summaryrefslogtreecommitdiff
path: root/drivers/cpufreq/mediatek-cpufreq.c
blob: 7d1212c9b7c88af34ead03f1efd83a28f2ae85bb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015 Linaro Ltd.
 * Author: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
 */

#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/thermal.h>

#define MIN_VOLT_SHIFT		(100000)
#define MAX_VOLT_SHIFT		(200000)
#define MAX_VOLT_LIMIT		(1150000)
#define VOLT_TOL		(10000)

/*
 * The struct mtk_cpu_dvfs_info holds necessary information for doing CPU DVFS
 * on each CPU power/clock domain of Mediatek SoCs. Each CPU cluster in
 * Mediatek SoCs has two voltage inputs, Vproc and Vsram. In some cases the two
 * voltage inputs need to be controlled under a hardware limitation:
 * 100mV < Vsram - Vproc < 200mV
 *
 * When scaling the clock frequency of a CPU clock domain, the clock source
 * needs to be switched to another stable PLL clock temporarily until
 * the original PLL becomes stable at target frequency.
 */
struct mtk_cpu_dvfs_info {
	struct cpumask cpus;
	struct device *cpu_dev;
	struct regulator *proc_reg;
	struct regulator *sram_reg;
	struct clk *cpu_clk;
	struct clk *inter_clk;
	struct list_head list_head;
	int intermediate_voltage;
	bool need_voltage_tracking;
};

static LIST_HEAD(dvfs_info_list);

static struct mtk_cpu_dvfs_info *mtk_cpu_dvfs_info_lookup(int cpu)
{
	struct mtk_cpu_dvfs_info *info;

	list_for_each_entry(info, &dvfs_info_list, list_head) {
		if (cpumask_test_cpu(cpu, &info->cpus))
			return info;
	}

	return NULL;
}

static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
					int new_vproc)
{
	struct regulator *proc_reg = info->proc_reg;
	struct regulator *sram_reg = info->sram_reg;
	int old_vproc, old_vsram, new_vsram, vsram, vproc, ret;

	old_vproc = regulator_get_voltage(proc_reg);
	if (old_vproc < 0) {
		pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
		return old_vproc;
	}
	/* Vsram should not exceed the maximum allowed voltage of SoC. */
	new_vsram = min(new_vproc + MIN_VOLT_SHIFT, MAX_VOLT_LIMIT);

	if (old_vproc < new_vproc) {
		/*
		 * When scaling up voltages, Vsram and Vproc scale up step
		 * by step. At each step, set Vsram to (Vproc + 200mV) first,
		 * then set Vproc to (Vsram - 100mV).
		 * Keep doing it until Vsram and Vproc hit target voltages.
		 */
		do {
			old_vsram = regulator_get_voltage(sram_reg);
			if (old_vsram < 0) {
				pr_err("%s: invalid Vsram value: %d\n",
				       __func__, old_vsram);
				return old_vsram;
			}
			old_vproc = regulator_get_voltage(proc_reg);
			if (old_vproc < 0) {
				pr_err("%s: invalid Vproc value: %d\n",
				       __func__, old_vproc);
				return old_vproc;
			}

			vsram = min(new_vsram, old_vproc + MAX_VOLT_SHIFT);

			if (vsram + VOLT_TOL >= MAX_VOLT_LIMIT) {
				vsram = MAX_VOLT_LIMIT;

