From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8BA50C48BDF for ; Thu, 10 Jun 2021 18:37:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7599B613DF for ; Thu, 10 Jun 2021 18:37:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230286AbhFJSjw (ORCPT ); Thu, 10 Jun 2021 14:39:52 -0400 Received: from angie.orcam.me.uk ([78.133.224.34]:41586 "EHLO angie.orcam.me.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230216AbhFJSjw (ORCPT ); Thu, 10 Jun 2021 14:39:52 -0400 Received: by angie.orcam.me.uk (Postfix, from userid 500) id ECBCA92009E; Thu, 10 Jun 2021 20:37:53 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id E709D92009D; Thu, 10 Jun 2021 20:37:53 +0200 (CEST) Date: Thu, 10 Jun 2021 20:37:53 +0200 (CEST) From: "Maciej W. Rozycki" To: Greg Kroah-Hartman , Jiri Slaby , Thomas Bogendoerfer cc: linux-serial@vger.kernel.org, linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 0/2] serial, Malta: Fixes to make the CBUS UART work big-endian Message-ID: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Earlier this year I noticed the CBUS UART, a discrete TI16C550C part wired directly to the system controller's device bus and supposed to come up as ttyS2 in addition to ttyS0 and ttyS1 ports from a Super I/O device behind the PCI southbridge, is not recognised with my MIPS Malta board booting big-endian. I used to use it just fine, many many years ago, although in the board's little-endian configuration only, and then with a local patch to get it supported with Linux 2.4.x, which I didn't get to submitting however due to the turn of events back then. Support was then added by someone else with 2.6.23. I got to the bottom of the problem now and as it turns out we have two long-standing bugs causing it, one in generic 8250 code and another in Malta platform code, and this has never worked in the big-endian mode. Evidently, this has never been verified, and I guess this is because back in the MIPS UK days we usually ran the boards in the little-endian mode. This pair of patches addresses these bugs individually. See the respective change descriptions for details. Please apply. Maciej