X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=arch%2Farm%2Fmach-mvebu%2Fplatsmp.c;h=f278acebeaebf12c2a510a4f9e9404763c4a2acc;hb=ba3ec5780bba27819bbc4f669e6c77418a00f14b;hp=4880b0f7036243257973fd92fb3bb5322d17e470;hpb=ee2d8ea1e9bb27989f4f157520500dd6c4d45347;p=firefly-linux-kernel-4.4.55.git

diff --git a/arch/arm/mach-mvebu/platsmp.c b/arch/arm/mach-mvebu/platsmp.c
index 4880b0f70362..f278acebeaeb 100644
--- a/arch/arm/mach-mvebu/platsmp.c
+++ b/arch/arm/mach-mvebu/platsmp.c
@@ -79,6 +79,17 @@ 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);
@@ -88,6 +99,19 @@ 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();
@@ -123,12 +147,36 @@ 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
 };