				/*
				 * If the target Vsram hits the maximum voltage,
				 * try to set the exact voltage value first.
				 */
				ret = regulator_set_voltage(sram_reg, vsram,
							    vsram);
				if (ret)
					ret = regulator_set_voltage(sram_reg,
							vsram - VOLT_TOL,
							vsram);

				vproc = new_vproc;
			} else {
				ret = regulator_set_voltage(sram_reg, vsram,
							    vsram + VOLT_TOL);

				vproc = vsram - MIN_VOLT_SHIFT;
			}
			if (ret)
				return ret;

			ret = regulator_set_voltage(proc_reg, vproc,
						    vproc + VOLT_TOL);
			if (ret) {
				regulator_set_voltage(sram_reg, old_vsram,
						      old_vsram);
				return ret;
			}
		} while (vproc < new_vproc || vsram < new_vsram);
	} else if (old_vproc > new_vproc) {
		/*
		 * When scaling down voltages, Vsram and Vproc scale down step
		 * by step. At each step, set Vproc to (Vsram - 200mV) first,
		 * then set Vproc to (Vproc + 100mV).
		 * Keep doing it until Vsram and Vproc hit target voltages.
		 */
		do {
			old_vproc = regulator_get_voltage(proc_reg);
			if (old_vproc < 0) {
				pr_err("%s: invalid Vproc value: %d\n",
				       __func__, old_vproc);
				return old_vproc;
			}
			old_vsram = regulator_get_voltage(sram_reg);
			if (old_vsram < 0) {
				pr_err("%s: invalid Vsram value: %d\n",
				       __func__, old_vsram);
				return old_vsram;
			}

			vproc = max(new_vproc, old_vsram - MAX_VOLT_SHIFT);
			ret = regulator_set_voltage(proc_reg, vproc,
						    vproc + VOLT_TOL);
			if (ret)
				return ret;

			if (vproc == new_vproc)
				vsram = new_vsram;
			else
				vsram = max(new_vsram, vproc + MIN_VOLT_SHIFT);

			if (vsram + VOLT_TOL >= MAX_VOLT_LIMIT) {
				vsram = MAX_VOLT_LIMIT;

				/*
				 * If the target Vsram hits the maximum voltage,
				 * try to set the exact voltage value first.
				 */
				ret = regulator_set_voltage(sram_reg, vsram,
							    vsram);
				if (ret)
					ret = regulator_set_voltage(sram_reg,
							vsram - VOLT_TOL,
							vsram);
			} else {
				ret = regulator_set_voltage(sram_reg, vsram,
							    vsram + VOLT_TOL);
			}

			if (ret) {
				regulator_set_voltage(proc_reg, old_vproc,
						      old_vproc);
				return ret;
			}
		} while (vproc > new_vproc + VOLT_TOL ||
			 vsram > new_vsram + VOLT_TOL);
	}

	return 0;
}

static int mtk_cpufreq_set_voltage(struct mtk_cpu_dvfs_info *info, int vproc)
{
	if (info->need_voltage_tracking)
		return mtk_cpufreq_voltage_tracking(info, vproc);
	else
		return regulator_set_voltage(info->proc_reg, vproc,
					     vproc + VOLT_TOL);
}

static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
				  unsigned int index)
{
	struct cpufreq_frequency_table *freq_table = policy->freq_table;
	struct clk *cpu_clk = policy->clk;
	struct clk *armpll = clk_get_parent(cpu_clk);
	struct mtk_cpu_dvfs_info *info = policy->driver_data;
	struct device *cpu_dev = info->cpu_dev;
	struct dev_pm_opp *opp;
	long freq_hz, old_freq_hz;
	int vproc, old_vproc, inter_vproc, target_vproc, ret;

	inter_vproc = info->intermediate_voltage;

	old_freq_hz = clk_get_rate(cpu_clk);
	old_vproc = regulator_get_voltage(info->proc_reg);
	if (old_vproc < 0) {
		pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
		return old_vproc;
	}

	freq_hz = freq_table[index].frequency * 1000;

	opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
	if (IS_ERR(opp)) {
		pr_err("cpu%d: failed to find OPP for %ld\n",
		       policy->cpu, freq_hz);
		return PTR_ERR(opp);
	}
	vproc = dev_pm_opp_get_voltage(opp);
	dev_pm_opp_put(opp);

