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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3E1CEB64D9 for ; Wed, 12 Jul 2023 08:20:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232067AbjGLIUr convert rfc822-to-8bit (ORCPT ); Wed, 12 Jul 2023 04:20:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232508AbjGLIUQ (ORCPT ); Wed, 12 Jul 2023 04:20:16 -0400 Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A83C12706; Wed, 12 Jul 2023 01:16:55 -0700 (PDT) Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.95) with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1qJV0i-003CBT-OC; Wed, 12 Jul 2023 10:15:44 +0200 Received: from p57bd9f0d.dip0.t-ipconnect.de ([87.189.159.13] helo=[192.168.178.81]) by inpost2.zedat.fu-berlin.de (Exim 4.95) with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1qJV0i-001l2s-F8; Wed, 12 Jul 2023 10:15:44 +0200 Message-ID: Subject: Re: [PATCH] sh: Avoid using IRQ0 on SH3 and SH4 From: John Paul Adrian Glaubitz To: David Laight , Guenter Roeck , Sergey Shtylyov , Geert Uytterhoeven Cc: Yoshinori Sato , Rich Felker , "linux-sh@vger.kernel.org" , "linux-kernel@vger.kernel.org" Date: Wed, 12 Jul 2023 10:15:43 +0200 In-Reply-To: References: <7b2c0d812280afaefee0c70a9aea00a0fcf84e3a.camel@physik.fu-berlin.de> <1178f8d0-be70-c088-ee6a-8b421b290624@roeck-us.net> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.48.4 MIME-Version: 1.0 X-Original-Sender: glaubitz@physik.fu-berlin.de X-Originating-IP: 87.189.159.13 X-ZEDAT-Hint: PO Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi David! On Wed, 2023-07-12 at 08:12 +0000, David Laight wrote: > From: John Paul Adrian Glaubitz > > Sent: 09 July 2023 00:13 > .... > > Looking at arch/sh/boards/mach-r2d/irq.c, there is some IRQ translation going > > on and maybe that's the part where we need to correct the offset by 16? > > Would it be less problematic to use (say) 16 for IRQ_0 > leaving IRQ_1+ as 1+ ? That would make things more complicated as IRQ0 would have to be handled individually. > At least that would only cause issues for code that needed > to use IRQ_0. What issues are you seeing or expecting? > (It has to be said that making IRQ 0 invalid seemed wrong > to me. x86 (IBM PC) gets away with it because IRQ 0 is > always assigned to platform specific hardware.) It's invalid for driver code, not for architecture code. Adrian -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer `. `' Physicist `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913