sysbus(4)							   File Formats 							 sysbus(4)

NAME

       sysbus, isa - device tree properties for ISA bus device drivers

DESCRIPTION

       Solaris	for  x86 supports  the ISA bus as the system bus. Drivers for devices on this buse use the device tree built by the booting system
       to retrieve the necessary system resources used by the driver. These resources include device I/O port addresses, any  interrupt  capabili-
       ties  that the device can have, any DMA channels it can require, and any memory-mapped addresses it can occupy.

       Configuration  files  for ISA device drivers are only necessary to describe properties used by a particular driver that are not part of the
       standard properties found in the device tree. See driver.conf(4) for further details of configuration file syntax.

       The ISA nexus drivers all belong to class sysbus. All bus drivers of class sysbus recognize the following properties:

       interrupts      An arbitrary-length array where each element of the array represents a hardware interrupt (IRQ) that is used by the device.
		       In general, this array only has one entry unless a particular device uses more than one IRQ.

		       Solaris defaults all ISA interrupts to IPL 5.  This interrupt priority can be overridden by placing an interrupt-priorities
		       property in a .conf file for the driver. Each entry in the array of  integers  for  the	interrupt-priorities  property	is
		       matched	one-to-one  with  the  elements in the interrupts property to specify the IPL value that is used by the system for
		       this interrupt in this driver. This is the priority that this device's interrupt handler receives relative to the interrupt
		       handlers  of other drivers.  The priority is an integer from  1 to 16. Generally, disks are assigned a priority of 5, while
		       mice and printers are lower, and serial communication devices are higher, typically 7. 10 is reserved  by  the  system  and
		       must  not  be  used.   Priorities  11  and  greater  are  high  level  priorities  and  are  generally not recommended (see
		       ddi_intr_hilevel(9F)).

		       The driver can refer to the elements of this array by index using ddi_add_intr(9F). The index into the array is	passed	as
		       the  inumber argument of ddi_add_intr().

		       Only devices that generate interrupts have an interrupts property.

       reg	       An  arbitrary-length array where each element of the array consists of a 3-tuple of integers.  Each array element describes
		       a contiguous memory address range associated with the device on the bus.

		       The first integer of the tuple specifies the memory type, 0 specifies a memory range and 1 specifies an I/O range. The sec-
		       ond  integer  specifies	the  base  address  of the memory range. The third integer of each 3-tuple specifies  the size, in
		       bytes, of the mappable region.

		       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().

		       All   sysbus  devices  have reg properties.  The first tuple of this property  is used to construct the address part of the
		       device name under  /devices. In the case of Plug and Play ISA devices, the first tuple is a special  tuple  that  does  not
		       denote  a  memory  range, but is used by the system only to create the address part of the device name.	This special tuple
		       can be recognized by determining if the top bit of the first integer is set to a one.

		       The order of the tuples in the reg property is determined by the boot system probe code and depends on the  characteristics
		       of  each particular device.  However, the reg property maintains the same order of entries from system boot to system boot.
		       The recommended way to determine the reg property for  a  particular  device  is  to  use  the  prtconf(1M)  command  after
		       installing  the particular device.  The output of the prtconf command can be examined to determine the reg property for any
		       installed device.

		       You can use the ddi_get* and ddi_put* family of functions to access register space from a high-level interrupt context.

       dma-channels    A list of integers that specifies the DMA channels used by this device. Only devices that use DMA channels have a dma-chan-
		       nels property.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Architecture		     |x86			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       prtconf(1M), driver.conf(4), scsi(4), attributes(5), ddi_add_intr(9F), ddi_intr_hilevel(9F), ddi_map_regs(9F), ddi_prop_op(9F)

       Writing Device Drivers

SunOS 5.10							    18 Nov 2004 							 sysbus(4)