summaryrefslogtreecommitdiffstats
path: root/drivers/cpuidle/cpuidle-psci.c
blob: b51b5df084500183667dae6adb9a12dc32b76dcf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
// SPDX-License-Identifier: GPL-2.0-only
/*
 * PSCI CPU idle driver.
 *
 * Copyright (C) 2019 ARM Ltd.
 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
 */

#define pr_fmt(fmt) "CPUidle PSCI: " fmt

#include <linux/cpuhotplug.h>
#include <linux/cpu_cooling.h>
#include <linux/cpuidle.h>
#include <linux/cpumask.h>
#include <linux/cpu_pm.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/psci.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <asm/cpuidle.h>

#include "cpuidle-psci.h"
#include "dt_idle_states.h"

struct psci_cpuidle_data {
	u32 *psci_states;
	struct device *dev;
};

static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data);
static DEFINE_PER_CPU(u32, domain_state);
static bool psci_cpuidle_use_cpuhp;

void psci_set_domain_state(u32 state)
{
	__this_cpu_write(domain_state, state);
}

static inline u32 psci_get_domain_state(void)
{
	return __this_cpu_read(domain_state);
}

static inline int psci_enter_state(int idx, u32 state)
{
	return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, idx, state);
}

static int __psci_enter_domain_idle_state(struct cpuidle_device *dev,
					  struct cpuidle_driver *drv, int idx,
					  bool s2idle)
{
	struct psci_cpuidle_data *data = this_cpu_ptr(&psci_cpuidle_data);
	u32 *states = data->psci_states;
	struct device *pd_dev = data->dev;
	u32 state;
	int ret;

	ret = cpu_pm_enter();
	if (ret)
		return -1;

	/* Do runtime PM to manage a hierarchical CPU toplogy. */
	rcu_irq_enter_irqson();
	if (s2idle)
		dev_pm_genpd_suspend(pd_dev);
	else
		pm_runtime_put_sync_suspend(pd_dev);
	rcu_irq_exit_irqson();

	state = psci_get_domain_state();
	if (!state)
		state = states[idx];

	ret = psci_cpu_suspend_enter(state) ? -1 : idx;

	rcu_irq_enter_irqson();
	if (s2idle)
		dev_pm_genpd_resume(pd_dev);
	else
		pm_runtime_get_sync(pd_dev);
	rcu_irq_exit_irqson();

	cpu_pm_exit();

	/* Clear the domain state to start fresh when back from idle. */
	psci_set_domain_state(0);
	return ret;
}

static int psci_enter_domain_idle_state(struct cpuidle_device *dev,
					struct cpuidle_driver *drv, int idx)
{
	return __psci_enter_domain_idle_state(dev, drv, idx, false);
}

static int psci_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
					       struct cpuidle_driver *drv,
					       int idx)
{
	return __psci_enter_domain_idle_state(dev, drv, idx, true);
}

static int psci_idle_cpuhp_up(unsigned int cpu)
{
	struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);

	if (pd_dev)
		pm_runtime_get_sync(pd_dev);

	return 0;
}

static int psci_idle_cpuhp_down(unsigned int cpu)
{
	struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);

	if (pd_dev) {
		pm_runtime_put_sync(pd_dev);
		/* Clear domain state to start fresh at next online. */
		psci_set_domain_state(0);
	}

	return 0;
}

static void psci_idle_init_cpuhp(void)
{
	int err;

	if (!psci_cpuidle_use_cpuhp)
		return;

	err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
					"cpuidle/psci:online",
					psci_idle_cpuhp_up,
					psci_idle_cpuhp_down);
	if (err)
		pr_warn("Failed %d while setup cpuhp state\n", err);
}

static int psci_enter_idle_state(struct cpuidle_device *dev,
				struct cpuidle_driver *drv, int idx)
{
	u32 *state = __this_cpu_read(psci_cpuidle_data.psci_states);

	return psci_enter_state(idx, state[idx]);
}

static const struct of_device_id psci_idle_state_match[] = {
	{ .compatible = "arm,idle-state",
	  .data = psci_enter_idle_state },
	{ },
};

int psci_dt_parse_state_node(struct device_node *np, u32 *state)
{
	int err = of_property_read_u32(np, "arm,psci-suspend-param", state);

	if (err) {
		pr_warn("%pOF missing arm,psci-suspend-param property\n", np);
		return err;
	}

	if (!psci_power_state_is_valid(*state)) {
		pr_warn("Invalid PSCI power state %#x\n", *state);
		return -EINVAL;
	}

	return 0;
}

static int psci_dt_cpu_init_topology(struct cpuidle_driver *drv,
				     struct psci_cpuidle_data *data,
				     unsigned int state_count, int cpu)
{
	/* Currently limit the hierarchical topology to be used in OSI mode. */
	if (!psci_has_osi_support())
		return 0;

	data->dev = psci_dt_attach_cpu(cpu);
	if (IS_ERR_OR_NULL(data->dev))
		return PTR_ERR_OR_ZERO(data->dev);

