tran_getcap() Entry Point

The tran_getcap(9E) entry point for a SCSI HBA driver is called when a target driver calls scsi_ifgetcap(9F) to determine the current value of one of a set of SCSA-defined capabilities.

The target driver can request the current setting of the capability for a particular target by setting the whom parameter to nonzero. A whom value of 0 means the request is for the current setting of the capability for the SCSI bus or for adapter hardware in general.

tran_getcap() should return -1 for undefined capabilities or the current value of the requested capability.

The HBA driver can use the function scsi_hba_lookup_capstr(9F) to compare the capability string against the canonical set of defined capabilities.

Example 15–10 HBA Driver tran_getcap(9E) Entry Point

static int
isp_scsi_getcap(
    struct scsi_address    *ap,
    char                   *cap,
    int                    whom)
{
    struct isp             *isp;
    int                    rval = 0;
    u_char                 tgt = ap->a_target;

    /*
     * We don't allow getting capabilities for other targets
     */
    if (cap == NULL || whom  == 0)    {
        return (-1);
    }

    isp = (struct isp *)ap->a_hba_tran->tran_hba_private;

    ISP_MUTEX_ENTER(isp);

    switch (scsi_hba_lookup_capstr(cap)) {

    case SCSI_CAP_DMA_MAX:
        rval = 1 << 24; /* Limit to 16MB max transfer */
        break;
    case SCSI_CAP_MSG_OUT:
        rval = 1;
        break;
    case SCSI_CAP_DISCONNECT:
        if ((isp->isp_target_scsi_options[tgt] &
            SCSI_OPTIONS_DR) == 0) {
            break;
        } else if (
            (isp->isp_cap[tgt] & ISP_CAP_DISCONNECT) == 0) {
            break;
        }
        rval = 1;
        break;
    case SCSI_CAP_SYNCHRONOUS:
        if ((isp->isp_target_scsi_options[tgt] &
            SCSI_OPTIONS_SYNC) == 0) {
            break;
        } else if (
            (isp->isp_cap[tgt] & ISP_CAP_SYNC) == 0) {
            break;
        }
        rval = 1;
        break;
    case SCSI_CAP_WIDE_XFER:
        if ((isp->isp_target_scsi_options[tgt] &
            SCSI_OPTIONS_WIDE) == 0) {
            break;
        } else if (
            (isp->isp_cap[tgt] & ISP_CAP_WIDE) == 0) {
            break;
        }
        rval = 1;
        break;
    case SCSI_CAP_TAGGED_QING:
        if ((isp->isp_target_scsi_options[tgt] &
            SCSI_OPTIONS_DR) == 0 ||
            (isp->isp_target_scsi_options[tgt] &
            SCSI_OPTIONS_TAG) == 0) {
            break;
        } else if (
            (isp->isp_cap[tgt] & ISP_CAP_TAG) == 0) {
            break;
        }
        rval = 1;
        break;
    case SCSI_CAP_UNTAGGED_QING:
        rval = 1;
        break;
    case SCSI_CAP_PARITY:
        if (isp->isp_target_scsi_options[tgt] &
            SCSI_OPTIONS_PARITY) {
            rval = 1;
        }
        break;
    case SCSI_CAP_INITIATOR_ID:
        rval = isp->isp_initiator_id;
        break;
    case SCSI_CAP_ARQ:
        if (isp->isp_cap[tgt] & ISP_CAP_AUTOSENSE) {
            rval = 1;
        }
        break;
    case SCSI_CAP_LINKED_CMDS:
        break;
    case SCSI_CAP_RESET_NOTIFICATION:
        rval = 1;
        break;
    case SCSI_CAP_GEOMETRY:
        rval = (64 << 16) | 32;
        break;

    default:
        rval = -1;
        break;
    }

    ISP_MUTEX_EXIT(isp);

    return (rval);
}