sym(4)

NAME

sym - NCR/Symbios/LSI Logic 53C8XX PCI SCSI host adapter

driver

SYNOPSIS

For any number of cards:
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>

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 con

figured 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 ap

propriate 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 im

provements
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 ac

cess 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 be

cause they do
not involve the chip DMA FIFO and are coded on 2 DWORDs in

stead 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 al

lows the driver
to safely probe against bus mode and to set up the chip ac

cordingly. 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 recommenda

tions 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 par

ity 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 config

ured, 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 fol

lows:

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 at

tach all 53C8XX
based controllers present in the system.

This driver offers other options that are not currently ex

ported 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 there

fore, 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 capabili

ties 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 Sym

bios/LSI Logic PCI
SCSI controllers:

+o 53C810
+o 53C810A
+o 53C815
+o 53C825
+o 53C825A
+o 53C860
+o 53C875
+o 53C876
+o 53C895
+o 53C895A
+o 53C896
+o 53C897
+o 53C1000
+o 53C1000R
+o 53C1010-33
+o 53C1010-66
+o 53C1510D

The SCSI controllers supported by sym can be either embedded

on a motherboard, or on one of the following add-on boards:

+o ASUS SC-200, SC-896
+o Data Technology DTC3130 (all variants)
+o DawiControl DC2976UW
+o Diamond FirePort (all)
+o I-O DATA SC-UPCI (PC-98)
+o Logitec LHA-521UA (PC-98)
+o NCR cards (all)
+o Symbios cards (all)
+o Tekram DC390W, 390U, 390F, 390U2B, 390U2W, 390U3D, and

390U3W
+o 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.

BSD August 19, 2004

BSD