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