Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1768490Ab2KORbq (ORCPT ); Thu, 15 Nov 2012 12:31:46 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:55560 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993461Ab2KORbo (ORCPT ); Thu, 15 Nov 2012 12:31:44 -0500 MIME-Version: 1.0 In-Reply-To: <201211151225.31066.arnd@arndb.de> References: <1352973847-21605-1-git-send-email-lee.jones@linaro.org> <20121115112543.GC21682@gmail.com> <201211151225.31066.arnd@arndb.de> Date: Thu, 15 Nov 2012 18:31:43 +0100 Message-ID: Subject: Re: [PATCH 1/2] Boottime: A tool for automatic measurement of kernel/bootloader boot time From: Linus Walleij To: Arnd Bergmann Cc: Lee Jones , Kyungmin Park , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux@arm.linux.org.uk, linus.walleij@stericsson.com, jonas.aberg@stericsson.com, will.deacon@arm.com, Mian Yousaf Kaukab Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1562 Lines: 40 On Thu, Nov 15, 2012 at 1:25 PM, Arnd Bergmann wrote: > On Thursday 15 November 2012, Lee Jones wrote: >> >> > > +/* for automatic boot timing testcases */ >> > > +#define ATAG_BOOTTIME 0x41000403 >> > Where can I refer this ATAG usage? can you point out the reference URL >> > or patches? >> >> I assumed this would be in Mainline u-boot, but apparently not. >> On closer inspection of the internal ST-Ericsson u-boot, this >> functionality appears to be provided by patches which currently >> exist as delta. So in essence, the bootloader you use will have >> to be patched in a similar way for you to retrieve information >> surrounding bootloader boot times. >> >> And there was me thinking it was magic. ;) >> > > And since we're moving away from ATAG on ux500 towards DT, it won't > even work in the future. How essential is this part for the operation > of your code? To be fun we need some mechanism to pass this info from the boot loader to the kernel. I think most bootloaders are already dynamically altering their device trees to put in things like memory size etc so this would probably be done the same way: a standard binding like for everything else, then put the data in there. I don't know if Lee has a modifiable U-boot to try out such concepts on though? Yours, Linus Walleij -- 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/