	/*
	 * If the new voltage or the intermediate voltage is higher than the
	 * current voltage, scale up voltage first.
	 */
	target_vproc = (inter_vproc > vproc) ? inter_vproc : vproc;
	if (old_vproc < target_vproc) {
		ret = mtk_cpufreq_set_voltage(info, target_vproc);
		if (ret) {
			pr_err("cpu%d: failed to scale up voltage!\n",
			       policy->cpu);
			mtk_cpufreq_set_voltage(info, old_vproc);
			return ret;
		}
	}

	/* Reparent the CPU clock to intermediate clock. */
	ret = clk_set_parent(cpu_clk, info->inter_clk);
	if (ret) {
		pr_err("cpu%d: failed to re-parent cpu clock!\n",
		       policy->cpu);
		mtk_cpufreq_set_voltage(info, old_vproc);
		WARN_ON(1);
		return ret;
	}

	/* Set the original PLL to target rate. */
	ret = clk_set_rate(armpll, freq_hz);
	if (ret) {
		pr_err("cpu%d: failed to scale cpu clock rate!\n",
		       policy->cpu);
		clk_set_parent(cpu_clk, armpll);
		mtk_cpufreq_set_voltage(info, old_vproc);
		return ret;
	}

	/* Set parent of CPU clock back to the original PLL. */
	ret = clk_set_parent(cpu_clk, armpll);
	if (ret) {
		pr_err("cpu%d: failed to re-parent cpu clock!\n",
		       policy->cpu);
		mtk_cpufreq_set_voltage(info, inter_vproc);
		WARN_ON(1);
		return ret;
	}

	/*
	 * If the new voltage is lower than the intermediate voltage or the
	 * original voltage, scale down to the new voltage.
	 */
	if (vproc < inter_vproc || vproc < old_vproc) {
		ret = mtk_cpufreq_set_voltage(info, vproc);
		if (ret) {
			pr_err("cpu%d: failed to scale down voltage!\n",
			       policy->cpu);
			clk_set_parent(cpu_clk, info->inter_clk);
			clk_set_rate(armpll, old_freq_hz);
			clk_set_parent(cpu_clk, armpll);
			return ret;
		}
	}

	return 0;
}

#define DYNAMIC_POWER "dynamic-power-coefficient"

static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
{
	struct device *cpu_dev;
	struct regulator *proc_reg = ERR_PTR(-ENODEV);
	struct regulator *sram_reg = ERR_PTR(-ENODEV);
	struct clk *cpu_clk = ERR_PTR(-ENODEV);
	struct clk *inter_clk = ERR_PTR(-ENODEV);
	struct dev_pm_opp *opp;
	unsigned long rate;
	int ret;

	cpu_dev = get_cpu_device(cpu);
	if (!cpu_dev) {
		pr_err("failed to get cpu%d device\n", cpu);
		return -ENODEV;
	}

	cpu_clk = clk_get(cpu_dev, "cpu");
	if (IS_ERR(cpu_clk)) {
		if (PTR_ERR(cpu_clk) == -EPROBE_DEFER)
			pr_warn("cpu clk for cpu%d not ready, retry.\n", cpu);
		else
			pr_err("failed to get cpu clk for cpu%d\n", cpu);

		ret = PTR_ERR(cpu_clk);
		return ret;
	}

	inter_clk = clk_get(cpu_dev, "intermediate");
	if (IS_ERR(inter_clk)) {
		if (PTR_ERR(inter_clk) == -EPROBE_DEFER)
			pr_warn("intermediate clk for cpu%d not ready, retry.\n",
				cpu);
		else
			pr_err("failed to get intermediate clk for cpu%d\n",
			       cpu);

		ret = PTR_ERR(inter_clk);
		goto out_free_resources;
	}

	proc_reg = regulator_get_optional(cpu_dev, "proc");
	if (IS_ERR(proc_reg)) {
		if (PTR_ERR(proc_reg) == -EPROBE_DEFER)
			pr_warn("proc regulator for cpu%d not ready, retry.\n",
				cpu);
		else
			pr_err("failed to get proc regulator for cpu%d\n",
			       cpu);

		ret = PTR_ERR(proc_reg);
		goto out_free_resources;
	}

	/* Both presence and absence of sram regulator are valid cases. */
	sram_reg = regulator_get_exclusive(cpu_dev, "sram");

