SCSI_PKT(9S) Data Structures for Drivers SCSI_PKT(9S)
NAME
scsi_pkt - SCSI packet structure
SYNOPSIS
#include <sys/scsi/scsi.h>
INTERFACE LEVEL
illumos DDI specific (illumos DDI).
DESCRIPTION
A
scsi_pkt structure defines the packet that is allocated by
scsi_init_pkt(9F). The target driver fills in some information and passes
it to
scsi_transport(9F) for execution on the target. The host bus
adapter (
HBA) fills in other information as the command is processed.
When the command completes or can be taken no further, the completion
function specified in the packet is called with a pointer to the packet
as its argument. From fields within the packet, the target driver can
determine the success or failure of the command.
STRUCTURE MEMBERS
opaque_t pkt_ha_private; /* private data for
host adapter */
struct scsi_address pkt_address; /* destination packet */
opaque_t pkt_private; /* private data
for target driver */
void (*pkt_comp)(struct scsi_pkt *); /* callback */
uint_t pkt_flags; /* flags */
int pkt_time; /* time allotted to
complete command */
uchar_t *pkt_scbp; /* pointer to
status block */
uchar_t *pkt_cdbp; /* pointer to
command block */
ssize_t pkt_resid; /* number of bytes
not transferred */
uint_t pkt_state; /* state of command */
uint_t pkt_statistics; /* statistics */
uchar_t pkt_reason; /* reason completion
called */
uint_t pkt_cdblen; /* length of pkt_cdbp */
uint_t pkt_scdblen; /* length of pkt_scbp */
uint_t pkt_tgtlen; /* length of pkt_private */
uint_t pkt_numcookies; /* number of DMA cookies */
ddi_dma_cookie_t *pkt_cookies; /* array of DMA cookies */
uint_t pkt_dma_flags; /* DMA flags */
pkt_ha_private Opaque pointer that the HBA uses to reference a private
data structure that transfers
scsi_pkt requests.
pkt_address Initialized by
scsi_init_pkt(9F),
pkt_address records
the intended route and the recipient of a request.
pkt_private Reserved for the use of the target driver,
pkt_private is not changed by the HBA driver.
pkt_comp Specifies the command completion callback routine. When
the host adapter driver has gone as far as it can in
transporting a command to a
SCSI target, and the
command has either run to completion or can go no
further for some other reason, the host adapter driver
calls the function pointed to by this field and passes
a pointer to the packet as argument. The callback
routine itself is called from interrupt context and
must not sleep or call any function that might sleep.
pkt_flags Provides additional information about how the target
driver expects the command to be executed. See
pkt_flag Definitions.
pkt_time Set by the target driver to represent the maximum time
allowed in seconds for this command to complete.
Timeout starts when the command is transmitted on the
SCSI bus. The
pkt_time may be
0 if no timeout is
required.
pkt_scbp Points to either a struct
scsi_status(9S) or, if
auto- rqsense is enabled and
pkt_state includes
STATE_ARQ_DONE, a struct
scsi_arq_status. If
scsi_status is returned, the
SCSI status byte resulting
from the requested command is available. If
scsi_arq_status(9S) is returned, the sense information
is also available.
pkt_cdbp Points to a kernel-addressable buffer with a length
specified by a call to the proper resource allocation
routine,
scsi_init_pkt(9F).
pkt_resid Contains a residual count, either the number of data
bytes that have not been transferred
(
scsi_transport(9F)) or the number of data bytes for
which DMA resources could not be allocated
scsi_init_pkt(9F). In the latter case, partial DMA
resources can be allocated only if
scsi_init_pkt(9F) is
called with the
PKT_DMA_PARTIAL flag.
pkt_state Has bit positions that represent the six most important
states that a
SCSI command can go through. See
pkt_state Definitions.
pkt_statistics Maintains some transport-related statistics. See
pkt_statistics Definitions.
pkt_reason Contains a completion code that indicates why the
pkt_comp function was called. See
pkt_reason Definitions.
pkt_cdblen Length of buffer pointed to by
pkt_cdbp. See
tran_setup_pkt.
pkt_scblen Length of buffer pointed to by
pkt_scbp. See
tran_setup_pkt.
pkt_tgtlen Length of buffer pointed to by
pkt_private. See
tran_setup_pkt.
pkt_numcookies Length
pkt_cookies array. See
tran_setup_pkt.
pkt_cookies Array of DMA cookies. See
tran_setup_pkt.
pkt_dma_flags DMA flags used, such as
DDI_DMA_READ and
DDI_DMA_WRITE.
