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 39 #include <asm/system.h> 40 #include <asm/mach/irq.h> 41 #include <asm/mach/time.h> 42 43 /* 44 * No architecture-specific irq_finish function defined in arm/arch/irqs.h. 45 */ 46 #ifndef irq_finish 47 #define irq_finish(irq) do { } while (0) 48 #endif 49 50 unsigned int arch_nr_irqs; 51 void (*init_arch_irq)(void) __initdata = NULL; 52 unsigned long irq_err_count; 53 54 int show_interrupts(struct seq_file *p, void *v) 55 { 56 int i = *(loff_t *) v, cpu; 57 struct irq_desc *desc; 58 struct irqaction * action; 59 unsigned long flags; 60 61 if (i == 0) { 62 char cpuname[12]; 63 64 seq_printf(p, " "); 65 for_each_present_cpu(cpu) { 66 sprintf(cpuname, "CPU%d", cpu); 67 seq_printf(p, " %10s", cpuname); 68 } 69 seq_putc(p, '\n'); 70 } 71 72 if (i < nr_irqs) { 73 desc = irq_to_desc(i); 74 raw_spin_lock_irqsave(&desc->lock, flags); 75 action = desc->action; 76 if (!action) 77 goto unlock; 78 79 seq_printf(p, "%3d: ", i); 80 for_each_present_cpu(cpu) 81 seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu)); 82 seq_printf(p, " %10s", desc->chip->name ? : "-"); 83 seq_printf(p, " %s", action->name); 84 for (action = action->next; action; action = action->next) 85 seq_printf(p, ", %s", action->name); 86 87 seq_putc(p, '\n'); 88 unlock: 89 raw_spin_unlock_irqrestore(&desc->lock, flags); 90 } else if (i == nr_irqs) { 91 #ifdef CONFIG_FIQ 92 show_fiq_list(p, v); 93 #endif 94 #ifdef CONFIG_SMP 95 show_ipi_list(p); 96 show_local_irqs(p); 97 #endif 98 seq_printf(p, "Err: %10lu\n", irq_err_count); 99 } 100 return 0; 101 } 102 103 /* 104 * do_IRQ handles all hardware IRQ's. Decoded IRQs should not 105 * come via this function. Instead, they should provide their 106 * own 'handler' 107 */ 108 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs) 109 { 110 struct pt_regs *old_regs = set_irq_regs(regs); 111 112 irq_enter(); 113 114 /* 115 * Some hardware gives randomly wrong interrupts. Rather 116 * than crashing, do something sensible. 117 */ 118 if (unlikely(irq >= nr_irqs)) { 119 if (printk_ratelimit()) 120 printk(KERN_WARNING "Bad IRQ%u\n", irq); 121 ack_bad_irq(irq); 122 } else { 123 generic_handle_irq(irq); 124 } 125 126 /* AT91 specific workaround */ 127 irq_finish(irq); 128 129 irq_exit(); 130 set_irq_regs(old_regs); 131 } 132 133 void set_irq_flags(unsigned int irq, unsigned int iflags) 134 { 135 struct irq_desc *desc; 136 unsigned long flags; 137 138 if (irq >= nr_irqs) { 139 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq); 140 return; 141 } 142 143 desc = irq_to_desc(irq); 144 raw_spin_lock_irqsave(&desc->lock, flags); 145 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN; 146 if (iflags & IRQF_VALID) 147 desc->status &= ~IRQ_NOREQUEST; 148 if (iflags & IRQF_PROBE) 149 desc->status &= ~IRQ_NOPROBE; 150 if (!(iflags & IRQF_NOAUTOEN)) 151 desc->status &= ~IRQ_NOAUTOEN; 152 raw_spin_unlock_irqrestore(&desc->lock, flags); 153 } 154 155 void __init init_IRQ(void) 156 { 157 init_arch_irq(); 158 } 159 160 #ifdef CONFIG_SPARSE_IRQ 161 int __init arch_probe_nr_irqs(void) 162 { 163 nr_irqs = arch_nr_irqs ? arch_nr_irqs : NR_IRQS; 164 return nr_irqs; 165 } 166 #endif 167 168 #ifdef CONFIG_HOTPLUG_CPU 169 170 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu) 171 { 172 pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->node, cpu); 173 174 raw_spin_lock_irq(&desc->lock); 175 desc->chip->set_affinity(irq, cpumask_of(cpu)); 176 raw_spin_unlock_irq(&desc->lock); 177 } 178 179 /* 180 * The CPU has been marked offline. Migrate IRQs off this CPU. If 181 * the affinity settings do not allow other CPUs, force them onto any 182 * available CPU. 183 */ 184 void migrate_irqs(void) 185 { 186 unsigned int i, cpu = smp_processor_id(); 187 struct irq_desc *desc; 188 189 for_each_irq_desc(i, desc) { 190 if (desc->node == cpu) { 191 unsigned int newcpu = cpumask_any_and(desc->affinity, 192 cpu_online_mask); 193 if (newcpu >= nr_cpu_ids) { 194 if (printk_ratelimit()) 195 printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n", 196 i, cpu); 197 198 cpumask_setall(desc->affinity); 199 newcpu = cpumask_any_and(desc->affinity, 200 cpu_online_mask); 201 } 202 203 route_irq(desc, i, newcpu); 204 } 205 } 206 } 207 #endif /* CONFIG_HOTPLUG_CPU */ 208