aboutsummaryrefslogtreecommitdiff
path: root/drivers/cpufreq/cpufreq-dt.c
blob: ece52863ba62e66cfd87e335299dbdf5388404c6 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Freescale Semiconductor, Inc.
 *
 * Copyright (C) 2014 Linaro.
 * Viresh Kumar <viresh.kumar@linaro.org>
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/list.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>

#include "cpufreq-dt.h"

struct private_data {
	struct list_head node;

	cpumask_var_t cpus;
	struct device *cpu_dev;
	struct opp_table *opp_table;
	struct cpufreq_frequency_table *freq_table;
	bool have_static_opps;
};

static LIST_HEAD(priv_list);

static struct freq_attr *cpufreq_dt_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,   /* Extra space for boost-attr if required */
	NULL,
};

static struct private_data *cpufreq_dt_find_data(int cpu)
{
	struct private_data *priv;

	list_for_each_entry(priv, &priv_list, node) {
		if (cpumask_test_cpu(cpu, priv->cpus))
			return priv;
	}

	return NULL;
}

static int set_target(struct cpufreq_policy *policy, unsigned int index)
{
	struct private_data *priv = policy->driver_data;
	unsigned long freq = policy->freq_table[index].frequency;

	return dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000);
}

/*
 * An earlier version of opp-v1 bindings used to name the regulator
 * "cpu0-supply", we still need to handle that for backwards compatibility.
 */
static const char *find_supply_name(struct device *dev)
{
	struct device_node *np;
	struct property *pp;
	int cpu = dev->id;
	const char *name = NULL;

	np = of_node_get(dev->of_node);

	/* This must be valid for sure */
	if (WARN_ON(!np))
		return NULL;

	/* Try "cpu0" for older DTs */
	if (!cpu) {
		pp = of_find_property(np, "cpu0-supply", NULL);
		if (pp) {
			name = "cpu0";
			goto node_put;
		}
	}

	pp = of_find_property(np, "cpu-supply", NULL);
	if (pp) {
		name = "cpu";
		goto node_put;
	}

	dev_dbg(dev, "no regulator for cpu%d\n", cpu);
node_put:
	of_node_put(np);
	return name;
}

static int cpufreq_init(struct cpufreq_policy *policy)
{
	struct private_data *priv;
	struct device *cpu_dev;
	struct clk *cpu_clk;
	unsigned int transition_latency;
	int ret;

	priv = cpufreq_dt_find_data(policy->cpu);
	if (!priv) {
		pr_err("failed to find data for cpu%d\n", policy->cpu);
		return -ENODEV;
	}
	cpu_dev = priv->cpu_dev;

	cpu_clk = clk_get(cpu_dev, NULL);
	if (IS_ERR(cpu_clk)) {
		ret = PTR_ERR(cpu_clk);
		dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
		return ret;
	}

	transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
	if (!transition_latency)
		transition_latency = CPUFREQ_ETERNAL;

	cpumask_copy(policy->cpus, priv->cpus);
	policy->driver_data = priv;
	policy->clk = cpu_clk;
	policy->freq_table = priv->freq_table;
	policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
	policy->cpuinfo.transition_latency = transition_latency;
	policy->dvfs_possible_from_any_cpu = true;

	/* Support turbo/boost mode */
	if (policy_has_boost_freq(policy)) {
		/* This gets disabled by core on driver unregister */
		ret = cpufreq_enable_boost_support();
		if (ret)
			goto out_clk_put;
		cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
	}

	dev_pm_opp_of_register_em(cpu_dev, policy->cpus);

	return 0;

out_clk_put:
	clk_put(cpu_clk);

	return ret;
}

static int cpufreq_online(struct cpufreq_policy *policy)
{
	/* We did light-weight tear down earlier, nothing to do here */
	return 0;
}

static int cpufreq_offline(struct cpufreq_policy *policy)
{
	/*
	 * Preserve policy->driver_data and don't free resources on light-weight
	 * tear down.
	 */
	return 0;
}

static int cpufreq_exit(struct cpufreq_policy *policy)
{
	clk_put(policy->clk);
	return 0;
}

static struct cpufreq_driver dt_cpufreq_driver = {
	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
		 CPUFREQ_IS_COOLING_DEV,
	.verify = cpufreq_generic_frequency_table_verify,
	.target_index = set_target,
	.get = cpufreq_generic_get,
	.init = cpufreq_init,
	.exit = cpufreq_exit,
	.online = cpufreq_online,
	.offline = cpufreq_offline,
	.name = "cpufreq-dt",
	.attr = cpufreq_dt_attr,
	.suspend = cpufreq_generic_suspend,
};

static int dt_cpufreq_early_init(struct device *dev, int cpu)
{
	struct private_data *priv;
	struct device *cpu_dev;
	bool fallback = false;
	const char *reg_name;
	int ret;

