1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * POWERNV cpufreq driver for the IBM POWER processors
5 * (C) Copyright IBM 2014
7 * Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
10 #define pr_fmt(fmt) "powernv-cpufreq: " fmt
12 #include <linux/kernel.h>
13 #include <linux/sysfs.h>
14 #include <linux/cpumask.h>
15 #include <linux/module.h>
16 #include <linux/cpufreq.h>
17 #include <linux/smp.h>
19 #include <linux/reboot.h>
20 #include <linux/slab.h>
21 #include <linux/cpu.h>
22 #include <linux/hashtable.h>
23 #include <trace/events/power.h>
25 #include <asm/cputhreads.h>
26 #include <asm/firmware.h>
28 #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
30 #include <linux/timer.h>
32 #define POWERNV_MAX_PSTATES_ORDER 8
33 #define POWERNV_MAX_PSTATES (1UL << (POWERNV_MAX_PSTATES_ORDER))
34 #define PMSR_PSAFE_ENABLE (1UL << 30)
35 #define PMSR_SPR_EM_DISABLE (1UL << 31)
36 #define MAX_PSTATE_SHIFT 32
37 #define LPSTATE_SHIFT 48
38 #define GPSTATE_SHIFT 56
40 #define MAX_RAMP_DOWN_TIME 5120
42 * On an idle system we want the global pstate to ramp-down from max value to
43 * min over a span of ~5 secs. Also we want it to initially ramp-down slowly and
44 * then ramp-down rapidly later on.
46 * This gives a percentage rampdown for time elapsed in milliseconds.
47 * ramp_down_percentage = ((ms * ms) >> 18)
48 * ~= 3.8 * (sec * sec)
50 * At 0 ms ramp_down_percent = 0
51 * At 5120 ms ramp_down_percent = 100
53 #define ramp_down_percent(time) ((time * time) >> 18)
55 /* Interval after which the timer is queued to bring down global pstate */
56 #define GPSTATE_TIMER_INTERVAL 2000
59 * struct global_pstate_info - Per policy data structure to maintain history of
61 * @highest_lpstate_idx: The local pstate index from which we are
63 * @elapsed_time: Time in ms spent in ramping down from
65 * @last_sampled_time: Time from boot in ms when global pstates were
67 * @last_lpstate_idx: Last set value of local pstate and global
68 * @last_gpstate_idx: pstate in terms of cpufreq table index
69 * @timer: Is used for ramping down if cpu goes idle for
70 * a long time with global pstate held high
71 * @gpstate_lock: A spinlock to maintain synchronization between
72 * routines called by the timer handler and
73 * governer's target_index calls
74 * @policy: Associated CPUFreq policy
76 struct global_pstate_info {
77 int highest_lpstate_idx;
78 unsigned int elapsed_time;
79 unsigned int last_sampled_time;
82 spinlock_t gpstate_lock;
83 struct timer_list timer;
84 struct cpufreq_policy *policy;
87 static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
89 static DEFINE_HASHTABLE(pstate_revmap, POWERNV_MAX_PSTATES_ORDER);
91 * struct pstate_idx_revmap_data: Entry in the hashmap pstate_revmap
92 * indexed by a function of pstate id.
94 * @pstate_id: pstate id for this entry.
96 * @cpufreq_table_idx: Index into the powernv_freqs
97 * cpufreq_frequency_table for frequency
98 * corresponding to pstate_id.
100 * @hentry: hlist_node that hooks this entry into the pstate_revmap
103 struct pstate_idx_revmap_data {
105 unsigned int cpufreq_table_idx;
106 struct hlist_node hentry;
109 static bool rebooting, throttled, occ_reset;
111 static const char * const throttle_reason[] = {
114 "Processor Over Temperature",
115 "Power Supply Failure",
120 enum throttle_reason_type {
124 POWER_SUPPLY_FAILURE,
136 struct work_struct throttle;
138 int throttle_sub_turbo;
139 int reason[OCC_MAX_REASON];
143 static DEFINE_PER_CPU(struct chip *, chip_info);
147 * The set of pstates consists of contiguous integers.
