772 gpstates->elapsed_time += cur_msec -
773 gpstates->last_sampled_time;
776 * If its has been ramping down for more than MAX_RAMP_DOWN_TIME
777 * we should be resetting all global pstate related data. Set it
778 * equal to local pstate to start fresh.
780 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
781 reset_gpstates(policy);
782 gpstates->highest_lpstate_idx = new_index;
783 gpstate_idx = new_index;
785 /* Elaspsed_time is less than 5 seconds, continue to rampdown */
786 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
787 gpstates->highest_lpstate_idx,
791 reset_gpstates(policy);
792 gpstates->highest_lpstate_idx = new_index;
793 gpstate_idx = new_index;
797 * If local pstate is equal to global pstate, rampdown is over
798 * So timer is not required to be queued.
800 if (gpstate_idx != new_index)
801 queue_gpstate_timer(gpstates);
803 del_timer_sync(&gpstates->timer);
806 freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
807 gpstates->last_sampled_time = cur_msec;
808 gpstates->last_gpstate_idx = gpstate_idx;
809 gpstates->last_lpstate_idx = new_index;
811 spin_unlock(&gpstates->gpstate_lock);
814 * Use smp_call_function to send IPI and execute the
815 * mtspr on target CPU. We could do that without IPI
816 * if current CPU is within policy->cpus (core)
818 smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
822 static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
825 struct kernfs_node *kn;
826 struct global_pstate_info *gpstates;
828 base = cpu_first_thread_sibling(policy->cpu);
830 for (i = 0; i < threads_per_core; i++)
831 cpumask_set_cpu(base + i, policy->cpus);
833 kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
837 ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
839 pr_info("Failed to create throttle stats directory for cpu %d\n",
847 gpstates = kzalloc(sizeof(*gpstates), GFP_KERNEL);
851 policy->driver_data = gpstates;
853 /* initialize timer */
854 gpstates->policy = policy;
855 timer_setup(&gpstates->timer, gpstate_timer_handler,
856 TIMER_PINNED | TIMER_DEFERRABLE);
857 gpstates->timer.expires = jiffies +
858 msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
859 spin_lock_init(&gpstates->gpstate_lock);
860 ret = cpufreq_table_validate_and_show(policy, powernv_freqs);
863 kfree(policy->driver_data);
867 policy->fast_switch_possible = true;
871 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
873 /* timer is deleted in cpufreq_cpu_stop() */
874 kfree(policy->driver_data);
879 static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
880 unsigned long action, void *unused)
883 struct cpufreq_policy cpu_policy;
886 for_each_online_cpu(cpu) {
887 cpufreq_get_policy(&cpu_policy, cpu);
888 powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
894 static struct notifier_block powernv_cpufreq_reboot_nb = {
895 .notifier_call = powernv_cpufreq_reboot_notifier,
898 void powernv_cpufreq_work_fn(struct work_struct *work)
900 struct chip *chip = container_of(work, struct chip, throttle);
905 cpumask_and(&mask, &chip->mask, cpu_online_mask);
906 smp_call_function_any(&mask,
907 powernv_cpufreq_throttle_check, NULL, 0);
912 chip->restore = false;
913 for_each_cpu(cpu, &mask) {
915 struct cpufreq_policy policy;
917 cpufreq_get_policy(&policy, cpu);
918 index = cpufreq_table_find_index_c(&policy, policy.cur);
919 powernv_cpufreq_target_index(&policy, index);
920 cpumask_andnot(&mask, &mask, policy.cpus);
926 static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
927 unsigned long msg_type, void *_msg)
929 struct opal_msg *msg = _msg;
930 struct opal_occ_msg omsg;
933 if (msg_type != OPAL_MSG_OCC)
936 omsg.type = be64_to_cpu(msg->params[0]);
941 pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
943 * powernv_cpufreq_throttle_check() is called in
944 * target() callback which can detect the throttle state
945 * for governors like ondemand.
946 * But static governors will not call target() often thus
947 * report throttling here.
