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[karo-tx-linux.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/clock.h>
31 #include <plat/cpu-freq-core.h>
32
33 #include <mach/regs-clock.h>
34
35 /* note, cpufreq support deals in kHz, no Hz */
36
37 static struct cpufreq_driver s3c24xx_driver;
38 static struct s3c_cpufreq_config cpu_cur;
39 static struct s3c_iotimings s3c24xx_iotiming;
40 static struct cpufreq_frequency_table *pll_reg;
41 static unsigned int last_target = ~0;
42 static unsigned int ftab_size;
43 static struct cpufreq_frequency_table *ftab;
44
45 static struct clk *_clk_mpll;
46 static struct clk *_clk_xtal;
47 static struct clk *clk_fclk;
48 static struct clk *clk_hclk;
49 static struct clk *clk_pclk;
50 static struct clk *clk_arm;
51
52 #ifdef CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS
53 struct s3c_cpufreq_config *s3c_cpufreq_getconfig(void)
54 {
55         return &cpu_cur;
56 }
57
58 struct s3c_iotimings *s3c_cpufreq_getiotimings(void)
59 {
60         return &s3c24xx_iotiming;
61 }
62 #endif /* CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS */
63
64 static void s3c_cpufreq_getcur(struct s3c_cpufreq_config *cfg)
65 {
66         unsigned long fclk, pclk, hclk, armclk;
67
68         cfg->freq.fclk = fclk = clk_get_rate(clk_fclk);
69         cfg->freq.hclk = hclk = clk_get_rate(clk_hclk);
70         cfg->freq.pclk = pclk = clk_get_rate(clk_pclk);
71         cfg->freq.armclk = armclk = clk_get_rate(clk_arm);
72
73         cfg->pll.driver_data = __raw_readl(S3C2410_MPLLCON);
74         cfg->pll.frequency = fclk;
75
76         cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10);
77
78         cfg->divs.h_divisor = fclk / hclk;
79         cfg->divs.p_divisor = fclk / pclk;
80 }
81
82 static inline void s3c_cpufreq_calc(struct s3c_cpufreq_config *cfg)
83 {
84         unsigned long pll = cfg->pll.frequency;
85
86         cfg->freq.fclk = pll;
87         cfg->freq.hclk = pll / cfg->divs.h_divisor;
88         cfg->freq.pclk = pll / cfg->divs.p_divisor;
89
90         /* convert hclk into 10ths of nanoseconds for io calcs */
91         cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10);
92 }
93
94 static inline int closer(unsigned int target, unsigned int n, unsigned int c)
95 {
96         int diff_cur = abs(target - c);
97         int diff_new = abs(target - n);
98
99         return (diff_new < diff_cur);
100 }
101
102 static void s3c_cpufreq_show(const char *pfx,
103                                  struct s3c_cpufreq_config *cfg)
104 {
105         s3c_freq_dbg("%s: Fvco=%u, F=%lu, A=%lu, H=%lu (%u), P=%lu (%u)\n",
106                      pfx, cfg->pll.frequency, cfg->freq.fclk, cfg->freq.armclk,
107                      cfg->freq.hclk, cfg->divs.h_divisor,
108                      cfg->freq.pclk, cfg->divs.p_divisor);
109 }
110
111 /* functions to wrapper the driver info calls to do the cpu specific work */
112
113 static void s3c_cpufreq_setio(struct s3c_cpufreq_config *cfg)
114 {
115         if (cfg->info->set_iotiming)
116                 (cfg->info->set_iotiming)(cfg, &s3c24xx_iotiming);
117 }
118
119 static int s3c_cpufreq_calcio(struct s3c_cpufreq_config *cfg)
120 {
121         if (cfg->info->calc_iotiming)
122                 return (cfg->info->calc_iotiming)(cfg, &s3c24xx_iotiming);
123
124         return 0;
125 }
126
127 static void s3c_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
128 {
129         (cfg->info->set_refresh)(cfg);
130 }
131
132 static void s3c_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
133 {
134         (cfg->info->set_divs)(cfg);
135 }
136
