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Diffstat (limited to 'arch/arm/kernel/irq.c')
| -rw-r--r-- | arch/arm/kernel/irq.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c new file mode 100644 index 00000000..8349d4e9 --- /dev/null +++ b/arch/arm/kernel/irq.c @@ -0,0 +1,196 @@ +/* + * linux/arch/arm/kernel/irq.c + * + * Copyright (C) 1992 Linus Torvalds + * Modifications for ARM processor Copyright (C) 1995-2000 Russell King. + * + * Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation. + * Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and + * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This file contains the code used by various IRQ handling routines: + * asking for different IRQ's should be done through these routines + * instead of just grabbing them. Thus setups with different IRQ numbers + * shouldn't result in any weird surprises, and installing new handlers + * should be easier. + * + * IRQ's are in fact implemented a bit like signal handlers for the kernel. + * Naturally it's not a 1:1 relation, but there are similarities. + */ +#include <linux/kernel_stat.h> +#include <linux/signal.h> +#include <linux/ioport.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/random.h> +#include <linux/smp.h> +#include <linux/init.h> +#include <linux/seq_file.h> +#include <linux/errno.h> +#include <linux/list.h> +#include <linux/kallsyms.h> +#include <linux/proc_fs.h> + +#include <asm/exception.h> +#include <asm/mach/arch.h> +#include <asm/mach/irq.h> +#include <asm/mach/time.h> + +/* + * No architecture-specific irq_finish function defined in arm/arch/irqs.h. + */ +#ifndef irq_finish +#define irq_finish(irq) do { } while (0) +#endif + +unsigned long irq_err_count; + +int arch_show_interrupts(struct seq_file *p, int prec) +{ +#ifdef CONFIG_FIQ + show_fiq_list(p, prec); +#endif +#ifdef CONFIG_SMP + show_ipi_list(p, prec); +#endif + seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count); + return 0; +} + +/* + * handle_IRQ handles all hardware IRQ's. Decoded IRQs should + * not come via this function. Instead, they should provide their + * own 'handler'. Used by platform code implementing C-based 1st + * level decoding. + */ +void handle_IRQ(unsigned int irq, struct pt_regs *regs) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + + irq_enter(); + + /* + * Some hardware gives randomly wrong interrupts. Rather + * than crashing, do something sensible. + */ + if (unlikely(irq >= nr_irqs)) { + if (printk_ratelimit()) + printk(KERN_WARNING "Bad IRQ%u\n", irq); + ack_bad_irq(irq); + } else { + generic_handle_irq(irq); + } + + /* AT91 specific workaround */ + irq_finish(irq); + + irq_exit(); + set_irq_regs(old_regs); +} + +/* + * asm_do_IRQ is the interface to be used from assembly code. + */ +asmlinkage void __exception_irq_entry +asm_do_IRQ(unsigned int irq, struct pt_regs *regs) +{ + handle_IRQ(irq, regs); +} + +void set_irq_flags(unsigned int irq, unsigned int iflags) +{ + unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN; + + if (irq >= nr_irqs) { + printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq); + return; + } + + if (iflags & IRQF_VALID) + clr |= IRQ_NOREQUEST; + if (iflags & IRQF_PROBE) + clr |= IRQ_NOPROBE; + if (!(iflags & IRQF_NOAUTOEN)) + clr |= IRQ_NOAUTOEN; + /* Order is clear bits in "clr" then set bits in "set" */ + irq_modify_status(irq, clr, set & ~clr); +} + +void __init init_IRQ(void) +{ + machine_desc->init_irq(); +} + +#ifdef CONFIG_SPARSE_IRQ +int __init arch_probe_nr_irqs(void) +{ + nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS; + return nr_irqs; +} +#endif + +#ifdef CONFIG_HOTPLUG_CPU + +static bool migrate_one_irq(struct irq_desc *desc) +{ + struct irq_data *d = irq_desc_get_irq_data(desc); + const struct cpumask *affinity = d->affinity; + struct irq_chip *c; + bool ret = false; + + /* + * If this is a per-CPU interrupt, or the affinity does not + * include this CPU, then we have nothing to do. + */ + if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity)) + return false; + + if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) { + affinity = cpu_online_mask; + ret = true; + } + + c = irq_data_get_irq_chip(d); + if (!c->irq_set_affinity) + pr_debug("IRQ%u: unable to set affinity\n", d->irq); + else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret) + cpumask_copy(d->affinity, affinity); + + return ret; +} + +/* + * The current CPU has been marked offline. Migrate IRQs off this CPU. + * If the affinity settings do not allow other CPUs, force them onto any + * available CPU. + * + * Note: we must iterate over all IRQs, whether they have an attached + * action structure or not, as we need to get chained interrupts too. + */ +void migrate_irqs(void) +{ + unsigned int i; + struct irq_desc *desc; + unsigned long flags; + + local_irq_save(flags); + + for_each_irq_desc(i, desc) { + bool affinity_broken; + + raw_spin_lock(&desc->lock); + affinity_broken = migrate_one_irq(desc); + raw_spin_unlock(&desc->lock); + + if (affinity_broken && printk_ratelimit()) + pr_warning("IRQ%u no longer affine to CPU%u\n", i, + smp_processor_id()); + } + + local_irq_restore(flags); +} +#endif /* CONFIG_HOTPLUG_CPU */ |