[Bug 294793] ofw(4) manpage

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=294793

            Bug ID: 294793
           Summary: ofw(4) manpage
           Product: Documentation
           Version: Latest
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Many People
          Priority: ---
         Component: Manual Pages
          Assignee: [email protected]
          Reporter: [email protected]
                CC: [email protected]
 Attachment #270120 text/plain
         mime type:

Created attachment 270120
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=270120&action=edit
Manpage for ofw(4)

Summary: ofw(4) manual page
==========================

What ofw(4) documents
----------------------
ofw(4) documents the ofwbus driver — the Open Firmware pseudo-bus that
sits directly under nexus(4) and enumerates top-level devices from the
Open Firmware device tree, attaching them as children in the newbus(9)
hierarchy.

The page covers:

  - What Open Firmware is and how the device tree is structured
    (IEEE Std 1275-1994)
  - How ofwbus iterates the OF root node and instantiates newbus devices
  - The four supported OFW backend implementations:
      ofw_std    Standard direct-call interface (e.g. 32-bit PowerPC)
      ofw_real   Real-mode interface (e.g. 64-bit PowerPC)
      ofw_32bit  32-bit ABI compatibility interface
      ofw_fdt    Flattened Device Tree backend (ARM, ARM64, RISC-V)
  - How the backend is selected at boot via OF_install()/OF_init()
  - The /dev/openfirm userspace interface (cross-referenced to openfirm(4))
  - Pointers to ofwdump(8) for command-line device tree inspection

Why it was missing
-------------------
The FreeBSD src tree already has closely related pages:

  openfirm(4)   Documents the /dev/openfirm character device and its
                ioctl interface — the userspace side of OFW.
  simplebus(4)  Documents the ePAPR simple-bus driver that sits under
                ofwbus on FDT-based systems.
  fdt(4)        Documents the Flattened Device Tree subsystem.
  ofw_console(4) Documents the Open Firmware fallback console (powerpc).

However, none of these explain the ofwbus driver itself — the component
that actually bridges Open Firmware to newbus and makes device
enumeration possible on PowerPC, ARM, ARM64, and RISC-V.  Both
ofwdump(8) and simplebus(4) cross-reference openfirm(4) for background,
but there was no page describing the bus driver that underpins the entire
OFW subsystem.  ofw(4) fills that gap.

-- 
You are receiving this mail because:
You are on the CC list for the bug.