cxp upconn: refactor idle into its submodule

src/gateware/cxp_upconn.py

@@ -1,17 +1,18 @@
 from migen import *
 from migen.genlib.resetsync import AsyncResetSynchronizer
-from migen.genlib.cdc import MultiReg
+from migen.genlib.coding import PriorityEncoder
 
-from misoc.cores.code_8b10b import SingleEncoder, Decoder
-from misoc.interconnect.csr import *
+from misoc.cores.code_8b10b import SingleEncoder
 from misoc.interconnect import stream
+from misoc.interconnect.csr import *
+
 
 class CXP_UpConn(Module, AutoCSR):
-    def __init__(self, pads, tx_fifo_depth=32):
+    def __init__(self, pads, sys_clk_freq, pmod, nfifos=3, fifo_depth=32):
         self.clock_domains.cd_cxp_upconn = ClockDomain()
         self.clk_reset = CSRStorage(reset=1)
-
         self.bitrate2x_enable = CSRStorage()
+        self.tx_enable = CSRStorage()
 
         # # #
 
@@ -26,11 +27,11 @@ class CXP_UpConn(Module, AutoCSR):
                 o_LOCKED=pll_locked,
                 i_RST=ResetSignal("sys"),
                 
-                p_CLKIN1_PERIOD=8, # ns
+                p_CLKIN1_PERIOD=1e9/sys_clk_freq, # ns
                 i_CLKIN1=ClockSignal("sys"),
 
                 # VCO @ 1.25GHz 
-                p_CLKFBOUT_MULT=10, p_DIVCLK_DIVIDE=1,
+                p_CLKFBOUT_MULT=1.25e9/sys_clk_freq, p_DIVCLK_DIVIDE=1,
                 i_CLKFBIN=pll_fb_clk, o_CLKFBOUT=pll_fb_clk, 
 
                 # 20.83MHz (48ns)
@@ -48,115 +49,243 @@ class CXP_UpConn(Module, AutoCSR):
             AsyncResetSynchronizer(self.cd_cxp_upconn, ~pll_locked | self.clk_reset.storage)
         ]
 
-        self.symbol0 = CSR(9)
-        self.symbol1 = CSR(9)
-
-        nfifos = 2
-
-        self.data = [ Signal(8) for _ in range(nfifos)]
-        self.k_symbol = [ Signal() for _ in range(nfifos)]
-        self.stb = [ Signal() for _ in range(nfifos)]
-        
-       
-        self.fifo_full = CSRStatus(nfifos)
-
-
-        self.tx_fifos = []
-        self.tx_encoders = []
-
-        cdr = ClockDomainsRenamer({"write": "sys", "read": "cxp_upconn"})
-
-        # Priority Queue
-        # 0: Trigger packet
-        # 1: IO acknowledgment for trigger packet
-        # 2: All other packets
-        for i in range(nfifos):
-            fifo = cdr(stream.AsyncFIFO([("data", 9)], tx_fifo_depth))
-            # fifo = stream.SyncFIFO([("data", 9)], tx_fifo_depth)            
-            self.tx_fifos.append(fifo)
-            setattr(self.submodules, "tx_fifo" + str(i), fifo)
-            self.sync += [
-                fifo.sink.stb.eq(self.stb[i]),
