This tutorial details the basics of how to boot up a Freescale T4240QDS board and also explains how to build an image in yocto and boot it up on the board. The intended audience is an absolute beginner who is new to the yocto build and working on a board like T4240 Download the QorIQ SDK from freescale’s site. The SDK site can be found in: http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=SDKLINUX The version that is used in this documentation is version 1.4. Version 1.4 can be found in: http://www.freescale.com/webapp/sps/site/overview.jsp?code=QORIQSDK_1.4 The SDK has 3 important components, The source ISO – The actual SDK source that we are going to use. The cache state ISO – These files contain sstate-cache directory, i.e all packages pre-downloaded, this makes the build run faster. The image ISO – These are pre-built images for all Freescale targets. This is not required for this tutorial, since we are building our own images. The name of the source ISO that you are looking for is: QorIQ Linux SDK v1.4 Yocto Source ISO Once you click Source, go ahead and login when the site prompts. Download the source ISO, we are going to work on this. Open a terminal Create the iso directory qoriq@usernsl-Veriton-Series:~$ sudo mkdir /media/sourceiso Mount the iso. qoriq@usernsl-Veriton-Series:~$ sudo mount -o loop Downloads/QorIQ-SDK-V1.4-SOURCE-20130625-yocto.iso /media/sourceiso/ Change into source directory qoriq@usernsl-Veriton-Series:~$ cd /media/sourceiso/ Copy the source SDK qoriq@usernsl-Veriton-Series:/media/sourceiso$ sudo cp yocto.tar.gz ~/ Change into working directory qoriq@usernsl-Veriton-Series:/media/sourceiso$ cd Create the root SDK directory qoriq@usernsl-Veriton-Series:~$ mkdir yocto Move the gzip file into directory qoriq@usernsl-Veriton-Series:~$ mv yocto.tar.gz yocto/ Change into working directory qoriq@usernsl-Veriton-Series:~$ cd yocto/ Unzip the source qoriq@usernsl-Veriton-Series:~/yocto$ tar xvf yocto.tar.gz View the source files/directories qoriq@usernsl-Veriton-Series:~/yocto$ ls bitbake LICENSE meta-fsl-ppc meta-oe meta-yocto README sources documentation meta meta-fsl-ppc-toolchain meta-skeleton meta-yocto-bsp README.hardware yocto.tar.gz fsl-setup-poky meta-fsl-networking meta-hob meta-virtualization oe-init-build-env scripts Preparing the kernel Freescale kernel is configured in the layer ‘yocto/meta-fsl-ppc/recipes-kernel/linux’ folder. It containes recipes (.bb) files that tell the SDK how to download/configure/install the kernel. There are 2 portions to the kernel configuration, one is the kernel itself (linux-qoriq-sdk.bb file) and the kernel headers (linux-qoriq-sdk-headers.bb file). First we are going to show how to prepare the kernel to change the kernel sources within the kernel recipes. This can help us modify the sources. Move into home directory qoriq@usernsl-Veriton-Series:~/yocto$ cd .. Download the freescale kernel that is going to be built for the target qoriq@usernsl-Veriton-Series:~$ git clone git://git.freescale.com/ppc/sdk/linux.git Cloning into 'linux'... remote: Counting objects: 2931244, done. remote: Compressing objects: 100% (481548/481548), done. remote: Total 2931244 (delta 2449497), reused 2902973 (delta 2421384) Receiving objects: 100% (2931244/2931244), 581.84 MiB | 92 KiB/s, done. Resolving deltas: 100% (2449497/2449497), done. Rename the kernel tree to the Yocto compatible directory (this makes the build run error free, with minimal changes) qoriq@usernsl-Veriton-Series:~$ mv linux/ linux-qoriq-sdk