Return to linux_autoirq.c CVS log

Up to [GnuMach] / Gnu-Mach / i386 / i386at / gpl / linux

Annotation of Gnu-Mach/i386/i386at/gpl/linux/linux_autoirq.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Linux auto-irq support.
        !             3:  * Copyright (C) 1995 Shantanu Goel.
        !             4:  *
        !             5:  * This program is free software; you can redistribute it and/or modify
        !             6:  * it under the terms of the GNU General Public License as published by
        !             7:  * the Free Software Foundation; either version 2, or (at your option)
        !             8:  * any later version.
        !             9:  *
        !            10:  * This program is distributed in the hope that it will be useful,
        !            11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            12:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            13:  * GNU General Public License for more details.
        !            14:  *
        !            15:  * You should have received a copy of the GNU General Public License
        !            16:  * along with this program; if not, write to the Free Software
        !            17:  * Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
        !            18:  */
        !            19: 
        !            20: /*
        !            21:  *  Written 1994 by Donald Becker.
        !            22:  *
        !            23:  *  The author may be reached as [email protected], or C/O
        !            24:  *  Center of Excellence in Space Data and Information Sciences
        !            25:  *    Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771
        !            26:  *
        !            27:  *  This code is a general-purpose IRQ line detector for devices with
        !            28:  *  jumpered IRQ lines.  If you can make the device raise an IRQ (and
        !            29:  *  that IRQ line isn't already being used), these routines will tell
        !            30:  *  you what IRQ line it's using -- perfect for those oh-so-cool boot-time
        !            31:  *  device probes!
        !            32:  *
        !            33:  *  To use this, first call autoirq_setup(timeout). TIMEOUT is how many
        !            34:  *  'jiffies' (1/100 sec.) to detect other devices that have active IRQ lines,
        !            35:  *  and can usually be zero at boot.  'autoirq_setup()' returns the bit
        !            36:  *  vector of nominally-available IRQ lines (lines may be physically in-use,
        !            37:  *  but not yet registered to a device).
        !            38:  *  Next, set up your device to trigger an interrupt.
        !            39:  *  Finally call autoirq_report(TIMEOUT) to find out which IRQ line was
        !            40:  *  most recently active.  The TIMEOUT should usually be zero, but may
        !            41:  *  be set to the number of jiffies to wait for a slow device to raise an IRQ.
        !            42:  *
        !            43:  *  The idea of using the setup timeout to filter out bogus IRQs came from
        !            44:  *  the serial driver.
        !            45:  */
        !            46: 
        !            47: #include <i386/pic.h>
        !            48: #include <i386/ipl.h>
        !            49: 
        !            50: #include <linux/sched.h>
        !            51: #include <linux/ptrace.h>
        !            52: 
        !            53: #include <asm/bitops.h>
        !            54: #include <asm/system.h>
        !            55: 
        !            56: /*
        !            57:  * IRQ to network device map.
        !            58:  */
        !            59: void *irq2dev_map[16];
        !            60: 
        !            61: /*
        !            62:  * Set of fixed IRQs
        !            63:  * (fpu, rtc, com1, PIC slave cascade, keyboard, timer).
        !            64:  */
        !            65: int irqs_busy = 0x2147;
        !            66: 
        !            67: static volatile int irq_number;        /* latest irq found */
        !            68: static volatile int irq_bitmap;        /* bitmap of IRQs found */
        !            69: static int irq_handled;                /* irq lines we have a handler on */
        !            70: 
        !            71: extern unsigned long loops_per_sec;
        !            72: 
        !            73: /*
        !            74:  * Interrupt handler when probing an IRQ.
        !            75:  */
        !            76: static void
        !            77: autoirq_probe(irq)
        !            78:        int irq;
        !            79: {
        !            80:        /*
        !            81:         * Mark this IRQ as the last one
        !            82:         * that interrupted and disable it.
        !            83:         */
        !            84:        irq_number = irq;
        !            85:        set_bit(irq, (void *)&irq_bitmap);
        !            86:        disable_irq(irq);
        !            87: }
        !            88: 
        !            89: /*
        !            90:  * Set up for auto-irq.
        !            91:  */
        !            92: int
        !            93: autoirq_setup(waittime)
        !            94:        int waittime;
        !            95: {
        !            96:        int i, mask;
        !            97:        int timeout = jiffies + waittime;
        !            98:        int boguscount = (waittime * loops_per_sec) / 100;
        !            99: 
        !           100:        /*
        !           101:         * Allocate all possible IRQs.
        !           102:         */
        !           103:        irq_handled = 0;
        !           104:        for (i = 0; i < 16; i++) {
        !           105:                if (test_bit(i, (void *)&irqs_busy) == 0
        !           106:                    && request_irq(i, autoirq_probe, 0, 0) == 0)
        !           107:                        set_bit(i, (void *)&irq_handled);
        !           108:        }
        !           109: 
        !           110:        irq_number = 0;
        !           111:        irq_bitmap = 0;
        !           112: 
        !           113:        /*
        !           114:         * Hang out at least <waittime>
        !           115:         * jiffies waiting for bogus IRQ hits.
        !           116:         */
        !           117:        while (timeout > jiffies && --boguscount > 0)
        !           118:                ;
        !           119: 
        !           120:        /*
        !           121:         * Free IRQs that caused bogus hits.
        !           122:         */
        !           123:        for (i = 0, mask = 0x01; i < 16; i++, mask <<= 1) {
        !           124:                if (irq_bitmap & irq_handled & mask) {
        !           125:                        irq_handled &= ~mask;
        !           126:                        free_irq(i);
        !           127:                }
        !           128:        }
        !           129: 
        !           130:        return (irq_handled);
        !           131: }
        !           132: 
        !           133: /*
        !           134:  * Return the last IRQ that caused an interrupt.
        !           135:  */
        !           136: int
        !           137: autoirq_report(waittime)
        !           138:        int waittime;
        !           139: {
        !           140:        int i;
        !           141:        int timeout = jiffies + waittime;
        !           142:        int boguscount = (waittime * loops_per_sec) / 100;
        !           143: 
        !           144:        /*
        !           145:         * Hang out at least <waittime>
        !           146:         * jiffies waiting for the IRQ.
        !           147:         */
        !           148:        while (timeout > jiffies && --boguscount > 0)
        !           149:                if (irq_number)
        !           150:                        break;
        !           151: 
        !           152:        /*
        !           153:         * Retract the IRQ handlers that we handled.
        !           154:         */
        !           155:        for (i = 0; i < 16; i++) {
        !           156:                if (test_bit(i, (void *)&irq_handled))
        !           157:                        free_irq(i);
        !           158:        }
        !           159: 
        !           160:        return (irq_number);
        !           161: }

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.