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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 256DAC433F5 for ; Tue, 5 Oct 2021 22:25:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08093610E5 for ; Tue, 5 Oct 2021 22:25:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236750AbhJEW10 (ORCPT ); Tue, 5 Oct 2021 18:27:26 -0400 Received: from foss.arm.com ([217.140.110.172]:34334 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236697AbhJEW10 (ORCPT ); Tue, 5 Oct 2021 18:27:26 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D02B56D; Tue, 5 Oct 2021 15:25:34 -0700 (PDT) Received: from [192.168.122.166] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D5B2B3F66F; Tue, 5 Oct 2021 15:25:33 -0700 (PDT) Subject: Re: [PATCH v3 2/4] PCI: brcmstb: Add ACPI config space quirk To: =?UTF-8?Q?Pali_Roh=c3=a1r?= Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, lorenzo.pieralisi@arm.com, nsaenz@kernel.org, bhelgaas@google.com, rjw@rjwysocki.net, lenb@kernel.org, robh@kernel.org, kw@linux.com, f.fainelli@gmail.com, bcm-kernel-feedback-list@broadcom.com, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20211005153209.GA1083986@bhelgaas> <20211005194301.enb5jddzdgczcolx@pali> From: Jeremy Linton Message-ID: <694bb355-3b5e-9801-3772-ff784b49a603@arm.com> Date: Tue, 5 Oct 2021 17:25:33 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20211005194301.enb5jddzdgczcolx@pali> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi, On 10/5/21 2:43 PM, Pali Rohár wrote: > Hello! > > On Tuesday 05 October 2021 10:57:18 Jeremy Linton wrote: >> Hi, >> >> On 10/5/21 10:32 AM, Bjorn Helgaas wrote: >>> On Thu, Aug 26, 2021 at 02:15:55AM -0500, Jeremy Linton wrote: >>>> Additionally, some basic bus/device filtering exist to avoid sending >>>> config transactions to invalid devices on the RP's primary or >>>> secondary bus. A basic link check is also made to assure that >>>> something is operational on the secondary side before probing the >>>> remainder of the config space. If either of these constraints are >>>> violated and a config operation is lost in the ether because an EP >>>> doesn't respond an unrecoverable SERROR is raised. >>> >>> It's not "lost"; I assume the root port raises an error because it >>> can't send a transaction over a link that is down. >> >> The problem is AFAIK because the root port doesn't do that. > > Interesting! Does it mean that PCIe Root Complex / Host Bridge (which I > guess contains also logic for Root Port) does not signal transaction > failure for config requests? Or it is just your opinion? Because I'm > dealing with similar issues and I'm trying to find a way how to detect > if some