137 static int s3c_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
138 {
139         return (cfg->info->calc_divs)(cfg);
140 }
141
142 static void s3c_cpufreq_setfvco(struct s3c_cpufreq_config *cfg)
143 {
144         (cfg->info->set_fvco)(cfg);
145 }
146
147 static inline void s3c_cpufreq_resume_clocks(void)
148 {
149         cpu_cur.info->resume_clocks();
150 }
151
152 static inline void s3c_cpufreq_updateclk(struct clk *clk,
153                                          unsigned int freq)
154 {
155         clk_set_rate(clk, freq);
156 }
157
158 static int s3c_cpufreq_settarget(struct cpufreq_policy *policy,
159                                  unsigned int target_freq,
160                                  struct cpufreq_frequency_table *pll)
161 {
162         struct s3c_cpufreq_freqs freqs;
163         struct s3c_cpufreq_config cpu_new;
164         unsigned long flags;
165
166         cpu_new = cpu_cur;  /* copy new from current */
167
168         s3c_cpufreq_show("cur", &cpu_cur);
169
170         /* TODO - check for DMA currently outstanding */
171
172         cpu_new.pll = pll ? *pll : cpu_cur.pll;
173
174         if (pll)
175                 freqs.pll_changing = 1;
176
177         /* update our frequencies */
178
179         cpu_new.freq.armclk = target_freq;
180         cpu_new.freq.fclk = cpu_new.pll.frequency;
181
182         if (s3c_cpufreq_calcdivs(&cpu_new) < 0) {
183                 printk(KERN_ERR "no divisors for %d\n", target_freq);
184                 goto err_notpossible;
185         }
186
187         s3c_freq_dbg("%s: got divs\n", __func__);
188
189         s3c_cpufreq_calc(&cpu_new);
190
191         s3c_freq_dbg("%s: calculated frequencies for new\n", __func__);
192
193         if (cpu_new.freq.hclk != cpu_cur.freq.hclk) {
194                 if (s3c_cpufreq_calcio(&cpu_new) < 0) {
195                         printk(KERN_ERR "%s: no IO timings\n", __func__);
196                         goto err_notpossible;
197                 }
198         }
199
200         s3c_cpufreq_show("new", &cpu_new);
201
202         /* setup our cpufreq parameters */
203
204         freqs.old = cpu_cur.freq;
205         freqs.new = cpu_new.freq;
206
207         freqs.freqs.old = cpu_cur.freq.armclk / 1000;
208         freqs.freqs.new = cpu_new.freq.armclk / 1000;
209
210         /* update f/h/p clock settings before we issue the change
211          * notification, so that drivers do not need to do anything
212          * special if they want to recalculate on CPUFREQ_PRECHANGE. */
213
214         s3c_cpufreq_updateclk(_clk_mpll, cpu_new.pll.frequency);
215         s3c_cpufreq_updateclk(clk_fclk, cpu_new.freq.fclk);
216         s3c_cpufreq_updateclk(clk_hclk, cpu_new.freq.hclk);
217         s3c_cpufreq_updateclk(clk_pclk, cpu_new.freq.pclk);
218
219         /* start the frequency change */
220         cpufreq_notify_transition(policy, &freqs.freqs, CPUFREQ_PRECHANGE);
221
222         /* If hclk is staying the same, then we do not need to
223          * re-write the IO or the refresh timings whilst we are changing
224          * speed. */
225
226         local_irq_save(flags);
227
228         /* is our memory clock slowing down? */
229         if (cpu_new.freq.hclk < cpu_cur.freq.hclk) {
230                 s3c_cpufreq_setrefresh(&cpu_new);
231                 s3c_cpufreq_setio(&cpu_new);
232         }
233
234         if (cpu_new.freq.fclk == cpu_cur.freq.fclk) {
235                 /* not changing PLL, just set the divisors */
236
237                 s3c_cpufreq_setdivs(&cpu_new);
238         } else {
239                 if (cpu_new.freq.fclk < cpu_cur.freq.fclk) {
240                         /* slow the cpu down, then set divisors */
