Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6
[linux-2.6-microblaze.git] / drivers / cpufreq / cpufreq-dt.c
1 /*
2  * Copyright (C) 2012 Freescale Semiconductor, Inc.
3  *
4  * Copyright (C) 2014 Linaro.
5  * Viresh Kumar <viresh.kumar@linaro.org>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11
12 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
13
14 #include <linux/clk.h>
15 #include <linux/cpu.h>
16 #include <linux/cpu_cooling.h>
17 #include <linux/cpufreq.h>
18 #include <linux/cpumask.h>
19 #include <linux/err.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/pm_opp.h>
23 #include <linux/platform_device.h>
24 #include <linux/regulator/consumer.h>
25 #include <linux/slab.h>
26 #include <linux/thermal.h>
27
28 #include "cpufreq-dt.h"
29
30 struct private_data {
31         struct opp_table *opp_table;
32         struct device *cpu_dev;
33         struct thermal_cooling_device *cdev;
34         const char *reg_name;
35 };
36
37 static struct freq_attr *cpufreq_dt_attr[] = {
38         &cpufreq_freq_attr_scaling_available_freqs,
39         NULL,   /* Extra space for boost-attr if required */
40         NULL,
41 };
42
43 static int set_target(struct cpufreq_policy *policy, unsigned int index)
44 {
45         struct private_data *priv = policy->driver_data;
46
47         return dev_pm_opp_set_rate(priv->cpu_dev,
48                                    policy->freq_table[index].frequency * 1000);
49 }
50
51 /*
52  * An earlier version of opp-v1 bindings used to name the regulator
53  * "cpu0-supply", we still need to handle that for backwards compatibility.
54  */
55 static const char *find_supply_name(struct device *dev)
56 {
57         struct device_node *np;
58         struct property *pp;
59         int cpu = dev->id;
60         const char *name = NULL;
61
62         np = of_node_get(dev->of_node);
63
64         /* This must be valid for sure */
65         if (WARN_ON(!np))
66                 return NULL;
67
68         /* Try "cpu0" for older DTs */
69         if (!cpu) {
70                 pp = of_find_property(np, "cpu0-supply", NULL);
71                 if (pp) {
72                         name = "cpu0";
73                         goto node_put;
74                 }
75         }
76
77         pp = of_find_property(np, "cpu-supply", NULL);
78         if (pp) {
79                 name = "cpu";
80                 goto node_put;
81         }
82
83         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
84 node_put:
85         of_node_put(np);
86         return name;
87 }
88
89 static int resources_available(void)
90 {
91         struct device *cpu_dev;
92         struct regulator *cpu_reg;
93         struct clk *cpu_clk;
94         int ret = 0;
95         const char *name;
96
97         cpu_dev = get_cpu_device(0);
98         if (!cpu_dev) {
99                 pr_err("failed to get cpu0 device\n");
100                 return -ENODEV;
101         }
102
103         cpu_clk = clk_get(cpu_dev, NULL);
104         ret = PTR_ERR_OR_ZERO(cpu_clk);
105         if (ret) {
106                 /*
107                  * If cpu's clk node is present, but clock is not yet
108                  * registered, we should try defering probe.
109                  */
110                 if (ret == -EPROBE_DEFER)
111                         dev_dbg(cpu_dev, "clock not ready, retry\n");
112                 else
113                         dev_err(cpu_dev, "failed to get clock: %d\n", ret);
114
115                 return ret;
116         }
117
118         clk_put(cpu_clk);
119
120         name = find_supply_name(cpu_dev);
121         /* Platform doesn't require regulator */
122         if (!name)
123                 return 0;
124
125         cpu_reg = regulator_get_optional(cpu_dev, name);
126         ret = PTR_ERR_OR_ZERO(cpu_reg);
127         if (ret) {
128                 /*
129                  * If cpu's regulator supply node is present, but regulator is
130                  * not yet registered, we should try defering probe.
