GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / cpufreq / s3c24xx-cpufreq.c
1 /*
2  * Copyright (c) 2006-2008 Simtec Electronics
3  *      http://armlinux.simtec.co.uk/
4  *      Ben Dooks <ben@simtec.co.uk>
5  *
6  * S3C24XX CPU Frequency scaling
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11 */
12
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/interrupt.h>
16 #include <linux/ioport.h>
17 #include <linux/cpufreq.h>
18 #include <linux/cpu.h>
19 #include <linux/clk.h>
20 #include <linux/err.h>
21 #include <linux/io.h>
22 #include <linux/device.h>
23 #include <linux/sysfs.h>
24 #include <linux/slab.h>
25
26 #include <asm/mach/arch.h>
27 #include <asm/mach/map.h>
28
29 #include <plat/cpu.h>
30 #include <plat/cpu-freq-core.h>
31
32 #include <mach/regs-clock.h>
33
34 /* note, cpufreq support deals in kHz, no Hz */
35
36 static struct cpufreq_driver s3c24xx_driver;
37 static struct s3c_cpufreq_config cpu_cur;
38 static struct s3c_iotimings s3c24xx_iotiming;
39 static struct cpufreq_frequency_table *pll_reg;
40 static unsigned int last_target = ~0;
41 static unsigned int ftab_size;
42 static struct cpufreq_frequency_table *ftab;
43
44 static struct clk *_clk_mpll;
45 static struct clk *_clk_xtal;
46 static struct clk *clk_fclk;
47 static struct clk *clk_hclk;
48 static struct clk *clk_pclk;
49 static struct clk *clk_arm;
50
51 #ifdef CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS
52 struct s3c_cpufreq_config *s3c_cpufreq_getconfig(void)
53 {
54         return &cpu_cur;
55 }
56
57 struct s3c_iotimings *s3c_cpufreq_getiotimings(void)
58 {
59         return &s3c24xx_iotiming;
60 }
61 #endif /* CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS */
62
63 static void s3c_cpufreq_getcur(struct s3c_cpufreq_config *cfg)
64 {
65         unsigned long fclk, pclk, hclk, armclk;
66
67         cfg->freq.fclk = fclk = clk_get_rate(clk_fclk);
68         cfg->freq.hclk = hclk = clk_get_rate(clk_hclk);
69         cfg->freq.pclk = pclk = clk_get_rate(clk_pclk);
70         cfg->freq.armclk = armclk = clk_get_rate(clk_arm);
71
72         cfg->pll.driver_data = __raw_readl(S3C2410_MPLLCON);
73         cfg->pll.frequency = fclk;
74
75         cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10);
76
77         cfg->divs.h_divisor = fclk / hclk;
78         cfg->divs.p_divisor = fclk / pclk;
79 }
80
81 static inline void s3c_cpufreq_calc(struct s3c_cpufreq_config *cfg)
82 {
83         unsigned long pll = cfg->pll.frequency;
84
85         cfg->freq.fclk = pll;
86         cfg->freq.hclk = pll / cfg->divs.h_divisor;
87         cfg->freq.pclk = pll / cfg->divs.p_divisor;
88
89         /* convert hclk into 10ths of nanoseconds for io calcs */
90         cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10);
91 }
92
93 static inline int closer(unsigned int target, unsigned int n, unsigned int c)
94 {
95         int diff_cur = abs(target - c);
96         int diff_new = abs(target - n);
97
98         return (diff_new < diff_cur);
99 }
100
101 static void s3c_cpufreq_show(const char *pfx,
102                                  struct s3c_cpufreq_config *cfg)
103 {
104         s3c_freq_dbg("%s: Fvco=%u, F=%lu, A=%lu, H=%lu (%u), P=%lu (%u)\n",
105                      pfx, cfg->pll.frequency, cfg->freq.fclk, cfg->freq.armclk,
106                      cfg->freq.hclk, cfg->divs.h_divisor,
107                      cfg->freq.pclk, cfg->divs.p_divisor);
108 }
109
110 /* functions to wrapper the driver info calls to do the cpu specific work */
111
112 static void s3c_cpufreq_setio(struct s3c_cpufreq_config *cfg)
113 {
114         if (cfg->info->set_iotiming)
115                 (cfg->info->set_iotiming)(cfg, &s3c24xx_iotiming);
116 }
117
118 static int s3c_cpufreq_calcio(struct s3c_cpufreq_config *cfg)
