summaryrefslogtreecommitdiffstats
path: root/drivers/base/arch_topology.c
blob: 4d0a0038b476e4a6d12ff980f5f882b8cb8e4d03 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Arch specific cpu topology information
 *
 * Copyright (C) 2016, ARM Ltd.
 * Written by: Juri Lelli, ARM Ltd.
 */

#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sched/topology.h>
#include <linux/cpuset.h>
#include <linux/cpumask.h>
#include <linux/init.h>
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/smp.h>

__weak bool arch_freq_counters_available(struct cpumask *cpus)
{
	return false;
}
DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;

void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
			 unsigned long max_freq)
{
	unsigned long scale;
	int i;

	/*
	 * If the use of counters for FIE is enabled, just return as we don't
	 * want to update the scale factor with information from CPUFREQ.
	 * Instead the scale factor will be updated from arch_scale_freq_tick.
	 */
	if (arch_freq_counters_available(cpus))
		return;

	scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;

	for_each_cpu(i, cpus)
		per_cpu(freq_scale, i) = scale;
}

DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;

void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
{
	per_cpu(cpu_scale, cpu) = capacity;
}

static ssize_t cpu_capacity_show(struct device *dev,
				 struct device_attribute *attr,
				 char *buf)
{
	struct cpu *cpu = container_of(dev, struct cpu, dev);

	return sprintf(buf, "%lu\n", topology_get_cpu_scale(cpu->dev.id));
}

static void update_topology_flags_workfn(struct work_struct *work);
static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn);

static DEVICE_ATTR_RO(cpu_capacity);

static int register_cpu_capacity_sysctl(void)
{
	int i;
	struct device *cpu;

	for_each_possible_cpu(i) {
		cpu = get_cpu_device(i);
		if (!cpu) {
			pr_err("%s: too early to get CPU%d device!\n",
			       __func__, i);
			continue;
		}
		device_create_file(cpu, &dev_attr_cpu_capacity);
	}

	return 0;
}
subsys_initcall(register_cpu_capacity_sysctl);

static int update_topology;

int topology_update_cpu_topology(void)
{
	return update_topology;
}

/*
 * Updating the sched_domains can't be done directly from cpufreq callbacks
 * due to locking, so queue the work for later.
 */
static void update_topology_flags_workfn(struct work_struct *work)
{
	update_topology = 1;
	rebuild_sched_domains();
	pr_debug("sched_domain hierarchy rebuilt, flags updated\n");
	update_topology = 0;
}

static DEFINE_PER_CPU(u32, freq_factor) = 1;
static u32 *raw_capacity;

static int free_raw_capacity(void)
{
	kfree(raw_capacity);
	raw_capacity = NULL;

	return 0;
}

void topology_normalize_cpu_scale(void)
{
	u64 capacity;
	u64 capacity_scale;
	int cpu;

	if (!raw_capacity)
		return;

	capacity_scale = 1;
	for_each_possible_cpu(cpu) {
		capacity = raw_capacity[cpu] * per_cpu(freq_factor, cpu);
		capacity_scale = max(capacity, capacity_scale);
	}

	pr_debug("cpu_capacity: capacity_scale=%llu\n", capacity_scale);
	for_each_possible_cpu(cpu) {
		capacity = raw_capacity[cpu] * per_cpu(freq_factor, cpu);
		capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT,
			capacity_scale);
		topology_set_cpu_scale(cpu, capacity);
		pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
			cpu, topology_get_cpu_scale(cpu));
	}
}

bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
{
	struct clk *cpu_clk;
	static bool cap_parsing_failed;
	int ret;
	u32 cpu_capacity;

	if (cap_parsing_failed)
		return false;

	ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
				   &cpu_capacity);
	if (!ret) {
		if (!raw_capacity) {
			raw_capacity = kcalloc(num_possible_cpus(),
					       sizeof(*raw_capacity),
					       GFP_KERNEL);
			if (!raw_capacity) {
				cap_parsing_failed = true;
				return false;
			}
		}
		raw_capacity[cpu] = cpu_capacity;
		pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
			cpu_node, raw_capacity[cpu]);

		/*
		 * Update freq_factor for calculating early boot cpu capacities.
		 * For non-clk CPU DVFS mechanism, there's no way to get the
		 * frequency value now, assuming they are running at the same
		 * frequency (by keeping the initial freq_factor value).
		 */
		cpu_clk = of_clk_get(cpu_node, 0);
		if (!PTR_ERR_OR_ZERO(cpu_clk)) {
			per_cpu(freq_factor, cpu) =
				clk_get_rate(cpu_clk) / 1000;
			clk_put(cpu_clk);
		}
	} else {
		if (raw_capacity) {
			pr_err("cpu_capacity: missing %pOF raw capacity\n",
				cpu_node);
			pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
		}
		cap_parsing_failed = true;
		free_raw_capacity();
	}

	return !ret;
}

#ifdef CONFIG_CPU_FREQ
static cpumask_var_t cpus_to_visit;
static void parsing_done_workfn(struct work_struct *work);
static DECLARE_WORK(parsing_done_work, parsing_done_workfn);

