Merge tag 'mips_5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
[linux-2.6-microblaze.git] / drivers / cpufreq / powernv-cpufreq.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * POWERNV cpufreq driver for the IBM POWER processors
4  *
5  * (C) Copyright IBM 2014
6  *
7  * Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
8  */
9
10 #define pr_fmt(fmt)     "powernv-cpufreq: " fmt
11
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>
18 #include <linux/of.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>
24
25 #include <asm/cputhreads.h>
26 #include <asm/firmware.h>
27 #include <asm/reg.h>
28 #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
29 #include <asm/opal.h>
30 #include <linux/timer.h>
31
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
39 #define MAX_NR_CHIPS            32
40
41 #define MAX_RAMP_DOWN_TIME                              5120
42 /*
43  * On an idle system we want the global pstate to ramp-down from max value to
44  * min over a span of ~5 secs. Also we want it to initially ramp-down slowly and
45  * then ramp-down rapidly later on.
46  *
47  * This gives a percentage rampdown for time elapsed in milliseconds.
48  * ramp_down_percentage = ((ms * ms) >> 18)
49  *                      ~= 3.8 * (sec * sec)
50  *
51  * At 0 ms      ramp_down_percent = 0
52  * At 5120 ms   ramp_down_percent = 100
53  */
54 #define ramp_down_percent(time)         ((time * time) >> 18)
55
56 /* Interval after which the timer is queued to bring down global pstate */
57 #define GPSTATE_TIMER_INTERVAL                          2000
58
59 /**
60  * struct global_pstate_info -  Per policy data structure to maintain history of
61  *                              global pstates
62  * @highest_lpstate_idx:        The local pstate index from which we are
63  *                              ramping down
64  * @elapsed_time:               Time in ms spent in ramping down from
65  *                              highest_lpstate_idx
66  * @last_sampled_time:          Time from boot in ms when global pstates were
67  *                              last set
68  * @last_lpstate_idx:           Last set value of local pstate and global
69  * @last_gpstate_idx:           pstate in terms of cpufreq table index
70  * @timer:                      Is used for ramping down if cpu goes idle for
71  *                              a long time with global pstate held high
72  * @gpstate_lock:               A spinlock to maintain synchronization between
73  *                              routines called by the timer handler and
74  *                              governer's target_index calls
75  * @policy:                     Associated CPUFreq policy
76  */
77 struct global_pstate_info {
78         int highest_lpstate_idx;
79         unsigned int elapsed_time;
80         unsigned int last_sampled_time;
81         int last_lpstate_idx;
82         int last_gpstate_idx;
83         spinlock_t gpstate_lock;
84         struct timer_list timer;
85         struct cpufreq_policy *policy;
86 };
87
88 static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
89
90 static DEFINE_HASHTABLE(pstate_revmap, POWERNV_MAX_PSTATES_ORDER);
91 /**
92  * struct pstate_idx_revmap_data: Entry in the hashmap pstate_revmap
93  *                                indexed by a function of pstate id.
94  *
95  * @pstate_id: pstate id for this entry.
96  *
97  * @cpufreq_table_idx: Index into the powernv_freqs
98  *                     cpufreq_frequency_table for frequency
99  *                     corresponding to pstate_id.
100  *
101  * @hentry: hlist_node that hooks this entry into the pstate_revmap
102  *          hashtable
103  */
104 struct pstate_idx_revmap_data {
105         u8 pstate_id;
106         unsigned int cpufreq_table_idx;
107         struct hlist_node hentry;
108 };
109
110 static bool rebooting, throttled, occ_reset;
111
112 static const char * const throttle_reason[] = {
113         "No throttling",
114         "Power Cap",
115         "Processor Over Temperature",
116         "Power Supply Failure",
117         "Over Current",
118         "OCC Reset"
119 };
120
121 enum throttle_reason_type {
122         NO_THROTTLE = 0,
123         POWERCAP,
124         CPU_OVERTEMP,
125         POWER_SUPPLY_FAILURE,
126         OVERCURRENT,
127         OCC_RESET_THROTTLE,
128         OCC_MAX_REASON
129 };
130
131 static struct chip {
132         unsigned int id;
133         bool throttled;
134         bool restore;
135         u8 throttle_reason;
136         cpumask_t mask;
137         struct work_struct throttle;
138         int throttle_turbo;
139         int throttle_sub_turbo;
140         int reason[OCC_MAX_REASON];
141 } *chips;
142
143 static int nr_chips;
144 static DEFINE_PER_CPU(struct chip *, chip_info);
145
146 /*
147  * Note:
148  * The set of pstates consists of contiguous integers.
149  * powernv_pstate_info stores the index of the frequency table for
150  * max, min and nominal frequencies. It also stores number of
151  * available frequencies.
152  *
153  * powernv_pstate_info.nominal indicates the index to the highest
154  * non-turbo frequency.
