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34ee5507 HS |
1 | /* |
2 | * S3C2416/2450 CPUfreq Support | |
3 | * | |
4 | * Copyright 2011 Heiko Stuebner <heiko@sntech.de> | |
5 | * | |
6 | * based on s3c64xx_cpufreq.c | |
7 | * | |
8 | * Copyright 2009 Wolfson Microelectronics plc | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | */ | |
14 | ||
15 | #include <linux/kernel.h> | |
16 | #include <linux/types.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/cpufreq.h> | |
19 | #include <linux/clk.h> | |
20 | #include <linux/err.h> | |
21 | #include <linux/regulator/consumer.h> | |
22 | #include <linux/reboot.h> | |
23 | #include <linux/module.h> | |
24 | ||
25 | static DEFINE_MUTEX(cpufreq_lock); | |
26 | ||
27 | struct s3c2416_data { | |
28 | struct clk *armdiv; | |
29 | struct clk *armclk; | |
30 | struct clk *hclk; | |
31 | ||
32 | unsigned long regulator_latency; | |
33 | #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE | |
34 | struct regulator *vddarm; | |
35 | #endif | |
36 | ||
37 | struct cpufreq_frequency_table *freq_table; | |
38 | ||
39 | bool is_dvs; | |
40 | bool disable_dvs; | |
41 | }; | |
42 | ||
43 | static struct s3c2416_data s3c2416_cpufreq; | |
44 | ||
45 | struct s3c2416_dvfs { | |
46 | unsigned int vddarm_min; | |
47 | unsigned int vddarm_max; | |
48 | }; | |
49 | ||
50 | /* pseudo-frequency for dvs mode */ | |
51 | #define FREQ_DVS 132333 | |
52 | ||
53 | /* frequency to sleep and reboot in | |
54 | * it's essential to leave dvs, as some boards do not reconfigure the | |
55 | * regulator on reboot | |
56 | */ | |
57 | #define FREQ_SLEEP 133333 | |
58 | ||
59 | /* Sources for the ARMCLK */ | |
60 | #define SOURCE_HCLK 0 | |
61 | #define SOURCE_ARMDIV 1 | |
62 | ||
63 | #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE | |
64 | /* S3C2416 only supports changing the voltage in the dvs-mode. | |
65 | * Voltages down to 1.0V seem to work, so we take what the regulator | |
66 | * can get us. | |
67 | */ | |
68 | static struct s3c2416_dvfs s3c2416_dvfs_table[] = { | |
69 | [SOURCE_HCLK] = { 950000, 1250000 }, | |
70 | [SOURCE_ARMDIV] = { 1250000, 1350000 }, | |
71 | }; | |
72 | #endif | |
73 | ||
74 | static struct cpufreq_frequency_table s3c2416_freq_table[] = { | |
75 | { SOURCE_HCLK, FREQ_DVS }, | |
76 | { SOURCE_ARMDIV, 133333 }, | |
77 | { SOURCE_ARMDIV, 266666 }, | |
78 | { SOURCE_ARMDIV, 400000 }, | |
79 | { 0, CPUFREQ_TABLE_END }, | |
80 | }; | |
81 | ||
82 | static struct cpufreq_frequency_table s3c2450_freq_table[] = { | |
83 | { SOURCE_HCLK, FREQ_DVS }, | |
84 | { SOURCE_ARMDIV, 133500 }, | |
85 | { SOURCE_ARMDIV, 267000 }, | |
86 | { SOURCE_ARMDIV, 534000 }, | |
87 | { 0, CPUFREQ_TABLE_END }, | |
88 | }; | |
89 | ||
90 | static int s3c2416_cpufreq_verify_speed(struct cpufreq_policy *policy) | |
91 | { | |
92 | struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; | |
93 | ||
94 | if (policy->cpu != 0) | |
95 | return -EINVAL; | |
96 | ||
97 | return cpufreq_frequency_table_verify(policy, s3c_freq->freq_table); | |
