aboutsummaryrefslogtreecommitdiff
path: root/drivers/cpuidle/cpuidle-riscv-sbi.c
blob: 05fe2902df9a7858bf6ba18d8b71c97c0a112fb9 (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
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
// SPDX-License-Identifier: GPL-2.0-only
/*
 * RISC-V SBI CPU idle driver.
 *
 * Copyright (c) 2021 Western Digital Corporation or its affiliates.
 * Copyright (c) 2022 Ventana Micro Systems Inc.
 */

#define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt

#include <linux/cpuidle.h>
#include <linux/cpumask.h>
#include <linux/cpu_pm.h>
#include <linux/cpu_cooling.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <asm/cpuidle.h>
#include <asm/sbi.h>
#include <asm/smp.h>
#include <asm/suspend.h>

#include "dt_idle_states.h"
#include "dt_idle_genpd.h"

struct sbi_cpuidle_data {
	u32 *states;
	struct device *dev;
};

struct sbi_domain_state {
	bool available;
	u32 state;
};

static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
static bool sbi_cpuidle_use_osi;
static bool sbi_cpuidle_use_cpuhp;
static bool sbi_cpuidle_pd_allow_domain_state;

static inline void sbi_set_domain_state(u32 state)
{
	struct sbi_domain_state *data = this_cpu_ptr(&domain_state);

	data->available = true;
	data->state = state;
}

static inline u32 sbi_get_domain_state(void)
{
	struct sbi_domain_state *data = this_cpu_ptr(&domain_state);

	return data->state;
}

static inline void sbi_clear_domain_state(void)
{
	struct sbi_domain_state *data = this_cpu_ptr(&domain_state);

	data->available = false;
}

static inline bool sbi_is_domain_state_available(void)
{
	struct sbi_domain_state *data = this_cpu_ptr(&domain_state);

	return data->available;
}

static int sbi_suspend_finisher(unsigned long suspend_type,
				unsigned long resume_addr,
				unsigned long opaque)
{
	struct sbiret ret;

	ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
			suspend_type, resume_addr, opaque, 0, 0, 0);

	return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
}

static int sbi_suspend(u32 state)
{
	if (state & SBI_HSM_SUSP_NON_RET_BIT)
		return cpu_suspend(state, sbi_suspend_finisher);
	else
		return sbi_suspend_finisher(state, 0, 0);
}

static int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
				   struct cpuidle_driver *drv, int idx)
{
	u32 *states = __this_cpu_read(sbi_cpuidle_data.states);
	u32 state = states[idx];

	if (state & SBI_HSM_SUSP_NON_RET_BIT)
		return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, state);
	else
		return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(sbi_suspend,
							     idx, state);
}

static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
					  struct cpuidle_driver *drv, int idx,
					  bool s2idle)
{
	struct sbi_cpuidle_data *data = this_cpu_ptr(&sbi_cpuidle_data);
	u32 *states = data->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. */
	ct_irq_enter_irqson();
	if (s2idle)
		dev_pm_genpd_suspend(pd_dev);
	else
		pm_runtime_put_sync_suspend(pd_dev);
	ct_irq_exit_irqson();

	if (sbi_is_domain_state_available())
		state = sbi_get_domain_state();
	else
		state = states[idx];

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

	ct_irq_enter_irqson();
	if (s2idle)
		dev_pm_genpd_resume(pd_dev);
	else
		pm_runtime_get_sync(pd_dev);
	ct_irq_exit_irqson();

	cpu_pm_exit();

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

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

static int sbi_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
					      struct cpuidle_driver *drv,
					      int idx)
{
	return __sbi_enter_domain_idle_state(dev, drv, idx, true);
}

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

	if (pd_dev)
		pm_runtime_get_sync(pd_dev);

	return 0;
}

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

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

	return 0;
}

static void sbi_idle_init_cpuhp(void)
{
	int err;

	if (!sbi_cpuidle_use_cpuhp)
		return;

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

static const struct of_device_id sbi_cpuidle_state_match[] = {
	{ .compatible = "riscv,idle-state",
	  .data = sbi_cpuidle_enter_state },
	{ },
};

static bool sbi_suspend_state_is_valid(u32 state)
{
	if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
	    state < SBI_HSM_SUSPEND_RET_PLATFORM)
		return false;
	if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
	    state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
		return false;
	return true;
}

static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
{
	int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);

