Only if you think of it in advance, when you fix the standard for where everything goes.
But how many UARTs should you allow for? 2? 16? 256? No matter what you choose, someone many want to build a system with more, and if you choose 256 (or more) then that's getting to be significant wasted address space for people who only have one UART.
All the more so for things that use a lot more address space than half a dozen control registers for a UART. What about 4k (3840x2560) x32 bit frame buffers? Those are 37.5 MB each. Some people want one. Some people want to drive a wall of monitors.
Much more flexible to let people configure their address space how they want and supply a devicetree in ROM / SPI flash etc.
codedokode|2 years ago
brucehoult|2 years ago
But how many UARTs should you allow for? 2? 16? 256? No matter what you choose, someone many want to build a system with more, and if you choose 256 (or more) then that's getting to be significant wasted address space for people who only have one UART.
All the more so for things that use a lot more address space than half a dozen control registers for a UART. What about 4k (3840x2560) x32 bit frame buffers? Those are 37.5 MB each. Some people want one. Some people want to drive a wall of monitors.
Much more flexible to let people configure their address space how they want and supply a devicetree in ROM / SPI flash etc.