From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nishanth Menon Subject: Re: [PATCH 09/13] OMAP3: PM: Apply errata i540 before save secure ram Date: Fri, 19 Nov 2010 14:08:50 -0600 Message-ID: <4CE6D952.8000601@ti.com> References: <1290131698-6194-1-git-send-email-nm@ti.com> <1290131698-6194-10-git-send-email-nm@ti.com> <87sjyxb5gh.fsf@deeprootsystems.com> <4CE6B176.10204@ti.com> <87oc9l9juh.fsf@deeprootsystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from na3sys009aog107.obsmtp.com ([74.125.149.197]:34011 "EHLO na3sys009aog107.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753281Ab0KSUIz (ORCPT ); Fri, 19 Nov 2010 15:08:55 -0500 Received: by mail-vw0-f50.google.com with SMTP id 1so2720695vws.23 for ; Fri, 19 Nov 2010 12:08:54 -0800 (PST) In-Reply-To: <87oc9l9juh.fsf@deeprootsystems.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Kevin Hilman Cc: linux-omap , Jean Pihet , Vishwanath Sripathy , Tony Kevin Hilman had written, on 11/19/2010 01:47 PM, the following: > Nishanth Menon writes: > >> Kevin Hilman had written, on 11/19/2010 11:15 AM, the following: >>> Nishanth Menon writes: >>> >>>> From: Eduardo Valentin >>>> >>>> We need to disable the autoidle bit from MPU INTC, >>>> otherwise INTC would get stall, and we would never >>>> come out of WFI. This must be done before save secure ram >>>> as well because save secure ram also does WFI. >>>> >>>> This patch is just a addition to the current W/A we have for i540, >>>> in order to cover the WFI inside the save secure ram. >>> This 'in addition' doesn't really make sense to me. This doesn't add >>> anything to the current workaround, it just changes the order of >>> operations. >> yes - the "in addition" part is as follows: >> >> ideally speaking you just need the omap3_intc_prepare_idle just before >> wfi. we "in addition" need to protect the save_secure_ram call as well >> because ROM code's WFI hits the same window of the bug that we do in >> the kernel. I believe the "in addition" was meant to state that we >> have to protect the logic of romcode as well.. > > OK, then it needs to be rephrased. It doesn't need to (re)summarize the > i540 workaround, since it's already in the kernel. You could just state: > > The existing workaround for erratum i540 (disable MPU INTC auto-idle) > needs to be done before saving secure RAM since secure-mode call can > also do WFI. > yep, Thanks, this is indeed a better description - will take it in as part of my v2. -- Regards, Nishanth Menon