From 353e7fc13b9beac1a619624ad416889dd5b0041f Mon Sep 17 00:00:00 2001
From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Tue, 4 Nov 2014 17:35:46 +0100
Subject: [PATCH] link: add SATALinkLayer skeleton (wip)

---
 lib/sata/link/__init__.py  | 83 ++++++++++++++++++++++++++++++++++++++
 lib/sata/link/crc.py       | 13 +++++-
 lib/sata/link/scrambler.py | 27 ++++++++++++-
 lib/sata/std.py            | 21 ++++++++++
 4 files changed, 142 insertions(+), 2 deletions(-)
 create mode 100644 lib/sata/link/__init__.py

diff --git a/lib/sata/link/__init__.py b/lib/sata/link/__init__.py
new file mode 100644
index 00000000..c864be83
--- /dev/null
+++ b/lib/sata/link/__init__.py
@@ -0,0 +1,83 @@
+from migen.fhdl.std import *
+
+from lib.sata.std import *
+from lib.sata.link import crc
+from lib.sata.link import scrambler
+
+class SATALinkLayerTX(Module):
+	def __init__(self, dw):
+		self.sink = Sink(link_layout(dw))
+		self.source = Source(phy_layout(dw))
+
+		###
+
+	# insert CRC
+		crc_inserter = crc.SATACRCInserter(link_layout(dw))
+		self.submodules += crc_inserter
+
+	# scramble
+		scrambler = scrambler.SATAScrambler(link_layout(dw))
+		self.submodules += scrambler
+
+class SATALinkLayerRX(Module):
+	def __init__(self, dw):
+		self.sink = Sink(link_layout(dw))
+		self.source = Source(phy_layout(dw))
+
+		###
+
+	# descramble
+		descrambler = descrambler.SATAScrambler(link_layout(dw))
+		self.submodules += descrambler
+
+	# check CRC
+		crc_checker = crc.SATACRCChecker(link_layout(dw))
+		self.submodules += crc_checker
+
+class SATALinkLayer(Module):
+	def __init__(self, phy, dw=32):
+		self.submodules.tx = SATALinkLayerTX(dw)
+		self.submodules.rx = SATALinkLayerRX(dw)
+
+		fsm = FSM(reset_state="IDLE")
+		self.submodules += fsm
+		fsm.act("IDLE",
+			phy.sink.stb.eq(1),
+			phy.sink.d.eq(SYNC_VAL),
+			NextState("RDY")
+		)
+		fsm.act("RDY",
+			phy.sink.stb.eq(1),
+			phy.sink.d.eq(X_RDY_VAL)
+			If(phy.source.stb & (phy.source.d == X_RDY_VAL),
+				NextState("SOF")
+		)
+		fsm.act("SOF",
+			phy.sink.stb.eq(1),
+			phy.sink.d.eq(SOF_VAL),
+			NextState("COPY")
+		)
+		fsm.act("COPY",
+			phy.sink.stb.eq(1),
+			phy.sink.d.eq(),
+			NextState("EOF")
+		)
+		fsm.act("EOF",
+			phy.sink.stb.eq(1),
+			phy.sink.d.eq(EOF_VAL),
+			NextState("")
+		)
+		fsm.act("EOF",
+			phy.sink.stb.eq(1),
+			phy.sink.d.eq(EOF_VAL),
+			NextState("")
+		)
+		fsm.act("WTRM",
+			phy.sink.stb.eq(1),
+			phy.sink.d.eq(WTRM_VAL),
+			If(phy.source.stb & (phy.source.d == R_OK_VAL),
+				NextState("IDLE")
+			).Elif(phy.source.stb & (phy.source.d == R_ERR_VAL),
+				NextState("IDLE")
+			)
+		)
diff --git a/lib/sata/link/crc.py b/lib/sata/link/crc.py
index 59c650a1..e7bb3bb0 100644
--- a/lib/sata/link/crc.py
+++ b/lib/sata/link/crc.py
@@ -1,5 +1,8 @@
 from migen.fhdl.std import *
 from migen.genlib.misc import optree
+from migen.actorlib.crc import CRCInserter, CRCChecker
+
+from lib.sata.std import *
 
