I am trying to run Linux on an Arduino Yun board. The Arduino board contains an Atheros AR9331 chipset
On U-Boot these are the steps I am doing:
1- Download the kernel:
ar7240> tftp 0x80060000 openwrt-ar71xx-generic-uImage-lzma.bin;
Load address: 0x80060000
Loading: #################################################################
#################################################################
#################################################################
#################################################################
######################
done
Bytes transferred = 1441863 (160047 hex)
2- Erase Flash in order to copy the kernel:
ar7240> erase 0x9fEa0000 +0x160047
Error: end address (0xa0000046) not in flash!
Bad address format
This is the problem It seems that 0x9fEa0000 +0x160047 exceeds the total size of the flash.
So my questions are:
1- How can I figure the total amount of memory reserved for the flash in Uboot (From which address it starts and ends), I am thinking about changing 0x9fEa0000 by a fewer address but I'm afraid I can harm other things
This is the output of the help:
ar7240> help
? - alias for 'help'
boot - boot default, i.e., run 'bootcmd'
bootd - boot default, i.e., run 'bootcmd'
bootm - boot application image from memory
cp - memory copy
erase - erase FLASH memory
help - print online help
md - memory display
mm - memory modify (auto-incrementing)
mtest - simple RAM test
mw - memory write (fill)
nm - memory modify (constant address)
ping - send ICMP ECHO_REQUEST to network host
printenv- print environment variables
progmac - Set ethernet MAC addresses
reset - Perform RESET of the CPU
run - run commands in an environment variable
setenv - set environment variables
tftpboot- boot image via network using TFTP protocol
version - print monitor version
2- Is there someone experienced with Atheros AR9331 chipset who can help me find the Flash mapping (From where it starts and ends) from the datasheet
You can determine the flash layout from the kernel boot command line. Either run the printenv command in u-boot or boot into the existing kernel and look through the boot log. You need to find something like the following:
(There are plenty of guides on the internet, I took this one from https://finninday.net/wiki/index.php/Arduino_yun, your board may or may not be the same).
linino> printenv
bootargs=console=ttyATH0,115200 board=linino-yun mem=64M rootfstype=squashfs,jffs2 noinitrd mtdparts=spi0.0:256k(u-boot)ro,64k(u-boot-env)ro,14656k(rootfs),1280k(kernel),64k(nvram),64k(art),15936k@0x50000(firmware)
bootcmd=bootm 0x9fea0000
This means there are the following partitions:
u-boot 0 to 256K (0x0 - 0x40000)
u-boot-env 256k to 320k (0x40000 - 0x50000)
rootfs (squashfs) 320k to 14976k (0x50000 - 0xea0000)
kernel 14976k to 16256k (0xea0000 - 0xfe0000)
nvram 16256k to 16320k (0xfe0000 - 0xff0000)
art 16320k to 16384k (0xff0000 - 0x1000000)
The rootfs partition is 14M, which is much larger than the rootfs image file (less than 8MB) so in theory you can move the kernel image at a lower address. For this you will need to modify the kernel boot line in the u-boot environment block (rootfs aand kernel partition sizes) and the bootcmd parameter so the u-boot know where the new kernel is located.
Flash is mapped to 0x9f000000 so the value in the bootcmd should be 0x9f000000 + the offset of the kernel in bytes.
What I am not sure about is if there is an overlay filesystem for any persistent changes to the flash. Can you boot into the existing system and post the output of df -h and cat /proc/mounts?