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authorMark Brown <broonie@linaro.org>2013-12-11 12:45:29 +0000
committerMark Brown <broonie@linaro.org>2013-12-11 22:33:09 +0000
commite101473817ddc5e10919e4e22c3b421a350ad742 (patch)
tree3cd6f3ddc187b4e3ef8e7ac6443016ac3bbd0dda
parent66f06c94717c696fee2fa3ba139e8ffe226758ec (diff)
downloadlinux-linaro-stable-e101473817ddc5e10919e4e22c3b421a350ad742.tar.gz
arm64: topology: Add support for topology DT bindings
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 c88970b1b863..83d6919d4e0a 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;