dt-bindings: can: flexcan: list supported processors
[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
40 #define MAX_RAMP_DOWN_TIME                              5120
41 /*
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.
45  *
46  * This gives a percentage rampdown for time elapsed in milliseconds.
47  * ramp_down_percentage = ((ms * ms) >> 18)
48  *                      ~= 3.8 * (sec * sec)
49  *
50  * At 0 ms      ramp_down_percent = 0
51  * At 5120 ms   ramp_down_percent = 100
52  */
53 #define ramp_down_percent(time)         ((time * time) >> 18)
54
55 /* Interval after which the timer is queued to bring down global pstate */
56 #define GPSTATE_TIMER_INTERVAL                          2000
57
58 /**
59  * struct global_pstate_info -  Per policy data structure to maintain history of
60  *                              global pstates
61  * @highest_lpstate_idx:        The local pstate index from which we are
62  *                              ramping down
63  * @elapsed_time:               Time in ms spent in ramping down from
64  *                              highest_lpstate_idx
65  * @last_sampled_time:          Time from boot in ms when global pstates were
66  *                              last set
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
75  */
76 struct global_pstate_info {
77         int highest_lpstate_idx;
78         unsigned int elapsed_time;
79         unsigned int last_sampled_time;
80         int last_lpstate_idx;
81         int last_gpstate_idx;
82         spinlock_t gpstate_lock;
83         struct timer_list timer;
84         struct cpufreq_policy *policy;
85 };
86
87 static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
88
89 static DEFINE_HASHTABLE(pstate_revmap, POWERNV_MAX_PSTATES_ORDER);
90 /**
91  * struct pstate_idx_revmap_data: Entry in the hashmap pstate_revmap
92  *                                indexed by a function of pstate id.
93  *
94  * @pstate_id: pstate id for this entry.
95  *
96  * @cpufreq_table_idx: Index into the powernv_freqs
97  *                     cpufreq_frequency_table for frequency
98  *                     corresponding to pstate_id.
99  *
100  * @hentry: hlist_node that hooks this entry into the pstate_revmap
101  *          hashtable
102  */
103 struct pstate_idx_revmap_data {
104         u8 pstate_id;
105         unsigned int cpufreq_table_idx;
106         struct hlist_node hentry;
107 };
108
109 static bool rebooting, throttled, occ_reset;
110
111 static const char * const throttle_reason[] = {
112         "No throttling",
113         "Power Cap",
114         "Processor Over Temperature",
115         "Power Supply Failure",
116         "Over Current",
117         "OCC Reset"
118 };
119
120 enum throttle_reason_type {
121         NO_THROTTLE = 0,
122         POWERCAP,
123         CPU_OVERTEMP,
124         POWER_SUPPLY_FAILURE,
125         OVERCURRENT,
126         OCC_RESET_THROTTLE,
127         OCC_MAX_REASON
128 };
129
130 static struct chip {
131         unsigned int id;
132         bool throttled;
133         bool restore;
134         u8 throttle_reason;
135         cpumask_t mask;
136         struct work_struct throttle;
137         int throttle_turbo;
138         int throttle_sub_turbo;
139         int reason[OCC_MAX_REASON];
140 } *chips;
141
142 static int nr_chips;
143 static DEFINE_PER_CPU(struct chip *, chip_info);
144
145 /*
146  * Note:
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.
151  *
152  * powernv_pstate_info.nominal indicates the index to the highest
153  * non-turbo frequency.
154  */
155 static struct powernv_pstate_info {
156         unsigned int min;
157         unsigned int max;
158         unsigned int nominal;
159         unsigned int nr_pstates;
160         bool wof_enabled;
161 } powernv_pstate_info;
162
163 static inline u8 extract_pstate(u64 pmsr_val, unsigned int shift)
164 {
165         return ((pmsr_val >> shift) & 0xFF);
166 }
167
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)
171
172 /* Use following functions for conversions between pstate_id and index */
173
174 /*
175  * idx_to_pstate : Returns the pstate id corresponding to the
176  *                 frequency in the cpufreq frequency table
177  *                 powernv_freqs indexed by @i.