 class CRCEngine(Module):
 	"""Cyclic Redundancy Check Engine
@@ -54,7 +57,7 @@ class CRCEngine(Module):
 		# compute and optimize CRC's LFSR
 		curval = [[("new", i)] for i in range(width)]
 		for i in range(width):
-			feedback = curval.pop()		
+			feedback = curval.pop()
 			for j in range(width-1):
 				if (polynom & (1<<(j+1))):
 					curval[j] += feedback
@@ -104,3 +107,11 @@ class SATACRC(Module):
 			self.value.eq(reg_i),
 			self.error.eq(self.engine.next != self.check)
 		]
+
+class SATACRCInserter(CRCInserter):
+	def __init__(self, layout):
+		CRCInserter.__init__(self, SATACRC, layout)
+
+class SATACRCChecker(CRCChecker):
+	def __init__(self, layout):
+		CRCChecker.__init__(self, SATACRC, layout)
\ No newline at end of file
diff --git a/lib/sata/link/scrambler.py b/lib/sata/link/scrambler.py
index e2aaa54b..8f301a19 100644
--- a/lib/sata/link/scrambler.py
+++ b/lib/sata/link/scrambler.py
@@ -3,7 +3,7 @@ from migen.genlib.misc import optree
 
 @DecorateModule(InsertReset)
 @DecorateModule(InsertCE)
-class SATAScrambler(Module):
+class Scrambler(Module):
 	"""SATA Scrambler
 
 	Implement a SATA Scrambler
@@ -65,3 +65,28 @@ class SATAScrambler(Module):
 			self.comb += next_value[n].eq(optree("^", eq))
 
 		self.comb += self.value.eq(next_value)
+
+class SATAScrambler(Module):
+	def __init__(self, layout):
+		self.sink = sink = Sink(layout)
+		self.source = source = Source(layout)
+
+		###
+
+		self.submodules.scrambler = Scrambler()
+		ongoing = Signal()
+		self.sync += [
+			If(sink.stb & sink.ack,
+				If(sink.eop,
+					ongoing.eq(0)
+				).Elsif(sink.sop,
+					ongoing.eq(1)
+				)
+			)
+		]
+		self.comb += [
+			self.scrambler.ce.eq(sink.stb & (sink.sop | ongoing)),
+			self.scrambler.reset.eq(~ongoing),
+			Record.connect(sink, source),
+			source.d.eq(sink.d ^ self.scrambler.value)
+		]
diff --git a/lib/sata/std.py b/lib/sata/std.py
index 3f3ea2f4..b2370c50 100644
--- a/lib/sata/std.py
+++ b/lib/sata/std.py
@@ -1,8 +1,29 @@
 from migen.fhdl.std import *
 
+ALIGN_VAL   = 0x7B4A4ABC
+SYNC_VAL    = 0xB5B5957C
+R_RDY_VAL   = 0x4A4A957C
+R_OK_VAL    = 0x3535B57C
+R_ERR_VAL   = 0x5656B57C
+R_IP_VAL    = 0X5555B57C
+X_RDY_VAL   = 0x5757B57C
+CONT_VAL    = 0x9999AA7C
+WTRM_VAL    = 0x5858B57C
+SOF_VAL     = 0x3737B57C
+EOF_VAL     = 0xD5D5B57C
+HOLD_VAL    = 0xD5D5AA7C
+HOLD_ACK    = 0X9595AA7C
+
 def phy_layout(dw):
 	layout = [
 		("p_packetized", True),
 		("d", dw)
 	]
 	return layout
+
+def link_layout(dw):
+	layout = [
+		("p_packetized", True),
+		("d", dw)
+	]
+	return layout
-- 
2.30.2