148 * powernv_pstate_info stores the index of the frequency table for
149 * max, min and nominal frequencies. It also stores number of
150 * available frequencies.
152 * powernv_pstate_info.nominal indicates the index to the highest
153 * non-turbo frequency.
155 static struct powernv_pstate_info {
158 unsigned int nominal;
159 unsigned int nr_pstates;
161 } powernv_pstate_info;
163 static inline u8 extract_pstate(u64 pmsr_val, unsigned int shift)
165 return ((pmsr_val >> shift) & 0xFF);
168 #define extract_local_pstate(x) extract_pstate(x, LPSTATE_SHIFT)
169 #define extract_global_pstate(x) extract_pstate(x, GPSTATE_SHIFT)
170 #define extract_max_pstate(x) extract_pstate(x, MAX_PSTATE_SHIFT)
172 /* Use following functions for conversions between pstate_id and index */
175 * idx_to_pstate : Returns the pstate id corresponding to the
176 * frequency in the cpufreq frequency table
177 * powernv_freqs indexed by @i.
179 * If @i is out of bound, this will return the pstate
180 * corresponding to the nominal frequency.
182 static inline u8 idx_to_pstate(unsigned int i)
184 if (unlikely(i >= powernv_pstate_info.nr_pstates)) {
185 pr_warn_once("idx_to_pstate: index %u is out of bound\n", i);
186 return powernv_freqs[powernv_pstate_info.nominal].driver_data;
189 return powernv_freqs[i].driver_data;
193 * pstate_to_idx : Returns the index in the cpufreq frequencytable
194 * powernv_freqs for the frequency whose corresponding
195 * pstate id is @pstate.
197 * If no frequency corresponding to @pstate is found,
198 * this will return the index of the nominal
201 static unsigned int pstate_to_idx(u8 pstate)
203 unsigned int key = pstate % POWERNV_MAX_PSTATES;
204 struct pstate_idx_revmap_data *revmap_data;
206 hash_for_each_possible(pstate_revmap, revmap_data, hentry, key) {
207 if (revmap_data->pstate_id == pstate)
208 return revmap_data->cpufreq_table_idx;
211 pr_warn_once("pstate_to_idx: pstate 0x%x not found\n", pstate);
212 return powernv_pstate_info.nominal;
215 static inline void reset_gpstates(struct cpufreq_policy *policy)
217 struct global_pstate_info *gpstates = policy->driver_data;
219 gpstates->highest_lpstate_idx = 0;
220 gpstates->elapsed_time = 0;
221 gpstates->last_sampled_time = 0;
222 gpstates->last_lpstate_idx = 0;
223 gpstates->last_gpstate_idx = 0;
227 * Initialize the freq table based on data obtained
228 * from the firmware passed via device-tree
230 static int init_powernv_pstates(void)
232 struct device_node *power_mgt;
233 int i, nr_pstates = 0;
234 const __be32 *pstate_ids, *pstate_freqs;
235 u32 len_ids, len_freqs;
236 u32 pstate_min, pstate_max, pstate_nominal;
237 u32 pstate_turbo, pstate_ultra_turbo;
240 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
242 pr_warn("power-mgt node not found\n");
246 if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
247 pr_warn("ibm,pstate-min node not found\n");
251 if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
252 pr_warn("ibm,pstate-max node not found\n");
256 if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
258 pr_warn("ibm,pstate-nominal not found\n");
262 if (of_property_read_u32(power_mgt, "ibm,pstate-ultra-turbo",
