LoongArch: Add multi-processor (SMP) support

LoongArch-based procesors have 4, 8 or 16 cores per package. This patch
adds multi-processor (SMP) support for LoongArch.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1 files changed, 41 insertions, 2 deletions

diff --git a/arch/loongarch/kernel/topology.c b/arch/loongarch/kernel/topology.c
index 3b2cbb95875b..ab1a75c0b5a6 100644
--- a/arch/loongarch/kernel/topology.c
+++ b/arch/loongarch/kernel/topology.c
@@ -1,13 +1,52 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/cpu.h>
+#include <linux/cpumask.h>
 #include <linux/init.h>
+#include <linux/node.h>
+#include <linux/nodemask.h>
 #include <linux/percpu.h>
 
-static struct cpu cpu_device;
+static DEFINE_PER_CPU(struct cpu, cpu_devices);
+
+#ifdef CONFIG_HOTPLUG_CPU
+int arch_register_cpu(int cpu)
+{
+	int ret;
+	struct cpu *c = &per_cpu(cpu_devices, cpu);
+
+	c->hotpluggable = 1;
+	ret = register_cpu(c, cpu);
+	if (ret < 0)
+		pr_warn("register_cpu %d failed (%d)\n", cpu, ret);
+
+	return ret;
+}
+EXPORT_SYMBOL(arch_register_cpu);
+
+void arch_unregister_cpu(int cpu)
+{
+	struct cpu *c = &per_cpu(cpu_devices, cpu);
+
+	c->hotpluggable = 0;
+	unregister_cpu(c);
+}
+EXPORT_SYMBOL(arch_unregister_cpu);
+#endif
 
 static int __init topology_init(void)
 {
-	return register_cpu(&cpu_device, 0);
+	int i, ret;
+
+	for_each_present_cpu(i) {
+		struct cpu *c = &per_cpu(cpu_devices, i);
+
+		c->hotpluggable = !!i;
+		ret = register_cpu(c, i);
+		if (ret < 0)
+			pr_warn("topology_init: register_cpu %d failed (%d)\n", i, ret);
+	}
+
+	return 0;
 }
 
 subsys_initcall(topology_init);