Yocto tests

About

• All of the described things happen in Kubuntu 13.04
• Building Linux images for Zynq platform - ARMv7

Output targets

These names are as they appear in the u-boot configuration header file:

• boot.bin - u-boot as the first stage bootloader
• devicetree.dtb - device tree with described interfaces, zynq registers, interrupts and drivers
• uImage - kernel, drivers
• uramdisk.image.gz - applications

GIT

git clone -b dylan git://git.yoctoproject.org/poky.git
cd poky (just for convenience)
git clone -b dylan https://github.com/Xilinx/meta-xilinx.git meta-xilinx
git clone git://git.code.sf.net/p/elphel/meta-elphel393 meta-elphel393
git clone git://git.code.sf.net/p/elphel/meta-ezynq meta-ezynq
git clone -b dylan https://github.com/openembedded/meta-oe.git

Configure

• Step 1: Init environment

cd poky
. ./oe-init-build-env

• Step 2: Edit build/conf/bblayers.conf - add paths to BBLAYERS:

<absolute-path>/meta-xilinx \
<absolute-path>/meta-xilinx/meta-zedboard \
<absolute-path>/meta-elphel393 \
<absolute-path>/meta-ezynq \

• Step 3: Edit build/conf/local.conf - set MACHINE and other things:

 BB_NUMBER_THREADS = "8" (depends on the PC's CPU)
 PARALLEL_MAKE = "-j 8" (depends on the PC's CPU)
 MACHINE ?= "elphel393"

Notes

• Based on MACHINE="zedboard"
• Does ./oe-init-build-env scan all the meta-* dirs in poky? Unlikely.

Build ezynq-u-boot

bitbake ezynq-u-boot

Output

• boot.bin

Notes

• Is there a way to build it by running bitbake elphel393 (elphel393 is the name of the ramdisk image - currently coinsides with the name of MACHINE)

Build kernel

bitbake linux-xlnx

Output

• uImage (kernel)
• devicetree.dtb (or some *.dtb)

Notes

• The dtc script for converting device tree between *.dts and *.dtb formats is built along with the kernel.
• When linux-xlnx is 'clean' it is built with the ramdisk.image.gz by bitbake elphel393, however the boot.bin does not.

Build ramdisk.image.gz

bitbake elphel393

Output

• uramdisk.image.gz (the file has *.u-boot extension after it's built)

Notes

• Current packages:

elphel393.bb:
IMAGE_INSTALL = "packagegroup-core-boot python-core ${ROOTFS_PKGMANAGE_BOOTSTRAP} ${CORE_IMAGE_EXTRA_INSTALL}"

• Also works:

elphel393.bb:
IMAGE_INSTALL = "packagegroup-core-boot ${ROOTFS_PKGMANAGE_BOOTSTRAP} ${CORE_IMAGE_EXTRA_INSTALL}"
IMAGE_INSTALL_append = "python-core"

• Why python-core and not just python?
  • poky/meta/recipes-devtools/python/python-2.7-manifest.inc has a list in PACKAGES items from which should go into IMAGE_INSTALL
  • Among all there's no python in the PACKAGES list.
  • Does hob install all the PACKAGES if python is checked? Haven't tried, also the used hob version doesn't support saving recipes.
• (Is there a better solution? for kubuntu 13.04, in kubuntu 12.10 there were no such errors - or was it just newer version?) Adding packages : apache2, php, i2c-tools, mtd-utils, net-tools,openssh steps:
  • Clone meta-oe from OpenEmbedded:

git clone -b dylan https://github.com/openembedded/meta-oe.git

• • Lines to bblayers.conf:

   <absolute-path>/meta-oe/meta-oe \
   <absolute-path>/poky/meta-oe/meta-perl \
   <absolute-path>/poky/meta-oe/meta-webserver \

• • elphel393.bb (some discussions mention the leading space is mandatory but somehow it works even without it):

IMAGE_INSTALL_append = "<mandatory space?>python-core \
                       i2c-tools \
                       mtd-utils \
                       net-tools \
                       openssh \
                       modphp \
                       apache2 \
                       php-cli"

• • Why php-cli and not just php?

meta-oe/meta-oe/recipes-devtools/php/php.inc:
PACKAGES = "${PN}-dbg ${PN}-cli ${PN}-cgi ${PN}-fpm ${PN}-fpm-apache2 ${PN}-pear ${PN}-dev ${PN}-staticdev ${PN}-doc ${PN}"

• • • PACKAGES includes php. What is installed? (No php-cli: missing /usr/bin/php) Didn't investigate.
    • What does hob build if php is checked? Didn't test.
    • Using php-cli installs php in the /usr/bin/. Tested.
    • Using php-cli increases the unpacked image size from ~16MB to ~50MB.
  • To fix the ERROR="Could not inherit file classes/vala.bbclass" in bitbake copy vala.bbclass from oe-core? or delete the conflicting recipes (2?)?
  • To fix the ERROR="Failed to parse krb5_1.11.3.bb" in bitbake delete the directory meta-oe/meta-oe/recipes-connectivity/krb5

U-boot and device tree related notes

• The default UNPACKED ramdisk max size for zynq is 16MB - once it gets bigger you get KERNEL PANIC - the solution is modifying the device tree - then recompile into DTB:

*.dts, add to bootargs parameter ramdisk_size=32768 (takes KB), example:
bootargs = "console=ttyPS0,115200 root=/dev/ram rw ip=192.168.1.10 earlyprintk ramdisk_size=32768";

• The default COMPRESSED ramdisk max size for zynq is 10MB set in u-boot - change according to your needs, example:

zynq_zed.h:
"sdboot=echo Copying Linux from SD to RAM... && " \
               "mmcinfo && " \
               "fatload mmc 0 0x3000000 ${kernel_image} && " \
               "fatload mmc 0 0x2A00000 ${devicetree_image} && " \
               "fatload mmc 0 0x2000000 ${ramdisk_image} && " \
               "bootm 0x3000000 0x2000000 0x2A00000\0" \

So, the max sizes:
compressed ramdisk    = 0x2A00000 - 0x2000000 = 0xA00000 = 10MB
devicetree = 0x3000000 - 0x2A00000 = 0x600000 = 6MB

Build toolchain (not necessary)

• Step 1: build

bitbake meta-toolchain

• Step 2: install - launch installer from <some-path>/poky/build/tmp/deploy/