Object model updates for AHB and AXI

[mhtwn]

Related issue:

Type of change: other enhancement

Impact: no functional change

Development Phase: implementation

Release Notes

An example representation of a port with AXI protocol:

      "signalNamePrefix" : "axi4_mem_port",
      "width" : 32,
      "protocol" : {
        "specification" : {
          "name" : "AXI Protocol",
          "version" : "4",
          "_types" : [ "OMSpecification" ]
        },
        "_types" : [ "AXI", "AMBA", "OMProtocol" ]
      },

An example representation of a port with AHB-Lite protocol:

      "signalNamePrefix" : "ahb_sys_port",
      "width" : 32,
      "protocol" : {
        "specification" : {
          "name" : "AHB Lite Protocol",
          "version" : "3",
          "_types" : [ "OMSpecification" ]
        },
        "_types" : [ "AHB", "AMBA", "OMProtocol" ]
      },

[mwachs5]

I'd like @aisha-w-sifive and/or @jmilstead-sifive feedback on this...

[aisha-w-sifive]

So it is "OMAXI4", "OMAXI4_Lite", "OMAHB", "OMAHB_Lite"? If so, LGTM, should run fine in docs.

[jmilstead-sifive]

Maybe a naïve question, but why include both AXI4 and AMBA if AXI4 extends AMBA? These are all AMBA. Is this to allow for future non-AMBA variants of AXI/APB/AHB?

[mwachs5]

why is this called "specification" when the others are called "Protocol"?

[mhtwn]

Good point - I haven't edited the description for TL, but I can update it - do you think mentioning UL, UH and CS will also be a good idea?

[mwachs5]

for that I'd defer to @hcook or @terpstra