meta-intel ========== This README file contains information on building and booting meta-intel BSP layers. Please see the corresponding sections below for details. Yocto Project Compatible ======================== The BSPs contained in this layer are compatible with the Yocto Project as per the requirements listed here: Dependencies ============ This layer depends on: URI: git:// branch: master URI: git:// layers: meta branch: master Table of Contents ================= I. Overview II. Building and booting meta-intel BSP layers a. Building the intel-common BSP layers b. Booting the intel-common BSP images III. Technical Miscellany Benefits of using meta-intel The intel-common kernel package architecture Intel-specific machine features IV. Tested Hardware V. Guidelines for submitting patches I. Overview =========== This is the location for Intel-maintained BSPs. For details on the intel-common, see the information below. For all others, please see the README files contained in the individual BSP layers for BSP-specific information. If you have problems with or questions about a particular BSP, please contact the maintainer listed in the MAINTAINERS file directly (cc:ing the Yocto mailing list puts it in the archive and helps other people who might have the same questions in the future), but please try to do the following first: - look in the Yocto Project Bugzilla ( to see if a problem has already been reported - look through recent entries of the meta-intel ( and Yocto ( mailing list archives to see if other people have run into similar problems or had similar questions answered. If you believe you have encountered a bug, you can open a new bug and enter the details in the Yocto Project Bugzilla ( If you're relatively certain that it's a bug against the BSP itself, please use the 'Yocto Project Components: BSPs | meta-intel' category for the bug; otherwise, please submit the bug against the most likely category for the problem - if you're wrong, it's not a big deal and the bug will be recategorized upon triage. II. Building and booting meta-intel BSP layers ============================================== The following sections contain information on building and booting the BSPs contained in the meta-intel layer. Note that these instructions specifically cover the intel-common, which may or may not be applicable to other BSPs contained in this layer - if a given BSP contains its own README, that version should be used instead, and these instructions can be ignored. a. Building the intel-common BSP layers ------------------------------------------------- In order to build an image with BSP support for a given release, you need to download the corresponding BSP tarball from the 'Board Support Package (BSP) Downloads' page of the Yocto Project website (or equivalently, check out the appropriate branch from the meta-intel git repository, see below). For the intel-common BSPs, those tarballs would correspond to the following choices in the BSP downloads section: - Intel-core2-32 Intel® Common Core BSP (Intel-core2-32) - Intel-corei7-64 Intel® Common Core BSP (Intel-corei7-64) The intel-* BSPs, also known as the intel-common BSPs, provide a few carefully selected tune options and generic hardware support to cover the majority of current Intel CPUs and devices. The naming follows the convention of intel--, where TUNE is the gcc cpu-type (used with mtune and march typically) and BITS is either 32 bit or 64 bit. Having done that, and assuming you extracted the BSP tarball contents at the top-level of your yocto build tree, you can build a BSP image by adding the location of the meta-intel layer to bblayers.conf e.g.: yocto/meta-intel \ To enable a particular machine, you need to add a MACHINE line naming the BSP to the local.conf file: MACHINE ?= "xxx" where 'xxx' is replaced by one of the following BSP names: - intel-core2-32 This BSP is optimized for the Core2 family of CPUs as well as all Atom CPUs prior to the Silvermont core. - intel-corei7-64 This BSP is optimized for Nehalem and later Core and Xeon CPUs as well as Silvermont and later Atom CPUs, such as the Baytrail SoCs. You should then be able to build an image as such: $ source oe-init-build-env $ bitbake core-image-sato At the end of a successful build, you should have an image that you can boot from a USB flash drive (see instructions on how to do that below, in the section 'Booting the intel-common BSP images'). As an alternative to downloading the BSP tarball, you can also work directly from the meta-intel git repository. For each BSP in the 'meta-intel' repository, there are multiple branches, one corresponding to each major release starting with 'laverne' (0.90), in addition to the latest code which tracks the current master (note that not all BSPs are present in every release). Instead of extracting a BSP tarball at the top level of your yocto build tree, you can equivalently check out the appropriate branch from the meta-intel repository at the same location. b. Booting the intel-common BSP images -------------------------------------- If you've built your own image, either from the downloaded BSP layer or from the meta-intel git repository, you'll find the bootable