NAME¶
sym
—
NCR/Symbios/LSI Logic 53C8XX PCI SCSI host adapter
driver
SYNOPSIS¶
To compile this driver into the kernel, place the following lines in your kernel
configuration file:
device pci
device scbus
device sym
To disable PCI parity checking (needed for broken bridges):
options SYM_SETUP_PCI_PARITY=<boolean>
To control driver probing against HVD buses:
options SYM_SETUP_SCSI_DIFF=<bit
combination>
To control chip attachment balancing between the ncr driver and this driver:
options SYM_SETUP_LP_PROBE_MAP=<bit
combination>
Alternatively, to load the driver as a module at boot time, place the following
line in
loader.conf(5):
DESCRIPTION¶
This driver provides support for the Symbios/LSI Logic 53C8XX PCI SCSI
controllers.
Driver features include support for wide SCSI busses and fast10, fast20, fast40
and fast80-dt synchronous data transfers depending on controller capabilities.
It also provides generic SCSI features such as tagged command queueing and
auto-request sense. This driver is configured by default for a maximum of 446
outstanding commands per bus, 8 LUNs per target and 64 tagged tasks per LUN.
These numbers are not so much limited by design as they are considered
reasonable values for current SCSI technology. These values can be increased
by changing appropriate constants in driver header files (not recommended).
This driver supports the entire Symbios 53C8XX family of PCI SCSI controllers.
It also offers the advantage of architectural improvements available only with
newer chips.
sym
notably handles phase mismatch from
SCRIPTS for the 53C896, 53C895A, and 53C1010 cores. As a result, it guarantees
that no more than 1 interrupt per IO completion is delivered to the CPU, and
that the SCRIPTS processor is never stalled waiting for CPU attention in
normal situations.
sym
also uses LOAD/STORE SCRIPTS instructions
for chips that support it. Only the early 810, 815 and 825 NCR chips do not
support LOAD/STORE. Use of LOAD/STORE instead of MEMORY MOVE allows SCRIPTS to
access IO registers internal to the chip (no external PCI cycles). As a
result, the driver guarantees that no PCI self-mastering will occur for chips
that support LOAD/STORE.
LOAD/STORE instructions are also faster than MEMORY MOVE because they do not
involve the chip DMA FIFO and are coded on 2 DWORDs instead of 3.
For the early NCR 810, 815 and 825 chips, the driver uses a separate SCRIPTS set
that uses MEMORY MOVE instructions for data movements. This is because
LOAD/STORE are not supported by these chips.
HVD/LVD capable controllers (895, 895A, 896, and 897) report the actual bus mode
in the STEST4 chip IO registers. This feature allows the driver to safely
probe against bus mode and to set up the chip accordingly. By default the
driver only supports HVD for these chips. For other chips that can support HVD
but not LVD, the driver has to probe implementation dependent registers (GPIO)
in order to detect HVD bus mode. Only HVD implementations that conform with
Symbios Logic recommendations can be detected by the driver. When the
SYM_SETUP_SCSI_DIFF kernel option is assigned
a value of 1, the driver will also probe against HVD for 825a, 875, 876 and
885 chips, assuming Symbios Logic compatible implementation of HVD.
When the
SYM_SETUP_PCI_PARITY is assigned a
value of 0, the driver will not enable PCI parity checking for 53C8XX devices.
PCI parity checking should not be an option for PCI SCSI controllers, but some
systems have been reported to fail using 53C8XX chips, due to spurious or
permanent PCI parity errors detected. This option is supplied for convenience
but it is neither recommended nor supported.
The generic
ncr(4) driver also supports SYM53C8XX
based PCI SCSI controllers, except for the SYM53C1010, which is only supported
by the
sym
driver.
By default, when both the
ncr(4) and
sym
drivers are configured, the
sym
driver takes precedence over the
ncr(4) driver. The user can indicate a balancing
of chip types between the two drivers by defining the
SYM_SETUP_LP_PROBE_MAP kernel configuration
option as follows:
Bit |
Devices to be attached by ncr instead |
0x01 |
53C810a, 53C860 |
0x02 |
53C825a, 53C875, 53C876, 53C885, 53C895 |
0x04 |
53C895a, 53C896, 53C897, 53C1510d |
0x40 |
53C810, 53C815, 53C825 |
For example, if
SYM_SETUP_LP_PROBE_MAP is
supplied with the value 0x41, the
ncr(4) driver
will attach to 53C810, 53C815, 53C825, 53C810a, and 53C860 based controllers,
and the
sym
driver will attach to all other
53C8XX based controllers.
