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 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 int prec, n; 61 62 for (prec = 3, n = 1000; prec < 10 && n <= nr_irqs; prec++) 63 n *= 10; 64 65 #ifdef CONFIG_SMP 66 if (prec < 4) 67 prec = 4; 68 #endif 69 70 if (i == 0) { 71 char cpuname[12]; 72 73 seq_printf(p, "%*s ", prec, ""); 74 for_each_present_cpu(cpu) { 75 sprintf(cpuname, "CPU%d", cpu); 76 seq_printf(p, " %10s", cpuname); 77 } 78 seq_putc(p, '\n'); 79 } 80 81 if (i < nr_irqs) { 82 desc = irq_to_desc(i); 83 raw_spin_lock_irqsave(&desc->lock, flags); 84 action = desc->action; 85 if (!action) 86 goto unlock; 87 88 seq_printf(p, "%*d: ", prec, i); 89 for_each_present_cpu(cpu) 90 seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu)); 91 seq_printf(p, " %10s", desc->irq_data.chip->name ? : "-"); 92 seq_printf(p, " %s", action->name); 93 for (action = action->next; action; action = action->next) 94 seq_printf(p, ", %s", action->name); 95 96 seq_putc(p, '\n'); 97 unlock: 98 raw_spin_unlock_irqrestore(&desc->lock, flags); 99 } else if (i == nr_irqs) { 100 #ifdef CONFIG_FIQ 101 show_fiq_list(p, prec); 102 #endif 103 #ifdef CONFIG_SMP 104 show_ipi_list(p, prec); 105 #endif 106 #ifdef CONFIG_LOCAL_TIMERS 107 show_local_irqs(p, prec); 108 #endif 109 seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count); 110 } 111 return 0; 112 } 113 114 /* 115 * do_IRQ handles all hardware IRQ's. Decoded IRQs should not 116 * come via this function. Instead, they should provide their 117 * own 'handler' 118 */ 119 asmlinkage void __exception_irq_entry 120 asm_do_IRQ(unsigned int irq, struct pt_regs *regs) 121 { 122 struct pt_regs *old_regs = set_irq_regs(regs); 123 124 irq_enter(); 125 126 /* 127 * Some hardware gives randomly wrong interrupts. Rather 128 * than crashing, do something sensible. 129 */ 130 if (unlikely(irq >= nr_irqs)) { 131 if (printk_ratelimit()) 132 printk(KERN_WARNING "Bad IRQ%u\n", irq); 133 ack_bad_irq(irq); 134 } else { 135 generic_handle_irq(irq); 136 } 137 138 /* AT91 specific workaround */ 139 irq_finish(irq); 140 141 irq_exit(); 142 set_irq_regs(old_regs); 143 } 144 145 void set_irq_flags(unsigned int irq, unsigned int iflags) 146 { 147 struct irq_desc *desc; 148 unsigned long flags; 149 150 if (irq >= nr_irqs) { 151 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq); 152 return; 153 } 154 155 desc = irq_to_desc(irq); 156 raw_spin_lock_irqsave(&desc->lock, flags); 157 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN; 158 if (iflags & IRQF_VALID) 159 desc->status &= ~IRQ_NOREQUEST; 160 if (iflags & IRQF_PROBE) 161 desc->status &= ~IRQ_NOPROBE; 162 if (!(iflags & IRQF_NOAUTOEN)) 163 desc->status &= ~IRQ_NOAUTOEN; 164 raw_spin_unlock_irqrestore(&desc->lock, flags); 165 } 166 167 void __init init_IRQ(void) 168 { 169 machine_desc->init_irq(); 170 } 171 172 #ifdef CONFIG_SPARSE_IRQ 173 int __init arch_probe_nr_irqs(void) 174 { 175 nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS; 176 return nr_irqs; 177 } 178 #endif 179 180 #ifdef CONFIG_HOTPLUG_CPU 181 182 static bool migrate_one_irq(struct irq_data *d) 183 { 184 unsigned int cpu = cpumask_any_and(d->affinity, cpu_online_mask); 185 bool ret = false; 186 187 if (cpu >= nr_cpu_ids) { 188 cpu = cpumask_any(cpu_online_mask); 189 ret = true; 190 } 191 192 pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", d->irq, d->node, cpu); 193 194 d->chip->irq_set_affinity(d, cpumask_of(cpu), true); 195 196 return ret; 197 } 198 199 /* 200 * The CPU has been marked offline. Migrate IRQs off this CPU. If 201 * the affinity settings do not allow other CPUs, force them onto any 202 * available CPU. 203 */ 204 void migrate_irqs(void) 205 { 206 unsigned int i, cpu = smp_processor_id(); 207 struct irq_desc *desc; 208 unsigned long flags; 209 210 local_irq_save(flags); 211 212 for_each_irq_desc(i, desc) { 213 struct irq_data *d = &desc->irq_data; 214 bool affinity_broken = false; 215 216 raw_spin_lock(&desc->lock); 217 do { 218 if (desc->action == NULL) 219 break; 220 221 if (d->node != cpu) 222 break; 223 224 affinity_broken = migrate_one_irq(d); 225 } while (0); 226 raw_spin_unlock(&desc->lock); 227 228 if (affinity_broken && printk_ratelimit()) 229 pr_warning("IRQ%u no longer affine to CPU%u\n", i, cpu); 230 } 231 232 local_irq_restore(flags); 233 } 234 #endif /* CONFIG_HOTPLUG_CPU */ 235