155  */
156 static struct powernv_pstate_info {
157         unsigned int min;
158         unsigned int max;
159         unsigned int nominal;
160         unsigned int nr_pstates;
161         bool wof_enabled;
162 } powernv_pstate_info;
163
164 static inline u8 extract_pstate(u64 pmsr_val, unsigned int shift)
165 {
166         return ((pmsr_val >> shift) & 0xFF);
167 }
168
169 #define extract_local_pstate(x) extract_pstate(x, LPSTATE_SHIFT)
170 #define extract_global_pstate(x) extract_pstate(x, GPSTATE_SHIFT)
171 #define extract_max_pstate(x)  extract_pstate(x, MAX_PSTATE_SHIFT)
172
173 /* Use following functions for conversions between pstate_id and index */
174
175 /*
176  * idx_to_pstate : Returns the pstate id corresponding to the
177  *                 frequency in the cpufreq frequency table
178  *                 powernv_freqs indexed by @i.
179  *
180  *                 If @i is out of bound, this will return the pstate
181  *                 corresponding to the nominal frequency.
182  */
183 static inline u8 idx_to_pstate(unsigned int i)
184 {
185         if (unlikely(i >= powernv_pstate_info.nr_pstates)) {
186                 pr_warn_once("idx_to_pstate: index %u is out of bound\n", i);
187                 return powernv_freqs[powernv_pstate_info.nominal].driver_data;
188         }
189
190         return powernv_freqs[i].driver_data;
191 }
192
193 /*
194  * pstate_to_idx : Returns the index in the cpufreq frequencytable
195  *                 powernv_freqs for the frequency whose corresponding
196  *                 pstate id is @pstate.
197  *
198  *                 If no frequency corresponding to @pstate is found,
199  *                 this will return the index of the nominal
200  *                 frequency.
201  */
202 static unsigned int pstate_to_idx(u8 pstate)
203 {
204         unsigned int key = pstate % POWERNV_MAX_PSTATES;
205         struct pstate_idx_revmap_data *revmap_data;
206
207         hash_for_each_possible(pstate_revmap, revmap_data, hentry, key) {
208                 if (revmap_data->pstate_id == pstate)
209                         return revmap_data->cpufreq_table_idx;
210         }
211
212         pr_warn_once("pstate_to_idx: pstate 0x%x not found\n", pstate);
213         return powernv_pstate_info.nominal;
214 }
215
216 static inline void reset_gpstates(struct cpufreq_policy *policy)
217 {
218         struct global_pstate_info *gpstates = policy->driver_data;
219
220         gpstates->highest_lpstate_idx = 0;
221         gpstates->elapsed_time = 0;
222         gpstates->last_sampled_time = 0;
223         gpstates->last_lpstate_idx = 0;
224         gpstates->last_gpstate_idx = 0;
225 }
226
227 /*
228  * Initialize the freq table based on data obtained
229  * from the firmware passed via device-tree
230  */
231 static int init_powernv_pstates(void)
232 {
233         struct device_node *power_mgt;
234         int i, nr_pstates = 0;
235         const __be32 *pstate_ids, *pstate_freqs;
236         u32 len_ids, len_freqs;
237         u32 pstate_min, pstate_max, pstate_nominal;
238         u32 pstate_turbo, pstate_ultra_turbo;
239         int rc = -ENODEV;
240
241         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
242         if (!power_mgt) {
243                 pr_warn("power-mgt node not found\n");
244                 return -ENODEV;
245         }
246
247         if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
248                 pr_warn("ibm,pstate-min node not found\n");
249                 goto out;
250         }
251
252         if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
253                 pr_warn("ibm,pstate-max node not found\n");
254                 goto out;
255         }
256
257         if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
258                                  &pstate_nominal)) {
259                 pr_warn("ibm,pstate-nominal not found\n");
260                 goto out;
261         }
262
263         if (of_property_read_u32(power_mgt, "ibm,pstate-ultra-turbo",
264                                  &pstate_ultra_turbo)) {
265                 powernv_pstate_info.wof_enabled = false;
266                 goto next;
267         }
268
269         if (of_property_read_u32(power_mgt, "ibm,pstate-turbo",
270                                  &pstate_turbo)) {
271                 powernv_pstate_info.wof_enabled = false;
272                 goto next;
273         }
274
275         if (pstate_turbo == pstate_ultra_turbo)
276                 powernv_pstate_info.wof_enabled = false;
277         else
278                 powernv_pstate_info.wof_enabled = true;
279
280 next:
281         pr_info("cpufreq pstate min 0x%x nominal 0x%x max 0x%x\n", pstate_min,
282                 pstate_nominal, pstate_max);
283         pr_info("Workload Optimized Frequency is %s in the platform\n",
284                 (powernv_pstate_info.wof_enabled) ? "enabled" : "disabled");
285
286         pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
287         if (!pstate_ids) {
288                 pr_warn("ibm,pstate-ids not found\n");
289                 goto out;
290         }
291
292         pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
293                                       &len_freqs);
294         if (!pstate_freqs) {
295                 pr_warn("ibm,pstate-frequencies-mhz not found\n");
296                 goto out;
297         }
298
299         if (len_ids != len_freqs) {
300                 pr_warn("Entries in ibm,pstate-ids and "
301                         "ibm,pstate-frequencies-mhz does not match\n");
302         }
303
304         nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
305         if (!nr_pstates) {
306                 pr_warn("No PStates found\n");
307                 goto out;
308         }
309
310         powernv_pstate_info.nr_pstates = nr_pstates;
