Documentation: kernel-parameters: Add DEVNAME:0.0 format for serial ports

Document the console option for DEVNAME:0.0 style addressing for serial
ports.

Suggested-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20240327110021.59793-8-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tony Lindgren 2024-03-27 12:59:41 +02:00 committed by Greg Kroah-Hartman
parent a8b04cfe7d
commit 5c3a766e9f

View file

@ -785,6 +785,25 @@
Documentation/networking/netconsole.rst for an
alternative.
<DEVNAME>:<n>.<n>[,options]
Use the specified serial port on the serial core bus.
The addressing uses DEVNAME of the physical serial port
device, followed by the serial core controller instance,
and the serial port instance. The options are the same
as documented for the ttyS addressing above.
The mapping of the serial ports to the tty instances
can be viewed with:
$ ls -d /sys/bus/serial-base/devices/*:*.*/tty/*
/sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0
In the above example, the console can be addressed with
console=00:04:0.0. Note that a console addressed this
way will only get added when the related device driver
is ready. The use of an earlycon parameter in addition to
the console may be desired for console output early on.
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
uart[8250],mmio16,<addr>[,options]