263 &pstate_ultra_turbo)) {
264 powernv_pstate_info.wof_enabled = false;
268 if (of_property_read_u32(power_mgt, "ibm,pstate-turbo",
270 powernv_pstate_info.wof_enabled = false;
274 if (pstate_turbo == pstate_ultra_turbo)
275 powernv_pstate_info.wof_enabled = false;
277 powernv_pstate_info.wof_enabled = true;
280 pr_info("cpufreq pstate min 0x%x nominal 0x%x max 0x%x\n", pstate_min,
281 pstate_nominal, pstate_max);
282 pr_info("Workload Optimized Frequency is %s in the platform\n",
283 (powernv_pstate_info.wof_enabled) ? "enabled" : "disabled");
285 pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
287 pr_warn("ibm,pstate-ids not found\n");
291 pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
294 pr_warn("ibm,pstate-frequencies-mhz not found\n");
298 if (len_ids != len_freqs) {
299 pr_warn("Entries in ibm,pstate-ids and "
300 "ibm,pstate-frequencies-mhz does not match\n");
303 nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
305 pr_warn("No PStates found\n");
309 powernv_pstate_info.nr_pstates = nr_pstates;
310 pr_debug("NR PStates %d\n", nr_pstates);
312 for (i = 0; i < nr_pstates; i++) {
313 u32 id = be32_to_cpu(pstate_ids[i]);
314 u32 freq = be32_to_cpu(pstate_freqs[i]);
315 struct pstate_idx_revmap_data *revmap_data;
318 pr_debug("PState id %d freq %d MHz\n", id, freq);
319 powernv_freqs[i].frequency = freq * 1000; /* kHz */
320 powernv_freqs[i].driver_data = id & 0xFF;
322 revmap_data = kmalloc(sizeof(*revmap_data), GFP_KERNEL);
328 revmap_data->pstate_id = id & 0xFF;
329 revmap_data->cpufreq_table_idx = i;
330 key = (revmap_data->pstate_id) % POWERNV_MAX_PSTATES;
331 hash_add(pstate_revmap, &revmap_data->hentry, key);
333 if (id == pstate_max)
334 powernv_pstate_info.max = i;
335 if (id == pstate_nominal)
336 powernv_pstate_info.nominal = i;
337 if (id == pstate_min)
338 powernv_pstate_info.min = i;
340 if (powernv_pstate_info.wof_enabled && id == pstate_turbo) {
343 for (j = i - 1; j >= (int)powernv_pstate_info.max; j--)
344 powernv_freqs[j].flags = CPUFREQ_BOOST_FREQ;
348 /* End of list marker entry */
349 powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
351 of_node_put(power_mgt);
354 of_node_put(power_mgt);
358 /* Returns the CPU frequency corresponding to the pstate_id. */
359 static unsigned int pstate_id_to_freq(u8 pstate_id)
363 i = pstate_to_idx(pstate_id);
364 if (i >= powernv_pstate_info.nr_pstates || i < 0) {
365 pr_warn("PState id 0x%x outside of PState table, reporting nominal id 0x%x instead\n",
366 pstate_id, idx_to_pstate(powernv_pstate_info.nominal));
367 i = powernv_pstate_info.nominal;
370 return powernv_freqs[i].frequency;
374 * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
377 static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
380 return sprintf(buf, "%u\n",
381 powernv_freqs[powernv_pstate_info.nominal].frequency);
384 static struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
385 __ATTR_RO(cpuinfo_nominal_freq);
387 #define SCALING_BOOST_FREQS_ATTR_INDEX 2
389 static struct freq_attr *powernv_cpu_freq_attr[] = {
390 &cpufreq_freq_attr_scaling_available_freqs,
391 &cpufreq_freq_attr_cpuinfo_nominal_freq,