98 | } | |
99 | ||
100 | static unsigned int s3c2416_cpufreq_get_speed(unsigned int cpu) | |
101 | { | |
102 | struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; | |
103 | ||
104 | if (cpu != 0) | |
105 | return 0; | |
106 | ||
107 | /* return our pseudo-frequency when in dvs mode */ | |
108 | if (s3c_freq->is_dvs) | |
109 | return FREQ_DVS; | |
110 | ||
111 | return clk_get_rate(s3c_freq->armclk) / 1000; | |
112 | } | |
113 | ||
114 | static int s3c2416_cpufreq_set_armdiv(struct s3c2416_data *s3c_freq, | |
115 | unsigned int freq) | |
116 | { | |
117 | int ret; | |
118 | ||
119 | if (clk_get_rate(s3c_freq->armdiv) / 1000 != freq) { | |
120 | ret = clk_set_rate(s3c_freq->armdiv, freq * 1000); | |
121 | if (ret < 0) { | |
122 | pr_err("cpufreq: Failed to set armdiv rate %dkHz: %d\n", | |
123 | freq, ret); | |
124 | return ret; | |
125 | } | |
126 | } | |
127 | ||
128 | return 0; | |
129 | } | |
130 | ||
131 | static int s3c2416_cpufreq_enter_dvs(struct s3c2416_data *s3c_freq, int idx) | |
132 | { | |
133 | #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE | |
134 | struct s3c2416_dvfs *dvfs; | |
135 | #endif | |
136 | int ret; | |
137 | ||
138 | if (s3c_freq->is_dvs) { | |
139 | pr_debug("cpufreq: already in dvs mode, nothing to do\n"); | |
140 | return 0; | |
141 | } | |
142 | ||
143 | pr_debug("cpufreq: switching armclk to hclk (%lukHz)\n", | |
144 | clk_get_rate(s3c_freq->hclk) / 1000); | |
145 | ret = clk_set_parent(s3c_freq->armclk, s3c_freq->hclk); | |
146 | if (ret < 0) { | |
147 | pr_err("cpufreq: Failed to switch armclk to hclk: %d\n", ret); | |
148 | return ret; | |
149 | } | |
150 | ||
151 | #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE | |
152 | /* changing the core voltage is only allowed when in dvs mode */ | |
153 | if (s3c_freq->vddarm) { | |
154 | dvfs = &s3c2416_dvfs_table[idx]; | |
155 | ||
156 | pr_debug("cpufreq: setting regultor to %d-%d\n", | |
157 | dvfs->vddarm_min, dvfs->vddarm_max); | |
158 | ret = regulator_set_voltage(s3c_freq->vddarm, | |
159 | dvfs->vddarm_min, | |
160 | dvfs->vddarm_max); | |
161 | ||
162 | /* when lowering the voltage failed, there is nothing to do */ | |
163 | if (ret != 0) | |
164 | pr_err("cpufreq: Failed to set VDDARM: %d\n", ret); | |
165 | } | |
166 | #endif | |
167 | ||
168 | s3c_freq->is_dvs = 1; | |
169 | ||
170 | return 0; | |
171 | } | |
172 | ||
173 | static int s3c2416_cpufreq_leave_dvs(struct s3c2416_data *s3c_freq, int idx) | |
174 | { | |
175 | #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE | |
176 | struct s3c2416_dvfs *dvfs; | |
177 | #endif | |
178 | int ret; | |
179 | ||
180 | if (!s3c_freq->is_dvs) { | |
181 | pr_debug("cpufreq: not in dvs mode, so can't leave\n"); | |
182 | return 0; | |
183 | } | |
184 | ||
185 | #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE | |
186 | if (s3c_freq->vddarm) { | |
187 | dvfs = &s3c2416_dvfs_table[idx]; | |
188 | ||
189 | pr_debug("cpufreq: setting regultor to %d-%d\n", | |
190 | dvfs->vddarm_min, dvfs->vddarm_max); | |