131                  */
132                 if (ret == -EPROBE_DEFER)
133                         dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n");
134                 else
135                         dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret);
136
137                 return ret;
138         }
139
140         regulator_put(cpu_reg);
141         return 0;
142 }
143
144 static int cpufreq_init(struct cpufreq_policy *policy)
145 {
146         struct cpufreq_frequency_table *freq_table;
147         struct opp_table *opp_table = NULL;
148         struct private_data *priv;
149         struct device *cpu_dev;
150         struct clk *cpu_clk;
151         unsigned int transition_latency;
152         bool fallback = false;
153         const char *name;
154         int ret;
155
156         cpu_dev = get_cpu_device(policy->cpu);
157         if (!cpu_dev) {
158                 pr_err("failed to get cpu%d device\n", policy->cpu);
159                 return -ENODEV;
160         }
161
162         cpu_clk = clk_get(cpu_dev, NULL);
163         if (IS_ERR(cpu_clk)) {
164                 ret = PTR_ERR(cpu_clk);
165                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
166                 return ret;
167         }
168
169         /* Get OPP-sharing information from "operating-points-v2" bindings */
170         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
171         if (ret) {
172                 if (ret != -ENOENT)
173                         goto out_put_clk;
174
175                 /*
176                  * operating-points-v2 not supported, fallback to old method of
177                  * finding shared-OPPs for backward compatibility if the
178                  * platform hasn't set sharing CPUs.
179                  */
180                 if (dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus))
181                         fallback = true;
182         }
183
184         /*
185          * OPP layer will be taking care of regulators now, but it needs to know
186          * the name of the regulator first.
187          */
188         name = find_supply_name(cpu_dev);
189         if (name) {
190                 opp_table = dev_pm_opp_set_regulators(cpu_dev, &name, 1);
191                 if (IS_ERR(opp_table)) {
192                         ret = PTR_ERR(opp_table);
193                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
194                                 policy->cpu, ret);
195                         goto out_put_clk;
196                 }
197         }
198
199         /*
200          * Initialize OPP tables for all policy->cpus. They will be shared by
201          * all CPUs which have marked their CPUs shared with OPP bindings.
202          *
203          * For platforms not using operating-points-v2 bindings, we do this
204          * before updating policy->cpus. Otherwise, we will end up creating
205          * duplicate OPPs for policy->cpus.
206          *
207          * OPPs might be populated at runtime, don't check for error here
208          */
209         dev_pm_opp_of_cpumask_add_table(policy->cpus);
210
211         /*
212          * But we need OPP table to function so if it is not there let's
213          * give platform code chance to provide it for us.
214          */
215         ret = dev_pm_opp_get_opp_count(cpu_dev);
216         if (ret <= 0) {
217                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
218                 ret = -EPROBE_DEFER;
219                 goto out_free_opp;
220         }
221
222         if (fallback) {
223                 cpumask_setall(policy->cpus);
224
225                 /*
226                  * OPP tables are initialized only for policy->cpu, do it for
227                  * others as well.
