1 files changed, 48 insertions, 0 deletions

diff --git a/arch/arm/mach-mvebu/platsmp.c b/arch/arm/mach-mvebu/platsmp.c
index 88b976b31719..b6fa9f0c98b8 100644
--- a/arch/arm/mach-mvebu/platsmp.c
+++ b/arch/arm/mach-mvebu/platsmp.c
@@ -78,6 +78,17 @@ static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle)
 
         hw_cpu = cpu_logical_map(cpu);
         mvebu_pmsu_set_cpu_boot_addr(hw_cpu, armada_xp_secondary_startup);
+
+        /*
+         * This is needed to wake up CPUs in the offline state after
+         * using CPU hotplug.
+         */
+        arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
+        /*
+         * This is needed to take secondary CPUs out of reset on the
+         * initial boot.
+         */
         ret = mvebu_cpu_reset_deassert(hw_cpu);
         if (ret) {
                 pr_warn("unable to boot CPU: %d\n", ret);
@@ -87,6 +98,19 @@ static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle)
         return 0;
 }
 
+/*
+ * When a CPU is brought back online, either through CPU hotplug, or
+ * because of the boot of a kexec'ed kernel, the PMSU configuration
+ * for this CPU might be in the deep idle state, preventing this CPU
+ * from receiving interrupts. Here, we therefore take out the current
+ * CPU from this state, which was entered by armada_xp_cpu_die()
+ * below.
+ */
+static void armada_xp_secondary_init(unsigned int cpu)
+{
+        armada_370_xp_pmsu_idle_exit();
+}
+
 static void __init armada_xp_smp_init_cpus(void)
 {
         unsigned int ncores = num_possible_cpus();
@@ -122,12 +146,36 @@ static void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus)
                 panic("The address for the BootROM is incorrect");
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+static void armada_xp_cpu_die(unsigned int cpu)
+{
+        /*
+         * CPU hotplug is implemented by putting offline CPUs into the
+         * deep idle sleep state.
+         */
+        armada_370_xp_pmsu_idle_enter(true);
+}
+
+/*
+ * We need a dummy function, so that platform_can_cpu_hotplug() knows
+ * we support CPU hotplug. However, the function does not need to do
+ * anything, because CPUs going offline can enter the deep idle state
+ * by themselves, without any help from a still alive CPU.
+ */
+static int armada_xp_cpu_kill(unsigned int cpu)
+{
+        return 1;
+}
+#endif
+
 struct smp_operations armada_xp_smp_ops __initdata = {
         .smp_init_cpus          = armada_xp_smp_init_cpus,
         .smp_prepare_cpus       = armada_xp_smp_prepare_cpus,
         .smp_boot_secondary     = armada_xp_boot_secondary,
+        .smp_secondary_init     = armada_xp_secondary_init,
 #ifdef CONFIG_HOTPLUG_CPU
         .cpu_die                = armada_xp_cpu_die,
+        .cpu_kill               = armada_xp_cpu_kill,
 #endif
 };