From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH v3 03/12] bus: mvebu-mbus: Add static window allocation to the DT binding Date: Tue, 18 Jun 2013 12:47:53 -0600 Message-ID: <20130618184753.GA6090@obsidianresearch.com> References: <1371554737-25319-1-git-send-email-ezequiel.garcia@free-electrons.com> <20130618174622.GD2204@obsidianresearch.com> <51C0A5F8.8030300@gmail.com> <201306182039.50736.arnd@arndb.de> <51C0AA8E.9080807@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <51C0AA8E.9080807-Re5JQEeQqe8AvxtiuMwx3w@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" To: Sebastian Hesselbarth Cc: Lior Amsalem , Andrew Lunn , Jason Cooper , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Maen Suleiman , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Tue, Jun 18, 2013 at 08:44:30PM +0200, Sebastian Hesselbarth wrote: > On 06/18/2013 08:39 PM, Arnd Bergmann wrote: > >On Tuesday 18 June 2013, Sebastian Hesselbarth wrote: > >>Also allows you to have up to 40b offset, which might be important > >>with LPAE enabled. > > > >Not with the current generation I think, since the mbus windows are > >32 bit only, but it would avoid having to come up with a new format > >for a potential future-generation mbus that has wider address. > > Yeah, I also recall Thomas or Gregory mention a 32b limitation in > remap windows. But we don't need to waste addresses here > > And even if SIAA0000 is a concern because there may be target id >15 > someday, we can still have IIAASS00 instead of IIAA00SS. I guess > LPAE will not rise above 40b quickly ;) S = 0 means 4 bit I, 8 bit A S = F means special S = 1 could mean 16 bit I, etc , etc Yes, we could define things as 'SIAAoooo oooooooo' But remember 'o' is the offset within the window, it is not related to LPAE. To need > 32 bits 'o' you need to have windows > 4G in size. The only thing that could possibly do that is PCI-E, and it is all special anyhow.. The mbus top level ranges remap already supports >4G locations for the windows, even though current hardware cannot do that. Jason