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81d549e0 LP |
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 | ||
9c6ceecb | 11 | #include <linux/cpuhotplug.h> |
fc7a3d9e | 12 | #include <linux/cpu_cooling.h> |
81d549e0 LP |
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> | |
166bf835 | 20 | #include <linux/platform_device.h> |
81d549e0 | 21 | #include <linux/psci.h> |
ce85aef5 | 22 | #include <linux/pm_runtime.h> |
81d549e0 | 23 | #include <linux/slab.h> |
166bf835 | 24 | #include <linux/string.h> |
81d549e0 LP |
25 | |
26 | #include <asm/cpuidle.h> | |
27 | ||
8554951a | 28 | #include "cpuidle-psci.h" |
81d549e0 LP |
29 | #include "dt_idle_states.h" |
30 | ||
8554951a UH |
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); | |
a0cf3194 | 37 | static DEFINE_PER_CPU(u32, domain_state); |
166bf835 | 38 | static bool psci_cpuidle_use_cpuhp; |
a0cf3194 | 39 | |
a65a397f | 40 | void psci_set_domain_state(u32 state) |
a0cf3194 UH |
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; | |
ce85aef5 UH |
60 | struct device *pd_dev = data->dev; |
61 | u32 state; | |
a0cf3194 UH |
62 | int ret; |
63 | ||
8b7ce5e4 UH |
64 | ret = cpu_pm_enter(); |
65 | if (ret) | |
66 | return -1; | |
67 | ||
ce85aef5 | 68 | /* Do runtime PM to manage a hierarchical CPU toplogy. */ |
36050d89 | 69 | RCU_NONIDLE(pm_runtime_put_sync_suspend(pd_dev)); |
ce85aef5 UH |
70 | |
71 | state = psci_get_domain_state(); | |
a0cf3194 UH |
72 | if (!state) |
73 | state = states[idx]; | |
74 | ||
8b7ce5e4 | 75 | ret = psci_cpu_suspend_enter(state) ? -1 : idx; |
a0cf3194 | 76 | |
36050d89 | 77 | RCU_NONIDLE(pm_runtime_get_sync(pd_dev)); |
ce85aef5 | 78 | |
8b7ce5e4 UH |
79 | cpu_pm_exit(); |
80 | ||
a0cf3194 UH |
81 | /* Clear the domain state to start fresh when back from idle. */ |
82 | psci_set_domain_state(0); | |
83 | return ret; | |
84 | } | |
9ffeb6d0 | 85 | |
9c6ceecb UH |
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 | ||
166bf835 | 109 | static void psci_idle_init_cpuhp(void) |
9c6ceecb UH |
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 | ||
81d549e0 LP |
124 | static int psci_enter_idle_state(struct cpuidle_device *dev, |
125 | struct cpuidle_driver *drv, int idx) | |
126 | { | |
8554951a | 127 | u32 *state = __this_cpu_read(psci_cpuidle_data.psci_states); |
9ffeb6d0 | 128 | |
a0cf3194 | 129 | return psci_enter_state(idx, state[idx]); |
81d549e0 LP |
130 | } |
131 | ||
166bf835 | 132 | static const struct of_device_id psci_idle_state_match[] = { |
81d549e0 LP |
133 | { .compatible = "arm,idle-state", |
134 | .data = psci_enter_idle_state }, | |
135 | { }, | |
136 | }; | |
137 | ||
166bf835 | 138 | int psci_dt_parse_state_node(struct device_node *np, u32 *state) |
9ffeb6d0 LP |
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 | ||
166bf835 UH |
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) | |
7fbee48e UH |
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 | ||
166bf835 UH |
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) | |
9ffeb6d0 | 181 | { |
1595e4b0 | 182 | int i, ret = 0; |
9ffeb6d0 LP |
183 | u32 *psci_states; |
184 | struct device_node *state_node; | |
8554951a | 185 | struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu); |
9ffeb6d0 | 186 | |
1595e4b0 | 187 | state_count++; /* Add WFI state too */ |
166bf835 UH |
188 | psci_states = devm_kcalloc(dev, state_count, sizeof(*psci_states), |
189 | GFP_KERNEL); | |
9ffeb6d0 LP |
190 | if (!psci_states) |
191 | return -ENOMEM; | |
192 | ||
