suservo: support operating with one urukul

implemented by wiring up the second Urukul to dummy pins

Signed-off-by: Robert Jördens <rj@quartiq.de>

artiq/gateware/eem.py

@@ -470,13 +470,15 @@ class Grabber(_EEM):
 class SUServo(_EEM):
     @staticmethod
     def io(*eems, iostandard="LVDS_25"):
-        assert len(eems) == 6
-        return (Sampler.io(*eems[0:2], iostandard=iostandard)
-                + Urukul.io_qspi(*eems[2:4], iostandard=iostandard)
-                + Urukul.io_qspi(*eems[4:6], iostandard=iostandard))
+        assert len(eems) in (4, 6)
+        io = (Sampler.io(*eems[0:2], iostandard=iostandard)
+                + Urukul.io_qspi(*eems[2:4], iostandard=iostandard))
+        if len(eems) == 6:  # two Urukuls
+            io += Urukul.io_qspi(*eems[4:6], iostandard=iostandard),
+        return io
 
     @classmethod
-    def add_std(cls, target, eems_sampler, eems_urukul0, eems_urukul1,
+    def add_std(cls, target, eems_sampler, eems_urukul,
                 t_rtt=4, clk=1, shift=11, profile=5,
                 iostandard="LVDS_25"):
         """Add a 8-channel Sampler-Urukul Servo
@@ -496,15 +498,14 @@ class SUServo(_EEM):
             (default: 5)
         """
         cls.add_extension(
-            target, *(eems_sampler + eems_urukul0 + eems_urukul1),
+            target, *(eems_sampler + sum(eems_urukul, [])),
             iostandard=iostandard)
         eem_sampler = "sampler{}".format(eems_sampler[0])
-        eem_urukul0 = "urukul{}".format(eems_urukul0[0])
-        eem_urukul1 = "urukul{}".format(eems_urukul1[0])
+        eem_urukul = ["urukul{}".format(i[0]) for i in eems_urukul]
 
         sampler_pads = servo_pads.SamplerPads(target.platform, eem_sampler)
         urukul_pads = servo_pads.UrukulPads(
-            target.platform, eem_urukul0, eem_urukul1)
+            target.platform, *eem_urukul)
         target.submodules += sampler_pads, urukul_pads
         # timings in units of RTIO coarse period
         adc_p = servo.ADCParams(width=16, channels=8, lanes=4, t_cnvh=4,
@@ -536,30 +537,24 @@ class SUServo(_EEM):
         target.submodules += phy
         target.rtio_channels.append(rtio.Channel.from_phy(phy, ififo_depth=4))
 
-        phy = spi2.SPIMaster(
-            target.platform.request("{}_spi_p".format(eem_urukul0)),
-            target.platform.request("{}_spi_n".format(eem_urukul0)))
-        target.submodules += phy
-        target.rtio_channels.append(rtio.Channel.from_phy(phy, ififo_depth=4))
+        for i in range(2):
+            if len(eem_urukul) > i:
+                spi_p, spi_n = (
+                    target.platform.request("{}_spi_p".format(eem_urukul[i])),
+                    target.platform.request("{}_spi_n".format(eem_urukul[i])))
+            else:  # create a dummy bus
+                spi_p = Record([("clk", 1), ("cs_n", 1)])  # mosi, cs_n
+                spi_n = None
 
-        pads = target.platform.request("{}_dds_reset_sync_in".format(eem_urukul0))
-        target.specials += DifferentialOutput(0, pads.p, pads.n)
+            phy = spi2.SPIMaster(spi_p, spi_n)
+            target.submodules += phy
+            target.rtio_channels.append(rtio.Channel.from_phy(phy, ififo_depth=4))
 
-        for i, signal in enumerate("sw0 sw1 sw2 sw3".split()):
-            pads = target.platform.request("{}_{}".format(eem_urukul0, signal))
-            target.specials += DifferentialOutput(
-                su.iir.ctrl[i].en_out, pads.p, pads.n)
+        for j, eem_urukuli in enumerate(eem_urukul):
+            pads = target.platform.request("{}_dds_reset_sync_in".format(eem_urukuli))
+            target.specials += DifferentialOutput(0, pads.p, pads.n)
 
