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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/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>
18#include <linux/of.h>
19#include <linux/platform_device.h>
20#include <linux/psci.h>
21#include <linux/pm_domain.h>
22#include <linux/pm_runtime.h>
23#include <linux/slab.h>
24#include <linux/string.h>
25#include <linux/syscore_ops.h>
26
27#include <asm/cpuidle.h>
28
29#include "cpuidle-psci.h"
30#include "dt_idle_states.h"
31
32struct psci_cpuidle_data {
33 u32 *psci_states;
34 struct device *dev;
35};
36
37static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data);
38static DEFINE_PER_CPU(u32, domain_state);
39static bool psci_cpuidle_use_cpuhp;
40
41void psci_set_domain_state(u32 state)
42{
43 __this_cpu_write(domain_state, state);
44}
45
46static inline u32 psci_get_domain_state(void)
47{
48 return __this_cpu_read(domain_state);
49}
50
51static __cpuidle int __psci_enter_domain_idle_state(struct cpuidle_device *dev,
52 struct cpuidle_driver *drv, int idx,
53 bool s2idle)
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 ret = cpu_pm_enter();
62 if (ret)
63 return -1;
64
65 /* Do runtime PM to manage a hierarchical CPU toplogy. */
66 if (s2idle)
67 dev_pm_genpd_suspend(pd_dev);
68 else
69 pm_runtime_put_sync_suspend(pd_dev);
70
71 state = psci_get_domain_state();
72 if (!state)
73 state = states[idx];
74
75 ret = psci_cpu_suspend_enter(state) ? -1 : idx;
76
77 if (s2idle)
78 dev_pm_genpd_resume(pd_dev);
79 else
80 pm_runtime_get_sync(pd_dev);
81
82 cpu_pm_exit();
83
84 /* Clear the domain state to start fresh when back from idle. */
85 psci_set_domain_state(0);
86 return ret;
87}
88
89static int psci_enter_domain_idle_state(struct cpuidle_device *dev,
90 struct cpuidle_driver *drv, int idx)
91{
92 return __psci_enter_domain_idle_state(dev, drv, idx, false);
93}
94
95static int psci_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
96 struct cpuidle_driver *drv,
97 int idx)
98{
99 return __psci_enter_domain_idle_state(dev, drv, idx, true);
100}
101
102static int psci_idle_cpuhp_up(unsigned int cpu)
103{
104 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);
105
106 if (pd_dev)
107 pm_runtime_get_sync(pd_dev);
108
109 return 0;
110}
111
112static int psci_idle_cpuhp_down(unsigned int cpu)
113{
114 struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);
115
116 if (pd_dev) {
117 pm_runtime_put_sync(pd_dev);
118 /* Clear domain state to start fresh at next online. */
119 psci_set_domain_state(0);
120 }
121
122 return 0;
123}
124
125static void psci_idle_syscore_switch(bool suspend)
126{
127 bool cleared = false;
128 struct device *dev;
129 int cpu;
130
131 for_each_possible_cpu(cpu) {
132 dev = per_cpu_ptr(&psci_cpuidle_data, cpu)->dev;
133
134 if (dev && suspend) {
135 dev_pm_genpd_suspend(dev);
136 } else if (dev) {
137 dev_pm_genpd_resume(dev);
138
139 /* Account for userspace having offlined a CPU. */
140 if (pm_runtime_status_suspended(dev))
141 pm_runtime_set_active(dev);
142
143 /* Clear domain state to re-start fresh. */
144 if (!cleared) {
145 psci_set_domain_state(0);
146 cleared = true;
147 }
148 }
149 }
150}
151
152static int psci_idle_syscore_suspend(void)
153{
154 psci_idle_syscore_switch(true);
155 return 0;
156}
157
158static void psci_idle_syscore_resume(void)
159{
160 psci_idle_syscore_switch(false);
161}
162
163static struct syscore_ops psci_idle_syscore_ops = {
164 .suspend = psci_idle_syscore_suspend,
165 .resume = psci_idle_syscore_resume,
166};
167
168static void psci_idle_init_cpuhp(void)
169{
170 int err;
171
172 if (!psci_cpuidle_use_cpuhp)
173 return;
174
175 register_syscore_ops(&psci_idle_syscore_ops);
176
177 err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
178 "cpuidle/psci:online",
179 psci_idle_cpuhp_up,
180 psci_idle_cpuhp_down);
181 if (err)
182 pr_warn("Failed %d while setup cpuhp state\n", err);
183}
184
185static __cpuidle int psci_enter_idle_state(struct cpuidle_device *dev,
