lambdrv.c

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/* lambDrv.c - simple (baby) ram disk driver */

#include "vxWorks.h"
#include "blkIo.h"
#include "ioLib.h"
#include "iosLib.h"
#include "memLib.h"

#define BLK_SIZE	512

typedef struct		/* LAMB_DEV - ram disk device descriptor */
    {
    BLK_DEV	 lamb_blkdev;	/* generic block device structure */
    char	 *lamb_addr;	/* memory location of the ram disk */
    } LAMB_DEV;



/* FORWARD DECLARATIONS */

LOCAL STATUS lambIoctl ();
LOCAL STATUS lambBlkRd ();
LOCAL STATUS lambBlkWrt ();


STATUS lambDrv ()

    {
    return (OK);			/* no initialization required */
    }


BLK_DEV *lambDevCreate (nBlocks)
    int			nBlocks;	/* Number of blocks on this device */

    {
    FAST LAMB_DEV	*pLambDev;	/* ptr to created LAMB_DEV struct */
    FAST BLK_DEV	*pBlkDev;	/* ptr to BLK_DEV struct in LAMB_DEV */


    /* Set up defaults for any values not specified */

    if (nBlocks == 0)
		return (NULL);


    /* Allocate a LAMB_DEV structure for device */

    pLambDev = (LAMB_DEV *) malloc (sizeof (LAMB_DEV));
    if (pLambDev == NULL)
		return (NULL);					/* no memory */


    /* Initialize BLK_DEV structure (in LAMB_DEV) */

    pBlkDev = &pLambDev->lamb_blkdev;

    pBlkDev->bd_nBlocks      = nBlocks;		/* number of blocks */
    pBlkDev->bd_bytesPerBlk  = BLK_SIZE;	/* bytes per block */
    pBlkDev->bd_blksPerTrack = nBlocks;	/* blocks per track */

    pBlkDev->bd_nHeads       = 1;		/* one "head" */
    pBlkDev->bd_removable    = FALSE;		/* not removable */
    pBlkDev->bd_retry	     = 0;		/* retry count */
    pBlkDev->bd_mode	     = UPDATE;		/* initial mode for device */
    pBlkDev->bd_readyChanged = TRUE;		/* new ready status */

    pBlkDev->bd_blkRd	     = lambBlkRd;	/* read block function */
    pBlkDev->bd_blkWrt	     = lambBlkWrt;	/* write block function */
    pBlkDev->bd_ioctl	     = lambIoctl;	/* ioctl function */
    pBlkDev->bd_reset	     = NULL;		/* no reset function */
    pBlkDev->bd_statusChk    = NULL;		/* no check-status function */


    /* Initialize remainder of device struct */

	pLambDev->lamb_addr = (char *) malloc ((UINT) (BLK_SIZE * nBlocks));

	if (pLambDev->lamb_addr == NULL)
	    {
	    free ((char *) pLambDev);
	    return (NULL);				/* no memory */
	    }

    return (&pLambDev->lamb_blkdev);
    }


LOCAL STATUS lambIoctl (pLambDev, function, arg)
    LAMB_DEV	*pLambDev;		/* device structure pointer */
    int		function;		/* function code */
    int		arg;			/* some argument */

    {
    FAST int	status;			/* returned status value */


    switch (function)
	{
	case FIODISKFORMAT:
	    status = OK;
	    break;

	default:
	    errnoSet (S_ioLib_UNKNOWN_REQUEST);
	    status = ERROR;
	}

    return (status);
    }


LOCAL STATUS lambBlkRd (pLambDev, startBlk, numBlks, pBuffer)
    FAST LAMB_DEV	*pLambDev;	/* pointer to device desriptor */
    int			startBlk;	/* starting block number to read */
    int			numBlks;	/* number of blocks to read */
    char		*pBuffer;	/* pointer to buffer to receive data */

    {

    /* Read the block(s) */

    bcopy ((pLambDev->lamb_addr + (startBlk * BLK_SIZE)), pBuffer, 
	   BLK_SIZE * numBlks);

    return (OK);
    }


LOCAL STATUS lambBlkWrt (pLambDev, startBlk, numBlks, pBuffer)
    FAST LAMB_DEV	*pLambDev;	/* pointer to device desriptor */
    int			startBlk;	/* starting block number to write */
    int			numBlks;	/* number of blocks to write */
    char		*pBuffer;	/* pointer to buffer of data to write */

    {

    /* Write the block(s) */

    bcopy (pBuffer, (pLambDev->lamb_addr + (startBlk * BLK_SIZE)),
	   BLK_SIZE * numBlks);

    return (OK);
    }