From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shawn Guo Subject: Re: [PATCH 4/4] ARM: zImage: allow supplementing appended DTB with traditional ATAG data Date: Tue, 21 Jun 2011 15:00:59 +0800 Message-ID: <20110621070058.GA9228@S2101-09.ap.freescale.net> References: <1308632955-11070-1-git-send-email-nico@fluxnic.net> <1308632955-11070-5-git-send-email-nico@fluxnic.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1308632955-11070-5-git-send-email-nico-vtqb6HGKxmzR7s880joybQ@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: Nicolas Pitre Cc: Tony Lindgren , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Tue, Jun 21, 2011 at 01:09:15AM -0400, Nicolas Pitre wrote: > From: Nicolas Pitre > > Some old bootloaders can't be updated to a device tree capable one, > yet they provide ATAGs with memory configuration, the ramdisk address, > the kernel cmdline string, etc. To allow a device tree enabled > kernel to be used with such bootloaders, it is necessary to convert those > ATAGs into FDT properties and fold them into the DTB appended to zImage. > > Currently the following ATAGs are converted: > > ATAG_CMDLINE > ATAG_MEM (up to 8 memory regions) > ATAG_INITRD2 > > If the corresponding information already exists in the appended DTB, it > is replaced, otherwise the required node is created to hold it. > > The code looks for ATAGs at the location pointed by the value of r2 upon > entry into the zImage code. If no ATAGs are found there, an attempt at > finding ATAGs at the typical 0x100 offset from start of RAM is made. > Otherwise the DTB is left unchanged. > > Thisstarted from an older patch from John Bonesio , > with contributions from David Brown . > > Signed-off-by: Nicolas Pitre > --- With this patch applied, I saw nothing coming from kernel on imx51 babbage serial port. -- Regards, Shawn