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/cpuidle.h> 13 #include <linux/cpumask.h> 14 #include <linux/cpu_pm.h> 15 #include <linux/kernel.h> 16 #include <linux/module.h> 17 #include <linux/of.h> 18 #include <linux/of_device.h> 19 #include <linux/psci.h> 20 #include <linux/pm_runtime.h> 21 #include <linux/slab.h> 22 23 #include <asm/cpuidle.h> 24 25 #include "cpuidle-psci.h" 26 #include "dt_idle_states.h" 27 28 struct psci_cpuidle_data { 29 u32 *psci_states; 30 struct device *dev; 31 }; 32 33 static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data); 34 static DEFINE_PER_CPU(u32, domain_state); 35 static bool psci_cpuidle_use_cpuhp __initdata; 36 37 void psci_set_domain_state(u32 state) 38 { 39 __this_cpu_write(domain_state, state); 40 } 41 42 static inline u32 psci_get_domain_state(void) 43 { 44 return __this_cpu_read(domain_state); 45 } 46 47 static inline int psci_enter_state(int idx, u32 state) 48 { 49 return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, idx, state); 50 } 51 52 static int psci_enter_domain_idle_state(struct cpuidle_device *dev, 53 struct cpuidle_driver *drv, int idx) 54 { 55 struct psci_cpuidle_data *data = this_cpu_ptr(&psci_cpuidle_data); 56 u32 *states = data->psci_states; 57 struct device *pd_dev = data->dev; 58 u32 state; 59 int ret; 60 61 /* Do runtime PM to manage a hierarchical CPU toplogy. */ 62 pm_runtime_put_sync_suspend(pd_dev); 63 64 state = psci_get_domain_state(); 65 if (!state) 66 state = states[idx]; 67 68 ret = psci_enter_state(idx, state); 69 70 pm_runtime_get_sync(pd_dev); 71 72 /* Clear the domain state to start fresh when back from idle. */ 73 psci_set_domain_state(0); 74 return ret; 75 } 76 77 static int psci_idle_cpuhp_up(unsigned int cpu) 78 { 79 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); 80 81 if (pd_dev) 82 pm_runtime_get_sync(pd_dev); 83 84 return 0; 85 } 86 87 static int psci_idle_cpuhp_down(unsigned int cpu) 88 { 89 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); 90 91 if (pd_dev) { 92 pm_runtime_put_sync(pd_dev); 93 /* Clear domain state to start fresh at next online. */ 94 psci_set_domain_state(0); 95 } 96 97 return 0; 98 } 99 100 static void __init psci_idle_init_cpuhp(void) 101 { 102 int err; 103 104 if (!psci_cpuidle_use_cpuhp) 105 return; 106 107 err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING, 108 "cpuidle/psci:online", 109 psci_idle_cpuhp_up, 110 psci_idle_cpuhp_down); 111 if (err) 112 pr_warn("Failed %d while setup cpuhp state\n", err); 113 } 114 115 static int psci_enter_idle_state(struct cpuidle_device *dev, 116 struct cpuidle_driver *drv, int idx) 117 { 118 u32 *state = __this_cpu_read(psci_cpuidle_data.psci_states); 119 120 return psci_enter_state(idx, state[idx]); 121 } 122 123 static struct cpuidle_driver psci_idle_driver __initdata = { 124 .name = "psci_idle", 125 .owner = THIS_MODULE, 126 /* 127 * PSCI idle states relies on architectural WFI to 128 * be represented as state index 0. 129 */ 130 .states[0] = { 131 .enter = psci_enter_idle_state, 132 .exit_latency = 1, 133 .target_residency = 1, 134 .power_usage = UINT_MAX, 135 .name = "WFI", 136 .desc = "ARM WFI", 137 } 138 }; 139 140 static const struct of_device_id psci_idle_state_match[] __initconst = { 141 { .compatible = "arm,idle-state", 142 .data = psci_enter_idle_state }, 143 { }, 144 }; 145 146 int __init psci_dt_parse_state_node(struct device_node *np, u32 *state) 147 { 148 int err = of_property_read_u32(np, "arm,psci-suspend-param", state); 149 150 if (err) { 151 pr_warn("%pOF missing arm,psci-suspend-param property\n", np); 152 return err; 153 } 154 155 if (!psci_power_state_is_valid(*state)) { 156 pr_warn("Invalid PSCI power state %#x\n", *state); 157 return -EINVAL; 158 } 159 160 return 0; 161 } 162 163 static int __init psci_dt_cpu_init_topology(struct cpuidle_driver *drv, 164 struct psci_cpuidle_data *data, 165 unsigned int state_count, int cpu) 166 { 167 /* Currently limit the hierarchical topology to be used in OSI mode. */ 168 if (!psci_has_osi_support()) 169 return 0; 170 171 data->dev = psci_dt_attach_cpu(cpu); 172 if (IS_ERR_OR_NULL(data->dev)) 173 return PTR_ERR_OR_ZERO(data->dev); 174 175 /* 176 * Using the deepest state for the CPU to trigger a potential selection 177 * of a shared state for the domain, assumes the domain states are all 178 * deeper states. 