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

	if (!sbi_suspend_state_is_valid(*state)) {
		pr_warn("Invalid SBI suspend state %#x\n", *state);
		return -EINVAL;
	}

	return 0;
}

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

	data->dev = dt_idle_attach_cpu(cpu, "sbi");
	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 = sbi_enter_domain_idle_state;
	drv->states[state_count - 1].enter_s2idle =
					sbi_enter_s2idle_domain_idle_state;
	sbi_cpuidle_use_cpuhp = true;

	return 0;
}

static int sbi_cpuidle_dt_init_states(struct device *dev,
					struct cpuidle_driver *drv,
					unsigned int cpu,
					unsigned int state_count)
{
	struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
	struct device_node *state_node;
	struct device_node *cpu_node;
	u32 *states;
	int i, ret;

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

	states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);
	if (!states) {
		ret = -ENOMEM;
		goto fail;
	}

	/* Parse SBI specific details from state DT nodes */
	for (i = 1; i < state_count; i++) {
		state_node = of_get_cpu_state_node(cpu_node, i - 1);
		if (!state_node)
			break;

		ret = sbi_dt_parse_state_node(state_node, &states[i]);
		of_node_put(state_node);

		if (ret)
			return ret;

		pr_debug("sbi-state %#x index %d\n", states[i], i);
	}
	if (i != state_count) {
		ret = -ENODEV;
		goto fail;
	}

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

	/* Store states in the per-cpu struct. */
	data->states = states;

fail:
	of_node_put(cpu_node);

	return ret;
}

static void sbi_cpuidle_deinit_cpu(int cpu)
{
	struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);

	dt_idle_detach_cpu(data->dev);
	sbi_cpuidle_use_cpuhp = false;
}

static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
{
	struct cpuidle_driver *drv;
	unsigned int state_count = 0;
	int ret = 0;

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

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

	/* RISC-V architectural WFI to be represented as state index 0. */
	drv->states[0].enter = sbi_cpuidle_enter_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, "RISC-V 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, sbi_cpuidle_state_match, 1);
	if (ret <= 0) {
		pr_debug("HART%ld: failed to parse DT idle states\n",
			 cpuid_to_hartid_map(cpu));
		return ret ? : -ENODEV;
	}
	state_count = ret + 1; /* Include WFI state as well */

	/* Initialize idle states from DT. */
	ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);
	if (ret) {
		pr_err("HART%ld: failed to init idle states\n",
		       cpuid_to_hartid_map(cpu));
		return ret;
	}

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

	cpuidle_cooling_register(drv);

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

static void sbi_cpuidle_domain_sync_state(struct device *dev)
{
	/*
	 * All devices have now been attached/probed to the PM domain
	 * topology, hence it's fine to allow domain states to be picked.
	 */
	sbi_cpuidle_pd_allow_domain_state = true;
}

#ifdef CONFIG_DT_IDLE_GENPD

static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
{
	struct genpd_power_state *state = &pd->states[pd->state_idx];
	u32 *pd_state;

	if (!state->data)
		return 0;

	if (!sbi_cpuidle_pd_allow_domain_state)
		return -EBUSY;

	/* OSI mode is enabled, set the corresponding domain state. */
	pd_state = state->data;
	sbi_set_domain_state(*pd_state);

	return 0;
}

struct sbi_pd_provider {
	struct list_head link;
	struct device_node *node;
};

static LIST_HEAD(sbi_pd_providers);

static int sbi_pd_init(struct device_node *np)
{
	struct generic_pm_domain *pd;
	struct sbi_pd_provider *pd_provider;
	struct dev_power_governor *pd_gov;
	int ret = -ENOMEM;

	pd = dt_idle_pd_alloc(np, sbi_dt_parse_state_node);
	if (!pd)
		goto out;

	pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
	if (!pd_provider)
		goto free_pd;

	pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;

	/* Allow power off when OSI is available. */
	if (sbi_cpuidle_use_osi)
		pd->power_off = sbi_cpuidle_pd_power_off;
	else
		pd->flags |= GENPD_FLAG_ALWAYS_ON;

