From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-o-3.desy.de ([131.169.56.156]:55671 "EHLO smtp-o-3.desy.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755248AbbA2B04 (ORCPT ); Wed, 28 Jan 2015 20:26:56 -0500 Received: from smtp-map-3.desy.de (smtp-map-3.desy.de [131.169.56.68]) by smtp-o-3.desy.de (DESY-O-3) with ESMTP id A9570280322 for ; Wed, 28 Jan 2015 08:51:38 +0100 (CET) Received: from ZITSWEEP2.win.desy.de (zitsweep2.win.desy.de [131.169.97.96]) by smtp-map-3.desy.de (DESY_MAP_3) with ESMTP id 9A77A10DF for ; Wed, 28 Jan 2015 08:51:37 +0100 (MET) Message-ID: <54C89508.3080001@desy.de> Date: Wed, 28 Jan 2015 08:51:36 +0100 From: Ludwig Petrosyan MIME-Version: 1.0 To: Bjorn Helgaas CC: Paulo Fortuna Carvalho , "linux-pci@vger.kernel.org" , Greg Kroah-Hartman Subject: Re: Hot add a PCIe device driver upon hotplug event References: <20150122222016.GF13072@google.com> <54C5EF11.8070604@desy.de> In-Reply-To: Content-Type: text/plain; charset=utf-8 Sender: linux-pci-owner@vger.kernel.org List-ID: Hi Bjorn yes this that are refer, more detailed version was in previous Workshop https://indico.desy.de/getFile.py/access?contribId=5&sessionId=1&resId=0&materialId=slides&confId=7866 and additionally was presentation about driver part https://indico.desy.de/getFile.py/access?contribId=32&sessionId=9&resId=0&materialId=slides&confId=10329 I hope this will help and may be I will get some feedback to improve both and fix bugs Cheers Ludwig On 01/27/2015 05:50 PM, Bjorn Helgaas wrote: > Hi Ludwig, > > Thanks a lot for the pointers to MTCA information. I found > presentation slides here: > https://indico.desy.de/getFile.py/access?contribId=33&sessionId=0&resId=1&materialId=slides&confId=10329, > which I assume is that you're referring to. > > On Mon, Jan 26, 2015 at 1:38 AM, Ludwig Petrosyan > wrote: >> Hello >> >> (I have send this email two days ago but got status undeliverable, so try to >> send it again) >> >> We had the same problem on the MTCA system years ago, but now the problem is >> solved. >> The MTCA system is a kind of ATCA and I think attention Button problem could >> be solved in the same way. >> Ok, now what we have done: >> First of all the main difference of the ATCA or MTCA PCIe system is what the >> PCIe Switch which responsible for the HotPlug >> >> (I mean Switch which is connected to the crate slots, and hotplug >> controllers of this are used in hotpluging ) and the Attention Button of the >> >> PCIe slot reside on the different boards (usually PCIe Switch is on the >> Crate Manager board and Attention Button is the AMC module Latch ), >> >> So there are no any wired connections between Attention Button and PCIe >> Switch. Than user pool out the AMC module Latch the PCIe Switch has no idea >> >> about that, BUT the AMC module controller (MMC) sends IPMI message to the >> Crate Management Controller (MCMC) >> and MCMC starts AMC powering down procedures. The idea was: usually MCMC and >> PCIe Switch reside on the same board and MCMC getting IPMI message >> >> about state change of the AMC Latch (latch polled out or pressed) set >> appropriate registers of the PCIe Switch or push high appropriate lines of >> the PCIe Switch >> >> and PCIe Switch gets information that Attention Button is pressed and send >> hotplug interrupt to the hotplug driver. >> This approach works in our MTCA systems and we have a full working PCIe >> HotPlug. > It sounds like you basically have some IPMI glue between the the AMC > latch and the PCIe Attention Button, and from the point of view of the > pciehp (PCIe native hotplug) driver, it just sees a normal Attention > Button. That sounds like a reasonable thing to do. > > In Paulo's case, it sounds like there is some sort of switch related > to the card, but the IPMI or similar glue that could potentially lead > to the Attention Button line doesn't exist. In that case, pciehp > doesn't know anything about the switch. If there's some other way, > e.g., IPMI, to learn about the switch, maybe that could be done via a > separate driver. > >> More detailed information one can get to look documents of the MTCA Workshop >> (http://mtcaws.desy.de/) in tutorial section was presentation about >> >> PCIe Hotplug, or look in PICMIG recommendation (there is new recommendation >> about PCIe HotPlug for MTC.4) >> >> With best regards >> >> Ludwig Petrosyan >> >>