Merge branch 'irq-pio'

Conflicts:

	drivers/scsi/libata-core.c
	include/linux/libata.h

1 files changed, 495 insertions, 308 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 2969599ec0b..c859b96b891 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1345,11 +1345,19 @@ static int ata_dev_configure(struct ata_device *dev, int print_info)
                                         dev->cylinders, dev->heads, dev->sectors);
                 }
 
+                if (dev->id[59] & 0x100) {
+                        dev->multi_count = dev->id[59] & 0xff;
+                        DPRINTK("ata%u: dev %u multi count %u\n",
+                                ap->id, dev->devno, dev->multi_count);
+                }
+
                 dev->cdb_len = 16;
         }
 
         /* ATAPI-specific feature tests */
         else if (dev->class == ATA_DEV_ATAPI) {
+                char *cdb_intr_string = "";
+
                 rc = atapi_cdb_len(id);
                 if ((rc < 12) || (rc > ATAPI_CDB_LEN)) {
                         ata_dev_printk(dev, KERN_WARNING,
@@ -1359,10 +1367,16 @@ static int ata_dev_configure(struct ata_device *dev, int print_info)
                 }
                 dev->cdb_len = (unsigned int) rc;
 
+                if (ata_id_cdb_intr(dev->id)) {
+                        dev->flags |= ATA_DFLAG_CDB_INTR;
+                        cdb_intr_string = ", CDB intr";
+                }
+
                 /* print device info to dmesg */
                 if (print_info)
-                        ata_dev_printk(dev, KERN_INFO, "ATAPI, max %s\n",
-                                       ata_mode_string(xfer_mask));
+                        ata_dev_printk(dev, KERN_INFO, "ATAPI, max %s%s\n",
+                                       ata_mode_string(xfer_mask),
+                                       cdb_intr_string);
         }
 
         ap->host->max_cmd_len = 0;
@@ -3211,6 +3225,15 @@ int ata_check_atapi_dma(struct ata_queued_cmd *qc)
         if (ap->ops->check_atapi_dma)
                 rc = ap->ops->check_atapi_dma(qc);
 
+        /* We don't support polling DMA.
+         * Use PIO if the LLDD handles only interrupts in
+         * the HSM_ST_LAST state and the ATAPI device
+         * generates CDB interrupts.
+         */
+        if ((ap->flags & ATA_FLAG_PIO_POLLING) &&
+            (qc->dev->flags & ATA_DFLAG_CDB_INTR))
+                rc = 1;
+
         return rc;
 }
 /**
@@ -3458,7 +3481,6 @@ void ata_poll_qc_complete(struct ata_queued_cmd *qc)
                 qc = ata_qc_from_tag(ap, qc->tag);
                 if (qc) {
                         if (!(qc->err_mask & AC_ERR_HSM)) {
-                                ap->flags &= ~ATA_FLAG_NOINTR;
                                 ata_irq_on(ap);
                                 ata_qc_complete(qc);
                         } else
@@ -3466,7 +3488,6 @@ void ata_poll_qc_complete(struct ata_queued_cmd *qc)
                 }
         } else {
                 /* old EH */
-                ap->flags &= ~ATA_FLAG_NOINTR;
                 ata_irq_on(ap);
                 ata_qc_complete(qc);
         }
@@ -3475,105 +3496,6 @@ void ata_poll_qc_complete(struct ata_queued_cmd *qc)
 }
 
