Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965834AbWKEERT (ORCPT ); Sat, 4 Nov 2006 23:17:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965835AbWKEERT (ORCPT ); Sat, 4 Nov 2006 23:17:19 -0500 Received: from smtp.osdl.org ([65.172.181.4]:2204 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S965834AbWKEERS (ORCPT ); Sat, 4 Nov 2006 23:17:18 -0500 Date: Sat, 4 Nov 2006 20:16:59 -0800 (PST) From: Linus Torvalds To: Benjamin Herrenschmidt cc: Russell King , Linux Kernel list , Jeff Garzik , Andrew Morton , "David S. Miller" , Paul Mackerras Subject: Re: lib/iomap.c mmio_{in,out}s* vs. __raw_* accessors In-Reply-To: <1162699255.28571.150.camel@localhost.localdomain> Message-ID: References: <1162626761.28571.14.camel@localhost.localdomain> <20061104140559.GC19760@flint.arm.linux.org.uk> <1162678639.28571.63.camel@localhost.localdomain> <1162689005.28571.118.camel@localhost.localdomain> <1162697533.28571.131.camel@localhost.localdomain> <1162699255.28571.150.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1280 Lines: 35 On Sun, 5 Nov 2006, Benjamin Herrenschmidt wrote: > > > > Just rip the _be versions out, methinks. > > At least one user: > > ./drivers/scsi/53c700.h: __u32 value = bEBus ? ioread32be(hostdata->base + reg) : > ./drivers/scsi/53c700.h: bEBus ? iowrite32be(value, hostdata->base + reg): > > Should I make it use explicit swab32 instead ? Well, I actually really dislike your version with the explicit swab. The _only_ reason to use "ioread32be()" would be because the machine is actually natively BE, and you want to avoid swab. That's kind of the point of using "be32_to_cpu(__raw_readl(addr)))" like we do now - it will do the byte swap only if it's necessary. In contrast, your "swab(readl())" does _two_ byteswaps - once to turn it into LE, then to turn it back into BE. So if we can't just rip it out, then we sure as hell shouldn't replace it with something that is obviously worse either. In other words - I don't see the reasoning here again. You seem to want to make the code just worse. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/