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/module.h> 26 #include <linux/signal.h> 27 #include <linux/ioport.h> 28 #include <linux/interrupt.h> 29 #include <linux/irq.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/ftrace.h> 39 40 #include <asm/system.h> 41 #include <asm/mach/arch.h> 42 #include <asm/mach/irq.h> 43 #include <asm/mach/time.h> 44 45 /* 46 * No architecture-specific irq_finish function defined in arm/arch/irqs.h. 47 */ 48 #ifndef irq_finish 49 #define irq_finish(irq) do { } while (0) 50 #endif 51 52 unsigned long irq_err_count; 53 54 int arch_show_interrupts(struct seq_file *p, int prec) 55 { 56 #ifdef CONFIG_FIQ 57 show_fiq_list(p, prec); 58 #endif 59 #ifdef CONFIG_SMP 60 show_ipi_list(p, prec); 61 #endif 62 #ifdef CONFIG_LOCAL_TIMERS 63 show_local_irqs(p, prec); 64 #endif 65 seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count); 66 return 0; 67 } 68 69 /* 70 * handle_IRQ handles all hardware IRQ's. Decoded IRQs should 71 * not come via this function. Instead, they should provide their 72 * own 'handler'. Used by platform code implementing C-based 1st 73 * level decoding. 74 */ 75 void handle_IRQ(unsigned int irq, struct pt_regs *regs) 76 { 77 struct pt_regs *old_regs = set_irq_regs(regs); 78 79 irq_enter(); 80 81 /* 82 * Some hardware gives randomly wrong interrupts. Rather 83 * than crashing, do something sensible. 84 */ 85 if (unlikely(irq >= nr_irqs)) { 86 if (printk_ratelimit()) 87 printk(KERN_WARNING "Bad IRQ%u\n", irq); 88 ack_bad_irq(irq); 89 } else { 90 generic_handle_irq(irq); 91 } 92 93 /* AT91 specific workaround */ 94 irq_finish(irq); 95 96 irq_exit(); 97 set_irq_regs(old_regs); 98 } 99 100 /* 101 * asm_do_IRQ is the interface to be used from assembly code. 102 */ 103 asmlinkage void __exception_irq_entry 104 asm_do_IRQ(unsigned int irq, struct pt_regs *regs) 105 { 106 handle_IRQ(irq, regs); 107 } 108 109 void set_irq_flags(unsigned int irq, unsigned int iflags) 110 { 111 unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN; 112 113 if (irq >= nr_irqs) { 114 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq); 115 return; 116 } 117 118 if (iflags & IRQF_VALID) 119 clr |= IRQ_NOREQUEST; 120 if (iflags & IRQF_PROBE) 121 clr |= IRQ_NOPROBE; 122 if (!(iflags & IRQF_NOAUTOEN)) 123 clr |= IRQ_NOAUTOEN; 124 /* Order is clear bits in "clr" then set bits in "set" */ 125 irq_modify_status(irq, clr, set & ~clr); 126 } 127 128 void __init init_IRQ(void) 129 { 130 machine_desc->init_irq(); 131 } 132 133 #ifdef CONFIG_SPARSE_IRQ 134 int __init arch_probe_nr_irqs(void) 135 { 136 nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS; 137 return nr_irqs; 138 } 139 #endif 140 141 #ifdef CONFIG_HOTPLUG_CPU 142 143 static bool migrate_one_irq(struct irq_desc *desc) 144 { 145 struct irq_data *d = irq_desc_get_irq_data(desc); 146 const struct cpumask *affinity = d->affinity; 147 struct irq_chip *c; 148 bool ret = false; 149 150 /* 151 * If this is a per-CPU interrupt, or the affinity does not 152 * include this CPU, then we have nothing to do. 153 */ 154 if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity)) 155 return false; 156 157 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) { 158 affinity = cpu_online_mask; 159 ret = true; 160 } 161 162 c = irq_data_get_irq_chip(d); 163 if (c->irq_set_affinity) 164 c->irq_set_affinity(d, affinity, true); 165 else 166 pr_debug("IRQ%u: unable to set affinity\n", d->irq); 167 168 return ret; 169 } 170 171 /* 172 * The current CPU has been marked offline. Migrate IRQs off this CPU. 173 * If the affinity settings do not allow other CPUs, force them onto any 174 * available CPU. 175 * 176 * Note: we must iterate over all IRQs, whether they have an attached 177 * action structure or not, as we need to get chained interrupts too. 178 */ 179 void migrate_irqs(void) 180 { 181 unsigned int i; 182 struct irq_desc *desc; 183 unsigned long flags; 184 185 local_irq_save(flags); 186 187 for_each_irq_desc(i, desc) { 188 bool affinity_broken = false; 189 190 if (!desc) 191 continue; 192 193 raw_spin_lock(&desc->lock); 194 affinity_broken = migrate_one_irq(desc); 195 raw_spin_unlock(&desc->lock); 196 197 if (affinity_broken && printk_ratelimit()) 198 pr_warning("IRQ%u no longer affine to CPU%u\n", i, 199 smp_processor_id()); 200 } 201 202 local_irq_restore(flags); 203 } 204 #endif /* CONFIG_HOTPLUG_CPU */ 205