From mboxrd@z Thu Jan 1 00:00:00 1970 From: Colin Cross Subject: Re: [PATCH v2 04/28] ARM: mm: cache-l2x0: Add support forre-enabling l2x0 Date: Sat, 5 Feb 2011 10:36:22 -0600 Message-ID: References: <1295834493-5019-5-git-send-email-ccross@android.com> <1295968464.10109.264.camel@e102109-lin.cambridge.arm.com> <20110125154133.GB17280@n2100.arm.linux.org.uk> <1295979242.10109.308.camel@e102109-lin.cambridge.arm.com> <2f97ec8a084e590220e1548fc927b60e@mail.gmail.com> <-8932138696981683633@unknownmsgid> <20110204234331.GF8732@n2100.arm.linux.org.uk> <1bebe4b5c8590059b70a146d5486fa6a@mail.gmail.com> <20110205094730.GA23965@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Santosh Shilimkar Cc: Russell King - ARM Linux , Will Deacon , Catalin Marinas , Linus Walleij , konkers@android.com, Tony Lindgren , linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, olof@lixom.net, linux-arm-kernel@lists.infradead.org List-Id: linux-tegra@vger.kernel.org On Sat, Feb 5, 2011 at 4:41 AM, Santosh Shilimkar wrote: >> -----Original Message----- >> From: Russell King - ARM Linux [mailto:linux@arm.linux.org.uk] >> Sent: Saturday, February 05, 2011 3:18 PM >> To: Santosh Shilimkar >> Cc: Colin Cross; Will Deacon; Catalin Marinas; Linus Walleij; >> konkers@android.com; Tony Lindgren; linux-kernel@vger.kernel.org; >> linux-tegra@vger.kernel.org; olof@lixom.net; linux-arm- >> kernel@lists.infradead.org >> Subject: Re: [PATCH v2 04/28] ARM: mm: cache-l2x0: Add support >> forre-enabling l2x0 >> >> On Sat, Feb 05, 2011 at 01:21:24PM +0530, Santosh Shilimkar wrote: >> > GIC save/restore on OMAP follows different strategy. There is a >> > Predefined layout to save content and restore is done atomically >> > by boot ROM code. >> > L2 cache also same case. Only AUXCTRL needs to be programmed on >> > wakeup from low power mode and that too with secure call. Rest >> > of the registers are managed by boot ROM code. >> > >> > TWD is already managed through framework. Othe CPU low power >> > sequence is very small and OMAP has restrictions on the last >> > core to go down and first to wakeup. >> > >> > So at least I don't see any use of common notifiers for GIC >> > and L2 will help OMAP lower power code. >> >> What this means is that we're going to end up littering things like >> GIC >> and other stuff with lots of individual SoC specific code to save >> state >> into individual SoC specific structures. =A0This is not sane, and >> we're >> not going to corrupt generic code with SoC specific code. > > Fully agree and hence flagged it early. > > Regards, > Santosh > Would putting dummy values in the areas the boot ROM uses and then letting the common GIC code restore over them cause any problems? From mboxrd@z Thu Jan 1 00:00:00 1970 From: ccross@android.com (Colin Cross) Date: Sat, 5 Feb 2011 10:36:22 -0600 Subject: [PATCH v2 04/28] ARM: mm: cache-l2x0: Add support forre-enabling l2x0 In-Reply-To: References: <1295834493-5019-5-git-send-email-ccross@android.com> <1295968464.10109.264.camel@e102109-lin.cambridge.arm.com> <20110125154133.GB17280@n2100.arm.linux.org.uk> <1295979242.10109.308.camel@e102109-lin.cambridge.arm.com> <2f97ec8a084e590220e1548fc927b60e@mail.gmail.com> <-8932138696981683633@unknownmsgid> <20110204234331.GF8732@n2100.arm.linux.org.uk> <1bebe4b5c8590059b70a146d5486fa6a@mail.gmail.com> <20110205094730.GA23965@n2100.arm.linux.org.uk> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sat, Feb 5, 2011 at 4:41 AM, Santosh Shilimkar wrote: >> -----Original Message----- >> From: Russell King - ARM Linux [mailto:linux at arm.linux.org.uk] >> Sent: Saturday, February 05, 2011 3:18 PM >> To: Santosh Shilimkar >> Cc: Colin Cross; Will Deacon; Catalin Marinas; Linus Walleij; >> konkers at android.com; Tony Lindgren; linux-kernel at vger.kernel.org; >> linux-tegra at vger.kernel.org; olof at lixom.net; linux-arm- >> kernel at lists.infradead.org >> Subject: Re: [PATCH v2 04/28] ARM: mm: cache-l2x0: Add support >> forre-enabling l2x0 >> >> On Sat, Feb 05, 2011 at 01:21:24PM +0530, Santosh Shilimkar wrote: >> > GIC save/restore on OMAP follows different strategy. There is a >> > Predefined layout to save content and restore is done atomically >> > by boot ROM code. >> > L2 cache also same case. Only AUXCTRL needs to be programmed on >> > wakeup from low power mode and that too with secure call. Rest >> > of the registers are managed by boot ROM code. >> > >> > TWD is already managed through framework. Othe CPU low power >> > sequence is very small and OMAP has restrictions on the last >> > core to go down and first to wakeup. >> > >> > So at least I don't see any use of common notifiers for GIC >> > and L2 will help OMAP lower power code. >> >> What this means is that we're going to end up littering things like >> GIC >> and other stuff with lots of individual SoC specific code to save >> state >> into individual SoC specific structures. ?This is not sane, and >> we're >> not going to corrupt generic code with SoC specific code. > > Fully agree and hence flagged it early. > > Regards, > Santosh > Would putting dummy values in the areas the boot ROM uses and then letting the common GIC code restore over them cause any problems?