static int
init_cpu_capacity_callback(struct notifier_block *nb,
			   unsigned long val,
			   void *data)
{
	struct cpufreq_policy *policy = data;
	int cpu;

	if (!raw_capacity)
		return 0;

	if (val != CPUFREQ_CREATE_POLICY)
		return 0;

	pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
		 cpumask_pr_args(policy->related_cpus),
		 cpumask_pr_args(cpus_to_visit));

	cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);

	for_each_cpu(cpu, policy->related_cpus)
		per_cpu(freq_factor, cpu) = policy->cpuinfo.max_freq / 1000;

	if (cpumask_empty(cpus_to_visit)) {
		topology_normalize_cpu_scale();
		schedule_work(&update_topology_flags_work);
		free_raw_capacity();
		pr_debug("cpu_capacity: parsing done\n");
		schedule_work(&parsing_done_work);
	}

	return 0;
}

static struct notifier_block init_cpu_capacity_notifier = {
	.notifier_call = init_cpu_capacity_callback,
};

static int __init register_cpufreq_notifier(void)
{
	int ret;

	/*
	 * on ACPI-based systems we need to use the default cpu capacity
	 * until we have the necessary code to parse the cpu capacity, so
	 * skip registering cpufreq notifier.
	 */
	if (!acpi_disabled || !raw_capacity)
		return -EINVAL;

	if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL))
		return -ENOMEM;

	cpumask_copy(cpus_to_visit, cpu_possible_mask);

	ret = cpufreq_register_notifier(&init_cpu_capacity_notifier,
					CPUFREQ_POLICY_NOTIFIER);

	if (ret)
		free_cpumask_var(cpus_to_visit);

	return ret;
}
core_initcall(register_cpufreq_notifier);

static void parsing_done_workfn(struct work_struct *work)
{
	cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
					 CPUFREQ_POLICY_NOTIFIER);
	free_cpumask_var(cpus_to_visit);
}

#else
core_initcall(free_raw_capacity);
#endif

#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
/*
 * This function returns the logic cpu number of the node.
 * There are basically three kinds of return values:
 * (1) logic cpu number which is > 0.
 * (2) -ENODEV when the device tree(DT) node is valid and found in the DT but
 * there is no possible logical CPU in the kernel to match. This happens
 * when CONFIG_NR_CPUS is configure to be smaller than the number of
 * CPU nodes in DT. We need to just ignore this case.
 * (3) -1 if the node does not exist in the device tree
 */
static int __init get_cpu_for_node(struct device_node *node)
{
	struct device_node *cpu_node;
	int cpu;

	cpu_node = of_parse_phandle(node, "cpu", 0);
	if (!cpu_node)
		return -1;

	cpu = of_cpu_node_to_id(cpu_node);
	if (cpu >= 0)
		topology_parse_cpu_capacity(cpu_node, cpu);
	else
		pr_info("CPU node for %pOF exist but the possible cpu range is :%*pbl\n",
			cpu_node, cpumask_pr_args(cpu_possible_mask));

	of_node_put(cpu_node);
	return cpu;
}

static int __init parse_core(struct device_node *core, int package_id,
			     int core_id)
{
	char name[20];
	bool leaf = true;
	int i = 0;
	int cpu;
	struct device_node *t;

	do {
		snprintf(name, sizeof(name), "thread%d", i);
		t = of_get_child_by_name(core, name);
		if (t) {
			leaf = false;
			cpu = get_cpu_for_node(t);
			if (cpu >= 0) {
				cpu_topology[cpu].package_id = package_id;
				cpu_topology[cpu].core_id = core_id;
				cpu_topology[cpu].thread_id = i;
			} else if (cpu != -ENODEV) {
				pr_err("%pOF: Can't get CPU for thread\n", t);
				of_node_put(t);
				return -EINVAL;
			}
			of_node_put(t);
		}
		i++;
	} while (t);

	cpu = get_cpu_for_node(core);
	if (cpu >= 0) {
		if (!leaf) {
			pr_err("%pOF: Core has both threads and CPU\n",
			       core);
			return -EINVAL;
		}

		cpu_topology[cpu].package_id = package_id;
		cpu_topology[cpu].core_id = core_id;
	} else if (leaf && cpu != -ENODEV) {
		pr_err("%pOF: Can't get CPU for leaf core\n", core);
		return -EINVAL;
	}

	return 0;
}

static int __init parse_cluster(struct device_node *cluster, int depth)
{
	char name[20];
	bool leaf = true;
	bool has_cores = false;
	struct device_node *c;
	static int package_id __initdata;
	int core_id = 0;
	int i, ret;

	/*
	 * First check for child clusters; we currently ignore any
	 * information about the nesting of clusters and present the
	 * scheduler with a flat list of them.
	 */
	i = 0;
	do {
		snprintf(name, sizeof(name), "cluster%d", i);
		c = of_get_child_by_name(cluster, name);
		if (c) {
			leaf = false;
			ret = parse_cluster(c, depth + 1);
			of_node_put(c);
			if (ret != 0)
				return ret;
		}
		i++;
	} while (c);

