Hi Darwin,
Darwin Chen wrote:
I have some questions about uClinux and bootloader, the answer must be in
the kernel source code, but I can't find it, and google master can't yet.
So, the questions are:
1.The bootloader remaps the SDRAM/Flash address, the different bootloader
has different address mapping, so, is uClinux remaps again to it's own
address mapping? I guess this answer should be "No", but I can't confirm it.
No, uClinux does not remap RAM or flash after after the bootloader.
The target boards in uClinux are setup to work with whatever the
bootloader does on that board.
(That is not to say that uClinux could not do remapping - it is
just that by convention it doesn't).
2. How to tell the uClinux about bootloader's address mapping? If I change
the bootloader's address mapping, Which kernel source code should be
changed?
In modern 2.6 version kernels the RAM mapping is configurable
at "make config" for at least m68k/coldfire and arm, maybe others
too. In older 2.4 kernels it was often hard coded into platform
specific code for that board support.
Flash mappings depend on what MTD map driver you are using.
3. I have a W90N740-based boards, there is only 1MB flash and 4MB SDRAM, so
I want to set the address mapping as following:
Before the bootloader remaps the address space:
0x00000000 - 0x0000efff 60KB bootloader
0x0000f000 - 0x0000ffff 4KB the parameters of uClinux and bootloaders
0x00010000 - 0x0009ffff 576KB the kernel image
0x000A0000 - 0x000FFFFF 384KB the romfs image.
After the address space is following after the bootloader remaps:
0x00000000 - 0x003fffff 4MB SDRAM
0x7F000000 - 0x7F0FFFFF 1MB Flash.
Is uclinux must request 32KB space for parameter? I think there is no so
much parameters to boot uclinux.
Do you mean boot args?
Regards
Greg
------------------------------------------------------------------------
Greg Ungerer -- Chief Software Dude EMAIL: [EMAIL PROTECTED]
Secure Computing Corporation PHONE: +61 7 3435 2888
825 Stanley St, FAX: +61 7 3891 3630
Woolloongabba, QLD, 4102, Australia WEB: http://www.SnapGear.com
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