311         pr_debug("NR PStates %d\n", nr_pstates);
312
313         for (i = 0; i < nr_pstates; i++) {
314                 u32 id = be32_to_cpu(pstate_ids[i]);
315                 u32 freq = be32_to_cpu(pstate_freqs[i]);
316                 struct pstate_idx_revmap_data *revmap_data;
317                 unsigned int key;
318
319                 pr_debug("PState id %d freq %d MHz\n", id, freq);
320                 powernv_freqs[i].frequency = freq * 1000; /* kHz */
321                 powernv_freqs[i].driver_data = id & 0xFF;
322
323                 revmap_data = kmalloc(sizeof(*revmap_data), GFP_KERNEL);
324                 if (!revmap_data) {
325                         rc = -ENOMEM;
326                         goto out;
327                 }
328
329                 revmap_data->pstate_id = id & 0xFF;
330                 revmap_data->cpufreq_table_idx = i;
331                 key = (revmap_data->pstate_id) % POWERNV_MAX_PSTATES;
332                 hash_add(pstate_revmap, &revmap_data->hentry, key);
333
334                 if (id == pstate_max)
335                         powernv_pstate_info.max = i;
336                 if (id == pstate_nominal)
337                         powernv_pstate_info.nominal = i;
338                 if (id == pstate_min)
339                         powernv_pstate_info.min = i;
340
341                 if (powernv_pstate_info.wof_enabled && id == pstate_turbo) {
342                         int j;
343
344                         for (j = i - 1; j >= (int)powernv_pstate_info.max; j--)
345                                 powernv_freqs[j].flags = CPUFREQ_BOOST_FREQ;
346                 }
347         }
348
349         /* End of list marker entry */
350         powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
351
352         of_node_put(power_mgt);
353         return 0;
354 out:
355         of_node_put(power_mgt);
356         return rc;
357 }
358
359 /* Returns the CPU frequency corresponding to the pstate_id. */
360 static unsigned int pstate_id_to_freq(u8 pstate_id)
361 {
362         int i;
363
364         i = pstate_to_idx(pstate_id);
365         if (i >= powernv_pstate_info.nr_pstates || i < 0) {
366                 pr_warn("PState id 0x%x outside of PState table, reporting nominal id 0x%x instead\n",
367                         pstate_id, idx_to_pstate(powernv_pstate_info.nominal));
368                 i = powernv_pstate_info.nominal;
369         }
370
371         return powernv_freqs[i].frequency;
372 }
373
374 /*
375  * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
376  * the firmware
377  */
378 static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
379                                         char *buf)
380 {
381         return sprintf(buf, "%u\n",
382                 powernv_freqs[powernv_pstate_info.nominal].frequency);
383 }
384
385 static struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
386         __ATTR_RO(cpuinfo_nominal_freq);
387
388 #define SCALING_BOOST_FREQS_ATTR_INDEX          2
389
390 static struct freq_attr *powernv_cpu_freq_attr[] = {
391         &cpufreq_freq_attr_scaling_available_freqs,
392         &cpufreq_freq_attr_cpuinfo_nominal_freq,
393         &cpufreq_freq_attr_scaling_boost_freqs,
394         NULL,
395 };
396
397 #define throttle_attr(name, member)                                     \
398 static ssize_t name##_show(struct cpufreq_policy *policy, char *buf)    \
399 {                                                                       \
400         struct chip *chip = per_cpu(chip_info, policy->cpu);            \
401                                                                         \
402         return sprintf(buf, "%u\n", chip->member);                      \
403 }                                                                       \
404                                                                         \
405 static struct freq_attr throttle_attr_##name = __ATTR_RO(name)          \
406
407 throttle_attr(unthrottle, reason[NO_THROTTLE]);
408 throttle_attr(powercap, reason[POWERCAP]);
409 throttle_attr(overtemp, reason[CPU_OVERTEMP]);
410 throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
411 throttle_attr(overcurrent, reason[OVERCURRENT]);
412 throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
413 throttle_attr(turbo_stat, throttle_turbo);
414 throttle_attr(sub_turbo_stat, throttle_sub_turbo);
415
416 static struct attribute *throttle_attrs[] = {
417         &throttle_attr_unthrottle.attr,
418         &throttle_attr_powercap.attr,
419         &throttle_attr_overtemp.attr,
420         &throttle_attr_supply_fault.attr,
421         &throttle_attr_overcurrent.attr,
422         &throttle_attr_occ_reset.attr,
423         &throttle_attr_turbo_stat.attr,
424         &throttle_attr_sub_turbo_stat.attr,
425         NULL,
426 };
427
428 static const struct attribute_group throttle_attr_grp = {
429         .name   = "throttle_stats",
430         .attrs  = throttle_attrs,
431 };
432
433 /* Helper routines */
434
435 /* Access helpers to power mgt SPR */
436
437 static inline unsigned long get_pmspr(unsigned long sprn)
438 {
439         switch (sprn) {
440         case SPRN_PMCR:
441                 return mfspr(SPRN_PMCR);
442
443         case SPRN_PMICR:
444                 return mfspr(SPRN_PMICR);
445
446         case SPRN_PMSR:
447                 return mfspr(SPRN_PMSR);
448         }
449         BUG();
450 }
451
452 static inline void set_pmspr(unsigned long sprn, unsigned long val)
453 {
454         switch (sprn) {
455         case SPRN_PMCR:
456                 mtspr(SPRN_PMCR, val);
457                 return;
458
459         case SPRN_PMICR:
460                 mtspr(SPRN_PMICR, val);
461                 return;
462         }
463         BUG();
464 }
465
466 /*
467  * Use objects of this type to query/update
468  * pstates on a remote CPU via smp_call_function.