119 {
120         if (cfg->info->calc_iotiming)
121                 return (cfg->info->calc_iotiming)(cfg, &s3c24xx_iotiming);
122
123         return 0;
124 }
125
126 static void s3c_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
127 {
128         (cfg->info->set_refresh)(cfg);
129 }
130
131 static void s3c_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
132 {
133         (cfg->info->set_divs)(cfg);
134 }
135
136 static int s3c_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
137 {
138         return (cfg->info->calc_divs)(cfg);
139 }
140
141 static void s3c_cpufreq_setfvco(struct s3c_cpufreq_config *cfg)
142 {
143         cfg->mpll = _clk_mpll;
144         (cfg->info->set_fvco)(cfg);
145 }
146
147 static inline void s3c_cpufreq_updateclk(struct clk *clk,
148                                          unsigned int freq)
149 {
150         clk_set_rate(clk, freq);
151 }
152
153 static int s3c_cpufreq_settarget(struct cpufreq_policy *policy,
154                                  unsigned int target_freq,
155                                  struct cpufreq_frequency_table *pll)
156 {
157         struct s3c_cpufreq_freqs freqs;
158         struct s3c_cpufreq_config cpu_new;
159         unsigned long flags;
160
161         cpu_new = cpu_cur;  /* copy new from current */
162
163         s3c_cpufreq_show("cur", &cpu_cur);
164
165         /* TODO - check for DMA currently outstanding */
166
167         cpu_new.pll = pll ? *pll : cpu_cur.pll;
168
169         if (pll)
170                 freqs.pll_changing = 1;
171
172         /* update our frequencies */
173
174         cpu_new.freq.armclk = target_freq;
175         cpu_new.freq.fclk = cpu_new.pll.frequency;
176
177         if (s3c_cpufreq_calcdivs(&cpu_new) < 0) {
178                 printk(KERN_ERR "no divisors for %d\n", target_freq);
179                 goto err_notpossible;
180         }
181
182         s3c_freq_dbg("%s: got divs\n", __func__);
183
184         s3c_cpufreq_calc(&cpu_new);
185
186         s3c_freq_dbg("%s: calculated frequencies for new\n", __func__);
187
188         if (cpu_new.freq.hclk != cpu_cur.freq.hclk) {
189                 if (s3c_cpufreq_calcio(&cpu_new) < 0) {
190                         printk(KERN_ERR "%s: no IO timings\n", __func__);
191                         goto err_notpossible;
192                 }
193         }
194
195         s3c_cpufreq_show("new", &cpu_new);
196
197         /* setup our cpufreq parameters */
198
199         freqs.old = cpu_cur.freq;
200         freqs.new = cpu_new.freq;
201
202         freqs.freqs.old = cpu_cur.freq.armclk / 1000;
203         freqs.freqs.new = cpu_new.freq.armclk / 1000;
204
205         /* update f/h/p clock settings before we issue the change
206          * notification, so that drivers do not need to do anything
207          * special if they want to recalculate on CPUFREQ_PRECHANGE. */
208
209         s3c_cpufreq_updateclk(_clk_mpll, cpu_new.pll.frequency);
210         s3c_cpufreq_updateclk(clk_fclk, cpu_new.freq.fclk);
211         s3c_cpufreq_updateclk(clk_hclk, cpu_new.freq.hclk);
212         s3c_cpufreq_updateclk(clk_pclk, cpu_new.freq.pclk);
213
214         /* start the frequency change */
215         cpufreq_freq_transition_begin(policy, &freqs.freqs);
216
217         /* If hclk is staying the same, then we do not need to
218          * re-write the IO or the refresh timings whilst we are changing
219          * speed. */
220
221         local_irq_save(flags);
222
223         /* is our memory clock slowing down? */
224         if (cpu_new.freq.hclk < cpu_cur.freq.hclk) {
225                 s3c_cpufreq_setrefresh(&cpu_new);
226                 s3c_cpufreq_setio(&cpu_new);
227         }
228
