1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * PSCI CPU idle driver. 4 * 5 * Copyright (C) 2019 ARM Ltd. 6 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> 7 */ 8 9 #define pr_fmt(fmt) "CPUidle PSCI: " fmt 10 11 #include <linux/cpuhotplug.h> 12 #include <linux/cpu_cooling.h> 13 #include <linux/cpuidle.h> 14 #include <linux/cpumask.h> 15 #include <linux/cpu_pm.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/of.h> 19 #include <linux/device/faux.h> 20 #include <linux/psci.h> 21 #include <linux/pm_domain.h> 22 #include <linux/pm_runtime.h> 23 #include <linux/slab.h> 24 #include <linux/string.h> 25 #include <linux/syscore_ops.h> 26 27 #include <asm/cpuidle.h> 28 #include <trace/events/power.h> 29 30 #include "cpuidle-psci.h" 31 #include "dt_idle_states.h" 32 #include "dt_idle_genpd.h" 33 34 struct psci_cpuidle_data { 35 u32 *psci_states; 36 struct device *dev; 37 }; 38 39 struct psci_cpuidle_domain_state { 40 struct generic_pm_domain *pd; 41 unsigned int state_idx; 42 u32 state; 43 }; 44 45 static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data); 46 static DEFINE_PER_CPU(struct psci_cpuidle_domain_state, psci_domain_state); 47 static bool psci_cpuidle_use_syscore; 48 49 void psci_set_domain_state(struct generic_pm_domain *pd, unsigned int state_idx, 50 u32 state) 51 { 52 struct psci_cpuidle_domain_state *ds = this_cpu_ptr(&psci_domain_state); 53 54 ds->pd = pd; 55 ds->state_idx = state_idx; 56 ds->state = state; 57 } 58 59 static inline void psci_clear_domain_state(void) 60 { 61 __this_cpu_write(psci_domain_state.state, 0); 62 } 63 64 static __cpuidle int __psci_enter_domain_idle_state(struct cpuidle_device *dev, 65 struct cpuidle_driver *drv, int idx, 66 bool s2idle) 67 { 68 struct psci_cpuidle_data *data = this_cpu_ptr(&psci_cpuidle_data); 69 u32 *states = data->psci_states; 70 struct device *pd_dev = data->dev; 71 struct psci_cpuidle_domain_state *ds; 72 u32 state = states[idx]; 73 int ret; 74 75 ret = cpu_pm_enter(); 76 if (ret) 77 return -1; 78 79 /* Do runtime PM to manage a hierarchical CPU toplogy. */ 80 if (s2idle) 81 dev_pm_genpd_suspend(pd_dev); 82 else 83 pm_runtime_put_sync_suspend(pd_dev); 84 85 ds = this_cpu_ptr(&psci_domain_state); 86 if (ds->state) 87 state = ds->state; 88 89 trace_psci_domain_idle_enter(dev->cpu, state, s2idle); 90 ret = psci_cpu_suspend_enter(state) ? -1 : idx; 91 trace_psci_domain_idle_exit(dev->cpu, state, s2idle); 92 93 if (s2idle) 94 dev_pm_genpd_resume(pd_dev); 95 else 96 pm_runtime_get_sync(pd_dev); 97 98 cpu_pm_exit(); 99 100 /* Correct domain-idlestate statistics if we failed to enter. */ 101 if (ret == -1 && ds->state) 102 pm_genpd_inc_rejected(ds->pd, ds->state_idx); 103 104 /* Clear the domain state to start fresh when back from idle. */ 105 psci_clear_domain_state(); 106 return ret; 107 } 108 109 static int psci_enter_domain_idle_state(struct cpuidle_device *dev, 110 struct cpuidle_driver *drv, int idx) 111 { 112 return __psci_enter_domain_idle_state(dev, drv, idx, false); 113 } 114 115 static int psci_enter_s2idle_domain_idle_state(struct cpuidle_device *dev, 116 struct cpuidle_driver *drv, 117 int idx) 118 { 119 return __psci_enter_domain_idle_state(dev, drv, idx, true); 