Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753352AbaAXPoU (ORCPT ); Fri, 24 Jan 2014 10:44:20 -0500 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:49191 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752728AbaAXPoS (ORCPT ); Fri, 24 Jan 2014 10:44:18 -0500 Date: Fri, 24 Jan 2014 15:44:17 +0000 From: Mark Rutland To: Catalin Marinas Cc: Hanjun Guo , Linus Walleij , "Rafael J. Wysocki" , Will Deacon , Russell King - ARM Linux , ACPI Devel Maling List , "linux-arm-kernel@lists.infradead.org" , "grant.likely@linaro.org" , Matthew Garrett , Olof Johansson , Bjorn Helgaas , Rob Herring , Arnd Bergmann , Patch Tracking , "linux-kernel@vger.kernel.org" , linaro-kernel , "linaro-acpi@lists.linaro.org" , Charles Garcia-Tobin , Amit Daniel Kachhap Subject: Re: [PATCH 18/20] clocksource / acpi: Add macro CLOCKSOURCE_ACPI_DECLARE Message-ID: <20140124154417.GB4758@e106331-lin.cambridge.arm.com> References: <1389961514-13562-1-git-send-email-hanjun.guo@linaro.org> <1389961514-13562-19-git-send-email-hanjun.guo@linaro.org> <20140122114537.GA15591@e106331-lin.cambridge.arm.com> <52E1B1DE.5050507@linaro.org> <20140124120815.GH814@e106331-lin.cambridge.arm.com> <20140124151513.GD19052@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140124151513.GD19052@arm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 24, 2014 at 03:15:13PM +0000, Catalin Marinas wrote: > Do we still need the chosen node to be passed via DT for command line, > even if the kernel uses ACPI? It depends on how the kernel is booted. If not booted as a UEFI application, then the user would have to provide a dtb to pass the command line. If booted as a UEFI application, the kernel can retrieve the commandline from UEFI and handle it appropriately (this _might_ involve the EFI stub building a dtb with a chosen node and pasing that to the kernel, but that could change as it's within the kernel). In that case, the user need not build a dtb manually. However, I'd expect that we use a restricted dtb with only a /chosen node for passing additional data as an equivalent to x86's bootargs (which would contain the location of ACPI tables and possibly other stuff like initrd location if not passed on the command line). That makes the very early logic in the kernel much simpler, and it gives us an extensible format that should limit headaches in future. So if booted with ACPI we _might_ have a restricted chosen-only dtb, which _might_ be passed to the kernel explicitly by the user. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/