From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Wed, 26 Mar 2014 00:42:23 +0100 Subject: [PATCH 44/62] ARM: integrator: refine CPU selection In-Reply-To: References: <1395257399-359545-1-git-send-email-arnd@arndb.de> <201403201148.16239.arnd@arndb.de> Message-ID: <4776688.CZBeEWFJox@wuerfel> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tuesday 25 March 2014 21:34:21 Linus Walleij wrote: > On Thu, Mar 20, 2014 at 11:48 AM, Arnd Bergmann wrote: > > > Nevermind, I'll drop this patch for now, I just had an idea to do it > > better: Since Linus and I are trying to get Integrator and Realview > > moved over into ARCH_MULTIPLATFORM anyway, I'll defer the CPU selection > > question until that's done. > > Integrator is blocked by one single thing: > bus_to_virt/virt_to_bus. > > If we can get some consensus on Santosh's patches > (or however we want to solve that) I'll do multiplatform for > Integrator any day. Yes, I know. My point is that once the two are multiplatform, we wouldn't do the CPU selection patches like this anymore. Instead, I would just do config CPU_ARM920T bool "Support ARM920T processor" if ARCH_MULTI_V4T ... config CPU_ARM926T bool "Support ARM920T processor" if ARCH_MULTI_V5 ... ... In a multiplatform kernel, there is nothing wrong with just letting users turn on arbitrary combinations of CPUs as long as they are compatible at run-time (i.e. not v5+v7 combined). This will also let you run qemu images using the MACH_VIRT target and any CPU emulation. Of course, most platforms will still select the CPUs they actually use, but you can always add more. Arnd