Create a gzip file of the kernel source qoriq@usernsl-Veriton-Series:~$ tar zcvf linux-qoriq-sdk.tar.gz linux-qoriq-sdk/ Generate the md5sum of the kernel gzip, (used in the build conf file) qoriq@usernsl-Veriton-Series:~$ md5sum linux-qoriq-sdk.tar.gz 986feb8581d3521f295884270d7cc5f2 linux-qoriq-sdk.tar.gz Now the kernel is ready to be given as input to the build environment. The kernel sources (from where the kernel is downloaded/fetched) is, by default, the freescale git repository. Since we downloaded the kernel from the same repository we should remember to change the kernel sources to the gzip file that we created. We show how to do this, further in this tutorial. The Build proceedure These are the build commands to generate the images. Change into the yocto directory qoriq@usernsl-Veriton-Series:~ cd yocto Source the environment qoriq@usernsl-Veriton-Series:~/yocto$ source fsl-setup-poky -m Configuring for t4240qds board type Creating an yocto build output at /home/qoriq/yocto/ build_t4240qds_release Run the following commands to start a build: bitbake fsl-image-core bitbake fsl-image-lsb-sdk bitbake fsl-image-flash bitbake fsl-image-full bitbake fsl-image-kvm bitbake fsl-image-minimal To return to this build environment later please run: source /home/qoriq/yocto/build_t4240qds_release/SOURCE_THIS Sourcing the environment makes all the yocto commands(bitbake, runqemu, runqemu-extract-sdk, yocto-layer etc.) available, it also creates a default environment that can be configured to build for various different architectures and machines. The two important configuration files that need to be modified are: conf/local.conf conf/bblayers.conf We will see what these files contain and what we are going to modify. Open conf/local.conf qoriq@usernsl-Veriton-Series:~/yocto/build_t4240qds_release$ nano conf/local.conf Find the line that has : #BB_NUMBER_THREADS = "4" Uncomment the line and change it into BB_NUMBER_THREADS = "8" This creates 8 threads and does the build in parallel. Find the line that has: #PARALLEL_MAKE = "-j 4" Uncomment and change it into PARALLEL_MAKE = "-j 8" This variable is sent as parameter to all make invocation and performs the make in parallel with 8 threads Find the line that has: MACHINE ??= "qemux86" And replace with: MACHINE ??= "t4240qds" This variable determines the machine that the image is built for. “qemux86” is a x86 image that can be run virtually on the host system. “t4240qds” is the machine that we are building the images for. Hit Ctrl + X to exit Configuring kernel recipes Move to yocto folder qoriq@usernsl-Veriton-Series:~/yocto/build_t4240qds_release $ cd .. Change into the kernel recipe directory qoriq@usernsl-Veriton-Series:~/yocto$ cd meta-fsl-ppc/recipes-kernel/linux/ The directory contains a set of files. All .bb files are recipes and they contain configurations to fetch/configure/compile/install packages.All .inc files are include files, they are included within the corresponding .bb file with the “require “ command The files linux-qoriq-sdk.* are files that configure the kernel. The files linux-qoriq-sdk-headers.