wrpll: drive helper clock domain

artiq/firmware/libboard_artiq/wrpll.rs

@@ -1,3 +1,5 @@
+use board_misoc::{csr, clock};
+
 mod i2c {
     use board_misoc::{csr, clock};
 
@@ -272,6 +274,8 @@ mod si549 {
 pub fn init() {
     info!("initializing...");
 
+    unsafe { csr::wrpll::helper_reset_write(1); }
+
     #[cfg(rtio_frequency = "125.0")]
     let (m_hsdiv, m_lsdiv, m_fbdiv) = (0x017, 2, 0x04b5badb98a);
     #[cfg(rtio_frequency = "125.0")]
@@ -281,6 +285,9 @@ pub fn init() {
         .expect("cannot initialize main Si549");
     si549::program(i2c::Dcxo::Helper, h_hsdiv, h_lsdiv, h_fbdiv)
         .expect("cannot initialize helper Si549");
+
+    clock::spin_us(10_000); // Settling Time after FS Change
+    unsafe { csr::wrpll::helper_reset_write(0); }
 }
 
 pub fn select_recovered_clock(rc: bool) {

artiq/gateware/drtio/wrpll/core.py

@@ -1,10 +1,21 @@
 from migen import *
+from migen.genlib.resetsync import AsyncResetSynchronizer
 from misoc.interconnect.csr import *
 
 from artiq.gateware.drtio.wrpll.si549 import Si549
 
 
 class WRPLL(Module, AutoCSR):
-	def __init__(self, main_dcxo_i2c, helper_dxco_i2c):
+	def __init__(self, helper_clk_pads, main_dcxo_i2c, helper_dxco_i2c):
+		self.helper_reset = CSRStorage(reset=1)
+
+		self.clock_domains.cd_helper = ClockDomain()
+		self.helper_reset.storage.attr.add("no_retiming")
+		self.specials += [
+			Instance("IBUFGDS", i_I=helper_clk_pads.p, i_IB=helper_clk_pads.n,
+				o_O=self.cd_helper.clk),
+			AsyncResetSynchronizer(self.cd_helper, self.helper_reset.storage)
+		]
+
 		self.submodules.main_dcxo = Si549(main_dcxo_i2c)
 		self.submodules.helper_dcxo = Si549(helper_dxco_i2c)

artiq/gateware/targets/sayma_amc.py

@@ -137,6 +137,7 @@ class SatelliteBase(MiniSoC):
                 platform.request("ddmtd_helper_dcxo_oe").eq(1)
             ]
             self.submodules.wrpll = WRPLL(
+                helper_clk_pads=platform.request("ddmtd_helper_clk"),
                 main_dcxo_i2c=platform.request("ddmtd_main_dcxo_i2c"),
                 helper_dxco_i2c=platform.request("ddmtd_helper_dcxo_i2c"))
             self.csr_devices.append("wrpll")