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 struct freq_attr *cpufreq_dt_attr[] = { 40 &cpufreq_freq_attr_scaling_available_freqs, 41 NULL, /* Extra space for boost-attr if required */ 42 NULL, 43 }; 44 45 static int set_target(struct cpufreq_policy *policy, unsigned int index) 46 { 47 struct dev_pm_opp *opp; 48 struct cpufreq_frequency_table *freq_table = policy->freq_table; 49 struct clk *cpu_clk = policy->clk; 50 struct private_data *priv = policy->driver_data; 51 struct device *cpu_dev = priv->cpu_dev; 52 struct regulator *cpu_reg = priv->cpu_reg; 53 unsigned long volt = 0, volt_old = 0, tol = 0; 54 unsigned int old_freq, new_freq; 55 long freq_Hz, freq_exact; 56 int ret; 57 58 freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000); 59 if (freq_Hz <= 0) 60 freq_Hz = freq_table[index].frequency * 1000; 61 62 freq_exact = freq_Hz; 63 new_freq = freq_Hz / 1000; 64 old_freq = clk_get_rate(cpu_clk) / 1000; 65 66 if (!IS_ERR(cpu_reg)) { 67 unsigned long opp_freq; 68 69 rcu_read_lock(); 70 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz); 71 if (IS_ERR(opp)) { 72 rcu_read_unlock(); 73 dev_err(cpu_dev, "failed to find OPP for %ld\n", 74 freq_Hz); 75 return PTR_ERR(opp); 76 } 77 volt = dev_pm_opp_get_voltage(opp); 78 opp_freq = dev_pm_opp_get_freq(opp); 79 rcu_read_unlock(); 80 tol = volt * priv->voltage_tolerance / 100; 81 volt_old = regulator_get_voltage(cpu_reg); 82 dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n", 83 opp_freq / 1000, volt); 84 } 85 86 dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n", 87 old_freq / 1000, (volt_old > 0) ? volt_old / 1000 : -1, 88 new_freq / 1000, volt ? volt / 1000 : -1); 89 90 /* scaling up? scale voltage before frequency */ 91 if (!IS_ERR(cpu_reg) && new_freq > old_freq) { 92 ret = regulator_set_voltage_tol(cpu_reg, volt, tol); 93 if (ret) { 94 dev_err(cpu_dev, "failed to scale voltage up: %d\n", 95 ret); 96 return ret; 97 } 98 } 99 100 ret = clk_set_rate(cpu_clk, freq_exact); 101 if (ret) { 102 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret); 103 if (!IS_ERR(cpu_reg) && volt_old > 0) 104 regulator_set_voltage_tol(cpu_reg, volt_old, tol); 105 return ret; 106 } 107 108 /* scaling down? scale voltage after frequency */ 109 if (!IS_ERR(cpu_reg) && new_freq < old_freq) { 110 ret = regulator_set_voltage_tol(cpu_reg, volt, tol); 111 if (ret) { 112 dev_err(cpu_dev, "failed to scale voltage down: %d\n", 113 ret); 114 clk_set_rate(cpu_clk, old_freq * 1000); 115 } 116 } 117 118 return ret; 119 } 120 121 static int allocate_resources(int cpu, struct device **cdev, 122 struct regulator **creg, struct clk **cclk) 123 { 124 struct device *cpu_dev; 125 struct regulator *cpu_reg; 126 struct clk *cpu_clk; 127 int ret = 0; 128 char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg; 129 130 cpu_dev = get_cpu_device(cpu); 131 if (!cpu_dev) { 132 pr_err("failed to get cpu%d device\n", cpu); 133 return -ENODEV; 134 } 135 136 /* Try "cpu0" for older DTs */ 137 if (!cpu) 138 reg = reg_cpu0; 139 else 140 reg = reg_cpu; 141 142 try_again: 143 cpu_reg = regulator_get_optional(cpu_dev, reg); 144 if (IS_ERR(cpu_reg)) { 145 /* 146 * If cpu's regulator supply node is present, but regulator is 147 * not yet registered, we should try defering probe. 148 */ 149 if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) { 150 dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n", 151 cpu); 152 return -EPROBE_DEFER; 153 } 154 155 /* Try with "cpu-supply" */ 156 if (reg == reg_cpu0) { 157 reg = reg_cpu; 158 goto try_again; 159 } 160 161 dev_dbg(cpu_dev, "no regulator for cpu%d: %ld\n", 162 cpu, PTR_ERR(cpu_reg)); 163 } 164 165 cpu_clk = clk_get(cpu_dev, NULL); 166 if (IS_ERR(cpu_clk)) { 167 /* put regulator */ 168 if (!IS_ERR(cpu_reg)) 169 regulator_put(cpu_reg); 170 171 ret = PTR_ERR(cpu_clk); 172 173 /* 174 * If cpu's clk node is present, but clock is not yet 175 * registered, we should try defering probe. 