From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Austin Subject: Re: [PATCH v2] ARM: new platform for Energy Micro's EFM32 Cortex-M3 SoCs Date: Tue, 01 Oct 2013 11:38:16 +0100 Message-ID: <524AA618.20307@arm.com> References: <1379447884-14025-1-git-send-email-u.kleine-koenig@pengutronix.de> <201309172245.25367.arnd@arndb.de> <20130926094251.GK16106@pengutronix.de> <201309272344.01386.arnd@arndb.de> <20130928191511.GA2548@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20130928191511.GA2548-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: =?UTF-8?B?VXdlIEtsZWluZS1Lw7ZuaWc=?= Cc: Arnd Bergmann , Olof Johansson , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org" List-Id: devicetree@vger.kernel.org On 28/09/13 20:15, Uwe Kleine-K=C3=B6nig wrote: > Hi Arnd, > > On Fri, Sep 27, 2013 at 11:44:01PM +0200, Arnd Bergmann wrote: >> On Thursday 26 September 2013, Uwe Kleine-K=C3=B6nig wrote: [...] >> * An ARMv7-M kernel cannot run on either ARMv4/v5 nor ARMv6/v7-A, ri= ght? > The entry convention is different (ARMv7-M doesn't support the ARM > instruction set but you need to jump into the kernel in ARM mode for > v4-v7). Other that that I don't know if there is a problem. Maybe > Jonathan can say anything here? There's a more fundamental difference between V7M and other things=20 before it - V7M uses a different exception model (We don't have the ide= a=20 of SVC, USR, IRQ, FIQ etc, instead it is Thread/Process/Handler modes). So no, V7M is V7M, I'm afraid. > Or alternatively if you want an efm32 > devboard, just tell me. They're cool, I can recommend one ;) > >> Do you prevent building such a kernel in Kconfig? > I'm sure my Kconfig magic isn't waterproof. It took me a few tries to > expand the multiarch architecture selection to make v7-m selectable a= t > all. There's a patch series I posted in the past for !MMU with Vexpress that= =20 was a way to have a !MMU without changing the ARCH_MULTIPLATFORM=20 configuration: http://lists.infradead.org/pipermail/linux-arm-kernel/2013-May/168106.h= tml You could take a look at that as an alternative approach, but the other= =20 series you've sent looks reasonable from a !MMU/Multiplatform point of=20 view, I'm just not sure about the XIP stuff. Jonny -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html