diff options
Diffstat (limited to 'arch/m68k/hp300/ints.c')
| -rw-r--r-- | arch/m68k/hp300/ints.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/arch/m68k/hp300/ints.c b/arch/m68k/hp300/ints.c new file mode 100644 index 000000000000..0c5bb403e893 --- /dev/null +++ b/arch/m68k/hp300/ints.c @@ -0,0 +1,175 @@ +/* + * linux/arch/m68k/hp300/ints.c + * + * Copyright (C) 1998 Philip Blundell <philb@gnu.org> + * + * This file contains the HP300-specific interrupt handling. + * We only use the autovector interrupts, and therefore we need to + * maintain lists of devices sharing each ipl. + * [ipl list code added by Peter Maydell <pmaydell@chiark.greenend.org.uk> 06/1998] + */ + +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/kernel_stat.h> +#include <linux/interrupt.h> +#include <linux/spinlock.h> +#include <asm/machdep.h> +#include <asm/irq.h> +#include <asm/io.h> +#include <asm/system.h> +#include <asm/traps.h> +#include <asm/ptrace.h> +#include <asm/errno.h> +#include "ints.h" + +/* Each ipl has a linked list of interrupt service routines. + * Service routines are added via hp300_request_irq() and removed + * via hp300_free_irq(). The device driver should set IRQ_FLG_FAST + * if it needs to be serviced early (eg FIFOless UARTs); this will + * cause it to be added at the front of the queue rather than + * the back. + * Currently IRQ_FLG_SLOW and flags=0 are treated identically; if + * we needed three levels of priority we could distinguish them + * but this strikes me as mildly ugly... + */ + +/* we start with no entries in any list */ +static irq_node_t *hp300_irq_list[HP300_NUM_IRQS]; + +static spinlock_t irqlist_lock; + +/* This handler receives all interrupts, dispatching them to the registered handlers */ +static irqreturn_t hp300_int_handler(int irq, void *dev_id, struct pt_regs *fp) +{ + irq_node_t *t; + /* We just give every handler on the chain an opportunity to handle + * the interrupt, in priority order. + */ + for(t = hp300_irq_list[irq]; t; t=t->next) + t->handler(irq, t->dev_id, fp); + /* We could put in some accounting routines, checks for stray interrupts, + * etc, in here. Note that currently we can't tell whether or not + * a handler handles the interrupt, though. + */ + return IRQ_HANDLED; +} + +static irqreturn_t hp300_badint(int irq, void *dev_id, struct pt_regs *fp) +{ + num_spurious += 1; + return IRQ_NONE; +} + +irqreturn_t (*hp300_default_handler[SYS_IRQS])(int, void *, struct pt_regs *) = { + [0] = hp300_badint, + [1] = hp300_int_handler, + [2] = hp300_int_handler, + [3] = hp300_int_handler, + [4] = hp300_int_handler, + [5] = hp300_int_handler, + [6] = hp300_int_handler, + [7] = hp300_int_handler +}; + +/* dev_id had better be unique to each handler because it's the only way we have + * to distinguish handlers when removing them... + * + * It would be pretty easy to support IRQ_FLG_LOCK (handler is not replacable) + * and IRQ_FLG_REPLACE (handler replaces existing one with this dev_id) + * if we wanted to. IRQ_FLG_FAST is needed for devices where interrupt latency + * matters (eg the dreaded FIFOless UART...) + */ +int hp300_request_irq(unsigned int irq, + irqreturn_t (*handler) (int, void *, struct pt_regs *), + unsigned long flags, const char *devname, void *dev_id) +{ + irq_node_t *t, *n = new_irq_node(); + + if (!n) /* oops, no free nodes */ + return -ENOMEM; + + spin_lock_irqsave(&irqlist_lock, flags); + + if (!hp300_irq_list[irq]) { + /* no list yet */ + hp300_irq_list[irq] = n; + n->next = NULL; + } else if (flags & IRQ_FLG_FAST) { + /* insert at head of list */ + n->next = hp300_irq_list[irq]; + hp300_irq_list[irq] = n; + } else { + /* insert at end of list */ + for(t = hp300_irq_list[irq]; t->next; t = t->next) + /* do nothing */; + n->next = NULL; + t->next = n; + } + + /* Fill in n appropriately */ + n->handler = handler; + n->flags = flags; + n->dev_id = dev_id; + n->devname = devname; + spin_unlock_irqrestore(&irqlist_lock, flags); + return 0; +} + +void hp300_free_irq(unsigned int irq, void *dev_id) +{ + irq_node_t *t; + unsigned long flags; + + spin_lock_irqsave(&irqlist_lock, flags); + + t = hp300_irq_list[irq]; + if (!t) /* no handlers at all for that IRQ */ + { + printk(KERN_ERR "hp300_free_irq: attempt to remove nonexistent handler for IRQ %d\n", irq); + spin_unlock_irqrestore(&irqlist_lock, flags); + return; + } + + if (t->dev_id == dev_id) + { /* removing first handler on chain */ + t->flags = IRQ_FLG_STD; /* we probably don't really need these */ + t->dev_id = NULL; + t->devname = NULL; + t->handler = NULL; /* frees this irq_node_t */ + hp300_irq_list[irq] = t->next; + spin_unlock_irqrestore(&irqlist_lock, flags); + return; + } + + /* OK, must be removing from middle of the chain */ + + for (t = hp300_irq_list[irq]; t->next && t->next->dev_id != dev_id; t = t->next) + /* do nothing */; + if (!t->next) + { + printk(KERN_ERR "hp300_free_irq: attempt to remove nonexistent handler for IRQ %d\n", irq); + spin_unlock_irqrestore(&irqlist_lock, flags); + return; + } + /* remove the entry after t: */ + t->next->flags = IRQ_FLG_STD; + t->next->dev_id = NULL; + t->next->devname = NULL; + t->next->handler = NULL; + t->next = t->next->next; + + spin_unlock_irqrestore(&irqlist_lock, flags); +} + +int show_hp300_interrupts(struct seq_file *p, void *v) +{ + return 0; +} + +void __init hp300_init_IRQ(void) +{ + spin_lock_init(&irqlist_lock); +} |