arch/arc/kernel/irq.c

   1 /*
   2  * Copyright (C) 2011-12 Synopsys, Inc. (www.synopsys.com)
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include <linux/interrupt.h>
  11 #include <linux/irqchip.h>
  12 #include <asm/mach_desc.h>
  13 #include <asm/smp.h>
  14
  15 /*
  16  * Late Interrupt system init called from start_kernel for Boot CPU only
  17  *
  18  * Since slab must already be initialized, platforms can start doing any
  19  * needed request_irq( )s
  20  */
  21 void __init init_IRQ(void)
  22 {
  23         /*
  24          * process the entire interrupt tree in one go
  25          * Any external intc will be setup provided DT chains them
  26          * properly
  27          */
  28         irqchip_init();
  29
  30 #ifdef CONFIG_SMP
  31         /* a SMP H/w block could do IPI IRQ request here */
  32         if (plat_smp_ops.init_per_cpu)
  33                 plat_smp_ops.init_per_cpu(smp_processor_id());
  34
  35         if (machine_desc->init_per_cpu)
  36                 machine_desc->init_per_cpu(smp_processor_id());
  37 #endif
  38 }
  39
  40 /*
  41  * "C" Entry point for any ARC ISR, called from low level vector handler
  42  * @irq is the vector number read from ICAUSE reg of on-chip intc
  43  */
  44 void arch_do_IRQ(unsigned int irq, struct pt_regs *regs)
  45 {
  46         struct pt_regs *old_regs = set_irq_regs(regs);
  47
  48         irq_enter();
  49         generic_handle_irq(irq);
  50         irq_exit();
  51         set_irq_regs(old_regs);
  52 }
  53
  54 /*
  55  * API called for requesting percpu interrupts - called by each CPU
  56  *  - For boot CPU, actually request the IRQ with genirq core + enables
  57  *  - For subsequent callers only enable called locally
  58  *
  59  * Relies on being called by boot cpu first (i.e. request called ahead) of
  60  * any enable as expected by genirq. Hence Suitable only for TIMER, IPI
  61  * which are guaranteed to be setup on boot core first.
  62  * Late probed peripherals such as perf can't use this as there no guarantee
  63  * of being called on boot CPU first.
  64  */
  65
  66 void arc_request_percpu_irq(int irq, int cpu,
  67                             irqreturn_t (*isr)(int irq, void *dev),
  68                             const char *irq_nm,
  69                             void *percpu_dev)
  70 {
  71         /* Boot cpu calls request, all call enable */
  72         if (!cpu) {
  73                 int rc;
  74
  75 #ifdef CONFIG_ISA_ARCOMPACT
  76                 /*
  77                  * A subsequent request_percpu_irq() fails if percpu_devid is
  78                  * not set. That in turns sets NOAUTOEN, meaning each core needs
  79                  * to call enable_percpu_irq()
  80                  *
  81                  * For ARCv2, this is done in irq map function since we know
  82                  * which irqs are strictly per cpu
  83                  */
  84                 irq_set_percpu_devid(irq);
  85 #endif
  86
  87                 rc = request_percpu_irq(irq, isr, irq_nm, percpu_dev);
  88                 if (rc)
  89                         panic("Percpu IRQ request failed for %d\n", irq);
  90         }
  91
  92         enable_percpu_irq(irq, 0);
  93 }