From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [GIT PULL] for testing: OMAP hwmod driver conversions: watchdog, UART, i2c Date: Fri, 01 Oct 2010 08:07:04 -0700 Message-ID: <87k4m2c5pj.fsf@deeprootsystems.com> References: <8762xpenf8.fsf@deeprootsystems.com> <20100928201844.GI3117@atomide.com> <87tyl8rxwp.fsf@deeprootsystems.com> <20100930021819.GD3117@atomide.com> <877hi3i9cp.fsf@deeprootsystems.com> <87pqvvgt8g.fsf@deeprootsystems.com> <877hi3gqq7.fsf@deeprootsystems.com> <0680EC522D0CC943BC586913CF3768C003FF2DAF74@dbde02.ent.ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pw0-f46.google.com ([209.85.160.46]:34257 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753010Ab0JAPHG (ORCPT ); Fri, 1 Oct 2010 11:07:06 -0400 Received: by pwj5 with SMTP id 5so573316pwj.19 for ; Fri, 01 Oct 2010 08:07:06 -0700 (PDT) In-Reply-To: <0680EC522D0CC943BC586913CF3768C003FF2DAF74@dbde02.ent.ti.com> (Rajendra Nayak's message of "Fri, 1 Oct 2010 18:58:43 +0530") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Nayak, Rajendra" Cc: Tony Lindgren , "linux-omap@vger.kernel.org" , "Varadarajan, Charulatha" , "Raja, Govindraj" "Nayak, Rajendra" writes: [...] >> >> >> >> Hmm, this fault is very early and long before any PM code has >> >> initialzed. I suspect this happens with the master branch too ?? >> > >> > I've reproduced this now, and it doesn't happen on the master branch and >> > only happens after merge pm-hwmods. >> > >> > Debugging now... >> >> OK, so this failure is (somehow) related to the i2c hwmods, but I did >> not figure out how. Rajendra, can you dig into this? It only seems to >> happen on 2420/n800, and all other platforms seem OK. > > Hi Kevin, > > I was able to reproduce the crash on the n800 and have been debugging > it for a while. Like you said putting a HWMOD_INIT_NO_RESET did not > seem to fix it for me, and the only way I can get the n800 to > completely bootup is by removing the sysc completely for i2c. That is > quite surprising since the only thing that can be done using the > sysconfig on omap2420 is a softreset. > > I verified that its not the sysc read itself that causes a crash > (clocks seem to be enabled, idlest seems fine) but somehow just these > sysc reads (if I have HWMOD_INIT_NO_RESET set) seem to be enough to > cause the crash. Nothing gets written back to the sysc register > either. I was suspecting the omap_readl's done in hmwod framework on > the 16bit 2420 registers to be an issue, but I am yet to figure out > how. > > I am debugging this further, but in the meantime since this is gating > all other patches to get merged in omap-testing, should I just remove > the sysc for i2c on 2420? The only thing it will prevent is a i2c > softreset at boot, which anyway does not seem to be causing any issues > on n800. For omap-testing, I will just drop the i2c series for now until this is better understood. Happy debugging! this sounds like a tricky one, Kevin