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/slab.h> 31 #include <linux/random.h> 32 #include <linux/smp.h> 33 #include <linux/init.h> 34 #include <linux/seq_file.h> 35 #include <linux/errno.h> 36 #include <linux/list.h> 37 #include <linux/kallsyms.h> 38 #include <linux/proc_fs.h> 39 40 #include <asm/system.h> 41 #include <asm/mach/irq.h> 42 #include <asm/mach/time.h> 43 44 /* 45 * No architecture-specific irq_finish function defined in arm/arch/irqs.h. 46 */ 47 #ifndef irq_finish 48 #define irq_finish(irq) do { } while (0) 49 #endif 50 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 irqaction * action; 58 unsigned long flags; 59 60 if (i == 0) { 61 char cpuname[12]; 62 63 seq_printf(p, " "); 64 for_each_present_cpu(cpu) { 65 sprintf(cpuname, "CPU%d", cpu); 66 seq_printf(p, " %10s", cpuname); 67 } 68 seq_putc(p, '\n'); 69 } 70 71 if (i < NR_IRQS) { 72 spin_lock_irqsave(&irq_desc[i].lock, flags); 73 action = irq_desc[i].action; 74 if (!action) 75 goto unlock; 76 77 seq_printf(p, "%3d: ", i); 78 for_each_present_cpu(cpu) 79 seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]); 80 seq_printf(p, " %10s", irq_desc[i].chip->name ? : "-"); 81 seq_printf(p, " %s", action->name); 82 for (action = action->next; action; action = action->next) 83 seq_printf(p, ", %s", action->name); 84 85 seq_putc(p, '\n'); 86 unlock: 87 spin_unlock_irqrestore(&irq_desc[i].lock, flags); 88 } else if (i == NR_IRQS) { 89 #ifdef CONFIG_ARCH_ACORN 90 show_fiq_list(p, v); 91 #endif 92 #ifdef CONFIG_SMP 93 show_ipi_list(p); 94 show_local_irqs(p); 95 #endif 96 seq_printf(p, "Err: %10lu\n", irq_err_count); 97 } 98 return 0; 99 } 100 101 /* Handle bad interrupts */ 102 static struct irq_desc bad_irq_desc = { 103 .handle_irq = handle_bad_irq, 104 .lock = SPIN_LOCK_UNLOCKED 105 }; 106 107 /* 108 * do_IRQ handles all hardware IRQ's. Decoded IRQs should not 109 * come via this function. Instead, they should provide their 110 * own 'handler' 111 */ 112 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs) 113 { 114 struct pt_regs *old_regs = set_irq_regs(regs); 115 116 irq_enter(); 117 118 /* 119 * Some hardware gives randomly wrong interrupts. Rather 120 * than crashing, do something sensible. 121 */ 122 if (irq >= NR_IRQS) 123 handle_bad_irq(irq, &bad_irq_desc); 124 else 125 generic_handle_irq(irq); 126 127 /* AT91 specific workaround */ 128 irq_finish(irq); 129 130 irq_exit(); 131 set_irq_regs(old_regs); 132 } 133 134 void set_irq_flags(unsigned int irq, unsigned int iflags) 135 { 136 struct irq_desc *desc; 137 unsigned long flags; 138 139 if (irq >= NR_IRQS) { 140 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq); 141 return; 142 } 143 144 desc = irq_desc + irq; 145 spin_lock_irqsave(&desc->lock, flags); 146 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN; 147 if (iflags & IRQF_VALID) 148 desc->status &= ~IRQ_NOREQUEST; 149 if (iflags & IRQF_PROBE) 150 desc->status &= ~IRQ_NOPROBE; 151 if (!(iflags & IRQF_NOAUTOEN)) 152 desc->status &= ~IRQ_NOAUTOEN; 153 spin_unlock_irqrestore(&desc->lock, flags); 154 } 155 156 void __init init_IRQ(void) 157 { 158 int irq; 159 160 for (irq = 0; irq < NR_IRQS; irq++) 161 irq_desc[irq].status |= IRQ_NOREQUEST | IRQ_NOPROBE; 162 163 #ifdef CONFIG_SMP 164 bad_irq_desc.affinity = CPU_MASK_ALL; 165 bad_irq_desc.cpu = smp_processor_id(); 166 #endif 167 init_arch_irq(); 168 } 169 170 #ifdef CONFIG_HOTPLUG_CPU 171 172 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu) 173 { 174 pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu); 175 176 spin_lock_irq(&desc->lock); 177 desc->chip->set_affinity(irq, cpumask_of_cpu(cpu)); 178 spin_unlock_irq(&desc->lock); 179 } 180 181 /* 182 * The CPU has been marked offline. Migrate IRQs off this CPU. If 183 * the affinity settings do not allow other CPUs, force them onto any 184 * available CPU. 185 */ 186 void migrate_irqs(void) 187 { 188 unsigned int i, cpu = smp_processor_id(); 189 190 for (i = 0; i < NR_IRQS; i++) { 191 struct irq_desc *desc = irq_desc + i; 192 193 if (desc->cpu == cpu) { 194 unsigned int newcpu = any_online_cpu(desc->affinity); 195 196 if (newcpu == NR_CPUS) { 197 if (printk_ratelimit()) 198 printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n", 199 i, cpu); 200 201 cpus_setall(desc->affinity); 202 newcpu = any_online_cpu(desc->affinity); 203 } 204 205 route_irq(desc, i, newcpu); 206 } 207 } 208 } 209 #endif /* CONFIG_HOTPLUG_CPU */ 210