469  */
470 struct powernv_smp_call_data {
471         unsigned int freq;
472         u8 pstate_id;
473         u8 gpstate_id;
474 };
475
476 /*
477  * powernv_read_cpu_freq: Reads the current frequency on this CPU.
478  *
479  * Called via smp_call_function.
480  *
481  * Note: The caller of the smp_call_function should pass an argument of
482  * the type 'struct powernv_smp_call_data *' along with this function.
483  *
484  * The current frequency on this CPU will be returned via
485  * ((struct powernv_smp_call_data *)arg)->freq;
486  */
487 static void powernv_read_cpu_freq(void *arg)
488 {
489         unsigned long pmspr_val;
490         struct powernv_smp_call_data *freq_data = arg;
491
492         pmspr_val = get_pmspr(SPRN_PMSR);
493         freq_data->pstate_id = extract_local_pstate(pmspr_val);
494         freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
495
496         pr_debug("cpu %d pmsr %016lX pstate_id 0x%x frequency %d kHz\n",
497                  raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
498                  freq_data->freq);
499 }
500
501 /*
502  * powernv_cpufreq_get: Returns the CPU frequency as reported by the
503  * firmware for CPU 'cpu'. This value is reported through the sysfs
504  * file cpuinfo_cur_freq.
505  */
506 static unsigned int powernv_cpufreq_get(unsigned int cpu)
507 {
508         struct powernv_smp_call_data freq_data;
509
510         smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
511                         &freq_data, 1);
512
513         return freq_data.freq;
514 }
515
516 /*
517  * set_pstate: Sets the pstate on this CPU.
518  *
519  * This is called via an smp_call_function.
520  *
521  * The caller must ensure that freq_data is of the type
522  * (struct powernv_smp_call_data *) and the pstate_id which needs to be set
523  * on this CPU should be present in freq_data->pstate_id.
524  */
525 static void set_pstate(void *data)
526 {
527         unsigned long val;
528         struct powernv_smp_call_data *freq_data = data;
529         unsigned long pstate_ul = freq_data->pstate_id;
530         unsigned long gpstate_ul = freq_data->gpstate_id;
531
532         val = get_pmspr(SPRN_PMCR);
533         val = val & 0x0000FFFFFFFFFFFFULL;
534
535         pstate_ul = pstate_ul & 0xFF;
536         gpstate_ul = gpstate_ul & 0xFF;
537
538         /* Set both global(bits 56..63) and local(bits 48..55) PStates */
539         val = val | (gpstate_ul << 56) | (pstate_ul << 48);
540
541         pr_debug("Setting cpu %d pmcr to %016lX\n",
542                         raw_smp_processor_id(), val);
543         set_pmspr(SPRN_PMCR, val);
544 }
545
546 /*
547  * get_nominal_index: Returns the index corresponding to the nominal
548  * pstate in the cpufreq table
549  */
550 static inline unsigned int get_nominal_index(void)
551 {
552         return powernv_pstate_info.nominal;
553 }
554
555 static void powernv_cpufreq_throttle_check(void *data)
556 {
557         struct chip *chip;
558         unsigned int cpu = smp_processor_id();
559         unsigned long pmsr;
560         u8 pmsr_pmax;
561         unsigned int pmsr_pmax_idx;
562
563         pmsr = get_pmspr(SPRN_PMSR);
564         chip = this_cpu_read(chip_info);
565
566         /* Check for Pmax Capping */
567         pmsr_pmax = extract_max_pstate(pmsr);
568         pmsr_pmax_idx = pstate_to_idx(pmsr_pmax);
569         if (pmsr_pmax_idx != powernv_pstate_info.max) {
570                 if (chip->throttled)
571                         goto next;
572                 chip->throttled = true;
573                 if (pmsr_pmax_idx > powernv_pstate_info.nominal) {
574                         pr_warn_once("CPU %d on Chip %u has Pmax(0x%x) reduced below that of nominal frequency(0x%x)\n",
575                                      cpu, chip->id, pmsr_pmax,
576                                      idx_to_pstate(powernv_pstate_info.nominal));
577                         chip->throttle_sub_turbo++;
578                 } else {
579                         chip->throttle_turbo++;
580                 }
581                 trace_powernv_throttle(chip->id,
582                                       throttle_reason[chip->throttle_reason],
583                                       pmsr_pmax);
584         } else if (chip->throttled) {
585                 chip->throttled = false;
586                 trace_powernv_throttle(chip->id,
587                                       throttle_reason[chip->throttle_reason],
588                                       pmsr_pmax);
589         }
590
