Date: Sun, 26 Apr 2026 11:04:24 +0000 From: bugzilla-noreply@freebsd.org To: doc@FreeBSD.org Subject: [Bug 294793] ofw(4) manpage Message-ID: <bug-294793-9-hUgsfzUsIl@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-294793-9@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=294793 B1nc0d3x <b1nc0d3x@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Attachment #270120|0 |1 is patch| | --- Comment #1 from B1nc0d3x <b1nc0d3x@gmail.com> --- Comment on attachment 270120 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=270120 Manpage for ofw(4) >.\"- >.\" Copyright (c) 2025 Kyle Crenshaw <b1nc0d3x> >.\" All rights reserved. >.\" >.\" Redistribution and use in source and binary forms, with or without >.\" modification, are permitted provided that the following conditions >.\" are met: >.\" 1. Redistributions of source code must retain the above copyright >.\" notice, this list of conditions and the following disclaimer. >.\" 2. Redistributions in binary form must reproduce the above copyright >.\" notice, this list of conditions and the following disclaimer in the >.\" documentation and/or other materials provided with the distribution. >.\" >.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR >.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES >.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. >.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, >.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT >.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, >.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY >.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT >.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF >.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. >.\" >.Dd April 25, 2025 >.Dt OFW 4 >.Os >.Sh NAME >.Nm ofw >.Nd Open Firmware device tree bus >.Sh SYNOPSIS >.Cd "options FDT" >.Sh DESCRIPTION >The >.Nm >driver, also known as >.Nm ofwbus , >is a pseudo-bus that enumerates top-level devices from the >Open Firmware device tree and attaches them as children in the >.Xr newbus 9 >device hierarchy. >There is at most one >.Nm ofwbus >instance in the system; it attaches directly as a child of the root nexus. >.Pp >Open Firmware >.Pq OF >is a platform-independent firmware interface described by >IEEE Std 1275-1994. >It provides a hierarchical device tree that describes the hardware >resources present on a system. >Nodes in the tree represent devices and buses; each node carries a set of >named properties that encode addresses, interrupt routing, and other >configuration data. >.Pp >The >.Nm >driver iterates over the direct children of the Open Firmware root node >and instantiates a >.Xr newbus 9 >device for each one. >Child drivers use the kernel OFW interface >.Pq see Xr OF_getprop 9 , Xr OF_child 9 >to query device tree properties and configure their hardware. >.Pp >The following OFW backend implementations are supported: >.Bl -tag -width "ofw_32bit" >.It Cm ofw_std >Standard IEEE 1275 client-interface, used on platforms where >Open Firmware is directly callable from supervisor mode >.Pq e.g., 32-bit PowerPC . >.It Cm ofw_real >Real-mode Open Firmware interface, used on platforms where the firmware >must be called in real (physical) addressing mode >.Pq e.g., some 64-bit PowerPC implementations . >.It Cm ofw_32bit >32-bit compatibility Open Firmware interface for 64-bit platforms >that provide a 32-bit firmware call ABI. >.It Cm ofw_fdt >Flattened Device Tree >.Pq FDT >backend. >This is selected when the >.Cd "options FDT" >kernel option is set. >Instead of a live firmware call interface, >.Cm ofw_fdt >interprets a static binary device tree blob >.Pq DTB >passed by the bootloader. >This backend is used on ARM, ARM64, and RISC-V platforms. >.El >.Pp >The backend is selected early during boot, before newbus initialisation, >by calling >.Fn OF_install >with the appropriate name string, then >.Fn OF_init >with the firmware entry point or device tree blob address as a cookie. >.Pp >A userspace interface to the device tree is provided by the >.Pa /dev/openfirm >character device; see >.Xr openfirm 4 >for a description of the >.Xr ioctl 2 >operations it supports. >The >.Xr ofwdump 8 >utility may be used to examine the device tree from the command line. >.Sh FILES >.Bl -tag -width ".Pa /dev/openfirm" -compact >.It Pa /dev/openfirm >Userspace interface to the Open Firmware device tree >.El >.Sh SEE ALSO >.Xr fdt 4 , >.Xr openfirm 4 , >.Xr simplebus 4 , >.Xr ofwdump 8 , >.Xr OF_child 9 , >.Xr OF_getprop 9 , >.Xr OF_node_from_xref 9 >.Sh STANDARDS >.Rs >.%Q "IEEE Standards Organization" >.%B "IEEE Std 1275-1994: IEEE Standard for Boot (Initialization Configuration) Firmware: Core Requirements and Practices" >.%O "ISBN 1-55937-426-8" >.Re >.Sh HISTORY >Open Firmware support first appeared in >.Fx 5.0 . >The >.Cm ofw_fdt >backend was added in >.Fx 9.0 . >.Sh AUTHORS >.An -nosplit >The >.Nm >driver was written by >.An Benno Rice Aq Mt benno@FreeBSD.org . >The >.Cm ofw_fdt >backend was written by >.An Rafal Jaworowski >under sponsorship from the >.Fx >Foundation. >This manual page was written by >.An Kyle Crenshaw <b1nc0d3x> Aq Mt b1nc0d3x@gmail.com . -- You are receiving this mail because: You are on the CC list for the bug.home | help
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