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- /*
- * arch/arm64/kernel/topology.c
- *
- * Copyright (C) 2011,2013,2014 Linaro Limited.
- *
- * Based on the arm32 version written by Vincent Guittot in turn based on
- * arch/sh/kernel/topology.c
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- */
- #include <linux/cpu.h>
- #include <linux/cpumask.h>
- #include <linux/init.h>
- #include <linux/percpu.h>
- #include <linux/node.h>
- #include <linux/nodemask.h>
- #include <linux/of.h>
- #include <linux/sched.h>
- #include <asm/cputype.h>
- #include <asm/topology.h>
- 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;
- for_each_possible_cpu(cpu) {
- if (of_get_cpu_node(cpu, NULL) == cpu_node) {
- of_node_put(cpu_node);
- return cpu;
- }
- }
- pr_crit("Unable to find CPU node for %s\n", cpu_node->full_name);
- of_node_put(cpu_node);
- return -1;
- }
- static int __init parse_core(struct device_node *core, int cluster_id,
- int core_id)
- {
- char name[10];
- 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].cluster_id = cluster_id;
- cpu_topology[cpu].core_id = core_id;
- cpu_topology[cpu].thread_id = i;
- } else {
- pr_err("%s: Can't get CPU for thread\n",
- t->full_name);
- 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("%s: Core has both threads and CPU\n",
- core->full_name);
- return -EINVAL;
- }
- cpu_topology[cpu].cluster_id = cluster_id;
- cpu_topology[cpu].core_id = core_id;
- } else if (leaf) {
- pr_err("%s: Can't get CPU for leaf core\n", core->full_name);
- return -EINVAL;
- }
- return 0;
- }
- static int __init parse_cluster(struct device_node *cluster, int depth)
- {
- char name[10];
- bool leaf = true;
- bool has_cores = false;
- struct device_node *c;
- static int cluster_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("%s: cpu-map children should be clusters\n",
- c->full_name);
- of_node_put(c);
- return -EINVAL;
- }
- if (leaf) {
- ret = parse_core(c, cluster_id, core_id++);
- } else {
- pr_err("%s: Non-leaf cluster with core %s\n",
- cluster->full_name, name);
- ret = -EINVAL;
- }
- of_node_put(c);
- if (ret != 0)
- return ret;
- }
- i++;
- } while (c);
- if (leaf && !has_cores)
- pr_warn("%s: empty cluster\n", cluster->full_name);
- if (leaf)
- cluster_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;
- /*
- * 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].cluster_id == -1)
- ret = -EINVAL;
- out_map:
- of_node_put(map);
- out:
- of_node_put(cn);
- return ret;
- }
- /*
- * cpu topology table
- */
- struct cpu_topology cpu_topology[NR_CPUS];
- EXPORT_SYMBOL_GPL(cpu_topology);
- const struct cpumask *cpu_coregroup_mask(int cpu)
- {
- return &cpu_topology[cpu].core_sibling;
- }
- static 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_possible_cpu(cpu) {
- cpu_topo = &cpu_topology[cpu];
- if (cpuid_topo->cluster_id != cpu_topo->cluster_id)
- continue;
- cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
- if (cpu != cpuid)
- 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);
- if (cpu != cpuid)
- cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
- }
- }
- void store_cpu_topology(unsigned int cpuid)
- {
- struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
- u64 mpidr;
- if (cpuid_topo->cluster_id != -1)
- goto topology_populated;
- mpidr = read_cpuid_mpidr();
- /* Uniprocessor systems can rely on default topology values */
- if (mpidr & MPIDR_UP_BITMASK)
- return;
- /* Create cpu topology mapping based on MPIDR. */
- if (mpidr & MPIDR_MT_BITMASK) {
- /* Multiprocessor system : Multi-threads per core */
- cpuid_topo->thread_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);
- cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 1);
- cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 2) |
- MPIDR_AFFINITY_LEVEL(mpidr, 3) << 8;
- } else {
- /* Multiprocessor system : Single-thread per core */
- cpuid_topo->thread_id = -1;
- cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);
- cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 1) |
- MPIDR_AFFINITY_LEVEL(mpidr, 2) << 8 |
- MPIDR_AFFINITY_LEVEL(mpidr, 3) << 16;
- }
- pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n",
- cpuid, cpuid_topo->cluster_id, cpuid_topo->core_id,
- cpuid_topo->thread_id, mpidr);
- topology_populated:
- update_siblings_masks(cpuid);
- }
- static 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 = 0;
- cpu_topo->cluster_id = -1;
- 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 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 (of_have_populated_dt() && parse_dt_topology())
- reset_cpu_topology();
- }
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