image in the build/tmp/deploy/images/xxx directory, where again 'xxx' refers to the machine name used in the build. Under Linux, insert a USB flash drive. Assuming the USB flash drive takes device /dev/sdf, use dd to copy the image to it. Before the image can be burned onto a USB drive, it should be un-mounted. Some Linux distros may automatically mount a USB drive when it is plugged in. Using USB device /dev/sdf as an example, find all mounted partitions: $ mount | grep sdf and un-mount those that are mounted, for example: $ umount /dev/sdf1 $ umount /dev/sdf2 Now burn the image onto the USB drive: $ sudo dd if=core-image-sato-intel-corei7-64.wic of=/dev/sdf status=progress $ sync $ eject /dev/sdf This should give you a bootable USB flash device. Insert the device into a bootable USB socket on the target, and power on. This should result in a system booted to the Sato graphical desktop. If you want a terminal, use the arrows at the top of the UI to move to different pages of available applications, one of which is named 'Terminal'. Clicking that should give you a root terminal. If you want to ssh into the system, you can use the root terminal to ifconfig the IP address and use that to ssh in. The root password is empty, so to log in type 'root' for the user name and hit 'Enter' at the Password prompt: and you should be in. If you find you're getting corrupt images on the USB (it doesn't show the syslinux boot: prompt, or the boot: prompt contains strange characters), try doing this first: $ dd if=/dev/zero of=/dev/sdf bs=1M count=512 III. Technical Miscellany ========================= Benefits of using meta-intel ---------------------------- Using meta-intel has the following benefits over a generic BSP: tune flags ++++++++++ intel-* MACHINEs each have different compilation flags appropriate for their targeted hardware sets. intel-corei7-64 has tune flags appropriate for modern 64-bit Intel Core i microarchitecture, and includes instruction sets up to SSE4.2. intel-core2-32 has tune flags appropriate for legacy 32-bit Intel Core2 microarchitecture, and includes instruction sets up to SSE3. linux-intel kernel ++++++++++++++++++ The linux-intel kernel is an initiative to bring better Intel(R) hardware support to the current LTS linux kernel. It contains a base LTS kernel with additional backports from upstream Intel drivers. In addition, a default kernel config containing most features found on Intel boards is supplied via the yocto-kernel-cache. graphics stack ++++++++++++++ Meta-intel provides the latest Intel Graphics Linux Stack drivers to support Intel hardware as defined by the Other software ++++++++++++++ * intel ucode - provides the latest microcode updates for Intel processors * thermald - which proactively controls thermal, using P-states, T-states, and the Intel power clamp driver. ( The intel-common kernel package architecture -------------------------------------------- These BSPs use what we call the intel-common Linux kernel package architecture. This includes core2-32-intel-common and corei7-64-intel-common. These kernel packages can also be used by any of the BSPs in meta-intel that choose to include the file. To minimize the proliferation of vendor trees, reduce the sources we must support, and consolidate QA efforts, all BSP maintainers are encouraged to make use of the intel-common Linux kernel package architecture. Intel-specific machine features ------------------------------- The meta-intel layer makes some additional machine features available to BSPs. These machine features can be used in a BSP layer in the same way that machine features are used in other layers based on oe-core, via the MACHINE_FEATURES variable. Requirements ++++++++++++ The meta-intel-specific machine features are only available to a BSP when the meta-intel layer is included in the build configuration, and the file is included in the machine configuration of that BSP. To make these features available for your machine, you will need to: 1. include a configuration line such as the below in bblayers.conf BBLAYERS += "/meta-intel" 2. include the following line in the machine configuration file require conf/machine/include/ Once the above requirements are met, the machine features provided by the meta-intel layer will be available for the BSP to use. Available machine features ++++++++++++++++++++++++++ Currently, the meta-intel layer makes the following set of Intel-specific machine features available: * intel-ucode These machine features can be included by listing them in the MACHINE_FEATURES variable in the machine configuration file. For example: MACHINE_FEATURES += "intel-ucode" Machine feature details +++++++++++++++++++++++ * intel-ucode This feature provides support for microcode updates to Intel processors. The intel-ucode feature runs at early boot and uses the microcode data file added by the feature into the BSP's initrd. It also puts the userland microcode-updating tool, iucode_tool, into the target images along with the microcode data file. Q. Why might a user want to enable the intel-ucode feature? A. Intel releases microcode updates to correct processor behavior as documented in the respective processor specification