From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tero Kristo Subject: Re: [PATCHv2 12/19] ARM: OMAP4: PM: update ROM return address for OSWR and OFF Date: Mon, 21 May 2012 12:29:57 +0300 Message-ID: <1337592597.28274.12.camel@sokoban> References: <1336990730-26892-1-git-send-email-t-kristo@ti.com> <1336990730-26892-13-git-send-email-t-kristo@ti.com> <87zk974s1o.fsf@ti.com> Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from arroyo.ext.ti.com ([192.94.94.40]:44154 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932384Ab2EUJaG (ORCPT ); Mon, 21 May 2012 05:30:06 -0400 In-Reply-To: <87zk974s1o.fsf@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Kevin Hilman Cc: linux-omap@vger.kernel.org, paul@pwsan.com, linux-arm-kernel@lists.infradead.org, Carlos Leija , Praneeth Bajjuri , Bryan Buckley On Wed, 2012-05-16 at 16:36 -0700, Kevin Hilman wrote: > Tero Kristo writes: > > > From: Carlos Leija > > > > At wakeup from OFF/OSWR CPU1 will call secure HAL service through a local > > secure dispatcher with MMU off, > > Reviewers who are uninitaited in this level of detail need some more > help here (even those who are deeply familiar will need more help in a > few months when they forget the details.) > > So, some more detail about where this is in the code would be helpful > here. > > > thus ROM will save a PA return address. > > Later in the wakeup, when SMC driver calls an RPC through > > omap4_secure_dispatcher (MMU is on now), > > Again, pointer to where is this in the code would be helpful. I believe this refers to any of the SMC calls done in the ASM files. Most notably the one in omap-headsmp.S, which is added (rather) illogically after this patch in the set though. > > Also, it's not obvious why RPC use used here. Is that referring to the > fact that the secure calls on CPU1 are dispatched to CPU0? Whatever it > means, it should be summarized in the changelog. Not sure about this, maybe security guys can comment on this. > > > ROM code won't log the new return > > address as RPCs are handled different. Thus ROM will attempt to return to > > a PA address when the MMU is on and the system will hang. > > > > We need to do this for OSWR state and OFF state of mpu power domain, > > not just for device off(mpu pd OFF). > > The code suggests that affects *all* OMAP4 revisions? Is that correct? I think thats right. > > And once again, can this be implmented using cluster PM notifiers, where > the notifier is registered only on affected revisions? Should be okay to do that. I guess this should move to omap-secure.c. > > (Sheesh, the number of ROM code workaounds in this series is rather > disconcerting.) > > Kevin > >