178  *
179  *                 If @i is out of bound, this will return the pstate
180  *                 corresponding to the nominal frequency.
181  */
182 static inline u8 idx_to_pstate(unsigned int i)
183 {
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;
187         }
188
189         return powernv_freqs[i].driver_data;
190 }
191
192 /*
193  * pstate_to_idx : Returns the index in the cpufreq frequencytable
194  *                 powernv_freqs for the frequency whose corresponding
195  *                 pstate id is @pstate.
196  *
197  *                 If no frequency corresponding to @pstate is found,
198  *                 this will return the index of the nominal
199  *                 frequency.
200  */
201 static unsigned int pstate_to_idx(u8 pstate)
202 {
203         unsigned int key = pstate % POWERNV_MAX_PSTATES;
204         struct pstate_idx_revmap_data *revmap_data;
205
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;
209         }
210
211         pr_warn_once("pstate_to_idx: pstate 0x%x not found\n", pstate);
212         return powernv_pstate_info.nominal;
213 }
214
215 static inline void reset_gpstates(struct cpufreq_policy *policy)
216 {
217         struct global_pstate_info *gpstates = policy->driver_data;
218
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;
224 }
225
226 /*
227  * Initialize the freq table based on data obtained
228  * from the firmware passed via device-tree
229  */
230 static int init_powernv_pstates(void)
231 {
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;
238         int rc = -ENODEV;
239
240         power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
241         if (!power_mgt) {
242                 pr_warn("power-mgt node not found\n");
243                 return -ENODEV;
244         }
245
246         if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
247                 pr_warn("ibm,pstate-min node not found\n");
248                 goto out;
249         }
250
251         if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
252                 pr_warn("ibm,pstate-max node not found\n");
253                 goto out;
254         }
255
256         if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
257                                  &pstate_nominal)) {
258                 pr_warn("ibm,pstate-nominal not found\n");
259                 goto out;
260         }
261
262         if (of_property_read_u32(power_mgt, "ibm,pstate-ultra-turbo",
263                                  &pstate_ultra_turbo)) {
264                 powernv_pstate_info.wof_enabled = false;
265                 goto next;
266         }
267
268         if (of_property_read_u32(power_mgt, "ibm,pstate-turbo",
269                                  &pstate_turbo)) {
270                 powernv_pstate_info.wof_enabled = false;
271                 goto next;
272         }
273
274         if (pstate_turbo == pstate_ultra_turbo)
275                 powernv_pstate_info.wof_enabled = false;
276         else
277                 powernv_pstate_info.wof_enabled = true;
278
279 next:
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");
284
285         pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
286         if (!pstate_ids) {
287                 pr_warn("ibm,pstate-ids not found\n");
288                 goto out;
289         }
290
291         pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
292                                       &len_freqs);
293         if (!pstate_freqs) {
294                 pr_warn("ibm,pstate-frequencies-mhz not found\n");
295                 goto out;
296         }
297
298         if (len_ids != len_freqs) {
299                 pr_warn("Entries in ibm,pstate-ids and "
300                         "ibm,pstate-frequencies-mhz does not match\n");
301         }
302
303         nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
304         if (!nr_pstates) {
305                 pr_warn("No PStates found\n");
306                 goto out;
307         }
308
309         powernv_pstate_info.nr_pstates = nr_pstates;
310         pr_debug("NR PStates %d\n", nr_pstates);
311
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;
316                 unsigned int key;
317
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;
321
322                 revmap_data = kmalloc(sizeof(*revmap_data), GFP_KERNEL);
323                 if (!revmap_data) {
324                         rc = -ENOMEM;
325                         goto out;
326                 }
327
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);
332
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;
339
