From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: Re: [PATCH v3 5/5] ARM: vexpress: DT-based support for CoreTiles Express A5x2 and A9x4 Date: Mon, 5 Dec 2011 17:37:09 +0000 Message-ID: <20111205173709.GA29812@localhost.localdomain> References: <1322579473-8804-1-git-send-email-pawel.moll@arm.com> <1322579473-8804-6-git-send-email-pawel.moll@arm.com> <20111129164050.GC2829@localhost.localdomain> <1322678364.3180.34.camel@hornet.cambridge.arm.com> <20111201122144.GD2026@localhost.localdomain> <1323105880.3147.55.camel@hornet.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1323105880.3147.55.camel-okZbbLrgpR/YkXV2EHHjLW3o5bpOHsLO@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org To: Pawel Moll Cc: "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org On Mon, Dec 05, 2011 at 05:24:40PM +0000, Pawel Moll wrote: > On Thu, 2011-12-01 at 12:21 +0000, Dave Martin wrote: > > That will work, but we should make it clear that this option does not > > provide board support all by itself, maybe: > > > > "Provides common dependencies for VE platforms based on Cortex-A5 or > > Cortex-A9 processors. In order to build a working kernel, you must also > > enable one or more core tile support options." > > Actually, the longer I think about it the more it seems that this code > doesn't support a particular tile, but rather a particular processor... > After all _exactly_ the same code will work with any SMM based on FPGA > Logic Tile (V2F-2XV6), even if it was very different from the coretile, > eg. A9 with RS1 memory map. In such case making it compatible with > V2P-CA9 would be logically wrong... > > I have an idea of spinning the compatible values again to get something > like that: > > compatible = "arm,vexpress-v2p-ca5s", "arm,vexpress-cortex_a5"; > compatible = "arm,vexpress-v2p-ca9", "arm,vexpress-cortex_a9"; > compatible = "arm,vexpress-v2p-ca15", "arm,vexpress-cortex_a15"; The trouble is, node { compatible = x } means "node is an x", not "node has an x". So, we should be careful do document what e.g. arm,vexpress-cortex_a5 actually means. It doesn't mean Cortex-A5, but instead it represents a whole jumble of characteristics which we expect to be common to all vexpress-based A5 platforms. It feels that in practice arm,vexpress-cortex_a5 actually means exactly the same thing as arm,vexpress-v2p-ca5s. Are you sure these two are really independent? (In other words, do we expect multiple different vexpress variants based on A5, and so on?) Cheers ---Dave