	/* Use governor for CPU PM domains if it has some states to manage. */
	pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;

	ret = pm_genpd_init(pd, pd_gov, false);
	if (ret)
		goto free_pd_prov;

	ret = of_genpd_add_provider_simple(np, pd);
	if (ret)
		goto remove_pd;

	pd_provider->node = of_node_get(np);
	list_add(&pd_provider->link, &sbi_pd_providers);

	pr_debug("init PM domain %s\n", pd->name);
	return 0;

remove_pd:
	pm_genpd_remove(pd);
free_pd_prov:
	kfree(pd_provider);
free_pd:
	dt_idle_pd_free(pd);
out:
	pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
	return ret;
}

static void sbi_pd_remove(void)
{
	struct sbi_pd_provider *pd_provider, *it;
	struct generic_pm_domain *genpd;

	list_for_each_entry_safe(pd_provider, it, &sbi_pd_providers, link) {
		of_genpd_del_provider(pd_provider->node);

		genpd = of_genpd_remove_last(pd_provider->node);
		if (!IS_ERR(genpd))
			kfree(genpd);

		of_node_put(pd_provider->node);
		list_del(&pd_provider->link);
		kfree(pd_provider);
	}
}

static int sbi_genpd_probe(struct device_node *np)
{
	struct device_node *node;
	int ret = 0, pd_count = 0;

	if (!np)
		return -ENODEV;

	/*
	 * Parse child nodes for the "#power-domain-cells" property and
	 * initialize a genpd/genpd-of-provider pair when it's found.
	 */
	for_each_child_of_node(np, node) {
		if (!of_find_property(node, "#power-domain-cells", NULL))
			continue;

		ret = sbi_pd_init(node);
		if (ret)
			goto put_node;

		pd_count++;
	}

	/* Bail out if not using the hierarchical CPU topology. */
	if (!pd_count)
		goto no_pd;

	/* Link genpd masters/subdomains to model the CPU topology. */
	ret = dt_idle_pd_init_topology(np);
	if (ret)
		goto remove_pd;

	return 0;

put_node:
	of_node_put(node);
remove_pd:
	sbi_pd_remove();
	pr_err("failed to create CPU PM domains ret=%d\n", ret);
no_pd:
	return ret;
}

#else

static inline int sbi_genpd_probe(struct device_node *np)
{
	return 0;
}

#endif

static int sbi_cpuidle_probe(struct platform_device *pdev)
{
	int cpu, ret;
	struct cpuidle_driver *drv;
	struct cpuidle_device *dev;
	struct device_node *np, *pds_node;

	/* Detect OSI support based on CPU DT nodes */
	sbi_cpuidle_use_osi = true;
	for_each_possible_cpu(cpu) {
		np = of_cpu_device_node_get(cpu);
		if (np &&
		    of_find_property(np, "power-domains", NULL) &&
		    of_find_property(np, "power-domain-names", NULL)) {
			continue;
		} else {
			sbi_cpuidle_use_osi = false;
			break;
		}
	}

	/* Populate generic power domains from DT nodes */
	pds_node = of_find_node_by_path("/cpus/power-domains");
	if (pds_node) {
		ret = sbi_genpd_probe(pds_node);
		of_node_put(pds_node);
		if (ret)
			return ret;
	}

	/* Initialize CPU idle driver for each CPU */
	for_each_possible_cpu(cpu) {
		ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
		if (ret) {
			pr_debug("HART%ld: idle driver init failed\n",
				 cpuid_to_hartid_map(cpu));
			goto out_fail;
		}
	}

	/* Setup CPU hotplut notifiers */
	sbi_idle_init_cpuhp();

	pr_info("idle driver registered for all CPUs\n");

	return 0;

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

	return ret;
}

static struct platform_driver sbi_cpuidle_driver = {
	.probe = sbi_cpuidle_probe,
	.driver = {
		.name = "sbi-cpuidle",
		.sync_state = sbi_cpuidle_domain_sync_state,
	},
};

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

	/*
	 * The SBI HSM suspend function is only available when:
	 * 1) SBI version is 0.3 or higher
	 * 2) SBI HSM extension is available
	 */
	if ((sbi_spec_version < sbi_mk_version(0, 3)) ||
	    sbi_probe_extension(SBI_EXT_HSM) <= 0) {
		pr_info("HSM suspend not available\n");
		return 0;
	}

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

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

	return 0;
}
device_initcall(sbi_cpuidle_init);