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/of_device.h> 20 #include <linux/platform_device.h> 21 #include <linux/psci.h> 22 #include <linux/pm_runtime.h> 23 #include <linux/slab.h> 24 #include <linux/string.h> 25 26 #include <asm/cpuidle.h> 27 28 #include "cpuidle-psci.h" 29 #include "dt_idle_states.h" 30 31 struct psci_cpuidle_data { 32 u32 *psci_states; 33 struct device *dev; 34 }; 35 36 static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data); 37 static DEFINE_PER_CPU(u32, domain_state); 38 static bool psci_cpuidle_use_cpuhp; 39 40 void psci_set_domain_state(u32 state) 41 { 42 __this_cpu_write(domain_state, state); 43 } 44 45 static inline u32 psci_get_domain_state(void) 46 { 47 return __this_cpu_read(domain_state); 48 } 49 50 static inline int psci_enter_state(int idx, u32 state) 51 { 52 return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, idx, state); 53 } 54 55 static int psci_enter_domain_idle_state(struct cpuidle_device *dev, 56 struct cpuidle_driver *drv, int idx) 57 { 58 struct psci_cpuidle_data *data = this_cpu_ptr(&psci_cpuidle_data); 59 u32 *states = data->psci_states; 60 struct device *pd_dev = data->dev; 61 u32 state; 62 int ret; 63 64 ret = cpu_pm_enter(); 65 if (ret) 66 return -1; 67 68 /* Do runtime PM to manage a hierarchical CPU toplogy. */ 69 pm_runtime_put_sync_suspend(pd_dev); 70 71 state = psci_get_domain_state(); 72 if (!state) 73 state = states[idx]; 74 75 ret = psci_cpu_suspend_enter(state) ? -1 : idx; 76 77 pm_runtime_get_sync(pd_dev); 78 79 cpu_pm_exit(); 80 81 /* Clear the domain state to start fresh when back from idle. */ 82 psci_set_domain_state(0); 83 return ret; 84 } 85 86 static int psci_idle_cpuhp_up(unsigned int cpu) 87 { 88 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); 89 90 if (pd_dev) 91 pm_runtime_get_sync(pd_dev); 92 93 return 0; 94 } 95 96 static int psci_idle_cpuhp_down(unsigned int cpu) 97 { 98 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); 99 100 if (pd_dev) { 101 pm_runtime_put_sync(pd_dev); 102 /* Clear domain state to start fresh at next online. */ 103 psci_set_domain_state(0); 104 } 105 106 return 0; 107 } 108 109 static void psci_idle_init_cpuhp(void) 110 { 111 int err; 112 113 if (!psci_cpuidle_use_cpuhp) 114 return; 115 116 err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING, 117 "cpuidle/psci:online", 118 psci_idle_cpuhp_up, 119 psci_idle_cpuhp_down); 120 if (err) 121 pr_warn("Failed %d while setup cpuhp state\n", err); 122 } 123 124 static int psci_enter_idle_state(struct cpuidle_device *dev, 125 struct cpuidle_driver *drv, int idx) 126 { 127 u32 *state = __this_cpu_read(psci_cpuidle_data.psci_states); 128 129 return psci_enter_state(idx, state[idx]); 130 } 131 132 static const struct of_device_id psci_idle_state_match[] = { 133 { .compatible = "arm,idle-state", 134 .data = psci_enter_idle_state }, 135 { }, 136 }; 137 138 int psci_dt_parse_state_node(struct device_node *np, u32 *state) 139 { 140 int err = of_property_read_u32(np, "arm,psci-suspend-param", state); 141 142 if (err) { 143 pr_warn("%pOF missing arm,psci-suspend-param property\n", np); 144 return err; 145 } 146 147 if (!psci_power_state_is_valid(*state)) { 148 pr_warn("Invalid PSCI power state %#x\n", *state); 149 return -EINVAL; 150 } 151 152 return 0; 153 } 154 155 static int psci_dt_cpu_init_topology(struct cpuidle_driver *drv, 156 struct psci_cpuidle_data *data, 157 unsigned int state_count, int cpu) 158 { 159 /* Currently limit the hierarchical topology to be used in OSI mode. */ 160 if (!psci_has_osi_support()) 161 return 0; 162 163 data->dev = psci_dt_attach_cpu(cpu); 164 if (IS_ERR_OR_NULL(data->dev)) 165 return PTR_ERR_OR_ZERO(data->dev); 166 167 /* 168 * Using the deepest state for the CPU to trigger a potential selection 169 * of a shared state for the domain, assumes the domain states are all 170 * deeper states. 171 */ 172 drv->states[state_count - 1].enter = psci_enter_domain_idle_state; 173 psci_cpuidle_use_cpuhp = true; 174 175 return 0; 176 } 177 178 static int psci_dt_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv, 179 struct device_node *cpu_node, 180 unsigned int state_count, int cpu) 181 { 182 int i, ret = 0; 183 u32 *psci_states; 184 struct device_node *state_node; 185 struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu); 186 187 state_count++; /* Add WFI state too */ 188 psci_states = devm_kcalloc(dev, state_count, sizeof(*psci_states), 189 GFP_KERNEL); 190 if (!psci_states) 191 return -ENOMEM; 192 193 for (i = 1; i < state_count; i++) { 194 state_node = of_get_cpu_state_node(cpu_node, i - 1); 195 if (!state_node) 196 break; 197 198 ret = psci_dt_parse_state_node(state_node, &psci_states[i]); 199 of_node_put(state_node); 200 201 if (ret) 202 return ret; 203 204 pr_debug("psci-power-state %#x index %d\n", psci_states[i], i); 205 } 206 207 if (i != state_count) 208 return -ENODEV; 209 210 /* Initialize optional data, used for the hierarchical topology. */ 211 ret = psci_dt_cpu_init_topology(drv, data, state_count, cpu); 212 if (ret < 0) 213 return ret; 214 215 /* Idle states parsed correctly, store them in the per-cpu struct. */ 216 data->psci_states = psci_states; 217 return 0; 218 } 219 220 static int psci_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv, 221 unsigned int cpu, unsigned int state_count) 222 { 223 struct device_node *cpu_node; 224 int ret; 225 226 /* 227 * If the PSCI cpu_suspend function hook has not been initialized 228 * idle states must not be enabled, so bail out 229 */ 230 if (!psci_ops.cpu_suspend) 231 return -EOPNOTSUPP; 232 233 cpu_node = of_cpu_device_node_get(cpu); 234 if (!cpu_node) 235 return -ENODEV; 236 237 ret = psci_dt_cpu_init_idle(dev, drv, cpu_node, state_count, cpu); 238 239 of_node_put(cpu_node); 240 241 return ret; 242 } 243 244 static void psci_cpu_deinit_idle(int cpu) 245 { 246 struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu); 247 248 psci_dt_detach_cpu(data->dev); 249 psci_cpuidle_use_cpuhp = false; 250 } 251 252 static int psci_idle_init_cpu(struct device *dev, int cpu) 253 { 254 struct cpuidle_driver *drv; 255 struct device_node *cpu_node; 256 const char *enable_method; 257 int ret = 0; 258 259 cpu_node = of_cpu_device_node_get(cpu); 260 if (!cpu_node) 261 return -ENODEV; 262 263 /* 264 * Check whether the enable-method for the cpu is PSCI, fail 265 * if it is not. 266 */ 267 enable_method = of_get_property(cpu_node, "enable-method", NULL); 268 if (!enable_method || (strcmp(enable_method, "psci"))) 269 ret = -ENODEV; 270 271 of_node_put(cpu_node); 272 if (ret) 273 return ret; 274 275 drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL); 276 if (!drv) 277 return -ENOMEM; 278 279 drv->name = "psci_idle"; 280 drv->owner = THIS_MODULE; 281 drv->cpumask = (struct cpumask *)cpumask_of(cpu); 282 283 /* 284 * PSCI idle states relies on architectural WFI to be represented as 285 * state index 0. 286 */ 287 drv->states[0].enter = psci_enter_idle_state; 288 drv->states[0].exit_latency = 1; 289 drv->states[0].target_residency = 1; 290 drv->states[0].power_usage = UINT_MAX; 291 strcpy(drv->states[0].name, "WFI"); 292 strcpy(drv->states[0].desc, "ARM WFI"); 293 294 /* 295 * If no DT idle states are detected (ret == 0) let the driver 296 * initialization fail accordingly since there is no reason to 297 * initialize the idle driver if only wfi is supported, the 298 * default archictectural back-end already executes wfi 299 * on idle entry. 300 */ 301 ret = dt_init_idle_driver(drv, psci_idle_state_match, 1); 302 if (ret <= 0) 303 return ret ? : -ENODEV; 304 305 /* 306 * Initialize PSCI idle states. 307 */ 308 ret = psci_cpu_init_idle(dev, drv, cpu, ret); 309 if (ret) { 310 pr_err("CPU %d failed to PSCI idle\n", cpu); 311 return ret; 312 } 313 314 ret = cpuidle_register(drv, NULL); 315 if (ret) 316 goto deinit; 317 318 cpuidle_cooling_register(drv); 319 320 return 0; 321 deinit: 322 psci_cpu_deinit_idle(cpu); 323 return ret; 324 } 325 326 /* 327 * psci_idle_probe - Initializes PSCI cpuidle driver 328 * 329 * Initializes PSCI cpuidle driver for all CPUs, if any CPU fails 330 * to register cpuidle driver then rollback to cancel all CPUs 331 * registration. 332 */ 333 static int psci_cpuidle_probe(struct platform_device *pdev) 334 { 335 int cpu, ret; 336 struct cpuidle_driver *drv; 337 struct cpuidle_device *dev; 338 339 for_each_possible_cpu(cpu) { 340 ret = psci_idle_init_cpu(&pdev->dev, cpu); 341 if (ret) 342 goto out_fail; 343 } 344 345 psci_idle_init_cpuhp(); 346 return 0; 347 348 out_fail: 349 while (--cpu >= 0) { 350 dev = per_cpu(cpuidle_devices, cpu); 351 drv = cpuidle_get_cpu_driver(dev); 352 cpuidle_unregister(drv); 353 psci_cpu_deinit_idle(cpu); 354 } 355 356 return ret; 357 } 358 359 static struct platform_driver psci_cpuidle_driver = { 360 .probe = psci_cpuidle_probe, 361 .driver = { 362 .name = "psci-cpuidle", 363 }, 364 }; 365 366 static int __init psci_idle_init(void) 367 { 368 struct platform_device *pdev; 369 int ret; 370 371 ret = platform_driver_register(&psci_cpuidle_driver); 372 if (ret) 373 return ret; 374 375 pdev = platform_device_register_simple("psci-cpuidle", -1, NULL, 0); 376 if (IS_ERR(pdev)) { 377 platform_driver_unregister(&psci_cpuidle_driver); 378 return PTR_ERR(pdev); 379 } 380 381 return 0; 382 } 383 device_initcall(psci_idle_init); 384