241
242                         s3c_cpufreq_setfvco(&cpu_new);
243                         s3c_cpufreq_setdivs(&cpu_new);
244                 } else {
245                         /* set the divisors, then speed up */
246
247                         s3c_cpufreq_setdivs(&cpu_new);
248                         s3c_cpufreq_setfvco(&cpu_new);
249                 }
250         }
251
252         /* did our memory clock speed up */
253         if (cpu_new.freq.hclk > cpu_cur.freq.hclk) {
254                 s3c_cpufreq_setrefresh(&cpu_new);
255                 s3c_cpufreq_setio(&cpu_new);
256         }
257
258         /* update our current settings */
259         cpu_cur = cpu_new;
260
261         local_irq_restore(flags);
262
263         /* notify everyone we've done this */
264         cpufreq_notify_transition(policy, &freqs.freqs, CPUFREQ_POSTCHANGE);
265
266         s3c_freq_dbg("%s: finished\n", __func__);
267         return 0;
268
269  err_notpossible:
270         printk(KERN_ERR "no compatible settings for %d\n", target_freq);
271         return -EINVAL;
272 }
273
274 /* s3c_cpufreq_target
275  *
276  * called by the cpufreq core to adjust the frequency that the CPU
277  * is currently running at.
278  */
279
280 static int s3c_cpufreq_target(struct cpufreq_policy *policy,
281                               unsigned int target_freq,
282                               unsigned int relation)
283 {
284         struct cpufreq_frequency_table *pll;
285         unsigned int index;
286
287         /* avoid repeated calls which cause a needless amout of duplicated
288          * logging output (and CPU time as the calculation process is
289          * done) */
290         if (target_freq == last_target)
291                 return 0;
292
293         last_target = target_freq;
294
295         s3c_freq_dbg("%s: policy %p, target %u, relation %u\n",
296                      __func__, policy, target_freq, relation);
297
298         if (ftab) {
299                 if (cpufreq_frequency_table_target(policy, ftab,
300                                                    target_freq, relation,
301                                                    &index)) {
302                         s3c_freq_dbg("%s: table failed\n", __func__);
303                         return -EINVAL;
304                 }
305
306                 s3c_freq_dbg("%s: adjust %d to entry %d (%u)\n", __func__,
307                              target_freq, index, ftab[index].frequency);
308                 target_freq = ftab[index].frequency;
309         }
310
311         target_freq *= 1000;  /* convert target to Hz */
312
313         /* find the settings for our new frequency */
314
315         if (!pll_reg || cpu_cur.lock_pll) {
316                 /* either we've not got any PLL values, or we've locked
317                  * to the current one. */
318                 pll = NULL;
319         } else {
320                 struct cpufreq_policy tmp_policy;
321                 int ret;
322
323                 /* we keep the cpu pll table in Hz, to ensure we get an
324                  * accurate value for the PLL output. */
325
326                 tmp_policy.min = policy->min * 1000;
327                 tmp_policy.max = policy->max * 1000;
328                 tmp_policy.cpu = policy->cpu;
329
330                 /* cpufreq_frequency_table_target uses a pointer to 'index'
331                  * which is the number of the table entry, not the value of
332                  * the table entry's index field. */
333
334                 ret = cpufreq_frequency_table_target(&tmp_policy, pll_reg,
