From c512c6ba7ac41b8bc196f17a85ee52099a109146 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 11 Dec 2015 19:31:23 +0530 Subject: [PATCH] ARC: intc: Document arc_request_percpu_irq() better Signed-off-by: Vineet Gupta --- arch/arc/kernel/irq.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/arc/kernel/irq.c b/arch/arc/kernel/irq.c index d736678d2724..b1f75937f0e1 100644 --- a/arch/arc/kernel/irq.c +++ b/arch/arc/kernel/irq.c @@ -51,6 +51,18 @@ void arch_do_IRQ(unsigned int irq, struct pt_regs *regs) set_irq_regs(old_regs); } +/* + * API called for requesting percpu interrupts - called by each CPU + * - For boot CPU, actually request the IRQ with genirq core + enables + * - For subsequent callers only enable called locally + * + * Relies on being called by boot cpu first (i.e. request called ahead) of + * any enable as expected by genirq. Hence Suitable only for TIMER, IPI + * which are guaranteed to be setup on boot core first. + * Late probed peripherals such as perf can't use this as there no guarantee + * of being called on boot CPU first. + */ + void arc_request_percpu_irq(int irq, int cpu, irqreturn_t (*isr)(int irq, void *dev), const char *irq_nm, -- 2.20.1