From mboxrd@z Thu Jan 1 00:00:00 1970 From: jgunthorpe@obsidianresearch.com (Jason Gunthorpe) Date: Wed, 27 Aug 2014 09:58:44 -0600 Subject: [PATCH v7 3/8] cpufreq: kirkwood: Remove use of the clk provider API In-Reply-To: <20140826233008.5251.50447@quantum> References: <1408375833-10703-1-git-send-email-tomeu.vizoso@collabora.com> <1408375833-10703-4-git-send-email-tomeu.vizoso@collabora.com> <20140820225513.5251.284@quantum> <53F5A587.9030200@collabora.com> <20140821133825.GH8608@lunn.ch> <20140822192933.5251.53733@quantum> <20140822201112.GH17277@lunn.ch> <20140826214631.5251.66177@quantum> <20140826223637.GA5324@lunn.ch> <20140826233008.5251.50447@quantum> Message-ID: <20140827155844.GA911@obsidianresearch.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Aug 26, 2014 at 04:30:08PM -0700, Mike Turquette wrote: > 2) for the kexec-kernel-case, the responsibility is on the first kernel > to set things up in a good state for the second kernel, with the > exception of using kexec to debug/examime/recover from a kernel crash, > in which case you likely don't care about this stuff as much FWIW, we frequently use a kexec flow on Kirkwood for development here - and I have not been able to get the initial kernel to cleanly shut down before kexec'ing the second kernel. The flow we've had to use involved including a pre-kernel stub in the kexec flow that goes around and cleans up all the registers enough so that the 2nd kernel will work properly. Critically it does things like turn off ethernet DMA, because the initial kernel won't even do that :| There is some kind of support for doing this, but I ran out of time unraveling the mess of config options to actually turn it on for kirkwood.. It is tied to PM support which was/is missing elements on Kirkwood.. Jason From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935209AbaH0P7J (ORCPT ); Wed, 27 Aug 2014 11:59:09 -0400 Received: from quartz.orcorp.ca ([184.70.90.242]:57394 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934686AbaH0P7H (ORCPT ); Wed, 27 Aug 2014 11:59:07 -0400 Date: Wed, 27 Aug 2014 09:58:44 -0600 From: Jason Gunthorpe To: Mike Turquette Cc: Andrew Lunn , Tomeu Vizoso , Stephen Warren , Viresh Kumar , Peter De Schrijver , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, Javier Martinez Canillas , Rabin Vincent , Thierry Reding , Tomasz Figa , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v7 3/8] cpufreq: kirkwood: Remove use of the clk provider API Message-ID: <20140827155844.GA911@obsidianresearch.com> References: <1408375833-10703-1-git-send-email-tomeu.vizoso@collabora.com> <1408375833-10703-4-git-send-email-tomeu.vizoso@collabora.com> <20140820225513.5251.284@quantum> <53F5A587.9030200@collabora.com> <20140821133825.GH8608@lunn.ch> <20140822192933.5251.53733@quantum> <20140822201112.GH17277@lunn.ch> <20140826214631.5251.66177@quantum> <20140826223637.GA5324@lunn.ch> <20140826233008.5251.50447@quantum> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140826233008.5251.50447@quantum> User-Agent: Mutt/1.5.21 (2010-09-15) X-Broken-Reverse-DNS: no host name found for IP address 10.0.0.161 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 26, 2014 at 04:30:08PM -0700, Mike Turquette wrote: > 2) for the kexec-kernel-case, the responsibility is on the first kernel > to set things up in a good state for the second kernel, with the > exception of using kexec to debug/examime/recover from a kernel crash, > in which case you likely don't care about this stuff as much FWIW, we frequently use a kexec flow on Kirkwood for development here - and I have not been able to get the initial kernel to cleanly shut down before kexec'ing the second kernel. The flow we've had to use involved including a pre-kernel stub in the kexec flow that goes around and cleans up all the registers enough so that the 2nd kernel will work properly. Critically it does things like turn off ethernet DMA, because the initial kernel won't even do that :| There is some kind of support for doing this, but I ran out of time unraveling the mess of config options to actually turn it on for kirkwood.. It is tied to PM support which was/is missing elements on Kirkwood.. Jason