From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nishanth Menon Subject: Re: AM335x board with disabled RTC crashes Date: Wed, 20 Nov 2013 08:22:59 -0600 Message-ID: <528CC5C3.2010905@ti.com> References: <528CC4CB.4000609@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from comal.ext.ti.com ([198.47.26.152]:38989 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751409Ab3KTOXC (ORCPT ); Wed, 20 Nov 2013 09:23:02 -0500 In-Reply-To: <528CC4CB.4000609@gmail.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Stefan Roese , linux-omap Cc: Tony Lindgren On 11/20/2013 08:18 AM, Stefan Roese wrote: > Hi! > > I'm currently working on a custom AM335x based board, where the SoC > RTC is disabled. As described in this page in the "RTC feature disabled" > column: > > http://processors.wiki.ti.com/index.php/AM335x_Schematic_Checklist#RTC > > On this board the registers of the RTC are not accessible. But the OMAP > hwmod code tries to read the sysc register unconditionally from the RTC. > And this leads to this crash (using v3.12): > > ... > [ 0.179491] CPU: Testing write buffer coherency: ok > [ 0.187702] Setting up static identity map for 0xc04dfa90 - 0xc04dfb00 > [ 0.204665] devtmpfs: initialized > [ 0.219513] VFP support v0.3: implementor 41 architecture 3 part 30 variant c rev 3 > [ 0.237462] *** _update_sysc_cache (263): name=emif > [ 0.246247] omap_hwmod: debugss: _wait_target_disable failed > [ 0.252290] *** _update_sysc_cache (263): name=uart1 > [ 0.257668] *** _update_sysc_cache (263): name=rtc > [ 0.262885] Unhandled fault: external abort on non-linefetch (0x1028) at 0xf9e3e078 > [ 0.270893] Internal error: : 1028 [#1] ARM > [ 0.275302] Modules linked in: > [ 0.278572] CPU: 0 PID: 1 Comm: swapper Not tainted 3.12.0-dirty #21 > [ 0.285222] task: c7047340 ti: c7048000 task.ti: c7048000 > [ 0.290909] PC is at _update_sysc_cache+0x44/0xb0 > [ 0.295861] LR is at _update_sysc_cache+0x1c/0xb0 > ... > > Disabling the RTC in the DT doesn't help (of course). So what's the > recommended way to disable this hwmod access to the RTC registers? http://www.spinics.net/lists/linux-omap/msg98207.html might help you - we had thought it might get queued for 3.12, but it was queued for 3.13 instead.. -- Regards, Nishanth Menon