aboutsummaryrefslogtreecommitdiff
path: root/arch/m68k/hp300/ints.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/m68k/hp300/ints.c')
-rw-r--r--arch/m68k/hp300/ints.c175
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);
+}