	/* Check if this CPU is already covered by some other policy */
	if (cpufreq_dt_find_data(cpu))
		return 0;

	cpu_dev = get_cpu_device(cpu);
	if (!cpu_dev)
		return -EPROBE_DEFER;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
		return -ENOMEM;

	cpumask_set_cpu(cpu, priv->cpus);
	priv->cpu_dev = cpu_dev;

	/*
	 * OPP layer will be taking care of regulators now, but it needs to know
	 * the name of the regulator first.
	 */
	reg_name = find_supply_name(cpu_dev);
	if (reg_name) {
		priv->opp_table = dev_pm_opp_set_regulators(cpu_dev, &reg_name,
							    1);
		if (IS_ERR(priv->opp_table)) {
			ret = PTR_ERR(priv->opp_table);
			if (ret != -EPROBE_DEFER)
				dev_err(cpu_dev, "failed to set regulators: %d\n",
					ret);
			goto free_cpumask;
		}
	}

	/* Get OPP-sharing information from "operating-points-v2" bindings */
	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
	if (ret) {
		if (ret != -ENOENT)
			goto out;

		/*
		 * operating-points-v2 not supported, fallback to all CPUs share
		 * OPP for backward compatibility if the platform hasn't set
		 * sharing CPUs.
		 */
		if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus))
			fallback = true;
	}

	/*
	 * Initialize OPP tables for all priv->cpus. They will be shared by
	 * all CPUs which have marked their CPUs shared with OPP bindings.
	 *
	 * For platforms not using operating-points-v2 bindings, we do this
	 * before updating priv->cpus. Otherwise, we will end up creating
	 * duplicate OPPs for the CPUs.
	 *
	 * OPPs might be populated at runtime, don't fail for error here unless
	 * it is -EPROBE_DEFER.
	 */
	ret = dev_pm_opp_of_cpumask_add_table(priv->cpus);
	if (!ret) {
		priv->have_static_opps = true;
	} else if (ret == -EPROBE_DEFER) {
		goto out;
	}

	/*
	 * The OPP table must be initialized, statically or dynamically, by this
	 * point.
	 */
	ret = dev_pm_opp_get_opp_count(cpu_dev);
	if (ret <= 0) {
		dev_err(cpu_dev, "OPP table can't be empty\n");
		ret = -ENODEV;
		goto out;
	}

	if (fallback) {
		cpumask_setall(priv->cpus);
		ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
		if (ret)
			dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
				__func__, ret);
	}

	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &priv->freq_table);
	if (ret) {
		dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
		goto out;
	}

	list_add(&priv->node, &priv_list);
	return 0;

out:
	if (priv->have_static_opps)
		dev_pm_opp_of_cpumask_remove_table(priv->cpus);
	dev_pm_opp_put_regulators(priv->opp_table);
free_cpumask:
	free_cpumask_var(priv->cpus);
	return ret;
}

static void dt_cpufreq_release(void)
{
	struct private_data *priv, *tmp;

	list_for_each_entry_safe(priv, tmp, &priv_list, node) {
		dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &priv->freq_table);
		if (priv->have_static_opps)
			dev_pm_opp_of_cpumask_remove_table(priv->cpus);
		dev_pm_opp_put_regulators(priv->opp_table);
		free_cpumask_var(priv->cpus);
		list_del(&priv->node);
	}
}

static int dt_cpufreq_probe(struct platform_device *pdev)
{
	struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
	int ret, cpu;

	/* Request resources early so we can return in case of -EPROBE_DEFER */
	for_each_possible_cpu(cpu) {
		ret = dt_cpufreq_early_init(&pdev->dev, cpu);
		if (ret)
			goto err;
	}

	if (data) {
		if (data->have_governor_per_policy)
			dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;

		dt_cpufreq_driver.resume = data->resume;
		if (data->suspend)
			dt_cpufreq_driver.suspend = data->suspend;
		if (data->get_intermediate) {
			dt_cpufreq_driver.target_intermediate = data->target_intermediate;
			dt_cpufreq_driver.get_intermediate = data->get_intermediate;
		}
	}

	ret = cpufreq_register_driver(&dt_cpufreq_driver);
	if (ret) {
		dev_err(&pdev->dev, "failed register driver: %d\n", ret);
		goto err;
	}

	return 0;
err:
	dt_cpufreq_release();
	return ret;
}

static int dt_cpufreq_remove(struct platform_device *pdev)
{
	cpufreq_unregister_driver(&dt_cpufreq_driver);
	dt_cpufreq_release();
	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_ALIAS("platform:cpufreq-dt");
MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
MODULE_DESCRIPTION("Generic cpufreq driver");
MODULE_LICENSE("GPL");