1 files changed, 53 insertions, 1 deletions

diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
index e2652aadd9ea..aa0c9e78dbe1 100644
--- a/arch/arm64/kernel/cpu_ops.c
+++ b/arch/arm64/kernel/cpu_ops.c
@@ -17,6 +17,9 @@
  */
 
 #include <asm/cpu_ops.h>
+#include <asm/smp_plat.h>
+#include <linux/errno.h>
+#include <linux/of.h>
 #include <linux/string.h>
 
 extern const struct cpu_operations smp_spin_table_ops;
@@ -32,7 +35,7 @@ static const struct cpu_operations *supported_cpu_ops[] __initconst = {
 	NULL,
 };
 
-const struct cpu_operations * __init cpu_get_ops(const char *name)
+static const struct cpu_operations * __init cpu_get_ops(const char *name)
 {
 	const struct cpu_operations **ops = supported_cpu_ops;
 
@@ -45,3 +48,52 @@ const struct cpu_operations * __init cpu_get_ops(const char *name)
 
 	return NULL;
 }
+
+/*
+ * Read a cpu's enable method from the device tree and record it in cpu_ops.
+ */
+int __init cpu_read_ops(struct device_node *dn, int cpu)
+{
+	const char *enable_method = of_get_property(dn, "enable-method", NULL);
+	if (!enable_method) {
+		/*
+		 * The boot CPU may not have an enable method (e.g. when
+		 * spin-table is used for secondaries). Don't warn spuriously.
+		 */
+		if (cpu != 0)
+			pr_err("%s: missing enable-method property\n",
+				dn->full_name);
+		return -ENOENT;
+	}
+
+	cpu_ops[cpu] = cpu_get_ops(enable_method);
+	if (!cpu_ops[cpu]) {
+		pr_err("%s: invalid enable-method property: %s\n",
+		       dn->full_name, enable_method);
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+void __init cpu_read_bootcpu_ops(void)
+{
+	struct device_node *dn = NULL;
+	u64 mpidr = cpu_logical_map(0);
+
+	while ((dn = of_find_node_by_type(dn, "cpu"))) {
+		u64 hwid;
+		const __be32 *prop;
+
+		prop = of_get_property(dn, "reg", NULL);
+		if (!prop)
+			continue;
+
+		hwid = of_read_number(prop, of_n_addr_cells(dn));
+		if (hwid == mpidr) {
+			cpu_read_ops(dn, 0);
+			of_node_put(dn);
+			return;
+		}
+	}
+}