 /**
- *      ata_pio_poll - poll using PIO, depending on current state
- *      @qc: qc in progress
- *
- *      LOCKING:
- *      None.  (executing in kernel thread context)
- *
- *      RETURNS:
- *      timeout value to use
- */
-static unsigned long ata_pio_poll(struct ata_queued_cmd *qc)
-{
-        struct ata_port *ap = qc->ap;
-        u8 status;
-        unsigned int poll_state = HSM_ST_UNKNOWN;
-        unsigned int reg_state = HSM_ST_UNKNOWN;
-
-        switch (ap->hsm_task_state) {
-        case HSM_ST:
-        case HSM_ST_POLL:
-                poll_state = HSM_ST_POLL;
-                reg_state = HSM_ST;
-                break;
-        case HSM_ST_LAST:
-        case HSM_ST_LAST_POLL:
-                poll_state = HSM_ST_LAST_POLL;
-                reg_state = HSM_ST_LAST;
-                break;
-        default:
-                BUG();
-                break;
-        }
-
-        status = ata_chk_status(ap);
-        if (status & ATA_BUSY) {
-                if (time_after(jiffies, ap->pio_task_timeout)) {
-                        qc->err_mask |= AC_ERR_TIMEOUT;
-                        ap->hsm_task_state = HSM_ST_TMOUT;
-                        return 0;
-                }
-                ap->hsm_task_state = poll_state;
-                return ATA_SHORT_PAUSE;
-        }
-
-        ap->hsm_task_state = reg_state;
-        return 0;
-}
-
-/**
- *      ata_pio_complete - check if drive is busy or idle
- *      @qc: qc to complete
- *
- *      LOCKING:
- *      None.  (executing in kernel thread context)
- *
- *      RETURNS:
- *      Non-zero if qc completed, zero otherwise.
- */
-static int ata_pio_complete(struct ata_queued_cmd *qc)
-{
-        struct ata_port *ap = qc->ap;
-        u8 drv_stat;
-
-        /*
-         * This is purely heuristic.  This is a fast path.  Sometimes when
-         * we enter, BSY will be cleared in a chk-status or two.  If not,
-         * the drive is probably seeking or something.  Snooze for a couple
-         * msecs, then chk-status again.  If still busy, fall back to
-         * HSM_ST_POLL state.
-         */
-        drv_stat = ata_busy_wait(ap, ATA_BUSY, 10);
-        if (drv_stat & ATA_BUSY) {
-                msleep(2);
-                drv_stat = ata_busy_wait(ap, ATA_BUSY, 10);
-                if (drv_stat & ATA_BUSY) {
-                        ap->hsm_task_state = HSM_ST_LAST_POLL;
-                        ap->pio_task_timeout = jiffies + ATA_TMOUT_PIO;
-                        return 0;
-                }
-        }
-
-        drv_stat = ata_wait_idle(ap);
-        if (!ata_ok(drv_stat)) {
-                qc->err_mask |= __ac_err_mask(drv_stat);
-                ap->hsm_task_state = HSM_ST_ERR;
-                return 0;
-        }
-
-        ap->hsm_task_state = HSM_ST_IDLE;
-
-        WARN_ON(qc->err_mask);
-        ata_poll_qc_complete(qc);
-
-        /* another command may start at this point */
-
-        return 1;
-}
-
-
-/**
  *      swap_buf_le16 - swap halves of 16-bit words in place
  *      @buf:  Buffer to swap
  *      @buf_words:  Number of 16-bit words in buffer.
@@ -3741,7 +3663,23 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
         page = nth_page(page, (offset >> PAGE_SHIFT));
         offset %= PAGE_SIZE;
 
-        buf = kmap(page) + offset;
+        DPRINTK("data %s\n", qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
+
+        if (PageHighMem(page)) {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                buf = kmap_atomic(page, KM_IRQ0);
+
+                /* do the actual data transfer */
+                ata_data_xfer(ap, buf + offset, ATA_SECT_SIZE, do_write);
+
+                kunmap_atomic(buf, KM_IRQ0);
+                local_irq_restore(flags);
+        } else {
+                buf = page_address(page);
+                ata_data_xfer(ap, buf + offset, ATA_SECT_SIZE, do_write);
+        }
 
         qc->cursect++;
         qc->cursg_ofs++;
@@ -3750,14 +3688,68 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
                 qc->cursg++;
                 qc->cursg_ofs = 0;
         }
+}
 
