DDR工作频率  在600MHZ. include/configs/board953x.h #define CFG_PLL_FREQ            CFG_PLL_650_600_200 #define  CFG_DDR_REFRESH_VAL            0x4138   (default 12c) 0x0100 0001 0011 1000 ./board/atheros/common/init-953x.c:59:#define CFG_DDR2_SCORPION_CAS…

design: when uboot load kerne failed,we can switch to stanbdy system; how to realize: when boot fail, we can let uboot env bootKenrelFailCount++, then save to uboot_env partiton.    watchdog timeout will trigger cpu reset, when bootKernelFailCount bi…

By passing the kernel panic parameter, the system automatically resets after 3 seconds when kernel panic happen example: bootargs  'board=xxxxx console=ttyS0,115200 ubi.mtd=overlay rootfs=/dev/mtdblock:rootfs  rootfstype=squashfs noinitrd init=/sbin/…

uboot commad test test - minimal test like /bin/sh so we can use test command to some judge for example, test –n $uenvcmd    test var uenvcmd length !eq  zero detail learning you  can reference url: https://www.cnblogs.com/tankblog/p/6160808.html Not…

1.uboot阶段对Flash的分区 (1).所谓分区,就是对Flash进行分块管理. (2).PC机等产品中,因为大家都是在操作系统下使用硬盘的,整个硬盘由操作系统统一管理,操作系统会使用文件系统帮助我们管理磁盘空间.(管理保证了文件之间不会相互堆叠),于是乎使用者不用自己太多在意分区问题. (3).在uboot中是没有操作系统的,因此我们对flash(相当于硬盘)的管理必须事先使用分区界定(实际上在uboot中和kernel中都有一个分区表,分区表就是我们在做系统移植时对Flash的整体管理…

pseudocode: If(reset_button was pressed ) { Change  uboot env bootslot^1 }…

find cpu datasheet , watchdog relate registers: 0x18060008 watchdong timer control 0x1806000c watchdog timer we can read and write watchdog register under uboot console: #mw 0x1806000c 0xffffffff  1 #mw 0x1806000c 0x10000000  1 #mw 0x18060008    0x3 …

reference :https://github.com/lentinj/u-boot/blob/master/doc/README.autoboot how to enable protect sonsole in uboot stage ? we can add follow contest in include/configs/xxxx.h +// add by panzidong for support  protect uboot console +#define CONFIG_AU…

reference: uboot_dir/doc/README.distro Linux distributions are faced with supporting a variety of boot mechanisms,environments or bootloaders (PC BIOS, EFI, U-Boot, Barebox, ...). This makeslife complicated. Worse, bootloaders such as U-Boot have a c…

reference: http://www.denx.de/wiki/DULG/UBootCmdGroupExec => help source source - run script from memory Usage: source [addr] - run script starting at addr - A valid image header must be present => With the source command you can run "shell&quo…