arch/arm/kernel/irq.c

   1 /*
   2  *  linux/arch/arm/kernel/irq.c
   3  *
   4  *  Copyright (C) 1992 Linus Torvalds
   5  *  Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
   6  *
   7  *  Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
   8  *  Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
   9  *  Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  *  This file contains the code used by various IRQ handling routines:
  16  *  asking for different IRQ's should be done through these routines
  17  *  instead of just grabbing them. Thus setups with different IRQ numbers
  18  *  shouldn't result in any weird surprises, and installing new handlers
  19  *  should be easier.
  20  *
  21  *  IRQ's are in fact implemented a bit like signal handlers for the kernel.
  22  *  Naturally it's not a 1:1 relation, but there are similarities.
  23  */
  24 #include <linux/kernel_stat.h>
  25 #include <linux/signal.h>
  26 #include <linux/ioport.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/irq.h>
  29 #include <linux/irqchip.h>
  30 #include <linux/random.h>
  31 #include <linux/smp.h>
  32 #include <linux/init.h>
  33 #include <linux/seq_file.h>
  34 #include <linux/errno.h>
  35 #include <linux/list.h>
  36 #include <linux/kallsyms.h>
  37 #include <linux/proc_fs.h>
  38 #include <linux/export.h>
  39
  40 #include <asm/exception.h>
  41 #include <asm/mach/arch.h>
  42 #include <asm/mach/irq.h>
  43 #include <asm/mach/time.h>
  44
  45 unsigned long irq_err_count;
  46
  47 int arch_show_interrupts(struct seq_file *p, int prec)
  48 {
  49 #ifdef CONFIG_FIQ
  50         show_fiq_list(p, prec);
  51 #endif
  52 #ifdef CONFIG_SMP
  53         show_ipi_list(p, prec);
  54 #endif
  55         seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
  56         return 0;
  57 }
  58
  59 /*
  60  * handle_IRQ handles all hardware IRQ's.  Decoded IRQs should
  61  * not come via this function.  Instead, they should provide their
  62  * own 'handler'.  Used by platform code implementing C-based 1st
  63  * level decoding.
  64  */
  65 void handle_IRQ(unsigned int irq, struct pt_regs *regs)
  66 {
  67         struct pt_regs *old_regs = set_irq_regs(regs);
  68
  69         irq_enter();
  70
  71         /*
  72          * Some hardware gives randomly wrong interrupts.  Rather
  73          * than crashing, do something sensible.
  74          */
  75         if (unlikely(irq >= nr_irqs)) {
  76                 if (printk_ratelimit())
  77                         printk(KERN_WARNING "Bad IRQ%u\n", irq);
  78                 ack_bad_irq(irq);
  79         } else {
  80                 generic_handle_irq(irq);
  81         }
  82
  83         irq_exit();
  84         set_irq_regs(old_regs);
  85 }
  86
  87 /*
  88  * asm_do_IRQ is the interface to be used from assembly code.
  89  */
  90 asmlinkage void __exception_irq_entry
  91 asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
  92 {
  93         handle_IRQ(irq, regs);
  94 }
  95
  96 void set_irq_flags(unsigned int irq, unsigned int iflags)
  97 {
  98         unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
  99
 100         if (irq >= nr_irqs) {
 101                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 102                 return;
 103         }
 104
 105         if (iflags & IRQF_VALID)
 106                 clr |= IRQ_NOREQUEST;
 107         if (iflags & IRQF_PROBE)
 108                 clr |= IRQ_NOPROBE;
 109         if (!(iflags & IRQF_NOAUTOEN))
 110                 clr |= IRQ_NOAUTOEN;
 111         /* Order is clear bits in "clr" then set bits in "set" */
 112         irq_modify_status(irq, clr, set & ~clr);
 113 }
 114 EXPORT_SYMBOL_GPL(set_irq_flags);
 115
 116 void __init init_IRQ(void)
 117 {
 118         if (IS_ENABLED(CONFIG_OF) && !machine_desc->init_irq)
 119                 irqchip_init();
 120         else
 121                 machine_desc->init_irq();
 122 }
 123
 124 #ifdef CONFIG_MULTI_IRQ_HANDLER
 125 void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 126 {
 127         if (handle_arch_irq)
 128                 return;
 129
 130         handle_arch_irq = handle_irq;
 131 }
 132 #endif
 133
 134 #ifdef CONFIG_SPARSE_IRQ
 135 int __init arch_probe_nr_irqs(void)
 136 {
 137         nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
 138         return nr_irqs;
 139 }
 140 #endif
 141
 142 #ifdef CONFIG_HOTPLUG_CPU
 143
 144 static bool migrate_one_irq(struct irq_desc *desc)
 145 {
 146         struct irq_data *d = irq_desc_get_irq_data(desc);
 147         const struct cpumask *affinity = d->affinity;
 148         struct irq_chip *c;
 149         bool ret = false;
 150
 151         /*
 152          * If this is a per-CPU interrupt, or the affinity does not
 153          * include this CPU, then we have nothing to do.
 154          */
 155         if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
 156                 return false;
 157
 158         if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 159                 affinity = cpu_online_mask;
 160                 ret = true;
 161         }
 162
 163         c = irq_data_get_irq_chip(d);
 164         if (!c->irq_set_affinity)
 165                 pr_debug("IRQ%u: unable to set affinity\n", d->irq);
 166         else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret)
 167                 cpumask_copy(d->affinity, affinity);
 168
 169         return ret;
 170 }
 171
 172 /*
 173  * The current CPU has been marked offline.  Migrate IRQs off this CPU.
 174  * If the affinity settings do not allow other CPUs, force them onto any
 175  * available CPU.
 176  *
 177  * Note: we must iterate over all IRQs, whether they have an attached
 178  * action structure or not, as we need to get chained interrupts too.
 179  */
 180 void migrate_irqs(void)
 181 {
 182         unsigned int i;
 183         struct irq_desc *desc;
 184         unsigned long flags;
 185
 186         local_irq_save(flags);
 187
 188         for_each_irq_desc(i, desc) {
 189                 bool affinity_broken;
 190
 191                 raw_spin_lock(&desc->lock);
 192                 affinity_broken = migrate_one_irq(desc);
 193                 raw_spin_unlock(&desc->lock);
 194
 195                 if (affinity_broken && printk_ratelimit())
 196                         pr_warning("IRQ%u no longer affine to CPU%u\n", i,
 197                                 smp_processor_id());
 198         }
 199
 200         local_irq_restore(flags);
 201 }
 202 #endif /* CONFIG_HOTPLUG_CPU */