-        DPRINTK("data %s\n", qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
+/**
+ *      ata_pio_sectors - Transfer one or many 512-byte sectors.
+ *      @qc: Command on going
+ *
+ *      Transfer one or many ATA_SECT_SIZE of data from/to the 
+ *      ATA device for the DRQ request.
+ *
+ *      LOCKING:
+ *      Inherited from caller.
+ */
+
+static void ata_pio_sectors(struct ata_queued_cmd *qc)
+{
+        if (is_multi_taskfile(&qc->tf)) {
+                /* READ/WRITE MULTIPLE */
+                unsigned int nsect;
+
+                WARN_ON(qc->dev->multi_count == 0);
+
+                nsect = min(qc->nsect - qc->cursect, qc->dev->multi_count);
+                while (nsect--)
+                        ata_pio_sector(qc);
+        } else
+                ata_pio_sector(qc);
+}
+
+/**
+ *      atapi_send_cdb - Write CDB bytes to hardware
+ *      @ap: Port to which ATAPI device is attached.
+ *      @qc: Taskfile currently active
+ *
+ *      When device has indicated its readiness to accept
+ *      a CDB, this function is called.  Send the CDB.
+ *
+ *      LOCKING:
+ *      caller.
+ */
+
+static void atapi_send_cdb(struct ata_port *ap, struct ata_queued_cmd *qc)
+{
+        /* send SCSI cdb */
+        DPRINTK("send cdb\n");
+        WARN_ON(qc->dev->cdb_len < 12);
 
-        /* do the actual data transfer */
-        do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
-        ata_data_xfer(ap, buf, ATA_SECT_SIZE, do_write);
+        ata_data_xfer(ap, qc->cdb, qc->dev->cdb_len, 1);
+        ata_altstatus(ap); /* flush */
 
-        kunmap(page);
+        switch (qc->tf.protocol) {
+        case ATA_PROT_ATAPI:
+                ap->hsm_task_state = HSM_ST;
+                break;
+        case ATA_PROT_ATAPI_NODATA:
+                ap->hsm_task_state = HSM_ST_LAST;
+                break;
+        case ATA_PROT_ATAPI_DMA:
+                ap->hsm_task_state = HSM_ST_LAST;
+                /* initiate bmdma */
+                ap->ops->bmdma_start(qc);
+                break;
+        }
 }
 
 /**
@@ -3823,7 +3815,23 @@ next_sg:
         /* don't cross page boundaries */
         count = min(count, (unsigned int)PAGE_SIZE - offset);
 
-        buf = kmap(page) + offset;
+        DPRINTK("data %s\n", qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
+
+        if (PageHighMem(page)) {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                buf = kmap_atomic(page, KM_IRQ0);
+
+                /* do the actual data transfer */
+                ata_data_xfer(ap, buf + offset, count, do_write);
+
+                kunmap_atomic(buf, KM_IRQ0);
+                local_irq_restore(flags);
+        } else {
+                buf = page_address(page);
+                ata_data_xfer(ap, buf + offset, count, do_write);
+        }
 
         bytes -= count;
         qc->curbytes += count;
@@ -3834,13 +3842,6 @@ next_sg:
                 qc->cursg_ofs = 0;
         }
 
-        DPRINTK("data %s\n", qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
-
-        /* do the actual data transfer */
-        ata_data_xfer(ap, buf, count, do_write);
-
-        kunmap(page);
-
         if (bytes)
                 goto next_sg;
 }
@@ -3877,6 +3878,8 @@ static void atapi_pio_bytes(struct ata_queued_cmd *qc)
         if (do_write != i_write)
                 goto err_out;
 
