1/*
 2 * arch/arm64/kernel/topology.c
 3 *
 4 * Copyright (C) 2011,2013,2014 Linaro Limited.
 5 *
 6 * Based on the arm32 version written by Vincent Guittot in turn based on
 7 * arch/sh/kernel/topology.c
 8 *
 9 * This file is subject to the terms and conditions of the GNU General Public
10 * License.  See the file "COPYING" in the main directory of this archive
11 * for more details.
12 */
13
14#include <linux/cpu.h>
15#include <linux/cpumask.h>
16#include <linux/init.h>
17#include <linux/percpu.h>
18#include <linux/node.h>
19#include <linux/nodemask.h>
20#include <linux/sched.h>
21
22#include <asm/topology.h>
23
24/*
25 * cpu topology table
26 */
27struct cpu_topology cpu_topology[NR_CPUS];
28EXPORT_SYMBOL_GPL(cpu_topology);
29
30const struct cpumask *cpu_coregroup_mask(int cpu)
31{
32	return &cpu_topology[cpu].core_sibling;
33}
34
35static void update_siblings_masks(unsigned int cpuid)
36{
37	struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
38	int cpu;
39
40	if (cpuid_topo->cluster_id == -1) {
41		/*
42		 * DT does not contain topology information for this cpu
43		 * reset it to default behaviour
44		 */
45		pr_debug("CPU%u: No topology information configured\n", cpuid);
46		cpuid_topo->core_id = 0;
47		cpumask_set_cpu(cpuid, &cpuid_topo->core_sibling);
48		cpumask_set_cpu(cpuid, &cpuid_topo->thread_sibling);
49		return;
50	}
51
52	/* update core and thread sibling masks */
53	for_each_possible_cpu(cpu) {
54		cpu_topo = &cpu_topology[cpu];
55
56		if (cpuid_topo->cluster_id != cpu_topo->cluster_id)
57			continue;
58
59		cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
60		if (cpu != cpuid)
61			cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
62
63		if (cpuid_topo->core_id != cpu_topo->core_id)
64			continue;
65
66		cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
67		if (cpu != cpuid)
68			cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
69	}
70}
71
72void store_cpu_topology(unsigned int cpuid)
73{
74	update_siblings_masks(cpuid);
75}
76
77/*
78 * init_cpu_topology is called at boot when only one cpu is running
79 * which prevent simultaneous write access to cpu_topology array
80 */
81void __init init_cpu_topology(void)
82{
83	unsigned int cpu;
84
85	/* init core mask and power*/
86	for_each_possible_cpu(cpu) {
87		struct cpu_topology *cpu_topo = &cpu_topology[cpu];
88
89		cpu_topo->thread_id = -1;
90		cpu_topo->core_id =  -1;
91		cpu_topo->cluster_id = -1;
92		cpumask_clear(&cpu_topo->core_sibling);
93		cpumask_clear(&cpu_topo->thread_sibling);
94	}
95}