340                 if (powernv_pstate_info.wof_enabled && id == pstate_turbo) {
341                         int j;
342
343                         for (j = i - 1; j >= (int)powernv_pstate_info.max; j--)
344                                 powernv_freqs[j].flags = CPUFREQ_BOOST_FREQ;
345                 }
346         }
347
348         /* End of list marker entry */
349         powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
350
351         of_node_put(power_mgt);
352         return 0;
353 out:
354         of_node_put(power_mgt);
355         return rc;
356 }
357
358 /* Returns the CPU frequency corresponding to the pstate_id. */
359 static unsigned int pstate_id_to_freq(u8 pstate_id)
360 {
361         int i;
362
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;
368         }
369
370         return powernv_freqs[i].frequency;
371 }
372
373 /*
374  * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
375  * the firmware
376  */
377 static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
378                                         char *buf)
379 {
380         return sprintf(buf, "%u\n",
381                 powernv_freqs[powernv_pstate_info.nominal].frequency);
382 }
383
384 static struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
385         __ATTR_RO(cpuinfo_nominal_freq);
386
387 #define SCALING_BOOST_FREQS_ATTR_INDEX          2
388
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,
393         NULL,
394 };
395
396 #define throttle_attr(name, member)                                     \
397 static ssize_t name##_show(struct cpufreq_policy *policy, char *buf)    \
398 {                                                                       \
399         struct chip *chip = per_cpu(chip_info, policy->cpu);            \
400                                                                         \
401         return sprintf(buf, "%u\n", chip->member);                      \
402 }                                                                       \
403                                                                         \
404 static struct freq_attr throttle_attr_##name = __ATTR_RO(name)          \
405
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);
414
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,
424         NULL,
425 };
426
427 static const struct attribute_group throttle_attr_grp = {
428         .name   = "throttle_stats",
429         .attrs  = throttle_attrs,
430 };
431
432 /* Helper routines */
433
434 /* Access helpers to power mgt SPR */
435
436 static inline unsigned long get_pmspr(unsigned long sprn)
437 {
438         switch (sprn) {
439         case SPRN_PMCR:
440                 return mfspr(SPRN_PMCR);
441
442         case SPRN_PMICR:
443                 return mfspr(SPRN_PMICR);
444
445         case SPRN_PMSR:
446                 return mfspr(SPRN_PMSR);
447         }
448         BUG();
449 }
450
451 static inline void set_pmspr(unsigned long sprn, unsigned long val)
452 {
453         switch (sprn) {
454         case SPRN_PMCR:
455                 mtspr(SPRN_PMCR, val);
456                 return;
457
458         case SPRN_PMICR:
459                 mtspr(SPRN_PMICR, val);
460                 return;
461         }
462         BUG();
463 }
464
465 /*
466  * Use objects of this type to query/update
467  * pstates on a remote CPU via smp_call_function.
468  */
469 struct powernv_smp_call_data {
470         unsigned int freq;
471         u8 pstate_id;
472         u8 gpstate_id;
473 };
474
475 /*
476  * powernv_read_cpu_freq: Reads the current frequency on this CPU.
477  *
478  * Called via smp_call_function.
479  *
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.
482  *
483  * The current frequency on this CPU will be returned via
484  * ((struct powernv_smp_call_data *)arg)->freq;
485  */
486 static void powernv_read_cpu_freq(void *arg)
487 {
488         unsigned long pmspr_val;
489         struct powernv_smp_call_data *freq_data = arg;
490
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);
494
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,
497                  freq_data->freq);
498 }
499
500 /*
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.
504  */
505 static unsigned int powernv_cpufreq_get(unsigned int cpu)
506 {
507         struct powernv_smp_call_data freq_data;
508
509         smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
510                         &freq_data, 1);
511
512         return freq_data.freq;
513 }
514
515 /*
516  * set_pstate: Sets the pstate on this CPU.
517  *
518  * This is called via an smp_call_function.
519  *
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.
