pdma_func.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static	char	*sccsid = "@(#)pdma_func.c	4.1	(ULTRIX)	9/11/90";
#endif lint

/************************************************************************
 *									*
 *			Copyright (c) 1988 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
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 *   software  or  any	other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
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 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or	reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *
 * pdma_func.c	10/25/89
 *
 * Pseudo DMA routines for all systems.
 *
 * Modification History:
 *
 * 09/07/90     Maria Vella
 * Submitted this file to release.
 *
 * 10/11/89	John A. Gallant
 * Created this file to support the PDMA work in the scsi drivers.
 *
 * 10/25/89	John A. Gallant
 * Added the pdma_flush() entry in the function copy area.
 *
 ************************************************************************/

/* This file contains the Pseudo DMA routines needed for all the PDMA
systems. */

#include "../data/scsi_data.c"
#include "scsi_debug.h"

/* External functions and variables. */

extern PDMA_ENTRY *pdma_entry[];		/* the entry array */


/* Global DMA independent Routines needed: */

/************************************************************************

int pdma_attach( sc, cputype )

Inputs:	sz_softc pointer
	cputype value

Function:   Using the cputype argument, scan the PDMA entry array to find
	    a match for the cputype.  When a match is found, the pdma_func()
	    pointers in the softc struct will be filled with the pointers 
	    from the PDMA entry array.  Once the softc struct is set the
	    pdma_init() routine will be called.

Return:	The return value from the pdma_init() will be returned to the caller.
	In the event that no match is made with in the PDMA entry array,
	failure will be returned.

*************************************************************************/

int pdma_attach( sc, cputype )
    struct sz_softc *sc;
    int cputype;
{
    PDMA_ENTRY *pe;		/* for accessing the entries in the array */
    int i;			/* local loop control variable */

    PRINTD( 0xFF, 0x401, ("pdma_attach entry cputype %d\n", cputype ));

    /* Within a loop scan the PDMA_ENTRY array looking for a match to the 
    cputype in the type field.  */

    for( i = 0; ; i++ )
    {
	pe = pdma_entry[ i ];		/* assign the pointer */

      /* If the entry is not defined, we have reached the end of the array.
	Return FAILURE to the caller and hope he knows what to do with it. */

	if( pe == NULL )
	{
	    PRINTD( 0xFF, 0x411, ("pdma_attach no entry match found\n"));
	    return( PDMA_ALLOC_FAIL );	/* signal no match */
	}

        /* If the cputypes match, setup the pointers and call init routine. */

	if( pe->pdma_cputype == cputype )
	{
	    PRINTD( 0xFF, 0x402, ("pdma_attach match found pe: %x\n", pe ));
	    sc->dma_init   = pe->pdma_init;
	    sc->dma_setup  = pe->pdma_setup;
	    sc->dma_start  = pe->pdma_start;
	    sc->dma_cont   = pe->pdma_cont;
	    sc->dma_end    = pe->pdma_end;
	    sc->dma_rbcopy = pe->pdma_rbcopy;
	    sc->dma_wbcopy = pe->pdma_wbcopy;
	    sc->dma_bzero  = pe->pdma_bzero;
	    sc->dma_flush  = pe->pdma_flush;
	    sc->dma_pflags = pe->pdma_pflags;	/* this may not be used */

	    /* Call the init routine, to setup the dma channels etal. */

	    return( (*pe->pdma_init)( sc ) );	/* return what happened */
	}
    }
}

/************************************************************************/