PCIe IP signal transaction error via AXI SLVERR response OR it > just does not send any response back. So if you know some way how to > check which one it is, I would like to know it too. This is my _opinion_ based on what I've heard of some other IP integration issues, and what i've seen poking at this one from the perspective of a SW guy rather than a HW guy. So, basically worthless. But, you should consider that most of these cores/interconnects aren't aware of PCIe completion semantics so its the root ports responsibility to say, gracefully translate a non-posted write that doesn't have a completion for the interconnects its attached to, rather than tripping something generic like a SLVERR. Anyway, for this I would poke around the pile of exception registers, with your specific processors manual handy because a lot of them are implementation defined. >>> >>> Is "SERROR" an ARM64 thing? My guess is the root port would raise an >>> Unsupported Request error or similar, and the root complex turns that >>> into a system-specific SERROR? > > Yes, SError is arm64 specific. It is asynchronous CPU interrupt and > syndrome code then contains what happened. > >> AFAIK, what is happening here the CPU core has an outstanding R/W request >> for which it never receives a response from the root port. So basically its >> an interconnect protocol violation that the CPU is complaining about rather >> than something PCIe specific. > > Could you describe (ideally in commit message) which SError is > triggered? Normally if kernel receive SError interrupt it also puts into > dmesg or oops message also syndrome code which describe what kind of > error / event occurred. It could help also to other understand what is > happening there. > 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7EFADC433F5 for ; Tue, 5 Oct 2021 22:27:40 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4544561100 for ; Tue, 5 Oct 2021 22:27:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4544561100 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:Cc:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=mShcaiUmf1Fxx3MSUvol3cOXJEKkQJKFSkPJZ1qQvB0=; b=aPypMPPt58f+MjxUg6QFMCbmmF KOgi97wEuf3NxXKTvVTCNmMlsPUZrRLVbDrWN+THs6QMk2UhVV+xe6piSBeIvIU1lOXtnAwxjq4ta ufXLc1SBj9SfoAaTsb/j0lSJNNCbNw5EVxS6DpXwpj3YThRccW6lthvUxfWxZSy2dgse13KFl99tP PAqLYaHpo3XGRFtKWRVp3ZvR30p2eDbI8DP0SYrsttikcxZc6X5MysrSHIE4zejPdsxbYUcvEKVAf Ua/ob9IayjCSbdg/ahwPj5mCfM/Gl/ysvZITiSGBuUIqt/VxNIb/8xyhgWWMF1XEJgc3MPFZizf/U jIDw2haQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mXssb-00C2sS-La; Tue, 05 Oct 2021 22:25:45 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mXssU-00C2rA-ND; Tue, 05 Oct 2021 22:25:40 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D02B56D; Tue, 5 Oct 2021 15:25:34 -0700 (PDT) Received: from [192.168.122.166] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D5B2B3F66F; Tue, 5 Oct 2021 15:25:33 -0700 (PDT) Subject: Re: [PATCH v3 2/4] PCI: brcmstb: Add ACPI config space quirk To: =?UTF-8?Q?Pali_Roh=c3=a1r?= Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, lorenzo.pieralisi@arm.com, nsaenz@kernel.org, bhelgaas@google.com, rjw@rjwysocki.net, lenb@kernel.org, robh@kernel.org, kw@linux.com, f.fainelli@gmail.com, bcm-kernel-feedback-list@broadcom.com, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20211005153209.GA1083986@bhelgaas> <20211005194301.enb5jddzdgczcolx@pali> From: Jeremy Linton Message-ID: <694bb355-3b5e-9801-3772-ff784b49a603@arm.com> Date: Tue, 5 Oct 2021 17:25:33 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20211005194301.enb5jddzdgczcolx@pali> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211005_152538_878563_0CE1B7BE X-CRM114-Status: GOOD ( 27.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org SGksCgpPbiAxMC81LzIxIDI6NDMgUE0sIFBhbGkgUm9ow6FyIHdyb3RlOgo+IEhlbGxvIQo+IAo+ IE9uIFR1ZXNkYXkgMDUgT2N0b2JlciAyMDIxIDEwOjU3OjE4IEplcmVteSBMaW50b24gd3JvdGU6 Cj4+IEhpLAo+Pgo+PiBPbiAxMC81LzIxIDEwOjMyIEFNLCBCam9ybiBIZWxnYWFzIHdyb3RlOgo+ Pj4gT24gVGh1LCBBdWcgMjYsIDIwMjEgYXQgMDI6MTU6NTVBTSAtMDUwMCwgSmVyZW15IExpbnRv biB3cm90ZToKPj4+PiBBZGRpdGlvbmFsbHksIHNvbWUgYmFzaWMgYnVzL2RldmljZSBmaWx0ZXJp bmcgZXhpc3QgdG8gYXZvaWQgc2VuZGluZwo+Pj4+IGNvbmZpZyB0cmFuc2FjdGlvbnMgdG8gaW52 YWxpZCBkZXZpY2VzIG9uIHRoZSBSUCdzIHByaW1hcnkgb3IKPj4+PiBzZWNvbmRhcnkgYnVzLiBB IGJhc2ljIGxpbmsgY2hlY2sgaXMgYWxzbyBtYWRlIHRvIGFzc3VyZSB0aGF0Cj4+Pj4gc29tZXRo aW5nIGlzIG9wZXJhdGlvbmFsIG9uIHRoZSBzZWNvbmRhcnkgc2lkZSBiZWZvcmUgcHJvYmluZyB0 aGUKPj4+PiByZW1haW5kZXIgb2YgdGhlIGNvbmZpZyBzcGFjZS4gSWYgZWl0aGVyIG9mIHRoZXNl IGNvbnN0cmFpbnRzIGFyZQo+Pj4+IHZpb2xhdGVkIGFuZCBhIGNvbmZpZyBvcGVyYXRpb24gaXMg bG9zdCBpbiB0aGUgZXRoZXIgYmVjYXVzZSBhbiBFUAo+Pj4+IGRvZXNuJ3QgcmVzcG9uZCBhbiB1 bnJlY292ZXJhYmxlIFNFUlJPUiBpcyByYWlzZWQuCj4+Pgo+Pj4gSXQncyBub3QgImxvc3QiOyBJ IGFzc3VtZSB0aGUgcm9vdCBwb3J0IHJhaXNlcyBhbiBlcnJvciBiZWNhdXNlIGl0Cj4+PiBjYW4n dCBzZW5kIGEgdHJhbnNhY3Rpb24gb3ZlciBhIGxpbmsgdGhhdCBpcyBkb3duLgo+Pgo+PiBUaGUg cHJvYmxlbSBpcyBBRkFJSyBiZWNhdXNlIHRoZSByb290IHBvcnQgZG9lc24ndCBkbyB0aGF0Lgo+ IAo+IEludGVyZXN0aW5nISBEb2VzIGl0IG1lYW4gdGhhdCBQQ0llIFJvb3QgQ29tcGxleCAvIEhv c3QgQnJpZGdlICh3aGljaCBJCj4gZ3Vlc3MgY29udGFpbnMgYWxzbyBsb2dpYyBmb3IgUm9vdCBQ b3J0KSBkb2VzIG5vdCBzaWduYWwgdHJhbnNhY3Rpb24KPiBmYWlsdXJlIGZvciBjb25maWcgcmVx dWVzdHM/IE9yIGl0IGlzIGp1c3QgeW91ciBvcGluaW9uPyBCZWNhdXNlIEknbQo+IGRlYWxpbmcg