TRAN_SETUP_PKT(9E)TRAN_SETUP_PKT(9E)NAME
tran_setup_pkt, tran_teardown_pkt, tran_pkt_constructor,
tran_pkt_destructor - SCSI HBA packet allocation and deallocation
SYNOPSIS
#include <sys/scsi/scsi.h>
struct scsi_pkt *prefix_tran_setup_pkt(struct scsi_pkt *pkt,
int (*callback) (caddr_t), caddr_t arg);
void prefix_tran_teardown_pkt(struct scsi_pkt *pkt);
int prefix_tran_pkt_constructor(struct scsi_pkt *pkt,
scsi_hba_tran_t *tranp, int kmflags);
void prefix_tran_pkt_destructor(struct scsi_pkt *pkt,
struct scsi_hba_tran_t *tranp);
INTERFACE LEVEL
Solaris architecture specific (Solaris DDI).
PARAMETERS
pkt
Pointer to the scsi_pkt(9S) structure.
flags
Flags for associating DMA resources with the packet.
callback
Pointer to either NULL_FUNC or SLEEP_FUNC.
arg
Always NULL.
kmflags
Either KM_SLEEP or KM_NOSLEEP.
DESCRIPTION
The tran_setup_pkt() and tran_destroy_pkt() vectors in the
scsi_hba_tran(9S) structure are alternatives to the tran_init_pkt() and
tran_destroy_pkt() entry points. They are initialized during the HBA
driver's attach(9E) and they are used when a target driver calls
scsi_init_pkt(9F) and scsi_destroy_pkt(9F).
tran_setup_pkt()
The tran_setup_pkt() vector is the entry point into the HBA which is
used to initialize HBA specific information in a scsi_pkt structure on
behalf of a SCSI target driver. All fields documented in scsi_pkt(9S)
are initialized.
If the HBA driver chose not to preallocate memory for pkt_cdbp and/or
pkt_scbp, it must allocate the requested memory at this time and point
pkt_cdbp and pkt_scbp to the allocated memory.
An HBA driver which provides a tran_setup_pkt entry point inspects the
pkt_numcookies and pkt_cookies fields at tran_start time to set up the
transfer. If pkt_numcookies is zero, there are no DMA resources associ‐
ated with this packet. If pkt_numcookies is not zero, it indicates the
number of DMA cookies that pkt_cookies points to.
The pkt_tgtlen field contains the length of the packet private area
pointed to by pkt_private, allocated on behalf of the SCSI target
driver.
The pkt_scblen field contains the length of the SCSI status completion
block pointed to by pkt_scbp. If the status length is greater than or
equal to sizeof (struct scsi_arq_status) and the auto_rqsensecapability
has been set, automatic request sense (ARS) is enabled for this packet.
If the status lengthislessthansizeof (struct scsi_arq_status), auto‐
matic request sense should be disabled for this pkt if the HBA driver
is capable of disabling ARQ on a per-packet basis.
The pkt_cdblen field contains the length of the SCSI command descriptor
block.
The callback argument indicates what the allocator routines should do
when resources are not available:
NULL_FUNC
Do not wait for resources. Return a NULL pointer.
SLEEP_FUNC
Wait indefinitely for resources.
tran_teardown_pkt()
The tran_teardown_pkt() is the entry point into the HBA that must free
all of the resources that were allocated to the scsi_pkt(9S) structure
during tran_setup_pkt().
tran_pkt_constructor()tran_pkt_destructor()
When using tran_pkt_setup() and tran_pkt_teardown(), tran_pkt_construc‐
tor() and tran_pkt_destructor() are additional optional entry points
that perform the actions of a constructor and destructor. The con‐
structor is called after the following fields in the scsi_pkt structure
have been initialized:
o pkt_address
o pkt_ha_private
o pkt_cdbp
o pkt_private
o pkt_scbp
o pkt_cdblen
o pkt_tgtlen
o pkt_scblen
Allocating and freeing a DMA handle are examples of something that
could be done in the constructor and destructor. See kmem_cache_cre‐
ate(9F) for additional restrictions on what actions can be performed in
a constructor and destructor.
HBA drivers that implement tran_setup_pkt() must signal scsi_pkt(9S)
completion by calling scsi_hba_pkt_comp(9F). Direct use of the
scsi_pkt pkt_comp field is not permitted and results in undefined
behavior.
RETURN VALUEStran_setup_pkt() must return zero on success, and -1 on failure.
SEE ALSOattach(9E), tran_sync_pkt(9E), bioerror(9F), ddi_dma_buf_bind_han‐
dle(9F), kmem_cache_create(9F), scsi_alloc_consistent_buf(9F),
scsi_destroy_pkt(9F), scsi_hba_attach(9F), scsi_hba_pkt_alloc(9F),
scsi_hba_pkt_comp(9F), scsi_hba_pkt_free(9F), scsi_init_pkt(9F),
buf(9S), scsi_address(9S), scsi_hba_tran(9S), scsi_pkt(9S)
Writing Device Drivers
Jan 29, 2009 TRAN_SETUP_PKT(9E)