591         /* Check if Psafe_mode_active is set in PMSR. */
592 next:
593         if (pmsr & PMSR_PSAFE_ENABLE) {
594                 throttled = true;
595                 pr_info("Pstate set to safe frequency\n");
596         }
597
598         /* Check if SPR_EM_DISABLE is set in PMSR */
599         if (pmsr & PMSR_SPR_EM_DISABLE) {
600                 throttled = true;
601                 pr_info("Frequency Control disabled from OS\n");
602         }
603
604         if (throttled) {
605                 pr_info("PMSR = %16lx\n", pmsr);
606                 pr_warn("CPU Frequency could be throttled\n");
607         }
608 }
609
610 /**
611  * calc_global_pstate - Calculate global pstate
612  * @elapsed_time:               Elapsed time in milliseconds
613  * @local_pstate_idx:           New local pstate
614  * @highest_lpstate_idx:        pstate from which its ramping down
615  *
616  * Finds the appropriate global pstate based on the pstate from which its
617  * ramping down and the time elapsed in ramping down. It follows a quadratic
618  * equation which ensures that it reaches ramping down to pmin in 5sec.
619  */
620 static inline int calc_global_pstate(unsigned int elapsed_time,
621                                      int highest_lpstate_idx,
622                                      int local_pstate_idx)
623 {
624         int index_diff;
625
626         /*
627          * Using ramp_down_percent we get the percentage of rampdown
628          * that we are expecting to be dropping. Difference between
629          * highest_lpstate_idx and powernv_pstate_info.min will give a absolute
630          * number of how many pstates we will drop eventually by the end of
631          * 5 seconds, then just scale it get the number pstates to be dropped.
632          */
633         index_diff =  ((int)ramp_down_percent(elapsed_time) *
634                         (powernv_pstate_info.min - highest_lpstate_idx)) / 100;
635
636         /* Ensure that global pstate is >= to local pstate */
637         if (highest_lpstate_idx + index_diff >= local_pstate_idx)
638                 return local_pstate_idx;
639         else
640                 return highest_lpstate_idx + index_diff;
641 }
642
643 static inline void  queue_gpstate_timer(struct global_pstate_info *gpstates)
644 {
645         unsigned int timer_interval;
646
647         /*
648          * Setting up timer to fire after GPSTATE_TIMER_INTERVAL ms, But
649          * if it exceeds MAX_RAMP_DOWN_TIME ms for ramp down time.
650          * Set timer such that it fires exactly at MAX_RAMP_DOWN_TIME
651          * seconds of ramp down time.
652          */
653         if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL)
654              > MAX_RAMP_DOWN_TIME)
655                 timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time;
656         else
657                 timer_interval = GPSTATE_TIMER_INTERVAL;
658
659         mod_timer(&gpstates->timer, jiffies + msecs_to_jiffies(timer_interval));
660 }
661
662 /**
663  * gpstate_timer_handler
664  *
665  * @t: Timer context used to fetch global pstate info struct
666  *
667  * This handler brings down the global pstate closer to the local pstate
668  * according quadratic equation. Queues a new timer if it is still not equal
669  * to local pstate
670  */
671 static void gpstate_timer_handler(struct timer_list *t)
672 {
673         struct global_pstate_info *gpstates = from_timer(gpstates, t, timer);
674         struct cpufreq_policy *policy = gpstates->policy;
675         int gpstate_idx, lpstate_idx;
676         unsigned long val;
677         unsigned int time_diff = jiffies_to_msecs(jiffies)
678                                         - gpstates->last_sampled_time;
679         struct powernv_smp_call_data freq_data;
680
681         if (!spin_trylock(&gpstates->gpstate_lock))
682                 return;
683         /*
684          * If the timer has migrated to the different cpu then bring
685          * it back to one of the policy->cpus
686          */
687         if (!cpumask_test_cpu(raw_smp_processor_id(), policy->cpus)) {
688                 gpstates->timer.expires = jiffies + msecs_to_jiffies(1);
689                 add_timer_on(&gpstates->timer, cpumask_first(policy->cpus));
690                 spin_unlock(&gpstates->gpstate_lock);
691                 return;
692         }
693
694         /*
695          * If PMCR was last updated was using fast_swtich then
696          * We may have wrong in gpstate->last_lpstate_idx
697          * value. Hence, read from PMCR to get correct data.