d2l0aCBzaW1pbGFyIGlzc3VlcyBhbmQgSSdtIHRyeWluZyB0byBmaW5kIGEgd2F5IGhvdyB0byBk ZXRlY3QKPiBpZiBzb21lIFBDSWUgSVAgc2lnbmFsIHRyYW5zYWN0aW9uIGVycm9yIHZpYSBBWEkg U0xWRVJSIHJlc3BvbnNlIE9SIGl0Cj4ganVzdCBkb2VzIG5vdCBzZW5kIGFueSByZXNwb25zZSBi YWNrLiBTbyBpZiB5b3Uga25vdyBzb21lIHdheSBob3cgdG8KPiBjaGVjayB3aGljaCBvbmUgaXQg aXMsIEkgd291bGQgbGlrZSB0byBrbm93IGl0IHRvby4KClRoaXMgaXMgbXkgX29waW5pb25fIGJh c2VkIG9uIHdoYXQgSSd2ZSBoZWFyZCBvZiBzb21lIG90aGVyIElQIAppbnRlZ3JhdGlvbiBpc3N1 ZXMsIGFuZCB3aGF0IGkndmUgc2VlbiBwb2tpbmcgYXQgdGhpcyBvbmUgZnJvbSB0aGUgCnBlcnNw ZWN0aXZlIG9mIGEgU1cgZ3V5IHJhdGhlciB0aGFuIGEgSFcgZ3V5LiBTbywgYmFzaWNhbGx5IHdv cnRobGVzcy4gCkJ1dCwgeW91IHNob3VsZCBjb25zaWRlciB0aGF0IG1vc3Qgb2YgdGhlc2UgY29y ZXMvaW50ZXJjb25uZWN0cyBhcmVuJ3QgCmF3YXJlIG9mIFBDSWUgY29tcGxldGlvbiBzZW1hbnRp Y3Mgc28gaXRzIHRoZSByb290IHBvcnRzIHJlc3BvbnNpYmlsaXR5IAp0byBzYXksIGdyYWNlZnVs bHkgdHJhbnNsYXRlIGEgbm9uLXBvc3RlZCB3cml0ZSB0aGF0IGRvZXNuJ3QgaGF2ZSBhIApjb21w bGV0aW9uIGZvciB0aGUgaW50ZXJjb25uZWN0cyBpdHMgYXR0YWNoZWQgdG8sIHJhdGhlciB0aGFu IHRyaXBwaW5nIApzb21ldGhpbmcgZ2VuZXJpYyBsaWtlIGEgU0xWRVJSLgoKQW55d2F5LCBmb3Ig dGhpcyBJIHdvdWxkIHBva2UgYXJvdW5kIHRoZSBwaWxlIG9mIGV4Y2VwdGlvbiByZWdpc3RlcnMs IAp3aXRoIHlvdXIgc3BlY2lmaWMgcHJvY2Vzc29ycyBtYW51YWwgaGFuZHkgYmVjYXVzZSBhIGxv dCBvZiB0aGVtIGFyZSAKaW1wbGVtZW50YXRpb24gZGVmaW5lZC4KPj4+Cj4+PiBJcyAiU0VSUk9S IiBhbiBBUk02NCB0aGluZz8gIE15IGd1ZXNzIGlzIHRoZSByb290IHBvcnQgd291bGQgcmFpc2Ug YW4KPj4+IFVuc3VwcG9ydGVkIFJlcXVlc3QgZXJyb3Igb3Igc2ltaWxhciwgYW5kIHRoZSByb290 IGNvbXBsZXggdHVybnMgdGhhdAo+Pj4gaW50byBhIHN5c3RlbS1zcGVjaWZpYyBTRVJST1I/Cj4g Cj4gWWVzLCBTRXJyb3IgaXMgYXJtNjQgc3BlY2lmaWMuIEl0IGlzIGFzeW5jaHJvbm91cyBDUFUg aW50ZXJydXB0IGFuZAo+IHN5bmRyb21lIGNvZGUgdGhlbiBjb250YWlucyB3aGF0IGhhcHBlbmVk Lgo+IAo+PiBBRkFJSywgd2hhdCBpcyBoYXBwZW5pbmcgaGVyZSB0aGUgQ1BVIGNvcmUgaGFzIGFu IG91dHN0YW5kaW5nIFIvVyByZXF1ZXN0Cj4+IGZvciB3aGljaCBpdCBuZXZlciByZWNlaXZlcyBh IHJlc3BvbnNlIGZyb20gdGhlIHJvb3QgcG9ydC4gU28gYmFzaWNhbGx5IGl0cwo+PiBhbiBpbnRl cmNvbm5lY3QgcHJvdG9jb2wgdmlvbGF0aW9uIHRoYXQgdGhlIENQVSBpcyBjb21wbGFpbmluZyBh Ym91dCByYXRoZXIKPj4gdGhhbiBzb21ldGhpbmcgUENJZSBzcGVjaWZpYy4KPiAKPiBDb3VsZCB5 b3UgZGVzY3JpYmUgKGlkZWFsbHkgaW4gY29tbWl0IG1lc3NhZ2UpIHdoaWNoIFNFcnJvciBpcwo+ IHRyaWdnZXJlZD8gTm9ybWFsbHkgaWYga2VybmVsIHJlY2VpdmUgU0Vycm9yIGludGVycnVwdCBp dCBhbHNvIHB1dHMgaW50bwo+IGRtZXNnIG9yIG9vcHMgbWVzc2FnZSBhbHNvIHN5bmRyb21lIGNv ZGUgd2hpY2ggZGVzY3JpYmUgd2hhdCBraW5kIG9mCj4gZXJyb3IgLyBldmVudCBvY2N1cnJlZC4g SXQgY291bGQgaGVscCBhbHNvIHRvIG90aGVyIHVuZGVyc3RhbmQgd2hhdCBpcwo+IGhhcHBlbmlu ZyB0aGVyZS4KPiAKCgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fXwpsaW51eC1hcm0ta2VybmVsIG1haWxpbmcgbGlzdApsaW51eC1hcm0ta2VybmVsQGxpc3Rz LmluZnJhZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5m by9saW51eC1hcm0ta2VybmVsCg==