* are files that configure the header files for the kernel We need to separate the sources for the kernel and the headers and then configure the kernel sources to point to the kernel that we have already zipped and made available Make a copy of linux-qoriq-sdk.inc and keep it as linux-qoriq-sdk-headers.inc qoriq@usernsl-Veriton-Series:~/yocto/meta-fsl-ppc/recipes-kernel/linux$ cp linux-qoriq-sdk.inc linux-qoriq-sdk-headers.inc Open linux-qoriq-sdk-headers.inc qoriq@usernsl-Veriton-Series:~/yocto/meta-fsl-ppc/recipes-kernel/linux$ nano linux-qoriq-sdk-headers.bb Find the line that has: require recipes-kernel/linux/linux-qoriq-sdk.inc Edit it to: require recipes-kernel/linux/linux-qoriq-sdk-headers.inc We have separated the sources for the kernel and the headers, now we proceed to edit the sources of the kernel Open linux-qoriq-sdk.inc file qoriq@usernsl-Veriton-Series:~/yocto/meta-fsl-ppc/recipes-kernel/linux$ nano linux-qoriq-sdk.inc Edit the file to look like: ## File starts here ## LIC_FILES_CHKSUM = "file://COPYING;md5=d7810fab7487fb0aad327b76f1be7cd7" PV = "3.8" INC_PR = "r9" #SRCREV = "4b66366af2d77de68f4bd6548d07421e13d3df05" #SRC_URI = "git://git.freescale.com/ppc/sdk/linux.git \ # " SRC_URI = "file:///home/qoriq/linux-qoriq-sdk.tar.gz" SRC_URI[md5sum] = "986feb8581d3521f295884270d7cc5f2" KSRC ?= "" S = '${@base_conditional("KSRC", "", "${WORKDIR}/linux-qoriq-sdk", "${KSRC}", d)}' # make everything compatible for the time being COMPATIBLE_MACHINE_$MACHINE = "$MACHINE" python () { ma = d.getVar("DISTRO_FEATURES", True) arch = d.getVar("OVERRIDES", True) # the : after the arch is to skip the message on 64b if not "multiarch" in ma and ("e5500:" in arch or "e6500:" inarch): arch requires multiarch to be in DISTRO_FEATURES") promote_kernel = d.getVar('BUILD_64BIT_KERNEL') if promote_kernel == "1": raise bb.parse.SkipPackage("Building the kernel for this d.setVar('KERNEL_CC_append', ' -m64') d.setVar('KERNEL_LD_append', ' -melf64ppc') error_qa = d.getVar('ERROR_QA', True) if 'arch' in error_qa: d.setVar('ERROR_QA', error_qa.replace(' arch', '')) all_qa = d.getVar('ALL_QA', True) if 'arch' in all_qa: d.setVar('ALL_QA', all_qa.replace(' arch', '')) ## File ends here ## (( Note: It is adviceable to copy the entire contents above and replace with the contents of the file. If you are unable to copy the above source and have it properly aligned, follow the list of changes below and change it manually: Find the variable INC_PR and set it to INC_PR = “r9” Comment out the existing SRCREV and SRC_URI variable: SRCREV = "4b66366af2d77de68f4bd6548d07421e13d3df05" SRC_URI = "git://git.freescale.com/ppc/sdk/linux.git \ " And replace with the sources you had built SRC_URI = file:///home/qoriq/linux-qoriq-sdk.tar.gz SRC_URI[md5sum] = “986feb8581d3521f295884270d7cc5f2” Make sure the entered md5sum matches that of the kernel source available in that particular location. The build sets a variable S as: S = '${@base_conditional("KSRC", "", "${WORKDIR}/git", "${KSRC}", d)}' We need to modify it as: S = '${@base_conditional("KSRC", "", "${WORKDIR}/linux-qoriq-sdk", "${KSRC}", d)}' )) Building the image Now we are ready to run the build, After sourcing the environment, we find that the bitbake (build command) can generate various images: bitbake fsl-image-core bitbake fsl-image-lsb-sdk bitbake fsl-image-flash bitbake fsl-image-full bitbake fsl-image-kvm bitbake fsl-image-minimal These images provide various different functionality within the image, we are going to use the image: fsl-image-core as it can generate a bootable and minimal image with adequate functionality. The build can take a long time to run. Change to build directory qoriq@usernsl-Veriton-Series:~/yocto/meta-fsl-ppc/recipes-kernel/linux$ cd ~/yocto/build_t4240qds_release/ qoriq@usernsl-Veriton-Series:~/yocto/build_t4240qds_release$ bitbake fsl-image-core Loading cache: 