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