191 | ret = regulator_set_voltage(s3c_freq->vddarm, | |
192 | dvfs->vddarm_min, | |
193 | dvfs->vddarm_max); | |
194 | if (ret != 0) { | |
195 | pr_err("cpufreq: Failed to set VDDARM: %d\n", ret); | |
196 | return ret; | |
197 | } | |
198 | } | |
199 | #endif | |
200 | ||
201 | /* force armdiv to hclk frequency for transition from dvs*/ | |
202 | if (clk_get_rate(s3c_freq->armdiv) > clk_get_rate(s3c_freq->hclk)) { | |
203 | pr_debug("cpufreq: force armdiv to hclk frequency (%lukHz)\n", | |
204 | clk_get_rate(s3c_freq->hclk) / 1000); | |
205 | ret = s3c2416_cpufreq_set_armdiv(s3c_freq, | |
206 | clk_get_rate(s3c_freq->hclk) / 1000); | |
207 | if (ret < 0) { | |
208 | pr_err("cpufreq: Failed to to set the armdiv to %lukHz: %d\n", | |
209 | clk_get_rate(s3c_freq->hclk) / 1000, ret); | |
210 | return ret; | |
211 | } | |
212 | } | |
213 | ||
214 | pr_debug("cpufreq: switching armclk parent to armdiv (%lukHz)\n", | |
215 | clk_get_rate(s3c_freq->armdiv) / 1000); | |
216 | ||
217 | ret = clk_set_parent(s3c_freq->armclk, s3c_freq->armdiv); | |
218 | if (ret < 0) { | |
219 | pr_err("cpufreq: Failed to switch armclk clock parent to armdiv: %d\n", | |
220 | ret); | |
221 | return ret; | |
222 | } | |
223 | ||
224 | s3c_freq->is_dvs = 0; | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
229 | static int s3c2416_cpufreq_set_target(struct cpufreq_policy *policy, | |
230 | unsigned int target_freq, | |
231 | unsigned int relation) | |
232 | { | |
233 | struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; | |
234 | struct cpufreq_freqs freqs; | |
235 | int idx, ret, to_dvs = 0; | |
236 | unsigned int i; | |
237 | ||
238 | mutex_lock(&cpufreq_lock); | |
239 | ||
240 | pr_debug("cpufreq: to %dKHz, relation %d\n", target_freq, relation); | |
241 | ||
242 | ret = cpufreq_frequency_table_target(policy, s3c_freq->freq_table, | |
243 | target_freq, relation, &i); | |
244 | if (ret != 0) | |
245 | goto out; | |
246 | ||
247 | idx = s3c_freq->freq_table[i].index; | |
248 | ||
249 | if (idx == SOURCE_HCLK) | |
250 | to_dvs = 1; | |
251 | ||
252 | /* switching to dvs when it's not allowed */ | |
253 | if (to_dvs && s3c_freq->disable_dvs) { | |
254 | pr_debug("cpufreq: entering dvs mode not allowed\n"); | |
255 | ret = -EINVAL; | |
256 | goto out; | |
257 | } | |
258 | ||
259 | freqs.cpu = 0; | |
260 | freqs.flags = 0; | |
261 | freqs.old = s3c_freq->is_dvs ? FREQ_DVS | |
262 | : clk_get_rate(s3c_freq->armclk) / 1000; | |
263 | ||
264 | /* When leavin dvs mode, always switch the armdiv to the hclk rate | |
265 | * The S3C2416 has stability issues when switching directly to | |
266 | * higher frequencies. | |
267 | */ | |
268 | freqs.new = (s3c_freq->is_dvs && !to_dvs) | |
269 | ? clk_get_rate(s3c_freq->hclk) / 1000 | |
270 | : s3c_freq->freq_table[i].frequency; | |
271 | ||
272 | pr_debug("cpufreq: Transition %d-%dkHz\n", freqs.old, freqs.new); | |
273 | ||
274 | if (!to_dvs && freqs.old == freqs.new) | |
275 | goto out; | |
276 | ||
277 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
278 | ||
