in libata-sff.c [970:1216]
int ata_sff_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc,
u8 status, int in_wq)
{
struct ata_link *link = qc->dev->link;
struct ata_eh_info *ehi = &link->eh_info;
int poll_next;
lockdep_assert_held(ap->lock);
WARN_ON_ONCE((qc->flags & ATA_QCFLAG_ACTIVE) == 0);
/* Make sure ata_sff_qc_issue() 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_ONCE(in_wq != ata_hsm_ok_in_wq(ap, qc));
fsm_start:
trace_ata_sff_hsm_state(qc, 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_DRQ) == 0)) {
/* handle BSY=0, DRQ=0 as error */
if (likely(status & (ATA_ERR | ATA_DF)))
/* device stops HSM for abort/error */
qc->err_mask |= AC_ERR_DEV;
else {
/* HSM violation. Let EH handle this */
ata_ehi_push_desc(ehi,
"ST_FIRST: !(DRQ|ERR|DF)");
qc->err_mask |= AC_ERR_HSM;
}
ap->hsm_task_state = HSM_ST_ERR;
goto fsm_start;
}
/* 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))) {
/* Some ATAPI tape drives forget to clear the ERR bit
* when doing the next command (mostly request sense).
* We ignore ERR here to workaround and proceed sending
* the CDB.
*/
if (!(qc->dev->horkage & ATA_HORKAGE_STUCK_ERR)) {
ata_ehi_push_desc(ehi, "ST_FIRST: "
"DRQ=1 with device error, "
"dev_stat 0x%X", status);
qc->err_mask |= AC_ERR_HSM;
ap->hsm_task_state = HSM_ST_ERR;
goto fsm_start;
}
}
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);
} else
/* send CDB */
atapi_send_cdb(ap, qc);
/* if polling, ata_sff_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 == ATAPI_PROT_PIO) {
/* ATAPI PIO protocol */
if ((status & ATA_DRQ) == 0) {
/* No more data to transfer or device error.
* Device error will be tagged in HSM_ST_LAST.
*/
ap->hsm_task_state = HSM_ST_LAST;
goto fsm_start;
}
/* 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))) {
ata_ehi_push_desc(ehi, "ST-ATAPI: "
"DRQ=1 with device error, "
"dev_stat 0x%X", status);
qc->err_mask |= AC_ERR_HSM;
ap->hsm_task_state = HSM_ST_ERR;
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 */
if (likely(status & (ATA_ERR | ATA_DF))) {
/* device stops HSM for abort/error */
qc->err_mask |= AC_ERR_DEV;
/* If diagnostic failed and this is
* IDENTIFY, it's likely a phantom
* device. Mark hint.
*/
if (qc->dev->horkage &
ATA_HORKAGE_DIAGNOSTIC)
qc->err_mask |=
AC_ERR_NODEV_HINT;
} else {
/* HSM violation. Let EH handle this.
* Phantom devices also trigger this
* condition. Mark hint.
*/
ata_ehi_push_desc(ehi, "ST-ATA: "
"DRQ=0 without device error, "
"dev_stat 0x%X", status);
qc->err_mask |= AC_ERR_HSM |
AC_ERR_NODEV_HINT;
}
ap->hsm_task_state = HSM_ST_ERR;
goto fsm_start;
}
/* 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);
status = ata_wait_idle(ap);
}
if (status & (ATA_BUSY | ATA_DRQ)) {
ata_ehi_push_desc(ehi, "ST-ATA: "
"BUSY|DRQ persists on ERR|DF, "
"dev_stat 0x%X", status);
qc->err_mask |= AC_ERR_HSM;
}
/* There are oddball controllers with
* status register stuck at 0x7f and
* lbal/m/h at zero which makes it
* pass all other presence detection
* mechanisms we have. Set NODEV_HINT
* for it. Kernel bz#7241.
*/
if (status == 0x7f)
qc->err_mask |= AC_ERR_NODEV_HINT;
/* 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 */
status = ata_wait_idle(ap);
goto fsm_start;
}
}
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 */
trace_ata_sff_hsm_command_complete(qc, status);
WARN_ON_ONCE(qc->err_mask & (AC_ERR_DEV | AC_ERR_HSM));
ap->hsm_task_state = HSM_ST_IDLE;
/* complete taskfile transaction */
ata_hsm_qc_complete(qc, in_wq);
poll_next = 0;
break;
case HSM_ST_ERR:
ap->hsm_task_state = HSM_ST_IDLE;
/* complete taskfile transaction */
ata_hsm_qc_complete(qc, in_wq);
poll_next = 0;
break;
default:
poll_next = 0;
WARN(true, "ata%d: SFF host state machine in invalid state %d",
ap->print_id, ap->hsm_task_state);
}
return poll_next;
}