From mboxrd@z Thu Jan 1 00:00:00 1970 From: jonathan.austin@arm.com (Jonathan Austin) Date: Tue, 01 Oct 2013 11:29:54 +0100 Subject: [PATCH 2/3] ARM: allow MULTIPLATFORM on no-MMU machines In-Reply-To: <1380534577-15076-3-git-send-email-u.kleine-koenig@pengutronix.de> References: <1380534577-15076-1-git-send-email-u.kleine-koenig@pengutronix.de> <1380534577-15076-3-git-send-email-u.kleine-koenig@pengutronix.de> Message-ID: <524AA422.9040106@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 30/09/13 10:49, Uwe Kleine-K?nig wrote: > There is no technical reason to not use the benefits of MULTIPLATFORM on a > no-MMU machine and my not-yet-mainline efm32 port does work just fine with > it. So drop the dependency. > > Signed-off-by: Uwe Kleine-K?nig > --- > arch/arm/Kconfig | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 0f63a70..d873a34 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -296,8 +296,7 @@ choice > > config ARCH_MULTIPLATFORM > bool "Allow multiple platforms to be selected" > - depends on MMU > - select ARM_PATCH_PHYS_VIRT > + select ARM_PATCH_PHYS_VIRT if MMU && !XIP_KERNEL > select AUTO_ZRELADDR > select COMMON_CLK > select MULTI_IRQ_HANDLER > A patch much like this has been submitted in the past by Arnd and me, and Russell wasn't too happy with the idea because ARCH_MULTIPLATFORM doesn't really make sense for !MMU. However, back then we were talking R/A class. For M-class the memory map is more clearly mandated, the idea of V7M platforms that are ARCH_MULTIPLATFORM compatible is much more feasible. One of the big issues for !MMU/ARCH_MULTIPLATFORM in the past was the need to select the vector configuration at build time - not something we need to worry about with V7M (where we have a configurable vector base), so from that point of view, this change makes sense. But I'm not sure about the XIP_KERNEL part. Once you're using XIP_KERNEL again, multi-platform doesn't make much sense. Uwe, can you correct me on that? Jonny