186 struct cpuidle_driver *drv, int idx)
187{
188 u32 *state = __this_cpu_read(psci_cpuidle_data.psci_states);
189
190 return CPU_PM_CPU_IDLE_ENTER_PARAM_RCU(psci_cpu_suspend_enter, idx, state[idx]);
191}
192
193static const struct of_device_id psci_idle_state_match[] = {
194 { .compatible = "arm,idle-state",
195 .data = psci_enter_idle_state },
196 { },
197};
198
199int psci_dt_parse_state_node(struct device_node *np, u32 *state)
200{
201 int err = of_property_read_u32(np, "arm,psci-suspend-param", state);
202
203 if (err) {
204 pr_warn("%pOF missing arm,psci-suspend-param property\n", np);
205 return err;
206 }
207
208 if (!psci_power_state_is_valid(*state)) {
209 pr_warn("Invalid PSCI power state %#x\n", *state);
210 return -EINVAL;
211 }
212
213 return 0;
214}
215
216static int psci_dt_cpu_init_topology(struct cpuidle_driver *drv,
217 struct psci_cpuidle_data *data,
218 unsigned int state_count, int cpu)
219{
220 /* Currently limit the hierarchical topology to be used in OSI mode. */
221 if (!psci_has_osi_support())
222 return 0;
223
224 if (IS_ENABLED(CONFIG_PREEMPT_RT))
225 return 0;
226
227 data->dev = psci_dt_attach_cpu(cpu);
228 if (IS_ERR_OR_NULL(data->dev))
229 return PTR_ERR_OR_ZERO(data->dev);
230
231 /*
232 * Using the deepest state for the CPU to trigger a potential selection
233 * of a shared state for the domain, assumes the domain states are all
234 * deeper states.
235 */
236 drv->states[state_count - 1].flags |= CPUIDLE_FLAG_RCU_IDLE;
237 drv->states[state_count - 1].enter = psci_enter_domain_idle_state;
238 drv->states[state_count - 1].enter_s2idle = psci_enter_s2idle_domain_idle_state;
239 psci_cpuidle_use_cpuhp = true;
240
241 return 0;
242}
243
244static int psci_dt_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv,
245 struct device_node *cpu_node,
246 unsigned int state_count, int cpu)
247{
248 int i, ret = 0;
249 u32 *psci_states;
250 struct device_node *state_node;
251 struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu);
252
253 state_count++; /* Add WFI state too */
254 psci_states = devm_kcalloc(dev, state_count, sizeof(*psci_states),
255 GFP_KERNEL);
256 if (!psci_states)
257 return -ENOMEM;
258
259 for (i = 1; i < state_count; i++) {
260 state_node = of_get_cpu_state_node(cpu_node, i - 1);
261 if (!state_node)
262 break;
263
264 ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
265 of_node_put(state_node);
266
267 if (ret)
268 return ret;
269
270 pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
271 }
272
273 if (i != state_count)
274 return -ENODEV;
275
276 /* Initialize optional data, used for the hierarchical topology. */
277 ret = psci_dt_cpu_init_topology(drv, data, state_count, cpu);
278 if (ret < 0)
279 return ret;
280
281 /* Idle states parsed correctly, store them in the per-cpu struct. */
282 data->psci_states = psci_states;
283 return 0;
284}
285
286static int psci_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv,
287 unsigned int cpu, unsigned int state_count)
288{
289 struct device_node *cpu_node;
290 int ret;
291
292 /*
293 * If the PSCI cpu_suspend function hook has not been initialized
294 * idle states must not be enabled, so bail out
295 */
296 if (!psci_ops.cpu_suspend)
297 return -EOPNOTSUPP;
298
299 cpu_node = of_cpu_device_node_get(cpu);
300 if (!cpu_node)
301 return -ENODEV;
302
303 ret = psci_dt_cpu_init_idle(dev, drv, cpu_node, state_count, cpu);
304
305 of_node_put(cpu_node);
306
307 return ret;
308}
309
310static void psci_cpu_deinit_idle(int cpu)
311{
312 struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu);
313
314 psci_dt_detach_cpu(data->dev);
315 psci_cpuidle_use_cpuhp = false;
316}
317
318static int psci_idle_init_cpu(struct device *dev, int cpu)
319{
320 struct cpuidle_driver *drv;
321 struct device_node *cpu_node;
322 const char *enable_method;
323 int ret = 0;
324
325 cpu_node = of_cpu_device_node_get(cpu);
326 if (!cpu_node)
327 return -ENODEV;
328
329 /*
330 * Check whether the enable-method for the cpu is PSCI, fail
331 * if it is not.
