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
36static struct cpufreq_driver s3c24xx_driver;
37static struct s3c_cpufreq_config cpu_cur;
38static struct s3c_iotimings s3c24xx_iotiming;
39static struct cpufreq_frequency_table *pll_reg;
40static unsigned int last_target = ~0;
41static unsigned int ftab_size;
42static struct cpufreq_frequency_table *ftab;
43
44static struct clk *_clk_mpll;
45static struct clk *_clk_xtal;
46static struct clk *clk_fclk;
47static struct clk *clk_hclk;
48static struct clk *clk_pclk;
49static struct clk *clk_arm;
50
51#ifdef CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS
52struct s3c_cpufreq_config *s3c_cpufreq_getconfig(void)
53{
54	return &cpu_cur;
55}
56
57struct s3c_iotimings *s3c_cpufreq_getiotimings(void)
58{
59	return &s3c24xx_iotiming;
60}
61#endif /* CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS */
62
63static 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
81static 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
93static 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
101static 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
112static 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
118static 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
126static void s3c_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
127{
128	(cfg->info->set_refresh)(cfg);
129}
130
131static void s3c_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
132{
133	(cfg->info->set_divs)(cfg);
134}
135
136static int s3c_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
137{
138	return (cfg->info->calc_divs)(cfg);
139}
140
141static void s3c_cpufreq_setfvco(struct s3c_cpufreq_config *cfg)
142{
143	cfg->mpll = _clk_mpll;
144	(cfg->info->set_fvco)(cfg);
145}
146
147static inline void s3c_cpufreq_updateclk(struct clk *clk,
148					 unsigned int freq)
149{
150	clk_set_rate(clk, freq);
151}
152
153static 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
275static 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
353struct 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
364static int s3c_cpufreq_init(struct cpufreq_policy *policy)
365{
366	policy->clk = clk_arm;
367	return cpufreq_generic_init(policy, ftab, cpu_cur.info->latency);
368}
369
370static int __init s3c_cpufreq_initclks(void)
371{
372	_clk_mpll = s3c_cpufreq_clk_get(NULL, "mpll");
373	_clk_xtal = s3c_cpufreq_clk_get(NULL, "xtal");
374	clk_fclk = s3c_cpufreq_clk_get(NULL, "fclk");
375	clk_hclk = s3c_cpufreq_clk_get(NULL, "hclk");
376	clk_pclk = s3c_cpufreq_clk_get(NULL, "pclk");
377	clk_arm = s3c_cpufreq_clk_get(NULL, "armclk");
378
379	if (IS_ERR(clk_fclk) || IS_ERR(clk_hclk) || IS_ERR(clk_pclk) ||
380	    IS_ERR(_clk_mpll) || IS_ERR(clk_arm) || IS_ERR(_clk_xtal)) {
381		printk(KERN_ERR "%s: could not get clock(s)\n", __func__);
382		return -ENOENT;
383	}
384
385	printk(KERN_INFO "%s: clocks f=%lu,h=%lu,p=%lu,a=%lu\n", __func__,
386	       clk_get_rate(clk_fclk) / 1000,
387	       clk_get_rate(clk_hclk) / 1000,
388	       clk_get_rate(clk_pclk) / 1000,
389	       clk_get_rate(clk_arm) / 1000);
390
391	return 0;
392}
393
394#ifdef CONFIG_PM
395static struct cpufreq_frequency_table suspend_pll;
396static unsigned int suspend_freq;
397
398static int s3c_cpufreq_suspend(struct cpufreq_policy *policy)
399{
400	suspend_pll.frequency = clk_get_rate(_clk_mpll);
401	suspend_pll.driver_data = __raw_readl(S3C2410_MPLLCON);
402	suspend_freq = clk_get_rate(clk_arm);
403
404	return 0;
405}
406
407static int s3c_cpufreq_resume(struct cpufreq_policy *policy)
408{
409	int ret;
410
411	s3c_freq_dbg("%s: resuming with policy %p\n", __func__, policy);
412
413	last_target = ~0;	/* invalidate last_target setting */
414
415	/* whilst we will be called later on, we try and re-set the
416	 * cpu frequencies as soon as possible so that we do not end
417	 * up resuming devices and then immediately having to re-set
418	 * a number of settings once these devices have restarted.