698          */
699         val = get_pmspr(SPRN_PMCR);
700         freq_data.gpstate_id = extract_global_pstate(val);
701         freq_data.pstate_id = extract_local_pstate(val);
702         if (freq_data.gpstate_id  == freq_data.pstate_id) {
703                 reset_gpstates(policy);
704                 spin_unlock(&gpstates->gpstate_lock);
705                 return;
706         }
707
708         gpstates->last_sampled_time += time_diff;
709         gpstates->elapsed_time += time_diff;
710
711         if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
712                 gpstate_idx = pstate_to_idx(freq_data.pstate_id);
713                 lpstate_idx = gpstate_idx;
714                 reset_gpstates(policy);
715                 gpstates->highest_lpstate_idx = gpstate_idx;
716         } else {
717                 lpstate_idx = pstate_to_idx(freq_data.pstate_id);
718                 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
719                                                  gpstates->highest_lpstate_idx,
720                                                  lpstate_idx);
721         }
722         freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
723         gpstates->last_gpstate_idx = gpstate_idx;
724         gpstates->last_lpstate_idx = lpstate_idx;
725         /*
726          * If local pstate is equal to global pstate, rampdown is over
727          * So timer is not required to be queued.
728          */
729         if (gpstate_idx != gpstates->last_lpstate_idx)
730                 queue_gpstate_timer(gpstates);
731
732         set_pstate(&freq_data);
733         spin_unlock(&gpstates->gpstate_lock);
734 }
735
736 /*
737  * powernv_cpufreq_target_index: Sets the frequency corresponding to
738  * the cpufreq table entry indexed by new_index on the cpus in the
739  * mask policy->cpus
740  */
741 static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
742                                         unsigned int new_index)
743 {
744         struct powernv_smp_call_data freq_data;
745         unsigned int cur_msec, gpstate_idx;
746         struct global_pstate_info *gpstates = policy->driver_data;
747
748         if (unlikely(rebooting) && new_index != get_nominal_index())
749                 return 0;
750
751         if (!throttled) {
752                 /* we don't want to be preempted while
753                  * checking if the CPU frequency has been throttled
754                  */
755                 preempt_disable();
756                 powernv_cpufreq_throttle_check(NULL);
757                 preempt_enable();
758         }
759
760         cur_msec = jiffies_to_msecs(get_jiffies_64());
761
762         freq_data.pstate_id = idx_to_pstate(new_index);
763         if (!gpstates) {
764                 freq_data.gpstate_id = freq_data.pstate_id;
765                 goto no_gpstate;
766         }
767
768         spin_lock(&gpstates->gpstate_lock);
769
770         if (!gpstates->last_sampled_time) {
771                 gpstate_idx = new_index;
772                 gpstates->highest_lpstate_idx = new_index;
773                 goto gpstates_done;
774         }
775
776         if (gpstates->last_gpstate_idx < new_index) {
777                 gpstates->elapsed_time += cur_msec -
778                                                  gpstates->last_sampled_time;
779
780                 /*
781                  * If its has been ramping down for more than MAX_RAMP_DOWN_TIME
782                  * we should be resetting all global pstate related data. Set it
783                  * equal to local pstate to start fresh.
784                  */
785                 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
786                         reset_gpstates(policy);
787                         gpstates->highest_lpstate_idx = new_index;
788                         gpstate_idx = new_index;
789                 } else {
790                 /* Elaspsed_time is less than 5 seconds, continue to rampdown */
791                         gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
792                                                          gpstates->highest_lpstate_idx,
793                                                          new_index);
794                 }
795         } else {
796                 reset_gpstates(policy);
797                 gpstates->highest_lpstate_idx = new_index;
798                 gpstate_idx = new_index;
799         }
800
801         /*
802          * If local pstate is equal to global pstate, rampdown is over
803          * So timer is not required to be queued.
