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Commit bd2d0a75 authored by Venkatesh Yadav Abbarapu's avatar Venkatesh Yadav Abbarapu
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arm: topology: Add support for topology DT bindings 



Add support for parsing the explicit topology bindings to discover the
topology of the system.

Change-Id: I7f8a62d243fe1452408ab696ea2714aaa5b929eb
Signed-off-by: default avatarVenkatesh Yadav Abbarapu <vabbar@codeaurora.org>
parent 3204cbe7

arch/arm/include/asm/topology.h

+2 −2
Original line number Diff line number Diff line
@@ -8,14 +8,14 @@ 
struct cputopo_arm {

	int thread_id;

	int core_id;

	int socket_id;

	int cluster_id;

	cpumask_t thread_sibling;

	cpumask_t core_sibling;

};



extern struct cputopo_arm cpu_topology[NR_CPUS];



#define topology_physical_package_id(cpu)	(cpu_topology[cpu].socket_id)

#define topology_physical_package_id(cpu)	(cpu_topology[cpu].cluster_id)

#define topology_core_id(cpu)		(cpu_topology[cpu].core_id)

#define topology_core_cpumask(cpu)	(&cpu_topology[cpu].core_sibling)

#define topology_thread_cpumask(cpu)	(&cpu_topology[cpu].thread_sibling)

arch/arm/kernel/topology.c

+196 −19
Original line number Diff line number Diff line
@@ -52,6 +52,144 @@ static void set_capacity_scale(unsigned int cpu, unsigned long capacity) 
	per_cpu(cpu_scale, cpu) = capacity;

}



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 -EINVAL;



	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 -EINVAL;

}



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;

	int core_id = 0;

	int i, ret;

	static int cluster_id __initdata;



	/*

	* 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;

}



#ifdef CONFIG_OF

struct cpu_efficiency {

	const char *compatible;
@@ -87,14 +225,40 @@ static unsigned long middle_capacity = 1; 
 * 'average' CPU is of middle capacity. Also see the comments near

 * table_efficiency[] and update_cpu_capacity().

 */

static void __init parse_dt_topology(void)

static int __init parse_dt_topology(void)

{

	const struct cpu_efficiency *cpu_eff;

	struct device_node *cn = NULL;

	struct device_node *cn = NULL, *map;

	unsigned long min_capacity = ULONG_MAX;

	unsigned long max_capacity = 0;

	unsigned long capacity = 0;

	int cpu = 0;

	int cpu = 0, ret = 0;



	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;



	__cpu_capacity = kcalloc(nr_cpu_ids, sizeof(*__cpu_capacity),

				 GFP_NOWAIT);
@@ -150,7 +314,11 @@ static void __init parse_dt_topology(void) 
	else

		middle_capacity = ((max_capacity / 3)

				>> (SCHED_CAPACITY_SHIFT-1)) + 1;



out_map:

	of_node_put(map);

out:

	of_node_put(cn);

	return ret;

}



/*
@@ -170,7 +338,7 @@ static void update_cpu_capacity(unsigned int cpu) 
}



#else

static inline void parse_dt_topology(void) {}

static inline int parse_dt_topology(void) {}

static inline void update_cpu_capacity(unsigned int cpuid) {}

#endif
@@ -203,7 +371,7 @@ static void update_siblings_masks(unsigned int cpuid) 
	for_each_possible_cpu(cpu) {

		cpu_topo = &cpu_topology[cpu];



		if (cpuid_topo->socket_id != cpu_topo->socket_id)

		if (cpuid_topo->cluster_id != cpu_topo->cluster_id)

			continue;



		cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
@@ -230,9 +398,8 @@ void store_cpu_topology(unsigned int cpuid) 
	struct cputopo_arm *cpuid_topo = &cpu_topology[cpuid];

	unsigned int mpidr;



	/* If the cpu topology has been already set, just return */

	if (cpuid_topo->core_id != -1)

		return;

		goto topology_populated;



	mpidr = read_cpuid_mpidr();
@@ -247,12 +414,12 @@ void store_cpu_topology(unsigned int cpuid) 
			/* core performance interdependency */

			cpuid_topo->thread_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);

			cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 1);

			cpuid_topo->socket_id = MPIDR_AFFINITY_LEVEL(mpidr, 2);

			cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 2);

		} else {

			/* largely independent cores */

			cpuid_topo->thread_id = -1;

			cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);

			cpuid_topo->socket_id = MPIDR_AFFINITY_LEVEL(mpidr, 1);

			cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 1);

		}

	} else {

		/*
@@ -262,17 +429,17 @@ void store_cpu_topology(unsigned int cpuid) 
		 */

		cpuid_topo->thread_id = -1;

		cpuid_topo->core_id = 0;

		cpuid_topo->socket_id = -1;

		cpuid_topo->cluster_id = -1;

	}



	update_siblings_masks(cpuid);



	update_cpu_capacity(cpuid);



	printk(KERN_INFO "CPU%u: thread %d, cpu %d, socket %d, mpidr %x\n",

	pr_info("CPU%u: thread %d, cpu %d, cluster %d, mpidr %x\n",

		cpuid, cpu_topology[cpuid].thread_id,

		cpu_topology[cpuid].core_id,

		cpu_topology[cpuid].socket_id, mpidr);

		cpu_topology[cpuid].cluster_id, mpidr);



topology_populated:

	update_siblings_masks(cpuid);

	update_cpu_capacity(cpuid);

}



static inline int cpu_corepower_flags(void)
@@ -303,7 +470,7 @@ void __init init_cpu_topology(void) 


		cpu_topo->thread_id = -1;

		cpu_topo->core_id =  -1;

		cpu_topo->socket_id = -1;

		cpu_topo->cluster_id = -1;

		cpumask_clear(&cpu_topo->core_sibling);

		cpumask_clear(&cpu_topo->thread_sibling);
@@ -311,7 +478,17 @@ void __init init_cpu_topology(void) 
	}

	smp_wmb();



	parse_dt_topology();

	if (parse_dt_topology()) {

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



		cpu_topo->thread_id = -1;

		cpu_topo->core_id =  -1;

		cpu_topo->cluster_id = -1;

		cpumask_clear(&cpu_topo->core_sibling);

		cpumask_clear(&cpu_topo->thread_sibling);



		set_capacity_scale(cpu, SCHED_CAPACITY_SCALE);

	}



	/* Set scheduler topology descriptor */

	set_sched_topology(arm_topology);