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1 | /* | |
2 | * Copyright (C) 2012 Freescale Semiconductor, Inc. | |
3 | * | |
4 | * Copyright (C) 2014 Linaro. | |
5 | * Viresh Kumar <viresh.kumar@linaro.org> | |
6 | * | |
7 | * The OPP code in function set_target() is reused from | |
8 | * drivers/cpufreq/omap-cpufreq.c | |
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 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
16 | ||
17 | #include <linux/clk.h> | |
18 | #include <linux/cpu.h> | |
19 | #include <linux/cpu_cooling.h> | |
20 | #include <linux/cpufreq.h> | |
21 | #include <linux/cpufreq-dt.h> | |
22 | #include <linux/cpumask.h> | |
23 | #include <linux/err.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/of.h> | |
26 | #include <linux/pm_opp.h> | |
27 | #include <linux/platform_device.h> | |
28 | #include <linux/regulator/consumer.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/thermal.h> | |
31 | ||
32 | struct private_data { | |
33 | struct device *cpu_dev; | |
34 | struct regulator *cpu_reg; | |
35 | struct thermal_cooling_device *cdev; | |
36 | unsigned int voltage_tolerance; /* in percentage */ | |
37 | }; | |
38 | ||
39 | static int set_target(struct cpufreq_policy *policy, unsigned int index) | |
40 | { | |
41 | struct dev_pm_opp *opp; | |
42 | struct cpufreq_frequency_table *freq_table = policy->freq_table; | |
43 | struct clk *cpu_clk = policy->clk; | |
44 | struct private_data *priv = policy->driver_data; | |
45 | struct device *cpu_dev = priv->cpu_dev; | |
46 | struct regulator *cpu_reg = priv->cpu_reg; | |
47 | unsigned long volt = 0, volt_old = 0, tol = 0; | |
48 | unsigned int old_freq, new_freq; | |
49 | long freq_Hz, freq_exact; | |
50 | int ret; | |
51 | ||
52 | freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000); | |
53 | if (freq_Hz <= 0) | |
54 | freq_Hz = freq_table[index].frequency * 1000; | |
55 | ||
56 | freq_exact = freq_Hz; | |
57 | new_freq = freq_Hz / 1000; | |
58 | old_freq = clk_get_rate(cpu_clk) / 1000; | |
59 | ||
60 | if (!IS_ERR(cpu_reg)) { | |
61 | unsigned long opp_freq; | |
62 | ||
63 | rcu_read_lock(); | |
64 | opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz); | |
65 | if (IS_ERR(opp)) { | |
66 | rcu_read_unlock(); | |
67 | dev_err(cpu_dev, "failed to find OPP for %ld\n", | |
68 | freq_Hz); | |
69 | return PTR_ERR(opp); | |
70 | } | |
71 | volt = dev_pm_opp_get_voltage(opp); | |
72 | opp_freq = dev_pm_opp_get_freq(opp); | |
73 | rcu_read_unlock(); | |
74 | tol = volt * priv->voltage_tolerance / 100; | |
75 | volt_old = regulator_get_voltage(cpu_reg); | |
76 | dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n", | |
77 | opp_freq / 1000, volt); | |
78 | } | |
79 | ||
80 | dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n", | |
81 | old_freq / 1000, (volt_old > 0) ? volt_old / 1000 : -1, | |
82 | new_freq / 1000, volt ? volt / 1000 : -1); | |
83 | ||
84 | /* scaling up? scale voltage before frequency */ | |
85 | if (!IS_ERR(cpu_reg) && new_freq > old_freq) { | |
86 | ret = regulator_set_voltage_tol(cpu_reg, volt, tol); | |
87 | if (ret) { | |
88 | dev_err(cpu_dev, "failed to scale voltage up: %d\n", | |
89 | ret); | |
90 | return ret; | |
91 | } | |
92 | } | |
93 | ||
94 | ret = clk_set_rate(cpu_clk, freq_exact); | |
95 | if (ret) { | |
96 | dev_err(cpu_dev, "failed to set clock rate: %d\n", ret); | |
97 | if (!IS_ERR(cpu_reg) && volt_old > 0) | |
98 | regulator_set_voltage_tol(cpu_reg, volt_old, tol); | |