120 } 121 122 static int psci_idle_cpuhp_up(unsigned int cpu) 123 { 124 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); 125 126 if (pd_dev) { 127 if (!IS_ENABLED(CONFIG_PREEMPT_RT)) 128 pm_runtime_get_sync(pd_dev); 129 else 130 dev_pm_genpd_resume(pd_dev); 131 } 132 133 return 0; 134 } 135 136 static int psci_idle_cpuhp_down(unsigned int cpu) 137 { 138 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); 139 140 if (pd_dev) { 141 if (!IS_ENABLED(CONFIG_PREEMPT_RT)) 142 pm_runtime_put_sync(pd_dev); 143 else 144 dev_pm_genpd_suspend(pd_dev); 145 146 /* Clear domain state to start fresh at next online. */ 147 psci_clear_domain_state(); 148 } 149 150 return 0; 151 } 152 153 static void psci_idle_syscore_switch(bool suspend) 154 { 155 bool cleared = false; 156 struct device *dev; 157 int cpu; 158 159 for_each_possible_cpu(cpu) { 160 dev = per_cpu_ptr(&psci_cpuidle_data, cpu)->dev; 161 162 if (dev && suspend) { 163 dev_pm_genpd_suspend(dev); 164 } else if (dev) { 165 dev_pm_genpd_resume(dev); 166 167 /* Account for userspace having offlined a CPU. */ 168 if (pm_runtime_status_suspended(dev)) 169 pm_runtime_set_active(dev); 170 171 /* Clear domain state to re-start fresh. */ 172 if (!cleared) { 173 psci_clear_domain_state(); 174 cleared = true; 175 } 176 } 177 } 178 } 179 180 static int psci_idle_syscore_suspend(void) 181 { 182 psci_idle_syscore_switch(true); 183 return 0; 184 } 185 186 static void psci_idle_syscore_resume(void) 187 { 188 psci_idle_syscore_switch(false); 189 } 190 191 static struct syscore_ops psci_idle_syscore_ops = { 192 .suspend = psci_idle_syscore_suspend, 193 .resume = psci_idle_syscore_resume, 194 }; 195 196 static void psci_idle_init_syscore(void) 197 { 198 if (psci_cpuidle_use_syscore) 199 register_syscore_ops(&psci_idle_syscore_ops); 200 } 201 202 static void psci_idle_init_cpuhp(void) 203 { 204 int err; 205 206 err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING, 207 "cpuidle/psci:online", 208 psci_idle_cpuhp_up, 209 psci_idle_cpuhp_down); 210 if (err) 211 pr_warn("Failed %d while setup cpuhp state\n", err); 212 } 213 214 static __cpuidle int psci_enter_idle_state(struct cpuidle_device *dev, 215 struct cpuidle_driver *drv, int idx) 216 { 217 u32 *state = __this_cpu_read(psci_cpuidle_data.psci_states); 218 219 return CPU_PM_CPU_IDLE_ENTER_PARAM_RCU(psci_cpu_suspend_enter, idx, state[idx]); 220 } 221 222 static const struct of_device_id psci_idle_state_match[] = { 223 { .compatible = "arm,idle-state", 224 .data = psci_enter_idle_state }, 225 { }, 226 }; 227 228 int psci_dt_parse_state_node(struct device_node *np, u32 *state) 229 { 230 int err = of_property_read_u32(np, "arm,psci-suspend-param", state); 231 232 if (err) { 233 pr_warn("%pOF missing arm,psci-suspend-param property\n", np); 234 return err; 235 } 236 237 if (!psci_power_state_is_valid(*state)) { 238 pr_warn("Invalid PSCI power state %#x\n", *state); 239 return -EINVAL; 240 } 241 242 return 0; 243 } 244 245 static int psci_dt_cpu_init_topology(struct cpuidle_driver *drv, 246 struct psci_cpuidle_data *data, 247 unsigned int state_count, int cpu) 248 { 249 /* Currently limit the hierarchical topology to