335                                                      target_freq, relation,
336                                                      &index);
337
338                 if (ret < 0) {
339                         printk(KERN_ERR "%s: no PLL available\n", __func__);
340                         goto err_notpossible;
341                 }
342
343                 pll = pll_reg + index;
344
345                 s3c_freq_dbg("%s: target %u => %u\n",
346                              __func__, target_freq, pll->frequency);
347
348                 target_freq = pll->frequency;
349         }
350
351         return s3c_cpufreq_settarget(policy, target_freq, pll);
352
353  err_notpossible:
354         printk(KERN_ERR "no compatible settings for %d\n", target_freq);
355         return -EINVAL;
356 }
357
358 static unsigned int s3c_cpufreq_get(unsigned int cpu)
359 {
360         return clk_get_rate(clk_arm) / 1000;
361 }
362
363 struct clk *s3c_cpufreq_clk_get(struct device *dev, const char *name)
364 {
365         struct clk *clk;
366
367         clk = clk_get(dev, name);
368         if (IS_ERR(clk))
369                 printk(KERN_ERR "cpufreq: failed to get clock '%s'\n", name);
370
371         return clk;
372 }
373
374 static int s3c_cpufreq_init(struct cpufreq_policy *policy)
375 {
376         return cpufreq_generic_init(policy, ftab, cpu_cur.info->latency);
377 }
378
379 static int __init s3c_cpufreq_initclks(void)
380 {
381         _clk_mpll = s3c_cpufreq_clk_get(NULL, "mpll");
382         _clk_xtal = s3c_cpufreq_clk_get(NULL, "xtal");
383         clk_fclk = s3c_cpufreq_clk_get(NULL, "fclk");
384         clk_hclk = s3c_cpufreq_clk_get(NULL, "hclk");
385         clk_pclk = s3c_cpufreq_clk_get(NULL, "pclk");
386         clk_arm = s3c_cpufreq_clk_get(NULL, "armclk");
387
388         if (IS_ERR(clk_fclk) || IS_ERR(clk_hclk) || IS_ERR(clk_pclk) ||
389             IS_ERR(_clk_mpll) || IS_ERR(clk_arm) || IS_ERR(_clk_xtal)) {
390                 printk(KERN_ERR "%s: could not get clock(s)\n", __func__);
391                 return -ENOENT;
392         }
393
394         printk(KERN_INFO "%s: clocks f=%lu,h=%lu,p=%lu,a=%lu\n", __func__,
395                clk_get_rate(clk_fclk) / 1000,
396                clk_get_rate(clk_hclk) / 1000,
397                clk_get_rate(clk_pclk) / 1000,
398                clk_get_rate(clk_arm) / 1000);
399
400         return 0;
401 }
402
403 #ifdef CONFIG_PM
404 static struct cpufreq_frequency_table suspend_pll;
405 static unsigned int suspend_freq;
406
407 static int s3c_cpufreq_suspend(struct cpufreq_policy *policy)
408 {
409         suspend_pll.frequency = clk_get_rate(_clk_mpll);
410         suspend_pll.driver_data = __raw_readl(S3C2410_MPLLCON);
411         suspend_freq = s3c_cpufreq_get(0) * 1000;
412
413         return 0;
414 }
415
416 static int s3c_cpufreq_resume(struct cpufreq_policy *policy)
417 {
418         int ret;
419
420         s3c_freq_dbg("%s: resuming with policy %p\n", __func__, policy);
421
422         last_target = ~0;       /* invalidate last_target setting */
423
424         /* first, find out what speed we resumed at. */
425         s3c_cpufreq_resume_clocks();
426
427         /* whilst we will be called later on, we try and re-set the
428          * cpu frequencies as soon as possible so that we do not end
429          * up resuming devices and then immediately having to re-set
430          * a number of settings once these devices have restarted.
431          *
432          * as a note, it is expected devices are not used until they
433          * have been un-suspended and at that time they should have
434          * used the updated clock settings.