+        VPRINTK("ata%u: xfering %d bytes\n", ap->id, bytes);
+
         __atapi_pio_bytes(qc, bytes);
 
         return;
@@ -3888,186 +3891,294 @@ err_out:
 }
 
 /**
- *      ata_pio_block - start PIO on a block
- *      @qc: qc to transfer block for
+ *      ata_hsm_ok_in_wq - Check if the qc can be handled in the workqueue.
+ *      @ap: the target ata_port
+ *      @qc: qc on going
  *
- *      LOCKING:
- *      None.  (executing in kernel thread context)
+ *      RETURNS:
+ *      1 if ok in workqueue, 0 otherwise.
  */
-static void ata_pio_block(struct ata_queued_cmd *qc)
+
+static inline int ata_hsm_ok_in_wq(struct ata_port *ap, struct ata_queued_cmd *qc)
 {
-        struct ata_port *ap = qc->ap;
-        u8 status;
+        if (qc->tf.flags & ATA_TFLAG_POLLING)
+                return 1;
 
-        /*
-         * This is purely heuristic.  This is a fast path.
-         * Sometimes when we enter, BSY will be cleared in
-         * a chk-status or two.  If not, the drive is probably seeking
-         * or something.  Snooze for a couple msecs, then
-         * chk-status again.  If still busy, fall back to
-         * HSM_ST_POLL state.
-         */
-        status = ata_busy_wait(ap, ATA_BUSY, 5);
-        if (status & ATA_BUSY) {
-                msleep(2);
-                status = ata_busy_wait(ap, ATA_BUSY, 10);
-                if (status & ATA_BUSY) {
-                        ap->hsm_task_state = HSM_ST_POLL;
-                        ap->pio_task_timeout = jiffies + ATA_TMOUT_PIO;
-                        return;
-                }
-        }
+        if (ap->hsm_task_state == HSM_ST_FIRST) {
+                if (qc->tf.protocol == ATA_PROT_PIO &&
+                    (qc->tf.flags & ATA_TFLAG_WRITE))
+                    return 1;
 
-        /* check error */
-        if (status & (ATA_ERR | ATA_DF)) {
-                qc->err_mask |= AC_ERR_DEV;
-                ap->hsm_task_state = HSM_ST_ERR;
-                return;
+                if (is_atapi_taskfile(&qc->tf) &&
+                    !(qc->dev->flags & ATA_DFLAG_CDB_INTR))
+                        return 1;
         }
 
-        /* transfer data if any */
-        if (is_atapi_taskfile(&qc->tf)) {
-                /* DRQ=0 means no more data to transfer */
-                if ((status & ATA_DRQ) == 0) {
-                        ap->hsm_task_state = HSM_ST_LAST;
-                        return;
-                }
+        return 0;
+}
 
-                atapi_pio_bytes(qc);
-        } else {
-                /* handle BSY=0, DRQ=0 as error */
-                if ((status & ATA_DRQ) == 0) {
+/**
+ *      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 != ata_hsm_ok_in_wq(ap, qc));
+
+fsm_start:
+        DPRINTK("ata%u: protocol %d task_state %d (dev_stat 0x%X)\n",
+                ap->id, qc->tf.protocol, ap->hsm_task_state, status);
+
+        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;
-                        return;
+                        goto fsm_start;
                 }
 
-                ata_pio_sector(qc);
-        }
-}
+                /* Device should not ask for data transfer (DRQ=1)
+                 * when it finds something wrong.
+                 * We ignore DRQ here and stop the HSM by
+                 * changing hsm_task_state to HSM_ST_ERR and
+                 * let the EH abort the command or reset the device.
+                 */
+                if (unlikely(status & (ATA_ERR | ATA_DF))) {
+                        printk(KERN_WARNING "ata%d: DRQ=1 with device error, dev_stat 0x%X\n",
+                               ap->id, status);
+                        qc->err_mask |= AC_ERR_DEV;
+                        ap->hsm_task_state = HSM_ST_ERR;
+                        goto fsm_start;
+                }
 
-static void ata_pio_error(struct ata_queued_cmd *qc)
-{
-        struct ata_port *ap = qc->ap;
+                /* 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.command != ATA_CMD_PACKET)
-                ata_dev_printk(qc->dev, KERN_WARNING, "PIO error\n");
+                if (qc->tf.protocol == ATA_PROT_PIO) {
+                        /* PIO data out protocol.
+                         * send first data block.
+                         */
 