523  */
524 static void set_pstate(void *data)
525 {
526         unsigned long val;
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;
530
531         val = get_pmspr(SPRN_PMCR);
532         val = val & 0x0000FFFFFFFFFFFFULL;
533
534         pstate_ul = pstate_ul & 0xFF;
535         gpstate_ul = gpstate_ul & 0xFF;
536
537         /* Set both global(bits 56..63) and local(bits 48..55) PStates */
538         val = val | (gpstate_ul << 56) | (pstate_ul << 48);
539
540         pr_debug("Setting cpu %d pmcr to %016lX\n",
541                         raw_smp_processor_id(), val);
542         set_pmspr(SPRN_PMCR, val);
543 }
544
545 /*
546  * get_nominal_index: Returns the index corresponding to the nominal
547  * pstate in the cpufreq table
548  */
549 static inline unsigned int get_nominal_index(void)
550 {
551         return powernv_pstate_info.nominal;
552 }
553
554 static void powernv_cpufreq_throttle_check(void *data)
555 {
556         struct chip *chip;
557         unsigned int cpu = smp_processor_id();
558         unsigned long pmsr;
559         u8 pmsr_pmax;
560         unsigned int pmsr_pmax_idx;
561
562         pmsr = get_pmspr(SPRN_PMSR);
563         chip = this_cpu_read(chip_info);
564
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) {
569                 if (chip->throttled)
570                         goto next;
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++;
577                 } else {
578                         chip->throttle_turbo++;
579                 }
580                 trace_powernv_throttle(chip->id,
581                                       throttle_reason[chip->throttle_reason],
582                                       pmsr_pmax);
583         } else if (chip->throttled) {
584                 chip->throttled = false;
585                 trace_powernv_throttle(chip->id,
586                                       throttle_reason[chip->throttle_reason],
587                                       pmsr_pmax);
588         }
589
590         /* Check if Psafe_mode_active is set in PMSR. */
591 next:
592         if (pmsr & PMSR_PSAFE_ENABLE) {
593                 throttled = true;
594                 pr_info("Pstate set to safe frequency\n");
595         }
596
597         /* Check if SPR_EM_DISABLE is set in PMSR */
598         if (pmsr & PMSR_SPR_EM_DISABLE) {
599                 throttled = true;
600                 pr_info("Frequency Control disabled from OS\n");
601         }
602
603         if (throttled) {
604                 pr_info("PMSR = %16lx\n", pmsr);
605                 pr_warn("CPU Frequency could be throttled\n");
606         }
607 }
608
609 /**
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
614  *
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.
618  */
619 static inline int calc_global_pstate(unsigned int elapsed_time,
620                                      int highest_lpstate_idx,
621                                      int local_pstate_idx)
622 {
623         int index_diff;
624
625         /*
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.
631          */
632         index_diff =  ((int)ramp_down_percent(elapsed_time) *
633                         (powernv_pstate_info.min - highest_lpstate_idx)) / 100;
634
635         /* Ensure that global pstate is >= to local pstate */
636         if (highest_lpstate_idx + index_diff >= local_pstate_idx)
637                 return local_pstate_idx;
638         else
639                 return highest_lpstate_idx + index_diff;
640 }
641
642 static inline void  queue_gpstate_timer(struct global_pstate_info *gpstates)
643 {
644         unsigned int timer_interval;
645
646         /*
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.
651          */
652         if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL)
653              > MAX_RAMP_DOWN_TIME)
654                 timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time;
655         else
656                 timer_interval = GPSTATE_TIMER_INTERVAL;
657
658         mod_timer(&gpstates->timer, jiffies + msecs_to_jiffies(timer_interval));
659 }
660
661 /**
662  * gpstate_timer_handler
663  *
664  * @t: Timer context used to fetch global pstate info struct
665  *
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
668  * to local pstate
669  */
670 static void gpstate_timer_handler(struct timer_list *t)
671 {
672         struct global_pstate_info *gpstates = from_timer(gpstates, t, timer);
673         struct cpufreq_policy *policy = gpstates->policy;
674         int gpstate_idx, lpstate_idx;
675         unsigned long val;
676         unsigned int time_diff = jiffies_to_msecs(jiffies)
677                                         - gpstates->last_sampled_time;
678         struct powernv_smp_call_data freq_data;
679
680         if (!spin_trylock(&gpstates->gpstate_lock))
681                 return;
682         /*
683          * If the timer has migrated to the different cpu then bring
684          * it back to one of the policy->cpus
685          */
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);
690                 return;
691         }
692
693         /*
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.