-        phy = spi2.SPIMaster(
-            target.platform.request("{}_spi_p".format(eem_urukul1)),
-            target.platform.request("{}_spi_n".format(eem_urukul1)))
-        target.submodules += phy
-        target.rtio_channels.append(rtio.Channel.from_phy(phy, ififo_depth=4))
-
-        pads = target.platform.request("{}_dds_reset_sync_in".format(eem_urukul1))
-        target.specials += DifferentialOutput(0, pads.p, pads.n)
-
-        for i, signal in enumerate("sw0 sw1 sw2 sw3".split()):
-            pads = target.platform.request("{}_{}".format(eem_urukul1, signal))
-            target.specials += DifferentialOutput(
-                su.iir.ctrl[i + 4].en_out, pads.p, pads.n)
+            for i, signal in enumerate("sw0 sw1 sw2 sw3".split()):
+                pads = target.platform.request("{}_{}".format(eem_urukuli, signal))
+                target.specials += DifferentialOutput(
+                    su.iir.ctrl[j*4 + i].en_out, pads.p, pads.n)

artiq/gateware/suservo/pads.py

@@ -58,12 +58,12 @@ class SamplerPads(Module):
 
 
 class UrukulPads(Module):
-    def __init__(self, platform, eem0, eem1):
+    def __init__(self, platform, *eems):
         spip, spin = [[
                 platform.request("{}_qspi_{}".format(eem, pol), 0)
-                for eem in (eem0, eem1)] for pol in "pn"]
+                for eem in eems] for pol in "pn"]
         ioup = [platform.request("{}_io_update".format(eem), 0)
-                for eem in (eem0, eem1)]
+                for eem in eems]
         self.cs_n = Signal()
         self.clk = Signal()
         self.io_update = Signal()
@@ -71,12 +71,13 @@ class UrukulPads(Module):
                 DifferentialOutput(~self.cs_n, spip[i].cs, spin[i].cs),
                 DifferentialOutput(self.clk, spip[i].clk, spin[i].clk),
                 DifferentialOutput(self.io_update, ioup[i].p, ioup[i].n))
-                for i in range(2)]
+                for i in range(len(eems))]
         for i in range(8):
             mosi = Signal()
             setattr(self, "mosi{}".format(i), mosi)
+        for i in range(4*len(eems)):
             self.specials += [
-                DifferentialOutput(mosi,
+                DifferentialOutput(getattr(self, "mosi{}".format(i)),
                     getattr(spip[i // 4], "mosi{}".format(i % 4)),
                     getattr(spin[i // 4], "mosi{}".format(i % 4)))
             ]

artiq/gateware/targets/kasli_generic.py

@@ -64,13 +64,17 @@ def peripheral_sampler(module, peripheral):
 def peripheral_suservo(module, peripheral):
     if len(peripheral["sampler_ports"]) != 2:
         raise ValueError("wrong number of Sampler ports")
+    urukul_ports = []
     if len(peripheral["urukul0_ports"]) != 2:
         raise ValueError("wrong number of Urukul #0 ports")
-    if len(peripheral["urukul1_ports"]) != 2:
-        raise ValueError("wrong number of Urukul #1 ports")
+    urukul_ports.append(peripheral["urukul0_ports"])
+    if "urukul1_ports" in peripheral:
+        if len(peripheral["urukul1_ports"]) != 2:
+            raise ValueError("wrong number of Urukul #1 ports")
+        urukul_ports.append(peripheral["urukul1_ports"])
     eem.SUServo.add_std(module,
         peripheral["sampler_ports"],
-        peripheral["urukul0_ports"], peripheral["urukul1_ports"])
+        urukul_ports)
 
 
 def peripheral_zotino(module, peripheral):