From owner-freebsd-arm@FreeBSD.ORG  Thu Jan 17 03:26:38 2013
Return-Path: <owner-freebsd-arm@FreeBSD.ORG>
Delivered-To: arm@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by hub.freebsd.org (Postfix) with ESMTP id 9BA07A8D
 for <arm@FreeBSD.org>; Thu, 17 Jan 2013 03:26:38 +0000 (UTC)
 (envelope-from ian@FreeBSD.org)
Received: from duck.symmetricom.us (duck.symmetricom.us [206.168.13.214])
 by mx1.freebsd.org (Postfix) with ESMTP id 0A3C76F1
 for <arm@FreeBSD.org>; Thu, 17 Jan 2013 03:26:34 +0000 (UTC)
Received: from damnhippie.dyndns.org (daffy.symmetricom.us [206.168.13.218])
 by duck.symmetricom.us (8.14.5/8.14.5) with ESMTP id r0H3QYB2083123
 for <arm@FreeBSD.org>; Wed, 16 Jan 2013 20:26:34 -0700 (MST)
 (envelope-from ian@FreeBSD.org)
Received: from [172.22.42.240] (revolution.hippie.lan [172.22.42.240])
 by damnhippie.dyndns.org (8.14.3/8.14.3) with ESMTP id r0H3QWkd005620;
 Wed, 16 Jan 2013 20:26:32 -0700 (MST) (envelope-from ian@FreeBSD.org)
Subject: Re: bus_space_(write|read)_X cleanup
From: Ian Lepore <ian@FreeBSD.org>
To: Oleksandr Tymoshenko <gonzo@bluezbox.com>
In-Reply-To: <50F70325.5070507@bluezbox.com>
References: <50F70325.5070507@bluezbox.com>
Content-Type: text/plain; charset="us-ascii"
Date: Wed, 16 Jan 2013 20:26:32 -0700
Message-ID: <1358393192.32417.186.camel@revolution.hippie.lan>
Mime-Version: 1.0
X-Mailer: Evolution 2.32.1 FreeBSD GNOME Team Port 
Content-Transfer-Encoding: 7bit
Cc: arm@FreeBSD.org
X-BeenThere: freebsd-arm@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Porting FreeBSD to the StrongARM Processor <freebsd-arm.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-arm>,
 <mailto:freebsd-arm-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arm>
List-Post: <mailto:freebsd-arm@freebsd.org>
List-Help: <mailto:freebsd-arm-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arm>,
 <mailto:freebsd-arm-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 17 Jan 2013 03:26:38 -0000

On Wed, 2013-01-16 at 11:44 -0800, Oleksandr Tymoshenko wrote:
> Hello,
> 
> One of the practices in ARM codebase that caught my eye recently
> was using bus_space_write_4 (and read) where it's not strictly required.
> 
> The way it usually goes: memory resource is allocated in driver's attach
> method then busspace tag/handle obtained by calling rman_get_bustag
> and rman_get_bushandle, stored in softc and used as a parameters  of
> bus_space calls. No other operations on handle/tag are performed.
> 
> There are bus_read/bus_write wrappers that provide cleaner API
> and reduce code complexity. I believe it might be worth going through
> the code and fixing cases of excessive use of bus_space_  functions.
> 
> Unless I missed something.

I don't think you missed anything, and I totally agree with this.

Something I tried for a while was to extend the shorthand to the next
logical level.  We have 

  bus_space_whatever(sc->restag, sc->reshandle, ...)

then 

  bus_whatever(sc->resource, ...)

so next for me is

  device_whatever(sc, ...)

But I fell back out of the habit pretty quickly.  What I still like best
of all is the RD4() and WR4() macros that Warner used in the at91 code.
They are the same idea as my device_whatever() but with uglier names
(that I still like better despite all the ugly).

-- Ian