-                fifo.sink.data.eq(Cat(self.data[i], self.k_symbol[i])),
-                self.fifo_full.status[i].eq(~fifo.sink.ack),
-            ]
-
-        self.sync += [
-                self.stb[0].eq(self.symbol0.re),
-                self.data[0].eq(self.symbol0.r[:8]),
-                self.k_symbol[0].eq(self.symbol0.r[8]),
-                self.stb[1].eq(self.symbol1.re),
-                self.data[1].eq(self.symbol1.r[:8]),
-                self.k_symbol[1].eq(self.symbol1.r[8]),
-        ]
-        self.tx_fifo0_source_data = CSRStatus(9)        
-        self.tx_fifo1_source_data = CSRStatus(9)        
-        self.tx_fifo0_stb = CSRStatus()
-        self.tx_fifo1_stb = CSRStatus()
-
-        self.submodules.tx = UpConn_TX(pads)
-        
-        self.comb += [
-            self.tx_fifo0_source_data.status.eq(self.tx_fifos[0].source.data),
-            self.tx_fifo1_source_data.status.eq(self.tx_fifos[1].source.data),
-            self.tx_fifo0_stb.status.eq(self.tx_fifos[0].source.stb),
-            self.tx_fifo1_stb.status.eq(self.tx_fifos[1].source.stb),
-        ]
-
-        self.sync.cxp_upconn +=[
-            self.tx.data_stb.eq(self.tx_fifos[0].source.stb | self.tx_fifos[1].source.stb),
-            self.tx_fifos[0].source.ack.eq(0),
-            self.tx_fifos[1].source.ack.eq(0),
-            If(self.tx.data_ack,
-                If(self.tx_fifos[0].source.stb,
-                    self.tx.encoder.d.eq(self.tx_fifos[0].source.data[:8]),
-                    self.tx.encoder.k.eq(self.tx_fifos[0].source.data[8]),
-                    self.tx_fifos[0].source.ack.eq(1),
-                ).Elif(self.tx_fifos[1].source.stb,
-                    self.tx.encoder.d.eq(self.tx_fifos[1].source.data[:8]),
-                    self.tx.encoder.k.eq(self.tx_fifos[1].source.data[8]),
-                    self.tx_fifos[1].source.ack.eq(1),
-                ),
-            ),
-        ]
-
-        # DEBUG: remove pads
-        self.specials += Instance("OBUF", i_I=self.cd_cxp_upconn.clk, o_O=pads.n_rx)
-
-class UpConn_TX(Module, AutoCSR):
-    def __init__(self, pads):
-        self.data_ack = Signal()
-        self.data_stb = Signal()
-        self.data_out = CSRStatus(10)
-
-        # # #
-
-        self.submodules.encoder = ClockDomainsRenamer("cxp_upconn")(SingleEncoder(True))
+        self.submodules.fsm = ClockDomainsRenamer("cxp_upconn")(FSM(reset_state="WAIT_TX_ENABLE"))
+        self.submodules.tx_fifos = TxFIFOs(nfifos, fifo_depth)
+        self.submodules.tx_idle = TxIdle()
 
