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