392 &cpufreq_freq_attr_scaling_boost_freqs,
396 #define throttle_attr(name, member) \
397 static ssize_t name##_show(struct cpufreq_policy *policy, char *buf) \
399 struct chip *chip = per_cpu(chip_info, policy->cpu); \
401 return sprintf(buf, "%u\n", chip->member); \
404 static struct freq_attr throttle_attr_##name = __ATTR_RO(name) \
406 throttle_attr(unthrottle, reason[NO_THROTTLE]);
407 throttle_attr(powercap, reason[POWERCAP]);
408 throttle_attr(overtemp, reason[CPU_OVERTEMP]);
409 throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
410 throttle_attr(overcurrent, reason[OVERCURRENT]);
411 throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
412 throttle_attr(turbo_stat, throttle_turbo);
413 throttle_attr(sub_turbo_stat, throttle_sub_turbo);
415 static struct attribute *throttle_attrs[] = {
416 &throttle_attr_unthrottle.attr,
417 &throttle_attr_powercap.attr,
418 &throttle_attr_overtemp.attr,
419 &throttle_attr_supply_fault.attr,
420 &throttle_attr_overcurrent.attr,
421 &throttle_attr_occ_reset.attr,
422 &throttle_attr_turbo_stat.attr,
423 &throttle_attr_sub_turbo_stat.attr,
427 static const struct attribute_group throttle_attr_grp = {
428 .name = "throttle_stats",
429 .attrs = throttle_attrs,
432 /* Helper routines */
434 /* Access helpers to power mgt SPR */
436 static inline unsigned long get_pmspr(unsigned long sprn)
440 return mfspr(SPRN_PMCR);
443 return mfspr(SPRN_PMICR);
446 return mfspr(SPRN_PMSR);
451 static inline void set_pmspr(unsigned long sprn, unsigned long val)
455 mtspr(SPRN_PMCR, val);
459 mtspr(SPRN_PMICR, val);
466 * Use objects of this type to query/update
467 * pstates on a remote CPU via smp_call_function.
469 struct powernv_smp_call_data {
476 * powernv_read_cpu_freq: Reads the current frequency on this CPU.
478 * Called via smp_call_function.
480 * Note: The caller of the smp_call_function should pass an argument of
481 * the type 'struct powernv_smp_call_data *' along with this function.
483 * The current frequency on this CPU will be returned via
484 * ((struct powernv_smp_call_data *)arg)->freq;
486 static void powernv_read_cpu_freq(void *arg)
488 unsigned long pmspr_val;
489 struct powernv_smp_call_data *freq_data = arg;
491 pmspr_val = get_pmspr(SPRN_PMSR);
492 freq_data->pstate_id = extract_local_pstate(pmspr_val);
493 freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
495 pr_debug("cpu %d pmsr %016lX pstate_id 0x%x frequency %d kHz\n",
496 raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
501 * powernv_cpufreq_get: Returns the CPU frequency as reported by the
502 * firmware for CPU 'cpu'. This value is reported through the sysfs
503 * file cpuinfo_cur_freq.
505 static unsigned int powernv_cpufreq_get(unsigned int cpu)
507 struct powernv_smp_call_data freq_data;
509 smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
512 return freq_data.freq;
516 * set_pstate: Sets the pstate on this CPU.
518 * This is called via an smp_call_function.
520 * The caller must ensure that freq_data is of the type
521 * (struct powernv_smp_call_data *) and the pstate_id which needs to be set
522 * on this CPU should be present in freq_data->pstate_id.