697          */
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);
704                 return;
705         }
706
707         gpstates->last_sampled_time += time_diff;
708         gpstates->elapsed_time += time_diff;
709
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;
715         } else {
716                 lpstate_idx = pstate_to_idx(freq_data.pstate_id);
717                 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
718                                                  gpstates->highest_lpstate_idx,
719                                                  lpstate_idx);
720         }
721         freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
722         gpstates->last_gpstate_idx = gpstate_idx;
723         gpstates->last_lpstate_idx = lpstate_idx;
724         /*
725          * If local pstate is equal to global pstate, rampdown is over
726          * So timer is not required to be queued.
727          */
728         if (gpstate_idx != gpstates->last_lpstate_idx)
729                 queue_gpstate_timer(gpstates);
730
731         set_pstate(&freq_data);
732         spin_unlock(&gpstates->gpstate_lock);
733 }
734
735 /*
736  * powernv_cpufreq_target_index: Sets the frequency corresponding to
737  * the cpufreq table entry indexed by new_index on the cpus in the
738  * mask policy->cpus
739  */
740 static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
741                                         unsigned int new_index)
742 {
743         struct powernv_smp_call_data freq_data;
744         unsigned int cur_msec, gpstate_idx;
745         struct global_pstate_info *gpstates = policy->driver_data;
746
747         if (unlikely(rebooting) && new_index != get_nominal_index())
748                 return 0;
749
750         if (!throttled) {
751                 /* we don't want to be preempted while
752                  * checking if the CPU frequency has been throttled
753                  */
754                 preempt_disable();
755                 powernv_cpufreq_throttle_check(NULL);
756                 preempt_enable();
757         }
758
759         cur_msec = jiffies_to_msecs(get_jiffies_64());
760
761         freq_data.pstate_id = idx_to_pstate(new_index);
762         if (!gpstates) {
763                 freq_data.gpstate_id = freq_data.pstate_id;
764                 goto no_gpstate;
765         }
766
767         spin_lock(&gpstates->gpstate_lock);
768
769         if (!gpstates->last_sampled_time) {
770                 gpstate_idx = new_index;
771                 gpstates->highest_lpstate_idx = new_index;
772                 goto gpstates_done;
773         }
774
775         if (gpstates->last_gpstate_idx < new_index) {
776                 gpstates->elapsed_time += cur_msec -
777                                                  gpstates->last_sampled_time;
778
779                 /*
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.
783                  */
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;
788                 } else {
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,
792                                                          new_index);
793                 }
794         } else {
795                 reset_gpstates(policy);
796                 gpstates->highest_lpstate_idx = new_index;
797                 gpstate_idx = new_index;
798         }
799
800         /*
801          * If local pstate is equal to global pstate, rampdown is over
802          * So timer is not required to be queued.