-        /* make sure qc->err_mask is available to
-         * know what's wrong and recover
-         */
-        WARN_ON(qc->err_mask == 0);
+                        /* 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;
 
-        ap->hsm_task_state = HSM_ST_IDLE;
+        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;
+                        }
 
-        ata_poll_qc_complete(qc);
-}
+                        /* Device should not ask for data transfer (DRQ=1)
+                         * when it finds something wrong.
+                         * We ignore DRQ here and stop the HSM by
+                         * changing hsm_task_state to HSM_ST_ERR and
+                         * let the EH abort the command or reset the device.
+                         */
+                        if (unlikely(status & (ATA_ERR | ATA_DF))) {
+                                printk(KERN_WARNING "ata%d: DRQ=1 with device error, dev_stat 0x%X\n",
+                                       ap->id, status);
+                                qc->err_mask |= AC_ERR_DEV;
+                                ap->hsm_task_state = HSM_ST_ERR;
+                                goto fsm_start;
+                        }
 
-static void ata_pio_task(void *_data)
-{
-        struct ata_queued_cmd *qc = _data;
-        struct ata_port *ap = qc->ap;
-        unsigned long timeout;
-        int qc_completed;
+                        atapi_pio_bytes(qc);
 
-fsm_start:
-        timeout = 0;
-        qc_completed = 0;
+                        if (unlikely(ap->hsm_task_state == HSM_ST_ERR))
+                                /* bad ireason reported by device */
+                                goto fsm_start;
 
-        switch (ap->hsm_task_state) {
-        case HSM_ST_IDLE:
-                return;
+                } 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;
+                        }
 
-        case HSM_ST:
-                ata_pio_block(qc);
+                        /* For PIO reads, some devices may ask for
+                         * data transfer (DRQ=1) alone with ERR=1.
+                         * We respect DRQ here and transfer one
+                         * block of junk data before changing the
+                         * hsm_task_state to HSM_ST_ERR.
+                         *
+                         * For PIO writes, ERR=1 DRQ=1 doesn't make
+                         * sense since the data block has been
+                         * transferred to the device.
+                         */
+                        if (unlikely(status & (ATA_ERR | ATA_DF))) {
+                                /* data might be corrputed */
+                                qc->err_mask |= AC_ERR_DEV;
+
+                                if (!(qc->tf.flags & ATA_TFLAG_WRITE)) {
+                                        ata_pio_sectors(qc);
+                                        ata_altstatus(ap);
+                                        status = ata_wait_idle(ap);
+                                }
+
+                                /* ata_pio_sectors() might change the
+                                 * state to HSM_ST_LAST. so, the state
+                                 * is changed after ata_pio_sectors().
+                                 */
+                                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_wait_idle(ap);
+                                goto fsm_start;
+                        }
+                }
+
+                ata_altstatus(ap); /* flush */
+                poll_next = 1;
                 break;
 
         case HSM_ST_LAST:
-                qc_completed = ata_pio_complete(qc);
-                break;
+                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: dev %u command complete, drv_stat 0x%x\n",
+                        ap->id, qc->dev->devno, status);
+
+                WARN_ON(qc->err_mask);
 
-        case HSM_ST_POLL:
-        case HSM_ST_LAST_POLL:
-                timeout = ata_pio_poll(qc);
+                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_TMOUT:
         case HSM_ST_ERR:
-                ata_pio_error(qc);
-                return;
+                if (qc->tf.command != ATA_CMD_PACKET)
+                        printk(KERN_ERR "ata%u: dev %u command error, drv_stat 0x%x\n",
+                               ap->id, qc->dev->devno, 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;
+
+                /* complete taskfile transaction */
+                if (in_wq)
+                        ata_poll_qc_complete(qc);
+                else
+                        ata_qc_complete(qc);
+
+                poll_next = 0;
+                break;
+        default:
+                poll_next = 0;
+                BUG();
         }
 
