邮箱：zhuimengcanyang@163.com 痴爱嵌入式技术的蜗牛
分类： LINUX
2016-06-18 11:15:08
ARCH ?=
CROSS_COMPILE ?=
修改为：
ARCH ?= arm
CROSS_COMPILE ?= arm-linux-
tips:
vi中显示行号，在底行模式下输入：
:set nu // 即可以显示行号了
$ find -name "*defconfig"
可以看到一堆配置文件
......
......
./arch/arm/configs/ns9xxx_defconfig
./arch/arm/configs/iop32x_defconfig
./arch/arm/configs/realview-smp_defconfig
./arch/arm/configs/neponset_defconfig
./arch/arm/configs/at91sam9261ek_defconfig
./arch/arm/configs/lpd7a400_defconfig
./arch/arm/configs/h7201_defconfig
./arch/arm/configs/versatile_defconfig
./arch/arm/configs/kb9202_defconfig
./arch/arm/configs/at91sam9260ek_defconfig
./arch/arm/configs/fortunet_defconfig
./arch/arm/configs/ixp4xx_defconfig
./arch/arm/configs/picotux200_defconfig
./arch/arm/configs/at91sam9263ek_defconfig
./arch/arm/configs/mainstone_defconfig
./arch/arm/configs/clps7500_defconfig
./arch/arm/configs/at91rm9200dk_defconfig
./arch/arm/configs/pxa255-idp_defconfig
./arch/arm/configs/footbridge_defconfig
./arch/arm/configs/integrator_defconfig
./arch/arm/configs/csb637_defconfig
......
book@book-desktop:/work/system/llinux-3.4.2$ cd arch/arm/configs/
book@book-desktop:/work/system/linux-3.4.2/arch/arm/configs$ ls *2410*
s3c2410_defconfig
book@book-desktop:/work/system/linux-3.4.2$make s3c2410_defconfig
打印：表示配置为.config成功
......
#
# configuration written to .config
#
book@book-desktop:/work/system/linux-3.4.2$ make uImage
SMDK2410 # tftp 30000000 uImage_newkernel
SMDK2410 # bootm 30000000## Booting kernel from Legacy Image at 30000000 ...
分析u-boot启动内核流程：
在文件：\board\samsung\smdk2410\smdk2410.c 中可以找到默认的机器ID
u-boot-1.1.6中：
==========================
\common\md_bootm.c
do_bootm
boot_os[images.os.os]
do_bootm_linux
boot_jump_linux
unsigned long machid = gd->bd->bi_arch_number; // 获取默认的机器ID
s = getenv("machid"); // 从环境变量获取机器ID
r2 = gd->bd->bi_boot_params; // 获取bootload传递给kernel的参数
kernel_entry(0, machid, r2); // 启动内核，跳转到linux kernel的程序当中
==================================================================
u-boot-2012.04.01：做法都是一样的。
\common\cmd_bootm.c: do_bootz
U_BOOT_CMD(
bootz, CONFIG_SYS_MAXARGS, 1, do_bootz,
"boot Linux zImage image from memory",
"[addr [initrd[:size]] [fdt]]\n"
" - boot Linux zImage stored in memory\n"
"\tThe argument 'initrd' is optional and specifies the address\n"
"\tof the initrd in memory. The optional argument ':size' allows\n"
"\tspecifying the size of RAW initrd.\n"
);
static int do_bootz(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
do_bootm_linux(0, argc, argv, &images);
boot_jump_linux(images);
unsigned long machid = gd->bd->bi_arch_number; // 获取默认的机器ID
void (*kernel_entry)(int zero, int arch, uint params); // 构造函数
kernel_entry = (void (*)(int, int, uint))images->ep;
s = getenv("machid"); // 从环境参数获取机器ID
r2 = gd->bd->bi_boot_params; // 获取BootLoader传递参数给kernel的地址
kernel_entry(0, machid, r2); // 启动内核
board_init
gd->bd->bi_arch_number = MACH_TYPE_SMDK2410; // 默认的机器ID为：MACH_TYPE_SMDK2410 = 193
SMDK2410 # set machid 33245 //随便设置一个机器ID，启动内核
SMDK2410 # save
SMDK2410 # tftp 30000000 uImage_newkernel; bootm 30000000
启动会打印：
## Booting kernel from Legacy Image at 30000000 ...
Image Name: Linux-3.4.2
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 2399640 Bytes = 2.3 MiB
Load Address: 30108000
Entry Point: 30108000
Verifying Checksum ... OK
Loading Kernel Image ... OK
OK
Using machid 0x33245 from environment
Starting kernel ...
