MIPS: Add arch generic CPU hotplug

Each platform has to add support for CPU hotplugging itself by providing
suitable definitions for the cpu_disable and cpu_die of the smp_ops
methods and setting SYS_SUPPORTS_HOTPLUG_CPU.  A platform should only set
SYS_SUPPORTS_HOTPLUG_CPU once all it's smp_ops definitions have the
necessary changes.  This patch contains the changes to the dummy smp_ops
definition for uni-processor systems.

Parts of the code contributed by Cavium Inc.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/mips/kernel/smp-up.c b/arch/mips/kernel/smp-up.c
index 878e3733bbb2..2508d55d68fd 100644
--- a/arch/mips/kernel/smp-up.c
+++ b/arch/mips/kernel/smp-up.c
@@ -55,6 +55,18 @@ static void __init up_prepare_cpus(unsigned int max_cpus)
 {
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+static int up_cpu_disable(void)
+{
+        return -ENOSYS;
+}
+
+static void up_cpu_die(unsigned int cpu)
+{
+        BUG();
+}
+#endif
+
 struct plat_smp_ops up_smp_ops = {
         .send_ipi_single        = up_send_ipi_single,
         .send_ipi_mask          = up_send_ipi_mask,
@@ -64,4 +76,8 @@ struct plat_smp_ops up_smp_ops = {
         .boot_secondary         = up_boot_secondary,
         .smp_setup              = up_smp_setup,
         .prepare_cpus           = up_prepare_cpus,
+#ifdef CONFIG_HOTPLUG_CPU
+        .cpu_disable            = up_cpu_disable,
+        .cpu_die                = up_cpu_die,
+#endif
 };