99 | return ret; | |
100 | } | |
101 | ||
102 | /* scaling down? scale voltage after frequency */ | |
103 | if (!IS_ERR(cpu_reg) && new_freq < old_freq) { | |
104 | ret = regulator_set_voltage_tol(cpu_reg, volt, tol); | |
105 | if (ret) { | |
106 | dev_err(cpu_dev, "failed to scale voltage down: %d\n", | |
107 | ret); | |
108 | clk_set_rate(cpu_clk, old_freq * 1000); | |
109 | } | |
110 | } | |
111 | ||
112 | return ret; | |
113 | } | |
114 | ||
115 | static int allocate_resources(int cpu, struct device **cdev, | |
116 | struct regulator **creg, struct clk **cclk) | |
117 | { | |
118 | struct device *cpu_dev; | |
119 | struct regulator *cpu_reg; | |
120 | struct clk *cpu_clk; | |
121 | int ret = 0; | |
122 | char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg; | |
123 | ||
124 | cpu_dev = get_cpu_device(cpu); | |
125 | if (!cpu_dev) { | |
126 | pr_err("failed to get cpu%d device\n", cpu); | |
127 | return -ENODEV; | |
128 | } | |
129 | ||
130 | /* Try "cpu0" for older DTs */ | |
131 | if (!cpu) | |
132 | reg = reg_cpu0; | |
133 | else | |
134 | reg = reg_cpu; | |
135 | ||
136 | try_again: | |
137 | cpu_reg = regulator_get_optional(cpu_dev, reg); | |
138 | if (IS_ERR(cpu_reg)) { | |
139 | /* | |
140 | * If cpu's regulator supply node is present, but regulator is | |
141 | * not yet registered, we should try defering probe. | |
142 | */ | |
143 | if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) { | |
144 | dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n", | |
145 | cpu); | |
146 | return -EPROBE_DEFER; | |
147 | } | |
148 | ||
149 | /* Try with "cpu-supply" */ | |
150 | if (reg == reg_cpu0) { | |
151 | reg = reg_cpu; | |
152 | goto try_again; | |
153 | } | |
154 | ||
155 | dev_dbg(cpu_dev, "no regulator for cpu%d: %ld\n", | |
156 | cpu, PTR_ERR(cpu_reg)); | |
157 | } | |
158 | ||
159 | cpu_clk = clk_get(cpu_dev, NULL); | |
160 | if (IS_ERR(cpu_clk)) { | |
161 | /* put regulator */ | |
162 | if (!IS_ERR(cpu_reg)) | |
163 | regulator_put(cpu_reg); | |
164 | ||
165 | ret = PTR_ERR(cpu_clk); | |
166 | ||
167 | /* | |
168 | * If cpu's clk node is present, but clock is not yet | |
169 | * registered, we should try defering probe. | |
170 | */ | |
171 | if (ret == -EPROBE_DEFER) | |
172 | dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu); | |
173 | else | |
174 | dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu, | |
175 | ret); | |
176 | } else { | |
177 | *cdev = cpu_dev; | |
178 | *creg = cpu_reg; | |
179 | *cclk = cpu_clk; | |
180 | } | |
181 | ||
182 | return ret; | |
183 | } | |
184 | ||
185 | static int cpufreq_init(struct cpufreq_policy *policy) | |
186 | { | |
187 | struct cpufreq_dt_platform_data *pd; | |
188 | struct cpufreq_frequency_table *freq_table; | |
189 | struct device_node *np; | |
190 | struct private_data *priv; | |
191 | struct device *cpu_dev; | |
192 | struct regulator *cpu_reg; | |
193 | struct clk *cpu_clk; | |
194 | unsigned long min_uV = ~0, max_uV = 0; | |
195 | unsigned int transition_latency; | |
196 | int ret; | |
197 | ||
198 | ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk); | |
199 | if (ret) { | |
200 | pr_err("%s: Failed to allocate resources: %d\n", __func__, ret); | |
201 | return ret; | |
202 | } | |
203 | ||
204 | np = of_node_get(cpu_dev->of_node); | |
205 | if (!np) { | |
206 | dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu); | |
207 | ret = -ENOENT; | |
208 | goto out_put_reg_clk; | |