Uncompressing Linux... done, booting the kernel.
Error: unrecognized/unsupported machine ID (r1 = 0x00033245).
Available machine support:
ID (hex) NAME
00000400 AML_M5900
0000014b Simtec-BAST
0000015b IPAQ-H1940
0000039f Acer-N35
00000290 Acer-N30
000002a8 Nex Vision - Otom 1.1
00000454 QT2410
000000c1 SMDK2410
000005b4 TCT_HAMMER
000001db Thorcom-VR1000
000005d2 JIVE
000003fe SMDK2413
000003f1 SMDK2412
00000377 S3C2413
00000474 VSTMS
00000695 SMDK2416
000002de Simtec-Anubis
00000707 AT2440EVB
000007cf MINI2440
000002a9 NexVision - Nexcoder 2440
0000034a Simtec-OSIRIS
00000250 IPAQ-RX3715
0000016a SMDK2440
00000518 GTA02
000003b8 HP iPAQ RX1950
0000043c SMDK2443
Please check your kernel config and/or bootloader.
会打印这句话：Error: unrecognized/unsupported machine ID (r1 = 0x00033245).
说明环境变量输入的机器ID不认识/不支持。
如果想使用机器：SMDK2440，则机器ID设置成相应的值：0000016a
uboot中默认的机器ID设置为，传递给内核的也是这个机器ID。
000000c1 SMDK2410
SMDK2410 # set machid 16a
SMDK2410 # save
SMDK2410 # tftp 30000000 uImage_newkernel; bootm 30000000
打印：
## Booting kernel from Legacy Image at 30000000 ...
Image Name: Linux-3.4.2
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 2399640 Bytes = 2.3 MiB
Load Address: 30108000
Entry Point: 30108000
Verifying Checksum ... OK
Loading Kernel Image ... OK
OK
Using machid 0x16a from environment
Starting kernel ...
Uncompressing Linux... done, booting the kernel.
?x?x?x?x??x?x?x??x??x?xxxx???x?x?x?x?x?x??xxx?x??
乱码一堆.......
但是没有出现机器ID的错误。。。。。
SMDK2410 # set machid 7cf
SMDK2410 # save
SMDK2410 # tftp 30000000 uImage_newkernel; bootm 30000000
还是打印乱码，这说明不是机器ID的问题，可能是串口波特率或者时钟没配置正确。
SMDK2410 # print
baudrate=115200
bootargs=console=ttySAC0 root=/dev/nfs nfsroot=192.168.1.10:/work/nfs_root/first_fs ip=192.168.1.17:192.168.1.10:192.168.1.1:255.255.255.0::eth0:off
bootcmd=nand read 0x30000000 kernel; bootm 0x30000000
bootdelay=2
ethact=dm9000
ethaddr=08:00:3e:26:0a:5b
fileaddr=30000000
filesize=5b89a8
ipaddr=192.168.1.17
machid=7cf
mtddevname=u-boot
mtddevnum=0
mtdids=nand0=jz2440-0
mtdparts=mtdparts=jz2440-0:256k(u-boot),128k(params),2m(kernel),-(rootfs)
netmask=255.255.255.0
partition=nand0,0
serverip=192.168.1.100
stderr=serial
stdin=serial
stdout=serial
Environment size: 607/131068 bytes
修改启动参数，设置波特率为115200，并且记得保存：
SMDK2410 # set bootargs console=ttySAC0,115200 root=/dev/mtdblock3
SMDK2410 # save
重新下载内核并启动：
tftp 30000000 uImage_newkernel; bootm 30000000
打印信息：
## Booting kernel from Legacy Image at 30000000 ...
Image Name: Linux-3.4.2
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 2399640 Bytes = 2.3 MiB
Load Address: 30108000
Entry Point: 30108000
Verifying Checksum ... OK
Loading Kernel Image ... OK
OK
Using machid 0x7cf from environment
Starting kernel ...
