| /* |
| * linux/arch/arm/kernel/irq.c |
| * |
| * Copyright (C) 1992 Linus Torvalds |
| * Modifications for ARM processor Copyright (C) 1995-2000 Russell King. |
| * 'Borrowed' for ARM26 and (C) 2003 Ian Molton. |
| * |
| * 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/module.h> |
| #include <linux/ptrace.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/signal.h> |
| #include <linux/sched.h> |
| #include <linux/ioport.h> |
| #include <linux/interrupt.h> |
| #include <linux/slab.h> |
| #include <linux/random.h> |
| #include <linux/smp.h> |
| #include <linux/init.h> |
| #include <linux/seq_file.h> |
| #include <linux/errno.h> |
| |
| #include <asm/irq.h> |
| #include <asm/system.h> |
| #include <asm/irqchip.h> |
| |
| //FIXME - this ought to be in a header IMO |
| void __init arc_init_irq(void); |
| |
| /* |
| * Maximum IRQ count. Currently, this is arbitary. However, it should |
| * not be set too low to prevent false triggering. Conversely, if it |
| * is set too high, then you could miss a stuck IRQ. |
| * |
| * FIXME Maybe we ought to set a timer and re-enable the IRQ at a later time? |
| */ |
| #define MAX_IRQ_CNT 100000 |
| |
| static volatile unsigned long irq_err_count; |
| static DEFINE_SPINLOCK(irq_controller_lock); |
| |
| struct irqdesc irq_desc[NR_IRQS]; |
| |
| /* |
| * Dummy mask/unmask handler |
| */ |
| void dummy_mask_unmask_irq(unsigned int irq) |
| { |
| } |
| |
| void do_bad_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs) |
| { |
| irq_err_count += 1; |
| printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq); |
| } |
| |
| static struct irqchip bad_chip = { |
| .ack = dummy_mask_unmask_irq, |
| .mask = dummy_mask_unmask_irq, |
| .unmask = dummy_mask_unmask_irq, |
| }; |
| |
| static struct irqdesc bad_irq_desc = { |
| .chip = &bad_chip, |
| .handle = do_bad_IRQ, |
| .depth = 1, |
| }; |
| |
| /** |
| * disable_irq - disable an irq and wait for completion |
| * @irq: Interrupt to disable |
| * |
| * Disable the selected interrupt line. We do this lazily. |
| * |
| * This function may be called from IRQ context. |
| */ |
| void disable_irq(unsigned int irq) |
| { |
| struct irqdesc *desc = irq_desc + irq; |
| unsigned long flags; |
| spin_lock_irqsave(&irq_controller_lock, flags); |
| if (!desc->depth++) |
| desc->enabled = 0; |
| spin_unlock_irqrestore(&irq_controller_lock, flags); |
| } |
| |
| /** |
| * enable_irq - enable interrupt handling on an irq |
| * @irq: Interrupt to enable |
| * |
| * Re-enables the processing of interrupts on this IRQ line. |
| * Note that this may call the interrupt handler, so you may |
| * get unexpected results if you hold IRQs disabled. |
| * |
| * This function may be called from IRQ context. |
| */ |
| void enable_irq(unsigned int irq) |
| { |
| struct irqdesc *desc = irq_desc + irq; |
| unsigned long flags; |
| int pending = 0; |
| |
| spin_lock_irqsave(&irq_controller_lock, flags); |
| if (unlikely(!desc->depth)) { |
| printk("enable_irq(%u) unbalanced from %p\n", irq, |
| __builtin_return_address(0)); //FIXME bum addresses reported - why? |
| } else if (!--desc->depth) { |
| desc->probing = 0; |
| desc->enabled = 1; |
| desc->chip->unmask(irq); |
| pending = desc->pending; |
| desc->pending = 0; |
| /* |
| * If the interrupt was waiting to be processed, |
| * retrigger it. |
| */ |
| if (pending) |
| desc->chip->rerun(irq); |
| } |
| spin_unlock_irqrestore(&irq_controller_lock, flags); |
| } |
| |
| int show_interrupts(struct seq_file *p, void *v) |
| { |
| int i = *(loff_t *) v; |
| struct irqaction * action; |
| |
| if (i < NR_IRQS) { |
| action = irq_desc[i].action; |
| if (!action) |
| goto out; |
