[U-Boot-Users] CFG_MONITOR_BASE < CFG_FLASH_BASE
Leonid at a-k-a.net
Thu May 17 01:04:23 CEST 2007
On Wednesday, May 16, 2007 3:11 PM Timur Tabi wrote:
> I'm not asking if I can
> boot from RAM, I'm asking why would someone think it could be done?
> anything, 14.2.1
> re-inforces my point: if booting from RAM doesn't make sense, why are
> many board header
> files configured to enable it?
It's too strong a statement "booting from RAM doesn't make sense". Of
course, under "booting from RAM" I mean that u-boot runs from RAM and
thus its image must be compiled this way. U-boot image and environment
variables can be still on the flash (I assume the system has one) and
some other (first stage) bootloader fetches u-boot from there, copies to
RAM and starts it. Note that u-boot environment variables stay on the
flash all the time.
As a matter of fact, such scheme is widely used for Xilinx FPGA embedded
cores (both Microblaze and PPC) as well as for ARM CPUs. It's not
approved by many experts and I don't wish to start discussion here
whether such approach is the best in certain circumstances, but it
definitely makes a lot of sense.
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