summaryrefslogtreecommitdiff
path: root/drivers/cpufreq/cpufreq-dt.c
blob: 88812437e8afd70aace3621de756cd65ba6ade5c (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
/*
 * Copyright (C) 2012 Freescale Semiconductor, Inc.
 *
 * Copyright (C) 2014 Linaro.
 * Viresh Kumar <viresh.kumar@linaro.org>
 *
 * The OPP code in function set_target() is reused from
 * drivers/cpufreq/omap-cpufreq.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

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

struct private_data {
	struct device *cpu_dev;
	struct regulator *cpu_reg;
	struct thermal_cooling_device *cdev;
	unsigned int voltage_tolerance; /* in percentage */
};

static int set_target(struct cpufreq_policy *policy, unsigned int index)
{
	struct dev_pm_opp *opp;
	struct cpufreq_frequency_table *freq_table = policy->freq_table;
	struct clk *cpu_clk = policy->clk;
	struct private_data *priv = policy->driver_data;
	struct device *cpu_dev = priv->cpu_dev;
	struct regulator *cpu_reg = priv->cpu_reg;
	unsigned long volt = 0, volt_old = 0, tol = 0;
	unsigned int old_freq, new_freq;
	long freq_Hz, freq_exact;
	int ret;

	freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
	if (freq_Hz <= 0)
		freq_Hz = freq_table[index].frequency * 1000;

	freq_exact = freq_Hz;
	new_freq = freq_Hz / 1000;
	old_freq = clk_get_rate(cpu_clk) / 1000;

	if (!IS_ERR(cpu_reg)) {
		unsigned long opp_freq;

		rcu_read_lock();
		opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
		if (IS_ERR(opp)) {
			rcu_read_unlock();
			dev_err(cpu_dev, "failed to find OPP for %ld\n",
				freq_Hz);
			return PTR_ERR(opp);
		}
		volt = dev_pm_opp_get_voltage(opp);
		opp_freq = dev_pm_opp_get_freq(opp);
		rcu_read_unlock();
		tol = volt * priv->voltage_tolerance / 100;
		volt_old = regulator_get_voltage(cpu_reg);
		dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n",
			opp_freq / 1000, volt);
	}

	dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
		old_freq / 1000, (volt_old > 0) ? volt_old / 1000 : -1,
		new_freq / 1000, volt ? volt / 1000 : -1);

	/* scaling up?  scale voltage before frequency */
	if (!IS_ERR(cpu_reg) && new_freq > old_freq) {
		ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
		if (ret) {
			dev_err(cpu_dev, "failed to scale voltage up: %d\n",
				ret);
			return ret;
		}
	}

	ret = clk_set_rate(cpu_clk, freq_exact);
	if (ret) {
		dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
		if (!IS_ERR(cpu_reg) && volt_old > 0)
			regulator_set_voltage_tol(cpu_reg, volt_old, tol);
		return ret;
	}

	/* scaling down?  scale voltage after frequency */
	if (!IS_ERR(cpu_reg) && new_freq < old_freq) {
		ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
		if (ret) {
			dev_err(cpu_dev, "failed to scale voltage down: %d\n",
				ret);
			clk_set_rate(cpu_clk, old_freq * 1000);
		}
	}

	return ret;
}

static int allocate_resources(int cpu, struct device **cdev,
			      struct regulator **creg, struct clk **cclk)
{
	struct device *cpu_dev;
	struct regulator *cpu_reg;
	struct clk *cpu_clk;
	int ret = 0;
	char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;

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

	/* Try "cpu0" for older DTs */
	if (!cpu)
		reg = reg_cpu0;
	else
		reg = reg_cpu;

try_again:
	cpu_reg = regulator_get_optional(cpu_dev, reg);
	if (IS_ERR(cpu_reg)) {
		/*
		 * If cpu's regulator supply node is present, but regulator is
		 * not yet registered, we should try defering probe.
		 */
		if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {
			dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
				cpu);
			return -EPROBE_DEFER;
		}

		/* Try with "cpu-supply" */
		if (reg == reg_cpu0) {
			reg = reg_cpu;
			goto try_again;
		}

		dev_dbg(cpu_dev, "no regulator for cpu%d: %ld\n",
			cpu, PTR_ERR(cpu_reg));
	}

	cpu_clk = clk_get(cpu_dev, NULL);
	if (IS_ERR(cpu_clk)) {
		/* put regulator */
		if (!IS_ERR(cpu_reg))
			regulator_put(cpu_reg);

		ret = PTR_ERR(cpu_clk);

		/*
		 * If cpu's clk node is present, but clock is not yet
		 * registered, we should try defering probe.
		 */
		if (ret == -EPROBE_DEFER)
			dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
		else
			dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
				ret);
	} else {
		*cdev = cpu_dev;
		*creg = cpu_reg;
		*cclk = cpu_clk;
	}

	return ret;
}

static int cpufreq_init(struct cpufreq_policy *policy)
{
	struct cpufreq_dt_platform_data *pd;
	struct cpufreq_frequency_table *freq_table;
	struct device_node *np;
	struct private_data *priv;
	struct device *cpu_dev;
	struct regulator *cpu_reg;
	struct clk *cpu_clk;
	unsigned long min_uV = ~0, max_uV = 0;
	unsigned int transition_latency;
	unsigned int sampling_rate = 0;
	int ret;

	ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
	if (ret) {
		pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
		return ret;
	}

	np = of_node_get(cpu_dev->of_node);
	if (!np) {
		dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
		ret = -ENOENT;
		goto out_put_reg_clk;
	}

	/* OPPs might be populated at runtime, don't check for error here */
	of_init_opp_table(cpu_dev);