419	 *
420	 * as a note, it is expected devices are not used until they
421	 * have been un-suspended and at that time they should have
422	 * used the updated clock settings.
423	 */
424
425	ret = s3c_cpufreq_settarget(NULL, suspend_freq, &suspend_pll);
426	if (ret) {
427		printk(KERN_ERR "%s: failed to reset pll/freq\n", __func__);
428		return ret;
429	}
430
431	return 0;
432}
433#else
434#define s3c_cpufreq_resume NULL
435#define s3c_cpufreq_suspend NULL
436#endif
437
438static struct cpufreq_driver s3c24xx_driver = {
439	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
440	.target		= s3c_cpufreq_target,
441	.get		= cpufreq_generic_get,
442	.init		= s3c_cpufreq_init,
443	.suspend	= s3c_cpufreq_suspend,
444	.resume		= s3c_cpufreq_resume,
445	.name		= "s3c24xx",
446};
447
448
449int s3c_cpufreq_register(struct s3c_cpufreq_info *info)
450{
451	if (!info || !info->name) {
452		printk(KERN_ERR "%s: failed to pass valid information\n",
453		       __func__);
454		return -EINVAL;
455	}
456
457	printk(KERN_INFO "S3C24XX CPU Frequency driver, %s cpu support\n",
458	       info->name);
459
460	/* check our driver info has valid data */
461
462	BUG_ON(info->set_refresh == NULL);
463	BUG_ON(info->set_divs == NULL);
464	BUG_ON(info->calc_divs == NULL);
465
466	/* info->set_fvco is optional, depending on whether there
467	 * is a need to set the clock code. */
468
469	cpu_cur.info = info;
470
471	/* Note, driver registering should probably update locktime */
472
473	return 0;
474}
475
476int __init s3c_cpufreq_setboard(struct s3c_cpufreq_board *board)
477{
478	struct s3c_cpufreq_board *ours;
479
480	if (!board) {
481		printk(KERN_INFO "%s: no board data\n", __func__);
482		return -EINVAL;
483	}
484
485	/* Copy the board information so that each board can make this
486	 * initdata. */
487
488	ours = kzalloc(sizeof(*ours), GFP_KERNEL);
489	if (ours == NULL) {
490		printk(KERN_ERR "%s: no memory\n", __func__);
491		return -ENOMEM;
492	}
493
494	*ours = *board;
495	cpu_cur.board = ours;
496
497	return 0;
498}
499
500static int __init s3c_cpufreq_auto_io(void)
501{
502	int ret;
503
504	if (!cpu_cur.info->get_iotiming) {
505		printk(KERN_ERR "%s: get_iotiming undefined\n", __func__);
506		return -ENOENT;
507	}
508
509	printk(KERN_INFO "%s: working out IO settings\n", __func__);
510
511	ret = (cpu_cur.info->get_iotiming)(&cpu_cur, &s3c24xx_iotiming);
512	if (ret)
513		printk(KERN_ERR "%s: failed to get timings\n", __func__);
514
515	return ret;
516}
517
518/* if one or is zero, then return the other, otherwise return the min */
519#define do_min(_a, _b) ((_a) == 0 ? (_b) : (_b) == 0 ? (_a) : min(_a, _b))
520
521/**
522 * s3c_cpufreq_freq_min - find the minimum settings for the given freq.
523 * @dst: The destination structure
524 * @a: One argument.
525 * @b: The other argument.
526 *
527 * Create a minimum of each frequency entry in the 'struct s3c_freq',
528 * unless the entry is zero when it is ignored and the non-zero argument
529 * used.