524 static void set_pstate(void *data)
527 struct powernv_smp_call_data *freq_data = data;
528 unsigned long pstate_ul = freq_data->pstate_id;
529 unsigned long gpstate_ul = freq_data->gpstate_id;
531 val = get_pmspr(SPRN_PMCR);
532 val = val & 0x0000FFFFFFFFFFFFULL;
534 pstate_ul = pstate_ul & 0xFF;
535 gpstate_ul = gpstate_ul & 0xFF;
537 /* Set both global(bits 56..63) and local(bits 48..55) PStates */
538 val = val | (gpstate_ul << 56) | (pstate_ul << 48);
540 pr_debug("Setting cpu %d pmcr to %016lX\n",
541 raw_smp_processor_id(), val);
542 set_pmspr(SPRN_PMCR, val);
546 * get_nominal_index: Returns the index corresponding to the nominal
547 * pstate in the cpufreq table
549 static inline unsigned int get_nominal_index(void)
551 return powernv_pstate_info.nominal;
554 static void powernv_cpufreq_throttle_check(void *data)
557 unsigned int cpu = smp_processor_id();
560 unsigned int pmsr_pmax_idx;
562 pmsr = get_pmspr(SPRN_PMSR);
563 chip = this_cpu_read(chip_info);
565 /* Check for Pmax Capping */
566 pmsr_pmax = extract_max_pstate(pmsr);
567 pmsr_pmax_idx = pstate_to_idx(pmsr_pmax);
568 if (pmsr_pmax_idx != powernv_pstate_info.max) {
571 chip->throttled = true;
572 if (pmsr_pmax_idx > powernv_pstate_info.nominal) {
573 pr_warn_once("CPU %d on Chip %u has Pmax(0x%x) reduced below that of nominal frequency(0x%x)\n",
574 cpu, chip->id, pmsr_pmax,
575 idx_to_pstate(powernv_pstate_info.nominal));
576 chip->throttle_sub_turbo++;
578 chip->throttle_turbo++;
580 trace_powernv_throttle(chip->id,
581 throttle_reason[chip->throttle_reason],
583 } else if (chip->throttled) {
584 chip->throttled = false;
585 trace_powernv_throttle(chip->id,
586 throttle_reason[chip->throttle_reason],
590 /* Check if Psafe_mode_active is set in PMSR. */
592 if (pmsr & PMSR_PSAFE_ENABLE) {
594 pr_info("Pstate set to safe frequency\n");
597 /* Check if SPR_EM_DISABLE is set in PMSR */
598 if (pmsr & PMSR_SPR_EM_DISABLE) {
600 pr_info("Frequency Control disabled from OS\n");
604 pr_info("PMSR = %16lx\n", pmsr);
605 pr_warn("CPU Frequency could be throttled\n");
610 * calc_global_pstate - Calculate global pstate
611 * @elapsed_time: Elapsed time in milliseconds
612 * @local_pstate_idx: New local pstate
613 * @highest_lpstate_idx: pstate from which its ramping down
615 * Finds the appropriate global pstate based on the pstate from which its
616 * ramping down and the time elapsed in ramping down. It follows a quadratic
617 * equation which ensures that it reaches ramping down to pmin in 5sec.
619 static inline int calc_global_pstate(unsigned int elapsed_time,
620 int highest_lpstate_idx,
621 int local_pstate_idx)
626 * Using ramp_down_percent we get the percentage of rampdown
627 * that we are expecting to be dropping. Difference between
628 * highest_lpstate_idx and powernv_pstate_info.min will give a absolute
629 * number of how many pstates we will drop eventually by the end of
630 * 5 seconds, then just scale it get the number pstates to be dropped.
632 index_diff = ((int)ramp_down_percent(elapsed_time) *
633 (powernv_pstate_info.min - highest_lpstate_idx)) / 100;
635 /* Ensure that global pstate is >= to local pstate */
636 if (highest_lpstate_idx + index_diff >= local_pstate_idx)
637 return local_pstate_idx;
639 return highest_lpstate_idx + index_diff;
642 static inline void queue_gpstate_timer(struct global_pstate_info *gpstates)
644 unsigned int timer_interval;
647 * Setting up timer to fire after GPSTATE_TIMER_INTERVAL ms, But
648 * if it exceeds MAX_RAMP_DOWN_TIME ms for ramp down time.
649 * Set timer such that it fires exactly at MAX_RAMP_DOWN_TIME
650 * seconds of ramp down time.