229         if (cpu_new.freq.fclk == cpu_cur.freq.fclk) {
230                 /* not changing PLL, just set the divisors */
231
232                 s3c_cpufreq_setdivs(&cpu_new);
233         } else {
234                 if (cpu_new.freq.fclk < cpu_cur.freq.fclk) {
235                         /* slow the cpu down, then set divisors */
236
237                         s3c_cpufreq_setfvco(&cpu_new);
238                         s3c_cpufreq_setdivs(&cpu_new);
239                 } else {
240                         /* set the divisors, then speed up */
241
242                         s3c_cpufreq_setdivs(&cpu_new);
243                         s3c_cpufreq_setfvco(&cpu_new);
244                 }
245         }
246
247         /* did our memory clock speed up */
248         if (cpu_new.freq.hclk > cpu_cur.freq.hclk) {
249                 s3c_cpufreq_setrefresh(&cpu_new);
250                 s3c_cpufreq_setio(&cpu_new);
251         }
252
253         /* update our current settings */
254         cpu_cur = cpu_new;
255
256         local_irq_restore(flags);
257
258         /* notify everyone we've done this */
259         cpufreq_freq_transition_end(policy, &freqs.freqs, 0);
260
261         s3c_freq_dbg("%s: finished\n", __func__);
262         return 0;
263
264  err_notpossible:
265         printk(KERN_ERR "no compatible settings for %d\n", target_freq);
266         return -EINVAL;
267 }
268
269 /* s3c_cpufreq_target
270  *
271  * called by the cpufreq core to adjust the frequency that the CPU
272  * is currently running at.
273  */
274
275 static int s3c_cpufreq_target(struct cpufreq_policy *policy,
276                               unsigned int target_freq,
277                               unsigned int relation)
278 {
279         struct cpufreq_frequency_table *pll;
280         unsigned int index;
281
282         /* avoid repeated calls which cause a needless amout of duplicated
283          * logging output (and CPU time as the calculation process is
284          * done) */
285         if (target_freq == last_target)
286                 return 0;
287
288         last_target = target_freq;
289
290         s3c_freq_dbg("%s: policy %p, target %u, relation %u\n",
291                      __func__, policy, target_freq, relation);
292
293         if (ftab) {
294                 if (cpufreq_frequency_table_target(policy, ftab,
295                                                    target_freq, relation,
296                                                    &index)) {
297                         s3c_freq_dbg("%s: table failed\n", __func__);
298                         return -EINVAL;
299                 }
300
301                 s3c_freq_dbg("%s: adjust %d to entry %d (%u)\n", __func__,
302                              target_freq, index, ftab[index].frequency);
303                 target_freq = ftab[index].frequency;
304         }
305
306         target_freq *= 1000;  /* convert target to Hz */
307
308         /* find the settings for our new frequency */
309
310         if (!pll_reg || cpu_cur.lock_pll) {
311                 /* either we've not got any PLL values, or we've locked
312                  * to the current one. */
313                 pll = NULL;
314         } else {
315                 struct cpufreq_policy tmp_policy;
316                 int ret;
317
318                 /* we keep the cpu pll table in Hz, to ensure we get an
319                  * accurate value for the PLL output. */
320
321                 tmp_policy.min = policy->min * 1000;
322                 tmp_policy.max = policy->max * 1000;
323                 tmp_policy.cpu = policy->cpu;
324
325                 /* cpufreq_frequency_table_target uses a pointer to 'index'
326                  * which is the number of the table entry, not the value of
