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authorMark Brown <broonie@linaro.org>2013-12-11 12:45:29 +0000
committerMark Brown <broonie@linaro.org>2013-12-11 20:15:58 +0000
commit03f72c345aa91c511c94331a6417312afd467e3f (patch)
treed5fcad7d252cf01b92b43628fa3e5c100f1d6850
parent8041498123406e6d610c341301c8aa3001ed98d9 (diff)
downloadlinux-linaro-stable-v3.10/topic/topology.tar.gz
arm64: topology: Add support for topology DT bindingsv3.10/topic/topology
Add support for parsing the explicit topology bindings to discover the topology of the system. Since it is not currently clear how to map multi-level clusters for the scheduler all leaf clusters are presented to the scheduler at the same level. This should be enough to provide good support for current systems. Signed-off-by: Mark Brown <broonie@linaro.org>
-rw-r--r--arch/arm64/kernel/topology.c130
1 files changed, 130 insertions, 0 deletions
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index c88970b..83d6919 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -79,6 +79,121 @@ static unsigned long *__cpu_capacity;
#define cpu_capacity(cpu) __cpu_capacity[cpu]
static unsigned long middle_capacity = 1;
+static int cluster_id;
+
+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) {
+ pr_crit("%s: Unable to parse CPU phandle\n", node->full_name);
+ return -1;
+ }
+
+ for_each_possible_cpu(cpu) {
+ if (of_get_cpu_node(cpu, NULL) == cpu_node)
+ return cpu;
+ }
+
+ pr_crit("Unable to find CPU node for %s\n", cpu_node->full_name);
+ return -1;
+}
+
+static void __init parse_core(struct device_node *core, int core_id)
+{
+ char name[10];
+ bool leaf = true;
+ int i, cpu;
+ struct device_node *t;
+
+ i = 0;
+ 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) {
+ pr_info("CPU%d: socket %d core %d thread %d\n",
+ cpu, cluster_id, core_id, i);
+ cpu_topology[cpu].socket_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);
+ }
+ }
+ 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;
+ }
+
+ pr_info("CPU%d: socket %d core %d\n",
+ cpu, cluster_id, core_id);
+ cpu_topology[cpu].socket_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);
+ }
+}
+
+static void __init parse_cluster(struct device_node *cluster)
+{
+ char name[10];
+ bool leaf = true;
+ bool has_cores = false;
+ struct device_node *c;
+ int core_id = 0;
+ int i;
+
+ /*
+ * 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) {
+ parse_cluster(c);
+ leaf = false;
+ }
+ 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 (leaf)
+ parse_core(c, core_id++);
+ else
+ pr_err("%s: Non-leaf cluster with core %s\n",
+ cluster->full_name, name);
+ }
+ i++;
+ } while (c);
+
+ if (leaf && !has_cores)
+ pr_warn("%s: empty cluster\n", cluster->full_name);
+
+ if (leaf)
+ cluster_id++;
+}
/*
* Iterate all CPUs' descriptor in DT and compute the efficiency
@@ -100,6 +215,21 @@ static void __init parse_dt_topology(void)
alloc_size = nr_cpu_ids * sizeof(*__cpu_capacity);
__cpu_capacity = kzalloc(alloc_size, GFP_NOWAIT);
+ cn = of_find_node_by_path("/cpus");
+ if (!cn) {
+ pr_err("No CPU information found in DT\n");
+ return;
+ }
+
+ /*
+ * If topology is provided as a cpu-map it is essentially a
+ * root cluster.
+ */
+ cn = of_find_node_by_name(cn, "cpu-map");
+ if (!cn)
+ return;
+ parse_cluster(cn);
+
for_each_possible_cpu(cpu) {
const u32 *rate;
int len;