652 if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL)
653 > MAX_RAMP_DOWN_TIME)
654 timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time;
656 timer_interval = GPSTATE_TIMER_INTERVAL;
658 mod_timer(&gpstates->timer, jiffies + msecs_to_jiffies(timer_interval));
662 * gpstate_timer_handler
664 * @t: Timer context used to fetch global pstate info struct
666 * This handler brings down the global pstate closer to the local pstate
667 * according quadratic equation. Queues a new timer if it is still not equal
670 static void gpstate_timer_handler(struct timer_list *t)
672 struct global_pstate_info *gpstates = from_timer(gpstates, t, timer);
673 struct cpufreq_policy *policy = gpstates->policy;
674 int gpstate_idx, lpstate_idx;
676 unsigned int time_diff = jiffies_to_msecs(jiffies)
677 - gpstates->last_sampled_time;
678 struct powernv_smp_call_data freq_data;
680 if (!spin_trylock(&gpstates->gpstate_lock))
683 * If the timer has migrated to the different cpu then bring
684 * it back to one of the policy->cpus
686 if (!cpumask_test_cpu(raw_smp_processor_id(), policy->cpus)) {
687 gpstates->timer.expires = jiffies + msecs_to_jiffies(1);
688 add_timer_on(&gpstates->timer, cpumask_first(policy->cpus));
689 spin_unlock(&gpstates->gpstate_lock);
694 * If PMCR was last updated was using fast_swtich then
695 * We may have wrong in gpstate->last_lpstate_idx
696 * value. Hence, read from PMCR to get correct data.
698 val = get_pmspr(SPRN_PMCR);
699 freq_data.gpstate_id = extract_global_pstate(val);
700 freq_data.pstate_id = extract_local_pstate(val);
701 if (freq_data.gpstate_id == freq_data.pstate_id) {
702 reset_gpstates(policy);
703 spin_unlock(&gpstates->gpstate_lock);
707 gpstates->last_sampled_time += time_diff;
708 gpstates->elapsed_time += time_diff;
710 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
711 gpstate_idx = pstate_to_idx(freq_data.pstate_id);
712 lpstate_idx = gpstate_idx;
713 reset_gpstates(policy);
714 gpstates->highest_lpstate_idx = gpstate_idx;
716 lpstate_idx = pstate_to_idx(freq_data.pstate_id);
717 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
718 gpstates->highest_lpstate_idx,
721 freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
722 gpstates->last_gpstate_idx = gpstate_idx;
723 gpstates->last_lpstate_idx = lpstate_idx;
725 * If local pstate is equal to global pstate, rampdown is over
726 * So timer is not required to be queued.
728 if (gpstate_idx != gpstates->last_lpstate_idx)
729 queue_gpstate_timer(gpstates);
731 set_pstate(&freq_data);
732 spin_unlock(&gpstates->gpstate_lock);
736 * powernv_cpufreq_target_index: Sets the frequency corresponding to
737 * the cpufreq table entry indexed by new_index on the cpus in the
740 static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
741 unsigned int new_index)
743 struct powernv_smp_call_data freq_data;
744 unsigned int cur_msec, gpstate_idx;
745 struct global_pstate_info *gpstates = policy->driver_data;
747 if (unlikely(rebooting) && new_index != get_nominal_index())
751 /* we don't want to be preempted while
752 * checking if the CPU frequency has been throttled
755 powernv_cpufreq_throttle_check(NULL);
759 cur_msec = jiffies_to_msecs(get_jiffies_64());
761 freq_data.pstate_id = idx_to_pstate(new_index);
763 freq_data.gpstate_id = freq_data.pstate_id;
767 spin_lock(&gpstates->gpstate_lock);
769 if (!gpstates->last_sampled_time) {
770 gpstate_idx = new_index;
771 gpstates->highest_lpstate_idx = new_index;
775 if (gpstates->last_gpstate_idx < new_index) {
776 gpstates->elapsed_time += cur_msec -
777 gpstates->last_sampled_time;
780 * If its has been ramping down for more than MAX_RAMP_DOWN_TIME
781 * we should be resetting all global pstate related data. Set it
782 * equal to local pstate to start fresh.
784 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
785 reset_gpstates(policy);
786 gpstates->highest_lpstate_idx = new_index;
787 gpstate_idx = new_index;
789 /* Elaspsed_time is less than 5 seconds, continue to rampdown */
790 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
791 gpstates->highest_lpstate_idx,
795 reset_gpstates(policy);
796 gpstates->highest_lpstate_idx = new_index;
797 gpstate_idx = new_index;
801 * If local pstate is equal to global pstate, rampdown is over
802 * So timer is not required to be queued.