176 */ 177 if (ret == -EPROBE_DEFER) 178 dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu); 179 else 180 dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu, 181 ret); 182 } else { 183 *cdev = cpu_dev; 184 *creg = cpu_reg; 185 *cclk = cpu_clk; 186 } 187 188 return ret; 189 } 190 191 static int cpufreq_init(struct cpufreq_policy *policy) 192 { 193 struct cpufreq_frequency_table *freq_table; 194 struct device_node *np; 195 struct private_data *priv; 196 struct device *cpu_dev; 197 struct regulator *cpu_reg; 198 struct clk *cpu_clk; 199 struct dev_pm_opp *suspend_opp; 200 unsigned long min_uV = ~0, max_uV = 0; 201 unsigned int transition_latency; 202 bool need_update = false; 203 int ret; 204 205 ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk); 206 if (ret) { 207 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret); 208 return ret; 209 } 210 211 np = of_node_get(cpu_dev->of_node); 212 if (!np) { 213 dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu); 214 ret = -ENOENT; 215 goto out_put_reg_clk; 216 } 217 218 /* Get OPP-sharing information from "operating-points-v2" bindings */ 219 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus); 220 if (ret) { 221 /* 222 * operating-points-v2 not supported, fallback to old method of 223 * finding shared-OPPs for backward compatibility. 224 */ 225 if (ret == -ENOENT) 226 need_update = true; 227 else 228 goto out_node_put; 229 } 230 231 /* 232 * Initialize OPP tables for all policy->cpus. They will be shared by 233 * all CPUs which have marked their CPUs shared with OPP bindings. 234 * 235 * For platforms not using operating-points-v2 bindings, we do this 236 * before updating policy->cpus. Otherwise, we will end up creating 237 * duplicate OPPs for policy->cpus. 238 * 239 * OPPs might be populated at runtime, don't check for error here 240 */ 241 dev_pm_opp_of_cpumask_add_table(policy->cpus); 242 243 /* 244 * But we need OPP table to function so if it is not there let's 245 * give platform code chance to provide it for us. 246 */ 247 ret = dev_pm_opp_get_opp_count(cpu_dev); 248 if (ret <= 0) { 249 pr_debug("OPP table is not ready, deferring probe\n"); 250 ret = -EPROBE_DEFER; 251 goto out_free_opp; 252 } 253 254 if (need_update) { 255 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data(); 256 257 if (!pd || !pd->independent_clocks) 258 cpumask_setall(policy->cpus); 259 260 /* 261 * OPP tables are initialized only for policy->cpu, do it for 262 * others as well. 263 */ 264 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); 265 if (ret) 266 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", 267 __func__, ret); 268 269 of_property_read_u32(np, "clock-latency", &transition_latency); 270 } else { 271 transition_latency = dev_pm_opp_get_max_clock_latency(cpu_dev); 272 } 273 274 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 275 if (!priv) { 276 ret = -ENOMEM; 277 goto out_free_opp; 278 } 279 280 of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance); 281 282 if (!transition_latency) 283 transition_latency = CPUFREQ_ETERNAL; 284 285 if (!IS_ERR(cpu_reg)) { 286 unsigned long opp_freq = 0; 287 288 /* 289 * Disable any OPPs where the connected regulator isn't able to 290 * provide the specified voltage and record minimum and maximum 291 * voltage levels. 292 */ 293 while (1) { 294 struct dev_pm_opp *opp; 295 unsigned long opp_uV, tol_uV; 296 297 rcu_read_lock(); 298 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq); 299 if (IS_ERR(opp)) { 300 rcu_read_unlock(); 301 break; 302 } 303 opp_uV = dev_pm_opp_get_voltage(opp); 304 rcu_read_unlock(); 305 306 tol_uV = opp_uV * priv->voltage_tolerance / 100; 307 if (regulator_is_supported_voltage(cpu_reg, 308 opp_uV - tol_uV, 309 opp_uV + tol_uV)) { 310 if (opp_uV < min_uV) 311 min_uV = opp_uV; 312 if (opp_uV > max_uV) 313 max_uV = opp_uV; 314 } else { 315 dev_pm_opp_disable(cpu_dev, opp_freq); 316 } 317 318 opp_freq++; 319 } 320 321 ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV); 322 if (ret > 0) 323 transition_latency += ret * 1000; 324 } 325 326 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); 327 if (ret) { 328 pr_err("failed to init cpufreq table: %d\n", ret); 329 goto out_free_priv; 330 } 331 332 priv->cpu_dev = cpu_dev; 333 priv->cpu_reg = cpu_reg; 334 policy->driver_data = priv; 335 336 policy->clk = cpu_clk; 337 338 