803          */
804         if (gpstate_idx != new_index)
805                 queue_gpstate_timer(gpstates);
806         else
807                 del_timer_sync(&gpstates->timer);
808
809 gpstates_done:
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;
814
815         spin_unlock(&gpstates->gpstate_lock);
816
817 no_gpstate:
818         /*
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)
822          */
823         smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
824         return 0;
825 }
826
827 static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
828 {
829         int base, i;
830         struct kernfs_node *kn;
831         struct global_pstate_info *gpstates;
832
833         base = cpu_first_thread_sibling(policy->cpu);
834
835         for (i = 0; i < threads_per_core; i++)
836                 cpumask_set_cpu(base + i, policy->cpus);
837
838         kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
839         if (!kn) {
840                 int ret;
841
842                 ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
843                 if (ret) {
844                         pr_info("Failed to create throttle stats directory for cpu %d\n",
845                                 policy->cpu);
846                         return ret;
847                 }
848         } else {
849                 kernfs_put(kn);
850         }
851
852         policy->freq_table = powernv_freqs;
853         policy->fast_switch_possible = true;
854
855         if (pvr_version_is(PVR_POWER9))
856                 return 0;
857
858         /* Initialise Gpstate ramp-down timer only on POWER8 */
859         gpstates =  kzalloc(sizeof(*gpstates), GFP_KERNEL);
860         if (!gpstates)
861                 return -ENOMEM;
862
863         policy->driver_data = gpstates;
864
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);
872
873         return 0;
874 }
875
876 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
877 {
878         /* timer is deleted in cpufreq_cpu_stop() */
879         kfree(policy->driver_data);
880
881         return 0;
882 }
883
884 static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
885                                 unsigned long action, void *unused)
886 {
887         int cpu;
888         struct cpufreq_policy cpu_policy;
889
890         rebooting = true;
891         for_each_online_cpu(cpu) {
892                 cpufreq_get_policy(&cpu_policy, cpu);
893                 powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
894         }
895
896         return NOTIFY_DONE;
897 }
898
899 static struct notifier_block powernv_cpufreq_reboot_nb = {
900         .notifier_call = powernv_cpufreq_reboot_notifier,
901 };
902
903 static void powernv_cpufreq_work_fn(struct work_struct *work)
904 {
905         struct chip *chip = container_of(work, struct chip, throttle);
906         struct cpufreq_policy *policy;
907         unsigned int cpu;
908         cpumask_t mask;
909
910         get_online_cpus();
911         cpumask_and(&mask, &chip->mask, cpu_online_mask);
912         smp_call_function_any(&mask,
913                               powernv_cpufreq_throttle_check, NULL, 0);
914
915         if (!chip->restore)
916                 goto out;
917
918         chip->restore = false;
919         for_each_cpu(cpu, &mask) {
920                 int index;
921
922                 policy = cpufreq_cpu_get(cpu);
923                 if (!policy)
924                         continue;
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);
929         }
930 out:
931         put_online_cpus();
932 }
933
934 static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
935                                    unsigned long msg_type, void *_msg)
936 {
937         struct opal_msg *msg = _msg;
938         struct opal_occ_msg omsg;
939         int i;
940
941         if (msg_type != OPAL_MSG_OCC)
942                 return 0;
943
944         omsg.type = be64_to_cpu(msg->params[0]);
945
946         switch (omsg.type) {
947         case OCC_RESET:
948                 occ_reset = true;
949                 pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
950                 /*
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.
