soc/rtio: separate PHY, add OE and fine timestamp in FIFO

soc/artiqlib/rtio/__init__.py

@@ -3,10 +3,14 @@ from migen.bank.description import *
 from migen.genlib.fifo import SyncFIFOBuffered
 from migen.genlib.cdc import MultiReg
 
+from types import SimpleNamespace
+
+from artiqlib.rtio import phy
+
 class RTIOBankO(Module):
-	def __init__(self, channels, counter_width, fifo_depth):
+	def __init__(self, channels, counter_width, fine_ts_width, fifo_depth):
 		self.sel = Signal(max=len(channels))
-		self.timestamp = Signal(counter_width)
+		self.timestamp = Signal(counter_width+fine_ts_width)
 		self.value = Signal()
 		self.writable = Signal()
 		self.we = Signal()
@@ -19,14 +23,14 @@ class RTIOBankO(Module):
 		self.sync += [
 			counter.eq(counter + 1),
 			If(self.we & self.writable,
-				If(self.timestamp < counter + 2, self.underflow.eq(1))
+				If(self.timestamp[fine_ts_width:] < counter + 2, self.underflow.eq(1))
 			)
 		]
 
 		fifos = []
 		for n, channel in enumerate(channels):
 			fifo = SyncFIFOBuffered([
-				("timestamp", counter_width), ("value", 1)],
+				("timestamp", counter_width+fine_ts_width), ("value", 2)],
 				fifo_depth)
 			self.submodules += fifo
 			fifos.append(fifo)
@@ -39,30 +43,50 @@ class RTIOBankO(Module):
 			]
 
 			# FIFO read
-			time_hit = Signal()
 			self.comb += [
-				time_hit.eq(fifo.readable &
-					(fifo.dout.timestamp == counter)),
-				fifo.re.eq(time_hit)
+				channel.hit.eq(fifo.readable &
+					(fifo.dout.timestamp[fine_ts_width:] == counter)),
+				channel.value.eq(fifo.dout.value),
+				fifo.re.eq(channel.hit)
 			]
-			self.sync += If(time_hit, channel.eq(fifo.dout.value))
+			if fine_ts_width:
+				self.comb += channel.fine_ts.eq(fifo.dout.timestamp[:fine_ts_width])
 
 		selfifo = Array(fifos)[self.sel]
 		self.comb += self.writable.eq(selfifo.writable), self.level.eq(selfifo.level)
 
 class RTIO(Module, AutoCSR):
-	def __init__(self, channels, counter_width=32, ofifo_depth=8, ififo_depth=8):
-		self.submodules.bank_o = InsertReset(RTIOBankO(channels, counter_width, ofifo_depth))
+	def __init__(self, phy, counter_width=32, ofifo_depth=8, ififo_depth=8):
+		# Extract info from PHY
+		if hasattr(phy.interface[0], "o_fine_ts"):
+			fine_ts_width = flen(channels[0].o_fine_ts)
+		else:
+			fine_ts_width = 0
+		oes = [padif.oe for padif in phy.interface if hasattr(padif, "oe")]
 
+		# Submodules
+		self.submodules.bank_o = InsertReset(RTIOBankO(
+			[SimpleNamespace(hit=padif.o_set_value,
+					value=padif.o_value,
+					fine_ts=getattr(padif, "o_fine_ts", None))
+				for padif in phy.interface],
+			counter_width, fine_ts_width, ofifo_depth))
+
+		# CSRs
 		self._r_reset = CSRStorage(reset=1)
+		self._r_oe = CSRStorage(len(oes))
 		self._r_chan_sel = CSRStorage(flen(self.bank_o.sel))
-		self._r_o_timestamp = CSRStorage(counter_width)
+		self._r_o_timestamp = CSRStorage(counter_width+fine_ts_width)
 		self._r_o_value = CSRStorage()
 		self._r_o_writable = CSRStatus()
 		self._r_o_we = CSR()
 		self._r_o_underflow = CSRStatus()
 		self._r_o_level = CSRStatus(bits_for(ofifo_depth))
 
+		# OE
+		self.comb += Cat(*oes).eq(self._r_oe.storage)
+
+		# Output/Gate
 		self.comb += [
 			self.bank_o.reset.eq(self._r_reset.storage),
 			self.bank_o.sel.eq(self._r_chan_sel.storage),

soc/artiqlib/rtio/phy.py

@@ -0,0 +1,50 @@
+from migen.fhdl.std import *
+from migen.genlib.cdc import MultiReg
+from migen.genlib.record import Record
+
+class PHYBase(Module):
+	def __init__(self, fine_ts_bits, pads, output_only_pads):
+		self.interface = []
+		
+		for pad in pads:
+			layout = [
+				("o_set_value", 1),
+				("o_value", 1)
+			]
+			if fine_ts_bits:
+				layout.append(("o_fine_ts", fine_ts_bits))
+			if pad not in output_only_pads:
+				layout += [
+					("oe", 1),
+					("i_detect", 1),
+					("i_value", 1)
+				]
+				if fine_ts_bits:
+					layout.append(("i_fine_ts", fine_ts_bits))
+			self.interface.append(Record(layout))
+
+class SimplePHY(PHYBase):
+	def __init__(self, pads, output_only_pads=set()):
+		PHYBase.__init__(self, 0, pads, output_only_pads)
+
+		for pad, padif in zip(pads, self.interface):
+			o_pad_d1 = Signal()
+			o_pad = Signal()
+			self.sync += [
+				If(padif.o_set_value, o_pad_d1.eq(padif.o_value)),
+				o_pad.eq(o_pad_d1)
+			]
+			if pad in output_only_pads:
+				self.comb += pad.eq(o_pad)
+			else:
+				ts = TSTriple()
+				i_pad = Signal()
+				self.sync += ts.oe.eq(padif.oe)
+				self.comb += ts.o.eq(o_pad)
+				self.specials += MultiReg(ts.i, i_pad), \
+					ts.get_tristate(pad)
+
+				i_pad_d = Signal()
+				self.sync += i_pad_d.eq(i_pad)
+				self.comb += padif.i_detect.eq(i_pad ^ i_pad_d), \
+					padif.i_value.eq(i_pad)

soc/targets/artiq.py

@@ -122,8 +122,13 @@ class ARTIQSoC(SDRAMSoC):
 
 		self.submodules.leds = gpio.GPIOOut(Cat(platform.request("user_led", 0),
 			platform.request("user_led", 1)))
+
 		self.comb += platform.request("ttl_tx_en").eq(1)
-		self.submodules.rtio = rtio.RTIO([platform.request("ttl", i) for i in range(4)])
+		rtio_pads = [platform.request("ttl", i) for i in range(4)]
+		self.submodules.rtiophy = rtio.phy.SimplePHY(rtio_pads,
+			{rtio_pads[1], rtio_pads[2], rtio_pads[3]})
+		self.submodules.rtio = rtio.RTIO(self.rtiophy)
+
 		self.submodules.dds = ad9858.AD9858(platform.request("dds"))
 		self.add_wb_slave(lambda a: a[26:29] == 3, self.dds.bus)