         o = Signal()
-        tx_busy = Signal()
+        tx_en = Signal()
         tx_bitcount = Signal(max=10)
+        tx_wordcount = Signal()
         tx_reg = Signal(10)
 
+        disp = Signal()
+        tx_wordcount = Signal(max=4)
+        priority = Signal(max=nfifos)
+        idling = Signal()
+
+        # startup sequence
+        self.fsm.act("WAIT_TX_ENABLE",
+            NextValue(self.tx_idle.disp_in, 0),
+            NextValue(self.tx_idle.word_idx, 0),
+
+            If(self.tx_enable.storage,
+                NextValue(tx_wordcount, 0),
+                NextValue(tx_bitcount, 0),
+                NextState("LOAD_CHAR")
+            )
+        )
+
+        self.fsm.act("LOAD_CHAR",
+            NextValue(idling, 1),
+            NextValue(self.tx_idle.source_ack, 1),
+            NextValue(tx_reg, self.tx_idle.source_data),
+            NextValue(disp, self.tx_idle.disp_out),
+            NextState("START_TX")
+        )
+
+        self.fsm.act("START_TX",
+            tx_en.eq(1),
+            If((~self.tx_enable.storage) & (tx_wordcount == 3),
+                NextState("WAIT_TX_ENABLE")
+            )
+        )
+
+
+        # CXP 2.1 section 9.2.4 
+        # Higher priority packet can be inserted into a lower priority packet during transmission
+        # Priority lv 0 can be inserted in char boundary of the packet 
+        # Priority lv 1-2 need to be inserted in word boundary of the packet
         self.sync.cxp_upconn += [
-            self.data_ack.eq(0),
-            If(tx_busy,
+            self.tx_fifos.disp_in.eq(disp),
+            self.tx_idle.disp_in.eq(disp),
+
+            If(tx_en,
                 o.eq(tx_reg[0]),
-                tx_reg.eq(Cat(tx_reg[1:], 0))
-            ),
-            If(tx_bitcount != 9,
+                tx_reg.eq(Cat(tx_reg[1:], 0)),
                 tx_bitcount.eq(tx_bitcount + 1),   
-            ).Elif(self.data_stb,
-                tx_busy.eq(1),
+
+
+                # char boundary
+                If(tx_bitcount == 9,
                     tx_bitcount.eq(0),
-                tx_reg.eq(self.encoder.output),
-                self.data_out.status.eq(self.encoder.output),
-                self.encoder.disp_in.eq(self.encoder.disp_out),
-                self.data_ack.eq(1),
+                    If((~self.tx_fifos.pe.n) & (self.tx_fifos.pe.o == 0),
+                        # trigger packet can interrupt at char level
+                        tx_reg.eq(self.tx_fifos.source_data[0]),
+                        self.tx_fifos.source_ack[0].eq(1),
+                        disp.eq(self.tx_fifos.disp_out[0]),
+                    ).Else(
+                        # priority zero doesn't contribute to word count
+                        If(tx_wordcount != 3,
+                            tx_wordcount.eq(tx_wordcount + 1),
+                        ).Else(
+                            tx_wordcount.eq(0),
+                        ),
+
+                        # new word boundary
+                        If(tx_wordcount == 3,
+                            If(~self.tx_fifos.pe.n,
+                                idling.eq(0),
+                                priority.eq(self.tx_fifos.pe.o),
+
+                                self.tx_fifos.source_ack[self.tx_fifos.pe.o].eq(1),
+                                tx_reg.eq(self.tx_fifos.source_data[self.tx_fifos.pe.o]),
+                                disp.eq(self.tx_fifos.disp_out[self.tx_fifos.pe.o]),
+                            ).Else(
+                                idling.eq(1),
+
+                                self.tx_idle.source_ack.eq(1),
+                                tx_reg.eq(self.tx_idle.source_data),    
+                                disp.eq(self.tx_idle.disp_out),
+                            )
+                        ).Else(
+                            If(~idling,
+                                self.tx_fifos.source_ack[priority].eq(1),
+                                tx_reg.eq(self.tx_fifos.source_data[priority]),
+                                disp.eq(self.tx_fifos.disp_out[priority]),
+                            ).Else(
+                                self.tx_idle.source_ack.eq(1),
+                                tx_reg.eq(self.tx_idle.source_data),    
+                                disp.eq(self.tx_idle.disp_out),
+                            )
+                        ),       
+                    )
+                )
             ).Else(
-                tx_busy.eq(0),
                 o.eq(0)
             )
         ]
+        # DEBUG: remove pads
+        self.encoded_data = CSRStatus(10)
+        self.sync.cxp_upconn +=[
+            If(tx_bitcount == 0,
+                self.encoded_data.status.eq(tx_reg),
+            )
+        ]
        
