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

1.1     ! root        1: /*
        !             2:  * Linux I/O port management.
        !             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: #include <linux/ioport.h>
        !            21: 
        !            22: #define NPORTS         65536
        !            23: #define BITS_PER_WORD  32
        !            24: #define NWORDS         (NPORTS / BITS_PER_WORD)
        !            25: 
        !            26: /*
        !            27:  * This bitmap keeps track of all allocated ports.
        !            28:  * A bit is set if the port has been allocated.
        !            29:  */
        !            30: static unsigned port_bitmap[NWORDS];
        !            31: 
        !            32: void snarf_region(unsigned, unsigned);
        !            33: 
        !            34: /*
        !            35:  * Check if a region is available for use.
        !            36:  */
        !            37: int
        !            38: check_region(unsigned port, unsigned size)
        !            39: {
        !            40:        unsigned i;
        !            41: 
        !            42:        for (i = port; i < port + size; i++)
        !            43:                if (port_bitmap[i/BITS_PER_WORD] & (1 << (i%BITS_PER_WORD)))
        !            44:                        return (1);
        !            45:        return (0);
        !            46: }
        !            47: 
        !            48: /*
        !            49:  * Allocate a region.
        !            50:  */
        !            51: void
        !            52: request_region(unsigned port, unsigned size, const char *name)
        !            53: {
        !            54:        unsigned i;
        !            55: 
        !            56:        for (i = port; i < port + size; i++)
        !            57:                port_bitmap[i / BITS_PER_WORD] |= 1 << (i % BITS_PER_WORD);
        !            58: }
        !            59: 
        !            60: /*
        !            61:  * For compatibility with older kernels.
        !            62:  */
        !            63: void
        !            64: snarf_region(unsigned port, unsigned size)
        !            65: {
        !            66:        request_region(port, size, 0);
        !            67: }
        !            68: 
        !            69: /*
        !            70:  * Deallocate a region.
        !            71:  */
        !            72: void
        !            73: release_region(unsigned port, unsigned size)
        !            74: {
        !            75:        unsigned i;
        !            76: 
        !            77:        for (i = port; i < port + size; i++)
        !            78:                port_bitmap[i / BITS_PER_WORD] &= ~(1 << (i % BITS_PER_WORD));
        !            79: }

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