-        if (timeout)
-                ata_port_queue_task(ap, ata_pio_task, qc, timeout);
-        else if (!qc_completed)
-                goto fsm_start;
+        return poll_next;
 }
 
-/**
- *      atapi_packet_task - Write CDB bytes to hardware
- *      @_data: qc in progress
- *
- *      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)
+static void ata_pio_task(void *_data)
 {
         struct ata_queued_cmd *qc = _data;
         struct ata_port *ap = qc->ap;
         u8 status;
+        int poll_next;
 
-        /* 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);
+fsm_start:
+        WARN_ON(ap->hsm_task_state == HSM_ST_IDLE);
 
-                /* PIO commands are handled by polling */
-                ap->hsm_task_state = HSM_ST;
-                ata_port_queue_task(ap, ata_pio_task, qc, 0);
+        /*
+         * This is purely heuristic.  This is a fast path.
+         * Sometimes when we enter, BSY will be cleared in
+         * a chk-status or two.  If not, the drive is probably seeking
+         * or something.  Snooze for a couple msecs, then
+         * chk-status again.  If still busy, queue delayed work.
+         */
+        status = ata_busy_wait(ap, ATA_BUSY, 5);
+        if (status & ATA_BUSY) {
+                msleep(2);
+                status = ata_busy_wait(ap, ATA_BUSY, 10);
+                if (status & ATA_BUSY) {
+                        ata_port_queue_task(ap, ata_pio_task, qc, ATA_SHORT_PAUSE);
+                        return;
+                }
         }
 
-        return;
+        /* move the HSM */
+        poll_next = ata_hsm_move(ap, qc, status, 1);
 
-err_out:
-        ata_poll_qc_complete(qc);
+        /* another command or interrupt handler
+         * may be running at this point.
+         */
+        if (poll_next)
+                goto fsm_start;
 }
 
 /**
@@ -4322,43 +4433,105 @@ unsigned int ata_qc_issue_prot(struct ata_queued_cmd *qc)
 {
         struct ata_port *ap = qc->ap;
 
+        /* Use polling pio if the LLD doesn't handle
+         * interrupt driven pio and atapi CDB interrupt.
+         */
+        if (ap->flags & ATA_FLAG_PIO_POLLING) {
+                switch (qc->tf.protocol) {
+                case ATA_PROT_PIO:
+                case ATA_PROT_ATAPI:
+                case ATA_PROT_ATAPI_NODATA:
+                        qc->tf.flags |= ATA_TFLAG_POLLING;
+                        break;
+                case ATA_PROT_ATAPI_DMA:
+                        if (qc->dev->flags & ATA_DFLAG_CDB_INTR)
+                                /* see ata_check_atapi_dma() */
+                                BUG();
+                        break;
+                default:
+                        break;
+                }
+        }
+
+        /* select the device */
         ata_dev_select(ap, qc->dev->devno, 1, 0);
 
+        /* start the command */
         switch (qc->tf.protocol) {
         case ATA_PROT_NODATA:
+                if (qc->tf.flags & ATA_TFLAG_POLLING)
+                        ata_qc_set_polling(qc);
+
                 ata_tf_to_host(ap, &qc->tf);
+                ap->hsm_task_state = HSM_ST_LAST;
+
+                if (qc->tf.flags & ATA_TFLAG_POLLING)
+                        ata_port_queue_task(ap, ata_pio_task, qc, 0);
+
                 break;
 
         case ATA_PROT_DMA:
+                WARN_ON(qc->tf.flags & ATA_TFLAG_POLLING);
+
                 ap->ops->tf_load(ap, &qc->tf);   /* load tf registers */
                 ap->ops->bmdma_setup(qc);           /* set up bmdma */
                 ap->ops->bmdma_start(qc);           /* initiate bmdma */
+                ap->hsm_task_state = HSM_ST_LAST;
                 break;
 
