On Thu, Oct 1, 2020 at 9:19 PM Florian Fainelli [off-list ref] wrote:

The physical memory map looks like this:

0..3GB -> DRAM
3GB..4GB -> Registers, Boot ROM, Boot SRAM
4GB..12GB -> DRAM extension

So plenty of highmem, and then with LPAE you have
theoretically 12 GB of RAM. In an ARM32 system?

I think Arnd is gonna love this system for our highmem
experiments if that is something that is going to happen
often... Is that DRAM extension often mounted and
used?

quoted

Are these Broadcom chips hard to get for me?

Yes they are hard for you to get.

Isn't one of them this beast:
https://www.ebay.com/c/502488121

Or do you mean that this device is locked down like
a fortress and not really hackable? There seems to
be a UART on the back and all.

Have you got your hands on a Raspberry Pi 4? That one would be
quite similar to one of our Broadcom STB chips (7211) and I would be
curious to know if it even works there.

Pi 3 and 4 are 64bit Cortex A53 and A72 CPUs IIUC, so they
are in arch/arm64 and does not have this problem.

Your systems are curiously interesting, there is copious
highmem etc.

Yours,
Linus Walleij

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