illumos: manual page: scsi

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;
struct scsi_address pkt_address;
opaque_t pkt_private;
void (*pkt_comp)(struct scsi_pkt *);
uint_t pkt_flags;
int pkt_time;
uchar_t *pkt_scbp;
uchar_t *pkt_cdbp;
ssize_t pkt_resid;
uint_t pkt_state;
uint_t pkt_statistics;
uchar_t pkt_reason;
uint_t pkt_cdblen;
uint_t pkt_scblen;
uint_t pkt_tgtlen;
uint_t pkt_numcookies;
ddi_dma_cookie_t *pkt_cookies;
uint_t pkt_dma_flags;

These members are described here:

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_flags 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 zero
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(9S). If scsi_status(9S) 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 by scsi_transport(9F) or the number of
data bytes for which DMA resources could not be allocated by
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. Se tran_setup_pkt(9E).

pkt_scblen
Length of buffer pointed to by pkt_scbp. See tran_setup_pkt(9E).

pkt_tgtlen
Length of buffer pointed to by pkt_private. See
tran_setup_pkt(9E).

pkt_numcookies
Length of pkt_cookies array. See tran_setup_pkt(9E).

pkt_cookies
Array of DMA cookies. See tran_setup_pkt(9E).

pkt_dma_flags
DMA flags used, such as DDI_DMA_READ and DDI_DMA_WRITE. See
tran_setup_pkt(9E).

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
DMA direction 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.

NOTES