>I am confused here. You mention above that the address of the rootfs is
>determined based on its size. So you do know the memory that would be needed
>for the rootfs? Also, how does calculating the amount of RAM left over for the
>kernel help. I mean, what if the kernel is bigger than the amount of >left
>over memory? Can that not happen if you don't know the amount of memory that
>would be needed for the kernel as you mention above.
Sorry, maybe I misused the term "kernel memory". I am referring to the amount
of physical ram available for the kernel to use:
From the kernel parameter docs:
```
mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
Amount of memory to be used when the kernel is not able
to see the whole system memory or for test.
[X86] Work as limiting max address. Use together
with memmap= to avoid physical address space collisions.
Without memmap= PCI devices could be placed at addresses
belonging to unused RAM.
```
We know the memory that is needed based for the rootfs "in runtime", it's not
something we can compile into u-boot (if you add a new binary to the rootfs
then it's bigger).
We don't want the kernel to be touching this piece of memory that emulates the
mtd partition.
I hope this clears up the usecase.
Tomas
