sbus(4) File Formats sbus(4)NAMEsbus - configuration files for SBus device drivers
DESCRIPTION
The SBus is a geographically addressed peripheral bus present on many
SPARC hardware platforms. SBus devices are self-identifying — that is
to say the SBus card itself provides information to the system so that
it can identify the device driver that needs to be used. The device
usually provides additional information to the system in the form of
name-value pairs that can be retrieved using the DDI property inter‐
faces. See ddi_prop_op(9F) for details.
The information is usually derived from a small Forth program stored in
the FCode PROM on the card, so driver configuration files should be
completely unnecessary for these devices. However, on some occasions,
drivers for SBus devices may need to use driver configuration files to
augment the information provided by the SBus card. See driver.conf(4)
for further details.
When they are needed, configuration files for SBus device drivers
should identify the parent bus driver implicitly using the class key‐
word. This removes the dependency on the particular bus driver
involved since this may be named differently on different platforms.
All bus drivers of class sbus recognise the following properties:
reg An arbitrary length array where each element of the
array consists of a 3-tuple of integers. Each array
element describes a logically contiguous mappable
resource on the SBus.
The first integer of each tuple specifies the slot num‐
ber the card is plugged into. The second integer of
each 3-tuple specifies the offset in the slot address
space identified by the first element. The third inte‐
ger of each 3-tuple specifies the size in bytes of the
mappable resource.
The driver can refer to the elements of this array by
index, and construct kernel mappings to these addresses
using ddi_map_regs(9F). The index into the array is
passed as the rnumber argument of ddi_map_regs().
You can use the ddi_get* and ddi_put* family of func‐
tions to access register space from a high-level inter‐
rupt context.
interrupts An arbitrary length array where each element of the
array consists of a single integer. Each array element
describes a possible SBus interrupt level that the
device might generate.
The driver can refer to the elements of this array by
index, and register interrupt handlers with the system
using ddi_add_intr(9F). The index into the array is
passed as the inumber argument of ddi_add_intr().
registers An arbitrary length array where each element of the
array consists of a 3-tuple of integers. Each array
element describes a logically contiguous mappable
resource on the SBus.
The first integer of each tuple should be set to −1,
specifying that any SBus slot may be matched. The sec‐
ond integer of each 3-tuple specifies the offset in the
slot address space identified by the first element.
The third integer of each 3-tuple specifies the size in
bytes of the mappable resoure.
The registers property can only be used to augment an
incompletely specified reg property with information
from a driver configuration file. It may only be speci‐
fied in a driver configuration file.
All SBus devices must provide reg properties to the system. The first
two integer elements of the reg property are used to construct the
address part of the device name under /devices.
Only devices that generate interrupts need to provide interrupts prop‐
erties.
Occasionally, it may be necessary to override or augment the configura‐
tion information supplied by the SBus device. This can be achieved by
writing a driver configuration file that describes a prototype device
information (devinfo) node specification, containing the additional
properties required.
For the system to merge the information, certain conditions must be
met. First, the name property must be the same. Second, either the
first two integers (slot number and offset) of the two reg properties
must be the same, or the second integer (offset) of the reg and regis‐
ters properties must be the same.
In the event that the SBus card has no reg property at all, the self-
identifying information cannot be used, so all the details of the card
must be specified in a driver configuration file.
EXAMPLES
Example 1: A sample configuration file.
Here is a configuration file for an SBus card called SUNW,netboard. The
card already has a simple FCode PROM that creates name and reg proper‐
ties, and will have a complete set of properties for normal use once
the driver and firmware is complete.
In this example, we want to augment the properties given to us by the
firmware. We use the same name property, and use the registers property
to match the firmware reg property. That way we don't have to worry
about which slot the card is really plugged into.
We want to add an interrupts property while we are developing the
firmware and driver so that we can start to experiment with interrupts.
The device can generate interrupts at SBus level 3. Additionally, we
want to set a debug-level property to 4.
#
# Copyright (c) 1992, by Sun Microsystems, Inc.
#ident "@(#)SUNW,netboard.conf 1.4 92/03/10 SMI"
#
name="SUNW,netboard" class="sbus"
registers=-1,0x40000,64,-1,0x80000,1024
interrupts=3 debug-level=4;
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Architecture │SPARC │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOdriver.conf(4), attributes(5), ddi_add_intr(9F), ddi_map_regs(9F),
ddi_prop_op(9F)
Writing Device Drivers
WARNINGS
The wildcarding mechanism of the registers property matches every
instance of the particular device attached to the system.
This may not always be what is wanted.
SunOS 5.10 31 Dec 1996 sbus(4)
