2 files changed, 67 insertions, 8 deletions

diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h
index 8bc6c70a4030..060f23ff1817 100644
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -85,6 +85,20 @@ static inline void __cpu_die(unsigned int cpu)
 extern void play_dead(void);
 #endif
 
+/*
+ * This function will set up the necessary IPIs for Linux to communicate
+ * with the CPUs in mask.
+ * Return 0 on success.
+ */
+int mips_smp_ipi_allocate(const struct cpumask *mask);
+
+/*
+ * This function will free up IPIs allocated with mips_smp_ipi_allocate to the
+ * CPUs in mask, which must be a subset of the IPIs that have been configured.
+ * Return 0 on success.
+ */
+int mips_smp_ipi_free(const struct cpumask *mask);
+
 static inline void arch_send_call_function_single_ipi(int cpu)
 {
         extern struct plat_smp_ops *mp_ops;     /* private */
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index cb02df215365..0e131c9c39f6 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -231,7 +231,7 @@ static struct irqaction irq_call = {
         .name           = "IPI call"
 };
 
-static __init void smp_ipi_init_one(unsigned int virq,
+static void smp_ipi_init_one(unsigned int virq,
                                     struct irqaction *action)
 {
         int ret;
@@ -241,9 +241,11 @@ static __init void smp_ipi_init_one(unsigned int virq,
         BUG_ON(ret);
 }
 
-static int __init mips_smp_ipi_init(void)
+static unsigned int call_virq, sched_virq;
+
+int mips_smp_ipi_allocate(const struct cpumask *mask)
 {
-        unsigned int call_virq, sched_virq;
+        int virq;
         struct irq_domain *ipidomain;
         struct device_node *node;
 
@@ -270,16 +272,20 @@ static int __init mips_smp_ipi_init(void)
         if (!ipidomain)
                 return 0;
 
-        call_virq = irq_reserve_ipi(ipidomain, cpu_possible_mask);
-        BUG_ON(!call_virq);
+        virq = irq_reserve_ipi(ipidomain, mask);
+        BUG_ON(!virq);
+        if (!call_virq)
+                call_virq = virq;
 
-        sched_virq = irq_reserve_ipi(ipidomain, cpu_possible_mask);
-        BUG_ON(!sched_virq);
+        virq = irq_reserve_ipi(ipidomain, mask);
+        BUG_ON(!virq);
+        if (!sched_virq)
+                sched_virq = virq;
 
         if (irq_domain_is_ipi_per_cpu(ipidomain)) {
                 int cpu;
 
-                for_each_cpu(cpu, cpu_possible_mask) {
+                for_each_cpu(cpu, mask) {
                         smp_ipi_init_one(call_virq + cpu, &irq_call);
                         smp_ipi_init_one(sched_virq + cpu, &irq_resched);
                 }
@@ -288,6 +294,45 @@ static int __init mips_smp_ipi_init(void)
                 smp_ipi_init_one(sched_virq, &irq_resched);
         }
 
+        return 0;
+}
+
+int mips_smp_ipi_free(const struct cpumask *mask)
+{
+        struct irq_domain *ipidomain;
+        struct device_node *node;
+
+        node = of_irq_find_parent(of_root);
+        ipidomain = irq_find_matching_host(node, DOMAIN_BUS_IPI);
+
+        /*
+         * Some platforms have half DT setup. So if we found irq node but
+         * didn't find an ipidomain, try to search for one that is not in the
+         * DT.
+         */
+        if (node && !ipidomain)
+                ipidomain = irq_find_matching_host(NULL, DOMAIN_BUS_IPI);
+
+        BUG_ON(!ipidomain);
+
+        if (irq_domain_is_ipi_per_cpu(ipidomain)) {
+                int cpu;
+
+                for_each_cpu(cpu, mask) {
+                        remove_irq(call_virq + cpu, &irq_call);
+                        remove_irq(sched_virq + cpu, &irq_resched);
+                }
+        }
+        irq_destroy_ipi(call_virq, mask);
+        irq_destroy_ipi(sched_virq, mask);
+        return 0;
+}
+
+
+static int __init mips_smp_ipi_init(void)
+{
+        mips_smp_ipi_allocate(cpu_possible_mask);
+
         call_desc = irq_to_desc(call_virq);
         sched_desc = irq_to_desc(sched_virq);