hwstub: add proper PP support

- drop support for PP500x: it's very different from other PP and although
  it would be possible to support them, I don't have one to test the code
- make sure only the CPU is started
- add PP descriptor to report chip ID and revision
- add code in shell and lua to support pp (no register description yet)
- compile for ARMv4 because PP502x is an ARM7TDMI

Change-Id: I36c4e465dfc2cfdfe7433b2f65cc8f6f0720fe62

utils/hwstub/tools/lua/pp.lua

@@ -0,0 +1,62 @@
+---
+--- Chip Identification
+---
+
+PP = { info = {} }
+
+local h = HELP:create_topic("PP")
+h:add("This table contains the abstraction of the different device blocks for the Portal Player / GoForce")
+h:add("It allows one to use higher-level primitives rather than poking at register directly.")
+h:add("Furthermore, it tries as much as possible to hide the differences between the different PP families.")
+
+local function identify(name, family, desc)
+    PP.chipid = hwstub.dev.pp.chipid
+    PP.info.chip = name
+    PP.info.revision = hwstub.dev.pp.rev
+    PP.desc = desc
+    PP.family = family
+    print("Chip identified as " .. name ..", ROM " .. PP.info.revision)
+    if not hwstub.soc:select(desc) then
+        print("Looking for soc " .. desc .. ": not found. Please load a soc by hand.")
+    end
+end
+
+local hh = h:create_topic("is_pp611x")
+hh:add("PP.is_pp611x() returns true if the chip ID reports a PP611x")
+
+function PP.is_pp611x()
+    return hwstub.dev.pp.chipid >= 0x6110
+end
+
+hh = h:create_topic("is_pp502x")
+hh:add("PP.is_pp502x() returns true if the chip ID reports a PP502x")
+
+function PP.is_pp502x()
+    return hwstub.dev.pp.chipid >= 0x5020 and hwstub.dev.pp.chipid < 0x6100
+end
+
+hh = h:create_topic("is_pp500x")
+hh:add("PP.is_pp500x() returns true if the chip ID reports a PP500x")
+
+function PP.is_pp500x()
+    return hwstub.dev.pp.chipid >= 0x5000 and hwstub.dev.pp.chipid < 0x5010
+end
+
+if PP.is_pp611x() then
+    identify("PP6110x (aka GoForce6110)", "pp6110", "pp6110")
+elseif PP.is_pp502x() then
+    identify("PP502x", "pp502x", "pp502x")
+elseif PP.is_pp500x() then
+    identify("PP500x", "pp500x", "pp500x")
+else
+    print(string.format("Unable to identify this chip as a PP: chipid=0x%x", hwstub.dev.pp.chipid));
+end
+
+hh = h:create_topic("debug")
+hh:add("PP.debug(...) prints some debug output if PP.debug_on is true and does nothing otherwise.")
+
+PP.debug_on = false
+
+function PP.debug(...)
+    if PP.debug_on then print(...) end
+end