asmicon: refresher (untested)

m-labs · Mar 15, 2012 · 7c37788 · 7c37788
1 parent e3ef121
commit 7c37788
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Showing 4 changed files with 101 additions and 14 deletions.
diff --git a/milkymist/asmicon/__init__.py b/milkymist/asmicon/__init__.py
@@ -6,21 +6,23 @@
 from milkymist.asmicon.multiplexer import *
 
 class PhySettings:
-	def __init__(self, dfi_a, dfi_ba, dfi_d, nphases, rdphase, wrphase):
+	def __init__(self, dfi_a, dfi_d, nphases, rdphase, wrphase):
+		# NB: dfi_ba is obtained from GeomSettings.bank_a
 		self.dfi_a = dfi_a
-		self.dfi_ba = dfi_ba
 		self.dfi_d = dfi_d
 		self.nphases = nphases
 		self.rdphase = rdphase
 		self.wrphase = wrphase
 
 class GeomSettings:
-	def __init__(self, row_a, col_a):
+	def __init__(self, bank_a, row_a, col_a):
+		self.bank_a = bank_a
 		self.row_a = row_a
 		self.col_a = col_a
 
 class TimingSettings:
-	def __init__(self, tREFI, tRFC):
+	def __init__(self, tRP, tREFI, tRFC):
+		self.tRP = tRP
 		self.tREFI = tREFI
 		self.tRFC = tRFC
 
@@ -32,12 +34,12 @@ def __init__(self, phy_settings, geom_settings, timing_settings, time=0):
 		self.finalized = False
 
 		self.dfi = dfi.Interface(self.phy_settings.dfi_a,
-			self.phy_settings.dfi_ba,
+			self.geom_settings.bank_a,
 			self.phy_settings.dfi_d,
 			self.phy_settings.nphases)
 		burst_length = self.phy_settings.nphases*2
 		self.address_align = log2_int(burst_length)
-		aw = self.phy_settings.dfi_ba + self.geom_settings.row_a + self.geom_settings.col_a - self.address_align
+		aw = self.geom_settings.bank_a + self.geom_settings.row_a + self.geom_settings.col_a - self.address_align
 		dw = self.phy_settings.dfi_d*self.phy_settings.nphases
 		self.hub = asmibus.Hub(aw, dw, time)
 
@@ -47,8 +49,9 @@ def finalize(self):
 		self.finalized = True
 		self.hub.finalize()
 		slots = self.hub.get_slots()
-		self.refresher = Refresher(self.timing_settings)
-		self.bank_machines = [BankMachine(self.geom_settings, self.timing_settings, self.address_align, i, slots) for i in range(2**self.phy_settings.dfi_ba)]
+		self.refresher = Refresher(self.phy_settings.dfi_a, self.geom_settings.bank_a,
+			self.timing_settings.tRP, self.timing_settings.tREFI, self.timing_settings.tRFC)
+		self.bank_machines = [BankMachine(self.geom_settings, self.timing_settings, self.address_align, i, slots) for i in range(2**self.geom_settings.bank_a)]
 		self.multiplexer = Multiplexer(self.phy_settings, self.geom_settings, self.timing_settings,
 			self.bank_machines, self.refresher,
 			self.dfi, self.hub)

diff --git a/milkymist/asmicon/multiplexer.py b/milkymist/asmicon/multiplexer.py
@@ -1,5 +1,22 @@
 from migen.fhdl.structure import *
 
+class CommandRequest:
+	def __init__(self, dfi_a, dfi_ba):
+		self.a = Signal(BV(dfi_a))
+		self.ba = Signal(BV(dfi_ba))
+		self.cas_n = Signal(reset=1)
+		self.ras_n = Signal(reset=1)
+		self.we_n = Signal(reset=1)
+
+class CommandRequestRW(CommandRequest):
+	def __init__(self, dfi_a, dfi_ba, tagbits):
+		CommandRequest.__init__(self, dfi_a, dfi_ba)
+		self.stb = Signal()
+		self.ack = Signal()
+		self.is_read = Signal()
+		self.is_write = Signal()
+		self.tag = Signal(BV(tagbits))
+
 class Multiplexer:
 	def __init__(self, phy_settings, geom_settings, timing_settings, bank_machines, refresher, dfi, hub):
 		pass

