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/random.h> 30 #include <linux/smp.h> 31 #include <linux/init.h> 32 #include <linux/seq_file.h> 33 #include <linux/errno.h> 34 #include <linux/list.h> 35 #include <linux/kallsyms.h> 36 #include <linux/proc_fs.h> 37 38 #include <asm/exception.h> 39 #include <asm/mach/arch.h> 40 #include <asm/mach/irq.h> 41 #include <asm/mach/time.h> 42 43 unsigned long irq_err_count; 44 45 int arch_show_interrupts(struct seq_file *p, int prec) 46 { 47 #ifdef CONFIG_FIQ 48 show_fiq_list(p, prec); 49 #endif 50 #ifdef CONFIG_SMP 51 show_ipi_list(p, prec); 52 #endif 53 seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count); 54 return 0; 55 } 56 57 /* 58 * handle_IRQ handles all hardware IRQ's. Decoded IRQs should 59 * not come via this function. Instead, they should provide their 60 * own 'handler'. Used by platform code implementing C-based 1st 61 * level decoding. 62 */ 63 void handle_IRQ(unsigned int irq, struct pt_regs *regs) 64 { 65 struct pt_regs *old_regs = set_irq_regs(regs); 66 67 irq_enter(); 68 69 /* 70 * Some hardware gives randomly wrong interrupts. Rather 71 * than crashing, do something sensible. 72 */ 73 if (unlikely(irq >= nr_irqs)) { 74 if (printk_ratelimit()) 75 printk(KERN_WARNING "Bad IRQ%u\n", irq); 76 ack_bad_irq(irq); 77 } else { 78 generic_handle_irq(irq); 79 } 80 81 irq_exit(); 82 set_irq_regs(old_regs); 83 } 84 85 /* 86 * asm_do_IRQ is the interface to be used from assembly code. 87 */ 88 asmlinkage void __exception_irq_entry 89 asm_do_IRQ(unsigned int irq, struct pt_regs *regs) 90 { 91 handle_IRQ(irq, regs); 92 } 93 94 void set_irq_flags(unsigned int irq, unsigned int iflags) 95 { 96 unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN; 97 98 if (irq >= nr_irqs) { 99 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq); 100 return; 101 } 102 103 if (iflags & IRQF_VALID) 104 clr |= IRQ_NOREQUEST; 105 if (iflags & IRQF_PROBE) 106 clr |= IRQ_NOPROBE; 107 if (!(iflags & IRQF_NOAUTOEN)) 108 clr |= IRQ_NOAUTOEN; 109 /* Order is clear bits in "clr" then set bits in "set" */ 110 irq_modify_status(irq, clr, set & ~clr); 111 } 112 113 void __init init_IRQ(void) 114 { 115 machine_desc->init_irq(); 116 } 117 118 #ifdef CONFIG_SPARSE_IRQ 119 int __init arch_probe_nr_irqs(void) 120 { 121 nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS; 122 return nr_irqs; 123 } 124 #endif 125 126 #ifdef CONFIG_HOTPLUG_CPU 127 128 static bool migrate_one_irq(struct irq_desc *desc) 129 { 130 struct irq_data *d = irq_desc_get_irq_data(desc); 131 const struct cpumask *affinity = d->affinity; 132 struct irq_chip *c; 133 bool ret = false; 134 135 /* 136 * If this is a per-CPU interrupt, or the affinity does not 137 * include this CPU, then we have nothing to do. 138 */ 139 if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity)) 140 return false; 141 142 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) { 143 affinity = cpu_online_mask; 144 ret = true; 145 } 146 147 c = irq_data_get_irq_chip(d); 148 if (!c->irq_set_affinity) 149 pr_debug("IRQ%u: unable to set affinity\n", d->irq); 150 else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret) 151 cpumask_copy(d->affinity, affinity); 152 153 return ret; 154 } 155 156 /* 157 * The current CPU has been marked offline. Migrate IRQs off this CPU. 158 * If the affinity settings do not allow other CPUs, force them onto any 159 * available CPU. 160 * 161 * Note: we must iterate over all IRQs, whether they have an attached 162 * action structure or not, as we need to get chained interrupts too. 163 */ 164 void migrate_irqs(void) 165 { 166 unsigned int i; 167 struct irq_desc *desc; 168 unsigned long flags; 169 170 local_irq_save(flags); 171 172 for_each_irq_desc(i, desc) { 173 bool affinity_broken; 174 175 raw_spin_lock(&desc->lock); 176 affinity_broken = migrate_one_irq(desc); 177 raw_spin_unlock(&desc->lock); 178 179 if (affinity_broken && printk_ratelimit()) 180 pr_warning("IRQ%u no longer affine to CPU%u\n", i, 181 smp_processor_id()); 182 } 183 184 local_irq_restore(flags); 185 } 186 #endif /* CONFIG_HOTPLUG_CPU */ 187