Uncompressing Linux... done, booting the kernel.
Booting Linux on physical CPU 0
Linux version 3.4.2 (book@book-desktop) (gcc version 4.3.2 (Sourcery G++ Lite 2008q3-72) ) #1 Fri May 20 12:08:33 CST 2016
CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
CPU: VIVT data cache, VIVT instruction cache
Machine: MINI2440
Memory policy: ECC disabled, Data cache writeback
CPU S3C2440A (id 0x32440001)
S3C24XX Clocks, Copyright 2004 Simtec Electronics
S3C244X: core 400.000 MHz, memory 100.000 MHz, peripheral 50.000 MHz
CLOCK: Slow mode (1.500 MHz), fast, MPLL on, UPLL on
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 16256
Kernel command line: console=ttySAC0,115200 root=/dev/mtdblock3
PID hash table entries: 256 (order: -2, 1024 bytes)
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 64MB = 64MB total
.....
最后打印：
List of all partitions:
1f00 256 mtdblock0 (driver?)
1f01 128 mtdblock1 (driver?)
1f02 5120 mtdblock2 (driver?)
1f03 256640 mtdblock3 (driver?)
No filesystem could mount root, tried: ext3 ext2 cramfs vfat msdos iso9660 romfs
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,3)
Backtrace:
[] (dump_backtrace+0x0/0x10c) from [] (dump_stack+0x18/0x1c)
r6:c38b2000 r5:ffffffea r4:c381df2c
[] (dump_stack+0x0/0x1c) from [] (panic+0x7c/0x1d0)
[] (panic+0x0/0x1d0) from [] (mount_block_root+0x1e0/0x23c)
r3:00000003 r2:c381df2c r1:c381df2c r0:c04e4c20
[] (mount_block_root+0x0/0x23c) from [] (mount_root+0x88/0x108)
[] (mount_root+0x0/0x108) from [] (prepare_namespace+0x110/0x1d0)
r7:c05ac540 r6:c056e764 r5:c056e764 r4:c05ac5a0
[] (prepare_namespace+0x0/0x1d0) from [] (kernel_init+0x164/0x1b8)
r6:00000008 r5:c056df38 r4:c0574b34
[] (kernel_init+0x0/0x1b8) from [] (do_exit+0x0/0x76c)
发现问题：驱动分区信息不对，找不到根文件系统，启动不起来。
查找机器ID:
\board\samsung\smdk2410\smdk2410.c
board_init
gd->bd->bi_arch_number = MACH_TYPE_SMDK2410; // mach_types.h: MACH_TYPE_SMDK2410 = 193
设置机器ID:
set machid 16a // SMDK2440 mach-smdk2440.c
set machid 7CF // mini2440 mach-mini2440.c
板子不同对应的初始化函数不同，而为什么mini2440可以打印，而SMDK2440不能打印数据呢？
可以对照mach-smdk2440.c和mach-mini2440.c中的初始化函数有什么不同。
可以看到mach-smdk2440.c里面时钟设置的不对，外部晶振应该该为12Mhz。
\arch\arm\mach-s3c24xx\mach-smdk2440.c
函数：smdk2440_map_io
s3c24xx_init_clocks(16934400);
修改为：
s3c24xx_init_clocks(12000000);
-重新编译烧写内核，
-启动开发板
-设置成SMDK2440
-看打印信息
打印信息：
Creating 8 MTD partitions on "NAND":
0x000000000000-0x000000004000 : "Boot Agent"
mtd: partition "Boot Agent" doesn't end on an erase block -- force read-only
0x000000000000-0x000000200000 : "S3C2410 flash partition 1"
0x000000400000-0x000000800000 : "S3C2410 flash partition 2"
0x000000800000-0x000000a00000 : "S3C2410 flash partition 3"
0x000000a00000-0x000000e00000 : "S3C2410 flash partition 4"
0x000000e00000-0x000001800000 : "S3C2410 flash partition 5"
