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/hardware/cache-l2x0.h>
  41 #include <asm/exception.h>
  42 #include <asm/mach/arch.h>
  43 #include <asm/mach/irq.h>
  44 #include <asm/mach/time.h>
  45
  46 unsigned long irq_err_count;
  47
  48 int arch_show_interrupts(struct seq_file *p, int prec)
  49 {
  50 #ifdef CONFIG_FIQ
  51         show_fiq_list(p, prec);
  52 #endif
  53 #ifdef CONFIG_SMP
  54         show_ipi_list(p, prec);
  55 #endif
  56         seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
  57         return 0;
  58 }
  59
  60 /*
  61  * handle_IRQ handles all hardware IRQ's.  Decoded IRQs should
  62  * not come via this function.  Instead, they should provide their
  63  * own 'handler'.  Used by platform code implementing C-based 1st
  64  * level decoding.
  65  */
  66 void handle_IRQ(unsigned int irq, struct pt_regs *regs)
  67 {
  68         struct pt_regs *old_regs = set_irq_regs(regs);
  69
  70         irq_enter();
  71
  72         /*
  73          * Some hardware gives randomly wrong interrupts.  Rather
  74          * than crashing, do something sensible.
  75          */
  76         if (unlikely(irq >= nr_irqs)) {
  77                 if (printk_ratelimit())
  78                         printk(KERN_WARNING "Bad IRQ%u\n", irq);
  79                 ack_bad_irq(irq);
  80         } else {
  81                 generic_handle_irq(irq);
  82         }
  83
  84         irq_exit();
  85         set_irq_regs(old_regs);
  86 }
  87
  88 /*
  89  * asm_do_IRQ is the interface to be used from assembly code.
  90  */
  91 asmlinkage void __exception_irq_entry
  92 asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
  93 {
  94         handle_IRQ(irq, regs);
  95 }
  96
  97 void set_irq_flags(unsigned int irq, unsigned int iflags)
  98 {
  99         unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 100
 101         if (irq >= nr_irqs) {
 102                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 103                 return;
 104         }
 105
 106         if (iflags & IRQF_VALID)
 107                 clr |= IRQ_NOREQUEST;
 108         if (iflags & IRQF_PROBE)
 109                 clr |= IRQ_NOPROBE;
 110         if (!(iflags & IRQF_NOAUTOEN))
 111                 clr |= IRQ_NOAUTOEN;
 112         /* Order is clear bits in "clr" then set bits in "set" */
 113         irq_modify_status(irq, clr, set & ~clr);
 114 }
 115 EXPORT_SYMBOL_GPL(set_irq_flags);
 116
 117 void __init init_IRQ(void)
 118 {
 119         int ret;
 120
 121         if (IS_ENABLED(CONFIG_OF) && !machine_desc->init_irq)
 122                 irqchip_init();
 123         else
 124                 machine_desc->init_irq();
 125
 126         if (IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_CACHE_L2X0) &&
 127             (machine_desc->l2c_aux_mask || machine_desc->l2c_aux_val)) {
 128                 outer_cache.write_sec = machine_desc->l2c_write_sec;
 129                 ret = l2x0_of_init(machine_desc->l2c_aux_val,
 130                                    machine_desc->l2c_aux_mask);
 131                 if (ret)
 132                         pr_err("L2C: failed to init: %d\n", ret);
 133         }
 134 }
 135
 136 #ifdef CONFIG_MULTI_IRQ_HANDLER
 137 void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 138 {
 139         if (handle_arch_irq)
 140                 return;
 141
 142         handle_arch_irq = handle_irq;
 143 }
 144 #endif
 145
 146 #ifdef CONFIG_SPARSE_IRQ
 147 int __init arch_probe_nr_irqs(void)
 148 {
 149         nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
 150         return nr_irqs;
 151 }
 152 #endif
 153
 154 #ifdef CONFIG_HOTPLUG_CPU
 155
 156 static bool migrate_one_irq(struct irq_desc *desc)
 157 {
 158         struct irq_data *d = irq_desc_get_irq_data(desc);
 159         const struct cpumask *affinity = d->affinity;
 160         struct irq_chip *c;
 161         bool ret = false;
 162
 163         /*
 164          * If this is a per-CPU interrupt, or the affinity does not
 165          * include this CPU, then we have nothing to do.
 166          */
 167         if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
 168                 return false;
 169
 170         if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 171                 affinity = cpu_online_mask;
 172                 ret = true;
 173         }
 174
 175         c = irq_data_get_irq_chip(d);
 176         if (!c->irq_set_affinity)
 177                 pr_debug("IRQ%u: unable to set affinity\n", d->irq);
 178         else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret)
 179                 cpumask_copy(d->affinity, affinity);
 180
 181         return ret;
 182 }
 183
 184 /*
 185  * The current CPU has been marked offline.  Migrate IRQs off this CPU.
 186  * If the affinity settings do not allow other CPUs, force them onto any
 187  * available CPU.
 188  *
 189  * Note: we must iterate over all IRQs, whether they have an attached
 190  * action structure or not, as we need to get chained interrupts too.
 191  */
 192 void migrate_irqs(void)
 193 {
 194         unsigned int i;
 195         struct irq_desc *desc;
 196         unsigned long flags;
 197
 198         local_irq_save(flags);
 199
 200         for_each_irq_desc(i, desc) {
 201                 bool affinity_broken;
 202
 203                 raw_spin_lock(&desc->lock);
 204                 affinity_broken = migrate_one_irq(desc);
 205                 raw_spin_unlock(&desc->lock);
 206
 207                 if (affinity_broken && printk_ratelimit())
 208                         pr_warning("IRQ%u no longer affine to CPU%u\n", i,
 209                                 smp_processor_id());
 210         }
 211
 212         local_irq_restore(flags);
 213 }
 214 #endif /* CONFIG_HOTPLUG_CPU */