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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * RISC-V SBI CPU idle driver.4 *5 * Copyright (c) 2021 Western Digital Corporation or its affiliates.6 * Copyright (c) 2022 Ventana Micro Systems Inc.7 */8 9#define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt10 11#include <linux/cleanup.h>12#include <linux/cpuhotplug.h>13#include <linux/cpuidle.h>14#include <linux/cpumask.h>15#include <linux/cpu_pm.h>16#include <linux/cpu_cooling.h>17#include <linux/kernel.h>18#include <linux/module.h>19#include <linux/of.h>20#include <linux/slab.h>21#include <linux/platform_device.h>22#include <linux/pm_domain.h>23#include <linux/pm_runtime.h>24#include <asm/cpuidle.h>25#include <asm/sbi.h>26#include <asm/smp.h>27#include <asm/suspend.h>28 29#include "dt_idle_states.h"30#include "dt_idle_genpd.h"31 32struct sbi_cpuidle_data {33 u32 *states;34 struct device *dev;35};36 37struct sbi_domain_state {38 bool available;39 u32 state;40};41 42static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);43static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);44static bool sbi_cpuidle_use_osi;45static bool sbi_cpuidle_use_cpuhp;46static bool sbi_cpuidle_pd_allow_domain_state;47 48static inline void sbi_set_domain_state(u32 state)49{50 struct sbi_domain_state *data = this_cpu_ptr(&domain_state);51 52 data->available = true;53 data->state = state;54}55 56static inline u32 sbi_get_domain_state(void)57{58 struct sbi_domain_state *data = this_cpu_ptr(&domain_state);59 60 return data->state;61}62 63static inline void sbi_clear_domain_state(void)64{65 struct sbi_domain_state *data = this_cpu_ptr(&domain_state);66 67 data->available = false;68}69 70static inline bool sbi_is_domain_state_available(void)71{72 struct sbi_domain_state *data = this_cpu_ptr(&domain_state);73 74 return data->available;75}76 77static __cpuidle int sbi_cpuidle_enter_state(struct cpuidle_device *dev,78 struct cpuidle_driver *drv, int idx)79{80 u32 *states = __this_cpu_read(sbi_cpuidle_data.states);81 u32 state = states[idx];82 83 if (state & SBI_HSM_SUSP_NON_RET_BIT)84 return CPU_PM_CPU_IDLE_ENTER_PARAM(riscv_sbi_hart_suspend, idx, state);85 else86 return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(riscv_sbi_hart_suspend,87 idx, state);88}89 90static __cpuidle int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,91 struct cpuidle_driver *drv, int idx,92 bool s2idle)93{94 struct sbi_cpuidle_data *data = this_cpu_ptr(&sbi_cpuidle_data);95 u32 *states = data->states;96 struct device *pd_dev = data->dev;97 u32 state;98 int ret;99 100 ret = cpu_pm_enter();101 if (ret)102 return -1;103 104 /* Do runtime PM to manage a hierarchical CPU toplogy. */105 if (s2idle)106 dev_pm_genpd_suspend(pd_dev);107 else108 pm_runtime_put_sync_suspend(pd_dev);109 110 ct_cpuidle_enter();111 112 if (sbi_is_domain_state_available())113 state = sbi_get_domain_state();114 else115 state = states[idx];116 117 ret = riscv_sbi_hart_suspend(state) ? -1 : idx;118 119 ct_cpuidle_exit();120 121 if (s2idle)122 dev_pm_genpd_resume(pd_dev);123 else124 pm_runtime_get_sync(pd_dev);125 126 cpu_pm_exit();127 128 /* Clear the domain state to start fresh when back from idle. */129 sbi_clear_domain_state();130 return ret;131}132 133static int sbi_enter_domain_idle_state(struct cpuidle_device *dev,134 struct cpuidle_driver *drv, int idx)135{136 return __sbi_enter_domain_idle_state(dev, drv, idx, false);137}138 139static int sbi_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,140 struct cpuidle_driver *drv,141 int idx)142{143 return __sbi_enter_domain_idle_state(dev, drv, idx, true);144}145 146static int sbi_cpuidle_cpuhp_up(unsigned int cpu)147{148 struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);149 150 if (pd_dev)151 pm_runtime_get_sync(pd_dev);152 153 return 0;154}155 156static int sbi_cpuidle_cpuhp_down(unsigned int cpu)157{158 struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);159 160 if (pd_dev) {161 pm_runtime_put_sync(pd_dev);162 /* Clear domain state to start fresh at next online. */163 sbi_clear_domain_state();164 }165 166 return 0;167}168 169static void sbi_idle_init_cpuhp(void)170{171 int err;172 173 if (!sbi_cpuidle_use_cpuhp)174 return;175 176 err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,177 "cpuidle/sbi:online",178 sbi_cpuidle_cpuhp_up,179 sbi_cpuidle_cpuhp_down);180 if (err)181 pr_warn("Failed %d while setup cpuhp state\n", err);182}183 184static const struct of_device_id sbi_cpuidle_state_match[] = {185 { .compatible = "riscv,idle-state",186 .data = sbi_cpuidle_enter_state },187 { },188};189 190static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)191{192 int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);193 194 if (err) {195 pr_warn("%pOF missing riscv,sbi-suspend-param property\n", np);196 return err;197 }198 199 if (!riscv_sbi_suspend_state_is_valid(*state)) {200 pr_warn("Invalid SBI suspend state %#x\n", *state);201 return -EINVAL;202 }203 204 return 0;205}206 207static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,208 struct sbi_cpuidle_data *data,209 unsigned int state_count, int cpu)210{211 /* Currently limit the hierarchical topology to be used in OSI mode. */212 if (!sbi_cpuidle_use_osi)213 return 0;214 215 data->dev = dt_idle_attach_cpu(cpu, "sbi");216 if (IS_ERR_OR_NULL(data->dev))217 return PTR_ERR_OR_ZERO(data->dev);218 219 /*220 * Using the deepest state for the CPU to trigger a potential selection221 * of a shared state for the domain, assumes the domain states are all222 * deeper states.223 */224 drv->states[state_count - 1].flags |= CPUIDLE_FLAG_RCU_IDLE;225 drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;226 drv->states[state_count - 1].enter_s2idle =227 sbi_enter_s2idle_domain_idle_state;228 sbi_cpuidle_use_cpuhp = true;229 230 return 0;231}232 233static int sbi_cpuidle_dt_init_states(struct device *dev,234 struct cpuidle_driver *drv,235 unsigned int cpu,236 unsigned int state_count)237{238 struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);239 struct device_node *state_node;240 u32 *states;241 int i, ret;242 243 struct device_node *cpu_node __free(device_node) = of_cpu_device_node_get(cpu);244 if (!cpu_node)245 return -ENODEV;246 247 states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);248 if (!states)249 return -ENOMEM;250 251 /* Parse SBI specific details from state DT nodes */252 for (i = 1; i < state_count; i++) {253 state_node = of_get_cpu_state_node(cpu_node, i - 1);254 if (!state_node)255 break;256 257 ret = sbi_dt_parse_state_node(state_node, &states[i]);258 of_node_put(state_node);259 260 if (ret)261 return ret;262 263 pr_debug("sbi-state %#x index %d\n", states[i], i);264 }265 if (i != state_count)266 return -ENODEV;267 268 /* Initialize optional data, used for the hierarchical topology. */269 ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu);270 if (ret < 0)271 return ret;272 273 /* Store states in the per-cpu struct. */274 data->states = states;275 276 return 0;277}278 279static void sbi_cpuidle_deinit_cpu(int cpu)280{281 struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);282 283 dt_idle_detach_cpu(data->dev);284 sbi_cpuidle_use_cpuhp = false;285}286 