be used in OSI mode. */ 250 if (!psci_has_osi_support()) 251 return 0; 252 253 data->dev = dt_idle_attach_cpu(cpu, "psci"); 254 if (IS_ERR_OR_NULL(data->dev)) 255 return PTR_ERR_OR_ZERO(data->dev); 256 257 psci_cpuidle_use_syscore = true; 258 259 /* 260 * Using the deepest state for the CPU to trigger a potential selection 261 * of a shared state for the domain, assumes the domain states are all 262 * deeper states. On PREEMPT_RT the hierarchical topology is limited to 263 * s2ram and s2idle. 264 */ 265 drv->states[state_count - 1].enter_s2idle = psci_enter_s2idle_domain_idle_state; 266 if (!IS_ENABLED(CONFIG_PREEMPT_RT)) 267 drv->states[state_count - 1].enter = psci_enter_domain_idle_state; 268 269 return 0; 270 } 271 272 static int psci_dt_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv, 273 struct device_node *cpu_node, 274 unsigned int state_count, int cpu) 275 { 276 int i, ret = 0; 277 u32 *psci_states; 278 struct device_node *state_node; 279 struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu); 280 281 state_count++; /* Add WFI state too */ 282 psci_states = devm_kcalloc(dev, state_count, sizeof(*psci_states), 283 GFP_KERNEL); 284 if (!psci_states) 285 return -ENOMEM; 286 287 for (i = 1; i < state_count; i++) { 288 state_node = of_get_cpu_state_node(cpu_node, i - 1); 289 if (!state_node) 290 break; 291 292 ret = psci_dt_parse_state_node(state_node, &psci_states[i]); 293 of_node_put(state_node); 294 295 if (ret) 296 return ret; 297 298 pr_debug("psci-power-state %#x index %d\n", psci_states[i], i); 299 } 300 301 if (i != state_count) 302 return -ENODEV; 303 304 /* Initialize optional data, used for the hierarchical topology. */ 305 ret = psci_dt_cpu_init_topology(drv, data, state_count, cpu); 306 if (ret < 0) 307 return ret; 308 309 /* Idle states parsed correctly, store them in the per-cpu struct. */ 310 data->psci_states = psci_states; 311 return 0; 312 } 313 314 static int psci_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv, 315 unsigned int cpu, unsigned int state_count) 316 { 317 struct device_node *cpu_node; 318 int ret; 319 320 /* 321 * If the PSCI cpu_suspend function hook has not been initialized 322 * idle states must not be enabled, so bail out 323 */ 324 if (!psci_ops.cpu_suspend) 325 return -EOPNOTSUPP; 326 327 cpu_node = of_cpu_device_node_get(cpu); 328 if (!cpu_node) 329 return -ENODEV; 330 331 ret = psci_dt_cpu_init_idle(dev, drv, cpu_node, state_count, cpu); 332 333 of_node_put(cpu_node); 334 335 return ret; 336 } 337 338 static void psci_cpu_deinit_idle(int cpu) 339 { 340 struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu); 341 342 dt_idle_detach_cpu(data->dev); 343 psci_cpuidle_use_syscore = false; 344 } 345 346 static int psci_idle_init_cpu(struct device *dev, int cpu) 347 { 348 struct cpuidle_driver *drv; 349 struct device_node *cpu_node; 350 const char *enable_method; 351 int ret = 0; 352 353 cpu_node = of_cpu_device_node_get(cpu); 354 if (!cpu_node) 355 return -ENODEV; 356 357 /* 358 * Check whether the enable-method for the cpu is PSCI, fail 359 * if it is not. 360 */ 361 enable_method = of_get_property(cpu_node, "enable-method", NULL); 362 if (!enable_method || (strcmp(enable_method, "psci"))) 363 ret = -ENODEV; 364 365 of_node_put(cpu_node); 366 if (ret) 367 return ret; 368 369 drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL); 370 if (!drv) 371 return -ENOMEM; 372 373 drv->name = "psci_idle"; 374 drv->owner = THIS_MODULE; 375 drv->cpumask = (struct cpumask *)cpumask_of(cpu); 376 377 /* 378 * PSCI idle states relies on architectural WFI to be represented as 379 * state index 0. 