804          */
805         if (gpstate_idx != new_index)
806                 queue_gpstate_timer(gpstates);
807         else
808                 del_timer_sync(&gpstates->timer);
809
810 gpstates_done:
811         freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
812         gpstates->last_sampled_time = cur_msec;
813         gpstates->last_gpstate_idx = gpstate_idx;
814         gpstates->last_lpstate_idx = new_index;
815
816         spin_unlock(&gpstates->gpstate_lock);
817
818 no_gpstate:
819         /*
820          * Use smp_call_function to send IPI and execute the
821          * mtspr on target CPU.  We could do that without IPI
822          * if current CPU is within policy->cpus (core)
823          */
824         smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
825         return 0;
826 }
827
828 static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
829 {
830         int base, i;
831         struct kernfs_node *kn;
832         struct global_pstate_info *gpstates;
833
834         base = cpu_first_thread_sibling(policy->cpu);
835
836         for (i = 0; i < threads_per_core; i++)
837                 cpumask_set_cpu(base + i, policy->cpus);
838
839         kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
840         if (!kn) {
841                 int ret;
842
843                 ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
844                 if (ret) {
845                         pr_info("Failed to create throttle stats directory for cpu %d\n",
846                                 policy->cpu);
847                         return ret;
848                 }
849         } else {
850                 kernfs_put(kn);
851         }
852
853         policy->freq_table = powernv_freqs;
854         policy->fast_switch_possible = true;
855
856         if (pvr_version_is(PVR_POWER9))
857                 return 0;
858
859         /* Initialise Gpstate ramp-down timer only on POWER8 */
860         gpstates =  kzalloc(sizeof(*gpstates), GFP_KERNEL);
861         if (!gpstates)
862                 return -ENOMEM;
863
864         policy->driver_data = gpstates;
865
866         /* initialize timer */
867         gpstates->policy = policy;
868         timer_setup(&gpstates->timer, gpstate_timer_handler,
869                     TIMER_PINNED | TIMER_DEFERRABLE);
870         gpstates->timer.expires = jiffies +
871                                 msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
872         spin_lock_init(&gpstates->gpstate_lock);
873
874         return 0;
875 }
876
877 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
878 {
879         struct powernv_smp_call_data freq_data;
880         struct global_pstate_info *gpstates = policy->driver_data;
881
882         freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
883         freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
884         smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
885         if (gpstates)
886                 del_timer_sync(&gpstates->timer);
887
888         kfree(policy->driver_data);
889
890         return 0;
891 }
892
893 static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
894                                 unsigned long action, void *unused)
895 {
896         int cpu;
897         struct cpufreq_policy *cpu_policy;
898
899         rebooting = true;
900         for_each_online_cpu(cpu) {
901                 cpu_policy = cpufreq_cpu_get(cpu);
902                 if (!cpu_policy)
903                         continue;
904                 powernv_cpufreq_target_index(cpu_policy, get_nominal_index());
905                 cpufreq_cpu_put(cpu_policy);
906         }
907
908         return NOTIFY_DONE;
909 }
910
911 static struct notifier_block powernv_cpufreq_reboot_nb = {
912         .notifier_call = powernv_cpufreq_reboot_notifier,
913 };
914
915 static void powernv_cpufreq_work_fn(struct work_struct *work)
916 {
917         struct chip *chip = container_of(work, struct chip, throttle);
918         struct cpufreq_policy *policy;
919         unsigned int cpu;
920         cpumask_t mask;
921
922         cpus_read_lock();
923         cpumask_and(&mask, &chip->mask, cpu_online_mask);
924         smp_call_function_any(&mask,
925                               powernv_cpufreq_throttle_check, NULL, 0);
926
927         if (!chip->restore)
928                 goto out;
929
930         chip->restore = false;
931         for_each_cpu(cpu, &mask) {
932                 int index;
933
934                 policy = cpufreq_cpu_get(cpu);
935                 if (!policy)
936                         continue;
937                 index = cpufreq_table_find_index_c(policy, policy->cur, false);
938                 powernv_cpufreq_target_index(policy, index);
939                 cpumask_andnot(&mask, &mask, policy->cpus);
940                 cpufreq_cpu_put(policy);
941         }
942 out:
943         cpus_read_unlock();
944 }
945
946 static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
947                                    unsigned long msg_type, void *_msg)
948 {
949         struct opal_msg *msg = _msg;
950         struct opal_occ_msg omsg;
951         int i;
952
953         if (msg_type != OPAL_MSG_OCC)
954                 return 0;
955
956         omsg.type = be64_to_cpu(msg->params[0]);
957
958         switch (omsg.type) {
959         case OCC_RESET:
960                 occ_reset = true;
961                 pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
962                 /*
963                  * powernv_cpufreq_throttle_check() is called in
964                  * target() callback which can detect the throttle state
965                  * for governors like ondemand.
966                  * But static governors will not call target() often thus
967                  * report throttling here.
