pipeline GW: add docs & remove unused code

src/gateware/cxp_pipeline.py

@@ -265,46 +265,6 @@ class TX_Test_Packet(Module, AutoCSR):
 
         # # #
 
-        # testdata_src = stream.Endpoint(upconn_layout)
-        
-        # # Section 9.9.2 (CXP-001-2021)
-        # # 0x00, 0x01 ... 0xFF need to be send 16 times 
-        # # cnt[8:12] is used to count up 16 times while cnt[:8] is the data 
-        # cnt = Signal(max=0x1000)
-        # clr_cnt = Signal()
-        # inc_cnt = Signal()
-
-        # self.sync += [
-        #     If(clr_cnt,
-        #         cnt.eq(cnt.reset),
-        #     ).Elif(inc_cnt,
-        #         cnt.eq(cnt + 1),
-        #     ),
-        # ]
-
-        # self.submodules.fsm = fsm = FSM(reset_state="IDLE")
-        
-        # fsm.act("IDLE",
-        #     clr_cnt.eq(1),
-        #     If(self.stb.re,
-        #        NextState("WRITE")
-        #     )
-        # )
-
-        # fsm.act("WRITE",
-        #     testdata_src.stb.eq(1),
-        #     testdata_src.data.eq(cnt[:8]),
-        #     testdata_src.k.eq(0),
-        #     If(cnt == 0xFFF,
-        #         testdata_src.eop.eq(1),
-        #         If(testdata_src.ack, NextState("IDLE"))
-        #     ).Else(
-        #         inc_cnt.eq(testdata_src.ack)
-        #     )
-        # )
-
-        # TODO: figure out why only 16 times doesn't work on the decoder
-
         self.submodules.test_pattern_src = test_pattern_src = Code_Source(upconn_layout, [*range(0x100)]*16, [0]*0x100*16)
         self.submodules.pak_type_inserter = pak_type_inserter = Code_Inserter(upconn_layout, [0x04]*4, [0]*4)
         self.submodules.pak_wrp = pak_wrp = Packet_Wrapper(upconn_layout)
@@ -314,7 +274,6 @@ class TX_Test_Packet(Module, AutoCSR):
         ]
 
         self.source = pak_wrp.source
-
         self.sync += [
             test_pattern_src.stb.eq(self.stb.re),
             If(self.stb.re,
@@ -430,7 +389,7 @@ class CXP_Data_Packet_Decode(Module):
             )
         )
 
-        # TODO: decode packet type here
+        # TODO: decode all packet type here
 
         cnt = Signal(max=0x100)
 
@@ -455,6 +414,9 @@ class CXP_Data_Packet_Decode(Module):
             )
         )
 
+        # Section 9.9.1 (CXP-001-2021)
+        # the received test data packet (0x00, 0x01 ... 0xFF) 
+        # need to be compared against the local test sequence generator
         fsm.act("VERIFY_TEST_PATTERN",
             self.sink.ack.eq(1),
             If(self.sink.stb,