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 bool have_static_opps; 36 }; 37 38 static struct freq_attr *cpufreq_dt_attr[] = { 39 &cpufreq_freq_attr_scaling_available_freqs, 40 NULL, /* Extra space for boost-attr if required */ 41 NULL, 42 }; 43 44 static int set_target(struct cpufreq_policy *policy, unsigned int index) 45 { 46 struct private_data *priv = policy->driver_data; 47 unsigned long freq = policy->freq_table[index].frequency; 48 int ret; 49 50 ret = dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000); 51 52 if (!ret) { 53 arch_set_freq_scale(policy->related_cpus, freq, 54 policy->cpuinfo.max_freq); 55 } 56 57 return ret; 58 } 59 60 /* 61 * An earlier version of opp-v1 bindings used to name the regulator 62 * "cpu0-supply", we still need to handle that for backwards compatibility. 63 */ 64 static const char *find_supply_name(struct device *dev) 65 { 66 struct device_node *np; 67 struct property *pp; 68 int cpu = dev->id; 69 const char *name = NULL; 70 71 np = of_node_get(dev->of_node); 72 73 /* This must be valid for sure */ 74 if (WARN_ON(!np)) 75 return NULL; 76 77 /* Try "cpu0" for older DTs */ 78 if (!cpu) { 79 pp = of_find_property(np, "cpu0-supply", NULL); 80 if (pp) { 81 name = "cpu0"; 82 goto node_put; 83 } 84 } 85 86 pp = of_find_property(np, "cpu-supply", NULL); 87 if (pp) { 88 name = "cpu"; 89 goto node_put; 90 } 91 92 dev_dbg(dev, "no regulator for cpu%d\n", cpu); 93 node_put: 94 of_node_put(np); 95 return name; 96 } 97 98 static int resources_available(void) 99 { 100 struct device *cpu_dev; 101 struct regulator *cpu_reg; 102 struct clk *cpu_clk; 103 int ret = 0; 104 const char *name; 105 106 cpu_dev = get_cpu_device(0); 107 if (!cpu_dev) { 108 pr_err("failed to get cpu0 device\n"); 109 return -ENODEV; 110 } 111 112 cpu_clk = clk_get(cpu_dev, NULL); 113 ret = PTR_ERR_OR_ZERO(cpu_clk); 114 if (ret) { 115 /* 116 * If cpu's clk node is present, but clock is not yet 117 * registered, we should try defering probe. 118 */ 119 if (ret == -EPROBE_DEFER) 120 dev_dbg(cpu_dev, "clock not ready, retry\n"); 121 else 122 dev_err(cpu_dev, "failed to get clock: %d\n", ret); 123 124 return ret; 125 } 126 127 clk_put(cpu_clk); 128 129 name = find_supply_name(cpu_dev); 130 /* Platform doesn't require regulator */ 131 if (!name) 132 return 0; 133 134 cpu_reg = regulator_get_optional(cpu_dev, name); 135 ret = PTR_ERR_OR_ZERO(cpu_reg); 136 if (ret) { 137 /* 138 * If cpu's regulator supply node is present, but regulator is 139 * not yet registered, we should try defering probe. 140 */ 141 if (ret == -EPROBE_DEFER) 142 dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n"); 143 else 144 dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret); 145 146 return ret; 147 } 148 149 regulator_put(cpu_reg); 150 return 0; 151 } 152 153 static int cpufreq_init(struct cpufreq_policy *policy) 154 { 155 struct cpufreq_frequency_table *freq_table; 156 struct opp_table *opp_table = NULL; 157 struct private_data *priv; 158 struct device *cpu_dev; 159 struct clk *cpu_clk; 160 unsigned int transition_latency; 161 bool fallback = false; 162 const char *name; 163 int ret; 164 165 cpu_dev = get_cpu_device(policy->cpu); 166 if (!cpu_dev) { 167 pr_err("failed to get cpu%d device\n", policy->cpu); 168 return -ENODEV; 169 } 170 171 cpu_clk = clk_get(cpu_dev, NULL); 172 if (IS_ERR(cpu_clk)) { 173 ret = PTR_ERR(cpu_clk); 174 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret); 175 return ret; 176 } 177 178 /* Get OPP-sharing information from "operating-points-v2" bindings */ 179 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus); 180 if (ret) { 181 if (ret != -ENOENT) 182 goto out_put_clk; 183 184 /* 185 * operating-points-v2 not supported, fallback to old method of 186 * finding shared-OPPs for backward compatibility if the 187 * platform hasn't set sharing CPUs. 188 */ 189 if (dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus)) 190 fallback = true; 191 } 192 193 /* 194 * OPP layer will be taking care of regulators now, but it needs to know 195 * the name of the regulator first. 196 */ 197 name = find_supply_name(cpu_dev); 198 if (name) { 199 opp_table = dev_pm_opp_set_regulators(cpu_dev, &name, 1); 200 if (IS_ERR(opp_table)) { 201 ret = PTR_ERR(opp_table); 202 dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n", 203 policy->cpu, ret); 204 goto out_put_clk; 205 } 206 } 207 208 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 209 if (!priv) { 210 ret = -ENOMEM; 211 goto out_put_regulator; 212 } 213 214 priv->reg_name = name; 215 priv->opp_table = opp_table; 216 217 /* 218 * Initialize OPP tables for all policy->cpus. They will be shared by 219 * all CPUs which have marked their CPUs shared with OPP bindings. 