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