530 */
531static void s3c_cpufreq_freq_min(struct s3c_freq *dst,
532				 struct s3c_freq *a, struct s3c_freq *b)
533{
534	dst->fclk = do_min(a->fclk, b->fclk);
535	dst->hclk = do_min(a->hclk, b->hclk);
536	dst->pclk = do_min(a->pclk, b->pclk);
537	dst->armclk = do_min(a->armclk, b->armclk);
538}
539
540static inline u32 calc_locktime(u32 freq, u32 time_us)
541{
542	u32 result;
543
544	result = freq * time_us;
545	result = DIV_ROUND_UP(result, 1000 * 1000);
546
547	return result;
548}
549
550static void s3c_cpufreq_update_loctkime(void)
551{
552	unsigned int bits = cpu_cur.info->locktime_bits;
553	u32 rate = (u32)clk_get_rate(_clk_xtal);
554	u32 val;
555
556	if (bits == 0) {
557		WARN_ON(1);
558		return;
559	}
560
561	val = calc_locktime(rate, cpu_cur.info->locktime_u) << bits;
562	val |= calc_locktime(rate, cpu_cur.info->locktime_m);
563
564	printk(KERN_INFO "%s: new locktime is 0x%08x\n", __func__, val);
565	__raw_writel(val, S3C2410_LOCKTIME);
566}
567
568static int s3c_cpufreq_build_freq(void)
569{
570	int size, ret;
571
572	if (!cpu_cur.info->calc_freqtable)
573		return -EINVAL;
574
575	kfree(ftab);
576	ftab = NULL;
577
578	size = cpu_cur.info->calc_freqtable(&cpu_cur, NULL, 0);
579	size++;
580
581	ftab = kzalloc(sizeof(*ftab) * size, GFP_KERNEL);
582	if (!ftab) {
583		printk(KERN_ERR "%s: no memory for tables\n", __func__);
584		return -ENOMEM;
585	}
586
587	ftab_size = size;
588
589	ret = cpu_cur.info->calc_freqtable(&cpu_cur, ftab, size);
590	s3c_cpufreq_addfreq(ftab, ret, size, CPUFREQ_TABLE_END);
591
592	return 0;
593}
594
595static int __init s3c_cpufreq_initcall(void)
596{
597	int ret = 0;
598
599	if (cpu_cur.info && cpu_cur.board) {
600		ret = s3c_cpufreq_initclks();
601		if (ret)
602			goto out;
603
604		/* get current settings */
605		s3c_cpufreq_getcur(&cpu_cur);
606		s3c_cpufreq_show("cur", &cpu_cur);
607
608		if (cpu_cur.board->auto_io) {
609			ret = s3c_cpufreq_auto_io();
610			if (ret) {
611				printk(KERN_ERR "%s: failed to get io timing\n",
612				       __func__);
613				goto out;
614			}
615		}
616
617		if (cpu_cur.board->need_io && !cpu_cur.info->set_iotiming) {
618			printk(KERN_ERR "%s: no IO support registered\n",
619			       __func__);
620			ret = -EINVAL;
621			goto out;
622		}
623
624		if (!cpu_cur.info->need_pll)
625			cpu_cur.lock_pll = 1;
626
627		s3c_cpufreq_update_loctkime();
628
629		s3c_cpufreq_freq_min(&cpu_cur.max, &cpu_cur.board->max,
630				     &cpu_cur.info->max);
631
632		if (cpu_cur.info->calc_freqtable)
633			s3c_cpufreq_build_freq();
634
635		ret = cpufreq_register_driver(&s3c24xx_driver);
636	}
637
638 out:
639	return ret;
640}
641
642late_initcall(s3c_cpufreq_initcall);
643
644/**
645 * s3c_plltab_register - register CPU PLL table.
646 * @plls: The list of PLL entries.
647 * @plls_no: The size of the PLL entries @plls.
648 *
649 * Register the given set of PLLs with the system.
650 */
651int s3c_plltab_register(struct cpufreq_frequency_table *plls,
652			       unsigned int plls_no)
653{
654	struct cpufreq_frequency_table *vals;
655	unsigned int size;
656
657	size = sizeof(*vals) * (plls_no + 1);
658
659	vals = kzalloc(size, GFP_KERNEL);
660	if (vals) {
661		memcpy(vals, plls, size);
662		pll_reg = vals;
663
664		/* write a terminating entry, we don't store it in the
665		 * table that is stored in the kernel */
666		vals += plls_no;
667		vals->frequency = CPUFREQ_TABLE_END;
668
669		printk(KERN_INFO "cpufreq: %d PLL entries\n", plls_no);
670	} else
671		printk(KERN_ERR "cpufreq: no memory for PLL tables\n");
672
673	return vals ? 0 : -ENOMEM;
674}
675