279 | if (to_dvs) { | |
280 | pr_debug("cpufreq: enter dvs\n"); | |
281 | ret = s3c2416_cpufreq_enter_dvs(s3c_freq, idx); | |
282 | } else if (s3c_freq->is_dvs) { | |
283 | pr_debug("cpufreq: leave dvs\n"); | |
284 | ret = s3c2416_cpufreq_leave_dvs(s3c_freq, idx); | |
285 | } else { | |
286 | pr_debug("cpufreq: change armdiv to %dkHz\n", freqs.new); | |
287 | ret = s3c2416_cpufreq_set_armdiv(s3c_freq, freqs.new); | |
288 | } | |
289 | ||
290 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); | |
291 | ||
292 | out: | |
293 | mutex_unlock(&cpufreq_lock); | |
294 | ||
295 | return ret; | |
296 | } | |
297 | ||
298 | #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE | |
299 | static void __init s3c2416_cpufreq_cfg_regulator(struct s3c2416_data *s3c_freq) | |
300 | { | |
301 | int count, v, i, found; | |
302 | struct cpufreq_frequency_table *freq; | |
303 | struct s3c2416_dvfs *dvfs; | |
304 | ||
305 | count = regulator_count_voltages(s3c_freq->vddarm); | |
306 | if (count < 0) { | |
307 | pr_err("cpufreq: Unable to check supported voltages\n"); | |
308 | return; | |
309 | } | |
310 | ||
311 | freq = s3c_freq->freq_table; | |
312 | while (count > 0 && freq->frequency != CPUFREQ_TABLE_END) { | |
313 | if (freq->frequency == CPUFREQ_ENTRY_INVALID) | |
314 | continue; | |
315 | ||
316 | dvfs = &s3c2416_dvfs_table[freq->index]; | |
317 | found = 0; | |
318 | ||
319 | /* Check only the min-voltage, more is always ok on S3C2416 */ | |
320 | for (i = 0; i < count; i++) { | |
321 | v = regulator_list_voltage(s3c_freq->vddarm, i); | |
322 | if (v >= dvfs->vddarm_min) | |
323 | found = 1; | |
324 | } | |
325 | ||
326 | if (!found) { | |
327 | pr_debug("cpufreq: %dkHz unsupported by regulator\n", | |
328 | freq->frequency); | |
329 | freq->frequency = CPUFREQ_ENTRY_INVALID; | |
330 | } | |
331 | ||
332 | freq++; | |
333 | } | |
334 | ||
335 | /* Guessed */ | |
336 | s3c_freq->regulator_latency = 1 * 1000 * 1000; | |
337 | } | |
338 | #endif | |
339 | ||
340 | static int s3c2416_cpufreq_reboot_notifier_evt(struct notifier_block *this, | |
341 | unsigned long event, void *ptr) | |
342 | { | |
343 | struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; | |
344 | int ret; | |
345 | ||
346 | mutex_lock(&cpufreq_lock); | |
347 | ||
348 | /* disable further changes */ | |
349 | s3c_freq->disable_dvs = 1; | |
350 | ||
351 | mutex_unlock(&cpufreq_lock); | |
352 | ||
353 | /* some boards don't reconfigure the regulator on reboot, which | |
354 | * could lead to undervolting the cpu when the clock is reset. | |
355 | * Therefore we always leave the DVS mode on reboot. | |
356 | */ | |
357 | if (s3c_freq->is_dvs) { | |
358 | pr_debug("cpufreq: leave dvs on reboot\n"); | |
359 | ret = cpufreq_driver_target(cpufreq_cpu_get(0), FREQ_SLEEP, 0); | |
360 | if (ret < 0) | |
361 | return NOTIFY_BAD; | |
362 | } | |
363 | ||
364 | return NOTIFY_DONE; | |
365 | } | |
366 | ||
367 | static struct notifier_block s3c2416_cpufreq_reboot_notifier = { | |
368 | .notifier_call = s3c2416_cpufreq_reboot_notifier_evt, | |
