phy: use common cs control for sdr and ddr

use common cs control for sdr and ddr

Signed-off-by: Fin Maaß <[email protected]>

litespi/common.py

@@ -7,6 +7,10 @@
 from migen import *
 from migen.genlib.cdc import MultiReg
 
+from litex.gen import *
+from litex.gen.genlib.misc import WaitTimer
+from litex.build.io import SDROutput
+
 # Core <-> PHY Layouts -----------------------------------------------------------------------------
 
 """
@@ -41,3 +45,21 @@ def __init__(self, src, dst, clock_domain):
             self.comb += dst.eq(src)
         else:
             self.specials += MultiReg(src, dst, clock_domain)
+
+# LiteSPI CS Control -------------------------------------------------------------------------------
+
+class LiteSPICSControl(LiteXModule):
+    def __init__(self, pads, cs, cs_delay):
+        self.enable = enable = Signal()
+        cs_n = Signal().like(pads.cs_n)
+
+        self.timer = timer  = WaitTimer(cs_delay + 1) # Ensure cs_delay cycles between XFers.
+
+        self.comb += timer.wait.eq(cs != 0)
+        self.comb += enable.eq(timer.done)
+        self.comb += cs_n.eq(~(Replicate(enable, len(pads.cs_n)) & self.cs))
+
+        self.specials += SDROutput(
+            i = cs_n,
+            o = pads.cs_n
+        )

litespi/phy/generic_ddr.py

@@ -73,16 +73,7 @@ def __init__(self, pads, flash, cs_delay, extra_latency=0):
         self.clkgen = clkgen = DDRLiteSPIClkGen(pads)
 
         # CS control.
-        self.cs_timer = cs_timer  = WaitTimer(cs_delay + 1) # Ensure cs_delay cycles between XFers.
-        cs_enable = Signal()
-        self.comb += cs_timer.wait.eq(self.cs != 0)
-        self.comb += cs_enable.eq(cs_timer.done)
-        cs_n = Signal().like(pads.cs_n)
-        self.comb += cs_n.eq(~(Replicate(cs_enable, len(pads.cs_n)) & self.cs))
-        self.specials += SDROutput(
-            i = cs_n,
-            o = pads.cs_n
-        )
+        self.cs_control = cs_control = LiteSPICSControl(pads, self.cs, cs_delay)
 
         dq_o  = Array([Signal(len(pads.dq)) for _ in range(2)])
         dq_i  = Array([Signal(len(pads.dq)) for _ in range(2)])
@@ -143,7 +134,7 @@ def __init__(self, pads, flash, cs_delay, extra_latency=0):
             # Stop Clk.
             NextValue(clkgen.en, 0),
             # Wait for CS and a CMD from the Core.
-            If(cs_enable & sink.valid,
+            If(cs_control.enable & sink.valid,
                 # Load Shift Register Count/Data Out.
                 NextValue(sr_cnt, sink.len - sink.width),
                 sr_out_load.eq(1),

litespi/phy/generic_sdr.py

@@ -92,16 +92,7 @@ def __init__(self, pads, flash, device, clock_domain, default_divisor, cs_delay)
         self.comb += clkgen.div.eq(spi_clk_divisor)
 
         # CS control.
-        self.cs_timer = cs_timer  = WaitTimer(cs_delay + 1) # Ensure cs_delay cycles between XFers.
-        cs_enable = Signal()
-        self.comb += cs_timer.wait.eq(self.cs != 0)
-        self.comb += cs_enable.eq(cs_timer.done)
-        cs_n = Signal().like(pads.cs_n)
-        self.comb += cs_n.eq(~(Replicate(cs_enable, len(pads.cs_n)) & self.cs))
-        self.specials += SDROutput(
-            i = cs_n,
-            o = pads.cs_n
-        )
+        self.cs_control = cs_control = LiteSPICSControl(pads, self.cs, cs_delay)
 
         if hasattr(pads, "mosi"):
             dq_o  = Signal()
@@ -165,7 +156,7 @@ def __init__(self, pads, flash, device, clock_domain, default_divisor, cs_delay)
         self.fsm = fsm = FSM(reset_state="WAIT-CMD-DATA")
         fsm.act("WAIT-CMD-DATA",
             # Wait for CS and a CMD from the Core.
-            If(cs_enable & sink.valid,
+            If(cs_control.enable & sink.valid,
                 # Load Shift Register Count/Data Out.
                 NextValue(sr_cnt, sink.len - sink.width),
                 NextValue(dq_oe, sink.mask),