1 files changed, 118 insertions, 0 deletions
diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
new file mode 100644
index 000000000..e133011f6
--- /dev/null
+++ b/arch/arm64/kernel/cpu_ops.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CPU kernel entry/exit control
+ *
+ * Copyright (C) 2013 ARM Ltd.
+ */
+
+#include <linux/acpi.h>
+#include <linux/cache.h>
+#include <linux/errno.h>
+#include <linux/of.h>
+#include <linux/string.h>
+#include <asm/acpi.h>
+#include <asm/cpu_ops.h>
+#include <asm/smp_plat.h>
+
+extern const struct cpu_operations smp_spin_table_ops;
+#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
+extern const struct cpu_operations acpi_parking_protocol_ops;
+#endif
+extern const struct cpu_operations cpu_psci_ops;
+
+static const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
+
+static const struct cpu_operations *const dt_supported_cpu_ops[] __initconst = {
+	&smp_spin_table_ops,
+	&cpu_psci_ops,
+	NULL,
+};
+
+static const struct cpu_operations *const acpi_supported_cpu_ops[] __initconst = {
+#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
+	&acpi_parking_protocol_ops,
+#endif
+	&cpu_psci_ops,
+	NULL,
+};
+
+static const struct cpu_operations * __init cpu_get_ops(const char *name)
+{
+	const struct cpu_operations *const *ops;
+
+	ops = acpi_disabled ? dt_supported_cpu_ops : acpi_supported_cpu_ops;
+
+	while (*ops) {
+		if (!strcmp(name, (*ops)->name))
+			return *ops;
+
+		ops++;
+	}
+
+	return NULL;
+}
+
+static const char *__init cpu_read_enable_method(int cpu)
+{
+	const char *enable_method;
+
+	if (acpi_disabled) {
+		struct device_node *dn = of_get_cpu_node(cpu, NULL);
+
+		if (!dn) {
+			if (!cpu)
+				pr_err("Failed to find device node for boot cpu\n");
+			return NULL;
+		}
+
+		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("%pOF: missing enable-method property\n",
+					dn);
+		}
+		of_node_put(dn);
+	} else {
+		enable_method = acpi_get_enable_method(cpu);
+		if (!enable_method) {
+			/*
+			 * In ACPI systems the boot CPU does not require
+			 * checking the enable method since for some
+			 * boot protocol (ie parking protocol) it need not
+			 * be initialized. Don't warn spuriously.
+			 */
+			if (cpu != 0)
+				pr_err("Unsupported ACPI enable-method\n");
+		}
+	}
+
+	return enable_method;
+}
+/*
+ * Read a cpu's enable method and record it in cpu_ops.
+ */
+int __init init_cpu_ops(int cpu)
+{
+	const char *enable_method = cpu_read_enable_method(cpu);
+
+	if (!enable_method)
+		return -ENODEV;
+
+	cpu_ops[cpu] = cpu_get_ops(enable_method);
+	if (!cpu_ops[cpu]) {
+		pr_warn("Unsupported enable-method: %s\n", enable_method);
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+const struct cpu_operations *get_cpu_ops(int cpu)
+{
+	return cpu_ops[cpu];
+}