0x000001800000-0x000003000000 : "S3C2410 flash partition 6"
0x000003000000-0x000010000000 : "S3C2410 flash partition 7"
dm9000 Ethernet Driver, V1.31
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
s3c2410-ohci s3c2410-ohci: S3C24XX OHCI
s3c2410-ohci s3c2410-ohci: new USB bus registered, assigned bus number 1
s3c2410-ohci s3c2410-ohci: irq 42, io mem 0x49000000
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 2 ports detected
usbcore: registered new interface driver libusual
usbcore: registered new interface driver usbserial
usbcore: registered new interface driver usbserial_generic
USB Serial support registered for generic
usbserial: USB Serial Driver core
usbcore: registered new interface driver ftdi_sio
USB Serial support registered for FTDI USB Serial Device
ftdi_sio: v1.6.0:USB FTDI Serial Converters Driver
usbcore: registered new interface driver pl2303
USB Serial support registered for pl2303
mousedev: PS/2 mouse device common for all mice
s3c2410_wdt: S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics
s3c2410-wdt s3c2410-wdt: watchdog inactive, reset disabled, irq disabled
TCP: cubic registered
NET: Registered protocol family 17
drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
ALSA device list:
No soundcards found.
List of all partitions:
1f00 16 mtdblock0 (driver?)
1f01 2048 mtdblock1 (driver?)
1f02 4096 mtdblock2 (driver?)
1f03 2048 mtdblock3 (driver?)
1f04 4096 mtdblock4 (driver?)
1f05 10240 mtdblock5 (driver?)
1f06 24576 mtdblock6 (driver?)
1f07 212992 mtdblock7 (driver?)
No filesystem could mount root, tried: ext3 ext2 cramfs vfat msdos iso9660 romfs
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,3)
Backtrace:
[] (dump_backtrace+0x0/0x10c) from [] (dump_stack+0x18/0x1c)
r6:c38a9000 r5:ffffffea r4:c381df2c
[] (dump_stack+0x0/0x1c) from [] (panic+0x7c/0x1d0)
[] (panic+0x0/0x1d0) from [] (mount_block_root+0x1e0/0x23c)
r3:00000003 r2:c381df2c r1:c381df2c r0:c04e4c20
[] (mount_block_root+0x0/0x23c) from [] (mount_root+0x88/0x108)
[] (mount_root+0x0/0x108) from [] (prepare_namespace+0x110/0x1d0)
r7:c05ac540 r6:c056e764 r5:c056e764 r4:c05ac5a0
[] (prepare_namespace+0x0/0x1d0) from [] (kernel_init+0x164/0x1b8)
r6:00000008 r5:c056df38 r4:c0574b34
[] (kernel_init+0x0/0x1b8) from [] (do_exit+0x0/0x76c)
可以打印出信息了，不过还是不能启动根文件系统。
===============
NFS网络烧写内核：
nfs 30000000 192.168.1.10:/work/nfs_root/uImage_newkernel
bootm 30000000
========
工具搭建：
1. 交叉编译器：arm-linux-gcc-4.3.2.tar.bz2
2. 新的内核：linux-3.4.2.tar.bz2
交叉编译器搭建：
解压到根目录：
tar xjf arm-linux-gcc-4.3.2.tar.bz2 -C /
修改环境变量：
vi /etc/environment
修改：在后面添加新的编译器 /usr/local/arm/4.3.2/bin/
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/arm/4.3.2/bin/"
1. 下载源码树，分析从u-boot跳转到linux内核启动过程
2. 找到与开发板对应的配置文件，配置并编译最新的内核
3. 烧写到开发板，调试，看串口能否正确打印，能否启动内核