100% |#################################################################################################| ETA: 00:00:00 Loaded 3120 entries from dependency cache. Build Configuration: BB_VERSION = "1.18.0" BUILD_SYS = "i686-linux" NATIVELSBSTRING = "Ubuntu-12.04" TARGET_SYS = "powerpc-fsl_networking-linux" MACHINE = "t4240qds" DISTRO = "fsl-networking" DISTRO_VERSION = "1.4" TUNE_FEATURES = "m32 fpu-hard e6500 altivec" TARGET_FPU = "hard" meta meta-yocto meta-yocto-bsp = "sdk-v1.4.x:5a7532143a49f59a5c85b08d3daf574fb1eccd8d" meta-fsl-ppc = "sdk-v1.4.x:f9fd0a617eb6913f87335c551918315ff4ebe18c" meta-fsl-ppc-toolchain = "sdk-v1.4.x:8ec94cec04527cb971c125b1ddd2c5375034d723" meta-virtualization = "sdk-v1.4.x:ad6df4f59cd7646f61db29e8fa51f878329d6f93" meta-fsl-networking = "(nobranch):00f7a535029ca7ef8c96ba8e9916d4742166bab0" meta-oe meta-networking = "sdk-v1.4.x:7c8dd8f096b64a709175d37a08a4fb02ca263616" NOTE: Resolving any missing task queue dependencies NOTE: Preparing runqueue NOTE: Executing SetScene Tasks NOTE: Executing RunQueue Tasks NOTE: Tasks Summary: Attempted 3164 tasks of which 3162 didn't need to be rerun and all succeeded. Create a temporary folder to extract the root filesystem qoriq@usernsl-Veriton-Series:~/yocto/build_t4240qds_release$ mkdir ~/rootfs Extract to the folder qoriq@usernsl-Veriton-Series:~/yocto/build_t4240qds_release$ runqemu-extract-sdk tmp/deploy/images/fsl-image-core-t4240qds-20140218104652.rootfs.tar.gz ../../rootfs (( Note: that the tar.gz file contains the root filesystem of the build and the timestamp in the filename may vary. But essentially the file that has to be extracted will be in the form: fsl-image-core-t4240qds-<timestamp>.rootfs.tar.gz )) Adding packages into the root filesystem Follow this set of instructions if you want to add a sample package into the root directory, else these can be skipped. There are multiple ways with which a package can be included, refer the yocto manual for a complete list of techniques. This tutorial gives an easy way to achieve this. In the yocto, main root directory we can find various directories like “meta-*” these directories contain recipes to include packages/kernels etc. These are called layers. To create a package we are going to create a new layer and within which we are going to create a recipe and thereby a .bb file that configures the package. The package that we are showing is the GNU package, htop. (( Note: This set of instructions depends on the packages that is being installed, but this works for mostly GNU-licensed packages )) Move to the home directory qoriq@usernsl-Veriton-Series:~/yocto/build_t4240qds_release $ cd Download the package qoriq@usernsl-Veriton-Series:~$ wget http://hisham.hm/htop/releases/1.0.2/htop-1.0.2.tar.gz --2014-02-24 14:14:40-- http://hisham.hm/htop/releases/1.0.2/htop-1.0.2.tar.gz Resolving hisham.hm (hisham.hm)... 69.163.170.116 Connecting to hisham.hm (hisham.hm)|69.163.170.116|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 388499 (379K) [application/x-tar] Saving to: `htop-1.0.2.tar.gz.1' 100%[======================================>] 3,88,499 169K/s in 2.2s 2014-02-24 14:14:44 (169 KB/s) - `htop-1.0.2.tar.gz.1' saved [388499/388499] Extract the package qoriq@usernsl-Veriton-Series:~$ tar xvf htop-1.0.2.tar.gz Check the md5sum of the package and make note of it qoriq@usernsl-Veriton-Series:~$ md5sum htop-1.0.2.tar.gz 0d01cca8df3349c74569cefebbd9919e htop-1.0.2.tar.gz Check the md5sum of the COPYING file (This is to check the license of the package) Change into