369 | }; | |
370 | ||
371 | static int __init s3c2416_cpufreq_driver_init(struct cpufreq_policy *policy) | |
372 | { | |
373 | struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; | |
374 | struct cpufreq_frequency_table *freq; | |
375 | struct clk *msysclk; | |
376 | unsigned long rate; | |
377 | int ret; | |
378 | ||
379 | if (policy->cpu != 0) | |
380 | return -EINVAL; | |
381 | ||
382 | msysclk = clk_get(NULL, "msysclk"); | |
383 | if (IS_ERR(msysclk)) { | |
384 | ret = PTR_ERR(msysclk); | |
385 | pr_err("cpufreq: Unable to obtain msysclk: %d\n", ret); | |
386 | return ret; | |
387 | } | |
388 | ||
389 | /* | |
390 | * S3C2416 and S3C2450 share the same processor-ID and also provide no | |
391 | * other means to distinguish them other than through the rate of | |
392 | * msysclk. On S3C2416 msysclk runs at 800MHz and on S3C2450 at 533MHz. | |
393 | */ | |
394 | rate = clk_get_rate(msysclk); | |
395 | if (rate == 800 * 1000 * 1000) { | |
396 | pr_info("cpufreq: msysclk running at %lukHz, using S3C2416 frequency table\n", | |
397 | rate / 1000); | |
398 | s3c_freq->freq_table = s3c2416_freq_table; | |
399 | policy->cpuinfo.max_freq = 400000; | |
400 | } else if (rate / 1000 == 534000) { | |
401 | pr_info("cpufreq: msysclk running at %lukHz, using S3C2450 frequency table\n", | |
402 | rate / 1000); | |
403 | s3c_freq->freq_table = s3c2450_freq_table; | |
404 | policy->cpuinfo.max_freq = 534000; | |
405 | } | |
406 | ||
407 | /* not needed anymore */ | |
408 | clk_put(msysclk); | |
409 | ||
410 | if (s3c_freq->freq_table == NULL) { | |
411 | pr_err("cpufreq: No frequency information for this CPU, msysclk at %lukHz\n", | |
412 | rate / 1000); | |
413 | return -ENODEV; | |
414 | } | |
415 | ||
416 | s3c_freq->is_dvs = 0; | |
417 | ||
418 | s3c_freq->armdiv = clk_get(NULL, "armdiv"); | |
419 | if (IS_ERR(s3c_freq->armdiv)) { | |
420 | ret = PTR_ERR(s3c_freq->armdiv); | |
421 | pr_err("cpufreq: Unable to obtain ARMDIV: %d\n", ret); | |
422 | return ret; | |
423 | } | |
424 | ||
425 | s3c_freq->hclk = clk_get(NULL, "hclk"); | |
426 | if (IS_ERR(s3c_freq->hclk)) { | |
427 | ret = PTR_ERR(s3c_freq->hclk); | |
428 | pr_err("cpufreq: Unable to obtain HCLK: %d\n", ret); | |
429 | goto err_hclk; | |
430 | } | |
431 | ||
432 | /* chech hclk rate, we only support the common 133MHz for now | |
433 | * hclk could also run at 66MHz, but this not often used | |
434 | */ | |
435 | rate = clk_get_rate(s3c_freq->hclk); | |
436 | if (rate < 133 * 1000 * 1000) { | |
437 | pr_err("cpufreq: HCLK not at 133MHz\n"); | |
438 | clk_put(s3c_freq->hclk); | |
439 | ret = -EINVAL; | |
440 | goto err_armclk; | |
441 | } | |
442 | ||
443 | s3c_freq->armclk = clk_get(NULL, "armclk"); | |
444 | if (IS_ERR(s3c_freq->armclk)) { | |
445 | ret = PTR_ERR(s3c_freq->armclk); | |
446 | pr_err("cpufreq: Unable to obtain ARMCLK: %d\n", ret); | |
447 | goto err_armclk; | |
448 | } | |
449 | ||
450 | #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE | |
451 | s3c_freq->vddarm = regulator_get(NULL, "vddarm"); | |
