From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Date: Sat, 28 Nov 2015 12:33:28 +0000 Message-ID: <20151128123328.GC30871@n2100.arm.linux.org.uk> References: <20150713131902.GH26485@atomide.com> <20151127132722.GA30871@n2100.arm.linux.org.uk> <20151127195148.GB30871@n2100.arm.linux.org.uk> <11537945.4HX4Y84tjV@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Nicolas Pitre Cc: Arnd Bergmann , linux-arm-kernel@lists.infradead.org, Pali =?iso-8859-1?Q?Roh=E1r?= , "devicetree@vger.kernel.org" , Ivaylo Dimitrov , Laura Abbott , Tony Lindgren , Sebastian Reichel , Will Deacon , linux-kernel@vger.kernel.org, Rob Herring , Pavel Machek , Grant Likely , linux-omap@vger.kernel.org, Frank Rowand , Andreas =?iso-8859-1?Q?F=E4rber?= List-Id: devicetree@vger.kernel.org On Fri, Nov 27, 2015 at 06:28:50PM -0500, Nicolas Pitre wrote: > On Fri, 27 Nov 2015, Arnd Bergmann wrote: > > > I don't mind creating the /proc/atags compatibility hack from the kernel > > for a DT based N700 kernel, as long as we limit it as much as we can > > to the machines that need it. Leaving a board file for the N700 in place > > that contains the procfs code (and not much more) seems reasonable > > here, as we are talking about a board specific hack and the whole point > > appears to be running unmodified user space. > > > > Regarding how to get the data into the kernel in the first place, my > > preferred choice would still be to have an intermediate bootloader > > such as pxa-impedance-matcher, but I won't complain if others are > > happy enough about putting it into the ATAGS compat code we already > > have, as long as it's limited to the boards we know need it. > > Assuming you have a N700 board file for special procfs code, then why > not getting at the atags in memory where the bootloader has put them > directly from that same board file? This way it'll really be limited to > the board we know needs it and the special exception will be contained > to that one file. Amongst the machine specific hooks, there is one that > gets invoked early during boot before those atags are overwritten. I've already suggested that. -- FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.