1 // SPDX-License-Identifier: GPL-2.0-only
3 * RISC-V SBI CPU idle driver.
5 * Copyright (c) 2021 Western Digital Corporation or its affiliates.
6 * Copyright (c) 2022 Ventana Micro Systems Inc.
9 #define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt
11 #include <linux/cpuidle.h>
12 #include <linux/cpumask.h>
13 #include <linux/cpu_pm.h>
14 #include <linux/cpu_cooling.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
18 #include <linux/of_device.h>
19 #include <linux/slab.h>
20 #include <linux/platform_device.h>
21 #include <linux/pm_domain.h>
22 #include <linux/pm_runtime.h>
23 #include <asm/cpuidle.h>
26 #include <asm/suspend.h>
28 #include "dt_idle_states.h"
29 #include "dt_idle_genpd.h"
31 struct sbi_cpuidle_data {
36 struct sbi_domain_state {
41 static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
42 static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
43 static bool sbi_cpuidle_use_osi;
44 static bool sbi_cpuidle_use_cpuhp;
45 static bool sbi_cpuidle_pd_allow_domain_state;
47 static inline void sbi_set_domain_state(u32 state)
49 struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
51 data->available = true;
55 static inline u32 sbi_get_domain_state(void)
57 struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
62 static inline void sbi_clear_domain_state(void)
64 struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
66 data->available = false;
69 static inline bool sbi_is_domain_state_available(void)
71 struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
73 return data->available;
76 static int sbi_suspend_finisher(unsigned long suspend_type,
77 unsigned long resume_addr,
82 ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
83 suspend_type, resume_addr, opaque, 0, 0, 0);
85 return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
88 static int sbi_suspend(u32 state)
90 if (state & SBI_HSM_SUSP_NON_RET_BIT)
91 return cpu_suspend(state, sbi_suspend_finisher);
93 return sbi_suspend_finisher(state, 0, 0);
96 static int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
97 struct cpuidle_driver *drv, int idx)
99 u32 *states = __this_cpu_read(sbi_cpuidle_data.states);
100 u32 state = states[idx];
102 if (state & SBI_HSM_SUSP_NON_RET_BIT)
103 return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, state);
105 return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(sbi_suspend,
109 static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
110 struct cpuidle_driver *drv, int idx,
113 struct sbi_cpuidle_data *data = this_cpu_ptr(&sbi_cpuidle_data);
114 u32 *states = data->states;
115 struct device *pd_dev = data->dev;
119 ret = cpu_pm_enter();
123 /* Do runtime PM to manage a hierarchical CPU toplogy. */
124 ct_irq_enter_irqson();
126 dev_pm_genpd_suspend(pd_dev);
128 pm_runtime_put_sync_suspend(pd_dev);
129 ct_irq_exit_irqson();
131 if (sbi_is_domain_state_available())
132 state = sbi_get_domain_state();
136 ret = sbi_suspend(state) ? -1 : idx;
138 ct_irq_enter_irqson();
140 dev_pm_genpd_resume(pd_dev);
142 pm_runtime_get_sync(pd_dev);
143 ct_irq_exit_irqson();
147 /* Clear the domain state to start fresh when back from idle. */
148 sbi_clear_domain_state();
152 static int sbi_enter_domain_idle_state(struct cpuidle_device *dev,
153 struct cpuidle_driver *drv, int idx)
155 return __sbi_enter_domain_idle_state(dev, drv, idx, false);
158 static int sbi_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
159 struct cpuidle_driver *drv,
162 return __sbi_enter_domain_idle_state(dev, drv, idx, true);
165 static int sbi_cpuidle_cpuhp_up(unsigned int cpu)
167 struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
170 pm_runtime_get_sync(pd_dev);
175 static int sbi_cpuidle_cpuhp_down(unsigned int cpu)
177 struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
180 pm_runtime_put_sync(pd_dev);
181 /* Clear domain state to start fresh at next online. */
182 sbi_clear_domain_state();
188 static void sbi_idle_init_cpuhp(void)
192 if (!sbi_cpuidle_use_cpuhp)
195 err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
196 "cpuidle/sbi:online",
197 sbi_cpuidle_cpuhp_up,
198 sbi_cpuidle_cpuhp_down);
200 pr_warn("Failed %d while setup cpuhp state\n", err);
