I'm trying to understand the RPi memory map as shown in the BCM2857 reference (http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf) Pi memory map

Is a "Bus Address" the same as a control address; i.e. generated from the virtual address and used to select particular hardware devices?

Why are there are multiple SDRAM and IO peripheral regions in the video core address space? I thought they might be the different peripheral devices that are all mapped to the 0x7Exxxxxx range, but that doesn't make sense from the layout of the diagram, so are these the other video core peripherals? Any idea where I can find out what these peripherals are?

If the VC MMU generates bus addresses for IO peripherals in the 0x7F range, why do I have to use the 0x3f base when mapping an IO device? Is the 0x7F range just for the VC?

(Yes, multiple questions, but too small to ask individually?)

  • 1
    You may be better off asking on the raspberrypi.org bare metal forum. – joan Jan 22 '20 at 16:17

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