From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 3 Jul 2001 04:13:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 3 Jul 2001 04:12:59 -0400 Received: from t2.redhat.com ([199.183.24.243]:62454 "HELO executor.cambridge.redhat.com") by vger.kernel.org with SMTP id ; Tue, 3 Jul 2001 04:12:46 -0400 To: Russell King Cc: Alan Cox , David Woodhouse , David Howells , Jes Sorensen , arjanv@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [RFC] I/O Access Abstractions In-Reply-To: Your message of "Mon, 02 Jul 2001 19:11:29 BST." <20010702191129.A29246@flint.arm.linux.org.uk> Date: Tue, 03 Jul 2001 09:12:44 +0100 Message-ID: <3953.994147964@warthog.cambridge.redhat.com> From: David Howells Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Russell King wrote: > They _ARE_ different, because people connect these chips in many different > ways. For example: Also hence the mess in serial.c. On the board I'm currently dealing with, the PC16550 chip is connected to the memory space with registers at 4-byte intervals because the chip is an 8-bit chip connected to a 32-bit data bus (and so ignored addr lines A0 and A1). Whereas on the PC, various serial register sets appear generally in I/O port space at 1-byte intervals from some base address. This could be greatly simplified with the method I'm proposing. The resource access function could make the address space for that device to be eight consecutive registers regardless of the reality. David