287static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)288{289 struct cpuidle_driver *drv;290 unsigned int state_count = 0;291 int ret = 0;292 293 drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);294 if (!drv)295 return -ENOMEM;296 297 drv->name = "sbi_cpuidle";298 drv->owner = THIS_MODULE;299 drv->cpumask = (struct cpumask *)cpumask_of(cpu);300 301 /* RISC-V architectural WFI to be represented as state index 0. */302 drv->states[0].enter = sbi_cpuidle_enter_state;303 drv->states[0].exit_latency = 1;304 drv->states[0].target_residency = 1;305 drv->states[0].power_usage = UINT_MAX;306 strcpy(drv->states[0].name, "WFI");307 strcpy(drv->states[0].desc, "RISC-V WFI");308 309 /*310 * If no DT idle states are detected (ret == 0) let the driver311 * initialization fail accordingly since there is no reason to312 * initialize the idle driver if only wfi is supported, the313 * default archictectural back-end already executes wfi314 * on idle entry.315 */316 ret = dt_init_idle_driver(drv, sbi_cpuidle_state_match, 1);317 if (ret <= 0) {318 pr_debug("HART%ld: failed to parse DT idle states\n",319 cpuid_to_hartid_map(cpu));320 return ret ? : -ENODEV;321 }322 state_count = ret + 1; /* Include WFI state as well */323 324 /* Initialize idle states from DT. */325 ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);326 if (ret) {327 pr_err("HART%ld: failed to init idle states\n",328 cpuid_to_hartid_map(cpu));329 return ret;330 }331 332 ret = cpuidle_register(drv, NULL);333 if (ret)334 goto deinit;335 336 cpuidle_cooling_register(drv);337 338 return 0;339deinit:340 sbi_cpuidle_deinit_cpu(cpu);341 return ret;342}343 344static void sbi_cpuidle_domain_sync_state(struct device *dev)345{346 /*347 * All devices have now been attached/probed to the PM domain348 * topology, hence it's fine to allow domain states to be picked.349 */350 sbi_cpuidle_pd_allow_domain_state = true;351}352 353#ifdef CONFIG_DT_IDLE_GENPD354 355static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)356{357 struct genpd_power_state *state = &pd->states[pd->state_idx];358 u32 *pd_state;359 360 if (!state->data)361 return 0;362 363 if (!sbi_cpuidle_pd_allow_domain_state)364 return -EBUSY;365 366 /* OSI mode is enabled, set the corresponding domain state. */367 pd_state = state->data;368 sbi_set_domain_state(*pd_state);369 370 return 0;371}372 373struct sbi_pd_provider {374 struct list_head link;375 struct device_node *node;376};377 378static LIST_HEAD(sbi_pd_providers);379 380static int sbi_pd_init(struct device_node *np)381{382 struct generic_pm_domain *pd;383 struct sbi_pd_provider *pd_provider;384 struct dev_power_governor *pd_gov;385 int ret = -ENOMEM;386 387 pd = dt_idle_pd_alloc(np, sbi_dt_parse_state_node);388 if (!pd)389 goto out;390 391 pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);392 if (!pd_provider)393 goto free_pd;394 395 pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;396 397 /* Allow power off when OSI is available. */398 if (sbi_cpuidle_use_osi)399 pd->power_off = sbi_cpuidle_pd_power_off;400 else401 pd->flags |= GENPD_FLAG_ALWAYS_ON;402 403 /* Use governor for CPU PM domains if it has some states to manage. */404 pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;405 406 ret = pm_genpd_init(pd, pd_gov, false);407 if (ret)408 goto free_pd_prov;409 410 ret = of_genpd_add_provider_simple(np, pd);411 if (ret)412 goto remove_pd;413 414 pd_provider->node = of_node_get(np);415 list_add(&pd_provider->link, &sbi_pd_providers);416 417 pr_debug("init PM domain %s\n", pd->name);418 return 0;419 420remove_pd:421 pm_genpd_remove(pd);422free_pd_prov:423 