Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 189 insertions, 0 deletions

diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c
new file mode 100644
index 000000000000..98d62d8efeaf
--- /dev/null
+++ b/kernel/irq/autoprobe.c
@@ -0,0 +1,189 @@
+/*
+ * linux/kernel/irq/autoprobe.c
+ *
+ * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
+ *
+ * This file contains the interrupt probing code and driver APIs.
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+
+/*
+ * Autodetection depends on the fact that any interrupt that
+ * comes in on to an unassigned handler will get stuck with
+ * "IRQ_WAITING" cleared and the interrupt disabled.
+ */
+static DECLARE_MUTEX(probe_sem);
+
+/**
+ *      probe_irq_on    - begin an interrupt autodetect
+ *
+ *      Commence probing for an interrupt. The interrupts are scanned
+ *      and a mask of potential interrupt lines is returned.
+ *
+ */
+unsigned long probe_irq_on(void)
+{
+        unsigned long val, delay;
+        irq_desc_t *desc;
+        unsigned int i;
+
+        down(&probe_sem);
+        /*
+         * something may have generated an irq long ago and we want to
+         * flush such a longstanding irq before considering it as spurious.
+         */
+        for (i = NR_IRQS-1; i > 0; i--) {
+                desc = irq_desc + i;
+
+                spin_lock_irq(&desc->lock);
+                if (!irq_desc[i].action)
+                        irq_desc[i].handler->startup(i);
+                spin_unlock_irq(&desc->lock);
+        }
+
+        /* Wait for longstanding interrupts to trigger. */
+        for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
+                /* about 20ms delay */ barrier();
+
+        /*
+         * enable any unassigned irqs
+         * (we must startup again here because if a longstanding irq
+         * happened in the previous stage, it may have masked itself)
+         */
+        for (i = NR_IRQS-1; i > 0; i--) {
+                desc = irq_desc + i;
+
+                spin_lock_irq(&desc->lock);
+                if (!desc->action) {
+                        desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
+                        if (desc->handler->startup(i))
+                                desc->status |= IRQ_PENDING;
+                }
+                spin_unlock_irq(&desc->lock);
+        }
+
+        /*
+         * Wait for spurious interrupts to trigger
+         */
+        for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
+                /* about 100ms delay */ barrier();
+
+        /*
+         * Now filter out any obviously spurious interrupts
+         */
+        val = 0;
+        for (i = 0; i < NR_IRQS; i++) {
+                irq_desc_t *desc = irq_desc + i;
+                unsigned int status;
+
+                spin_lock_irq(&desc->lock);
+                status = desc->status;
+
+                if (status & IRQ_AUTODETECT) {
+                        /* It triggered already - consider it spurious. */
+                        if (!(status & IRQ_WAITING)) {
+                                desc->status = status & ~IRQ_AUTODETECT;
+                                desc->handler->shutdown(i);
+                        } else
+                                if (i < 32)
+                                        val |= 1 << i;
+                }
+                spin_unlock_irq(&desc->lock);
+        }
+
+        return val;
+}
+
+EXPORT_SYMBOL(probe_irq_on);
+
+/**
+ *      probe_irq_mask - scan a bitmap of interrupt lines
+ *      @val:   mask of interrupts to consider
+ *
+ *      Scan the interrupt lines and return a bitmap of active
+ *      autodetect interrupts. The interrupt probe logic state
+ *      is then returned to its previous value.
+ *
+ *      Note: we need to scan all the irq's even though we will
+ *      only return autodetect irq numbers - just so that we reset
+ *      them all to a known state.
+ */
+unsigned int probe_irq_mask(unsigned long val)
+{
+        unsigned int mask;
+        int i;
+
+        mask = 0;
+        for (i = 0; i < NR_IRQS; i++) {
+                irq_desc_t *desc = irq_desc + i;
+                unsigned int status;
+
+                spin_lock_irq(&desc->lock);
+                status = desc->status;
+
+                if (status & IRQ_AUTODETECT) {
+                        if (i < 16 && !(status & IRQ_WAITING))
+                                mask |= 1 << i;
+
+                        desc->status = status & ~IRQ_AUTODETECT;
+                        desc->handler->shutdown(i);
+                }
+                spin_unlock_irq(&desc->lock);
+        }
+        up(&probe_sem);
+
+        return mask & val;
+}
+EXPORT_SYMBOL(probe_irq_mask);
+
+/**
+ *      probe_irq_off   - end an interrupt autodetect
+ *      @val: mask of potential interrupts (unused)
+ *
+ *      Scans the unused interrupt lines and returns the line which
+ *      appears to have triggered the interrupt. If no interrupt was
+ *      found then zero is returned. If more than one interrupt is
+ *      found then minus the first candidate is returned to indicate
+ *      their is doubt.
+ *
+ *      The interrupt probe logic state is returned to its previous
+ *      value.
+ *
+ *      BUGS: When used in a module (which arguably shouldn't happen)
+ *      nothing prevents two IRQ probe callers from overlapping. The
+ *      results of this are non-optimal.
+ */
+int probe_irq_off(unsigned long val)
+{
+        int i, irq_found = 0, nr_irqs = 0;
+
+        for (i = 0; i < NR_IRQS; i++) {
+                irq_desc_t *desc = irq_desc + i;
+                unsigned int status;
+
+                spin_lock_irq(&desc->lock);
+                status = desc->status;
+
+                if (status & IRQ_AUTODETECT) {
+                        if (!(status & IRQ_WAITING)) {
+                                if (!nr_irqs)
+                                        irq_found = i;
+                                nr_irqs++;
+                        }
+                        desc->status = status & ~IRQ_AUTODETECT;
+                        desc->handler->shutdown(i);
+                }
+                spin_unlock_irq(&desc->lock);
+        }
+        up(&probe_sem);
+
+        if (nr_irqs > 1)
+                irq_found = -irq_found;
+        return irq_found;
+}
+
+EXPORT_SYMBOL(probe_irq_off);
+