the directory qoriq@usernsl-Veriton-Series:~$ cd htop-1.0.2/ Check the md5sum of the package and make note of it qoriq@usernsl-Veriton-Series:~/htop-1.0.2$ md5sum COPYING c312653532e8e669f30e5ec8bdc23be3 COPYING Yocto has a wide set of commands/scripts, yocto-layer is one such command that creates a layer. Initially we are going to create a new layer and within that layer we are going to create a recipe within the layer and the necessary .bb file to configure the package. Move into the yocto directory qoriq@usernsl-Veriton-Series:~$ cd yocto Create the layer qoriq@usernsl-Veriton-Series:~/yocto$ yocto-layer create mylayer Please enter the layer priority you'd like to use for the layer: [default: 6] <hit Enter> Would you like to have an example recipe created? (y/n) [default: n] <hit Enter> Would you like to have an example bbappend file created? (y/n) [default: n] <hit Enter> New layer created in meta-mylayer. qoriq@usernsl-Veriton-Series:~/yocto$ cd meta-mylayer/ Create the package directory qoriq@usernsl-Veriton-Series:~/yocto/meta-mylayer/hello$ mkdir htop Change into directory qoriq@usernsl-Veriton-Series:~/yocto/meta-mylayer/hello$ cd htop Create the config file qoriq@usernsl-Veriton-Series:~/yocto/meta-mylayer/htop$ nano htop_1.0.2.bb (( Note: Naming the .bb file depends on the version of the package that is being included,the format to follow is: <package-name>_<version number>.bb )) The contents of the bb file should be like: ## File starts here ## DESCRIPTION = "Htop performance monitor" SECTION = "performance monitor" LICENSE = "GPLv2+" LIC_FILES_CHKSUM = "file://COPYING;md5=c312653532e8e669f30e5ec8bdc23be3" PR = "r0" SRC_URI = "file:///home/qoriq/htop-1.0.2.tar.gz" SRC_URI[md5sum] = "0d01cca8df3349c74569cefebbd9919e" inherit autotools gettext ## File ends here ## Make sure you have entered the md5sum values that you have generated, and they match perfectly. Now the layer you have created should be added into the layers file conf/bblayers.conf This file includes all the layers (of packages, kernels and other configurations) into the build, since we created a new yocto layer we need to include it in this file. Change to build directory qoriq@usernsl-Veriton-Series:~/yocto/meta-mylayer/htop$ cd ../../build_t4240qds_release Open the bblayers file qoriq@usernsl-Veriton-Series:~/yocto/build_t4240qds_release$ nano conf/bblayers.conf Find the BBLAYERS variable: BBLAYERS ?= " \ /home/qoriq/yocto/meta \ /home/qoriq/yocto/meta-yocto \ /home/qoriq/yocto/meta-yocto-bsp \ /home/qoriq/yocto/meta-fsl-ppc \ /home/qoriq/yocto/meta-fsl-ppc-toolchain \ /home/qoriq/yocto/meta-virtualization \ /home/qoriq/yocto/meta-fsl-networking \ /home/qoriq/yocto/meta-oe/meta-oe \ /home/qoriq/yocto/meta-oe/meta-networking \ " Append the location of your layer in the end BBLAYERS ?= " \ /home/qoriq/yocto/meta \ /home/qoriq/yocto/meta-yocto \ /home/qoriq/yocto/meta-yocto-bsp \ /home/qoriq/yocto/meta-fsl-ppc \ /home/qoriq/yocto/meta-fsl-ppc-toolchain \ /home/qoriq/yocto/meta-virtualization \ /home/qoriq/yocto/meta-fsl-networking \ /home/qoriq/yocto/meta-oe/meta-oe \ /home/qoriq/yocto/meta-oe/meta-networking \ /home/qoriq/yocto/meta-mylayer \ " Save and proceed to build (as given above). SD card layout The SD card should contain a single ext2 partition which holds the uImage files and the root filesystem. Insert the SD card into the host machine, and using the mount command figure out the where it is mounted and the tag of the device. Format the disk qoriq@usernsl-Veriton-Series:~$ sudo fdisk /dev/sdc (( Note: The device ID of your SD card can be found out by running the mount command )) Delete all partitions Command (m for help): d Selected partition 1 Print the number of partitions (Hit p and then enter) Command (m for help): p Disk /dev/sdc: 3965 MB, 3965190144 bytes 4 heads, 12 sectors/track, 161344 cylinders, total 7744512 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x558eef06 Device Boot Start End Blocks Id System As expected the partition table shows empty Create new partition (Hit n and press Enter) Command (m for help): n Partition type: p primary (0 primary, 0 extended, 4 free) e extended Select (default p): <Hit Enter> Using default response p Partition number (1-4, default 1): <Hit Enter> Using default value 1 First sector (2048-7744511, default 2048): <Hit Enter> Using default value 2048 Last sector, +sectors or +size{K,M,G} (2048-7744511, default 7744511): Using default value 7744511 Print to see new partition (Hit p and then Enter) Command (m for help): p Disk /dev/sdc: 3965 MB, 3965190144 bytes 4 heads, 12 sectors/track, 161344 cylinders, total 7744512 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x558eef06 Device Boot Start End Blocks Id System /dev/sdc1 2048 7744511 3871232 83 Linux Write the changes and exit (Hit w and then Enter) Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. WARNING: Re-reading the partition table failed with error 16: Device or resource busy. The kernel still uses the old table. The new table will be used atthe next reboot or after you run partprobe(8) or kpartx(8) Syncing disks. Create the ext2 filesystem in the created partition qoriq@usernsl-Veriton-Series:~$ mkfs.ext2 /dev/sdc1 Copy the kernel image into the SD card qoriq@usernsl-Veriton-Series:~$ sudo cp -d yocto/build_t4240qds_release/tmp/deploy/images/uImage* /media/7e19cd10-3ed8-436d-956c-3fdb14c84e3d/ (( Note: The –d option is necessary, it preserves all symbolic links )) Change into the root directory qoriq@usernsl-Veriton-Series:~ $ cd rootfs Copy root filesystem into the SD card qoriq@usernsl-Veriton-Series:~/rootfs$ sudo cp -Rd * /media/7e19cd10-3ed8-436d-956c-3fdb14c84e3d/ Sync qoriq@usernsl-Veriton-Series:~/rootfs$ sync Unmount qoriq@usernsl-Veriton-Series:~/rootfs$ sudo umount /media/7e19cd10-3ed8-436d-956c-3fdb14c84e3d/ T4240QDS Booting Open the serial console with qoriq@usernsl-Veriton-Series:~ $ sudo gtkterm Open Configuration -> Port and set the Baudrate to 115200. Insert the SD card into the machine and power up. A u-boot prompt appears, hit Enter to disrupt automatic booting. Once you see the u-boot console, you’ll need to configure the environment variables Hit print to see all environment variables, mine look like: => print baudrate=115200 bdev=sda3 bootargs=root=/dev/mmcblk0p1 rw rootdelay=5 console=ttyS0,115200 bootcmd=setenv bootargs root=/dev/mmcblk0p1 rw rootdelay=5 console=$consoledev,$baudrate;mmcinfo;ext2load mmc 0:1 $loadaddr $bootfile;ext2load mmc 0:1 $fdtaddr $fdtfile; bootm $loadaddr - $fdtaddr bootdelay=10 bootfile=uImage c=ffe consoledev=ttyS0 ethact=FM1@DTSEC5 ethprime=FM1@DTSEC1 fdtaddr=0x17200000 fdtfile=uImage-t4240qds.dtb filesize=0x3df080 fman_ucode=0xeff40000 gatewayip=10.116.65.1 hwconfig=fsl_ddr:ctlr_intlv=3way_4KB,bank_intlv=auto;usb1:dr_mode=host,phy_type=utmi ipaddr=10.116.65.32 loadaddr=0x10000000 netdev=eth0 netmask=255.255.255.0 nfsboot=setenv bootargs root=/dev/nfs rw nfsroot=$serverip:$rootpath ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname:$netdev:off