arch/arm64/kernel/topology.c - linux - Git at Google

 /*
  * 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 (parse_dt_topology())
 		reset_cpu_topology();
 }
	/*
	* 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 (parse_dt_topology())
	reset_cpu_topology();
	}