179 */ 180 drv->states[state_count - 1].enter = psci_enter_domain_idle_state; 181 psci_cpuidle_use_cpuhp = true; 182 183 return 0; 184 } 185 186 static int __init psci_dt_cpu_init_idle(struct cpuidle_driver *drv, 187 struct device_node *cpu_node, 188 unsigned int state_count, int cpu) 189 { 190 int i, ret = 0; 191 u32 *psci_states; 192 struct device_node *state_node; 193 struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu); 194 195 state_count++; /* Add WFI state too */ 196 psci_states = kcalloc(state_count, sizeof(*psci_states), GFP_KERNEL); 197 if (!psci_states) 198 return -ENOMEM; 199 200 for (i = 1; i < state_count; i++) { 201 state_node = of_get_cpu_state_node(cpu_node, i - 1); 202 if (!state_node) 203 break; 204 205 ret = psci_dt_parse_state_node(state_node, &psci_states[i]); 206 of_node_put(state_node); 207 208 if (ret) 209 goto free_mem; 210 211 pr_debug("psci-power-state %#x index %d\n", psci_states[i], i); 212 } 213 214 if (i != state_count) { 215 ret = -ENODEV; 216 goto free_mem; 217 } 218 219 /* Initialize optional data, used for the hierarchical topology. */ 220 ret = psci_dt_cpu_init_topology(drv, data, state_count, cpu); 221 if (ret < 0) 222 goto free_mem; 223 224 /* Idle states parsed correctly, store them in the per-cpu struct. */ 225 data->psci_states = psci_states; 226 return 0; 227 228 free_mem: 229 kfree(psci_states); 230 return ret; 231 } 232 233 static __init int psci_cpu_init_idle(struct cpuidle_driver *drv, 234 unsigned int cpu, unsigned int state_count) 235 { 236 struct device_node *cpu_node; 237 int ret; 238 239 /* 240 * If the PSCI cpu_suspend function hook has not been initialized 241 * idle states must not be enabled, so bail out 242 */ 243 if (!psci_ops.cpu_suspend) 244 return -EOPNOTSUPP; 245 246 cpu_node = of_cpu_device_node_get(cpu); 247 if (!cpu_node) 248 return -ENODEV; 249 250 ret = psci_dt_cpu_init_idle(drv, cpu_node, state_count, cpu); 251 252 of_node_put(cpu_node); 253 254 return ret; 255 } 256 257 static int __init psci_idle_init_cpu(int cpu) 258 { 259 struct cpuidle_driver *drv; 260 struct device_node *cpu_node; 261 const char *enable_method; 262 int ret = 0; 263 264 cpu_node = of_cpu_device_node_get(cpu); 265 if (!cpu_node) 266 return -ENODEV; 267 268 /* 269 * Check whether the enable-method for the cpu is PSCI, fail 270 * if it is not. 271 */ 272 enable_method = of_get_property(cpu_node, "enable-method", NULL); 273 if (!enable_method || (strcmp(enable_method, "psci"))) 274 ret = -ENODEV; 275 276 of_node_put(cpu_node); 277 if (ret) 278 return ret; 279 280 drv = kmemdup(&psci_idle_driver, sizeof(*drv), GFP_KERNEL); 281 if (!drv) 282 return -ENOMEM; 283 284 drv->cpumask = (struct cpumask *)cpumask_of(cpu); 285 286 /* 287 * Initialize idle states data, starting at index 1, since 288 * by default idle state 0 is the quiescent state reached 289 * by the cpu by executing the wfi instruction. 290 * 291 * If no DT idle states are detected (ret == 0) let the driver 292 * initialization fail accordingly since there is no reason to 293 * initialize the idle driver if only wfi is supported, the 294 * default archictectural back-end already executes wfi 295 * on idle entry. 296 */ 297 ret = dt_init_idle_driver(drv, psci_idle_state_match, 1); 298 if (ret <= 0) { 299 ret = ret ? : -ENODEV; 300 goto out_kfree_drv; 301 } 302 303 /* 304 * Initialize PSCI idle states. 305 */ 306 ret = psci_cpu_init_idle(drv, cpu, ret); 307 if (ret) { 308 pr_err("CPU %d failed to PSCI idle\n", cpu); 309 goto out_kfree_drv; 310 } 311 312 ret = cpuidle_register(drv, NULL); 313 if (ret) 314 goto out_kfree_drv; 315 316 return 0; 317 318 out_kfree_drv: 319 kfree(drv); 320 return ret; 321 } 322 323 /* 324 * psci_idle_init - Initializes PSCI cpuidle driver 325 * 326 * Initializes PSCI cpuidle driver for all CPUs, if any CPU fails 327 * to register cpuidle driver then rollback to cancel all CPUs 328 * registration. 329 */ 330 static int __init psci_idle_init(void) 331 { 332 int cpu, ret; 333 struct cpuidle_driver *drv; 334 struct cpuidle_device *dev; 335 336 for_each_possible_cpu(cpu) { 337 ret = psci_idle_init_cpu(cpu); 338 if (ret) 339 goto out_fail; 340 } 341 342 psci_idle_init_cpuhp(); 343 return 0; 344 345 out_fail: 346 while (--cpu >= 0) { 347 dev = per_cpu(cpuidle_devices, cpu); 348 drv = cpuidle_get_cpu_driver(dev); 349 cpuidle_unregister(drv); 350 kfree(drv); 351 } 352 353 return ret; 354 } 355 device_initcall(psci_idle_init); 356