| seq_printf(p, "%3d: %10u ", i, kstat_irqs(i)); |
| seq_printf(p, " %s", action->name); |
| for (action = action->next; action; action = action->next) { |
| seq_printf(p, ", %s", action->name); |
| } |
| seq_putc(p, '\n'); |
| } else if (i == NR_IRQS) { |
| show_fiq_list(p, v); |
| seq_printf(p, "Err: %10lu\n", irq_err_count); |
| } |
| out: |
| return 0; |
| } |
| |
| /* |
| * IRQ lock detection. |
| * |
| * Hopefully, this should get us out of a few locked situations. |
| * However, it may take a while for this to happen, since we need |
| * a large number if IRQs to appear in the same jiffie with the |
| * same instruction pointer (or within 2 instructions). |
| */ |
| static int check_irq_lock(struct irqdesc *desc, int irq, struct pt_regs *regs) |
| { |
| unsigned long instr_ptr = instruction_pointer(regs); |
| |
| if (desc->lck_jif == jiffies && |
| desc->lck_pc >= instr_ptr && desc->lck_pc < instr_ptr + 8) { |
| desc->lck_cnt += 1; |
| |
| if (desc->lck_cnt > MAX_IRQ_CNT) { |
| printk(KERN_ERR "IRQ LOCK: IRQ%d is locking the system, disabled\n", irq); |
| return 1; |
| } |
| } else { |
| desc->lck_cnt = 0; |
| desc->lck_pc = instruction_pointer(regs); |
| desc->lck_jif = jiffies; |
| } |
| return 0; |
| } |
| |
| static void |
| __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs) |
| { |
| unsigned int status; |
| int ret; |
| |
| spin_unlock(&irq_controller_lock); |
| if (!(action->flags & SA_INTERRUPT)) |
| local_irq_enable(); |
| |
| status = 0; |
| do { |
| ret = action->handler(irq, action->dev_id, regs); |
| if (ret == IRQ_HANDLED) |
| status |= action->flags; |
| action = action->next; |
| } while (action); |
| |
| if (status & SA_SAMPLE_RANDOM) |
| add_interrupt_randomness(irq); |
| |
| spin_lock_irq(&irq_controller_lock); |
| } |
| |
| /* |
| * This is for software-decoded IRQs. The caller is expected to |
| * handle the ack, clear, mask and unmask issues. |
| */ |
| void |
| do_simple_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs) |
| { |
| struct irqaction *action; |
| const int cpu = smp_processor_id(); |
| |
| desc->triggered = 1; |
| |
| kstat_cpu(cpu).irqs[irq]++; |
| |
| action = desc->action; |
| if (action) |
| __do_irq(irq, desc->action, regs); |
| } |
| |
| /* |
| * Most edge-triggered IRQ implementations seem to take a broken |
| * approach to this. Hence the complexity. |
| */ |
| void |
| do_edge_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs) |
| { |
| const int cpu = smp_processor_id(); |
| |
| desc->triggered = 1; |
| |
| /* |
| * If we're currently running this IRQ, or its disabled, |
| * we shouldn't process the IRQ. Instead, turn on the |
| * hardware masks. |
| */ |
| if (unlikely(desc->running || !desc->enabled)) |
| goto running; |
| |
| /* |
| * Acknowledge and clear the IRQ, but don't mask it. |
| */ |
| desc->chip->ack(irq); |
| |
| /* |
| * Mark the IRQ currently in progress. |
| */ |
| desc->running = 1; |
| |
| kstat_cpu(cpu).irqs[irq]++; |
| |
| do { |
| struct irqaction *action; |
| |
| action = desc->action; |
| if (!action) |
| break; |
| |
| if (desc->pending && desc->enabled) { |
| desc->pending = 0; |
| desc->chip->unmask(irq); |
| } |
| |
| __do_irq(irq, action, regs); |
| } while (desc->pending); |
| |
| desc->running = 0; |
| |
| /* |
| * If we were disabled or freed, shut down the handler. |
| */ |
| if (likely(desc->action && !check_irq_lock(desc, irq, regs))) |
| return; |
| |
| running: |
| /* |
| * We got another IRQ while this one was masked or |
| * currently running. Delay it. |
| */ |
| desc->pending = 1; |
| desc->chip->mask(irq); |
| desc->chip->ack(irq); |
| } |
| |
| /* |
| * Level-based IRQ handler. Nice and simple. |
| */ |
