From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: [PATCH 3/3] 8250: add workaround for MPC8[356]xx UART break IRQ storm Date: Fri, 2 Dec 2011 11:27:12 -0600 Message-ID: <4ED90A70.8000902@freescale.com> References: <1322783258-20443-1-git-send-email-paul.gortmaker@windriver.com> <1322783258-20443-4-git-send-email-paul.gortmaker@windriver.com> <4ED812E4.60905@freescale.com> <4ED81632.3030809@windriver.com> <176AE2A1-6AA2-4F14-942F-8ED77AB1DBEC@kernel.crashing.org> <20111202113059.15d73840@lxorguk.ukuu.org.uk> <4ED8FE14.7020007@windriver.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from va3ehsobe010.messaging.microsoft.com ([216.32.180.30]:32682 "EHLO VA3EHSOBE010.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757157Ab1LBR1U (ORCPT ); Fri, 2 Dec 2011 12:27:20 -0500 In-Reply-To: <4ED8FE14.7020007@windriver.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Paul Gortmaker Cc: Alan Cox , Kumar Gala , gregkh@suse.de, alan@linux.intel.com, linux-serial@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org On 12/02/2011 10:34 AM, Paul Gortmaker wrote: > On 11-12-02 06:30 AM, Alan Cox wrote: >>>> OK, I'll simply change the above to CONFIG_PPC then. >>> >>> It does, the bug is in the uart IP which I don't think we ever plan on fixing, so 32 or 64-bit parts will have it for ever and ever ;) >> >> It should be runtime selected, there should be no ifdefs here. > > The ifdef wasn't strictly required; it just made it so gcc would > toss the errata code out of the irq handler for !PPC. Anyway it > will be a moot point if I can somehow hide all the mess by snooping > serial_inp() traffic and deploying the errata fix from there.... Eww. If it's not to be allowed in the main 8250 code (even for ppc builds only), a custom handle_port sounds like a saner option. -Scott From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from VA3EHSOBE010.bigfish.com (va3ehsobe010.messaging.microsoft.com [216.32.180.30]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "Microsoft Secure Server Authority" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id EE5E5B6F75 for ; Sat, 3 Dec 2011 04:27:25 +1100 (EST) Message-ID: <4ED90A70.8000902@freescale.com> Date: Fri, 2 Dec 2011 11:27:12 -0600 From: Scott Wood MIME-Version: 1.0 To: Paul Gortmaker Subject: Re: [PATCH 3/3] 8250: add workaround for MPC8[356]xx UART break IRQ storm References: <1322783258-20443-1-git-send-email-paul.gortmaker@windriver.com> <1322783258-20443-4-git-send-email-paul.gortmaker@windriver.com> <4ED812E4.60905@freescale.com> <4ED81632.3030809@windriver.com> <176AE2A1-6AA2-4F14-942F-8ED77AB1DBEC@kernel.crashing.org> <20111202113059.15d73840@lxorguk.ukuu.org.uk> <4ED8FE14.7020007@windriver.com> In-Reply-To: <4ED8FE14.7020007@windriver.com> Content-Type: text/plain; charset="ISO-8859-1" Cc: gregkh@suse.de, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Alan Cox , alan@linux.intel.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 12/02/2011 10:34 AM, Paul Gortmaker wrote: > On 11-12-02 06:30 AM, Alan Cox wrote: >>>> OK, I'll simply change the above to CONFIG_PPC then. >>> >>> It does, the bug is in the uart IP which I don't think we ever plan on fixing, so 32 or 64-bit parts will have it for ever and ever ;) >> >> It should be runtime selected, there should be no ifdefs here. > > The ifdef wasn't strictly required; it just made it so gcc would > toss the errata code out of the irq handler for !PPC. Anyway it > will be a moot point if I can somehow hide all the mess by snooping > serial_inp() traffic and deploying the errata fix from there.... Eww. If it's not to be allowed in the main 8250 code (even for ppc builds only), a custom handle_port sounds like a saner option. -Scott From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757191Ab1LBR1W (ORCPT ); Fri, 2 Dec 2011 12:27:22 -0500 Received: from va3ehsobe010.messaging.microsoft.com ([216.32.180.30]:32682 "EHLO VA3EHSOBE010.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757157Ab1LBR1U (ORCPT ); Fri, 2 Dec 2011 12:27:20 -0500 X-SpamScore: -18 X-BigFish: VS-18(zzbb2dK9371K936eK1432N98dKzz1202hzzz2dh2a8h668h839h) X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI Message-ID: <4ED90A70.8000902@freescale.com> Date: Fri, 2 Dec 2011 11:27:12 -0600 From: Scott Wood User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:6.0.2) Gecko/20110906 Thunderbird/6.0.2 MIME-Version: 1.0 To: Paul Gortmaker CC: Alan Cox , Kumar Gala , , , , , Subject: Re: [PATCH 3/3] 8250: add workaround for MPC8[356]xx UART break IRQ storm References: <1322783258-20443-1-git-send-email-paul.gortmaker@windriver.com> <1322783258-20443-4-git-send-email-paul.gortmaker@windriver.com> <4ED812E4.60905@freescale.com> <4ED81632.3030809@windriver.com> <176AE2A1-6AA2-4F14-942F-8ED77AB1DBEC@kernel.crashing.org> <20111202113059.15d73840@lxorguk.ukuu.org.uk> <4ED8FE14.7020007@windriver.com> In-Reply-To: <4ED8FE14.7020007@windriver.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/02/2011 10:34 AM, Paul Gortmaker wrote: > On 11-12-02 06:30 AM, Alan Cox wrote: >>>> OK, I'll simply change the above to CONFIG_PPC then. >>> >>> It does, the bug is in the uart IP which I don't think we ever plan on fixing, so 32 or 64-bit parts will have it for ever and ever ;) >> >> It should be runtime selected, there should be no ifdefs here. > > The ifdef wasn't strictly required; it just made it so gcc would > toss the errata code out of the irq handler for !PPC. Anyway it > will be a moot point if I can somehow hide all the mess by snooping > serial_inp() traffic and deploying the errata fix from there.... Eww. If it's not to be allowed in the main 8250 code (even for ppc builds only), a custom handle_port sounds like a saner option. -Scott