diff --git a/milkymist/asmicon/refresher.py b/milkymist/asmicon/refresher.py
@@ -1,8 +1,74 @@
 from migen.fhdl.structure import *
+from migen.corelogic.misc import timeline
+from migen.corelogic.fsm import FSM
+
+from milkymist.asmicon.multiplexer import *
 
 class Refresher:
-	def __init__(self, timing_settings):
-		pass
+	def __init__(self, dfi_a, dfi_ba, tRP, tREFI, tRFC):
+		self.tRP = tRP
+		self.tREFI = tREFI
+		self.tRFC = tRFC
+
+		self.req = Signal()
+		self.ack = Signal()
+		self.cmd_request = CommandRequest(dfi_a, dfi_ba)
 
 	def get_fragment(self):
-		return Fragment()
+		comb = []
+		sync = []
+
+		# Refresh sequence generator:
+		# PRECHARGE ALL --(tRP)--> AUTO REFRESH --(tRFC)--> done
+		seq_start = Signal()
+		seq_done = Signal()
+		sync += [
+			self.cmd_request.a.eq(2**10),
+			self.cmd_request.ba.eq(0),
+			self.cmd_request.cas_n.eq(1),
+			self.cmd_request.ras_n.eq(1),
+			self.cmd_request.we_n.eq(1)
+		]
+		sync += timeline(seq_start, [
+			(0, [
+				self.cmd_request.ras_n.eq(0),
+				self.cmd_request.we_n.eq(0)
+			]),
+			(self.tRP, [
+				self.cmd_request.cas_n.eq(0),
+				self.cmd_request.ras_n.eq(0)
+			]),
+			(self.tRP+self.tRFC, [
+				seq_done.eq(1)
+			])
+		])
+
+		# Periodic refresh counter
+		counter = Signal(BV(bits_for(self.tREFI - 1)))
+		start = Signal()
+		sync += [
+			start.eq(0),
+			If(counter == 0,
+				start.eq(1),
+				counter.eq(self.tREFI - 1)
+			).Else(
+				counter.eq(counter - 1)
+			)
+		]
+
+		# Control FSM
+		fsm = FSM("IDLE", "WAIT_GRANT", "WAIT_SEQ")
+		fsm.act(fsm.IDLE, If(start, fsm.next_state(fsm.WAIT_GRANT)))
+		fsm.act(fsm.WAIT_GRANT,
+			self.req.eq(1),
+			If(self.ack,
+				seq_start.eq(1),
+				fsm.next_state(fsm.WAIT_SEQ)
+			)
+		)
+		fsm.act(fsm.WAIT_SEQ,
+			self.req.eq(1),
+			If(seq_done, fsm.next_state(fsm.IDLE))
+		)
+
+		return Fragment(comb, sync) + fsm.get_fragment()
diff --git a/top.py b/top.py
@@ -21,17 +21,18 @@ def ns(t, margin=False):
 
 sdram_phy = asmicon.PhySettings(
 	dfi_a=13,
-	dfi_ba=2,
 	dfi_d=64, 
 	nphases=2,
 	rdphase=0,
 	wrphase=1
 )
 sdram_geom = asmicon.GeomSettings(
+	bank_a=2,
 	row_a=13,
 	col_a=10
 )
 sdram_timing = asmicon.TimingSettings(
+	tRP=ns(15),
 	tREFI=ns(7800),
 	tRFC=ns(70)
 )
@@ -58,8 +59,8 @@ def get():
 	#
 	# DFI
 	#
-	ddrphy0 = s6ddrphy.S6DDRPHY(sdram_phy.dfi_a, sdram_phy.dfi_ba, sdram_phy.dfi_d)
-	dfii0 = dfii.DFIInjector(1, sdram_phy.dfi_a, sdram_phy.dfi_ba, sdram_phy.dfi_d, sdram_phy.nphases)
+	ddrphy0 = s6ddrphy.S6DDRPHY(sdram_phy.dfi_a, sdram_geom.bank_a, sdram_phy.dfi_d)
+	dfii0 = dfii.DFIInjector(1, sdram_phy.dfi_a, sdram_geom.bank_a, sdram_phy.dfi_d, sdram_phy.nphases)
 	dficon0 = dfi.Interconnect(dfii0.master, ddrphy0.dfi)
 	dficon1 = dfi.Interconnect(asmicon0.dfi, dfii0.slave)