updates. While the normal approach to getting such microcode updates is via a BIOS upgrade, this can be an administrative hassle and not always possible in the field. The intel-ucode feature enables the microcode update capability present in the Linux kernel. It provides an easy path for upgrading processor microcode without the need to change the BIOS. If the feature is enabled, it is also possible to update the existing target images with a newer microcode update in the future. Q. How would a user bundle only target-specific microcode in the target image? A. The Intel microcode data file released by Intel contains microcode updates for multiple processors. If the BSP image is meant to run on only a certain subset of processor types, a processor-specific subset of microcode can be bundled into the target image via the UCODE_FILTER_PARAMETERS variable. This works by listing a sequence of iucode-tool parameters in the UCODE_FILTER_PARAMETERS variable, which in this case will select only the specific microcode relevant to the BSP. For more information on the underlying parameters refer to the iucode-tool manual page at To define a set of parameters for microcode-filtering via the UCODE_FILTER_PARAMETERS variable, one needs to identify the cpuid signatures of all the processors the BSP is meant to run on. One way to determine the cpuid signature for a specific processor is to build and run an intel-ucode-feature-enabled image on the target hardware, without first assigning any value to the UCODE_FILTER_PARAMETERS variable, and then once the image is booted, run the "ucode_tool -S" command to have the ucode tool scan the system for processor signatures. These signatures can then be used in the UCODE_FILTER_PARAMETERS variable in conjunction with -s parameter. For example, for the fri2 BSP, the cpuid can be determined as such: [root@fri2 ~]# iucode_tool -S iucode_tool: system has processor(s) with signature 0x00020661 Given that output, a suitable UCODE_FILTER_PARAMETERS variable definition could be specified in the machine configuration as such: UCODE_FILTER_PARAMETERS = "-s 0x00020661" Q. Are there any reasons a user might want to disable the intel-ucode feature? A. The microcode data file and associated tools occupy a small amount of space (a few KB) on the target image. BSPs which are highly sensitive to target image size and which are not experiencing microcode-related issues might consider not enabling this feature. IV. Tested Hardware =================== The following undergo regular basic testing with their respective MACHINE types. Note that both 64-bit and 32-bit firmware is available for the MinnowBoard Turbot, so it is tested against both intel-corei7-64 and intel-core2-32. intel-corei7-64: NUC6i5SYH MinnowBoard Turbot intel-core2-32: MinnowBoard Turbot V. Guidelines for submitting patches ==================================== Please submit any patches against meta-intel BSPs to the meta-intel mailing list ( Also, if your patches are available via a public git repository, please also include a URL to the repo and branch containing your patches as that makes it easier for maintainers to grab and test your patches. There are patch submission scripts available that will, among other things, automatically include the repo URL and branch as mentioned. Please see the Yocto Project Development Manual sections entitled 'Using Scripts to Push a Change Upstream and Request a Pull' and 'Using Email to Submit a Patch' for details. Regardless of how you submit a patch or patchset, the patches should at minimum follow the suggestions outlined in the 'Submitting a Change to the Yocto Project' section in the Yocto Project Development Manual. Specifically, they should: - Include a 'Signed-off-by:' line. A commit can't legally be pulled in without this. - Provide a single-line, short summary of the change. This short description should be prefixed by the BSP or recipe name, as appropriate, followed by a colon. Capitalize the first character of the summary (following the colon). - For the body of the commit message, provide detailed information that describes what you changed, why you made the change, and the approach you used. - If the change addresses a specific bug or issue that is associated with a bug-tracking ID, include a reference to that ID in your detailed description in the following format: [YOCTO #]. - Pay attention to line length - please don't allow any particular line in the commit message to stretch past 72 characters. - For any non-trivial patch, provide information about how you tested the patch, and for any non-trivial or non-obvious testing setup, provide details of that setup. Doing a quick 'git log' in meta-intel will provide you with many examples of good example commits if you have questions about any aspect of the preferred format. The meta-intel maintainers will do their best to review and/or pull in a patch or patchset within 24 hours of the time it was posted. For larger and/or more involved patches and patchsets, the review process may take longer. Please see the meta-intel/MAINTAINERS file for the list of maintainers and their specific areas; it's also a good idea to cc: the specific maintainer, if applicable.