332 */
333 enable_method = of_get_property(cpu_node, "enable-method", NULL);
334 if (!enable_method || (strcmp(enable_method, "psci")))
335 ret = -ENODEV;
336
337 of_node_put(cpu_node);
338 if (ret)
339 return ret;
340
341 drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
342 if (!drv)
343 return -ENOMEM;
344
345 drv->name = "psci_idle";
346 drv->owner = THIS_MODULE;
347 drv->cpumask = (struct cpumask *)cpumask_of(cpu);
348
349 /*
350 * PSCI idle states relies on architectural WFI to be represented as
351 * state index 0.
352 */
353 drv->states[0].enter = psci_enter_idle_state;
354 drv->states[0].exit_latency = 1;
355 drv->states[0].target_residency = 1;
356 drv->states[0].power_usage = UINT_MAX;
357 strcpy(drv->states[0].name, "WFI");
358 strcpy(drv->states[0].desc, "ARM WFI");
359
360 /*
361 * If no DT idle states are detected (ret == 0) let the driver
362 * initialization fail accordingly since there is no reason to
363 * initialize the idle driver if only wfi is supported, the
364 * default archictectural back-end already executes wfi
365 * on idle entry.
366 */
367 ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
368 if (ret <= 0)
369 return ret ? : -ENODEV;
370
371 /*
372 * Initialize PSCI idle states.
373 */
374 ret = psci_cpu_init_idle(dev, drv, cpu, ret);
375 if (ret) {
376 pr_err("CPU %d failed to PSCI idle\n", cpu);
377 return ret;
378 }
379
380 ret = cpuidle_register(drv, NULL);
381 if (ret)
382 goto deinit;
383
384 cpuidle_cooling_register(drv);
385
386 return 0;
387deinit:
388 psci_cpu_deinit_idle(cpu);
389 return ret;
390}
391
392/*
393 * psci_idle_probe - Initializes PSCI cpuidle driver
394 *
395 * Initializes PSCI cpuidle driver for all CPUs, if any CPU fails
396 * to register cpuidle driver then rollback to cancel all CPUs
397 * registration.
398 */
399static int psci_cpuidle_probe(struct platform_device *pdev)
400{
401 int cpu, ret;
402 struct cpuidle_driver *drv;
403 struct cpuidle_device *dev;
404
405 for_each_possible_cpu(cpu) {
406 ret = psci_idle_init_cpu(&pdev->dev, cpu);
407 if (ret)
408 goto out_fail;
409 }
410
411 psci_idle_init_cpuhp();
412 return 0;
413
414out_fail:
415 while (--cpu >= 0) {
416 dev = per_cpu(cpuidle_devices, cpu);
417 drv = cpuidle_get_cpu_driver(dev);
418 cpuidle_unregister(drv);
419 psci_cpu_deinit_idle(cpu);
420 }
421
422 return ret;
423}
424
425static struct platform_driver psci_cpuidle_driver = {
426 .probe = psci_cpuidle_probe,
427 .driver = {
428 .name = "psci-cpuidle",
429 },
430};
431
432static int __init psci_idle_init(void)
433{
434 struct platform_device *pdev;
435 int ret;
436
437 ret = platform_driver_register(&psci_cpuidle_driver);
438 if (ret)
439 return ret;
440
441 pdev = platform_device_register_simple("psci-cpuidle", -1, NULL, 0);
442 if (IS_ERR(pdev)) {
443 platform_driver_unregister(&psci_cpuidle_driver);
444 return PTR_ERR(pdev);
445 }
446
447 return 0;
448}
449device_initcall(psci_idle_init);
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/cpuidle.h>
12#include <linux/cpumask.h>
13#include <linux/cpu_pm.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/of_device.h>
18#include <linux/psci.h>
19#include <linux/slab.h>
20
21#include <asm/cpuidle.h>
22
23#include "dt_idle_states.h"
24
25static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
26
27static int psci_enter_idle_state(struct cpuidle_device *dev,
28 struct cpuidle_driver *drv, int idx)
29{
30 u32 *state = __this_cpu_read(psci_power_state);
31
32 return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter,
33 idx, state[idx - 1]);
34}
35
36static struct cpuidle_driver psci_idle_driver __initdata = {
37 .name = "psci_idle",
38 .owner = THIS_MODULE,
39 /*
40 * PSCI idle states relies on architectural WFI to
41 * be represented as state index 0.