804 if (gpstate_idx != new_index)
805 queue_gpstate_timer(gpstates);
807 del_timer_sync(&gpstates->timer);
810 freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
811 gpstates->last_sampled_time = cur_msec;
812 gpstates->last_gpstate_idx = gpstate_idx;
813 gpstates->last_lpstate_idx = new_index;
815 spin_unlock(&gpstates->gpstate_lock);
819 * Use smp_call_function to send IPI and execute the
820 * mtspr on target CPU. We could do that without IPI
821 * if current CPU is within policy->cpus (core)
823 smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
827 static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
830 struct kernfs_node *kn;
831 struct global_pstate_info *gpstates;
833 base = cpu_first_thread_sibling(policy->cpu);
835 for (i = 0; i < threads_per_core; i++)
836 cpumask_set_cpu(base + i, policy->cpus);
838 kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
842 ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
844 pr_info("Failed to create throttle stats directory for cpu %d\n",
852 policy->freq_table = powernv_freqs;
853 policy->fast_switch_possible = true;
855 if (pvr_version_is(PVR_POWER9))
858 /* Initialise Gpstate ramp-down timer only on POWER8 */
859 gpstates = kzalloc(sizeof(*gpstates), GFP_KERNEL);
863 policy->driver_data = gpstates;
865 /* initialize timer */
866 gpstates->policy = policy;
867 timer_setup(&gpstates->timer, gpstate_timer_handler,
868 TIMER_PINNED | TIMER_DEFERRABLE);
869 gpstates->timer.expires = jiffies +
870 msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
871 spin_lock_init(&gpstates->gpstate_lock);
876 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
878 /* timer is deleted in cpufreq_cpu_stop() */
879 kfree(policy->driver_data);
884 static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
885 unsigned long action, void *unused)
888 struct cpufreq_policy cpu_policy;
891 for_each_online_cpu(cpu) {
892 cpufreq_get_policy(&cpu_policy, cpu);
893 powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
899 static struct notifier_block powernv_cpufreq_reboot_nb = {
900 .notifier_call = powernv_cpufreq_reboot_notifier,
903 static void powernv_cpufreq_work_fn(struct work_struct *work)
905 struct chip *chip = container_of(work, struct chip, throttle);
906 struct cpufreq_policy *policy;
911 cpumask_and(&mask, &chip->mask, cpu_online_mask);
912 smp_call_function_any(&mask,
913 powernv_cpufreq_throttle_check, NULL, 0);
918 chip->restore = false;
919 for_each_cpu(cpu, &mask) {
922 policy = cpufreq_cpu_get(cpu);
925 index = cpufreq_table_find_index_c(policy, policy->cur);
926 powernv_cpufreq_target_index(policy, index);
927 cpumask_andnot(&mask, &mask, policy->cpus);
928 cpufreq_cpu_put(policy);
934 static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
935 unsigned long msg_type, void *_msg)
937 struct opal_msg *msg = _msg;
938 struct opal_occ_msg omsg;
941 if (msg_type != OPAL_MSG_OCC)
944 omsg.type = be64_to_cpu(msg->params[0]);
949 pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
951 * powernv_cpufreq_throttle_check() is called in
952 * target() callback which can detect the throttle state
953 * for governors like ondemand.
954 * But static governors will not call target() often thus
955 * report throttling here.