	/* Now check for cores */
	i = 0;
	do {
		snprintf(name, sizeof(name), "core%d", i);
		c = of_get_child_by_name(cluster, name);
		if (c) {
			has_cores = true;

			if (depth == 0) {
				pr_err("%pOF: cpu-map children should be clusters\n",
				       c);
				of_node_put(c);
				return -EINVAL;
			}

			if (leaf) {
				ret = parse_core(c, package_id, core_id++);
			} else {
				pr_err("%pOF: Non-leaf cluster with core %s\n",
				       cluster, name);
				ret = -EINVAL;
			}

			of_node_put(c);
			if (ret != 0)
				return ret;
		}
		i++;
	} while (c);

	if (leaf && !has_cores)
		pr_warn("%pOF: empty cluster\n", cluster);

	if (leaf)
		package_id++;

	return 0;
}

static int __init parse_dt_topology(void)
{
	struct device_node *cn, *map;
	int ret = 0;
	int cpu;

	cn = of_find_node_by_path("/cpus");
	if (!cn) {
		pr_err("No CPU information found in DT\n");
		return 0;
	}

	/*
	 * When topology is provided cpu-map is essentially a root
	 * cluster with restricted subnodes.
	 */
	map = of_get_child_by_name(cn, "cpu-map");
	if (!map)
		goto out;

	ret = parse_cluster(map, 0);
	if (ret != 0)
		goto out_map;

	topology_normalize_cpu_scale();

	/*
	 * Check that all cores are in the topology; the SMP code will
	 * only mark cores described in the DT as possible.
	 */
	for_each_possible_cpu(cpu)
		if (cpu_topology[cpu].package_id == -1)
			ret = -EINVAL;

out_map:
	of_node_put(map);
out:
	of_node_put(cn);
	return ret;
}
#endif

/*
 * cpu topology table
 */
struct cpu_topology cpu_topology[NR_CPUS];
EXPORT_SYMBOL_GPL(cpu_topology);

const struct cpumask *cpu_coregroup_mask(int cpu)
{
	const cpumask_t *core_mask = cpumask_of_node(cpu_to_node(cpu));

	/* Find the smaller of NUMA, core or LLC siblings */
	if (cpumask_subset(&cpu_topology[cpu].core_sibling, core_mask)) {
		/* not numa in package, lets use the package siblings */
		core_mask = &cpu_topology[cpu].core_sibling;
	}
	if (cpu_topology[cpu].llc_id != -1) {
		if (cpumask_subset(&cpu_topology[cpu].llc_sibling, core_mask))
			core_mask = &cpu_topology[cpu].llc_sibling;
	}

	return core_mask;
}

void update_siblings_masks(unsigned int cpuid)
{
	struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
	int cpu;

	/* update core and thread sibling masks */
	for_each_online_cpu(cpu) {
		cpu_topo = &cpu_topology[cpu];

		if (cpuid_topo->llc_id == cpu_topo->llc_id) {
			cpumask_set_cpu(cpu, &cpuid_topo->llc_sibling);
			cpumask_set_cpu(cpuid, &cpu_topo->llc_sibling);
		}

		if (cpuid_topo->package_id != cpu_topo->package_id)
			continue;

		cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
		cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);

		if (cpuid_topo->core_id != cpu_topo->core_id)
			continue;

		cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
		cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
	}
}

static void clear_cpu_topology(int cpu)
{
	struct cpu_topology *cpu_topo = &cpu_topology[cpu];

	cpumask_clear(&cpu_topo->llc_sibling);
	cpumask_set_cpu(cpu, &cpu_topo->llc_sibling);

	cpumask_clear(&cpu_topo->core_sibling);
	cpumask_set_cpu(cpu, &cpu_topo->core_sibling);
	cpumask_clear(&cpu_topo->thread_sibling);
	cpumask_set_cpu(cpu, &cpu_topo->thread_sibling);
}

void __init reset_cpu_topology(void)
{
	unsigned int cpu;

	for_each_possible_cpu(cpu) {
		struct cpu_topology *cpu_topo = &cpu_topology[cpu];

		cpu_topo->thread_id = -1;
		cpu_topo->core_id = -1;
		cpu_topo->package_id = -1;
		cpu_topo->llc_id = -1;

		clear_cpu_topology(cpu);
	}
}

void remove_cpu_topology(unsigned int cpu)
{
	int sibling;

	for_each_cpu(sibling, topology_core_cpumask(cpu))
		cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
	for_each_cpu(sibling, topology_sibling_cpumask(cpu))
		cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
	for_each_cpu(sibling, topology_llc_cpumask(cpu))
		cpumask_clear_cpu(cpu, topology_llc_cpumask(sibling));

	clear_cpu_topology(cpu);
}

__weak int __init parse_acpi_topology(void)
{
	return 0;
}

#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
void __init init_cpu_topology(void)
{
	reset_cpu_topology();

	/*
	 * Discard anything that was parsed if we hit an error so we
	 * don't use partial information.
	 */
	if (parse_acpi_topology())
		reset_cpu_topology();
	else if (of_have_populated_dt() && parse_dt_topology())
		reset_cpu_topology();
}
#endif