+/**
+ * ata_hsm_move - move the HSM to the next state.
+ * @ap: the target ata_port
+ * @qc: qc on going
+ * @status: current device status
+ * @in_wq: 1 if called from workqueue, 0 otherwise
+ *
+ * RETURNS:
+ * 1 when poll next status needed, 0 otherwise.
+ */
+
+static int ata_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc,
+ u8 status, int in_wq)
+{
+ unsigned long flags = 0;
+ int poll_next;
+
+ WARN_ON((qc->flags & ATA_QCFLAG_ACTIVE) == 0);
+
+ /* Make sure ata_qc_issue_prot() does not throw things
+ * like DMA polling into the workqueue. Notice that
+ * in_wq is not equivalent to (qc->tf.flags & ATA_TFLAG_POLLING).
+ */
+ WARN_ON(in_wq != ((qc->tf.flags & ATA_TFLAG_POLLING) ||
+ (ap->hsm_task_state == HSM_ST_FIRST &&
+ ((qc->tf.protocol == ATA_PROT_PIO &&
+ (qc->tf.flags & ATA_TFLAG_WRITE)) ||
+ (is_atapi_taskfile(&qc->tf) &&
+ !(qc->dev->flags & ATA_DFLAG_CDB_INTR))))));
+
+ /* check error */
+ if (unlikely(status & (ATA_ERR | ATA_DF))) {
+ qc->err_mask |= AC_ERR_DEV;
+ ap->hsm_task_state = HSM_ST_ERR;
+ }
+
+fsm_start:
+ switch (ap->hsm_task_state) {
+ case HSM_ST_FIRST:
+ /* Send first data block or PACKET CDB */
+
+ /* If polling, we will stay in the work queue after
+ * sending the data. Otherwise, interrupt handler
+ * takes over after sending the data.
+ */
+ poll_next = (qc->tf.flags & ATA_TFLAG_POLLING);
+
+ /* check device status */
+ if (unlikely((status & (ATA_BUSY | ATA_DRQ)) != ATA_DRQ)) {
+ /* Wrong status. Let EH handle this */
+ qc->err_mask |= AC_ERR_HSM;
+ ap->hsm_task_state = HSM_ST_ERR;
+ goto fsm_start;
+ }
+
+ /* Send the CDB (atapi) or the first data block (ata pio out).
+ * During the state transition, interrupt handler shouldn't
+ * be invoked before the data transfer is complete and
+ * hsm_task_state is changed. Hence, the following locking.
+ */
+ if (in_wq)
+ spin_lock_irqsave(&ap->host_set->lock, flags);
+
+ if (qc->tf.protocol == ATA_PROT_PIO) {
+ /* PIO data out protocol.
+ * send first data block.
+ */
+
+ /* ata_pio_sectors() might change the state
+ * to HSM_ST_LAST. so, the state is changed here
+ * before ata_pio_sectors().
+ */
+ ap->hsm_task_state = HSM_ST;
+ ata_pio_sectors(qc);
+ ata_altstatus(ap); /* flush */
+ } else
+ /* send CDB */
+ atapi_send_cdb(ap, qc);
+
+ if (in_wq)
+ spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+ /* if polling, ata_pio_task() handles the rest.
+ * otherwise, interrupt handler takes over from here.
+ */
+ break;
+
+ case HSM_ST:
+ /* complete command or read/write the data register */
+ if (qc->tf.protocol == ATA_PROT_ATAPI) {
+ /* ATAPI PIO protocol */
+ if ((status & ATA_DRQ) == 0) {
+ /* no more data to transfer */
+ ap->hsm_task_state = HSM_ST_LAST;
+ goto fsm_start;
+ }
+
+ atapi_pio_bytes(qc);
+
+ if (unlikely(ap->hsm_task_state == HSM_ST_ERR))
+ /* bad ireason reported by device */
+ goto fsm_start;
+
+ } else {
+ /* ATA PIO protocol */
+ if (unlikely((status & ATA_DRQ) == 0)) {
+ /* handle BSY=0, DRQ=0 as error */
+ qc->err_mask |= AC_ERR_HSM;
+ ap->hsm_task_state = HSM_ST_ERR;
+ goto fsm_start;
+ }
+
+ ata_pio_sectors(qc);
+
+ if (ap->hsm_task_state == HSM_ST_LAST &&
+ (!(qc->tf.flags & ATA_TFLAG_WRITE))) {
+ /* all data read */
+ ata_altstatus(ap);
+ status = ata_chk_status(ap);
+ goto fsm_start;
+ }
+ }
+
+ ata_altstatus(ap); /* flush */
+ poll_next = 1;
+ break;
+
+ case HSM_ST_LAST:
+ if (unlikely(!ata_ok(status))) {
+ qc->err_mask |= __ac_err_mask(status);
+ ap->hsm_task_state = HSM_ST_ERR;
+ goto fsm_start;
+ }
+
+ /* no more data to transfer */
+ DPRINTK("ata%u: command complete, drv_stat 0x%x\n",
+ ap->id, status);
+
+ WARN_ON(qc->err_mask);
+
+ ap->hsm_task_state = HSM_ST_IDLE;
+
+ /* complete taskfile transaction */
+ if (in_wq)
+ ata_poll_qc_complete(qc);
+ else
+ ata_qc_complete(qc);
+
+ poll_next = 0;
+ break;
+
+ case HSM_ST_ERR:
+ if (qc->tf.command != ATA_CMD_PACKET)
+ printk(KERN_ERR "ata%u: command error, drv_stat 0x%x\n",
+ ap->id, status);
+
+ /* make sure qc->err_mask is available to
+ * know what's wrong and recover
+ */
+ WARN_ON(qc->err_mask == 0);
+
+ ap->hsm_task_state = HSM_ST_IDLE;
+
+ if (in_wq)
+ ata_poll_qc_complete(qc);
+ else
+ ata_qc_complete(qc);
+
+ poll_next = 0;
+ break;
+ default:
+ poll_next = 0;
+ BUG();
+ }
+
+ return poll_next;
+}
+