From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Joel Stanley <joel@jms.id.au>
Cc: Jiri Slaby <jslaby@suse.com>, Mark Rutland <mark.rutland@arm.com>,
Rob Herring <robh+dt@kernel.org>, Jeremy Kerr <jk@ozlabs.org>,
linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
openbmc@lists.ozlabs.org, devicetree@vger.kernel.org
Subject: Re: [PATCH 2/2] drivers/serial: Add driver for Aspeed virtual UART
Date: Sat, 01 Apr 2017 08:29:40 +1100 [thread overview]
Message-ID: <1490995780.3177.245.camel@kernel.crashing.org> (raw)
In-Reply-To: <20170331133120.GA26078@kroah.com>
On Fri, 2017-03-31 at 15:31 +0200, Greg Kroah-Hartman wrote:
> DEVICE_ATTR_RW()?
>
> And why random sysfs files for a uart? Where have you documented
> these?
We should stick a file somewhere in Documentation I suppose or
at least put that in a comment blob at the head of the file.
FYI:
The VUART is basically two UART 'front ends' connected by their FIFO
(no actual serial line in between). One is on the BMC side (management
controller) and one is on the host CPU side.
It allows the BMC to provide to the host a "UART" that pipes into
the BMC itself and can then be turned by the BMC into a network console
of some sort for example.
This driver is for the BMC side. The sysfs files allow the BMC
userspace which owns the system configuration policy, to specify
at what IO port and interrupt number the host side will appear
to the host on the Host <-> BMC LPC bus. It could be different on a
different system (though most of them use 3f8/4).
Cheers,
Ben.
next prev parent reply other threads:[~2017-03-31 21:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-28 5:44 [PATCH 0/2] drivers: serial: Aspeed VUART driver Joel Stanley
2017-03-28 5:44 ` [PATCH 1/2] serial: 8250: Add flag so drivers can avoid THRE probe Joel Stanley
2017-03-28 5:44 ` [PATCH 2/2] drivers/serial: Add driver for Aspeed virtual UART Joel Stanley
[not found] ` <20170328054458.29341-3-joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org>
2017-03-31 13:31 ` Greg Kroah-Hartman
2017-03-31 21:29 ` Benjamin Herrenschmidt [this message]
2017-04-02 13:07 ` Andy Shevchenko
[not found] ` <CAHp75VfmbHrPFXO3UFmSciCnVuoB+5vFxy7iOnwVS5YBSPO3+Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-04-02 21:09 ` Benjamin Herrenschmidt
2017-04-03 7:11 ` Joel Stanley
2017-04-03 14:25 ` Rob Herring
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