1 files changed, 123 insertions, 0 deletions
diff --git a/linux/src/drivers/net/auto_irq.c b/linux/src/drivers/net/auto_irq.c
new file mode 100644
index 00000000..82bc7b1c
--- /dev/null
+++ b/linux/src/drivers/net/auto_irq.c
@@ -0,0 +1,123 @@
+/* auto_irq.c: Auto-configure IRQ lines for linux. */
+/*
+    Written 1994 by Donald Becker.
+
+    The author may be reached as becker@CESDIS.gsfc.nasa.gov, or C/O
+    Center of Excellence in Space Data and Information Sciences
+      Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771
+
+    This code is a general-purpose IRQ line detector for devices with
+    jumpered IRQ lines.  If you can make the device raise an IRQ (and
+    that IRQ line isn't already being used), these routines will tell
+    you what IRQ line it's using -- perfect for those oh-so-cool boot-time
+    device probes!
+
+    To use this, first call autoirq_setup(timeout). TIMEOUT is how many
+    'jiffies' (1/100 sec.) to detect other devices that have active IRQ lines,
+    and can usually be zero at boot.  'autoirq_setup()' returns the bit
+    vector of nominally-available IRQ lines (lines may be physically in-use,
+    but not yet registered to a device).
+    Next, set up your device to trigger an interrupt.
+    Finally call autoirq_report(TIMEOUT) to find out which IRQ line was
+    most recently active.  The TIMEOUT should usually be zero, but may
+    be set to the number of jiffies to wait for a slow device to raise an IRQ.
+
+    The idea of using the setup timeout to filter out bogus IRQs came from
+    the serial driver.
+*/
+
+
+#ifdef version
+static const char *version=
+"auto_irq.c:v1.11 Donald Becker (becker@cesdis.gsfc.nasa.gov)";
+#endif
+
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <asm/bitops.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <linux/netdevice.h>
+
+struct device *irq2dev_map[NR_IRQS] = {0, 0, /* ... zeroed */};
+
+unsigned long irqs_busy = 0x2147;		/* The set of fixed IRQs (keyboard, timer, etc) */
+unsigned long irqs_used = 0x0001;		/* The set of fixed IRQs sometimes enabled. */
+unsigned long irqs_reserved = 0x0000;		/* An advisory "reserved" table. */
+unsigned long irqs_shared = 0x0000;		/* IRQ lines "shared" among conforming cards.*/
+
+static volatile unsigned long irq_bitmap;	/* The irqs we actually found. */
+static unsigned long irq_handled;		/* The irq lines we have a handler on. */
+static volatile int irq_number;			/* The latest irq number we actually found. */
+
+static void autoirq_probe(int irq, void *dev_id, struct pt_regs * regs)
+{
+	irq_number = irq;
+	set_bit(irq, (void *)&irq_bitmap);	/* irq_bitmap |= 1 << irq; */
+	/* This code used to disable the irq. However, the interrupt stub
+	 * would then re-enable the interrupt with (potentially) disastrous
+	 * consequences
+	 */
+	free_irq(irq, dev_id);
+	return;
+}
+
+int autoirq_setup(int waittime)
+{
+	int i;
+	unsigned long timeout = jiffies + waittime;
+	unsigned long boguscount = (waittime*loops_per_sec) / 100;
+
+	irq_handled = 0;
+	irq_bitmap = 0;
+
+	for (i = 0; i < 16; i++) {
+		if (test_bit(i, &irqs_busy) == 0
+			&& request_irq(i, autoirq_probe, SA_INTERRUPT, "irq probe", NULL) == 0)
+			set_bit(i, (void *)&irq_handled);	/* irq_handled |= 1 << i;*/
+	}
+	/* Update our USED lists. */
+	irqs_used |= ~irq_handled;
+
+	/* Hang out at least <waittime> jiffies waiting for bogus IRQ hits. */
+	while (timeout > jiffies  &&  --boguscount > 0)
+		;
+
+	irq_handled &= ~irq_bitmap;
+
+	irq_number = 0;	/* We are interested in new interrupts from now on */
+
+	return irq_handled;
+}
+
+int autoirq_report(int waittime)
+{
+	int i;
+	unsigned long timeout = jiffies+waittime;
+	unsigned long boguscount = (waittime*loops_per_sec) / 100;
+
+	/* Hang out at least <waittime> jiffies waiting for the IRQ. */
+
+	while (timeout > jiffies  &&  --boguscount > 0)
+		if (irq_number)
+			break;
+
+	irq_handled &= ~irq_bitmap;	/* This eliminates the already reset handlers */
+
+	/* Retract the irq handlers that we installed. */
+	for (i = 0; i < 16; i++) {
+		if (test_bit(i, (void *)&irq_handled))
+			free_irq(i, NULL);
+	}
+	return irq_number;
+}
+
+/*
+ * Local variables:
+ *  compile-command: "gcc -DKERNEL -Wall -O6 -fomit-frame-pointer -I/usr/src/linux/net/tcp -c auto_irq.c"
+ *  version-control: t
+ *  kept-new-versions: 5
+ *  c-indent-level: 4
+ *  tab-width: 4
+ * End:
+ */