1 // SPDX-License-Identifier: GPL-2.0-only
3 * PSCI CPU idle driver.
5 * Copyright (C) 2019 ARM Ltd.
6 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
9 #define pr_fmt(fmt) "CPUidle PSCI: " fmt
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>
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>
26 #include <asm/cpuidle.h>
28 #include "cpuidle-psci.h"
29 #include "dt_idle_states.h"
31 struct psci_cpuidle_data {
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;
40 void psci_set_domain_state(u32 state)
42 __this_cpu_write(domain_state, state);
45 static inline u32 psci_get_domain_state(void)
47 return __this_cpu_read(domain_state);
50 static inline int psci_enter_state(int idx, u32 state)
52 return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, idx, state);
55 static int psci_enter_domain_idle_state(struct cpuidle_device *dev,
56 struct cpuidle_driver *drv, int idx)
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;
68 /* Do runtime PM to manage a hierarchical CPU toplogy. */
69 RCU_NONIDLE(pm_runtime_put_sync_suspend(pd_dev));
71 state = psci_get_domain_state();
75 ret = psci_cpu_suspend_enter(state) ? -1 : idx;
77 RCU_NONIDLE(pm_runtime_get_sync(pd_dev));
81 /* Clear the domain state to start fresh when back from idle. */
82 psci_set_domain_state(0);
86 static int psci_idle_cpuhp_up(unsigned int cpu)
88 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);
91 pm_runtime_get_sync(pd_dev);
96 static int psci_idle_cpuhp_down(unsigned int cpu)
98 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);
101 pm_runtime_put_sync(pd_dev);
102 /* Clear domain state to start fresh at next online. */
103 psci_set_domain_state(0);
109 static void psci_idle_init_cpuhp(void)
113 if (!psci_cpuidle_use_cpuhp)
116 err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
117 "cpuidle/psci:online",
119 psci_idle_cpuhp_down);
121 pr_warn("Failed %d while setup cpuhp state\n", err);
124 static int psci_enter_idle_state(struct cpuidle_device *dev,
125 struct cpuidle_driver *drv, int idx)
127 u32 *state = __this_cpu_read(psci_cpuidle_data.psci_states);
129 return psci_enter_state(idx, state[idx]);
132 static const struct of_device_id psci_idle_state_match[] = {
133 { .compatible = "arm,idle-state",
134 .data = psci_enter_idle_state },
138 int psci_dt_parse_state_node(struct device_node *np, u32 *state)
140 int err = of_property_read_u32(np, "arm,psci-suspend-param", state);
143 pr_warn("%pOF missing arm,psci-suspend-param property\n", np);
147 if (!psci_power_state_is_valid(*state)) {
148 pr_warn("Invalid PSCI power state %#x\n", *state);
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)
159 /* Currently limit the hierarchical topology to be used in OSI mode. */
160 if (!psci_has_osi_support())
163 data->dev = psci_dt_attach_cpu(cpu);
164 if (IS_ERR_OR_NULL(data->dev))
165 return PTR_ERR_OR_ZERO(data->dev);
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
172 drv->states[state_count - 1].enter = psci_enter_domain_idle_state;
173 psci_cpuidle_use_cpuhp = true;
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)
184 struct device_node *state_node;
185 struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu);
187 state_count++; /* Add WFI state too */
188 psci_states = devm_kcalloc(dev, state_count, sizeof(*psci_states),
193 for (i = 1; i < state_count; i++) {
194 state_node = of_get_cpu_state_node(cpu_node, i - 1);
198 ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
199 of_node_put(state_node);
204 pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
207 if (i != state_count)
210 /* Initialize optional data, used for the hierarchical topology. */
211 ret = psci_dt_cpu_init_topology(drv, data, state_count, cpu);
215 /* Idle states parsed correctly, store them in the per-cpu struct. */
216 data->psci_states = psci_states;
220 static int psci_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv,
221 unsigned int cpu, unsigned int state_count)
223 struct device_node *cpu_node;
227 * If the PSCI cpu_suspend function hook has not been initialized
228 * idle states must not be enabled, so bail out
230 if (!psci_ops.cpu_suspend)
233 cpu_node = of_cpu_device_node_get(cpu);
237 ret = psci_dt_cpu_init_idle(dev, drv, cpu_node, state_count, cpu);
239 of_node_put(cpu_node);
244 static void psci_cpu_deinit_idle(int cpu)
246 struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu);
248 psci_dt_detach_cpu(data->dev);
249 psci_cpuidle_use_cpuhp = false;
252 static int psci_idle_init_cpu(struct device *dev, int cpu)
254 struct cpuidle_driver *drv;
255 struct device_node *cpu_node;
256 const char *enable_method;
259 cpu_node = of_cpu_device_node_get(cpu);
264 * Check whether the enable-method for the cpu is PSCI, fail
267 enable_method = of_get_property(cpu_node, "enable-method", NULL);
268 if (!enable_method || (strcmp(enable_method, "psci")))
271 of_node_put(cpu_node);
275 drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
279 drv->name = "psci_idle";
280 drv->owner = THIS_MODULE;
281 drv->cpumask = (struct cpumask *)cpumask_of(cpu);
284 * PSCI idle states relies on architectural WFI to be represented as
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");
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
301 ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
303 return ret ? : -ENODEV;
306 * Initialize PSCI idle states.
308 ret = psci_cpu_init_idle(dev, drv, cpu, ret);
310 pr_err("CPU %d failed to PSCI idle\n", cpu);
314 ret = cpuidle_register(drv, NULL);
318 cpuidle_cooling_register(drv);
322 psci_cpu_deinit_idle(cpu);
327 * psci_idle_probe - Initializes PSCI cpuidle driver
329 * Initializes PSCI cpuidle driver for all CPUs, if any CPU fails
330 * to register cpuidle driver then rollback to cancel all CPUs
333 static int psci_cpuidle_probe(struct platform_device *pdev)
336 struct cpuidle_driver *drv;
337 struct cpuidle_device *dev;
339 for_each_possible_cpu(cpu) {
340 ret = psci_idle_init_cpu(&pdev->dev, cpu);
345 psci_idle_init_cpuhp();
350 dev = per_cpu(cpuidle_devices, cpu);
351 drv = cpuidle_get_cpu_driver(dev);
352 cpuidle_unregister(drv);
353 psci_cpu_deinit_idle(cpu);
359 static struct platform_driver psci_cpuidle_driver = {
360 .probe = psci_cpuidle_probe,
362 .name = "psci-cpuidle",
366 static int __init psci_idle_init(void)
368 struct platform_device *pdev;
371 ret = platform_driver_register(&psci_cpuidle_driver);
375 pdev = platform_device_register_simple("psci-cpuidle", -1, NULL, 0);
377 platform_driver_unregister(&psci_cpuidle_driver);
378 return PTR_ERR(pdev);
383 device_initcall(psci_idle_init);