| void |
| do_level_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs) |
| { |
| struct irqaction *action; |
| const int cpu = smp_processor_id(); |
| |
| desc->triggered = 1; |
| |
| /* |
| * Acknowledge, clear _AND_ disable the interrupt. |
| */ |
| desc->chip->ack(irq); |
| |
| if (likely(desc->enabled)) { |
| kstat_cpu(cpu).irqs[irq]++; |
| |
| /* |
| * Return with this interrupt masked if no action |
| */ |
| action = desc->action; |
| if (action) { |
| __do_irq(irq, desc->action, regs); |
| |
| if (likely(desc->enabled && |
| !check_irq_lock(desc, irq, regs))) |
| desc->chip->unmask(irq); |
| } |
| } |
| } |
| |
| /* |
| * do_IRQ handles all hardware IRQ's. Decoded IRQs should not |
| * come via this function. Instead, they should provide their |
| * own 'handler' |
| */ |
| asmlinkage void asm_do_IRQ(int irq, struct pt_regs *regs) |
| { |
| struct irqdesc *desc = irq_desc + irq; |
| |
| /* |
| * Some hardware gives randomly wrong interrupts. Rather |
| * than crashing, do something sensible. |
| */ |
| if (irq >= NR_IRQS) |
| desc = &bad_irq_desc; |
| |
| irq_enter(); |
| spin_lock(&irq_controller_lock); |
| desc->handle(irq, desc, regs); |
| spin_unlock(&irq_controller_lock); |
| irq_exit(); |
| } |
| |
| void __set_irq_handler(unsigned int irq, irq_handler_t handle, int is_chained) |
| { |
| struct irqdesc *desc; |
| unsigned long flags; |
| |
| if (irq >= NR_IRQS) { |
| printk(KERN_ERR "Trying to install handler for IRQ%d\n", irq); |
| return; |
| } |
| |
| if (handle == NULL) |
| handle = do_bad_IRQ; |
| |
| desc = irq_desc + irq; |
| |
| if (is_chained && desc->chip == &bad_chip) |
| printk(KERN_WARNING "Trying to install chained handler for IRQ%d\n", irq); |
| |
| spin_lock_irqsave(&irq_controller_lock, flags); |
| if (handle == do_bad_IRQ) { |
| desc->chip->mask(irq); |
| desc->chip->ack(irq); |
| desc->depth = 1; |
| desc->enabled = 0; |
| } |
| desc->handle = handle; |
| if (handle != do_bad_IRQ && is_chained) { |
| desc->valid = 0; |
| desc->probe_ok = 0; |
| desc->depth = 0; |
| desc->chip->unmask(irq); |
| } |
| spin_unlock_irqrestore(&irq_controller_lock, flags); |
| } |
| |
| void set_irq_chip(unsigned int irq, struct irqchip *chip) |
| { |
| struct irqdesc *desc; |
| unsigned long flags; |
| |
| if (irq >= NR_IRQS) { |
| printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq); |
| return; |
| } |
| |
| if (chip == NULL) |
| chip = &bad_chip; |
| |
| desc = irq_desc + irq; |
| spin_lock_irqsave(&irq_controller_lock, flags); |
| desc->chip = chip; |
| spin_unlock_irqrestore(&irq_controller_lock, flags); |
| } |
| |
| int set_irq_type(unsigned int irq, unsigned int type) |
| { |
| struct irqdesc *desc; |
| unsigned long flags; |
| int ret = -ENXIO; |
| |
| if (irq >= NR_IRQS) { |
| printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq); |
| return -ENODEV; |
| } |
| |
| desc = irq_desc + irq; |
| if (desc->chip->type) { |
| spin_lock_irqsave(&irq_controller_lock, flags); |
| ret = desc->chip->type(irq, type); |
| spin_unlock_irqrestore(&irq_controller_lock, flags); |
| } |
| |
| return ret; |
| } |
| |
| void set_irq_flags(unsigned int irq, unsigned int iflags) |
| { |
| struct irqdesc *desc; |
| unsigned long flags; |
| |
| if (irq >= NR_IRQS) { |
| printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq); |
| return; |
| } |
| |
| desc = irq_desc + irq; |
| spin_lock_irqsave(&irq_controller_lock, flags); |
| desc->valid = (iflags & IRQF_VALID) != 0; |
| desc->probe_ok = (iflags & IRQF_PROBE) != 0; |
| desc->noautoenable = (iflags & IRQF_NOAUTOEN) != 0; |
| spin_unlock_irqrestore(&irq_controller_lock, flags); |
| } |
| |
| int setup_irq(unsigned int irq, struct irqaction *new) |