See
tran_setup_pkt.
The host adapter driver will update the
pkt_resid,
pkt_reason,
pkt_state,
and
pkt_statistics fields.
pkt_flags Definitions
The appropriate definitions for the structure member
pkt_flags are:
FLAG_NOINTR Run command with no command completion
callback. Command is complete upon return
from
scsi_transport(9F).
FLAG_NODISCON Run command without disconnects.
FLAG_NOPARITY Run command without parity checking.
FLAG_HTAG Run command as the head-of-queue-tagged
command.
FLAG_OTAG Run command as an ordered-queue-tagged
command.
FLAG_STAG Run command as a simple-queue-tagged
command.
FLAG_SENSING Indicates a request sense command.
FLAG_HEAD Place command at the head of the queue.
FLAG_RENEGOTIATE_WIDE_SYNC Before transporting this command, the host
adapter should initiate the renegotiation
of wide mode and synchronous transfer
speed. Normally, the HBA driver manages
negotiations but under certain conditions
forcing a renegotiation is appropriate.
Renegotiation is recommended before Request
Sense and Inquiry commands. Refer to the
SCSI 2 standard, sections 6.6.21 and
6.6.23.
This flag should not be set for every
packet as this will severely impact
performance.
pkt_reason Definitions
The appropriate definitions for the structure member
pkt_reason are:
CMD_CMPLT No transport errors; normal completion.
CMD_INCOMPLETE Transport stopped with abnormal state.
CMD_DMA_DERR DMAd irection error.
CMD_TRAN_ERR Unspecified transport error.
CMD_RESET SCSI bus reset destroyed command.
CMD_ABORTED Command transport aborted on request.
CMD_TIMEOUT Command timed out.
CMD_DATA_OVR Data overrun.
CMD_CMD_OVR Command overrun.
CMD_STS_OVR Status overrun.
CMD_BADMSG Message not command complete.
CMD_NOMSGOUT Target refused to go to message out phase.
CMD_XID_FAIL Extended identify message rejected.
CMD_IDE_FAIL "Initiator Detected Error" message rejected.
CMD_ABORT_FAIL Abort message rejected.
CMD_REJECT_FAIL Reject message rejected.
CMD_NOP_FAIL "No Operation" message rejected.
CMD_PER_FAIL "Message Parity Error" message rejected.
CMD_BDR_FAIL "Bus Device Reset" message rejected.
CMD_ID_FAIL Identify message rejected.
CMD_UNX_BUS_FREE Unexpected bus free phase.
CMD_TAG_REJECT Target rejected the tag message.
CMD_DEV_GONE The device has been removed.
pkt_state Definitions The appropriate definitions for the structure member
pkt_state are:
STATE_GOT_BUS Bus arbitration succeeded.
STATE_GOT_TARGET Target successfully selected.
STATE_SENT_CMD Command successfully sent.
STATE_XFERRED_DATA Data transfer took place.
STATE_GOT_STATUS Status received.
STATE_ARQ_DONE The command resulted in a check condition and the
host adapter driver executed an automatic request
sense command.
STATE_XARQ_DONE The command requested in extra sense data using a
PKT_XARQ flag got a check condition. The host
adapter driver was able to successfully request and
return this. The
scsi_pkt.pkt_scbp->sts_rqpkt_resid returns the sense data residual based on the
statuslen parameter of the
scsi_init_pkt(9F) call.
The sense data begins at
scsi_pkt.pkt_scbp->sts_sensedata.
pkt_statistics Definitions The definitions that are appropriate for the structure member
pkt_statistics are:
STAT_DISCON Device disconnect.
STAT_SYNC Command did a synchronous data transfer.
STAT_PERR SCSI parity error.
STAT_BUS_RESET Bus reset.
STAT_DEV_RESET Device reset.
STAT_ABORTED Command was aborted.
STAT_TIMEOUT Command timed out.
SEE ALSO
tran_init_pkt(9E),
tran_setup_pkt(9E),
scsi_hba_pkt_comp(9F),
scsi_init_pkt(9F),
scsi_transport(9F),
scsi_arq_status(9S),
scsi_status(9S) Writing Device DriversNOTES
HBA drivers should signal
scsi_pkt completion by calling
scsi_hba_pkt_comp(9F). This is mandatory for HBA drivers that implement
tran_setup_pkt(9E). Failure to comply results in undefined behavior.
January 11, 2009
SCSI_PKT(9S)