+/**
+ * atapi_packet_task - Write CDB bytes to hardware
+ * @_data: Port to which ATAPI device is attached.
+ *
+ * When device has indicated its readiness to accept
+ * a CDB, this function is called. Send the CDB.
+ * If DMA is to be performed, exit immediately.
+ * Otherwise, we are in polling mode, so poll
+ * status under operation succeeds or fails.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep)
+ */
+
+static void atapi_packet_task(void *_data)
+{
+ struct ata_port *ap = _data;
+ struct ata_queued_cmd *qc;
+ u8 status;
+
+ qc = ata_qc_from_tag(ap, ap->active_tag);
+ WARN_ON(qc == NULL);
+ WARN_ON(!(qc->flags & ATA_QCFLAG_ACTIVE));
+
+ /* sleep-wait for BSY to clear */
+ DPRINTK("busy wait\n");
+ if (ata_busy_sleep(ap, ATA_TMOUT_CDB_QUICK, ATA_TMOUT_CDB)) {
+ qc->err_mask |= AC_ERR_TIMEOUT;
+ goto err_out;
+ }
+
+ /* make sure DRQ is set */
+ status = ata_chk_status(ap);
+ if ((status & (ATA_BUSY | ATA_DRQ)) != ATA_DRQ) {
+ qc->err_mask |= AC_ERR_HSM;
+ goto err_out;
+ }
+
+ /* send SCSI cdb */
+ DPRINTK("send cdb\n");
+ WARN_ON(qc->dev->cdb_len < 12);
+
+ if (qc->tf.protocol == ATA_PROT_ATAPI_DMA ||
+ qc->tf.protocol == ATA_PROT_ATAPI_NODATA) {
+ unsigned long flags;
+
+ /* Once we're done issuing command and kicking bmdma,
+ * irq handler takes over. To not lose irq, we need
+ * to clear NOINTR flag before sending cdb, but
+ * interrupt handler shouldn't be invoked before we're
+ * finished. Hence, the following locking.
+ */
+ spin_lock_irqsave(&ap->host_set->lock, flags);
+ ap->flags &= ~ATA_FLAG_NOINTR;
+ ata_data_xfer(ap, qc->cdb, qc->dev->cdb_len, 1);
+ if (qc->tf.protocol == ATA_PROT_ATAPI_DMA)
+ ap->ops->bmdma_start(qc); /* initiate bmdma */
+ spin_unlock_irqrestore(&ap->host_set->lock, flags);
+ } else {
+ ata_data_xfer(ap, qc->cdb, qc->dev->cdb_len, 1);
+
+ /* PIO commands are handled by polling */
+ ap->hsm_task_state = HSM_ST;
+ ata_port_queue_task(ap, ata_pio_task, ap, 0);
+ }
+
+ return;
+
+err_out:
+ ata_poll_qc_complete(qc);
+}
+