228                  */
229                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
230                 if (ret)
231                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
232                                 __func__, ret);
233         }
234
235         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
236         if (!priv) {
237                 ret = -ENOMEM;
238                 goto out_free_opp;
239         }
240
241         priv->reg_name = name;
242         priv->opp_table = opp_table;
243
244         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
245         if (ret) {
246                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
247                 goto out_free_priv;
248         }
249
250         priv->cpu_dev = cpu_dev;
251         policy->driver_data = priv;
252         policy->clk = cpu_clk;
253
254         policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
255
256         ret = cpufreq_table_validate_and_show(policy, freq_table);
257         if (ret) {
258                 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
259                         ret);
260                 goto out_free_cpufreq_table;
261         }
262
263         /* Support turbo/boost mode */
264         if (policy_has_boost_freq(policy)) {
265                 /* This gets disabled by core on driver unregister */
266                 ret = cpufreq_enable_boost_support();
267                 if (ret)
268                         goto out_free_cpufreq_table;
269                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
270         }
271
272         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
273         if (!transition_latency)
274                 transition_latency = CPUFREQ_ETERNAL;
275
276         policy->cpuinfo.transition_latency = transition_latency;
277
278         return 0;
279
280 out_free_cpufreq_table:
281         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
282 out_free_priv:
283         kfree(priv);
284 out_free_opp:
285         dev_pm_opp_of_cpumask_remove_table(policy->cpus);
286         if (name)
287                 dev_pm_opp_put_regulators(opp_table);
288 out_put_clk:
289         clk_put(cpu_clk);
290
291         return ret;
292 }
293
294 static int cpufreq_exit(struct cpufreq_policy *policy)
295 {
296         struct private_data *priv = policy->driver_data;
297
298         cpufreq_cooling_unregister(priv->cdev);
299         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
300         dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
301         if (priv->reg_name)
302                 dev_pm_opp_put_regulators(priv->opp_table);
303
304         clk_put(policy->clk);
305         kfree(priv);
306
307         return 0;
308 }
309
310 static void cpufreq_ready(struct cpufreq_policy *policy)
311 {
312         struct private_data *priv = policy->driver_data;
313         struct device_node *np = of_node_get(priv->cpu_dev->of_node);
314
315         if (WARN_ON(!np))
316                 return;
317
318         /*
319          * For now, just loading the cooling device;
320          * thermal DT code takes care of matching them.
321          */
322         if (of_find_property(np, "#cooling-cells", NULL)) {
323                 u32 power_coefficient = 0;
324
325                 of_property_read_u32(np, "dynamic-power-coefficient",
326                                      &power_coefficient);
327
328                 priv->cdev = of_cpufreq_power_cooling_register(np,
329                                 policy->related_cpus, power_coefficient, NULL);
330                 if (IS_ERR(priv->cdev)) {
331                         dev_err(priv->cpu_dev,
332                                 "running cpufreq without cooling device: %ld\n",
333                                 PTR_ERR(priv->cdev));
334
335                         priv->cdev = NULL;
336                 }
337         }
338
339         of_node_put(np);
340 }
341
342 static struct cpufreq_driver dt_cpufreq_driver = {
343         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
344         .verify = cpufreq_generic_frequency_table_verify,
345         .target_index = set_target,
346         .get = cpufreq_generic_get,
347         .init = cpufreq_init,
348         .exit = cpufreq_exit,
349         .ready = cpufreq_ready,
350         .name = "cpufreq-dt",
351         .attr = cpufreq_dt_attr,
352         .suspend = cpufreq_generic_suspend,
353 };
354
355 static int dt_cpufreq_probe(struct platform_device *pdev)
356 {
357         struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
358         int ret;
359
360         /*
361          * All per-cluster (CPUs sharing clock/voltages) initialization is done
362          * from ->init(). In probe(), we just need to make sure that clk and
363          * regulators are available. Else defer probe and retry.
364          *
365          * FIXME: Is checking this only for CPU0 sufficient ?
366          */
367         ret = resources_available();
368         if (ret)
369                 return ret;
370
371         if (data && data->have_governor_per_policy)
372                 dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
373
374         ret = cpufreq_register_driver(&dt_cpufreq_driver);
375         if (ret)
376                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
377
378         return ret;
379 }
380
381 static int dt_cpufreq_remove(struct platform_device *pdev)
382 {
383         cpufreq_unregister_driver(&dt_cpufreq_driver);
384         return 0;
385 }
386
387 static struct platform_driver dt_cpufreq_platdrv = {
388         .driver = {
389                 .name   = "cpufreq-dt",
390         },
391         .probe          = dt_cpufreq_probe,
392         .remove         = dt_cpufreq_remove,
393 };
394 module_platform_driver(dt_cpufreq_platdrv);
395
396 MODULE_ALIAS("platform:cpufreq-dt");
397 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
398 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
399 MODULE_DESCRIPTION("Generic cpufreq driver");
400 MODULE_LICENSE("GPL");