drivers/net/auto

/* */
This source file includes following definitions.
autoirq_probe
autoirq_setup
autoirq_report
   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/sched.h>
  36 #include <linux/delay.h>
  37 #include <asm/bitops.h>
  38 #include <asm/io.h>
  39 #include <asm/irq.h>
  40 #include <linux/netdevice.h>
  41 
  42 struct device *irq2dev_map[16] = {0, 0, /* ... zeroed */};
  43 
  44 unsigned long irqs_busy = 0x2147;               /* The set of fixed IRQs (keyboard, timer, etc) */
  45 unsigned long irqs_used = 0x0001;               /* The set of fixed IRQs sometimes enabled. */
  46 unsigned long irqs_reserved = 0x0000;           /* An advisory "reserved" table. */
  47 unsigned long irqs_shared = 0x0000;             /* IRQ lines "shared" among conforming cards.*/
  48 
  49 static volatile unsigned long irq_bitmap;       /* The irqs we actually found. */
  50 static unsigned long irq_handled;               /* The irq lines we have a handler on. */
  51 static volatile int irq_number;                 /* The latest irq number we actually found. */
  52 
  53 static void autoirq_probe(int irq, void *dev_id, struct pt_regs * regs)
     /*  */
  54 {
  55         irq_number = irq;
  56         set_bit(irq, (void *)&irq_bitmap);      /* irq_bitmap |= 1 << irq; */
  57         disable_irq(irq);
  58         return;
  59 }
  60 
  61 int autoirq_setup(int waittime)
     /*  */
  62 {
  63         int i, mask;
  64         int timeout = jiffies + waittime;
  65         int boguscount = (waittime*loops_per_sec) / 100;
  66 
  67         irq_handled = 0;
  68         for (i = 0; i < 16; i++) {
  69                 if (test_bit(i, &irqs_busy) == 0
  70                         && request_irq(i, autoirq_probe, SA_INTERRUPT, "irq probe", NULL) == 0)
  71                         set_bit(i, (void *)&irq_handled);       /* irq_handled |= 1 << i;*/
  72         }
  73         /* Update our USED lists. */
  74         irqs_used |= ~irq_handled;
  75         irq_number = 0;
  76         irq_bitmap = 0;
  77 
  78         /* Hang out at least <waittime> jiffies waiting for bogus IRQ hits. */
  79         while (timeout > jiffies  &&  --boguscount > 0)
  80                 ;
  81 
  82         for (i = 0, mask = 0x01; i < 16; i++, mask <<= 1) {
  83                 if (irq_bitmap & irq_handled & mask) {
  84                         irq_handled &= ~mask;
  85 #ifdef notdef
  86                         printk(" Spurious interrupt on IRQ %d\n", i);
  87 #endif
  88                         free_irq(i, NULL);
  89                 }
  90         }
  91         return irq_handled;
  92 }
  93 
  94 int autoirq_report(int waittime)
     /*  */
  95 {
  96         int i;
  97         int timeout = jiffies+waittime;
  98         int boguscount = (waittime*loops_per_sec) / 100;
  99 
 100         /* Hang out at least <waittime> jiffies waiting for the IRQ. */
 101 
 102         while (timeout > jiffies  &&  --boguscount > 0)
 103                 if (irq_number)
 104                         break;
 105 
 106         /* Retract the irq handlers that we installed. */
 107         for (i = 0; i < 16; i++) {
 108                 if (test_bit(i, (void *)&irq_handled))
 109                         free_irq(i, NULL);
 110         }
 111         return irq_number;
 112 }
 113 
 114 /*
 115  * Local variables:
 116  *  compile-command: "gcc -DKERNEL -Wall -O6 -fomit-frame-pointer -I/usr/src/linux/net/tcp -c auto_irq.c"
 117  *  version-control: t
 118  *  kept-new-versions: 5
 119  *  c-indent-level: 4
 120  *  tab-width: 4
 121  * End:
 122  */
/* */
root/drivers/net/auto_irq.c

DEFINITIONS
