Andy Fleming wrote:
On Wed, Aug 27, 2008 at 12:16 AM, Ajeesh Kumar ajeesh@tataelxsi.co.in wrote:
hi sir/madam,
I'm using a MPC8548E processor(power pc) also, i've interfaced a nor flash of 128 MB to the processor. i've read few documents and got to know that the uboot.bin should be programmed at 0xfff80000. Also, when i saw the uboot.bin size it was 512K. so, it could fit between 0xfff80000 - 0xffffffff. I 'M USING ABATRON BDI2000/BDI3000 FOR THIS. Now my question is:
- If i'm making changes(addition/deletion of code) to the bootloader(uboot
1.2) and re compile it, i believe that the size of the uboot.bin will get changed i.e >/< 512K. NOW AT WHICH LOCATION I SHOULD FLASH THE UBOOT.BIN(SIZE IS NOT EQUAL TO 512) FOR Eg. If my uboot.bin size is >512K ?????
Well, it's not likely you will change the size of the binary. You see, the 512K size is a result of a quirk of the 85xx platform. The reset vector is at 0xfffffffc, but we define the base address to be 0xfff80000, so we fill in the space between, and it's 512K.
The result is, you don't need to mind the size, unless you grow the compiled output by over 200K. Try to avoid that ;)
Andy
Hi Andy,
I was looking at the MPC8548CDS config. The memory map is: 0xFFF80000 256K - u-boot 0xFFFC0000 128K - env 0xFFFE0000 128K - reset vector & bootpage (only one 4K page used!)
Putting the env between u-boot and the reset vector is a horrible thing to do. As a result, the top page of flash is almost entirely unused and is very difficult to use.
I have a EP8548 config (whose origins was the MPC8548CDS config) that I modified to use this memory map: 0xFFFA0000 128K - env 0xFFFC0000 256K - incl reset vector & bootpage
Is there any reason *not* to do this? (The only downside I can think of is that existing boards with the CDS-style map would get their env erased when reprogrammed with a revised memory map u-boot, but that is easy enough to recover from.)
Best regards, gvb