我正在尝试使用自己的U-Boot构建来在Jetson TK1板上启动
Linux.当我们推动验证启动时,我使用平面图像树(统一内核映像,设备树blob,…)来描述我的系统. U-Boot可以加载ITB文件并尝试启动内核,但系统会在此消息后挂起.
我假设这是因为没有引导参数传递给内核(原始启动添加了参数的加载)但我对如何将参数传递给内核有点傻眼.我尝试设置bootargs环境变量,但这并没有改变这种情况.
使用ITB文件时如何将内核参数传递给内核？
命令行参数(取自示例extlinux.conf的APPEND命令)：
console=ttyS0,115200n8 console=tty1 no_console_suspend=1 lp0_vec=2064@0xf46ff000 video=tegrafb mem=1862M@2048M memtype=255 ddr_die=2048M@2048M section=256M pmuboard=0x0177:0x0000:0x02:0x43:0x00 vpr=151M@3945M tsec=32M@3913M otf_key=c75e5bb91eb3bd947560357b64422f85 usbcore.old_scheme_first=1 core_edp_mv=1150 core_edp_ma=4000 tegraid=40.1.1.0.0 debug_uartport=lsport,3 power_supply=Adapter audio_codec=rt5640 modem_id=0 android.kerneltype=normal usb_port_owner_info=0 fbcon=map:1 commchip_id=0 usb_port_owner_info=0 lane_owner_info=6 emc_max_dvfs=0 touch_id=0@0 tegra_fbmem=32899072@0xad012000 board_info=0x0177:0x0000:0x02:0x43:0x00 root=/dev/mmcblk0p1 rw rootwait tegraboot=sdmmc gpt
/dts-v1/;
/ {
description = "Simple image with single Linux kernel and FDT blob";
#address-cells = <1>;
images {
kernel@1 {
description = "Vanilla Linux kernel";
data = /incbin/("./zImage");
type = "kernel";
arch = "arm";
os = "linux";
compression = "none";
load = <0x81008000>;
entry = <0x81008000>;
hash@1 {
algo = "crc32";
};
hash@2 {
algo = "sha1";
};
};
fdt@1 {
description = "Flattened Device Tree blob";
data = /incbin/("./tegra124-pm375.dtb");
type = "flat_dt";
arch = "arm";
compression = "none";
hash@1 {
algo = "crc32";
};
hash@2 {
algo = "sha1";
};
};
};
configurations {
default = "conf@1";
conf@1 {
description = "Boot Linux kernel with FDT blob";
kernel = "kernel@1";
fdt = "fdt@1";
};
};
};
U-Boot输出：
Tegra124 (Jetson TK1) # fatload mmc 1 0x90000000 /kernel_fdt.itb
reading /kernel_fdt.itb
5946200 bytes read in 497 ms (11.4 MiB/s)
Tegra124 (Jetson TK1) # bootm 0x90000000
## Loading kernel from FIT Image at 90000000 ...
Using 'conf@1' configuration
Verifying Hash Integrity ... OK
Trying 'kernel@1' kernel subimage
Description: Vanilla Linux kernel
Type: Kernel Image
Compression: uncompressed
Data Start: 0x900000ec
Data Size: 5910168 Bytes = 5.6 MiB
Architecture: ARM
OS: Linux
Load Address: 0x00000000
Entry Point: 0x00000000
Hash algo: crc32
Hash value: c5b4b377
Hash algo: sha1
Hash value: f001007efe83f563425bfe0659186a32395c946c
Verifying Hash Integrity ... crc32+ sha1+ OK
## Loading fdt from FIT Image at 90000000 ...
Using 'conf@1' configuration
Trying 'fdt@1' fdt subimage
Description: Flattened Device Tree blob
Type: Flat Device Tree
Compression: uncompressed
Data Start: 0x905a30ac
Data Size: 34678 Bytes = 33.9 KiB
Architecture: ARM
Hash algo: crc32
Hash value: e466b23e
Hash algo: sha1
Hash value: ec909ae16e62233d0ed1e1f4c909085abc9b5879
Verifying Hash Integrity ... crc32+ sha1+ OK
Booting using the fdt blob at 0x905a30ac
Loading Kernel Image ... OK
Using Device Tree in place at 905a30ac,end 905ae821
Starting kernel ...
解决方法
突出的问题是U-Boot输出文本后系统似乎挂起
Starting kernel ...
如果已加载未压缩的内核映像文件,则接下来将执行实际的内核启动代码.
但是如果加载了uImage或zImage文件(由于它们是自解压缩的,它们也被报告为“未压缩”),则执行的下一个代码将是附加到zImage文件的解压缩例程.通常,此解压缩例程将输出诸如的文本
Uncompressing Linux............ done,booting the kernel.
在执行实际的内核启动代码之前,在内核命令行的任何处理之前,在任何处理Device Tree blob之前,以及在从内核输出任何控制台之前(包括earlyprintk).
Load Address: 0x00000000 Entry Point: 0x00000000
与DT中指定的内容相比：
load = <0x81008000>;
entry = <0x81008000>;
由于内核映像是临时加载的
## Loading kernel from FIT Image at 90000000 ...
DT中的地址似乎是正确的,图像标题中的地址是假的.
假设在0x00000000处没有物理RAM,结果将是内核映像被复制(或解压缩)到虚假加载地址0,然后内核映像将通过分支到伪造入口点0来执行. cpu可能会挂起尝试从不存在的内存中执行垃圾,这与您报告的内容完全相关.
解决方法是(1)确认内核链接到正确的地址,(2)使用-a和-e命令选项在mkimage命令中指定正确的地址.这种修正至少应该让你超越这一点.