951 pr_warn("CPU frequency is throttled for duration\n");
956 pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
959 omsg.chip = be64_to_cpu(msg->params[1]);
960 omsg.throttle_status = be64_to_cpu(msg->params[2]);
965 pr_info("OCC Active, CPU frequency is no longer throttled\n");
967 for (i = 0; i < nr_chips; i++) {
968 chips[i].restore = true;
969 schedule_work(&chips[i].throttle);
975 for (i = 0; i < nr_chips; i++)
976 if (chips[i].id == omsg.chip)
979 if (omsg.throttle_status >= 0 &&
980 omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
981 chips[i].throttle_reason = omsg.throttle_status;
982 chips[i].reason[omsg.throttle_status]++;
985 if (!omsg.throttle_status)
986 chips[i].restore = true;
988 schedule_work(&chips[i].throttle);
993 static struct notifier_block powernv_cpufreq_opal_nb = {
994 .notifier_call = powernv_cpufreq_occ_msg,
999 static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
1001 struct powernv_smp_call_data freq_data;
1002 struct global_pstate_info *gpstates = policy->driver_data;
1004 freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
1005 freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
1006 smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
1007 del_timer_sync(&gpstates->timer);
1010 static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
1011 unsigned int target_freq)
1014 struct powernv_smp_call_data freq_data;
1016 index = cpufreq_table_find_index_dl(policy, target_freq);
1017 freq_data.pstate_id = powernv_freqs[index].driver_data;
1018 freq_data.gpstate_id = powernv_freqs[index].driver_data;
1019 set_pstate(&freq_data);
1021 return powernv_freqs[index].frequency;
1024 static struct cpufreq_driver powernv_cpufreq_driver = {
1025 .name = "powernv-cpufreq",
1026 .flags = CPUFREQ_CONST_LOOPS,
1027 .init = powernv_cpufreq_cpu_init,
1028 .exit = powernv_cpufreq_cpu_exit,
1029 .verify = cpufreq_generic_frequency_table_verify,
1030 .target_index = powernv_cpufreq_target_index,
1031 .fast_switch = powernv_fast_switch,
1032 .get = powernv_cpufreq_get,
1033 .stop_cpu = powernv_cpufreq_stop_cpu,
1034 .attr = powernv_cpu_freq_attr,
1037 static int init_chip_info(void)
1039 unsigned int chip[256];
1040 unsigned int cpu, i;
1041 unsigned int prev_chip_id = UINT_MAX;
1043 for_each_possible_cpu(cpu) {
1044 unsigned int id = cpu_to_chip_id(cpu);
1046 if (prev_chip_id != id) {
1048 chip[nr_chips++] = id;
1052 chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
1056 for (i = 0; i < nr_chips; i++) {
1057 chips[i].id = chip[i];
1058 cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
1059 INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
1060 for_each_cpu(cpu, &chips[i].mask)
1061 per_cpu(chip_info, cpu) = &chips[i];
1067 static inline void clean_chip_info(void)
1072 static inline void unregister_all_notifiers(void)
1074 opal_message_notifier_unregister(OPAL_MSG_OCC,
1075 &powernv_cpufreq_opal_nb);
1076 unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
1079 static int __init powernv_cpufreq_init(void)
1083 /* Don't probe on pseries (guest) platforms */
1084 if (!firmware_has_feature(FW_FEATURE_OPAL))
1087 /* Discover pstates from device tree and init */
1088 rc = init_powernv_pstates();
1092 /* Populate chip info */
1093 rc = init_chip_info();
1097 register_reboot_notifier(&powernv_cpufreq_reboot_nb);
1098 opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
1100 if (powernv_pstate_info.wof_enabled)
1101 powernv_cpufreq_driver.boost_enabled = true;
1103 powernv_cpu_freq_attr[SCALING_BOOST_FREQS_ATTR_INDEX] = NULL;
1105 rc = cpufreq_register_driver(&powernv_cpufreq_driver);
1107 pr_info("Failed to register the cpufreq driver (%d)\n", rc);
1108 goto cleanup_notifiers;
1111 if (powernv_pstate_info.wof_enabled)
1112 cpufreq_enable_boost_support();
1116 unregister_all_notifiers();
1119 pr_info("Platform driver disabled. System does not support PState control\n");
1122 module_init(powernv_cpufreq_init);
1124 static void __exit powernv_cpufreq_exit(void)
1126 cpufreq_unregister_driver(&powernv_cpufreq_driver);
1127 unregister_all_notifiers();
1130 module_exit(powernv_cpufreq_exit);
1132 MODULE_LICENSE("GPL");
1133 MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");