| { |
| int shared = 0; |
| struct irqaction *old, **p; |
| unsigned long flags; |
| struct irqdesc *desc; |
| |
| /* |
| * Some drivers like serial.c use request_irq() heavily, |
| * so we have to be careful not to interfere with a |
| * running system. |
| */ |
| if (new->flags & SA_SAMPLE_RANDOM) { |
| /* |
| * This function might sleep, we want to call it first, |
| * outside of the atomic block. |
| * Yes, this might clear the entropy pool if the wrong |
| * driver is attempted to be loaded, without actually |
| * installing a new handler, but is this really a problem, |
| * only the sysadmin is able to do this. |
| */ |
| rand_initialize_irq(irq); |
| } |
| |
| /* |
| * The following block of code has to be executed atomically |
| */ |
| desc = irq_desc + irq; |
| spin_lock_irqsave(&irq_controller_lock, flags); |
| p = &desc->action; |
| if ((old = *p) != NULL) { |
| /* Can't share interrupts unless both agree to */ |
| if (!(old->flags & new->flags & SA_SHIRQ)) { |
| spin_unlock_irqrestore(&irq_controller_lock, flags); |
| return -EBUSY; |
| } |
| |
| /* add new interrupt at end of irq queue */ |
| do { |
| p = &old->next; |
| old = *p; |
| } while (old); |
| shared = 1; |
| } |
| |
| *p = new; |
| |
| if (!shared) { |
| desc->probing = 0; |
| desc->running = 0; |
| desc->pending = 0; |
| desc->depth = 1; |
| if (!desc->noautoenable) { |
| desc->depth = 0; |
| desc->enabled = 1; |
| desc->chip->unmask(irq); |
| } |
| } |
| |
| spin_unlock_irqrestore(&irq_controller_lock, flags); |
| return 0; |
| } |
| |
| /** |
| * request_irq - allocate an interrupt line |
| * @irq: Interrupt line to allocate |
| * @handler: Function to be called when the IRQ occurs |
| * @irqflags: Interrupt type flags |
| * @devname: An ascii name for the claiming device |
| * @dev_id: A cookie passed back to the handler function |
| * |
| * This call allocates interrupt resources and enables the |
| * interrupt line and IRQ handling. From the point this |
| * call is made your handler function may be invoked. Since |
| * your handler function must clear any interrupt the board |
| * raises, you must take care both to initialise your hardware |
| * and to set up the interrupt handler in the right order. |
| * |
| * Dev_id must be globally unique. Normally the address of the |
| * device data structure is used as the cookie. Since the handler |
| * receives this value it makes sense to use it. |
| * |
| * If your interrupt is shared you must pass a non NULL dev_id |
| * as this is required when freeing the interrupt. |
| * |
| * Flags: |
| * |
| * SA_SHIRQ Interrupt is shared |
| * |
| * SA_INTERRUPT Disable local interrupts while processing |
| * |
| * SA_SAMPLE_RANDOM The interrupt can be used for entropy |
| * |
| */ |
| |
| //FIXME - handler used to return void - whats the significance of the change? |
| int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *), |
| unsigned long irq_flags, const char * devname, void *dev_id) |
| { |
| unsigned long retval; |
| struct irqaction *action; |
| |
| if (irq >= NR_IRQS || !irq_desc[irq].valid || !handler || |
| (irq_flags & SA_SHIRQ && !dev_id)) |
| return -EINVAL; |
| |
| action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL); |
| if (!action) |
| return -ENOMEM; |
| |
| action->handler = handler; |
| action->flags = irq_flags; |
| cpus_clear(action->mask); |
| action->name = devname; |
| action->next = NULL; |
| action->dev_id = dev_id; |
| |
| retval = setup_irq(irq, action); |
| |
| if (retval) |
| kfree(action); |
| return retval; |
| } |
| |
| EXPORT_SYMBOL(request_irq); |
| |
| /** |
| * free_irq - free an interrupt |
| * @irq: Interrupt line to free |