console=$consoledev,$baudrate $othbootargs;tftp $loadaddr $bootfile;tftp $fdtaddr $fdtfile;bootm $loadaddr - $fdtaddr ramboot=setenv bootargs root=/dev/ram rw console=$consoledev,$baudrate $othbootargs;tftp $ramdiskaddr $ramdiskfile;tftp $loadaddr $bootfile;tftp $fdtaddr $fdtfile;bootm $loadaddr $ramdiskaddr $fdtaddr ramdiskaddr=0x02000000 ramdiskfile=t4240qds/ramdisk.uboot rootpath=/opt/nfsroot serverip=10.116.65.38 stderr=serial stdin=serial stdout=serial tftpflash=tftpboot $loadaddr $uboot && protect off $ubootaddr+$filesize && erase $ubootaddr +$filesize && cp.b $loadaddr $ubootaddr $filesize && protect on $ubootaddr +$filesize && cmp.b $loadaddr $ubootaddr $filesize uboot="u-boot.bin" ubootaddr=0xeff80000 Environment size: 1564/8188 bytes There are a few variables that you need to modify, and they are: $bootfile – file that is used as a kernel to boot $fdtfile – the device tree file specific to the T4240 from the yocto build $loadaddr – The temporary RAM address to which the kernel is loaded temporarily before being loadedinto the working memory space $fdtaddr – The temporary RAM address to which the device tree is loaded temporarily $bootargs – The boot argument that sets the root parameter to denote where the root filesystem is to be looked for and other variables such as baudrate etc. The values that I set are specific to the files I built, but other variables are common. The $loadaddr should hold a value 0x10000000 The $fdtaddr should hold a value 0x17200000 To set the values : => editenv boot file edit: uImage => editenv fdtfile edit: uImage-t4240qds.dtb => editenv loadaddr edit: 0x10000000 => editenv fdtaddr edit: 0x17200000 => savenenv Now go ahead and boot the machine, with: => setenv bootargs root=/dev/mmcblk0p1 rw rootdelay=5 console=$consoledev,$baudrate;mmcinfo;ext2load mmc 0:1 $loadaddr $bootfile;ext2load mmc 0:1 $fdtaddr $fdtfile; bootm $loadaddr - $fdtaddr (( Note: Break down of the above command: => setenv bootargs root=/dev/mmcblk0p1 rw rootdelay=5 console=$consoledev,$baudrate The previous command sets the location of the root filesystem, in this case, it is the MMC card, /dev/mmcblk0p1 => mmcinfo The above command prints out the details of the MMC card => ext2load mmc 0:1 $loadaddr $bootfile The above command reads the kernel image from the filesystem to the temporary RAM address for the machine to boot => ext2load mmc 0:1 $fdtaddr $fdtfile; The above command reads the fdtfile into RAM memory => bootm $loadaddr - $fdtaddr The above command issues the boot command with kernel addresses and fdt address as inputs )) Here the “root=” variable sets the device ID of the root filesystem and ext2load reads a file from an ext2 filesystem.The boot proceeds and then you see a login prompt with… INIT: Entering runlevel: 5 Starting Dropbear SSH server: dropbear. Starting network benchmark server: netserver. Starting system log daemon...0 Starting kernel log daemon...0 Stopping Bootlog daemon: bootlogd. Poky 9.0 (Yocto Project 1.4 Reference Distro) 1.4 t4240qds ttyS0 t4240qds login: Go ahead and login! t4240qds login: root root@t4240qds:~# You can verify that the build works with root@t4240qds:~# uname -a Linux t4240qds 3.8.13-rt9-QorIQ-SDK-V1.4 #1 SMP Tue Feb 18 12:26:03 IST 2014 ppc64 GNU/Linux The build date shows the date the image was built! If you have included the htop GNU package into the root filesystem, you can test it out. root@t4240qds:~# htop This opens the htop application!!
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