209 | } | |
210 | ||
211 | /* OPPs might be populated at runtime, don't check for error here */ | |
212 | of_init_opp_table(cpu_dev); | |
213 | ||
214 | /* | |
215 | * But we need OPP table to function so if it is not there let's | |
216 | * give platform code chance to provide it for us. | |
217 | */ | |
218 | ret = dev_pm_opp_get_opp_count(cpu_dev); | |
219 | if (ret <= 0) { | |
220 | pr_debug("OPP table is not ready, deferring probe\n"); | |
221 | ret = -EPROBE_DEFER; | |
222 | goto out_free_opp; | |
223 | } | |
224 | ||
225 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
226 | if (!priv) { | |
227 | ret = -ENOMEM; | |
228 | goto out_free_opp; | |
229 | } | |
230 | ||
231 | of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance); | |
232 | ||
233 | if (of_property_read_u32(np, "clock-latency", &transition_latency)) | |
234 | transition_latency = CPUFREQ_ETERNAL; | |
235 | ||
236 | if (!IS_ERR(cpu_reg)) { | |
237 | unsigned long opp_freq = 0; | |
238 | ||
239 | /* | |
240 | * Disable any OPPs where the connected regulator isn't able to | |
241 | * provide the specified voltage and record minimum and maximum | |
242 | * voltage levels. | |
243 | */ | |
244 | while (1) { | |
245 | struct dev_pm_opp *opp; | |
246 | unsigned long opp_uV, tol_uV; | |
247 | ||
248 | rcu_read_lock(); | |
249 | opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq); | |
250 | if (IS_ERR(opp)) { | |
251 | rcu_read_unlock(); | |
252 | break; | |
253 | } | |
254 | opp_uV = dev_pm_opp_get_voltage(opp); | |
255 | rcu_read_unlock(); | |
256 | ||
257 | tol_uV = opp_uV * priv->voltage_tolerance / 100; | |
258 | if (regulator_is_supported_voltage(cpu_reg, opp_uV, | |
259 | opp_uV + tol_uV)) { | |
260 | if (opp_uV < min_uV) | |
261 | min_uV = opp_uV; | |
262 | if (opp_uV > max_uV) | |
263 | max_uV = opp_uV; | |
264 | } else { | |
265 | dev_pm_opp_disable(cpu_dev, opp_freq); | |
266 | } | |
267 | ||
268 | opp_freq++; | |
269 | } | |
270 | ||
271 | ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV); | |
272 | if (ret > 0) | |
273 | transition_latency += ret * 1000; | |
274 | } | |
275 | ||
276 | ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); | |
277 | if (ret) { | |
278 | pr_err("failed to init cpufreq table: %d\n", ret); | |
279 | goto out_free_priv; | |
280 | } | |
281 | ||
282 | priv->cpu_dev = cpu_dev; | |
283 | priv->cpu_reg = cpu_reg; | |
284 | policy->driver_data = priv; | |
285 | ||
286 | policy->clk = cpu_clk; | |
287 | ret = cpufreq_table_validate_and_show(policy, freq_table); | |
288 | if (ret) { | |
289 | dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__, | |
290 | ret); | |
291 | goto out_free_cpufreq_table; | |
292 | } | |
293 | ||
294 | policy->cpuinfo.transition_latency = transition_latency; | |
295 | ||
296 | pd = cpufreq_get_driver_data(); | |
297 | if (!pd || !pd->independent_clocks) | |
298 | cpumask_setall(policy->cpus); | |
299 | ||
300 | of_node_put(np); | |
301 | ||
302 | return 0; | |
303 | ||
304 | out_free_cpufreq_table: | |
305 | dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); | |
306 | out_free_priv: | |
307 | kfree(priv); | |
308 | out_free_opp: | |
309 | of_free_opp_table(cpu_dev); | |
310 | of_node_put(np); | |
311 | out_put_reg_clk: | |
312 | clk_put(cpu_clk); | |
313 | if (!IS_ERR(cpu_reg)) | |
314 | regulator_put(cpu_reg); | |
315 | ||
316 | return ret; | |
317 | } | |
318 | ||
319 | static int cpufreq_exit(struct cpufreq_policy *policy) | |
