The scsi_ifsetcap() function is used by target drivers to set the
capabilities of the host adapter driver. The cap pointer is a
name-value pair identified by a null-terminated character string and the
integer value of the cap. The current value of the capability can be
retrieved with the scsi_ifgetcap() function. If the whom value
is 0, all target drivers are affected. Otherwise, the
scsi_address structure pointed to by ap is the only target that
is affected.
The driver should confirm that scsi_ifsetcap() and
scsi_ifsetcap() functions are called with a cap that points to
a capability which is supported by the device.
The following capabilities have been defined:
dma-max
Maximum dma transfer size that is supported by the
host adapter.
dma-max-arch
Maximum
dma transfer size that is supported by
system. Takes the host adapter and system architecture into account. This is
useful for target drivers which do not support partial
DMAs on systems
which do not have an
IOMMU. In this case, the
DMA can also be
limited by the host adapters "scatter/gather" list constraints.
The "dma-max-arch" capability can not be set. It
is implemented with this command and does not rely on a
tran_getcap(9E) response from the HBA.
msg-out
Message out capability that is supported by the host
adapter: 0 disables, 1 enables.
disconnect
Disconnect capability that is supported by the host
adapter: 0 disables, 1 enables.
synchronous
Synchronous data transfer capability that is supported by
the host adapter: 0 disables, 1 enables.
wide-xfer
Wide transfer capability that is supported by the host
adapter: 0 disables, 1 enables.
parity
Parity checking capability that is supported by host
adapter: 0 disables, 1 enables.
initiator-id
Host bus address that is returned.
untagged-qing
Host adapter capability that supports internal queueing
of commands without tagged queueing: 0 disables, 1
enables.
tagged-qing
Host adapter capability that supports queuing: 0
disables, 1 enables.
auto-rqsense
Host adapter capability that supports auto request sense
on check conditions: 0 disables, 1 enables.
sector-size
Capability that is set by the target driver to inform the
HBA of the granularity, in bytes, of the
DMA breakup. The
HBA DMA attributes structure is set to reflect the byte total of
this setting. See
ddi_dma_attr(9S). The
sector-size should be
set to the size of the physical disk sector. The capability defaults to 512
bytes.
total-sectors
Capability that is set by the target driver to inform the
HBA of the total number of sectors on the device returned by the
SCSI get capacity command. This capability must be set
before the target driver ``gets'' the geometry capability.
geometry
Capability that returns the
HBA geometry of a
target disk. The target driver sets the
total-sectors capability before
``getting'' the geometry capability. The geometry is returned as a 32-bit
value. The upper 16 bits represent the number of heads per cylinder. The lower
16 bits represent the number of sectors per track. The geometry capability
cannot be ``set''.
If geometry is not relevant or appropriate for the target disk,
scsi_ifgetcap() can return -1 to indicate that the geometry is
not defined. For example, if the HBA BIOS supports Logical Block
Addressing for the target disk, scsi_ifgetcap() returns -1.
Attempts to retrieve the "virtual geometry" from the target
driver, such as the DKIOCG_VIRTGEOM ioctl, will fail. See
dkio(4I) for more information about DKIOCG_VIRTGEOM.
reset-notification
Host adapter capability that supports bus reset
notification:
0 disables,
1 enables. See
scsi_reset_notify(9F).
linked-cmds
Host adapter capability that supports linked commands:
0 disables, 1 enables.
qfull-retries
Capability that enables or disables QUEUE
FULL handling. If 0, the HBA will not retry a command
when a QUEUE FULL status is returned. If the value is greater
than 0, the HBA driver retries the command a specified number of
times at an interval determined by the qfull-retry-interval. The range
for qfull-retries is 0-255.
qfull-retry-interval
Capability that sets the retry interval in milliseconds
(ms) for commands completed with a QUEUE FULL status. The
range for qfull-retry-intervals is 0-1000 ms.
lun-reset
Capability that is created with a value of zero by
HBA drivers that support the
RESET_LUN flag in the
tran_reset(9E) function. If it exists, the
lun-reset value can
be set to
1 by target drivers to allow the use of
LOGICAL UNIT
RESET on a specific target instance. If
lun-reset does not exist or
has a value of zero,
scsi_reset(9F) is prevented from passing the
RESET_LUN flag to
tran_reset() function of the
HBA
driver. If
lun-reset exists and has a value of
1, the
tran_reset() function of the
HBA driver can be called with the
RESET_LUN flag.
interconnect-type
Capability held in the tran_interconnect_type
element of struct scsi_hba_tran that indicates the HBA transport
interconnect type . The integer value of the interconnect type of the
transport is defined in the services.h header file.
max-cdb-length
Host adapter capability of the maximum supported
CDB (Command Descriptor Block) length. The target driver asks for the
capability at attach time. If the
HBA driver supports the capability,
the maximum length of the
CDB is returned in bytes. The target driver
can then use that value to determine which
CDB is used for the
HBA.
If the HBA driver does not support the
max-cdb-length capability, the default value of the target driver is
used for the CDB determination.