NeXTSTEP 3.3 (Developer)/NeXT_Developer-3.3.iso/NextDeveloper/Examples/UNIX/SCSI/sg_example.c

C/C++ Source or Header | 1995-02-10 | 4.3 KB | 209 lines

/*
 * Generic SCSI driver example.
 *
 * History
 * -------
 * 02-Feb-93    Erik Kay at NeXT
 *    i386 support
 * 10-Apr-89    Doug Mitchell
 *    Write after read to avoid trashing system disk.
 * 20-Mar-89    Doug Mitchell at NeXT
 *    Created.
 *
 *    Procedure:
 *        open sg0;
 *        set (target,lun) to (1,0);
 *        execute Request Sense command;
 *        Read 4 blocks;
 *        Write 4 blocks;
 *
 *    You may freely copy, distribute and reuse the code in this example.
 *    NeXT disclaims any warranty of any kind, expressed or implied, as to
 *    its fitness for any particular use.
 */

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/types.h>
#include <bsd/dev/scsireg.h>


#define IO_SIZE        4            /* in blocks */
#define BLOCK_SIZE    0x400            /* in bytes */
#define BUF_SIZE    (IO_SIZE*BLOCK_SIZE)
#define SENSE_SIZE    0x40            /* sense buffer size */

char rwbuf[BUF_SIZE];                /* read/write buffer */
char sbuf[SENSE_SIZE];                 /* sense buffer */

int fd;                        /* file descriptor */
int target=1;
int lun=0;
int lba=0;                    /* start block for rd/wr */
char *dev_name="/dev/sg0";

main() {

    struct scsi_adr sa;
    int rtn;
    int i;

    /* open /dev/sg0 */

    if ((fd = open (dev_name, O_RDWR)) < 0) {
        printf("\nCould not open %s - fd = %XH\n",dev_name,fd);
        printf("errno = %d\n",errno);
        perror("open");
        exit(1);
    }

    /* set (target,lun) */

    sa.sa_target = target;
    sa.sa_lun = lun;
    if (ioctl(fd,SGIOCSTL,&sa) < 0) {
        printf("Error setting target %d lun %d\n",target,lun);
        printf("errno = %d\n",errno);
        perror("ioctl(SGIOCSTL)");
        exit(1);
    }

    if(gs_request_sense())            /* clear unit attention */
        exit(1);
    for(i=0; i<BUF_SIZE; i++)        /* init buffer */
        rwbuf[i] = 0;
    if(gs_read(lba,IO_SIZE,rwbuf))        /* read data */
        exit(1);
    if(gs_write(lba,IO_SIZE,rwbuf))        /* write the same data */
        exit(1);

    /* close /dev/sg0 */

    if ((rtn = close(fd)) < 0) {
        printf("\nCould not close %s - fd = %XH\n",dev_name,fd);
        printf("\nerrno = %d\n",errno);
        perror("close");
        exit(1);
    }
    else
        exit(0);

} /* main() */


/*
 *    standard I/O routines
 */

gs_request_sense() {

    struct scsi_req sr;
    struct cdb_6 *cdbp = &sr.sr_cdb.cdb_c6;

    cdb_clr(cdbp);
    cdbp->c6_opcode = C6OP_REQSENSE;
    cdbp->c6_lun    = lun;
    cdbp->c6_len    = SENSE_SIZE;
    sr.sr_dma_dir    = SR_DMA_RD;
    sr.sr_addr    = sbuf;
    sr.sr_dma_max    = SENSE_SIZE;
    sr.sr_ioto    = 10;
    return(do_ioc(&sr));


} /* gs_request_seense() */

gs_read(int lba, int block_count, u_char *bp) {

    /* read block_count blocks starting at lba. Data goes to *bp. */

    struct scsi_req sr;
    struct cdb_6 *cdbp = &sr.sr_cdb.cdb_c6;

    cdb_clr(cdbp);
    cdbp->c6_opcode = C6OP_READ;
    cdbp->c6_lun    = 0;
#ifdef i386
    if (lba > 0) {
        cdbp->c6_lba0 = lba & 0xFF;
        cdbp->c6_lba1 = (lba >> 8) & 0xFF;
        cdbp->c6_lba2 = (lba >> 16) & 0xFF;
    } else
        cdbp->c6_lba0 = cdbp->c6_lba1 = cdbp->c6_lba2 = 0;
#else
    cdbp->c6_lba    = lba;
#endif
    cdbp->c6_len    = block_count;
    sr.sr_dma_dir    = SR_DMA_RD;
    sr.sr_addr    = (char *)bp;
    sr.sr_dma_max    = block_count * BLOCK_SIZE;
    sr.sr_ioto    = 10;
    return(do_ioc(&sr));

} /* gs_read() */

gs_write(int lba, int block_count, u_char *bp) {

    /* write block_count blocks starting at lba. Data comes from *bp. */

    struct scsi_req sr;
    struct cdb_6 *cdbp = &sr.sr_cdb.cdb_c6;

    cdb_clr(cdbp);
    cdbp->c6_opcode = C6OP_WRITE;
    cdbp->c6_lun    = 0;
#ifdef i386
    if (lba > 0) {
        cdbp->c6_lba0 = lba & 0xFF;
        cdbp->c6_lba1 = (lba >> 8) & 0xFF;
        cdbp->c6_lba2 = (lba >> 16) & 0xFF;
    } else
        cdbp->c6_lba0 = cdbp->c6_lba1 = cdbp->c6_lba2 = 0;
#else
    cdbp->c6_lba    = lba;
#endif
    cdbp->c6_len    = block_count;
    sr.sr_dma_dir    = SR_DMA_WR;
    sr.sr_addr    = (char *)bp;
    sr.sr_dma_max    = block_count * BLOCK_SIZE;
    sr.sr_ioto    = 10;
    return(do_ioc(&sr));

} /* gs_write() */

cdb_clr(cdbp)
union cdb *cdbp;
{
    int i;
    char *p;

    p = (char *)cdbp;
    for(i=0; i<sizeof(union cdb); i++)
        *p++ = 0;
}

do_ioc(sr)
struct scsi_req *sr;
{

    if (ioctl(fd,SGIOCREQ,sr) < 0) {
        printf("..Error executing ioctl\n");
        printf("errno = %d\n",errno);
        perror("ioctl(SGIOCREQ)");
        return(1);
    }
    if(sr->sr_io_status) {
        printf("sr_io_status = 0x%X\n",sr->sr_io_status);
        if(sr->sr_io_status == SR_IOST_CHKSV) {
            printf("   sense key = %02XH   sense code = %02XH\n",
                sr->sr_esense.er_sensekey,
                sr->sr_esense.er_addsensecode);
        }
        printf("SCSI status = %02XH\n",sr->sr_scsi_status);
        return(1);
    }
    return(0);
} /* do_ioc() */