	/*
	 * Using the deepest state for the CPU to trigger a potential selection
	 * of a shared state for the domain, assumes the domain states are all
	 * deeper states.
	 */
	drv->states[state_count - 1].enter = psci_enter_domain_idle_state;
	drv->states[state_count - 1].enter_s2idle = psci_enter_s2idle_domain_idle_state;
	psci_cpuidle_use_cpuhp = true;

	return 0;
}

static int psci_dt_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv,
				 struct device_node *cpu_node,
				 unsigned int state_count, int cpu)
{
	int i, ret = 0;
	u32 *psci_states;
	struct device_node *state_node;
	struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu);

	state_count++; /* Add WFI state too */
	psci_states = devm_kcalloc(dev, state_count, sizeof(*psci_states),
				   GFP_KERNEL);
	if (!psci_states)
		return -ENOMEM;

	for (i = 1; i < state_count; i++) {
		state_node = of_get_cpu_state_node(cpu_node, i - 1);
		if (!state_node)
			break;

		ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
		of_node_put(state_node);

		if (ret)
			return ret;

		pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
	}

	if (i != state_count)
		return -ENODEV;

	/* Initialize optional data, used for the hierarchical topology. */
	ret = psci_dt_cpu_init_topology(drv, data, state_count, cpu);
	if (ret < 0)
		return ret;

	/* Idle states parsed correctly, store them in the per-cpu struct. */
	data->psci_states = psci_states;
	return 0;
}

static int psci_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv,
			      unsigned int cpu, unsigned int state_count)
{
	struct device_node *cpu_node;
	int ret;

	/*
	 * If the PSCI cpu_suspend function hook has not been initialized
	 * idle states must not be enabled, so bail out
	 */
	if (!psci_ops.cpu_suspend)
		return -EOPNOTSUPP;

	cpu_node = of_cpu_device_node_get(cpu);
	if (!cpu_node)
		return -ENODEV;

	ret = psci_dt_cpu_init_idle(dev, drv, cpu_node, state_count, cpu);

	of_node_put(cpu_node);

	return ret;
}

static void psci_cpu_deinit_idle(int cpu)
{
	struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu);

	psci_dt_detach_cpu(data->dev);
	psci_cpuidle_use_cpuhp = false;
}

static int psci_idle_init_cpu(struct device *dev, int cpu)
{
	struct cpuidle_driver *drv;
	struct device_node *cpu_node;
	const char *enable_method;
	int ret = 0;

	cpu_node = of_cpu_device_node_get(cpu);
	if (!cpu_node)
		return -ENODEV;

	/*
	 * Check whether the enable-method for the cpu is PSCI, fail
	 * if it is not.
	 */
	enable_method = of_get_property(cpu_node, "enable-method", NULL);
	if (!enable_method || (strcmp(enable_method, "psci")))
		ret = -ENODEV;

	of_node_put(cpu_node);
	if (ret)
		return ret;

	drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
	if (!drv)
		return -ENOMEM;

	drv->name = "psci_idle";
	drv->owner = THIS_MODULE;
	drv->cpumask = (struct cpumask *)cpumask_of(cpu);

	/*
	 * PSCI idle states relies on architectural WFI to be represented as
	 * state index 0.
	 */
	drv->states[0].enter = psci_enter_idle_state;
	drv->states[0].exit_latency = 1;
	drv->states[0].target_residency = 1;
	drv->states[0].power_usage = UINT_MAX;
	strcpy(drv->states[0].name, "WFI");
	strcpy(drv->states[0].desc, "ARM WFI");

	/*
	 * If no DT idle states are detected (ret == 0) let the driver
	 * initialization fail accordingly since there is no reason to
	 * initialize the idle driver if only wfi is supported, the
	 * default archictectural back-end already executes wfi
	 * on idle entry.
	 */
	ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
	if (ret <= 0)
		return ret ? : -ENODEV;

	/*
	 * Initialize PSCI idle states.
	 */
	ret = psci_cpu_init_idle(dev, drv, cpu, ret);
	if (ret) {
		pr_err("CPU %d failed to PSCI idle\n", cpu);
		return ret;
	}

	ret = cpuidle_register(drv, NULL);
	if (ret)
		goto deinit;

	cpuidle_cooling_register(drv);

	return 0;
deinit:
	psci_cpu_deinit_idle(cpu);
	return ret;
}

/*
 * psci_idle_probe - Initializes PSCI cpuidle driver
 *
 * Initializes PSCI cpuidle driver for all CPUs, if any CPU fails
 * to register cpuidle driver then rollback to cancel all CPUs
 * registration.
 */
static int psci_cpuidle_probe(struct platform_device *pdev)
{
	int cpu, ret;
	struct cpuidle_driver *drv;
	struct cpuidle_device *dev;

	for_each_possible_cpu(cpu) {
		ret = psci_idle_init_cpu(&pdev->dev, cpu);
		if (ret)
			goto out_fail;
	}

	psci_idle_init_cpuhp();
	return 0;

out_fail:
	while (--cpu >= 0) {
		dev = per_cpu(cpuidle_devices, cpu);
		drv = cpuidle_get_cpu_driver(dev);
		cpuidle_unregister(drv);
		psci_cpu_deinit_idle(cpu);
	}

	return ret;
}

static struct platform_driver psci_cpuidle_driver = {
	.probe = psci_cpuidle_probe,
	.driver = {
		.name = "psci-cpuidle",
	},
};

static int __init psci_idle_init(void)
{
	struct platform_device *pdev;
	int ret;

	ret = platform_driver_register(&psci_cpuidle_driver);
	if (ret)
		return ret;

	pdev = platform_device_register_simple("psci-cpuidle", -1, NULL, 0);
	if (IS_ERR(pdev)) {
		platform_driver_unregister(&psci_cpuidle_driver);
		return PTR_ERR(pdev);
	}

	return 0;
}
device_initcall(psci_idle_init);