Mapping An SBus Device

Here is a general method for mapping an SBus device from the ok prompt, without the necessity of knowing system-dependent device addresses. This method does not depend on the presence of a valid FCode PROM on the SBus device. The method will work on any OpenBoot system version 2.0 or higher.

ok " /sbus"  select-dev
ok (offset) (slot#) (size) map-in ( virt )
ok

For example, to inspect the FCode PROM for a device in slot #3 of a system, enter:

ok " /sbus"  select-dev
ok 0 3 1000 map-in  .s
ffed3000
ok dup 20 dump
(Dump of first 20 bytes of FCode PROM)
ok

Here are some variations to the method:

1. On some systems, the pathname for the system SBus may vary. For example, " /iommu/sbus" (for Sun4m) or " /io-unit/sbi" (for Sun4d). The show-devs command from the ok prompt (which lists all system devices) is one way to determine the correct path.

2. Direct placement of (offset size) on the stack may or may not work in the most general cases on future systems. If you encounter problems, try the following, more general approach:

   ---

   ok " /sbus" select-dev
   ok " 3,0: decode-unit  ( offset space )
   ok 1000 map-in         ( virt )
   ok

   ---