diff options
Diffstat (limited to 'arch/arm26/kernel/irq.c')
| -rw-r--r-- | arch/arm26/kernel/irq.c | 716 |
1 files changed, 716 insertions, 0 deletions
diff --git a/arch/arm26/kernel/irq.c b/arch/arm26/kernel/irq.c new file mode 100644 index 000000000000..f3cc1036e5bc --- /dev/null +++ b/arch/arm26/kernel/irq.c @@ -0,0 +1,716 @@ +/* + * 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/config.h> +#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) + continue; + 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); + } + 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(); +} |