327                  * the table entry's index field. */
328
329                 ret = cpufreq_frequency_table_target(&tmp_policy, pll_reg,
330                                                      target_freq, relation,
331                                                      &index);
332
333                 if (ret < 0) {
334                         printk(KERN_ERR "%s: no PLL available\n", __func__);
335                         goto err_notpossible;
336                 }
337
338                 pll = pll_reg + index;
339
340                 s3c_freq_dbg("%s: target %u => %u\n",
341                              __func__, target_freq, pll->frequency);
342
343                 target_freq = pll->frequency;
344         }
345
346         return s3c_cpufreq_settarget(policy, target_freq, pll);
347
348  err_notpossible:
349         printk(KERN_ERR "no compatible settings for %d\n", target_freq);
350         return -EINVAL;
351 }
352
353 struct clk *s3c_cpufreq_clk_get(struct device *dev, const char *name)
354 {
355         struct clk *clk;
356
357         clk = clk_get(dev, name);
358         if (IS_ERR(clk))
359                 printk(KERN_ERR "cpufreq: failed to get clock '%s'\n", name);
360
361         return clk;
362 }
363
364 static int s3c_cpufreq_init(struct cpufreq_policy *policy)
365 {
366         policy->clk = clk_arm;
367
368         policy->cpuinfo.transition_latency = cpu_cur.info->latency;
369
370         if (ftab)
371                 return cpufreq_table_validate_and_show(policy, ftab);
372
373         return 0;
374 }
375
376 static int __init s3c_cpufreq_initclks(void)
377 {
378         _clk_mpll = s3c_cpufreq_clk_get(NULL, "mpll");
379         _clk_xtal = s3c_cpufreq_clk_get(NULL, "xtal");
380         clk_fclk = s3c_cpufreq_clk_get(NULL, "fclk");
381         clk_hclk = s3c_cpufreq_clk_get(NULL, "hclk");
382         clk_pclk = s3c_cpufreq_clk_get(NULL, "pclk");
383         clk_arm = s3c_cpufreq_clk_get(NULL, "armclk");
384
385         if (IS_ERR(clk_fclk) || IS_ERR(clk_hclk) || IS_ERR(clk_pclk) ||
386             IS_ERR(_clk_mpll) || IS_ERR(clk_arm) || IS_ERR(_clk_xtal)) {
387                 printk(KERN_ERR "%s: could not get clock(s)\n", __func__);
388                 return -ENOENT;
389         }
390
391         printk(KERN_INFO "%s: clocks f=%lu,h=%lu,p=%lu,a=%lu\n", __func__,
392                clk_get_rate(clk_fclk) / 1000,
393                clk_get_rate(clk_hclk) / 1000,
394                clk_get_rate(clk_pclk) / 1000,
395                clk_get_rate(clk_arm) / 1000);
396
397         return 0;
398 }
399
400 #ifdef CONFIG_PM
401 static struct cpufreq_frequency_table suspend_pll;
402 static unsigned int suspend_freq;
403
404 static int s3c_cpufreq_suspend(struct cpufreq_policy *policy)
405 {
406         suspend_pll.frequency = clk_get_rate(_clk_mpll);
407         suspend_pll.driver_data = __raw_readl(S3C2410_MPLLCON);
408         suspend_freq = clk_get_rate(clk_arm);
409
410         return 0;
411 }
412
413 static int s3c_cpufreq_resume(struct cpufreq_policy *policy)
414 {
415         int ret;
416
417         s3c_freq_dbg("%s: resuming with policy %p\n", __func__, policy);
418
419         last_target = ~0;       /* invalidate last_target setting */
420
421         /* whilst we will be called later on, we try and re-set the
422          * cpu frequencies as soon as possible so that we do not end
423          * up resuming devices and then immediately having to re-set
424          * a number of settings once these devices have restarted.
425          *
426          * as a note, it is expected devices are not used until they
427          * have been un-suspended and at that time they should have
428          * used the updated clock settings.
