From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga03.intel.com ([143.182.124.21]) by linuxtogo.org with esmtp (Exim 4.72) (envelope-from ) id 1UNQKQ-00066X-Il for openembedded-core@lists.openembedded.org; Wed, 03 Apr 2013 18:14:29 +0200 Received: from azsmga001.ch.intel.com ([10.2.17.19]) by azsmga101.ch.intel.com with ESMTP; 03 Apr 2013 08:57:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,402,1363158000"; d="scan'208";a="280260806" Received: from unknown (HELO envy.home) ([10.255.13.219]) by azsmga001.ch.intel.com with ESMTP; 03 Apr 2013 08:57:13 -0700 Message-ID: <515C5159.6030200@linux.intel.com> Date: Wed, 03 Apr 2013 08:57:13 -0700 From: Darren Hart User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: "Maupin, Chase" References: <1364575688-19681-1-git-send-email-Chase.Maupin@ti.com> <515B455E.4030504@linux.intel.com> <7D46E86EC0A8354091174257B2FED101594BAE12@DLEE11.ent.ti.com> In-Reply-To: <7D46E86EC0A8354091174257B2FED101594BAE12@DLEE11.ent.ti.com> X-Enigmail-Version: 1.5.1 Cc: "Ashfield, Bruce" , "openembedded-core@lists.openembedded.org" Subject: Re: [PATCH] linux-dtb: Add simple DTB symlinks for devicetree X-BeenThere: openembedded-core@lists.openembedded.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: Patches and discussions about the oe-core layer List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Apr 2013 16:14:34 -0000 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit On 04/03/2013 07:20 AM, Maupin, Chase wrote: >> -----Original Message----- >> From: Darren Hart [mailto:dvhart@linux.intel.com] >> Sent: Tuesday, April 02, 2013 3:54 PM >> To: Maupin, Chase >> Cc: openembedded-core@lists.openembedded.org; Ashfield, Bruce >> Subject: Re: [OE-core] [PATCH] linux-dtb: Add simple DTB symlinks >> for devicetree >> >> >> >> On 03/29/2013 09:48 AM, Chase Maupin wrote: >>> * This is similar to the symlinks provided for the kernel image >>> in the /boot directory of a file system. The goal is to have >>> simply named symlinks in /boot that mirror the device tree >>> name in the kernel sources. This is so that programs like >>> U-Boot can easily find the default device tree binary in the >>> /boot directory and use that when booting the kernel. >>> * Use update-alternatives to handle proper creation and removal >>> of the symlinks. >> >> Hi Chase, >> >> So I have no experience myself with Device Tree. Adding Bruce A. >> for some >> additional review. >> >> I am going to assume this is the right thing to do for u-boot >> systems. >> Which devices have you verified this as working with? > > OMAP5 uEVM and AM335x EVM. For these devices U-Boot does a simple extload from the /boot directory of the dtb. The goal here is to have the dtb name in /boot match the name that would be generated when you build the dtb in the kernel. > > For example the omap5-uevm.dts file is compiled as omap5-uevm.dtb. So using a symlink with this standard naming makes it easier for u-boot to detect the device it is running on and look for the standard file name vs devicetree-uImage-omap5-evm.dtb. > > Also, for people that want to load the dtb from other locations such as a different partition on the SD card they can still just copy the dtb file from the kernel build and not need to modify u-boot to use the different file name, just the location. And what about the comments on your patch itself below? > >> >>> >>> Signed-off-by: Chase Maupin >>> --- >>> meta/recipes-kernel/linux/linux-dtb.inc | 20 >> ++++++++++++++++++++ >>> 1 files changed, 20 insertions(+), 0 deletions(-) >>> >>> diff --git a/meta/recipes-kernel/linux/linux-dtb.inc >> b/meta/recipes-kernel/linux/linux-dtb.inc >>> index ec6c375..66cf255 100644 >>> --- a/meta/recipes-kernel/linux/linux-dtb.inc >>> +++ b/meta/recipes-kernel/linux/linux-dtb.inc >>> @@ -45,3 +45,23 @@ do_deploy_append() { >>> done >>> fi >>> } >>> + >>> +pkg_postinst_kernel-devicetree () { >> >> Please use tabs for bash functions. Oddly, I see the only tabs in >> this >> file are in the anonymous python blocks. Doh. >> >>> + cd /${KERNEL_IMAGEDEST} >>> + for DTS_FILE in ${KERNEL_DEVICETREE} >>> + do >>> + DTS_BASE_NAME=`basename ${DTS_FILE} | awk -F "." >> '{print $1}'` >>> + DTB_NAME="devicetree-uImage-${DTS_BASE_NAME}.dtb" >> >> >> Is "uImage" always correct here? Or should we be using >> ${KERNEL_IMAGETYPE} here? >> >> >>> + update-alternatives --install >> /${KERNEL_IMAGEDEST}/${DTS_BASE_NAME}.dtb ${DTS_BASE_NAME}.dtb >> ${DTB_NAME} ${KERNEL_PRIORITY} || true >>> + done >>> +} >>> + >>> +pkg_postrm_kernel-devicetree () { >>> + cd /${KERNEL_IMAGEDEST} >>> + for DTS_FILE in ${KERNEL_DEVICETREE} >>> + do >>> + DTS_BASE_NAME=`basename ${DTS_FILE} | awk -F "." >> '{print $1}'` >>> + DTB_NAME="devicetree-uImage-${DTS_BASE_NAME}.dtb" >>> + update-alternatives --remove ${DTS_BASE_NAME}.dtb >> ${DTB_NAME} ${KERNEL_PRIORITY} || true >>> + done >>> +} >>> >> >> Thanks, >> >> -- >> Darren Hart >> Intel Open Source Technology Center >> Yocto Project - Technical Lead - Linux Kernel -- Darren Hart Intel Open Source Technology Center Yocto Project - Technical Lead - Linux Kernel