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

1.1     ! root        1: /*
        !             2:  * Linux DMA channel 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: #define MACH_INCLUDE
        !            21: #include <linux/errno.h>
        !            22: #include <asm/dma.h>
        !            23: 
        !            24: /*
        !            25:  * Bitmap of allocated/free DMA channels.
        !            26:  */
        !            27: static int dma_busy = 0x10;
        !            28: 
        !            29: /*
        !            30:  * Allocate a DMA channel.
        !            31:  */
        !            32: int
        !            33: request_dma(unsigned int drq, const char *name)
        !            34: {
        !            35:        if (drq > 7)
        !            36:                panic("request_dma: bad DRQ number");
        !            37:        if (dma_busy & (1 << drq))
        !            38:                return (-LINUX_EBUSY);
        !            39:        dma_busy |= 1 << drq;
        !            40:        return (0);
        !            41: }
        !            42: 
        !            43: /*
        !            44:  * Free a DMA channel.
        !            45:  */
        !            46: void
        !            47: free_dma(unsigned int drq)
        !            48: {
        !            49:        if (drq > 7)
        !            50:                panic("free_dma: bad DRQ number");
        !            51:        dma_busy &= ~(1 << drq);
        !            52: }

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