The Pi 2 and 3 have 1024MB of memory from 0x00000000 to 0x3EFFFFFF and use the last 16MB for memory mapped IO (0x3F000000 - 0x3FFFFFFF)
I am curious as to why they didn't just start the MMIO at 0x40000000?
Does anyone know?
What we have learned from snippets of information provided over the years is that the VC4 GPU only supports a 1GB address space (which is the reason why the Pi cannot have more than 1GB) and because the GPU needs access to the peripherals they need to fall within that 1GB range.
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