f3c2ee3634
For cases with SPARSE_IRQ enabled, irqs preallocated with arch_probe_nr_irqs() are already marked as allocated in the allocated_irqs bitmap. As a consequence, irq chip drivers that allocate irqs will feel one of two behaviors: 1. An allocation will succeed with the starting irq_base one more than the preallocated irqs. This will thus waste the preceeding interrupt resources that were preallocated, unless a legacy chip driver happens to assume ownership of these by some platform definition. The GIC driver is a typical primary chip driver, and abides to the allocation APIs. So this can be a problem in many trivial usecases. 2. An allocation will fail with < 0. This can also happen in the GIC driver, which interprets this value as meaning the irq_descs are already preallocated. But in Device Tree configurations, the fallback irq_base is -1. This results in an invalid irq_base value. Looking forward, we are moving towards a world where preallocation of irqs is no longer necessary. irq_domain is scoped to handle all irq_desc allocations in the future. Thus, we should support configurations where the platform wants to preallocate no irqs. One easy way to achieve this is to allow for machine_desc->nr_irqs < 0, which indicates not to preallocate any interrupts. Change-Id: Ie793932c58de72c1b91b6e039b77a8e5d64ecc75 Signed-off-by: Michael Bohan <mbohan@codeaurora.org> (cherry picked from commit 0bb2b56f7048b2f85be6784eaa8e4a5f0fa8688d)
211 lines
5.2 KiB
C
211 lines
5.2 KiB
C
/*
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* linux/arch/arm/kernel/irq.c
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*
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* Copyright (C) 1992 Linus Torvalds
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* Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
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*
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* Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
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* Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
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* Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This file contains the code used by various IRQ handling routines:
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* asking for different IRQ's should be done through these routines
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* instead of just grabbing them. Thus setups with different IRQ numbers
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* shouldn't result in any weird surprises, and installing new handlers
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* should be easier.
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*
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* IRQ's are in fact implemented a bit like signal handlers for the kernel.
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* Naturally it's not a 1:1 relation, but there are similarities.
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*/
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#include <linux/kernel_stat.h>
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#include <linux/signal.h>
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#include <linux/ioport.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/random.h>
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#include <linux/smp.h>
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#include <linux/init.h>
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#include <linux/seq_file.h>
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#include <linux/errno.h>
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#include <linux/list.h>
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#include <linux/kallsyms.h>
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#include <linux/proc_fs.h>
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#include <asm/exception.h>
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#include <asm/mach/arch.h>
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#include <asm/mach/irq.h>
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#include <asm/mach/time.h>
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#include <asm/perftypes.h>
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/*
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* No architecture-specific irq_finish function defined in arm/arch/irqs.h.
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*/
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#ifndef irq_finish
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#define irq_finish(irq) do { } while (0)
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#endif
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unsigned long irq_err_count;
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int arch_show_interrupts(struct seq_file *p, int prec)
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{
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#ifdef CONFIG_FIQ
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show_fiq_list(p, prec);
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#endif
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#ifdef CONFIG_SMP
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show_ipi_list(p, prec);
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#endif
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seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
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return 0;
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}
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/*
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* handle_IRQ handles all hardware IRQ's. Decoded IRQs should
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* not come via this function. Instead, they should provide their
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* own 'handler'. Used by platform code implementing C-based 1st
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* level decoding.
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*/
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void handle_IRQ(unsigned int irq, struct pt_regs *regs)
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{
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struct pt_regs *old_regs = set_irq_regs(regs);
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perf_mon_interrupt_in();
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irq_enter();
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/*
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* Some hardware gives randomly wrong interrupts. Rather
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* than crashing, do something sensible.
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*/
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if (unlikely(irq >= nr_irqs)) {
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if (printk_ratelimit())
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printk(KERN_WARNING "Bad IRQ%u\n", irq);
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ack_bad_irq(irq);
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} else {
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generic_handle_irq(irq);
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}
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/* AT91 specific workaround */
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irq_finish(irq);
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irq_exit();
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set_irq_regs(old_regs);
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perf_mon_interrupt_out();
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}
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/*
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* asm_do_IRQ is the interface to be used from assembly code.
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*/
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asmlinkage void __exception_irq_entry
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asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
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{
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handle_IRQ(irq, regs);
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}
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void set_irq_flags(unsigned int irq, unsigned int iflags)
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{
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unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
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if (irq >= nr_irqs) {
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printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
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return;
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}
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if (iflags & IRQF_VALID)
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clr |= IRQ_NOREQUEST;
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if (iflags & IRQF_PROBE)
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clr |= IRQ_NOPROBE;
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if (!(iflags & IRQF_NOAUTOEN))
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clr |= IRQ_NOAUTOEN;
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/* Order is clear bits in "clr" then set bits in "set" */
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irq_modify_status(irq, clr, set & ~clr);
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}
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void __init init_IRQ(void)
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{
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machine_desc->init_irq();
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}
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#ifdef CONFIG_SPARSE_IRQ
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int __init arch_probe_nr_irqs(void)
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{
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/*
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* machine_desc->nr_irqs < 0 is a special case that
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* specifies not to preallocate any irq_descs.
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*/
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if (machine_desc->nr_irqs < 0) {
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nr_irqs = 0;
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return nr_irqs;
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} else {
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nr_irqs = machine_desc->nr_irqs ?
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machine_desc->nr_irqs : NR_IRQS;
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return nr_irqs;
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}
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}
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#endif
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#ifdef CONFIG_HOTPLUG_CPU
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static bool migrate_one_irq(struct irq_desc *desc)
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{
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struct irq_data *d = irq_desc_get_irq_data(desc);
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const struct cpumask *affinity = d->affinity;
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struct irq_chip *c;
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bool ret = false;
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/*
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* If this is a per-CPU interrupt, or the affinity does not
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* include this CPU, then we have nothing to do.
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*/
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if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
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return false;
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if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
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affinity = cpu_online_mask;
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ret = true;
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}
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c = irq_data_get_irq_chip(d);
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if (!c->irq_set_affinity)
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pr_debug("IRQ%u: unable to set affinity\n", d->irq);
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else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret)
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cpumask_copy(d->affinity, affinity);
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return ret;
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}
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/*
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* The current CPU has been marked offline. Migrate IRQs off this CPU.
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* If the affinity settings do not allow other CPUs, force them onto any
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* available CPU.
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*
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* Note: we must iterate over all IRQs, whether they have an attached
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* action structure or not, as we need to get chained interrupts too.
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*/
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void migrate_irqs(void)
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{
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unsigned int i;
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struct irq_desc *desc;
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unsigned long flags;
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local_irq_save(flags);
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for_each_irq_desc(i, desc) {
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bool affinity_broken;
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raw_spin_lock(&desc->lock);
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affinity_broken = migrate_one_irq(desc);
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raw_spin_unlock(&desc->lock);
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if (affinity_broken && printk_ratelimit())
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pr_warning("IRQ%u no longer affine to CPU%u\n", i,
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smp_processor_id());
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}
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local_irq_restore(flags);
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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