968                  */
969                 if (!throttled) {
970                         throttled = true;
971                         pr_warn("CPU frequency is throttled for duration\n");
972                 }
973
974                 break;
975         case OCC_LOAD:
976                 pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
977                 break;
978         case OCC_THROTTLE:
979                 omsg.chip = be64_to_cpu(msg->params[1]);
980                 omsg.throttle_status = be64_to_cpu(msg->params[2]);
981
982                 if (occ_reset) {
983                         occ_reset = false;
984                         throttled = false;
985                         pr_info("OCC Active, CPU frequency is no longer throttled\n");
986
987                         for (i = 0; i < nr_chips; i++) {
988                                 chips[i].restore = true;
989                                 schedule_work(&chips[i].throttle);
990                         }
991
992                         return 0;
993                 }
994
995                 for (i = 0; i < nr_chips; i++)
996                         if (chips[i].id == omsg.chip)
997                                 break;
998
999                 if (omsg.throttle_status >= 0 &&
1000                     omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
1001                         chips[i].throttle_reason = omsg.throttle_status;
1002                         chips[i].reason[omsg.throttle_status]++;
1003                 }
1004
1005                 if (!omsg.throttle_status)
1006                         chips[i].restore = true;
1007
1008                 schedule_work(&chips[i].throttle);
1009         }
1010         return 0;
1011 }
1012
1013 static struct notifier_block powernv_cpufreq_opal_nb = {
1014         .notifier_call  = powernv_cpufreq_occ_msg,
1015         .next           = NULL,
1016         .priority       = 0,
1017 };
1018
1019 static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
1020                                         unsigned int target_freq)
1021 {
1022         int index;
1023         struct powernv_smp_call_data freq_data;
1024
1025         index = cpufreq_table_find_index_dl(policy, target_freq, false);
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);
1029
1030         return powernv_freqs[index].frequency;
1031 }
1032
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         .attr           = powernv_cpu_freq_attr,
1043 };
1044
1045 static int init_chip_info(void)
1046 {
1047         unsigned int *chip;
1048         unsigned int cpu, i;
1049         unsigned int prev_chip_id = UINT_MAX;
1050         cpumask_t *chip_cpu_mask;
1051         int ret = 0;
1052
1053         chip = kcalloc(num_possible_cpus(), sizeof(*chip), GFP_KERNEL);
1054         if (!chip)
1055                 return -ENOMEM;
1056
1057         /* Allocate a chip cpu mask large enough to fit mask for all chips */
1058         chip_cpu_mask = kcalloc(MAX_NR_CHIPS, sizeof(cpumask_t), GFP_KERNEL);
1059         if (!chip_cpu_mask) {
1060                 ret = -ENOMEM;
1061                 goto free_and_return;
1062         }
1063
1064         for_each_possible_cpu(cpu) {
1065                 unsigned int id = cpu_to_chip_id(cpu);
1066
1067                 if (prev_chip_id != id) {
1068                         prev_chip_id = id;
1069                         chip[nr_chips++] = id;
1070                 }
1071                 cpumask_set_cpu(cpu, &chip_cpu_mask[nr_chips-1]);
1072         }
1073
1074         chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
1075         if (!chips) {
1076                 ret = -ENOMEM;
1077                 goto out_free_chip_cpu_mask;
1078         }
1079
1080         for (i = 0; i < nr_chips; i++) {
1081                 chips[i].id = chip[i];
1082                 cpumask_copy(&chips[i].mask, &chip_cpu_mask[i]);
1083                 INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
1084                 for_each_cpu(cpu, &chips[i].mask)
1085                         per_cpu(chip_info, cpu) =  &chips[i];
1086         }
1087
1088 out_free_chip_cpu_mask:
1089         kfree(chip_cpu_mask);
1090 free_and_return:
1091         kfree(chip);
1092         return ret;
1093 }
1094
1095 static inline void clean_chip_info(void)
1096 {
1097         int i;
1098
1099         /* flush any pending work items */
1100         if (chips)
1101                 for (i = 0; i < nr_chips; i++)
1102                         cancel_work_sync(&chips[i].throttle);
1103         kfree(chips);
1104 }
1105
1106 static inline void unregister_all_notifiers(void)
1107 {
1108         opal_message_notifier_unregister(OPAL_MSG_OCC,
1109                                          &powernv_cpufreq_opal_nb);
1110         unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
1111 }
1112
1113 static int __init powernv_cpufreq_init(void)
1114 {
1115         int rc = 0;
1116
1117         /* Don't probe on pseries (guest) platforms */
1118         if (!firmware_has_feature(FW_FEATURE_OPAL))
1119                 return -ENODEV;
1120
1121         /* Discover pstates from device tree and init */
1122         rc = init_powernv_pstates();
1123         if (rc)
1124                 goto out;
1125
1126         /* Populate chip info */
1127         rc = init_chip_info();
1128         if (rc)
1129                 goto out;
1130
1131         if (powernv_pstate_info.wof_enabled)
1132                 powernv_cpufreq_driver.boost_enabled = true;
1133         else
1134                 powernv_cpu_freq_attr[SCALING_BOOST_FREQS_ATTR_INDEX] = NULL;
1135
1136         rc = cpufreq_register_driver(&powernv_cpufreq_driver);
1137         if (rc) {
1138                 pr_info("Failed to register the cpufreq driver (%d)\n", rc);
1139                 goto cleanup;
1140         }
1141
1142         if (powernv_pstate_info.wof_enabled)
1143                 cpufreq_enable_boost_support();
1144
1145         register_reboot_notifier(&powernv_cpufreq_reboot_nb);
1146         opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
1147
1148         return 0;
1149 cleanup:
1150         clean_chip_info();
1151 out:
1152         pr_info("Platform driver disabled. System does not support PState control\n");
1153         return rc;
1154 }
1155 module_init(powernv_cpufreq_init);
1156
1157 static void __exit powernv_cpufreq_exit(void)
1158 {
1159         cpufreq_unregister_driver(&powernv_cpufreq_driver);
1160         unregister_all_notifiers();
1161         clean_chip_info();
1162 }
1163 module_exit(powernv_cpufreq_exit);
1164
1165 MODULE_LICENSE("GPL");
1166 MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");