From 03d3a85e75de14f982b0fc49037d51b78d3c3186 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Sat, 15 Oct 2016 18:36:27 +0800
Subject: [PATCH] drtio: RX clock alignment and ready

---
 artiq/gateware/drtio/core.py                  |  6 +++
 .../gateware/drtio/transceiver/gtx_7series.py | 10 ++++-
 .../drtio/transceiver/gtx_7series_init.py     | 38 ++++++++++++++-----
 3 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/artiq/gateware/drtio/core.py b/artiq/gateware/drtio/core.py
index 2c6c08fbe..98bb47960 100644
--- a/artiq/gateware/drtio/core.py
+++ b/artiq/gateware/drtio/core.py
@@ -9,6 +9,11 @@ class DRTIOSatellite(Module):
     def __init__(self, transceiver, rx_synchronizer, channels, fine_ts_width=3, full_ts_width=63):
         self.submodules.link_layer = link_layer.LinkLayer(
             transceiver.encoder, transceiver.decoders)
+        self.comb += [
+            transceiver.rx_reset.eq(self.link_layer.rx_reset),
+            self.link_layer.rx_ready.eq(transceiver.rx_ready)
+        ]
+
         link_layer_sync = SimpleNamespace(
             tx_aux_frame=self.link_layer.tx.aux_frame,
             tx_aux_data=self.link_layer.tx_aux_data,
@@ -24,6 +29,7 @@ class DRTIOSatellite(Module):
         )
         self.submodules.rt_packets = ClockDomainsRenamer("rtio")(
             rt_packets.RTPacketSatellite(link_layer_sync))
+
         self.submodules.iot = ClockDomainsRenamer("rtio")(
             iot.IOT(self.rt_packets, channels, fine_ts_width, full_ts_width))
 
diff --git a/artiq/gateware/drtio/transceiver/gtx_7series.py b/artiq/gateware/drtio/transceiver/gtx_7series.py
index d90aa0bcc..1c34359e3 100644
--- a/artiq/gateware/drtio/transceiver/gtx_7series.py
+++ b/artiq/gateware/drtio/transceiver/gtx_7series.py
@@ -164,7 +164,15 @@ class GTX_1000BASE_BX10(Module):
             self.decoders[0].input.eq(rxdata[:10]),
             self.decoders[1].input.eq(rxdata[10:])
         ]
-        # TODO: clock aligner, reset/ready
+
+        clock_aligner = BruteforceClockAligner(0b0011111000, 62.5e6)
+        self.submodules += clock_aligner
+        self.comb += [
+            clock_aligner.rxdata.eq(rxdata),
+            rx_init.restart.eq(clock_aligner.restart),
+            clock_aligner.reset.eq(self.rx_reset),
+            self.rx_ready.eq(clock_aligner.ready)
+        ]
 
 
 class RXSynchronizer(Module):
diff --git a/artiq/gateware/drtio/transceiver/gtx_7series_init.py b/artiq/gateware/drtio/transceiver/gtx_7series_init.py
index fa01c88f3..1c6fc5a9f 100644
--- a/artiq/gateware/drtio/transceiver/gtx_7series_init.py
+++ b/artiq/gateware/drtio/transceiver/gtx_7series_init.py
@@ -131,20 +131,25 @@ class GTXInit(Module):
 # Those design flaws make RXSLIDE_MODE=PMA yet another broken and useless
 # transceiver "feature".
 class BruteforceClockAligner(Module):
-    def __init__(self, comma, sys_clk_freq, check_period=6e-3):
+    def __init__(self, comma, rtio_clk_freq, check_period=6e-3, ready_time=50e-3):
         self.rxdata = Signal(20)
         self.restart = Signal()
 
-        check_max_val = ceil(check_period*sys_clk_freq)
+        self.reset = Signal()
+        self.ready = Signal()
+
+        check_max_val = ceil(check_period*rtio_clk_freq)
         check_counter = Signal(max=check_max_val+1)
         check = Signal()
-        self.sync += [
+        self.sync.rtio += [
             check.eq(0),
-            If(check_counter == 0,
-                check.eq(1),
-                check_counter.eq(check_max_val)
-            ).Else(
-                check_counter.eq(check_counter-1)
+            If(~self.ready,
+                If(check_counter == 0,
+                    check.eq(1),
+                    check_counter.eq(check_max_val)
+                ).Else(
+                    check_counter.eq(check_counter-1)
+                )
             )
         ]
 
@@ -154,7 +159,7 @@ class BruteforceClockAligner(Module):
         self.specials += MultiReg(comma_seen_rxclk, comma_seen)
         comma_seen_reset = PulseSynchronizer("sys", "rx")
         self.submodules += comma_seen_reset
-        self.sync.rx += \
+        self.sync.rtio_rx += \
             If(comma_seen_reset.o,
                 comma_seen_rxclk.eq(0)
             ).Elif((self.rxdata[:10] == comma) | (self.rxdata[:10] == comma_n),
@@ -166,3 +171,18 @@ class BruteforceClockAligner(Module):
                 If(~comma_seen, self.restart.eq(1)),
                 comma_seen_reset.i.eq(1)
             )
+
+        ready_counts = ceil(ready_time/check_period)
+        assert ready_counts > 1
+        ready_counter = Signal(max=ready_counts+1, reset=ready_counts)
+        self.sync.rtio += [
+            If(check,
+                If(comma_seen,
+                    If(ready_counter != 0, ready_counter.eq(ready_counter-1))
+                ).Else(
+                    ready_counter.eq(ready_counts)
+                )
+            ),
+            If(self.reset, ready_counter.eq(ready_counts))
+        ]
+        self.comb += self.ready.eq(ready_counter == 0)