959 pr_warn("CPU frequency is throttled for duration\n");
964 pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
967 omsg.chip = be64_to_cpu(msg->params[1]);
968 omsg.throttle_status = be64_to_cpu(msg->params[2]);
973 pr_info("OCC Active, CPU frequency is no longer throttled\n");
975 for (i = 0; i < nr_chips; i++) {
976 chips[i].restore = true;
977 schedule_work(&chips[i].throttle);
983 for (i = 0; i < nr_chips; i++)
984 if (chips[i].id == omsg.chip)
987 if (omsg.throttle_status >= 0 &&
988 omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
989 chips[i].throttle_reason = omsg.throttle_status;
990 chips[i].reason[omsg.throttle_status]++;
993 if (!omsg.throttle_status)
994 chips[i].restore = true;
996 schedule_work(&chips[i].throttle);
1001 static struct notifier_block powernv_cpufreq_opal_nb = {
1002 .notifier_call = powernv_cpufreq_occ_msg,
1007 static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
1009 struct powernv_smp_call_data freq_data;
1010 struct global_pstate_info *gpstates = policy->driver_data;
1012 freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
1013 freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
1014 smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
1016 del_timer_sync(&gpstates->timer);
1019 static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
1020 unsigned int target_freq)
1023 struct powernv_smp_call_data freq_data;
1025 index = cpufreq_table_find_index_dl(policy, target_freq);
1026 freq_data.pstate_id = powernv_freqs[index].driver_data;
1027 freq_data.gpstate_id = powernv_freqs[index].driver_data;
1028 set_pstate(&freq_data);
1030 return powernv_freqs[index].frequency;
1033 static struct cpufreq_driver powernv_cpufreq_driver = {
1034 .name = "powernv-cpufreq",
1035 .flags = CPUFREQ_CONST_LOOPS,
1036 .init = powernv_cpufreq_cpu_init,
1037 .exit = powernv_cpufreq_cpu_exit,
1038 .verify = cpufreq_generic_frequency_table_verify,
1039 .target_index = powernv_cpufreq_target_index,
1040 .fast_switch = powernv_fast_switch,
1041 .get = powernv_cpufreq_get,
1042 .stop_cpu = powernv_cpufreq_stop_cpu,
1043 .attr = powernv_cpu_freq_attr,
1046 static int init_chip_info(void)
1049 unsigned int cpu, i;
1050 unsigned int prev_chip_id = UINT_MAX;
1053 chip = kcalloc(num_possible_cpus(), sizeof(*chip), GFP_KERNEL);
1057 for_each_possible_cpu(cpu) {
1058 unsigned int id = cpu_to_chip_id(cpu);
1060 if (prev_chip_id != id) {
1062 chip[nr_chips++] = id;
1066 chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
1069 goto free_and_return;
1072 for (i = 0; i < nr_chips; i++) {
1073 chips[i].id = chip[i];
1074 cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
1075 INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
1076 for_each_cpu(cpu, &chips[i].mask)
1077 per_cpu(chip_info, cpu) = &chips[i];
1085 static inline void clean_chip_info(void)
1089 /* flush any pending work items */
1091 for (i = 0; i < nr_chips; i++)
1092 cancel_work_sync(&chips[i].throttle);
1096 static inline void unregister_all_notifiers(void)
1098 opal_message_notifier_unregister(OPAL_MSG_OCC,
1099 &powernv_cpufreq_opal_nb);
1100 unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
1103 static int __init powernv_cpufreq_init(void)
1107 /* Don't probe on pseries (guest) platforms */
1108 if (!firmware_has_feature(FW_FEATURE_OPAL))
1111 /* Discover pstates from device tree and init */
1112 rc = init_powernv_pstates();
1116 /* Populate chip info */
1117 rc = init_chip_info();
1121 if (powernv_pstate_info.wof_enabled)
1122 powernv_cpufreq_driver.boost_enabled = true;
1124 powernv_cpu_freq_attr[SCALING_BOOST_FREQS_ATTR_INDEX] = NULL;
1126 rc = cpufreq_register_driver(&powernv_cpufreq_driver);
1128 pr_info("Failed to register the cpufreq driver (%d)\n", rc);
1132 if (powernv_pstate_info.wof_enabled)
1133 cpufreq_enable_boost_support();
1135 register_reboot_notifier(&powernv_cpufreq_reboot_nb);
1136 opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
1142 pr_info("Platform driver disabled. System does not support PState control\n");
1145 module_init(powernv_cpufreq_init);
1147 static void __exit powernv_cpufreq_exit(void)
1149 cpufreq_unregister_driver(&powernv_cpufreq_driver);
1150 unregister_all_notifiers();
1153 module_exit(powernv_cpufreq_exit);
1155 MODULE_LICENSE("GPL");
1156 MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");