1595e4b0 | 193 | for (i = 1; i < state_count; i++) { |
f08cfbfa | 194 | state_node = of_get_cpu_state_node(cpu_node, i - 1); |
1595e4b0 UH |
195 | if (!state_node) |
196 | break; | |
197 | ||
9ffeb6d0 LP |
198 | ret = psci_dt_parse_state_node(state_node, &psci_states[i]); |
199 | of_node_put(state_node); | |
200 | ||
201 | if (ret) | |
166bf835 | 202 | return ret; |
9ffeb6d0 LP |
203 | |
204 | pr_debug("psci-power-state %#x index %d\n", psci_states[i], i); | |
205 | } | |
206 | ||
166bf835 UH |
207 | if (i != state_count) |
208 | return -ENODEV; | |
1595e4b0 | 209 | |
7fbee48e UH |
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) | |
166bf835 | 213 | return ret; |
8554951a UH |
214 | |
215 | /* Idle states parsed correctly, store them in the per-cpu struct. */ | |
216 | data->psci_states = psci_states; | |
9ffeb6d0 | 217 | return 0; |
9ffeb6d0 LP |
218 | } |
219 | ||
166bf835 UH |
220 | static int psci_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv, |
221 | unsigned int cpu, unsigned int state_count) | |
9ffeb6d0 LP |
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 | ||
166bf835 | 237 | ret = psci_dt_cpu_init_idle(dev, drv, cpu_node, state_count, cpu); |
9ffeb6d0 LP |
238 | |
239 | of_node_put(cpu_node); | |
240 | ||
241 | return ret; | |
242 | } | |
243 | ||
166bf835 UH |
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) | |
81d549e0 LP |
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 | ||
166bf835 | 275 | drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL); |
81d549e0 LP |
276 | if (!drv) |
277 | return -ENOMEM; | |
278 | ||
166bf835 UH |
279 | drv->name = "psci_idle"; |
280 | drv->owner = THIS_MODULE; | |
81d549e0 LP |
281 | drv->cpumask = (struct cpumask *)cpumask_of(cpu); |
282 | ||
283 | /* | |
166bf835 UH |
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 | /* | |
81d549e0 LP |
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); | |
166bf835 UH |
302 | if (ret <= 0) |
303 | return ret ? : -ENODEV; | |
81d549e0 LP |
304 | |
305 | /* | |
306 | * Initialize PSCI idle states. | |
307 | */ | |
166bf835 | 308 | ret = psci_cpu_init_idle(dev, drv, cpu, ret); |
81d549e0 LP |
309 | if (ret) { |
310 | pr_err("CPU %d failed to PSCI idle\n", cpu); | |
166bf835 | 311 | return ret; |
81d549e0 LP |
312 | } |
313 | ||
314 | ret = cpuidle_register(drv, NULL); | |
315 | if (ret) | |
166bf835 | 316 | goto deinit; |
81d549e0 | 317 | |
fc7a3d9e DL |
318 | cpuidle_cooling_register(drv); |
319 | ||
81d549e0 | 320 | return 0; |
166bf835 UH |
321 | deinit: |
322 | psci_cpu_deinit_idle(cpu); | |
81d549e0 LP |
323 | return ret; |
324 | } | |
325 | ||
326 | /* | |
166bf835 | 327 | * psci_idle_probe - Initializes PSCI cpuidle driver |
81d549e0 LP |
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 | */ | |
166bf835 | 333 | static int psci_cpuidle_probe(struct platform_device *pdev) |
81d549e0 LP |
334 | { |
335 | int cpu, ret; | |
336 | struct cpuidle_driver *drv; | |
337 | struct cpuidle_device *dev; | |
338 | ||
339 | for_each_possible_cpu(cpu) { | |
166bf835 | 340 | ret = psci_idle_init_cpu(&pdev->dev, cpu); |
81d549e0 LP |
341 | if (ret) |
342 | goto out_fail; | |
343 | } | |
344 | ||
9c6ceecb | 345 | psci_idle_init_cpuhp(); |
81d549e0 LP |
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); | |
166bf835 | 353 | psci_cpu_deinit_idle(cpu); |
81d549e0 LP |
354 | } |
355 | ||
356 | return ret; | |
357 | } | |
166bf835 UH |
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 | } | |
81d549e0 | 383 | device_initcall(psci_idle_init); |