	/* Get OPP-sharing information from "operating-points-v2" bindings */
	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, &info->cpus);
	if (ret) {
		pr_err("failed to get OPP-sharing information for cpu%d\n",
		       cpu);
		goto out_free_resources;
	}

	ret = dev_pm_opp_of_cpumask_add_table(&info->cpus);
	if (ret) {
		pr_warn("no OPP table for cpu%d\n", cpu);
		goto out_free_resources;
	}

	/* Search a safe voltage for intermediate frequency. */
	rate = clk_get_rate(inter_clk);
	opp = dev_pm_opp_find_freq_ceil(cpu_dev, &rate);
	if (IS_ERR(opp)) {
		pr_err("failed to get intermediate opp for cpu%d\n", cpu);
		ret = PTR_ERR(opp);
		goto out_free_opp_table;
	}
	info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
	dev_pm_opp_put(opp);

	info->cpu_dev = cpu_dev;
	info->proc_reg = proc_reg;
	info->sram_reg = IS_ERR(sram_reg) ? NULL : sram_reg;
	info->cpu_clk = cpu_clk;
	info->inter_clk = inter_clk;

	/*
	 * If SRAM regulator is present, software "voltage tracking" is needed
	 * for this CPU power domain.
	 */
	info->need_voltage_tracking = !IS_ERR(sram_reg);

	return 0;

out_free_opp_table:
	dev_pm_opp_of_cpumask_remove_table(&info->cpus);

out_free_resources:
	if (!IS_ERR(proc_reg))
		regulator_put(proc_reg);
	if (!IS_ERR(sram_reg))
		regulator_put(sram_reg);
	if (!IS_ERR(cpu_clk))
		clk_put(cpu_clk);
	if (!IS_ERR(inter_clk))
		clk_put(inter_clk);

	return ret;
}

static void mtk_cpu_dvfs_info_release(struct mtk_cpu_dvfs_info *info)
{
	if (!IS_ERR(info->proc_reg))
		regulator_put(info->proc_reg);
	if (!IS_ERR(info->sram_reg))
		regulator_put(info->sram_reg);
	if (!IS_ERR(info->cpu_clk))
		clk_put(info->cpu_clk);
	if (!IS_ERR(info->inter_clk))
		clk_put(info->inter_clk);

	dev_pm_opp_of_cpumask_remove_table(&info->cpus);
}

static int mtk_cpufreq_init(struct cpufreq_policy *policy)
{
	struct mtk_cpu_dvfs_info *info;
	struct cpufreq_frequency_table *freq_table;
	int ret;

	info = mtk_cpu_dvfs_info_lookup(policy->cpu);
	if (!info) {
		pr_err("dvfs info for cpu%d is not initialized.\n",
		       policy->cpu);
		return -EINVAL;
	}

	ret = dev_pm_opp_init_cpufreq_table(info->cpu_dev, &freq_table);
	if (ret) {
		pr_err("failed to init cpufreq table for cpu%d: %d\n",
		       policy->cpu, ret);
		return ret;
	}

	cpumask_copy(policy->cpus, &info->cpus);
	policy->freq_table = freq_table;
	policy->driver_data = info;
	policy->clk = info->cpu_clk;

	dev_pm_opp_of_register_em(info->cpu_dev, policy->cpus);

	return 0;
}

static int mtk_cpufreq_exit(struct cpufreq_policy *policy)
{
	struct mtk_cpu_dvfs_info *info = policy->driver_data;

