How to porting u-boot to my own board?

Hi LiangYi,

> > First, I want to ask you the relation between u-boot, flash, sdram and epcs4.

u-boot is an application (a boot monitor) that can be stored in flash or an epcs device.

When the cpu is reset, u-boot is copied to sdram by: itself (if it is stored at the reset address);

or the epcs controller boot code.

> > Furthermore, where are various kinds of files(uImage, .bin, .sof, .flash, .srec and so on) run

> or properly stored in for u-boot?

uimage or an "img" file is most commonly used to store a kernel binary (but it can be used

to store data, ram disk images, scripts, etc.). The kernel image can be compressed. It can be stored

anywhere you want. In flash, in ram (downloaded by u-boot via serial port, TFTP or NFS), in an epcs

device (if the device is large enough). An image file is nothing more than a small header prepended

to your original file. The header contains information about the binary data that follows and includes

a 32-bit CRC for the data, and a 32-bit CRC for the header itself.

u-boot.bin is simply the u-boot .text, .data, .rodata, etc. u-boot.srec is an S-record file for

u-boot ... it's just a convenience for use with EPROM programmers, etc. The flash file is used by

nios2-flash-programmer (it just happens to in S-record format).

> Is u-boot stored in flash or EPCS?

Either ... that's up to you.

> > Finally, what procedure should I follow and test step by step in order to achieve u-boot,

> boot uClinux on my board?

Create an image file for uClinux, load it onto your board, then execute the u-boot "bootm"

command (this is all in the u-boot README).

Regards,

--Scott