452 | if (IS_ERR(s3c_freq->vddarm)) { | |
453 | ret = PTR_ERR(s3c_freq->vddarm); | |
454 | pr_err("cpufreq: Failed to obtain VDDARM: %d\n", ret); | |
455 | goto err_vddarm; | |
456 | } | |
457 | ||
458 | s3c2416_cpufreq_cfg_regulator(s3c_freq); | |
459 | #else | |
460 | s3c_freq->regulator_latency = 0; | |
461 | #endif | |
462 | ||
463 | freq = s3c_freq->freq_table; | |
464 | while (freq->frequency != CPUFREQ_TABLE_END) { | |
465 | /* special handling for dvs mode */ | |
466 | if (freq->index == 0) { | |
467 | if (!s3c_freq->hclk) { | |
468 | pr_debug("cpufreq: %dkHz unsupported as it would need unavailable dvs mode\n", | |
469 | freq->frequency); | |
470 | freq->frequency = CPUFREQ_ENTRY_INVALID; | |
471 | } else { | |
472 | freq++; | |
473 | continue; | |
474 | } | |
475 | } | |
476 | ||
477 | /* Check for frequencies we can generate */ | |
478 | rate = clk_round_rate(s3c_freq->armdiv, | |
479 | freq->frequency * 1000); | |
480 | rate /= 1000; | |
481 | if (rate != freq->frequency) { | |
482 | pr_debug("cpufreq: %dkHz unsupported by clock (clk_round_rate return %lu)\n", | |
483 | freq->frequency, rate); | |
484 | freq->frequency = CPUFREQ_ENTRY_INVALID; | |
485 | } | |
486 | ||
487 | freq++; | |
488 | } | |
489 | ||
490 | policy->cur = clk_get_rate(s3c_freq->armclk) / 1000; | |
491 | ||
492 | /* Datasheet says PLL stabalisation time must be at least 300us, | |
493 | * so but add some fudge. (reference in LOCKCON0 register description) | |
494 | */ | |
495 | policy->cpuinfo.transition_latency = (500 * 1000) + | |
496 | s3c_freq->regulator_latency; | |
497 | ||
498 | ret = cpufreq_frequency_table_cpuinfo(policy, s3c_freq->freq_table); | |
499 | if (ret) | |
500 | goto err_freq_table; | |
501 | ||
502 | cpufreq_frequency_table_get_attr(s3c_freq->freq_table, 0); | |
503 | ||
504 | register_reboot_notifier(&s3c2416_cpufreq_reboot_notifier); | |
505 | ||
506 | return 0; | |
507 | ||
508 | err_freq_table: | |
509 | #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE | |
510 | regulator_put(s3c_freq->vddarm); | |
511 | err_vddarm: | |
512 | #endif | |
513 | clk_put(s3c_freq->armclk); | |
514 | err_armclk: | |
515 | clk_put(s3c_freq->hclk); | |
516 | err_hclk: | |
517 | clk_put(s3c_freq->armdiv); | |
518 | ||
519 | return ret; | |
520 | } | |
521 | ||
522 | static struct freq_attr *s3c2416_cpufreq_attr[] = { | |
523 | &cpufreq_freq_attr_scaling_available_freqs, | |
524 | NULL, | |
525 | }; | |
526 | ||
527 | static struct cpufreq_driver s3c2416_cpufreq_driver = { | |
528 | .owner = THIS_MODULE, | |
529 | .flags = 0, | |
530 | .verify = s3c2416_cpufreq_verify_speed, | |
531 | .target = s3c2416_cpufreq_set_target, | |
532 | .get = s3c2416_cpufreq_get_speed, | |
533 | .init = s3c2416_cpufreq_driver_init, | |
534 | .name = "s3c2416", | |
535 | .attr = s3c2416_cpufreq_attr, | |
536 | }; | |
537 | ||
538 | static int __init s3c2416_cpufreq_init(void) | |
539 | { | |
540 | return cpufreq_register_driver(&s3c2416_cpufreq_driver); | |
541 | } | |
542 | module_init(s3c2416_cpufreq_init); |