429          */
430
431         ret = s3c_cpufreq_settarget(NULL, suspend_freq, &suspend_pll);
432         if (ret) {
433                 printk(KERN_ERR "%s: failed to reset pll/freq\n", __func__);
434                 return ret;
435         }
436
437         return 0;
438 }
439 #else
440 #define s3c_cpufreq_resume NULL
441 #define s3c_cpufreq_suspend NULL
442 #endif
443
444 static struct cpufreq_driver s3c24xx_driver = {
445         .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
446         .target         = s3c_cpufreq_target,
447         .get            = cpufreq_generic_get,
448         .init           = s3c_cpufreq_init,
449         .suspend        = s3c_cpufreq_suspend,
450         .resume         = s3c_cpufreq_resume,
451         .name           = "s3c24xx",
452 };
453
454
455 int s3c_cpufreq_register(struct s3c_cpufreq_info *info)
456 {
457         if (!info || !info->name) {
458                 printk(KERN_ERR "%s: failed to pass valid information\n",
459                        __func__);
460                 return -EINVAL;
461         }
462
463         printk(KERN_INFO "S3C24XX CPU Frequency driver, %s cpu support\n",
464                info->name);
465
466         /* check our driver info has valid data */
467
468         BUG_ON(info->set_refresh == NULL);
469         BUG_ON(info->set_divs == NULL);
470         BUG_ON(info->calc_divs == NULL);
471
472         /* info->set_fvco is optional, depending on whether there
473          * is a need to set the clock code. */
474
475         cpu_cur.info = info;
476
477         /* Note, driver registering should probably update locktime */
478
479         return 0;
480 }
481
482 int __init s3c_cpufreq_setboard(struct s3c_cpufreq_board *board)
483 {
484         struct s3c_cpufreq_board *ours;
485
486         if (!board) {
487                 printk(KERN_INFO "%s: no board data\n", __func__);
488                 return -EINVAL;
489         }
490
491         /* Copy the board information so that each board can make this
492          * initdata. */
493
494         ours = kzalloc(sizeof(*ours), GFP_KERNEL);
495         if (ours == NULL) {
496                 printk(KERN_ERR "%s: no memory\n", __func__);
497                 return -ENOMEM;
498         }
499
500         *ours = *board;
501         cpu_cur.board = ours;
502
503         return 0;
504 }
505
506 static int __init s3c_cpufreq_auto_io(void)
507 {
508         int ret;
509
510         if (!cpu_cur.info->get_iotiming) {
511                 printk(KERN_ERR "%s: get_iotiming undefined\n", __func__);
512                 return -ENOENT;
513         }
514
515         printk(KERN_INFO "%s: working out IO settings\n", __func__);
516
517         ret = (cpu_cur.info->get_iotiming)(&cpu_cur, &s3c24xx_iotiming);
518         if (ret)
519                 printk(KERN_ERR "%s: failed to get timings\n", __func__);
520
521         return ret;
522 }
523
524 /* if one or is zero, then return the other, otherwise return the min */
525 #define do_min(_a, _b) ((_a) == 0 ? (_b) : (_b) == 0 ? (_a) : min(_a, _b))
526
527 /**
528  * s3c_cpufreq_freq_min - find the minimum settings for the given freq.
529  * @dst: The destination structure
530  * @a: One argument.
531  * @b: The other argument.
532  *
533  * Create a minimum of each frequency entry in the 'struct s3c_freq',
534  * unless the entry is zero when it is ignored and the non-zero argument
535  * used.