	/*
	 * But we need OPP table to function so if it is not there let's
	 * give platform code chance to provide it for us.
	 */
	ret = dev_pm_opp_get_opp_count(cpu_dev);
	if (ret <= 0) {
		pr_debug("OPP table is not ready, deferring probe\n");
		ret = -EPROBE_DEFER;
		goto out_free_opp;
	}

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv) {
		ret = -ENOMEM;
		goto out_free_opp;
	}

	of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);

	if (of_property_read_u32(np, "sampling-rate", &sampling_rate))
		sampling_rate = 0;

	if (of_property_read_u32(np, "clock-latency", &transition_latency))
		transition_latency = CPUFREQ_ETERNAL;

	if (!IS_ERR(cpu_reg)) {
		unsigned long opp_freq = 0;

		/*
		 * Disable any OPPs where the connected regulator isn't able to
		 * provide the specified voltage and record minimum and maximum
		 * voltage levels.
		 */
		while (1) {
			struct dev_pm_opp *opp;
			unsigned long opp_uV, tol_uV;

			rcu_read_lock();
			opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq);
			if (IS_ERR(opp)) {
				rcu_read_unlock();
				break;
			}
			opp_uV = dev_pm_opp_get_voltage(opp);
			rcu_read_unlock();

			tol_uV = opp_uV * priv->voltage_tolerance / 100;
			if (regulator_is_supported_voltage(cpu_reg, opp_uV,
							   opp_uV + tol_uV)) {
				if (opp_uV < min_uV)
					min_uV = opp_uV;
				if (opp_uV > max_uV)
					max_uV = opp_uV;
			} else {
				dev_pm_opp_disable(cpu_dev, opp_freq);
			}

			opp_freq++;
		}

		ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
		if (ret > 0)
			transition_latency += ret * 1000;
	}

	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
	if (ret) {
		pr_err("failed to init cpufreq table: %d\n", ret);
		goto out_free_priv;
	}

	priv->cpu_dev = cpu_dev;
	priv->cpu_reg = cpu_reg;
	policy->driver_data = priv;

	policy->clk = cpu_clk;
	ret = cpufreq_table_validate_and_show(policy, freq_table);
	if (ret) {
		dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
			ret);
		goto out_free_cpufreq_table;
	}

	policy->cpuinfo.transition_latency = transition_latency;
	policy->cpuinfo.sampling_rate = sampling_rate;

	pd = cpufreq_get_driver_data();
	if (!pd || !pd->independent_clocks)
		cpumask_setall(policy->cpus);

	of_node_put(np);

	return 0;

out_free_cpufreq_table:
	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
out_free_priv:
	kfree(priv);
out_free_opp:
	of_free_opp_table(cpu_dev);
	of_node_put(np);
out_put_reg_clk:
	clk_put(cpu_clk);
	if (!IS_ERR(cpu_reg))
		regulator_put(cpu_reg);

	return ret;
}

static int cpufreq_exit(struct cpufreq_policy *policy)
{
	struct private_data *priv = policy->driver_data;

	cpufreq_cooling_unregister(priv->cdev);
	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
	of_free_opp_table(priv->cpu_dev);
	clk_put(policy->clk);
	if (!IS_ERR(priv->cpu_reg))
		regulator_put(priv->cpu_reg);
	kfree(priv);

	return 0;
}

static void cpufreq_ready(struct cpufreq_policy *policy)
{
	struct private_data *priv = policy->driver_data;
	struct device_node *np = of_node_get(priv->cpu_dev->of_node);

	if (WARN_ON(!np))
		return;

	/*
	 * For now, just loading the cooling device;
	 * thermal DT code takes care of matching them.
	 */
	if (of_find_property(np, "#cooling-cells", NULL)) {
		priv->cdev = of_cpufreq_cooling_register(np,
							 policy->related_cpus);
		if (IS_ERR(priv->cdev)) {
			dev_err(priv->cpu_dev,
				"running cpufreq without cooling device: %ld\n",
				PTR_ERR(priv->cdev));

			priv->cdev = NULL;
		}
	}

	of_node_put(np);
}

static struct cpufreq_driver dt_cpufreq_driver = {
	.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
	.verify = cpufreq_generic_frequency_table_verify,
	.target_index = set_target,
	.get = cpufreq_generic_get,
	.init = cpufreq_init,
	.exit = cpufreq_exit,
	.ready = cpufreq_ready,
	.name = "cpufreq-dt",
	.attr = cpufreq_generic_attr,
};

static int dt_cpufreq_probe(struct platform_device *pdev)
{
	struct device *cpu_dev;
	struct regulator *cpu_reg;
	struct clk *cpu_clk;
	int ret;

	/*
	 * All per-cluster (CPUs sharing clock/voltages) initialization is done
	 * from ->init(). In probe(), we just need to make sure that clk and
	 * regulators are available. Else defer probe and retry.
	 *
	 * FIXME: Is checking this only for CPU0 sufficient ?
	 */
	ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk);
	if (ret)
		return ret;

	clk_put(cpu_clk);
	if (!IS_ERR(cpu_reg))
		regulator_put(cpu_reg);

	dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);

	ret = cpufreq_register_driver(&dt_cpufreq_driver);
	if (ret)
		dev_err(cpu_dev, "failed register driver: %d\n", ret);

	return ret;
}

static int dt_cpufreq_remove(struct platform_device *pdev)
{
	cpufreq_unregister_driver(&dt_cpufreq_driver);
	return 0;
}

static struct platform_driver dt_cpufreq_platdrv = {
	.driver = {
		.name	= "cpufreq-dt",
	},
	.probe		= dt_cpufreq_probe,
	.remove		= dt_cpufreq_remove,
};
module_platform_driver(dt_cpufreq_platdrv);

MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
MODULE_DESCRIPTION("Generic cpufreq driver");
MODULE_LICENSE("GPL");