435          */
436
437         ret = s3c_cpufreq_settarget(NULL, suspend_freq, &suspend_pll);
438         if (ret) {
439                 printk(KERN_ERR "%s: failed to reset pll/freq\n", __func__);
440                 return ret;
441         }
442
443         return 0;
444 }
445 #else
446 #define s3c_cpufreq_resume NULL
447 #define s3c_cpufreq_suspend NULL
448 #endif
449
450 static struct cpufreq_driver s3c24xx_driver = {
451         .flags          = CPUFREQ_STICKY,
452         .target         = s3c_cpufreq_target,
453         .get            = s3c_cpufreq_get,
454         .init           = s3c_cpufreq_init,
455         .suspend        = s3c_cpufreq_suspend,
456         .resume         = s3c_cpufreq_resume,
457         .name           = "s3c24xx",
458 };
459
460
461 int __init s3c_cpufreq_register(struct s3c_cpufreq_info *info)
462 {
463         if (!info || !info->name) {
464                 printk(KERN_ERR "%s: failed to pass valid information\n",
465                        __func__);
466                 return -EINVAL;
467         }
468
469         printk(KERN_INFO "S3C24XX CPU Frequency driver, %s cpu support\n",
470                info->name);
471
472         /* check our driver info has valid data */
473
474         BUG_ON(info->set_refresh == NULL);
475         BUG_ON(info->set_divs == NULL);
476         BUG_ON(info->calc_divs == NULL);
477
478         /* info->set_fvco is optional, depending on whether there
479          * is a need to set the clock code. */
480
481         cpu_cur.info = info;
482
483         /* Note, driver registering should probably update locktime */
484
485         return 0;
486 }
487
488 int __init s3c_cpufreq_setboard(struct s3c_cpufreq_board *board)
489 {
490         struct s3c_cpufreq_board *ours;
491
492         if (!board) {
493                 printk(KERN_INFO "%s: no board data\n", __func__);
494                 return -EINVAL;
495         }
496
497         /* Copy the board information so that each board can make this
498          * initdata. */
499
500         ours = kzalloc(sizeof(*ours), GFP_KERNEL);
501         if (ours == NULL) {
502                 printk(KERN_ERR "%s: no memory\n", __func__);
503                 return -ENOMEM;
504         }
505
506         *ours = *board;
507         cpu_cur.board = ours;
508
509         return 0;
510 }
511
512 int __init s3c_cpufreq_auto_io(void)
513 {
514         int ret;
515
516         if (!cpu_cur.info->get_iotiming) {
517                 printk(KERN_ERR "%s: get_iotiming undefined\n", __func__);
518                 return -ENOENT;
519         }
520
521         printk(KERN_INFO "%s: working out IO settings\n", __func__);
522
523         ret = (cpu_cur.info->get_iotiming)(&cpu_cur, &s3c24xx_iotiming);
524         if (ret)
525                 printk(KERN_ERR "%s: failed to get timings\n", __func__);
526
527         return ret;
528 }
529
530 /* if one or is zero, then return the other, otherwise return the min */
531 #define do_min(_a, _b) ((_a) == 0 ? (_b) : (_b) == 0 ? (_a) : min(_a, _b))
532
533 /**
534  * s3c_cpufreq_freq_min - find the minimum settings for the given freq.
535  * @dst: The destination structure
536  * @a: One argument.
537  * @b: The other argument.
538  *
539  * Create a minimum of each frequency entry in the 'struct s3c_freq',
540  * unless the entry is zero when it is ignored and the non-zero argument
541  * used.