956                  */
957                 if (!throttled) {
958                         throttled = true;
959                         pr_warn("CPU frequency is throttled for duration\n");
960                 }
961
962                 break;
963         case OCC_LOAD:
964                 pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
965                 break;
966         case OCC_THROTTLE:
967                 omsg.chip = be64_to_cpu(msg->params[1]);
968                 omsg.throttle_status = be64_to_cpu(msg->params[2]);
969
970                 if (occ_reset) {
971                         occ_reset = false;
972                         throttled = false;
973                         pr_info("OCC Active, CPU frequency is no longer throttled\n");
974
975                         for (i = 0; i < nr_chips; i++) {
976                                 chips[i].restore = true;
977                                 schedule_work(&chips[i].throttle);
978                         }
979
980                         return 0;
981                 }
982
983                 for (i = 0; i < nr_chips; i++)
984                         if (chips[i].id == omsg.chip)
985                                 break;
986
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]++;
991                 }
992
993                 if (!omsg.throttle_status)
994                         chips[i].restore = true;
995
996                 schedule_work(&chips[i].throttle);
997         }
998         return 0;
999 }
1000
1001 static struct notifier_block powernv_cpufreq_opal_nb = {
1002         .notifier_call  = powernv_cpufreq_occ_msg,
1003         .next           = NULL,
1004         .priority       = 0,
1005 };
1006
1007 static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
1008 {
1009         struct powernv_smp_call_data freq_data;
1010         struct global_pstate_info *gpstates = policy->driver_data;
1011
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);
1015         if (gpstates)
1016                 del_timer_sync(&gpstates->timer);
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);
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         .stop_cpu       = powernv_cpufreq_stop_cpu,
1043         .attr           = powernv_cpu_freq_attr,
1044 };
1045
1046 static int init_chip_info(void)
1047 {
1048         unsigned int *chip;
1049         unsigned int cpu, i;
1050         unsigned int prev_chip_id = UINT_MAX;
1051         int ret = 0;
1052
1053         chip = kcalloc(num_possible_cpus(), sizeof(*chip), GFP_KERNEL);
1054         if (!chip)
1055                 return -ENOMEM;
1056
1057         for_each_possible_cpu(cpu) {
1058                 unsigned int id = cpu_to_chip_id(cpu);
1059
1060                 if (prev_chip_id != id) {
1061                         prev_chip_id = id;
1062                         chip[nr_chips++] = id;
1063                 }
1064         }
1065
1066         chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
1067         if (!chips) {
1068                 ret = -ENOMEM;
1069                 goto free_and_return;
1070         }
1071
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];
1078         }
1079
1080 free_and_return:
1081         kfree(chip);
1082         return ret;
1083 }
1084
1085 static inline void clean_chip_info(void)
1086 {
1087         int i;
1088
1089         /* flush any pending work items */
1090         if (chips)
1091                 for (i = 0; i < nr_chips; i++)
1092                         cancel_work_sync(&chips[i].throttle);
1093         kfree(chips);
1094 }
1095
1096 static inline void unregister_all_notifiers(void)
1097 {
1098         opal_message_notifier_unregister(OPAL_MSG_OCC,
1099                                          &powernv_cpufreq_opal_nb);
1100         unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
1101 }
1102
1103 static int __init powernv_cpufreq_init(void)
1104 {
1105         int rc = 0;
1106
1107         /* Don't probe on pseries (guest) platforms */
1108         if (!firmware_has_feature(FW_FEATURE_OPAL))
1109                 return -ENODEV;
1110
1111         /* Discover pstates from device tree and init */
1112         rc = init_powernv_pstates();
1113         if (rc)
1114                 goto out;
1115
1116         /* Populate chip info */
1117         rc = init_chip_info();
1118         if (rc)
1119                 goto out;
1120
1121         if (powernv_pstate_info.wof_enabled)
1122                 powernv_cpufreq_driver.boost_enabled = true;
1123         else
1124                 powernv_cpu_freq_attr[SCALING_BOOST_FREQS_ATTR_INDEX] = NULL;
1125
1126         rc = cpufreq_register_driver(&powernv_cpufreq_driver);
1127         if (rc) {
1128                 pr_info("Failed to register the cpufreq driver (%d)\n", rc);
1129                 goto cleanup;
1130         }
1131
1132         if (powernv_pstate_info.wof_enabled)
1133                 cpufreq_enable_boost_support();
1134
1135         register_reboot_notifier(&powernv_cpufreq_reboot_nb);
1136         opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
1137
1138         return 0;
1139 cleanup:
1140         clean_chip_info();
1141 out:
1142         pr_info("Platform driver disabled. System does not support PState control\n");
1143         return rc;
1144 }
1145 module_init(powernv_cpufreq_init);
1146
1147 static void __exit powernv_cpufreq_exit(void)
1148 {
1149         cpufreq_unregister_driver(&powernv_cpufreq_driver);
1150         unregister_all_notifiers();
1151         clean_chip_info();
1152 }
1153 module_exit(powernv_cpufreq_exit);
1154
1155 MODULE_LICENSE("GPL");
1156 MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");