220 * 221 * For platforms not using operating-points-v2 bindings, we do this 222 * before updating policy->cpus. Otherwise, we will end up creating 223 * duplicate OPPs for policy->cpus. 224 * 225 * OPPs might be populated at runtime, don't check for error here 226 */ 227 if (!dev_pm_opp_of_cpumask_add_table(policy->cpus)) 228 priv->have_static_opps = true; 229 230 /* 231 * But we need OPP table to function so if it is not there let's 232 * give platform code chance to provide it for us. 233 */ 234 ret = dev_pm_opp_get_opp_count(cpu_dev); 235 if (ret <= 0) { 236 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); 237 ret = -EPROBE_DEFER; 238 goto out_free_opp; 239 } 240 241 if (fallback) { 242 cpumask_setall(policy->cpus); 243 244 /* 245 * OPP tables are initialized only for policy->cpu, do it for 246 * others as well. 247 */ 248 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); 249 if (ret) 250 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", 251 __func__, ret); 252 } 253 254 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); 255 if (ret) { 256 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); 257 goto out_free_opp; 258 } 259 260 priv->cpu_dev = cpu_dev; 261 policy->driver_data = priv; 262 policy->clk = cpu_clk; 263 policy->freq_table = freq_table; 264 265 policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000; 266 267 /* Support turbo/boost mode */ 268 if (policy_has_boost_freq(policy)) { 269 /* This gets disabled by core on driver unregister */ 270 ret = cpufreq_enable_boost_support(); 271 if (ret) 272 goto out_free_cpufreq_table; 273 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs; 274 } 275 276 transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev); 277 if (!transition_latency) 278 transition_latency = CPUFREQ_ETERNAL; 279 280 policy->cpuinfo.transition_latency = transition_latency; 281 policy->dvfs_possible_from_any_cpu = true; 282 283 return 0; 284 285 out_free_cpufreq_table: 286 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); 287 out_free_opp: 288 if (priv->have_static_opps) 289 dev_pm_opp_of_cpumask_remove_table(policy->cpus); 290 kfree(priv); 291 out_put_regulator: 292 if (name) 293 dev_pm_opp_put_regulators(opp_table); 294 out_put_clk: 295 clk_put(cpu_clk); 296 297 return ret; 298 } 299 300 static int cpufreq_exit(struct cpufreq_policy *policy) 301 { 302 struct private_data *priv = policy->driver_data; 303 304 cpufreq_cooling_unregister(priv->cdev); 305 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); 306 if (priv->have_static_opps) 307 dev_pm_opp_of_cpumask_remove_table(policy->related_cpus); 308 if (priv->reg_name) 309 dev_pm_opp_put_regulators(priv->opp_table); 310 311 clk_put(policy->clk); 312 kfree(priv); 313 314 return 0; 315 } 316 317 static void cpufreq_ready(struct cpufreq_policy *policy) 318 { 319 struct private_data *priv = policy->driver_data; 320 321 priv->cdev = of_cpufreq_cooling_register(policy); 322 } 323 324 static struct cpufreq_driver dt_cpufreq_driver = { 325 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, 326 .verify = cpufreq_generic_frequency_table_verify, 327 .target_index = set_target, 328 .get = cpufreq_generic_get, 329 .init = cpufreq_init, 330 .exit = cpufreq_exit, 331 .ready = cpufreq_ready, 332 .name = "cpufreq-dt", 333 .attr = cpufreq_dt_attr, 334 .suspend = cpufreq_generic_suspend, 335 }; 336 337 static int dt_cpufreq_probe(struct platform_device *pdev) 338 { 339 struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev); 340 int ret; 341 342 /* 343 * All per-cluster (CPUs sharing clock/voltages) initialization is done 344 * from ->init(). In probe(), we just need to make sure that clk and 345 * regulators are available. Else defer probe and retry. 346 * 347 * FIXME: Is checking this only for CPU0 sufficient ? 348 */ 349 ret = resources_available(); 350 if (ret) 351 return ret; 352 353 if (data) { 354 if (data->have_governor_per_policy) 355 dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY; 356 357 dt_cpufreq_driver.resume = data->resume; 358 if (data->suspend) 359 dt_cpufreq_driver.suspend = data->suspend; 360 } 361 362 ret = cpufreq_register_driver(&dt_cpufreq_driver); 363 if (ret) 364 dev_err(&pdev->dev, "failed register driver: %d\n", ret); 365 366 return ret; 367 } 368 369 static int dt_cpufreq_remove(struct platform_device *pdev) 370 { 371 cpufreq_unregister_driver(&dt_cpufreq_driver); 372 return 0; 373 } 374 375 static struct platform_driver dt_cpufreq_platdrv = { 376 .driver = { 377 .name = "cpufreq-dt", 378 }, 379 .probe = dt_cpufreq_probe, 380 .remove = dt_cpufreq_remove, 381 }; 382 module_platform_driver(dt_cpufreq_platdrv); 383 384 MODULE_ALIAS("platform:cpufreq-dt"); 385 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); 386 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); 387 MODULE_DESCRIPTION("Generic cpufreq driver"); 388 MODULE_LICENSE("GPL"); 389