3、烧写映像文件到SPI Flash
以16M SPI Flash为例。
1）地址空间说明
| 1M | 4M | 11M |
|---------------|---------------|---------------|
| boot | kernel | rootfs |
以下的操作均基于图示的地址空间分配，您也可以根据实际情况进行调整。
2）烧写u-boot
sf probe 0
mw.b 82000000 ff 100000
tftp 0x82000000 u-boot-hi3520D.bin
sf probe 0
sf erase 0 100000
sf write 82000000 0 100000
reset
3）烧写内核
mw.b 82000000 ff 400000
tftp 82000000 uImage_hi3520d
sf probe 0
sf erase 100000 400000
sf write 82000000 100000 400000
4) 烧写文件系统
mw.b 82000000 ff b00000
tftp 0x82000000 rootfs_uclibc_256k.jffs2
sf erase 500000 b00000
sf write 82000000 500000 b00000
5）设置启动参数
setenv bootargs 'mem=64M console=ttyAMA0,115200 root=/dev/mtdblock2 rootfstype=jffs2 mtdparts=hi_sfc:1M(boot),4M(kernel),11M(rootfs)'
setenv bootcmd 'sf probe 0;sf read 0x82000000 0x100000 0x400000;bootm 0x82000000'
saveenv
我的虚拟机服务器上的系统镜像：
root@ubuntu:/tftpboot# ls
rootfs_uclibc_256k.jffs2 u-boot_hi3520d.bin uImage_hi3520d_full
hisilicon # mw.b 82000000 ff 400000
hisilicon # tftp 82000000 uImage_hi3520d_full
Hisilicon ETH net controler
miiphy_register: non unique device name '0:3'
miiphy_register: non unique device name '0:2'
MAC: 00-00-23-34-45-66
UP_PORT : phy status change : LINK=DOWN : DUPLEX=FULL : SPEED=100M
UP_PORT : phy status change : LINK=UP : DUPLEX=FULL : SPEED=100M
TFTP from server 192.168.15.1xx; our IP address is 192.168.15.1xx
Download Filename 'uImage_hi3520d_full'.
Download to address: 0x82000000
Downloading: #################################################
done
Bytes transferred = 3196076 (30c4ac hex)
hisilicon # sf probe 0
16384 KiB hi_sfc at 0:0 is now current device
hisilicon # sf eras sf write 82000000 100000 400000
sf - SPI flash sub-system
hisilicon # sf probe 0
16384 KiB hi_sfc at 0:0 is now current device
hisilicon # sf erase 100000 400000
Erasing at 0x500000 -- 100% complete.
hisilicon # sf write 82000000 100000 400000
Writing at 0x500000 -- 100% complete.
hisilicon # mw.b 82000000 ff b00000
hisilicon # tftp 0x82000000 rootfs_uclibc_256k.jffs2
Hisilicon ETH net controler
miiphy_register: non unique device name '0:3'
miiphy_register: non unique device name '0:2'
MAC: 00-00-23-34-45-66
UP_PORT : phy status change : LINK=DOWN : DUPLEX=FULL : SPEED=100M
UP_PORT : phy status change : LINK=UP : DUPLEX=FULL : SPEED=100M
TFTP from server 192.168.15.1xx; our IP address is 192.168.15.1xx
Download Filename 'rootfs_uclibc_256k.jffs2'.
Download to address: 0x82000000
Downloading: #################################################
done
Bytes transferred = 6976840 (6a7548 hex)
hisilicon # sf erase 500000 b00000
Erasing at 0x1000000 -- 100% complete.
hisilicon # setenv bootargs 'mem=64M console=ttyAMA0,115200 root=/dev/mtdblock2 rootfstype=jffs2 mtdparts=hi_sfc:1M(boot),4M(kernel),11M(rootfs)
hisilicon # setenv bootcmd 'sf probe 0;sf read 0x82000000 0x100000 0x400000;bootm 0x82000000'
hisilicon # saveenv
Saving Environment to SPI Flash...
Erasing SPI flash, offset 0x00080000 size 256K ...done
Writing to SPI flash, offset 0x00080000 size 256K ...done
hisilicon # reset
执行后出现：
VFS: Mounted root (jffs2 filesystem) on device 31:2.
Freeing init memory: 140K
Kernel panic - not syncing: No init found. Try passing init= option to kernel. See Linux Documentation/init.txt for guidance.
很明显是根文件系统上的linuxrc没有被执行，官方给的需要参数还是存在问题的，于是我在传参中指定了init进程的位置。
hisilicon # setenv bootargs 'mem=64M console=ttyAMA0,115200 root=/dev/mtdblock2 rootfstype=jffs2 mtdparts=hi_sfc:1M(boot),4M(kernel),11M(rootfs),init=/linuxrc‘
出现了下面的这种情况：
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)
参考网络的一些说法，rootfs_uclibc_256k.jffs2可能没有被烧写到正确的位置，不过我看了内核启动打印的信息，地址是正确的，也有可能是我没真正把rootfs烧写了spi flash 上，于是我用tftp重新烧写了rootfs，启动后果然是：
VFS: Mounted root (jffs2 filesystem) on device 31:2.
Freeing init memory: 140K
Kernel panic - not syncing: Attempted to kill init!