This page is intended to be a collection place for tips and tricks related to Yocto layers and how Yocto works under Petalinux.

Documentation

The first place you should start to better understand many details of the Yocto project is the Yocto project website.

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Create a fsbl bbappend file and add below content

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$ vim <plnx-proj-root>/project-spec/meta-user/recipes-bsp/fsbl/fsbl_%.bbappend
# From 2021.1 onwards
$ vim <plnx-proj-root>/project-spec/meta-user/recipes-bsp/embeddedsw/fsbl-firmware_%.bbappend

To enable debugs in FSBL:

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#Add debug for FSBL
XSCTH_BUILD_DEBUG = "1"

To add compiler flags in FSBL:

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#Add compiler flags for FSBL
YAML_COMPILER_FLAGS_append = " -DFSBL_PROT_BYPASS"

To add BSP flags(secure mode) in FSBL:

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#Add BSP flags for FSBL
YAML_BSP_CONFIG += "secure_mode"
YAML_BSP_CONFIG[secure_mode] = "set,true"

Create a pmu-firmware_%.bbappend file and add below content

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$ vim <plnx-proj-root>/project-spec/meta-user/recipes-bsp/pmu/pmu-firmware_%.bbappend

#For v2018.1 or later PetaLinux releases only
$ vim <plnx-proj-root>/project-spec/meta-user/recipes-bsp/pmu-firmware/pmu-firmware_%.bbappend

To enable debugs in PMUFW refer this https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18841724/PMU+Firmware page for DEBUG flags list

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#Add debug for PMUFW
XSCTH_BUILD_DEBUG = "1"

To add compiler flags in PMUFW, see PMU FW Build Flags:

Info
Note that the method of loading the PMUFW can prevent early prints (during code initialization) from being output. See PMU Firmware > Using FSBL to load PMUFW for additional details.

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#Add compiler flags for PMUFW
YAML_COMPILER_FLAGS_append = " -DDEBUG_MODE -DXPFW_DEBUG_DETAILED"

To add BSP flags(secure mode) in PMUFW:

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theme	Midnight

#Add BSP flags for PMUFW
YAML_BSP_CONFIG += "secure_mode"
YAML_BSP_CONFIG[secure_mode] = "set,true"

To add BSP flags(debug mode) in PMUFW: For example if you want to enable https://github.com/Xilinx/embeddedsw/blob/release-2018.3/lib/sw_apps/zynqmp_pmufw/misc/xfpga_config.h#L34 debug is Xil BSP libraries

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#Add BSP flags for PMUFW
YAML_BSP_CONFIG += "debug_mode"
YAML_BSP_CONFIG[debug_mode] = "set,true"

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1. Create a library using petalinux tools

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$ petlainux-create -t apps --template c --name sampleapp --enable

2. Modify the sampleapp.bb recipe file <plnx-proj-root>/project-spec/meta-user/recipes-apps/sampleapp/sampleapp.bb as

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#
# This file is the sampleapp recipe.
#
 
SUMMARY = "Simple sampleapp application"
SECTION = "PETALINUX/apps"
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"
 
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
 
SRC_URI = " \
          file://sampleapp.c \
         "
 
S = "${WORKDIR}"
 
DEPENDS += " libsample"
 
#This uses libsample.so.1.0.1 (-lsample)
do_compile() {
    ${CC} ${CFLAGS} ${LDFLAGS} -o sampleapp sampleapp.c -lsample
}
 
do_install() {
    install -d ${D}${bindir}
    install -d -m 0755 sampleapp ${D}${bindir}
}
 
FILES_${PN} += "sampleapp"

3. Modify the <plnx-proj-root>/project-spec/meta-user/recipes-apps/libsample/files/sampleapp.c generated from petalinux tools as

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#include <stdio.h>
#include <SAMPLE/sample.h>  // From above libs <TARGET_ROOTFS>/usr/lib/SAMPLE/sample.h
 
int main(int argc, char **argv)
{
    printf("Hello World!\n");
    sample_hello();
    return 0;
}

4. Build the apps recipe

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$ petalinux-build -c sampleapp

How to Auto Run Application at Startup

1. Create a library using petalinux tools

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$ petalinux-create -t apps --template install -n myapp-init --enable

2. Edit the file <plnx-proj-root>/project-spec/meta-user/recipes-apps/myapp-init/myappinit.bb. The file should look like the following:

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#this file is the myapp-init recipe.
#

SUMMARY = "Simple myapp-init application"
SECTION = "PETALINUX/apps"
LICENSE = "MIT"

LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"

SRC_URI = "file://myapp-init \
"

S = "${WORKDIR}"
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"

inherit update-rc.d
INITSCRIPT_NAME = "myapp-init"
INITSCRIPT_PARAMS = "start 99 S ."

do_install() {
	install -d ${D}${sysconfdir}/init.d
	install -m 0755 ${S}/myapp-init1init ${D}${sysconfdir}/init.d/myapp-init1init
}
FILES_${PN} += "${sysconfdir}/*"

3. To run myapp as daemon, edit the file <plnx-proj-root>/project-spec/meta-user/recipes-apps/myapp-init/files/myapp-init.