-        self.specials += Instance("OBUF", i_I=o, o_O=pads.p_tx)
+        ninth_bit = Signal()
+        word_bound = Signal()
+
+        p0 = Signal()
+        p3 = Signal()
+        self.comb += [
+           ninth_bit.eq(tx_bitcount == 9),
+           word_bound.eq(tx_wordcount == 3),
+           p0.eq(self.tx_idle.word_idx == 0),
+           p3.eq(self.tx_idle.word_idx == 3),
+        ] 
+        self.specials += [
+            # debug sma
+            Instance("OBUF", i_I=o, o_O=pads.p_tx),
+            Instance("OBUF", i_I=self.cd_cxp_upconn.clk, o_O=pads.n_rx),
+
+            # pmod 0-7 pin
+            Instance("OBUF", i_I=o, o_O=pmod[0]),
+            Instance("OBUF", i_I=self.cd_cxp_upconn.clk, o_O=pmod[1]),
+            Instance("OBUF", i_I=~self.tx_fifos.pe.n, o_O=pmod[2]),
+            Instance("OBUF", i_I=ninth_bit, o_O=pmod[3]),
+            Instance("OBUF", i_I=word_bound, o_O=pmod[4]),
+            Instance("OBUF", i_I=idling, o_O=pmod[5]),
+            # Instance("OBUF", i_I=self.tx_fifos.source_ack[0], o_O=pmod[6]),
+            # Instance("OBUF", i_I=self.tx_fifos.source_ack[2], o_O=pmod[6]),
+            # Instance("OBUF", i_I=self.tx_fifos.source_ack[1], o_O=pmod[7]),
+            Instance("OBUF", i_I=p0, o_O=pmod[6]),
+            Instance("OBUF", i_I=p3, o_O=pmod[7]),
+        ]
+        self.symbol0 = CSR(9)
+        self.symbol1 = CSR(9)
+        self.symbol2 = CSR(9)
+
+        self.sync += [
+            self.tx_fifos.sink_stb[0].eq(self.symbol0.re),
+            self.tx_fifos.sink_data[0].eq(self.symbol0.r),
+            self.tx_fifos.sink_stb[1].eq(self.symbol1.re),
+            self.tx_fifos.sink_data[1].eq(self.symbol1.r),
+            self.tx_fifos.sink_stb[2].eq(self.symbol2.re),
+            self.tx_fifos.sink_data[2].eq(self.symbol2.r),
+        ]
+
+class TxFIFOs(Module):
+    def __init__(self, nfifos, fifo_depth):
+        self.disp_in = Signal()
+        self.disp_out = Array(Signal() for _ in range(nfifos))
+        
+        self.sink_stb = Signal(nfifos)
+        self.sink_ack = Signal(nfifos) 
+        self.sink_data = [Signal(9) for _ in range(nfifos)]
+        
+        self.source_ack = Array(Signal() for _ in range(nfifos))
+        self.source_data = Array(Signal(10) for _ in range(nfifos))
+
+        # # #
+
+        source_stb = Signal(nfifos)
+
+        for i in range(nfifos):
+            cdr = ClockDomainsRenamer({"write": "sys", "read": "cxp_upconn"})
+            fifo = cdr(stream.AsyncFIFO([("data", 9)], fifo_depth))
+            encoder = ClockDomainsRenamer("cxp_upconn")(SingleEncoder(True))
+            setattr(self.submodules, "tx_fifo" + str(i), fifo)
+            setattr(self.submodules, "tx_encoder" + str(i), encoder)
+            self.sync += [
+                fifo.sink.stb.eq(self.sink_stb[i]),
+                self.sink_ack[i].eq(fifo.sink.ack),
+                fifo.sink.data.eq(self.sink_data[i]),
+            ]
+            self.sync.cxp_upconn += [
+                encoder.d.eq(fifo.source.data[:8]),
+                encoder.k.eq(fifo.source.data[8]),
+                encoder.disp_in.eq(self.disp_in),
+                self.disp_out[i].eq(encoder.disp_out),
+
+                source_stb[i].eq(fifo.source.stb),
+                fifo.source.ack.eq(self.source_ack[i]),
+                self.source_data[i].eq(encoder.output),
+                # reset ack after asserted 
+                If(self.source_ack[i], self.source_ack[i].eq(0)),
+            ]
+        # FIFOs transmission priority
+        self.submodules.pe = PriorityEncoder(nfifos)
+        self.comb += self.pe.i.eq(source_stb)
+
+class TxIdle(Module):
+    def __init__(self):
+        self.disp_in = Signal()
+        self.disp_out = Signal()
+
+        self.word_idx = Signal(max=4)
+        self.source_ack = Signal()
+        self.source_data = Signal(10)
+        
+        # # #
+
+        # CXP 2.1 section 9.2.5 
+        IDLE_CHARS = Array([
+            #[data, k]
+            [0b10111100, 1], #K28.5
+            [0b00111100, 1], #K28.1
+            [0b00111100, 1], #K28.1
+            [0b10111100, 0], #D28.5
+        ])
+
+        encoder = ClockDomainsRenamer("cxp_upconn")(SingleEncoder(True))
+        self.submodules += encoder
+
+        self.sync.cxp_upconn += [
+            encoder.d.eq(IDLE_CHARS[self.word_idx][0]),
+            encoder.k.eq(IDLE_CHARS[self.word_idx][1]),
+            encoder.disp_in.eq(self.disp_in),
+            self.disp_out.eq(encoder.disp_out),
+            self.source_data.eq(encoder.output),
+
+            If(self.source_ack,
+                # reset after asserted
+                self.source_ack.eq(0),
+
+                If(self.word_idx != 3,
+                   self.word_idx.eq(self.word_idx + 1),
+                ).Else(
+                    self.word_idx.eq(0),
+                )
+            ),
+        ]