42 */
43 .states[0] = {
44 .enter = psci_enter_idle_state,
45 .exit_latency = 1,
46 .target_residency = 1,
47 .power_usage = UINT_MAX,
48 .name = "WFI",
49 .desc = "ARM WFI",
50 }
51};
52
53static const struct of_device_id psci_idle_state_match[] __initconst = {
54 { .compatible = "arm,idle-state",
55 .data = psci_enter_idle_state },
56 { },
57};
58
59static int __init psci_dt_parse_state_node(struct device_node *np, u32 *state)
60{
61 int err = of_property_read_u32(np, "arm,psci-suspend-param", state);
62
63 if (err) {
64 pr_warn("%pOF missing arm,psci-suspend-param property\n", np);
65 return err;
66 }
67
68 if (!psci_power_state_is_valid(*state)) {
69 pr_warn("Invalid PSCI power state %#x\n", *state);
70 return -EINVAL;
71 }
72
73 return 0;
74}
75
76static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
77{
78 int i, ret = 0, count = 0;
79 u32 *psci_states;
80 struct device_node *state_node;
81
82 /* Count idle states */
83 while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
84 count))) {
85 count++;
86 of_node_put(state_node);
87 }
88
89 if (!count)
90 return -ENODEV;
91
92 psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
93 if (!psci_states)
94 return -ENOMEM;
95
96 for (i = 0; i < count; i++) {
97 state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
98 ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
99 of_node_put(state_node);
100
101 if (ret)
102 goto free_mem;
103
104 pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
105 }
106
107 /* Idle states parsed correctly, initialize per-cpu pointer */
108 per_cpu(psci_power_state, cpu) = psci_states;
109 return 0;
110
111free_mem:
112 kfree(psci_states);
113 return ret;
114}
115
116static __init int psci_cpu_init_idle(unsigned int cpu)
117{
118 struct device_node *cpu_node;
119 int ret;
120
121 /*
122 * If the PSCI cpu_suspend function hook has not been initialized
123 * idle states must not be enabled, so bail out
124 */
125 if (!psci_ops.cpu_suspend)
126 return -EOPNOTSUPP;
127
128 cpu_node = of_cpu_device_node_get(cpu);
129 if (!cpu_node)
130 return -ENODEV;
131
132 ret = psci_dt_cpu_init_idle(cpu_node, cpu);
133
134 of_node_put(cpu_node);
135
136 return ret;
137}
138
139static int __init psci_idle_init_cpu(int cpu)
140{
141 struct cpuidle_driver *drv;
142 struct device_node *cpu_node;
143 const char *enable_method;
144 int ret = 0;
145
146 cpu_node = of_cpu_device_node_get(cpu);
147 if (!cpu_node)
148 return -ENODEV;
149
150 /*
151 * Check whether the enable-method for the cpu is PSCI, fail
152 * if it is not.
153 */
154 enable_method = of_get_property(cpu_node, "enable-method", NULL);
155 if (!enable_method || (strcmp(enable_method, "psci")))
156 ret = -ENODEV;
157
158 of_node_put(cpu_node);
159 if (ret)
160 return ret;
161
162 drv = kmemdup(&psci_idle_driver, sizeof(*drv), GFP_KERNEL);
163 if (!drv)
164 return -ENOMEM;
165
166 drv->cpumask = (struct cpumask *)cpumask_of(cpu);
167
168 /*
169 * Initialize idle states data, starting at index 1, since
170 * by default idle state 0 is the quiescent state reached
171 * by the cpu by executing the wfi instruction.
172 *
173 * If no DT idle states are detected (ret == 0) let the driver
174 * initialization fail accordingly since there is no reason to
175 * initialize the idle driver if only wfi is supported, the
176 * default archictectural back-end already executes wfi
177 * on idle entry.
178 */
179 ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
180 if (ret <= 0) {
181 ret = ret ? : -ENODEV;
182 goto out_kfree_drv;
183 }
184
185 /*
186 * Initialize PSCI idle states.
187 */
188 ret = psci_cpu_init_idle(cpu);
189 if (ret) {
190 pr_err("CPU %d failed to PSCI idle\n", cpu);
191 goto out_kfree_drv;
192 }
193
194 ret = cpuidle_register(drv, NULL);
195 if (ret)
196 goto out_kfree_drv;
197
198 return 0;
199
200out_kfree_drv:
201 kfree(drv);
202 return ret;
203}
204
205/*
206 * psci_idle_init - Initializes PSCI cpuidle driver
207 *
208 * Initializes PSCI cpuidle driver for all CPUs, if any CPU fails
209 * to register cpuidle driver then rollback to cancel all CPUs
210 * registration.
211 */
212static int __init psci_idle_init(void)
213{
214 int cpu, ret;
215 struct cpuidle_driver *drv;
216 struct cpuidle_device *dev;
217
218 for_each_possible_cpu(cpu) {
219 ret = psci_idle_init_cpu(cpu);
220 if (ret)
221 goto out_fail;
222 }
223
224 return 0;
225
226out_fail:
227 while (--cpu >= 0) {
228 dev = per_cpu(cpuidle_devices, cpu);
229 drv = cpuidle_get_cpu_driver(dev);
230 cpuidle_unregister(drv);
231 kfree(drv);
232 }
233
234 return ret;
235}
236device_initcall(psci_idle_init);