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#!/bin/sh
DAEMON=/usr/bin/myapp-init
start ()
{
        echo " Starting myapp-init"
        start-stop-daemon -S -o --background -x $DAEMON
}
stop ()
{
        echo " Stoping myapp-init"
        start-stop-daemon -K -x $DAEMON
}
restart()
{
        stop
        start
}

[ -e $DAEMON ] || exit 1

        case "$1" in
                start)
                        start; ;;
                stop)
                        stop; ;;
                restart)
                        restart; ;;
                *)
                        echo "Usage: $0 {start|stop|restart}"
                        exit 1
        esac
exit $?

4. Build the project

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petalinux-build

How to Auto Mount SD card in Yocto Recipes

1. Create a base-files directory in meta-user layer as

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$ mkdir -p <plnx-proj-root>/project-spec/meta-user/recipes-core/base-files

2. Create a base-files_%.bbappend file and add below content

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$ vim <plnx-proj-root>/project-spec/meta-user/recipes-core/base-files/base-files_%.bbappend
 
#base-files_%.bbappend content
 
dirs755 += "/media/card"
 
do_install_append() {
    sed -i '/mmcblk0p1/s/^#//g' ${D}${sysconfdir}/fstab
}

3. Rebuild rootfs

Code Block

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$ petalinux-build

How to Configure a Second Ethernet Interface(eth1) to Get the IP Address from DHCP in Yocto Recipes

Method 1: Append auto eth1 to existing interfaces file

1. Create a init-ifupdown directory in meta-user layer as

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language	bash
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$ mkdir -p <plnx-proj-root>/project-spec/meta-user/recipes-core/init-ifupdown/

2. Create a init_ifupdown_%.bbappend file and add below content

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language	bash
theme	Midnight

$ vim <plnx-proj-root>/project-spec/meta-user/recipes-core/init-ifupdown/init-ifupdown_%.bbappend
 
# init-ifupdown_%.bbappend content
 
do_install_append() {
    sed -i '/iface eth0 inet dhcp/ a auto eth1' ${D}${sysconfdir}/network/interfaces
}

3. Rebuild rootfs

Code Block

language	bash
theme	Midnight

$ petalinux-build

Method 2: Use your own interfaces file

1. Create a init-ifupdown directory in meta-user layer as

Code Block

language	bash
theme	Midnight

$ mkdir -p <plnx-proj-root>/project-spec/meta-user/recipes-core/init-ifupdown/files

2. Create your own network interface file as show below

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language	bash
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$ vim <plnx-proj-root>/project-spec/meta-user/recipes-core/init-ifupdown/files/myinterfaces
 
# myinterfaces content
 
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
 
# The loopback interface
auto lo
iface lo inet loopback
 
# Wireless interfaces
iface wlan0 inet dhcp
    wireless_mode managed
    wireless_essid any
    wpa-driver wext
    wpa-conf /etc/wpa_supplicant.conf
 
iface atml0 inet dhcp
 
# Wired or wireless interfaces
auto eth0
iface eth0 inet dhcp
 
# Add auto config for eth1
auto eth1
iface eth1 inet dhcp
 
# Ethernet/RNDIS gadget (g_ether)
# ... or on host side, usbnet and random hwaddr
iface usb0 inet static
    address 192.168.7.2
    netmask 255.255.255.0
    network 192.168.7.0
    gateway 192.168.7.1
 
# Bluetooth networking
iface bnep0 inet dhcp

3. Create a init_ifupdown_%.bbappend file and add below content

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language	bash
theme	Midnight

$ vim <plnx-proj-root>/project-spec/meta-user/recipes-core/init-ifupdown/init-ifupdown_%.bbappend
 
# init-ifupdown_%.bbappend content
 
SRC_URI += " \
        file://myinterfaces \
        "
 
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
 
# Overwrite interface file with myinterface file in rootfs
do_install_append() {
     install -m 0644 ${WORKDIR}/myinterfaces ${D}${sysconfdir}/network/interfaces
}

4. Rebuild rootfs

Code Block

language	bash
theme	Midnight

$ petalinux-build

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Versions Compared

Old Version 33

New Version 34

Key

Table of Contents

Documentation

How to Auto Run Application at Startup

How to Auto Mount SD card in Yocto Recipes

How to Configure a Second Ethernet Interface(eth1) to Get the IP Address from DHCP in Yocto Recipes

Method 1: Append auto eth1 to existing interfaces file

Method 2: Use your own interfaces file

Page Comparison

Versions Compared

Old Version 33

New Version 34

Key

Table of Contents

Documentation

How to Auto Run Application at Startup

How to Auto Mount SD card in Yocto Recipes

How to Configure a Second Ethernet Interface(eth1) to Get the IP Address from DHCP in Yocto Recipes

Method 1: Append auto eth1 to existing interfaces file

Method 2: Use your own interfaces file