203 static const struct of_device_id sbi_cpuidle_state_match[] = {
204 { .compatible = "riscv,idle-state",
205 .data = sbi_cpuidle_enter_state },
209 static bool sbi_suspend_state_is_valid(u32 state)
211 if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
212 state < SBI_HSM_SUSPEND_RET_PLATFORM)
214 if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
215 state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
220 static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
222 int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);
225 pr_warn("%pOF missing riscv,sbi-suspend-param property\n", np);
229 if (!sbi_suspend_state_is_valid(*state)) {
230 pr_warn("Invalid SBI suspend state %#x\n", *state);
237 static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
238 struct sbi_cpuidle_data *data,
239 unsigned int state_count, int cpu)
241 /* Currently limit the hierarchical topology to be used in OSI mode. */
242 if (!sbi_cpuidle_use_osi)
245 data->dev = dt_idle_attach_cpu(cpu, "sbi");
246 if (IS_ERR_OR_NULL(data->dev))
247 return PTR_ERR_OR_ZERO(data->dev);
250 * Using the deepest state for the CPU to trigger a potential selection
251 * of a shared state for the domain, assumes the domain states are all
254 drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;
255 drv->states[state_count - 1].enter_s2idle =
256 sbi_enter_s2idle_domain_idle_state;
257 sbi_cpuidle_use_cpuhp = true;
262 static int sbi_cpuidle_dt_init_states(struct device *dev,
263 struct cpuidle_driver *drv,
265 unsigned int state_count)
267 struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
268 struct device_node *state_node;
269 struct device_node *cpu_node;
273 cpu_node = of_cpu_device_node_get(cpu);
277 states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);
283 /* Parse SBI specific details from state DT nodes */
284 for (i = 1; i < state_count; i++) {
285 state_node = of_get_cpu_state_node(cpu_node, i - 1);
289 ret = sbi_dt_parse_state_node(state_node, &states[i]);
290 of_node_put(state_node);
295 pr_debug("sbi-state %#x index %d\n", states[i], i);
297 if (i != state_count) {
302 /* Initialize optional data, used for the hierarchical topology. */
303 ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu);
307 /* Store states in the per-cpu struct. */
308 data->states = states;
311 of_node_put(cpu_node);
316 static void sbi_cpuidle_deinit_cpu(int cpu)
318 struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
320 dt_idle_detach_cpu(data->dev);
321 sbi_cpuidle_use_cpuhp = false;
324 static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
326 struct cpuidle_driver *drv;
327 unsigned int state_count = 0;
330 drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
334 drv->name = "sbi_cpuidle";
335 drv->owner = THIS_MODULE;
336 drv->cpumask = (struct cpumask *)cpumask_of(cpu);
338 /* RISC-V architectural WFI to be represented as state index 0. */
339 drv->states[0].enter = sbi_cpuidle_enter_state;
340 drv->states[0].exit_latency = 1;
341 drv->states[0].target_residency = 1;
342 drv->states[0].power_usage = UINT_MAX;
343 strcpy(drv->states[0].name, "WFI");
344 strcpy(drv->states[0].desc, "RISC-V WFI");
347 * If no DT idle states are detected (ret == 0) let the driver
348 * initialization fail accordingly since there is no reason to
349 * initialize the idle driver if only wfi is supported, the
350 * default archictectural back-end already executes wfi
353 ret = dt_init_idle_driver(drv, sbi_cpuidle_state_match, 1);
355 pr_debug("HART%ld: failed to parse DT idle states\n",
356 cpuid_to_hartid_map(cpu));
357 return ret ? : -ENODEV;
359 state_count = ret + 1; /* Include WFI state as well */
361 /* Initialize idle states from DT. */
362 ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);
364 pr_err("HART%ld: failed to init idle states\n",
365 cpuid_to_hartid_map(cpu));
369 ret = cpuidle_register(drv, NULL);
373 cpuidle_cooling_register(drv);
377 sbi_cpuidle_deinit_cpu(cpu);
381 static void sbi_cpuidle_domain_sync_state(struct device *dev)
384 * All devices have now been attached/probed to the PM domain
385 * topology, hence it's fine to allow domain states to be picked.
