Yocto学习笔记

1. 指定SRCREV的例子

#kernel-module-m8887-wlan.bb
DESCRIPTION = "Marvell M8887 Wifi kernel module"

require include/rcar-gen3-modules-common.inc

LICENSE = "GPLv2 & MIT"
LIC_FILES_CHKSUM = " \
    file://m8887/wlan/gpl-2.0.txt;md5=ab04ac0f249af12befccb94447c08b77 \
"

inherit module
DEPENDS = "linux-renesas"
PV = "15.44"
PR = "r4"

MARVELL_M8887_URL = "git://xxx/wireless.git"
BRANCH = "master"
BRANCH_board1 = "board1/master"
BRANCH_board2 = "board2/master"

# 若使用SRCREV=${AUTOREV} 使用AUTOREV不能编译旧版本的软件! （也就是checkout回去后，${AUTOREV}还是目前最新版的软件！）
# 使用externalsrc来直接编译源码目录下的代码，也可以不用每次都烦着更改SRCREV的值
SRCREV = "57341238a98b2752546b4de461f442dc4161f578"        

SRC_URI += "${MARVELL_M8887_URL};protocol=ssh;branch=${BRANCH}"

S = "${WORKDIR}/git"
WLAN_SRCDIR = "${S}/m8887/wlan"

module_do_compile() {
    # make marvell build-sys happy
    cd ${WLAN_SRCDIR}
    make
}

module_do_install() {
    install -d ${D}/lib/modules/${KERNEL_VERSION}/extra/
    install -d ${D}/etc/modprobe.d/
    install -m  ${WLAN_SRCDIR}/wlan.conf ${D}/etc/modprobe.d/wlan.conf
    install -m  ${WLAN_SRCDIR}/mlan.ko ${D}/lib/modules/${KERNEL_VERSION}/extra/
    install -m  ${WLAN_SRCDIR}/sd8xxx.ko ${D}/lib/modules/${KERNEL_VERSION}/extra/
}

PACKAGES += "kernel-module-mlan kernel-module-sd8xxx"

RDEPENDS_kernel-module-mlan_append = " marvell-m8887-fw-cal"
RDEPENDS_kernel-module-sd8xxx_append = " marvell-m8887-fw-cal"

FILES_${PN} += "\
    /etc/modprobe.d/ \
"

2. 使用externalsrc时刻编译最新代码，又不会影响编译旧版本软件

inherit externalsrc

# a dummy local SRC_URI entry, it is used to cheat kernel.class to prepare
# STAGING_KERNEL_DIR so building out-of-tree kernel module runs smoothly
SRC_URI_append = " file://foo"

EXTERNALSRC = "${TOPDIR}/../source_code/linux"
EXTERNALSRC_BUILD = "${WORKDIR}/build"

3.externalsrc编译软件来避免bb文件时刻由于git hash值与源文件保持同步

SUMMARY = "Marvell M8887 BT Kernel module"

require include/rcar-gen3-modules-common.inc

LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f402"

inherit module externalsrc
DEPENDS = "linux-renesas"
PV = "15.44"
PR = "r4"

EXTERNALSRC = "${TOPDIR}/../source/wireless/m8887/muart_bt" #这个就是S目录
EXTERNALSRC_BUILD = "${WORKDIR}/build"                        #这个就是B目录，编译时(run.compile中)首先cd到这个目录下然后进行编译！

EXTRA_OEMAKE += "BOARD=${MACHINE}"

do_compile() {
    cp -r ${B}/* ${WORKDIR}/build/    # 也可以写成 cp -r $(S)/* $(B)
    module_do_compile
}

do_install() {
    install -d ${D}/lib/modules/${KERNEL_VERSION}/extra/    #D目录是文件系统的根目录
    install -m 644 ${B}/hci_uart.ko ${D}/lib/modules/${KERNEL_VERSION}/extra/
}

4.bb文件中的EXTRA_OEMAKE = "BOARD_NAME=g8s" 会以宏BOARD=g8s的方式传给Makefile

5.有时bitbake时报elf文件"No GNU Hash",使用下面忽略 INSANE_SKIP_${PN} = "ldflags" INSANE_SKIP_${PN}-dev = "ldflags"

6.kernel-module-m8887-bt/15.44-r4/temp/run.do_compile(使用file看是个shell脚本)里面导出了各种变量且写明了编译方法。 (1)可以在bb文件中重写module_do_compile()，可以修改其O指定的路径 module_do_compile() {  oe_runmake xxxx O=PATH1 } (2)复写do_compile函数 do_compile() {     cp -r ${S}/* ${B}/     module_do_compile } bb文件中可以复写run.do_compile中的函数

7.run.do_configure  run.do_install run.do_package 这些文件在写bb文件时也可以参考。