rcu_read_lock(); 339 suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev); 340 if (suspend_opp) 341 policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000; 342 rcu_read_unlock(); 343 344 ret = cpufreq_table_validate_and_show(policy, freq_table); 345 if (ret) { 346 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__, 347 ret); 348 goto out_free_cpufreq_table; 349 } 350 351 /* Support turbo/boost mode */ 352 if (policy_has_boost_freq(policy)) { 353 /* This gets disabled by core on driver unregister */ 354 ret = cpufreq_enable_boost_support(); 355 if (ret) 356 goto out_free_cpufreq_table; 357 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs; 358 } 359 360 policy->cpuinfo.transition_latency = transition_latency; 361 362 of_node_put(np); 363 364 return 0; 365 366 out_free_cpufreq_table: 367 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); 368 out_free_priv: 369 kfree(priv); 370 out_free_opp: 371 dev_pm_opp_of_cpumask_remove_table(policy->cpus); 372 out_node_put: 373 of_node_put(np); 374 out_put_reg_clk: 375 clk_put(cpu_clk); 376 if (!IS_ERR(cpu_reg)) 377 regulator_put(cpu_reg); 378 379 return ret; 380 } 381 382 static int cpufreq_exit(struct cpufreq_policy *policy) 383 { 384 struct private_data *priv = policy->driver_data; 385 386 cpufreq_cooling_unregister(priv->cdev); 387 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); 388 dev_pm_opp_of_cpumask_remove_table(policy->related_cpus); 389 clk_put(policy->clk); 390 if (!IS_ERR(priv->cpu_reg)) 391 regulator_put(priv->cpu_reg); 392 kfree(priv); 393 394 return 0; 395 } 396 397 static void cpufreq_ready(struct cpufreq_policy *policy) 398 { 399 struct private_data *priv = policy->driver_data; 400 struct device_node *np = of_node_get(priv->cpu_dev->of_node); 401 402 if (WARN_ON(!np)) 403 return; 404 405 /* 406 * For now, just loading the cooling device; 407 * thermal DT code takes care of matching them. 408 */ 409 if (of_find_property(np, "#cooling-cells", NULL)) { 410 priv->cdev = of_cpufreq_cooling_register(np, 411 policy->related_cpus); 412 if (IS_ERR(priv->cdev)) { 413 dev_err(priv->cpu_dev, 414 "running cpufreq without cooling device: %ld\n", 415 PTR_ERR(priv->cdev)); 416 417 priv->cdev = NULL; 418 } 419 } 420 421 of_node_put(np); 422 } 423 424 static struct cpufreq_driver dt_cpufreq_driver = { 425 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, 426 .verify = cpufreq_generic_frequency_table_verify, 427 .target_index = set_target, 428 .get = cpufreq_generic_get, 429 .init = cpufreq_init, 430 .exit = cpufreq_exit, 431 .ready = cpufreq_ready, 432 .name = "cpufreq-dt", 433 .attr = cpufreq_dt_attr, 434 .suspend = cpufreq_generic_suspend, 435 }; 436 437 static int dt_cpufreq_probe(struct platform_device *pdev) 438 { 439 struct device *cpu_dev; 440 struct regulator *cpu_reg; 441 struct clk *cpu_clk; 442 int ret; 443 444 /* 445 * All per-cluster (CPUs sharing clock/voltages) initialization is done 446 * from ->init(). In probe(), we just need to make sure that clk and 447 * regulators are available. Else defer probe and retry. 448 * 449 * FIXME: Is checking this only for CPU0 sufficient ? 450 */ 451 ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk); 452 if (ret) 453 return ret; 454 455 clk_put(cpu_clk); 456 if (!IS_ERR(cpu_reg)) 457 regulator_put(cpu_reg); 458 459 dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev); 460 461 ret = cpufreq_register_driver(&dt_cpufreq_driver); 462 if (ret) 463 dev_err(cpu_dev, "failed register driver: %d\n", ret); 464 465 return ret; 466 } 467 468 static int dt_cpufreq_remove(struct platform_device *pdev) 469 { 470 cpufreq_unregister_driver(&dt_cpufreq_driver); 471 return 0; 472 } 473 474 static struct platform_driver dt_cpufreq_platdrv = { 475 .driver = { 476 .name = "cpufreq-dt", 477 }, 478 .probe = dt_cpufreq_probe, 479 .remove = dt_cpufreq_remove, 480 }; 481 module_platform_driver(dt_cpufreq_platdrv); 482 483 MODULE_ALIAS("platform:cpufreq-dt"); 484 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); 485 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); 486 MODULE_DESCRIPTION("Generic cpufreq driver"); 487 MODULE_LICENSE("GPL"); 488