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/cpufreq.h> 17 #include <linux/cpumask.h> 18 #include <linux/err.h> 19 #include <linux/module.h> 20 #include <linux/of.h> 21 #include <linux/pm_opp.h> 22 #include <linux/platform_device.h> 23 #include <linux/regulator/consumer.h> 24 #include <linux/slab.h> 25 #include <linux/thermal.h> 26 27 #include "cpufreq-dt.h" 28 29 struct private_data { 30 struct opp_table *opp_table; 31 struct device *cpu_dev; 32 const char *reg_name; 33 bool have_static_opps; 34 }; 35 36 static struct freq_attr *cpufreq_dt_attr[] = { 37 &cpufreq_freq_attr_scaling_available_freqs, 38 NULL, /* Extra space for boost-attr if required */ 39 NULL, 40 }; 41 42 static int set_target(struct cpufreq_policy *policy, unsigned int index) 43 { 44 struct private_data *priv = policy->driver_data; 45 unsigned long freq = policy->freq_table[index].frequency; 46 int ret; 47 48 ret = dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000); 49 50 if (!ret) { 51 arch_set_freq_scale(policy->related_cpus, freq, 52 policy->cpuinfo.max_freq); 53 } 54 55 return ret; 56 } 57 58 /* 59 * An earlier version of opp-v1 bindings used to name the regulator 60 * "cpu0-supply", we still need to handle that for backwards compatibility. 61 */ 62 static const char *find_supply_name(struct device *dev) 63 { 64 struct device_node *np; 65 struct property *pp; 66 int cpu = dev->id; 67 const char *name = NULL; 68 69 np = of_node_get(dev->of_node); 70 71 /* This must be valid for sure */ 72 if (WARN_ON(!np)) 73 return NULL; 74 75 /* Try "cpu0" for older DTs */ 76 if (!cpu) { 77 pp = of_find_property(np, "cpu0-supply", NULL); 78 if (pp) { 79 name = "cpu0"; 80 goto node_put; 81 } 82 } 83 84 pp = of_find_property(np, "cpu-supply", NULL); 85 if (pp) { 86 name = "cpu"; 87 goto node_put; 88 } 89 90 dev_dbg(dev, "no regulator for cpu%d\n", cpu); 91 node_put: 92 of_node_put(np); 93 return name; 94 } 95 96 static int resources_available(void) 97 { 98 struct device *cpu_dev; 99 struct regulator *cpu_reg; 100 struct clk *cpu_clk; 101 int ret = 0; 102 const char *name; 103 104 cpu_dev = get_cpu_device(0); 105 if (!cpu_dev) { 106 pr_err("failed to get cpu0 device\n"); 107 return -ENODEV; 108 } 109 110 cpu_clk = clk_get(cpu_dev, NULL); 111 ret = PTR_ERR_OR_ZERO(cpu_clk); 112 if (ret) { 113 /* 114 * If cpu's clk node is present, but clock is not yet 115 * registered, we should try defering probe. 116 */ 117 if (ret == -EPROBE_DEFER) 118 dev_dbg(cpu_dev, "clock not ready, retry\n"); 119 else 120 dev_err(cpu_dev, "failed to get clock: %d\n", ret); 121 122 return ret; 123 } 124 125 clk_put(cpu_clk); 126 127 name = find_supply_name(cpu_dev); 128 /* Platform doesn't require regulator */ 129 if (!name) 130 return 0; 131 132 cpu_reg = regulator_get_optional(cpu_dev, name); 133 ret = PTR_ERR_OR_ZERO(cpu_reg); 134 if (ret) { 135 /* 136 * If cpu's regulator supply node is present, but regulator is 137 * not yet registered, we should try defering probe. 138 */ 139 if (ret == -EPROBE_DEFER) 140 dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n"); 141 else 142 dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret); 143 144 return ret; 145 } 146 147 regulator_put(cpu_reg); 148 return 0; 149 } 150 151 static int cpufreq_init(struct cpufreq_policy *policy) 152 { 153 struct cpufreq_frequency_table *freq_table; 154 struct opp_table *opp_table = NULL; 155 struct private_data *priv; 156 struct device *cpu_dev; 157 struct clk *cpu_clk; 158 unsigned int transition_latency; 159 bool fallback = false; 160 const char *name; 161 int ret; 162 163 cpu_dev = get_cpu_device(policy->cpu); 164 if (!cpu_dev) { 165 pr_err("failed to get cpu%d device\n", policy->cpu); 166 return -ENODEV; 167 } 168 169 cpu_clk = clk_get(cpu_dev, NULL); 170 if (IS_ERR(cpu_clk)) { 171 ret = PTR_ERR(cpu_clk); 172 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret); 173 return ret; 174 } 175 176 /* Get OPP-sharing information from "operating-points-v2" bindings */ 177 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus); 178 if (ret) { 179 if (ret != -ENOENT) 180 goto out_put_clk; 181 182 /* 183 * operating-points-v2 not supported, fallback to old method of 184 * finding shared-OPPs for backward compatibility if the 185 * platform hasn't set sharing CPUs. 186 */ 187 if (dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus)) 188 fallback = true; 189 } 190 191 /* 192 * OPP layer will be taking care of regulators now, but it needs to know 193 * the name of the regulator first. 