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 unsigned long min_uV = ~0, max_uV = 0; 200 unsigned int transition_latency; 201 bool need_update = false; 202 int ret; 203 204 ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk); 205 if (ret) { 206 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret); 207 return ret; 208 } 209 210 np = of_node_get(cpu_dev->of_node); 211 if (!np) { 212 dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu); 213 ret = -ENOENT; 214 goto out_put_reg_clk; 215 } 216 217 /* Get OPP-sharing information from "operating-points-v2" bindings */ 218 ret = of_get_cpus_sharing_opps(cpu_dev, policy->cpus); 219 if (ret) { 220 /* 221 * operating-points-v2 not supported, fallback to old method of 222 * finding shared-OPPs for backward compatibility. 223 */ 224 if (ret == -ENOENT) 225 need_update = true; 226 else 227 goto out_node_put; 228 } 229 230 /* 231 * Initialize OPP tables for all policy->cpus. They will be shared by 232 * all CPUs which have marked their CPUs shared with OPP bindings. 233 * 234 * For platforms not using operating-points-v2 bindings, we do this 235 * before updating policy->cpus. Otherwise, we will end up creating 236 * duplicate OPPs for policy->cpus. 237 * 238 * OPPs might be populated at runtime, don't check for error here 239 */ 240 of_cpumask_init_opp_table(policy->cpus); 241 242 if (need_update) { 243 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data(); 244 245 if (!pd || !pd->independent_clocks) 246 cpumask_setall(policy->cpus); 247 248 /* 249 * OPP tables are initialized only for policy->cpu, do it for 250 * others as well. 251 */ 252 set_cpus_sharing_opps(cpu_dev, policy->cpus); 253 254 of_property_read_u32(np, "clock-latency", &transition_latency); 255 } else { 256 transition_latency = dev_pm_opp_get_max_clock_latency(cpu_dev); 257 } 258 259 /* 260 * But we need OPP table to function so if it is not there let's 261 * give platform code chance to provide it for us. 262 */ 263 ret = dev_pm_opp_get_opp_count(cpu_dev); 264 if (ret <= 0) { 265 pr_debug("OPP table is not ready, deferring probe\n"); 266 ret = -EPROBE_DEFER; 267 goto out_free_opp; 268 } 269 270 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 271 if (!priv) { 272 ret = -ENOMEM; 273 goto out_free_opp; 274 } 275 276 of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance); 277 278 if (!transition_latency) 279 transition_latency = CPUFREQ_ETERNAL; 280 281 if (!IS_ERR(cpu_reg)) { 282 unsigned long opp_freq = 0; 283 284 /* 285 * Disable any OPPs where the connected regulator isn't able to 286 * provide the specified voltage and record minimum and maximum 287 * voltage levels. 288 */ 289 while (1) { 290 struct dev_pm_opp *opp; 291 unsigned long opp_uV, tol_uV; 292 293 rcu_read_lock(); 294 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq); 295 if (IS_ERR(opp)) { 296 rcu_read_unlock(); 297 break; 298 } 299 opp_uV = dev_pm_opp_get_voltage(opp); 300 rcu_read_unlock(); 301 302 tol_uV = opp_uV * priv->voltage_tolerance / 100; 303 if (regulator_is_supported_voltage(cpu_reg, opp_uV, 304 opp_uV + tol_uV)) { 305 if (opp_uV < min_uV) 306 min_uV = opp_uV; 307 if (opp_uV > max_uV) 308 max_uV = opp_uV; 309 } else { 310 dev_pm_opp_disable(cpu_dev, opp_freq); 311 } 312 313 opp_freq++; 314 } 315 316 ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV); 317 if (ret > 0) 318 transition_latency += ret * 1000; 319 } 320 321 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); 322 if (ret) { 323 pr_err("failed to init cpufreq table: %d\n", ret); 324 goto out_free_priv; 325 } 326 327 priv->cpu_dev = cpu_dev; 328 priv->cpu_reg = cpu_reg; 329 policy->driver_data = priv; 330 331 policy->clk = cpu_clk; 332 ret = cpufreq_table_validate_and_show(policy, freq_table); 333 if (ret) { 334 