	dev_pm_opp_free_cpufreq_table(info->cpu_dev, &policy->freq_table);

	return 0;
}

static struct cpufreq_driver mtk_cpufreq_driver = {
	.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
		 CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
		 CPUFREQ_IS_COOLING_DEV,
	.verify = cpufreq_generic_frequency_table_verify,
	.target_index = mtk_cpufreq_set_target,
	.get = cpufreq_generic_get,
	.init = mtk_cpufreq_init,
	.exit = mtk_cpufreq_exit,
	.name = "mtk-cpufreq",
	.attr = cpufreq_generic_attr,
};

static int mtk_cpufreq_probe(struct platform_device *pdev)
{
	struct mtk_cpu_dvfs_info *info, *tmp;
	int cpu, ret;

	for_each_possible_cpu(cpu) {
		info = mtk_cpu_dvfs_info_lookup(cpu);
		if (info)
			continue;

		info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
		if (!info) {
			ret = -ENOMEM;
			goto release_dvfs_info_list;
		}

		ret = mtk_cpu_dvfs_info_init(info, cpu);
		if (ret) {
			dev_err(&pdev->dev,
				"failed to initialize dvfs info for cpu%d\n",
				cpu);
			goto release_dvfs_info_list;
		}

		list_add(&info->list_head, &dvfs_info_list);
	}

	ret = cpufreq_register_driver(&mtk_cpufreq_driver);
	if (ret) {
		dev_err(&pdev->dev, "failed to register mtk cpufreq driver\n");
		goto release_dvfs_info_list;
	}

	return 0;

release_dvfs_info_list:
	list_for_each_entry_safe(info, tmp, &dvfs_info_list, list_head) {
		mtk_cpu_dvfs_info_release(info);
		list_del(&info->list_head);
	}

	return ret;
}

static struct platform_driver mtk_cpufreq_platdrv = {
	.driver = {
		.name	= "mtk-cpufreq",
	},
	.probe		= mtk_cpufreq_probe,
};

/* List of machines supported by this driver */
static const struct of_device_id mtk_cpufreq_machines[] __initconst = {
	{ .compatible = "mediatek,mt2701", },
	{ .compatible = "mediatek,mt2712", },
	{ .compatible = "mediatek,mt7622", },
	{ .compatible = "mediatek,mt7623", },
	{ .compatible = "mediatek,mt817x", },
	{ .compatible = "mediatek,mt8173", },
	{ .compatible = "mediatek,mt8176", },
	{ .compatible = "mediatek,mt8183", },
	{ .compatible = "mediatek,mt8516", },

	{ }
};

static int __init mtk_cpufreq_driver_init(void)
{
	struct device_node *np;
	const struct of_device_id *match;
	struct platform_device *pdev;
	int err;

	np = of_find_node_by_path("/");
	if (!np)
		return -ENODEV;

	match = of_match_node(mtk_cpufreq_machines, np);
	of_node_put(np);
	if (!match) {
		pr_debug("Machine is not compatible with mtk-cpufreq\n");
		return -ENODEV;
	}

	err = platform_driver_register(&mtk_cpufreq_platdrv);
	if (err)
		return err;

	/*
	 * Since there's no place to hold device registration code and no
	 * device tree based way to match cpufreq driver yet, both the driver
	 * and the device registration codes are put here to handle defer
	 * probing.
	 */
	pdev = platform_device_register_simple("mtk-cpufreq", -1, NULL, 0);
	if (IS_ERR(pdev)) {
		pr_err("failed to register mtk-cpufreq platform device\n");
		return PTR_ERR(pdev);
	}

	return 0;
}
device_initcall(mtk_cpufreq_driver_init);

MODULE_DESCRIPTION("MediaTek CPUFreq driver");
MODULE_AUTHOR("Pi-Cheng Chen <pi-cheng.chen@linaro.org>");
MODULE_LICENSE("GPL v2");