kfree(pd_provider);424free_pd:425 dt_idle_pd_free(pd);426out:427 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);428 return ret;429}430 431static void sbi_pd_remove(void)432{433 struct sbi_pd_provider *pd_provider, *it;434 struct generic_pm_domain *genpd;435 436 list_for_each_entry_safe(pd_provider, it, &sbi_pd_providers, link) {437 of_genpd_del_provider(pd_provider->node);438 439 genpd = of_genpd_remove_last(pd_provider->node);440 if (!IS_ERR(genpd))441 kfree(genpd);442 443 of_node_put(pd_provider->node);444 list_del(&pd_provider->link);445 kfree(pd_provider);446 }447}448 449static int sbi_genpd_probe(struct device_node *np)450{451 int ret = 0, pd_count = 0;452 453 if (!np)454 return -ENODEV;455 456 /*457 * Parse child nodes for the "#power-domain-cells" property and458 * initialize a genpd/genpd-of-provider pair when it's found.459 */460 for_each_child_of_node_scoped(np, node) {461 if (!of_property_present(node, "#power-domain-cells"))462 continue;463 464 ret = sbi_pd_init(node);465 if (ret)466 goto remove_pd;467 468 pd_count++;469 }470 471 /* Bail out if not using the hierarchical CPU topology. */472 if (!pd_count)473 goto no_pd;474 475 /* Link genpd masters/subdomains to model the CPU topology. */476 ret = dt_idle_pd_init_topology(np);477 if (ret)478 goto remove_pd;479 480 return 0;481 482remove_pd:483 sbi_pd_remove();484 pr_err("failed to create CPU PM domains ret=%d\n", ret);485no_pd:486 return ret;487}488 489#else490 491static inline int sbi_genpd_probe(struct device_node *np)492{493 return 0;494}495 496#endif497 498static int sbi_cpuidle_probe(struct platform_device *pdev)499{500 int cpu, ret;501 struct cpuidle_driver *drv;502 struct cpuidle_device *dev;503 struct device_node *np, *pds_node;504 505 /* Detect OSI support based on CPU DT nodes */506 sbi_cpuidle_use_osi = true;507 for_each_possible_cpu(cpu) {508 np = of_cpu_device_node_get(cpu);509 if (np &&510 of_property_present(np, "power-domains") &&511 of_property_present(np, "power-domain-names")) {512 continue;513 } else {514 sbi_cpuidle_use_osi = false;515 break;516 }517 }518 519 /* Populate generic power domains from DT nodes */520 pds_node = of_find_node_by_path("/cpus/power-domains");521 if (pds_node) {522 ret = sbi_genpd_probe(pds_node);523 of_node_put(pds_node);524 if (ret)525 return ret;526 }527 528 /* Initialize CPU idle driver for each CPU */529 for_each_possible_cpu(cpu) {530 ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);531 if (ret) {532 pr_debug("HART%ld: idle driver init failed\n",533 cpuid_to_hartid_map(cpu));534 goto out_fail;535 }536 }537 538 /* Setup CPU hotplut notifiers */539 sbi_idle_init_cpuhp();540 541 pr_info("idle driver registered for all CPUs\n");542 543 return 0;544 545out_fail:546 while (--cpu >= 0) {547 dev = per_cpu(cpuidle_devices, cpu);548 drv = cpuidle_get_cpu_driver(dev);549 cpuidle_unregister(drv);550 sbi_cpuidle_deinit_cpu(cpu);551 }552 553 return ret;554}555 556static struct platform_driver sbi_cpuidle_driver = {557 .probe = sbi_cpuidle_probe,558 .driver = {559 .name = "sbi-cpuidle",560 .sync_state = sbi_cpuidle_domain_sync_state,561 },562};563 564static int __init sbi_cpuidle_init(void)565{566 int ret;567 struct platform_device *pdev;568 569 if (!riscv_sbi_hsm_is_supported())570 return 0;571 572 ret = platform_driver_register(&sbi_cpuidle_driver);573 if (ret)574 return ret;575 576 pdev = platform_device_register_simple("sbi-cpuidle",577 -1, NULL, 0);578 if (IS_ERR(pdev)) {579 platform_driver_unregister(&sbi_cpuidle_driver);580 return PTR_ERR(pdev);581 }582 583 return 0;584}585device_initcall(sbi_cpuidle_init);586