From: Arnd Bergmann <arnd@arndb.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>,
gregkh@suse.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] tty: serial: Fix build on architecture that does not have ioport
Date: Fri, 11 Mar 2011 15:16:18 +0100 [thread overview]
Message-ID: <201103111516.19155.arnd@arndb.de> (raw)
In-Reply-To: <20110311135414.2725b861@lxorguk.ukuu.org.uk>
On Friday 11 March 2011, Alan Cox wrote:
> > Some CPU's do not have ioport. Therefore, these do not have inX/outX.
>
> The results of doing that are usually horrible and add a lot of
> configuration and ifdefs.
I guess a different implementation of this patch could convert the
driver to use ioport_map and ioread/iowrite to get rid of the
#ifdef. This might even make the driver simpler because it
does not have to special-case mmio vs. pio accesses.
Note that the 8250 driver is the basically the only driver that
uses inb/outb that can be built without setting CONFIG_ISA
or CONFIG_PCI.
> You will then get a backtrace if the methods are called rather than
> having to hack all the drivers. In addition if your platform ever has a
> PCI bridge attached to it you will now be able to replace those methods
> and provide PCI I/O space access, as you will need for many PCI devices.
That does not seem easier than writing new I/O space functions and
removing CONFIG_NO_IOPORT.
Arnd
next prev parent reply other threads:[~2011-03-11 14:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-11 12:58 [PATCH 1/3] tty: serial: Use hub6_serial_X when CONFIG_SERIAL_8250_HUB6 is defined Nobuhiro Iwamatsu
2011-03-11 12:58 ` [PATCH 2/3] tty: serial: Fix build on architecture that does not have ioport Nobuhiro Iwamatsu
2011-03-11 13:54 ` Alan Cox
2011-03-11 14:16 ` Arnd Bergmann [this message]
2011-03-11 12:58 ` [PATCH 3/3] tty: serial: Check UPF_FOURPORT, when CONFIG_SERIAL_8250_FOURPORT is defined Nobuhiro Iwamatsu
2011-03-11 13:55 ` Alan Cox
2011-03-11 13:50 ` [PATCH 1/3] tty: serial: Use hub6_serial_X when CONFIG_SERIAL_8250_HUB6 " Alan Cox
2011-03-11 13:56 ` Arnd Bergmann
2011-03-11 14:30 ` Alan Cox
2011-03-11 14:54 ` Arnd Bergmann
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