387 sbi_cpuidle_pd_allow_domain_state = true;
390 #ifdef CONFIG_DT_IDLE_GENPD
392 static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
394 struct genpd_power_state *state = &pd->states[pd->state_idx];
400 if (!sbi_cpuidle_pd_allow_domain_state)
403 /* OSI mode is enabled, set the corresponding domain state. */
404 pd_state = state->data;
405 sbi_set_domain_state(*pd_state);
410 struct sbi_pd_provider {
411 struct list_head link;
412 struct device_node *node;
415 static LIST_HEAD(sbi_pd_providers);
417 static int sbi_pd_init(struct device_node *np)
419 struct generic_pm_domain *pd;
420 struct sbi_pd_provider *pd_provider;
421 struct dev_power_governor *pd_gov;
424 pd = dt_idle_pd_alloc(np, sbi_dt_parse_state_node);
428 pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
432 pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
434 /* Allow power off when OSI is available. */
435 if (sbi_cpuidle_use_osi)
436 pd->power_off = sbi_cpuidle_pd_power_off;
438 pd->flags |= GENPD_FLAG_ALWAYS_ON;
440 /* Use governor for CPU PM domains if it has some states to manage. */
441 pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;
443 ret = pm_genpd_init(pd, pd_gov, false);
447 ret = of_genpd_add_provider_simple(np, pd);
451 pd_provider->node = of_node_get(np);
452 list_add(&pd_provider->link, &sbi_pd_providers);
454 pr_debug("init PM domain %s\n", pd->name);
464 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
468 static void sbi_pd_remove(void)
470 struct sbi_pd_provider *pd_provider, *it;
471 struct generic_pm_domain *genpd;
473 list_for_each_entry_safe(pd_provider, it, &sbi_pd_providers, link) {
474 of_genpd_del_provider(pd_provider->node);
476 genpd = of_genpd_remove_last(pd_provider->node);
480 of_node_put(pd_provider->node);
481 list_del(&pd_provider->link);
486 static int sbi_genpd_probe(struct device_node *np)
488 struct device_node *node;
489 int ret = 0, pd_count = 0;
495 * Parse child nodes for the "#power-domain-cells" property and
496 * initialize a genpd/genpd-of-provider pair when it's found.
498 for_each_child_of_node(np, node) {
499 if (!of_find_property(node, "#power-domain-cells", NULL))
502 ret = sbi_pd_init(node);
509 /* Bail out if not using the hierarchical CPU topology. */
513 /* Link genpd masters/subdomains to model the CPU topology. */
514 ret = dt_idle_pd_init_topology(np);
524 pr_err("failed to create CPU PM domains ret=%d\n", ret);
531 static inline int sbi_genpd_probe(struct device_node *np)
538 static int sbi_cpuidle_probe(struct platform_device *pdev)
541 struct cpuidle_driver *drv;
542 struct cpuidle_device *dev;
543 struct device_node *np, *pds_node;
545 /* Detect OSI support based on CPU DT nodes */
546 sbi_cpuidle_use_osi = true;
547 for_each_possible_cpu(cpu) {
548 np = of_cpu_device_node_get(cpu);
550 of_find_property(np, "power-domains", NULL) &&
551 of_find_property(np, "power-domain-names", NULL)) {
554 sbi_cpuidle_use_osi = false;
559 /* Populate generic power domains from DT nodes */
560 pds_node = of_find_node_by_path("/cpus/power-domains");
562 ret = sbi_genpd_probe(pds_node);
563 of_node_put(pds_node);
568 /* Initialize CPU idle driver for each CPU */
569 for_each_possible_cpu(cpu) {
570 ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
572 pr_debug("HART%ld: idle driver init failed\n",
573 cpuid_to_hartid_map(cpu));
578 /* Setup CPU hotplut notifiers */
579 sbi_idle_init_cpuhp();
581 pr_info("idle driver registered for all CPUs\n");
587 dev = per_cpu(cpuidle_devices, cpu);
588 drv = cpuidle_get_cpu_driver(dev);
589 cpuidle_unregister(drv);
590 sbi_cpuidle_deinit_cpu(cpu);
596 static struct platform_driver sbi_cpuidle_driver = {
597 .probe = sbi_cpuidle_probe,
599 .name = "sbi-cpuidle",
600 .sync_state = sbi_cpuidle_domain_sync_state,
604 static int __init sbi_cpuidle_init(void)
607 struct platform_device *pdev;
610 * The SBI HSM suspend function is only available when:
611 * 1) SBI version is 0.3 or higher
612 * 2) SBI HSM extension is available
614 if ((sbi_spec_version < sbi_mk_version(0, 3)) ||
615 sbi_probe_extension(SBI_EXT_HSM) <= 0) {
616 pr_info("HSM suspend not available\n");
620 ret = platform_driver_register(&sbi_cpuidle_driver);
624 pdev = platform_device_register_simple("sbi-cpuidle",
627 platform_driver_unregister(&sbi_cpuidle_driver);
628 return PTR_ERR(pdev);
633 device_initcall(sbi_cpuidle_init);