194 */ 195 name = find_supply_name(cpu_dev); 196 if (name) { 197 opp_table = dev_pm_opp_set_regulators(cpu_dev, &name, 1); 198 if (IS_ERR(opp_table)) { 199 ret = PTR_ERR(opp_table); 200 dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n", 201 policy->cpu, ret); 202 goto out_put_clk; 203 } 204 } 205 206 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 207 if (!priv) { 208 ret = -ENOMEM; 209 goto out_put_regulator; 210 } 211 212 priv->reg_name = name; 213 priv->opp_table = opp_table; 214 215 /* 216 * Initialize OPP tables for all policy->cpus. They will be shared by 217 * all CPUs which have marked their CPUs shared with OPP bindings. 218 * 219 * For platforms not using operating-points-v2 bindings, we do this 220 * before updating policy->cpus. Otherwise, we will end up creating 221 * duplicate OPPs for policy->cpus. 222 * 223 * OPPs might be populated at runtime, don't check for error here 224 */ 225 if (!dev_pm_opp_of_cpumask_add_table(policy->cpus)) 226 priv->have_static_opps = true; 227 228 /* 229 * But we need OPP table to function so if it is not there let's 230 * give platform code chance to provide it for us. 231 */ 232 ret = dev_pm_opp_get_opp_count(cpu_dev); 233 if (ret <= 0) { 234 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); 235 ret = -EPROBE_DEFER; 236 goto out_free_opp; 237 } 238 239 if (fallback) { 240 cpumask_setall(policy->cpus); 241 242 /* 243 * OPP tables are initialized only for policy->cpu, do it for 244 * others as well. 245 */ 246 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); 247 if (ret) 248 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", 249 __func__, ret); 250 } 251 252 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); 253 if (ret) { 254 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); 255 goto out_free_opp; 256 } 257 258 priv->cpu_dev = cpu_dev; 259 policy->driver_data = priv; 260 policy->clk = cpu_clk; 261 policy->freq_table = freq_table; 262 263 policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000; 264 265 /* Support turbo/boost mode */ 266 if (policy_has_boost_freq(policy)) { 267 /* This gets disabled by core on driver unregister */ 268 ret = cpufreq_enable_boost_support(); 269 if (ret) 270 goto out_free_cpufreq_table; 271 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs; 272 } 273 274 transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev); 275 if (!transition_latency) 276 transition_latency = CPUFREQ_ETERNAL; 277 278 policy->cpuinfo.transition_latency = transition_latency; 279 policy->dvfs_possible_from_any_cpu = true; 280 281 dev_pm_opp_of_register_em(policy->cpus); 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_online(struct cpufreq_policy *policy) 301 { 302 /* We did light-weight tear down earlier, nothing to do here */ 303 return 0; 304 } 305 306 static int cpufreq_offline(struct cpufreq_policy *policy) 307 { 308 /* 309 * Preserve policy->driver_data and don't free resources on light-weight 310 * tear down. 311 */ 312 return 0; 313 } 314 315 static int cpufreq_exit(struct cpufreq_policy *policy) 316 { 317 struct private_data *priv = policy->driver_data; 318 319 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); 320 if (priv->have_static_opps) 321 dev_pm_opp_of_cpumask_remove_table(policy->related_cpus); 322 if (priv->reg_name) 323 dev_pm_opp_put_regulators(priv->opp_table); 324 325 clk_put(policy->clk); 326 kfree(priv); 327 328 return 0; 329 } 330 331 static struct cpufreq_driver dt_cpufreq_driver = { 332 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK | 333 CPUFREQ_IS_COOLING_DEV, 334 .verify = cpufreq_generic_frequency_table_verify, 335 .target_index = set_target, 336 .get = cpufreq_generic_get, 337 .init = cpufreq_init, 338 .exit = cpufreq_exit, 339 .online = cpufreq_online, 340 .offline = cpufreq_offline, 341 .name = "cpufreq-dt", 342 .attr = cpufreq_dt_attr, 343 .suspend = cpufreq_generic_suspend, 344 }; 345 346 static int dt_cpufreq_probe(struct platform_device *pdev) 347 { 348 struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev); 349 int ret; 350 351 /* 352 * All per-cluster (CPUs sharing clock/voltages) initialization is done 353 * from ->init(). In probe(), we just need to make sure that clk and 354 * regulators are available. Else defer probe and retry. 355 * 356 * FIXME: Is checking this only for CPU0 sufficient ? 357 */ 358 ret = resources_available(); 359 if (ret) 360 return ret; 361 362 if (data) { 363 if (data->have_governor_per_policy) 364 dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY; 365 366 dt_cpufreq_driver.resume = data->resume; 367 if (data->suspend) 368 dt_cpufreq_driver.suspend = data->suspend; 369 } 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