-        case ATA_PROT_PIO: /* load tf registers, initiate polling pio */
-                ata_qc_set_polling(qc);
-                ata_tf_to_host(ap, &qc->tf);
-                ap->hsm_task_state = HSM_ST;
-                ata_port_queue_task(ap, ata_pio_task, qc, 0);
-                break;
+        case ATA_PROT_PIO:
+                if (qc->tf.flags & ATA_TFLAG_POLLING)
+                        ata_qc_set_polling(qc);
 
-        case ATA_PROT_ATAPI:
-                ata_qc_set_polling(qc);
                 ata_tf_to_host(ap, &qc->tf);
-                ata_port_queue_task(ap, atapi_packet_task, qc, 0);
+
+                if (qc->tf.flags & ATA_TFLAG_WRITE) {
+                        /* PIO data out protocol */
+                        ap->hsm_task_state = HSM_ST_FIRST;
+                        ata_port_queue_task(ap, ata_pio_task, qc, 0);
+
+                        /* always send first data block using
+                         * the ata_pio_task() codepath.
+                         */
+                } else {
+                        /* PIO data in protocol */
+                        ap->hsm_task_state = HSM_ST;
+
+                        if (qc->tf.flags & ATA_TFLAG_POLLING)
+                                ata_port_queue_task(ap, ata_pio_task, qc, 0);
+
+                        /* if polling, ata_pio_task() handles the rest.
+                         * otherwise, interrupt handler takes over from here.
+                         */
+                }
+
                 break;
 
+        case ATA_PROT_ATAPI:
         case ATA_PROT_ATAPI_NODATA:
-                ap->flags |= ATA_FLAG_NOINTR;
+                if (qc->tf.flags & ATA_TFLAG_POLLING)
+                        ata_qc_set_polling(qc);
+
                 ata_tf_to_host(ap, &qc->tf);
-                ata_port_queue_task(ap, atapi_packet_task, qc, 0);
+
+                ap->hsm_task_state = HSM_ST_FIRST;
+
+                /* send cdb by polling if no cdb interrupt */
+                if ((!(qc->dev->flags & ATA_DFLAG_CDB_INTR)) ||
+                    (qc->tf.flags & ATA_TFLAG_POLLING))
+                        ata_port_queue_task(ap, ata_pio_task, qc, 0);
                 break;
 
         case ATA_PROT_ATAPI_DMA:
-                ap->flags |= ATA_FLAG_NOINTR;
+                WARN_ON(qc->tf.flags & ATA_TFLAG_POLLING);
+
                 ap->ops->tf_load(ap, &qc->tf);   /* load tf registers */
                 ap->ops->bmdma_setup(qc);           /* set up bmdma */
-                ata_port_queue_task(ap, atapi_packet_task, qc, 0);
+                ap->hsm_task_state = HSM_ST_FIRST;
+
+                /* send cdb by polling if no cdb interrupt */
+                if (!(qc->dev->flags & ATA_DFLAG_CDB_INTR))
+                        ata_port_queue_task(ap, ata_pio_task, qc, 0);
                 break;
 
         default:
@@ -4388,52 +4561,66 @@ unsigned int ata_qc_issue_prot(struct ata_queued_cmd *qc)
 inline unsigned int ata_host_intr (struct ata_port *ap,
                                    struct ata_queued_cmd *qc)
 {
-        u8 status, host_stat;
-
-        switch (qc->tf.protocol) {
-
-        case ATA_PROT_DMA:
-        case ATA_PROT_ATAPI_DMA:
-        case ATA_PROT_ATAPI:
-                /* check status of DMA engine */
-                host_stat = ap->ops->bmdma_status(ap);
-                VPRINTK("ata%u: host_stat 0x%X\n", ap->id, host_stat);
+        u8 status, host_stat = 0;
 
-                /* if it's not our irq... */
-                if (!(host_stat & ATA_DMA_INTR))
-                        goto idle_irq;
-
-                /* before we do anything else, clear DMA-Start bit */
-                ap->ops->bmdma_stop(qc);
+        VPRINTK("ata%u: protocol %d task_state %d\n",
+                ap->id, qc->tf.protocol, ap->hsm_task_state);
 