536  */
537 static void s3c_cpufreq_freq_min(struct s3c_freq *dst,
538                                  struct s3c_freq *a, struct s3c_freq *b)
539 {
540         dst->fclk = do_min(a->fclk, b->fclk);
541         dst->hclk = do_min(a->hclk, b->hclk);
542         dst->pclk = do_min(a->pclk, b->pclk);
543         dst->armclk = do_min(a->armclk, b->armclk);
544 }
545
546 static inline u32 calc_locktime(u32 freq, u32 time_us)
547 {
548         u32 result;
549
550         result = freq * time_us;
551         result = DIV_ROUND_UP(result, 1000 * 1000);
552
553         return result;
554 }
555
556 static void s3c_cpufreq_update_loctkime(void)
557 {
558         unsigned int bits = cpu_cur.info->locktime_bits;
559         u32 rate = (u32)clk_get_rate(_clk_xtal);
560         u32 val;
561
562         if (bits == 0) {
563                 WARN_ON(1);
564                 return;
565         }
566
567         val = calc_locktime(rate, cpu_cur.info->locktime_u) << bits;
568         val |= calc_locktime(rate, cpu_cur.info->locktime_m);
569
570         printk(KERN_INFO "%s: new locktime is 0x%08x\n", __func__, val);
571         __raw_writel(val, S3C2410_LOCKTIME);
572 }
573
574 static int s3c_cpufreq_build_freq(void)
575 {
576         int size, ret;
577
578         if (!cpu_cur.info->calc_freqtable)
579                 return -EINVAL;
580
581         kfree(ftab);
582         ftab = NULL;
583
584         size = cpu_cur.info->calc_freqtable(&cpu_cur, NULL, 0);
585         size++;
586
587         ftab = kzalloc(sizeof(*ftab) * size, GFP_KERNEL);
588         if (!ftab) {
589                 printk(KERN_ERR "%s: no memory for tables\n", __func__);
590                 return -ENOMEM;
591         }
592
593         ftab_size = size;
594
595         ret = cpu_cur.info->calc_freqtable(&cpu_cur, ftab, size);
596         s3c_cpufreq_addfreq(ftab, ret, size, CPUFREQ_TABLE_END);
597
598         return 0;
599 }
600
601 static int __init s3c_cpufreq_initcall(void)
602 {
603         int ret = 0;
604
605         if (cpu_cur.info && cpu_cur.board) {
606                 ret = s3c_cpufreq_initclks();
607                 if (ret)
608                         goto out;
609
610                 /* get current settings */
611                 s3c_cpufreq_getcur(&cpu_cur);
612                 s3c_cpufreq_show("cur", &cpu_cur);
613
614                 if (cpu_cur.board->auto_io) {
615                         ret = s3c_cpufreq_auto_io();
616                         if (ret) {
617                                 printk(KERN_ERR "%s: failed to get io timing\n",
618                                        __func__);
619                                 goto out;
620                         }
621                 }
622
623                 if (cpu_cur.board->need_io && !cpu_cur.info->set_iotiming) {
624                         printk(KERN_ERR "%s: no IO support registered\n",
625                                __func__);
626                         ret = -EINVAL;
627                         goto out;
628                 }
629
630                 if (!cpu_cur.info->need_pll)
631                         cpu_cur.lock_pll = 1;
632
633                 s3c_cpufreq_update_loctkime();
634
635                 s3c_cpufreq_freq_min(&cpu_cur.max, &cpu_cur.board->max,
636                                      &cpu_cur.info->max);
637
638                 if (cpu_cur.info->calc_freqtable)
639                         s3c_cpufreq_build_freq();
640
641                 ret = cpufreq_register_driver(&s3c24xx_driver);
642         }
643
644  out:
645         return ret;
646 }
647
648 late_initcall(s3c_cpufreq_initcall);
649
650 /**
651  * s3c_plltab_register - register CPU PLL table.
652  * @plls: The list of PLL entries.
653  * @plls_no: The size of the PLL entries @plls.
654  *
655  * Register the given set of PLLs with the system.
656  */
657 int s3c_plltab_register(struct cpufreq_frequency_table *plls,
658                                unsigned int plls_no)
659 {
660         struct cpufreq_frequency_table *vals;
661         unsigned int size;
662
663         size = sizeof(*vals) * (plls_no + 1);
664
665         vals = kzalloc(size, GFP_KERNEL);
666         if (vals) {
667                 memcpy(vals, plls, size);
668                 pll_reg = vals;
669
670                 /* write a terminating entry, we don't store it in the
671                  * table that is stored in the kernel */
672                 vals += plls_no;
673                 vals->frequency = CPUFREQ_TABLE_END;
674
675                 printk(KERN_INFO "cpufreq: %d PLL entries\n", plls_no);
676         } else
677                 printk(KERN_ERR "cpufreq: no memory for PLL tables\n");
678
679         return vals ? 0 : -ENOMEM;
680 }