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Diffstat (limited to 'linux/src/drivers/net/auto_irq.c')
-rw-r--r-- | linux/src/drivers/net/auto_irq.c | 123 |
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 0000000..82bc7b1 --- /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: + */ |