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__, 335 ret); 336 goto out_free_cpufreq_table; 337 } 338 339 /* Support turbo/boost mode */ 340 if (policy_has_boost_freq(policy)) { 341 /* This gets disabled by core on driver unregister */ 342 ret = cpufreq_enable_boost_support(); 343 if (ret) 344 goto out_free_cpufreq_table; 345 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs; 346 } 347 348 policy->cpuinfo.transition_latency = transition_latency; 349 350 of_node_put(np); 351 352 return 0; 353 354 out_free_cpufreq_table: 355 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); 356 out_free_priv: 357 kfree(priv); 358 out_free_opp: 359 of_cpumask_free_opp_table(policy->cpus); 360 out_node_put: 361 of_node_put(np); 362 out_put_reg_clk: 363 clk_put(cpu_clk); 364 if (!IS_ERR(cpu_reg)) 365 regulator_put(cpu_reg); 366 367 return ret; 368 } 369 370 static int cpufreq_exit(struct cpufreq_policy *policy) 371 { 372 struct private_data *priv = policy->driver_data; 373 374 cpufreq_cooling_unregister(priv->cdev); 375 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); 376 of_cpumask_free_opp_table(policy->related_cpus); 377 clk_put(policy->clk); 378 if (!IS_ERR(priv->cpu_reg)) 379 regulator_put(priv->cpu_reg); 380 kfree(priv); 381 382 return 0; 383 } 384 385 static void cpufreq_ready(struct cpufreq_policy *policy) 386 { 387 struct private_data *priv = policy->driver_data; 388 struct device_node *np = of_node_get(priv->cpu_dev->of_node); 389 390 if (WARN_ON(!np)) 391 return; 392 393 /* 394 * For now, just loading the cooling device; 395 * thermal DT code takes care of matching them. 396 */ 397 if (of_find_property(np, "#cooling-cells", NULL)) { 398 priv->cdev = of_cpufreq_cooling_register(np, 399 policy->related_cpus); 400 if (IS_ERR(priv->cdev)) { 401 dev_err(priv->cpu_dev, 402 "running cpufreq without cooling device: %ld\n", 403 PTR_ERR(priv->cdev)); 404 405 priv->cdev = NULL; 406 } 407 } 408 409 of_node_put(np); 410 } 411 412 static struct cpufreq_driver dt_cpufreq_driver = { 413 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, 414 .verify = cpufreq_generic_frequency_table_verify, 415 .target_index = set_target, 416 .get = cpufreq_generic_get, 417 .init = cpufreq_init, 418 .exit = cpufreq_exit, 419 .ready = cpufreq_ready, 420 .name = "cpufreq-dt", 421 .attr = cpufreq_dt_attr, 422 }; 423 424 static int dt_cpufreq_probe(struct platform_device *pdev) 425 { 426 struct device *cpu_dev; 427 struct regulator *cpu_reg; 428 struct clk *cpu_clk; 429 int ret; 430 431 /* 432 * All per-cluster (CPUs sharing clock/voltages) initialization is done 433 * from ->init(). In probe(), we just need to make sure that clk and 434 * regulators are available. Else defer probe and retry. 435 * 436 * FIXME: Is checking this only for CPU0 sufficient ? 437 */ 438 ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk); 439 if (ret) 440 return ret; 441 442 clk_put(cpu_clk); 443 if (!IS_ERR(cpu_reg)) 444 regulator_put(cpu_reg); 445 446 dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev); 447 448 ret = cpufreq_register_driver(&dt_cpufreq_driver); 449 if (ret) 450 dev_err(cpu_dev, "failed register driver: %d\n", ret); 451 452 return ret; 453 } 454 455 static int dt_cpufreq_remove(struct platform_device *pdev) 456 { 457 cpufreq_unregister_driver(&dt_cpufreq_driver); 458 return 0; 459 } 460 461 static struct platform_driver dt_cpufreq_platdrv = { 462 .driver = { 463 .name = "cpufreq-dt", 464 }, 465 .probe = dt_cpufreq_probe, 466 .remove = dt_cpufreq_remove, 467 }; 468 module_platform_driver(dt_cpufreq_platdrv); 469 470 MODULE_ALIAS("platform:cpufreq-dt"); 471 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); 472 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); 473 MODULE_DESCRIPTION("Generic cpufreq driver"); 474 MODULE_LICENSE("GPL"); 475