-                /* fall through */
-
-        case ATA_PROT_ATAPI_NODATA:
-        case ATA_PROT_NODATA:
-                /* check altstatus */
-                status = ata_altstatus(ap);
-                if (status & ATA_BUSY)
-                        goto idle_irq;
+        /* Check whether we are expecting interrupt in this state */
+        switch (ap->hsm_task_state) {
+        case HSM_ST_FIRST:
+                /* Some pre-ATAPI-4 devices assert INTRQ
+                 * at this state when ready to receive CDB.
+                 */
 
-                /* check main status, clearing INTRQ */
-                status = ata_chk_status(ap);
-                if (unlikely(status & ATA_BUSY))
+                /* Check the ATA_DFLAG_CDB_INTR flag is enough here.
+                 * The flag was turned on only for atapi devices.
+                 * No need to check is_atapi_taskfile(&qc->tf) again.
+                 */
+                if (!(qc->dev->flags & ATA_DFLAG_CDB_INTR))
                         goto idle_irq;
-                DPRINTK("ata%u: protocol %d (dev_stat 0x%X)\n",
-                        ap->id, qc->tf.protocol, status);
-
-                /* ack bmdma irq events */
-                ap->ops->irq_clear(ap);
-
-                /* complete taskfile transaction */
-                qc->err_mask |= ac_err_mask(status);
-                ata_qc_complete(qc);
                 break;
-
+        case HSM_ST_LAST:
+                if (qc->tf.protocol == ATA_PROT_DMA ||
+                    qc->tf.protocol == ATA_PROT_ATAPI_DMA) {
+                        /* check status of DMA engine */
+                        host_stat = ap->ops->bmdma_status(ap);
+                        VPRINTK("ata%u: host_stat 0x%X\n", ap->id, host_stat);
+
+                        /* if it's not our irq... */
+                        if (!(host_stat & ATA_DMA_INTR))
+                                goto idle_irq;
+
+                        /* before we do anything else, clear DMA-Start bit */
+                        ap->ops->bmdma_stop(qc);
+
+                        if (unlikely(host_stat & ATA_DMA_ERR)) {
+                                /* error when transfering data to/from memory */
+                                qc->err_mask |= AC_ERR_HOST_BUS;
+                                ap->hsm_task_state = HSM_ST_ERR;
+                        }
+                }
+                break;
+        case HSM_ST:
+                break;
         default:
                 goto idle_irq;
         }
 
+        /* check altstatus */
+        status = ata_altstatus(ap);
+        if (status & ATA_BUSY)
+                goto idle_irq;
+
+        /* check main status, clearing INTRQ */
+        status = ata_chk_status(ap);
+        if (unlikely(status & ATA_BUSY))
+                goto idle_irq;
+
+        /* ack bmdma irq events */
+        ap->ops->irq_clear(ap);
+
+        ata_hsm_move(ap, qc, status, 0);
         return 1;       /* irq handled */
 
 idle_irq:
@@ -4480,11 +4667,11 @@ irqreturn_t ata_interrupt (int irq, void *dev_instance, struct pt_regs *regs)
 
                 ap = host_set->ports[i];
                 if (ap &&
-                    !(ap->flags & (ATA_FLAG_DISABLED | ATA_FLAG_NOINTR))) {
+                    !(ap->flags & ATA_FLAG_DISABLED)) {
                         struct ata_queued_cmd *qc;
 
                         qc = ata_qc_from_tag(ap, ap->active_tag);
-                        if (qc && (!(qc->tf.ctl & ATA_NIEN)) &&
+                        if (qc && (!(qc->tf.flags & ATA_TFLAG_POLLING)) &&
                             (qc->flags & ATA_QCFLAG_ACTIVE))
                                 handled |= ata_host_intr(ap, qc);
                 }