320 | { | |
321 | struct private_data *priv = policy->driver_data; | |
322 | ||
323 | cpufreq_cooling_unregister(priv->cdev); | |
324 | dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); | |
325 | of_free_opp_table(priv->cpu_dev); | |
326 | clk_put(policy->clk); | |
327 | if (!IS_ERR(priv->cpu_reg)) | |
328 | regulator_put(priv->cpu_reg); | |
329 | kfree(priv); | |
330 | ||
331 | return 0; | |
332 | } | |
333 | ||
334 | static void cpufreq_ready(struct cpufreq_policy *policy) | |
335 | { | |
336 | struct private_data *priv = policy->driver_data; | |
337 | struct device_node *np = of_node_get(priv->cpu_dev->of_node); | |
338 | ||
339 | if (WARN_ON(!np)) | |
340 | return; | |
341 | ||
342 | /* | |
343 | * For now, just loading the cooling device; | |
344 | * thermal DT code takes care of matching them. | |
345 | */ | |
346 | if (of_find_property(np, "#cooling-cells", NULL)) { | |
347 | priv->cdev = of_cpufreq_cooling_register(np, | |
348 | policy->related_cpus); | |
349 | if (IS_ERR(priv->cdev)) { | |
350 | dev_err(priv->cpu_dev, | |
351 | "running cpufreq without cooling device: %ld\n", | |
352 | PTR_ERR(priv->cdev)); | |
353 | ||
354 | priv->cdev = NULL; | |
355 | } | |
356 | } | |
357 | ||
358 | of_node_put(np); | |
359 | } | |
360 | ||
361 | static struct cpufreq_driver dt_cpufreq_driver = { | |
362 | .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, | |
363 | .verify = cpufreq_generic_frequency_table_verify, | |
364 | .target_index = set_target, | |
365 | .get = cpufreq_generic_get, | |
366 | .init = cpufreq_init, | |
367 | .exit = cpufreq_exit, | |
368 | .ready = cpufreq_ready, | |
369 | .name = "cpufreq-dt", | |
370 | .attr = cpufreq_generic_attr, | |
371 | }; | |
372 | ||
373 | static int dt_cpufreq_probe(struct platform_device *pdev) | |
374 | { | |
375 | struct device *cpu_dev; | |
376 | struct regulator *cpu_reg; | |
377 | struct clk *cpu_clk; | |
378 | int ret; | |
379 | ||
380 | /* | |
381 | * All per-cluster (CPUs sharing clock/voltages) initialization is done | |
382 | * from ->init(). In probe(), we just need to make sure that clk and | |
383 | * regulators are available. Else defer probe and retry. | |
384 | * | |
385 | * FIXME: Is checking this only for CPU0 sufficient ? | |
386 | */ | |
387 | ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk); | |
388 | if (ret) | |
389 | return ret; | |
390 | ||
391 | clk_put(cpu_clk); | |
392 | if (!IS_ERR(cpu_reg)) | |
393 | regulator_put(cpu_reg); | |
394 | ||
395 | dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev); | |
396 | ||
397 | ret = cpufreq_register_driver(&dt_cpufreq_driver); | |
398 | if (ret) | |
399 | dev_err(cpu_dev, "failed register driver: %d\n", ret); | |
400 | ||
401 | return ret; | |
402 | } | |
403 | ||
404 | static int dt_cpufreq_remove(struct platform_device *pdev) | |
405 | { | |
406 | cpufreq_unregister_driver(&dt_cpufreq_driver); | |
407 | return 0; | |
408 | } | |
409 | ||
410 | static struct platform_driver dt_cpufreq_platdrv = { | |
411 | .driver = { | |
412 | .name = "cpufreq-dt", | |
413 | }, | |
414 | .probe = dt_cpufreq_probe, | |
415 | .remove = dt_cpufreq_remove, | |
416 | }; | |
417 | module_platform_driver(dt_cpufreq_platdrv); | |
418 | ||
419 | MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); | |
420 | MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); | |
421 | MODULE_DESCRIPTION("Generic cpufreq driver"); | |
422 | MODULE_LICENSE("GPL"); |