542  */
543 static void s3c_cpufreq_freq_min(struct s3c_freq *dst,
544                                  struct s3c_freq *a, struct s3c_freq *b)
545 {
546         dst->fclk = do_min(a->fclk, b->fclk);
547         dst->hclk = do_min(a->hclk, b->hclk);
548         dst->pclk = do_min(a->pclk, b->pclk);
549         dst->armclk = do_min(a->armclk, b->armclk);
550 }
551
552 static inline u32 calc_locktime(u32 freq, u32 time_us)
553 {
554         u32 result;
555
556         result = freq * time_us;
557         result = DIV_ROUND_UP(result, 1000 * 1000);
558
559         return result;
560 }
561
562 static void s3c_cpufreq_update_loctkime(void)
563 {
564         unsigned int bits = cpu_cur.info->locktime_bits;
565         u32 rate = (u32)clk_get_rate(_clk_xtal);
566         u32 val;
567
568         if (bits == 0) {
569                 WARN_ON(1);
570                 return;
571         }
572
573         val = calc_locktime(rate, cpu_cur.info->locktime_u) << bits;
574         val |= calc_locktime(rate, cpu_cur.info->locktime_m);
575
576         printk(KERN_INFO "%s: new locktime is 0x%08x\n", __func__, val);
577         __raw_writel(val, S3C2410_LOCKTIME);
578 }
579
580 static int s3c_cpufreq_build_freq(void)
581 {
582         int size, ret;
583
584         if (!cpu_cur.info->calc_freqtable)
585                 return -EINVAL;
586
587         kfree(ftab);
588         ftab = NULL;
589
590         size = cpu_cur.info->calc_freqtable(&cpu_cur, NULL, 0);
591         size++;
592
593         ftab = kmalloc(sizeof(*ftab) * size, GFP_KERNEL);
594         if (!ftab) {
595                 printk(KERN_ERR "%s: no memory for tables\n", __func__);
596                 return -ENOMEM;
597         }
598
599         ftab_size = size;
600
601         ret = cpu_cur.info->calc_freqtable(&cpu_cur, ftab, size);
602         s3c_cpufreq_addfreq(ftab, ret, size, CPUFREQ_TABLE_END);
603
604         return 0;
605 }
606
607 static int __init s3c_cpufreq_initcall(void)
608 {
609         int ret = 0;
610
611         if (cpu_cur.info && cpu_cur.board) {
612                 ret = s3c_cpufreq_initclks();
613                 if (ret)
614                         goto out;
615
616                 /* get current settings */
617                 s3c_cpufreq_getcur(&cpu_cur);
618                 s3c_cpufreq_show("cur", &cpu_cur);
619
620                 if (cpu_cur.board->auto_io) {
621                         ret = s3c_cpufreq_auto_io();
622                         if (ret) {
623                                 printk(KERN_ERR "%s: failed to get io timing\n",
624                                        __func__);
625                                 goto out;
626                         }
627                 }
628
629                 if (cpu_cur.board->need_io && !cpu_cur.info->set_iotiming) {
630                         printk(KERN_ERR "%s: no IO support registered\n",
631                                __func__);
632                         ret = -EINVAL;
633                         goto out;
634                 }
635
636                 if (!cpu_cur.info->need_pll)
637                         cpu_cur.lock_pll = 1;
638
639                 s3c_cpufreq_update_loctkime();
640
641                 s3c_cpufreq_freq_min(&cpu_cur.max, &cpu_cur.board->max,
642                                      &cpu_cur.info->max);
643
644                 if (cpu_cur.info->calc_freqtable)
645                         s3c_cpufreq_build_freq();
646
647                 ret = cpufreq_register_driver(&s3c24xx_driver);
648         }
649
650  out:
651         return ret;
652 }
653
654 late_initcall(s3c_cpufreq_initcall);
655
656 /**
657  * s3c_plltab_register - register CPU PLL table.
658  * @plls: The list of PLL entries.
659  * @plls_no: The size of the PLL entries @plls.
660  *
661  * Register the given set of PLLs with the system.
662  */
663 int __init s3c_plltab_register(struct cpufreq_frequency_table *plls,
664                                unsigned int plls_no)
665 {
666         struct cpufreq_frequency_table *vals;
667         unsigned int size;
668
669         size = sizeof(*vals) * (plls_no + 1);
670
671         vals = kmalloc(size, GFP_KERNEL);
672         if (vals) {
673                 memcpy(vals, plls, size);
674                 pll_reg = vals;
675
676                 /* write a terminating entry, we don't store it in the
677                  * table that is stored in the kernel */
678                 vals += plls_no;
679                 vals->frequency = CPUFREQ_TABLE_END;
680
681                 printk(KERN_INFO "cpufreq: %d PLL entries\n", plls_no);
682         } else
683                 printk(KERN_ERR "cpufreq: no memory for PLL tables\n");
684
685         return vals ? 0 : -ENOMEM;
686 }