dev-amdgpu: Refactor MMIO interface for SDMA engines

Currently the amdgpu simulated device is assumed to be a Vega10. As a
result there are a few things that are hardcoded. One of those is the
number of SDMAs. In order to add a newer device, such as MI100+, we need
to enable a flexible number of SDMAs.

In order to support a variable number of SDMAs and with the MMIO offsets
of each device being potentially different, the MMIO interface for SDMAs
is changed to use an SDMA class method dispatch table with forwards a
32-bit value from the MMIO packet to the MMIO functions in SDMA of the
format `void method(uint32_t)`. Several changes are made to enable this:

 - Allow the SDMA to have a variable MMIO base and size. These are
   configured in python.
 - An SDMA class method dispatch table which contains the MMIO offset
   relative to the SDMA's MMIO base address.
 - An updated writeMMIO method to iterate over the SDMA MMIO address
   ranges and call the appropriate SDMA MMIO method which matches the
   MMIO offset.
 - Moved all SDMA related MMIO data bit twiddling, masking, etc. into
   the MMIO methods themselves instead of in the writeMMIO method in
   SDMAEngine.

Change-Id: Ifce626f84d52f9e27e4438ba4e685e30dbf06dbc
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/70040
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
8 files changed