380 */ 381 drv->states[0].enter = psci_enter_idle_state; 382 drv->states[0].exit_latency = 1; 383 drv->states[0].target_residency = 1; 384 drv->states[0].power_usage = UINT_MAX; 385 strcpy(drv->states[0].name, "WFI"); 386 strcpy(drv->states[0].desc, "ARM WFI"); 387 388 /* 389 * If no DT idle states are detected (ret == 0) let the driver 390 * initialization fail accordingly since there is no reason to 391 * initialize the idle driver if only wfi is supported, the 392 * default archictectural back-end already executes wfi 393 * on idle entry. 394 */ 395 ret = dt_init_idle_driver(drv, psci_idle_state_match, 1); 396 if (ret <= 0) 397 return ret ? : -ENODEV; 398 399 /* 400 * Initialize PSCI idle states. 401 */ 402 ret = psci_cpu_init_idle(dev, drv, cpu, ret); 403 if (ret) { 404 pr_err("CPU %d failed to PSCI idle\n", cpu); 405 return ret; 406 } 407 408 ret = cpuidle_register(drv, NULL); 409 if (ret) 410 goto deinit; 411 412 cpuidle_cooling_register(drv); 413 414 return 0; 415 deinit: 416 psci_cpu_deinit_idle(cpu); 417 return ret; 418 } 419 420 /* 421 * psci_idle_probe - Initializes PSCI cpuidle driver 422 * 423 * Initializes PSCI cpuidle driver for all present CPUs, if any CPU fails 424 * to register cpuidle driver then rollback to cancel all CPUs 425 * registration. 426 */ 427 static int psci_cpuidle_probe(struct faux_device *fdev) 428 { 429 int cpu, ret; 430 struct cpuidle_driver *drv; 431 struct cpuidle_device *dev; 432 433 for_each_present_cpu(cpu) { 434 ret = psci_idle_init_cpu(&fdev->dev, cpu); 435 if (ret) 436 goto out_fail; 437 } 438 439 psci_idle_init_syscore(); 440 psci_idle_init_cpuhp(); 441 return 0; 442 443 out_fail: 444 while (--cpu >= 0) { 445 dev = per_cpu(cpuidle_devices, cpu); 446 drv = cpuidle_get_cpu_driver(dev); 447 cpuidle_unregister(drv); 448 psci_cpu_deinit_idle(cpu); 449 } 450 451 return ret; 452 } 453 454 static struct faux_device_ops psci_cpuidle_ops = { 455 .probe = psci_cpuidle_probe, 456 }; 457 458 static bool __init dt_idle_state_present(void) 459 { 460 struct device_node *cpu_node __free(device_node) = 461 of_cpu_device_node_get(cpumask_first(cpu_possible_mask)); 462 if (!cpu_node) 463 return false; 464 465 struct device_node *state_node __free(device_node) = 466 of_get_cpu_state_node(cpu_node, 0); 467 if (!state_node) 468 return false; 469 470 return !!of_match_node(psci_idle_state_match, state_node); 471 } 472 473 static int __init psci_idle_init(void) 474 { 475 struct faux_device *fdev; 476 477 if (!dt_idle_state_present()) 478 return 0; 479 480 fdev = faux_device_create("psci-cpuidle", NULL, &psci_cpuidle_ops); 481 if (!fdev) { 482 pr_err("Failed to create psci-cpuidle device\n"); 483 return -ENODEV; 484 } 485 486 return 0; 487 } 488 device_initcall(psci_idle_init); 489