1 /* auto_irq.c: Auto-configure IRQ lines for linux. */
2 /*
3 Written 1994 by Donald Becker.
4
5 The author may be reached as becker@CESDIS.gsfc.nasa.gov, or C/O
6 Center of Excellence in Space Data and Information Sciences
7 Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771
8
9 This code is a general-purpose IRQ line detector for devices with
10 jumpered IRQ lines. If you can make the device raise an IRQ (and
11 that IRQ line isn't already being used), these routines will tell
12 you what IRQ line it's using -- perfect for those oh-so-cool boot-time
13 device probes!
14
15 To use this, first call autoirq_setup(timeout). TIMEOUT is how many
16 'jiffies' (1/100 sec.) to detect other devices that have active IRQ lines,
17 and can usually be zero at boot. 'autoirq_setup()' returns the bit
18 vector of nominally-available IRQ lines (lines may be physically in-use,
19 but not yet registered to a device).
20 Next, set up your device to trigger an interrupt.
21 Finally call autoirq_report(TIMEOUT) to find out which IRQ line was
22 most recently active. The TIMEOUT should usually be zero, but may
23 be set to the number of jiffies to wait for a slow device to raise an IRQ.
24
25 The idea of using the setup timeout to filter out bogus IRQs came from
26 the serial driver.
27 */
28
29
30 #ifdef version
31 static const char *version=
32 "auto_irq.c:v1.11 Donald Becker (becker@cesdis.gsfc.nasa.gov)";
33 #endif
34
35 #include <linux/module.h>
36 #include <linux/sched.h>
37 #include <linux/delay.h>
38 #include <asm/bitops.h>
39 #include <asm/io.h>
40 #include <asm/irq.h>
41 #include <linux/netdevice.h>
42
43 static unsigned long irqs;
44
45 void autoirq_setup(int waittime)
46 {
47 irqs = probe_irq_on();
48 }
49
50 #define BUSY_LOOP_UNTIL(j) while ((long)(jiffies-(j)) < 0) ;
51 int autoirq_report(int waittime)
52 {
53 unsigned long delay = jiffies + waittime;
54 BUSY_LOOP_UNTIL(delay)
55 return probe_irq_off(irqs);
56 }
57
58 EXPORT_SYMBOL(autoirq_setup);
59 EXPORT_SYMBOL(autoirq_report);
60
61
62 /*
63 * Local variables:
64 * compile-command: "gcc -DKERNEL -Wall -O6 -fomit-frame-pointer -I/usr/src/linux/net/tcp -c auto_irq.c"
65 * version-control: t
66 * kept-new-versions: 5
67 * c-indent-level: 4
68 * tab-width: 4
69 * End:
70 */
71
This page was automatically generated by the
LXR engine.
Visit the LXR main site for more
information.