When only the
sym
driver is configured, the
SYM_SETUP_LP_PROBE_MAP option has no effect.
Thus, in this case, the
sym
driver will
attach all 53C8XX based controllers present in the system.
This driver offers other options that are not currently exported to the user.
They are defined and documented in the
sym_conf.h driver file. Changing these
options is not recommended unless absolutely necessary. Some of these options
are planned to be exported through
sysctl(3) or
an equivalent mechanism in a future driver releases and therefore, no
compatibility is guaranteed.
At initialization, the driver tries to detect and read user settings from
controller NVRAM. The Symbios/Logic NVRAM layout and the Tekram NVRAM layout
are currently supported. If the reading of the NVRAM succeeds, the following
settings are taken into account and reported to CAM:
Host settings |
Symbios |
Tekram |
SCSI parity checking |
Y |
N |
Host SCSI ident |
Y |
Y |
Verbose messages |
Y |
N |
Scan targets hi-lo |
Y |
N |
Avoid SCSI bus reset |
Y |
N |
Device settings |
Symbios |
Tekram |
Synchronous period |
Y |
Y |
SCSI bus width |
Y |
Y |
Queue tag enable |
Y |
Y |
Number of tags |
NA |
Y |
Disconnect enable |
Y |
Y |
Scan at boot time |
Y |
N |
Scan LUN |
Y |
N |
Devices that are configured as disabled for 'scan' in the NVRAM are not reported
to CAM at system start-up. They can be discovered later using the
‘
camcontrol rescan
’ command.
The table below summarizes the main features and capabilities of the
NCR/Symbios/LSI Logic 53C8XX family of PCI SCSI controllers.
Chip |
Sync |
Width |
SRAM |
PCI64 |
Supported |
sym53c810 |
10MHz |
8Bit |
N |
N |
Y |
sym53c810a |
10MHz |
8Bit |
N |
N |
Y |
sym53c815 |
10MHz |
8Bit |
N |
N |
Y |
sym53c825 |
10MHz |
16Bit |
N |
N |
Y |
sym53c825a |
10MHz |
16Bit |
4KB |
N |
Y |
sym53c860 |
20MHz |
8Bit |
N |
N |
Y |
sym53c875 |
20MHz |
16Bit |
4KB |
N |
Y |
sym53c876 |
20MHz |
16Bit |
4KB |
N |
Y |
sym53c885 |
20MHz |
16Bit |
4KB |
N |
Y |
sym53c895 |
40MHz |
16Bit |
4KB |
N |
Y |
sym53c895A |
40MHz |
16Bit |
8KB |
N |
Y |
sym53c896 |
40MHz |
16Bit |
8KB |
Y |
Y |
sym53c897 |
40MHz |
16Bit |
8KB |
Y |
Y |
sym53c1510D |
40MHz |
16Bit |
4KB |
Y |
Y |
sym53c1010 |
80MHz |
16Bit |
8KB |
Y |
Y |
HARDWARE¶
The
sym
driver provides support for the
following Symbios/LSI Logic PCI SCSI controllers:
- 53C810
- 53C810A
- 53C815
- 53C825
- 53C825A
- 53C860
- 53C875
- 53C876
- 53C895
- 53C895A
- 53C896
- 53C897
- 53C1000
- 53C1000R
- 53C1010-33
- 53C1010-66
- 53C1510D
The SCSI controllers supported by
sym
can be
either embedded on a motherboard, or on one of the following add-on boards:
- ASUS SC-200, SC-896
- Data Technology DTC3130 (all variants)
- DawiControl DC2976UW
- Diamond FirePort (all)
- I-O DATA SC-UPCI (PC-98)
- Logitec LHA-521UA (PC-98)
- NCR cards (all)
- Symbios cards (all)
- Tekram DC390W, 390U, 390F, 390U2B, 390U2W, 390U3D, and 390U3W
- Tyan S1365
MISC¶
The DEC KZPCA-AA is a rebadged SYM8952U.
SEE ALSO¶
cd(4),
da(4),
ncr(4),
sa(4),
scsi(4),
camcontrol(8)
HISTORY¶
The
sym
driver appeared in
FreeBSD 4.0.
AUTHORS¶
The
sym
driver was written by
Gerard Roudier and is derived from the
Linux sym53c8xx driver from the same author. The sym53c8xx driver is derived
from the ncr53c8xx driver, which was ported from the
FreeBSD ncr(4) driver to
Linux-1.2.13. The original
ncr(4) driver was
written for
386BSD and
FreeBSD
by
Wolfgang Stanglmeier and
Stefan Esser.
BUGS¶
No known bugs.