开发环境：win10 64位 + VMware12 + Ubuntu14.04 32位
工具链：linaro提供的gcc-linaro-6.1.1-2016.08-x86_64_arm-linux-gnueabi
要移植的kernel版本：linux-4.4
Tiny4412开发板硬件版本为：
底板： Tiny4412SDK 1312B
核心板：Tiny4412 - 1306
1、下载、解压内核
linux-4.4.tar.gz
2、配置
1）配置开发板类型及指定交叉编译链
diff --git a/arch/arm/boot/dts/exynos4412-tiny4412.dts b/arch/arm/boot/dts/exyno
index 4840bbd..048ae67 100644
--- a/arch/arm/boot/dts/exynos4412-tiny4412.dts
+++ b/arch/arm/boot/dts/exynos4412-tiny4412.dts
@@ -21,6 +21,7 @@ ESCOD
index 70dea02..42b0d63 100644
--- a/Makefile
+++ b/Makefile
@@ -248,8 +248,11 @@ SUBARCH := $(shell uname -m | sed -e s/i.86/x86/ -e s/x86_6
# "make" in the configured kernel build directory always uses that.
# Default value for CROSS_COMPILE is not to prefix executables
# Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
-ARCH ?= $(SUBARCH)
-CROSS_COMPILE ?= $(CONFIG_CROSS_COMPILE:"%"=%)
+#ARCH ?= $(SUBARCH)
+#CROSS_COMPILE ?= $(CONFIG_CROSS_COMPILE:"%"=%)
+
+ARCH ?= arm
+CROSS_COMPILE ?= /usr/local/ARM-toolchian/gcc-linaro-6.1.1-2016.08-i686_arm-linux-gnueabi/bin/arm-linux-gnueabi- # Architecture as present in compile.h
UTS_MACHINE := $(ARCH)
2）修改设备树
diff --git a/arch/arm/boot/dts/exynos4412-tiny4412.dts b/arch/arm/boot/dts/exyno
index 4840bbd..048ae67
--- a/arch/arm/boot/dts/exynos4412-tiny4412.dts
+++ b/arch/arm/boot/dts/exynos4412-tiny4412.dts
@@ -, +, @@ chosen {
stdout-path = &serial_0;
+ bootargs="root=/dev/ram0 rw rootfstype=ext4 console=ttySAC0,115200 init=/linuxrc earlyprintk";
};
memory {
@@ -, +, @@
bus-width = <>;
pinctrl- = <&sd2_clk &sd2_cmd &sd2_cd &sd2_bus4>;
pinctrl-names = "default";
- status = "okay";
+ /* status = "okay";*/
+ status = "disabled";
};
&serial_0 {
这里关键的一点是在chosen中增加了bootargs的设置，上面设置bootargs表示的意思是：根文件系统是ramdisk，可读写，文件系统类型是ext4格式，串口终端使用ttySAC0，波特率是115200，earlyprintk用于打印内核启动早期的一些log，它会把printk的信息打印到一个叫做bootconsole的终端上，在真正的console注册后，bootconsole会被disable掉，要想使用earlyprintk，需要在内核中做相关的配置，这个下面再说。bootargs的设置很灵活，既可以在内核的设备树中设置，也可以在u-boot中设置，需要注意的是：如果在u-boot中设置了bootargs的话，在bootm的时候u-boot会用自己的bootargs来覆盖设备树里的bootargs( do_bootm_linux -> bootm_linux_fdt -> fdt_chosen)。还有一点是把SD卡控制器2给禁掉了，目前SD控制器的初始化还有些问题，会导致内核挂掉，这个以后再解决，因为我们将来先用ramdisk做根文件系统，跟eMMC和SD卡都没有关系
3,配置内核支持Ramdisk
make menuconfig
File systems --->;
<*> Second extended fs support
Device Drivers
SCSI device support --->;
<*> SCSI disk support
Block devices --->;
<*>RAM block device support
(16)Default number of RAM disks
(8192) Default RAM disk size (kbytes) (修改为8M)
General setup --->;
[*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
这个exynos的默认配置就已经支持了。
4.配置内核支持Tmpfs
$ make menuconfig File systems --->;
Pseudo filesystems --->
[*] Virtual memory file system support (former shm fs)
[*] Tmpfs POSIX Access Control Lists
这个exynos的默认配置也已经支持了。
5.编译内核
第一次编译需要获取exynos配置
make exynos_defconfig
root@ubuntu:/home/arm/linux-4.4# cat build.sh
#!/bin/bash echo "---------------"
echo "rm ./ uImage and dtb"
rm uImage exynos4412-tiny4412.dtb echo "make"
make uImage LOADADDR=0x40007000 -j4 echo "make dtb"
make dtbs echo "backup config"
cp .config tiny4412_defconfig echo "copy uImage"
cp arch/arm/boot/uImage ./ echo "copy dtb"
cp arch/arm/boot/dts/exynos4412-tiny4412.dtb ./ echo "over"
编写脚本。执行，烧写
即可初步启动kernel
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问题：启动后如果显示文件太多会出现
dma-pl330 12680000.pdma: Reset Channel-1 CS-20000f FTC-20000
[ 1573.447654] dma-pl330 12680000.pdma: Reset Channel-1 CS-20000f FTC-20000
参考：https://blog.****.net/sinat_20006769/article/details/79060779
说是DMA驱动的问题，按照介绍取消dma-pl330后，kernel无法启动
参考：https://blog.****.net/hyyoxhk/article/details/83305367
修改arch/arm/boot/dts/exynos4412-tiny4412.dts中，serial_0的dmas导致卡死，serial_2的dmas无效果
参考：https://blog.****.net/qq_25370227/article/details/84891632
是uboot中TrustZone造成，目前未尝试
--------------------------------------------------------------------------------------------------------------------------------------------------------------
已解决：就是TrustZone造成，具体查看：linux-kernel-4.4 移植 （2）解决上部遗留DMA-PL330的问题
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整体参考：
https://www.cnblogs.com/pengdonglin137/p/5143516.html
https://blog.****.net/sinat_20006769/column/info/19139