| * @dev_id: Device identity to free |
| * |
| * Remove an interrupt handler. The handler is removed and if the |
| * interrupt line is no longer in use by any driver it is disabled. |
| * On a shared IRQ the caller must ensure the interrupt is disabled |
| * on the card it drives before calling this function. |
| * |
| * This function may be called from interrupt context. |
| */ |
| void free_irq(unsigned int irq, void *dev_id) |
| { |
| struct irqaction * action, **p; |
| unsigned long flags; |
| |
| if (irq >= NR_IRQS || !irq_desc[irq].valid) { |
| printk(KERN_ERR "Trying to free IRQ%d\n",irq); |
| #ifdef CONFIG_DEBUG_ERRORS |
| __backtrace(); |
| #endif |
| return; |
| } |
| |
| spin_lock_irqsave(&irq_controller_lock, flags); |
| for (p = &irq_desc[irq].action; (action = *p) != NULL; p = &action->next) { |
| if (action->dev_id != dev_id) |
| continue; |
| |
| /* Found it - now free it */ |
| *p = action->next; |
| kfree(action); |
| goto out; |
| } |
| printk(KERN_ERR "Trying to free free IRQ%d\n",irq); |
| #ifdef CONFIG_DEBUG_ERRORS |
| __backtrace(); |
| #endif |
| out: |
| spin_unlock_irqrestore(&irq_controller_lock, flags); |
| } |
| |
| EXPORT_SYMBOL(free_irq); |
| |
| /* Start the interrupt probing. Unlike other architectures, |
| * we don't return a mask of interrupts from probe_irq_on, |
| * but return the number of interrupts enabled for the probe. |
| * The interrupts which have been enabled for probing is |
| * instead recorded in the irq_desc structure. |
| */ |
| unsigned long probe_irq_on(void) |
| { |
| unsigned int i, irqs = 0; |
| unsigned long delay; |
| |
| /* |
| * first snaffle up any unassigned but |
| * probe-able interrupts |
| */ |
| spin_lock_irq(&irq_controller_lock); |
| for (i = 0; i < NR_IRQS; i++) { |
| if (!irq_desc[i].probe_ok || irq_desc[i].action) |
| continue; |
| |
| irq_desc[i].probing = 1; |
| irq_desc[i].triggered = 0; |
| if (irq_desc[i].chip->type) |
| irq_desc[i].chip->type(i, IRQT_PROBE); |
| irq_desc[i].chip->unmask(i); |
| irqs += 1; |
| } |
| spin_unlock_irq(&irq_controller_lock); |
| |
| /* |
| * wait for spurious interrupts to mask themselves out again |
| */ |
| for (delay = jiffies + HZ/10; time_before(jiffies, delay); ) |
| /* min 100ms delay */; |
| |
| /* |
| * now filter out any obviously spurious interrupts |
| */ |
| spin_lock_irq(&irq_controller_lock); |
| for (i = 0; i < NR_IRQS; i++) { |
| if (irq_desc[i].probing && irq_desc[i].triggered) { |
| irq_desc[i].probing = 0; |
| irqs -= 1; |
| } |
| } |
| spin_unlock_irq(&irq_controller_lock); |
| |
| return irqs; |
| } |
| |
| EXPORT_SYMBOL(probe_irq_on); |
| |
| /* |
| * Possible return values: |
| * >= 0 - interrupt number |
| * -1 - no interrupt/many interrupts |
| */ |
| int probe_irq_off(unsigned long irqs) |
| { |
| unsigned int i; |
| int irq_found = NO_IRQ; |
| |
| /* |
| * look at the interrupts, and find exactly one |
| * that we were probing has been triggered |
| */ |
| spin_lock_irq(&irq_controller_lock); |
| for (i = 0; i < NR_IRQS; i++) { |
| if (irq_desc[i].probing && |
| irq_desc[i].triggered) { |
| if (irq_found != NO_IRQ) { |
| irq_found = NO_IRQ; |
| goto out; |
| } |
| irq_found = i; |
| } |
| } |
| |
| if (irq_found == -1) |
| irq_found = NO_IRQ; |
| out: |
| spin_unlock_irq(&irq_controller_lock); |
| |
| return irq_found; |
| } |
| |
| EXPORT_SYMBOL(probe_irq_off); |
| |
| void __init init_irq_proc(void) |
| { |
| } |
| |
| void __init init_IRQ(void) |
| { |
| struct irqdesc *desc; |
| extern void init_dma(void); |
| int irq; |
| |
| for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) |
| *desc = bad_irq_desc; |
| |
| arc_init_irq(); |
| init_dma(); |
| } |