[PATCH v4 16/19] MIPS: Add generic SMP IPI support

Qais Yousef
2015-12-08T13:22:47Z

Use the new generic IPI layer to provide generic SMP IPI support if the irqchip
supports it.

Signed-off-by: Qais Yousef <qais.yousef@imgtec.com>
---
arch/mips/kernel/smp.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 136 insertions(+)

diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index bd4385a8e6e8..c012e1903f6b 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -33,12 +33,16 @@
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/ftrace.h>
+#include <linux/irqdomain.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>

#include <linux/atomic.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/idle.h>
#include <asm/r4k-timer.h>
+#include <asm/mips-cpc.h>
#include <asm/mmu_context.h>
#include <asm/time.h>
#include <asm/setup.h>
@@ -79,6 +83,11 @@ static cpumask_t cpu_core_setup_map;

cpumask_t cpu_coherent_mask;

+#ifdef CONFIG_GENERIC_IRQ_IPI
+static struct irq_desc *call_desc;
+static struct irq_desc *sched_desc;
+#endif
+
static inline void set_cpu_sibling_map(int cpu)
{
int i;
@@ -145,6 +154,133 @@ void register_smp_ops(struct plat_smp_ops *ops)
mp_ops = ops;
}

+#ifdef CONFIG_GENERIC_IRQ_IPI
+void mips_smp_send_ipi_single(int cpu, unsigned int action)
+{
+ mips_smp_send_ipi_mask(cpumask_of(cpu), action);
+}
+
+void mips_smp_send_ipi_mask(const struct cpumask *mask, unsigned int action)
+{
+ unsigned long flags;
+ unsigned int core;
+ int cpu;
+
+ local_irq_save(flags);
+
+ switch (action) {
+ case SMP_CALL_FUNCTION:
+ __ipi_send_mask(call_desc, mask);
+ break;
+
+ case SMP_RESCHEDULE_YOURSELF:
+ __ipi_send_mask(sched_desc, mask);
+ break;
+
+ default:
+ BUG();
+ }
+
+ if (mips_cpc_present()) {
+ for_each_cpu(cpu, mask) {
+ core = cpu_data[cpu].core;
+
+ if (core == current_cpu_data.core)
+ continue;
+
+ while (!cpumask_test_cpu(cpu, &cpu_coherent_mask)) {
+ mips_cpc_lock_other(core);
+ write_cpc_co_cmd(CPC_Cx_CMD_PWRUP);
+ mips_cpc_unlock_other();
+ }
+ }
+ }
+
+ local_irq_restore(flags);
+}
+
+
+static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id)
+{
+ scheduler_ipi();
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t ipi_call_interrupt(int irq, void *dev_id)
+{
+ generic_smp_call_function_interrupt();
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction irq_resched = {
+ .handler = ipi_resched_interrupt,
+ .flags = IRQF_PERCPU,
+ .name = "IPI resched"
+};
+
+static struct irqaction irq_call = {
+ .handler = ipi_call_interrupt,
+ .flags = IRQF_PERCPU,
+ .name = "IPI call"
+};
+
+static __init void smp_ipi_init_one(unsigned int virq,
+ struct irqaction *action)
+{
+ int ret;
+
+ irq_set_handler(virq, handle_percpu_irq);
+ ret = setup_irq(virq, action);
+ BUG_ON(ret);
+}
+
+static int __init mips_smp_ipi_init(void)
+{
+ unsigned int call_virq, sched_virq;
+ 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);
+
+ call_virq = irq_reserve_ipi(ipidomain, cpu_possible_mask);
+ BUG_ON(!call_virq);
+
+ sched_virq = irq_reserve_ipi(ipidomain, cpu_possible_mask);
+ BUG_ON(!sched_virq);
+
+ if (irq_domain_is_ipi_per_cpu(ipidomain)) {
+ int cpu;
+
+ for_each_cpu(cpu, cpu_possible_mask) {
+ smp_ipi_init_one(call_virq + cpu, &irq_call);
+ smp_ipi_init_one(sched_virq + cpu, &irq_resched);
+ }
+ } else {
+ smp_ipi_init_one(call_virq, &irq_call);
+ smp_ipi_init_one(sched_virq, &irq_resched);
+ }
+
+ call_desc = irq_to_desc(call_virq);
+ sched_desc = irq_to_desc(sched_virq);
+
+ return 0;
+}
+early_initcall(mips_smp_ipi_init);
+#endif
+
/*
* First C code run on the secondary CPUs after being started up by
* the master.
--
2.1.0