litex/lib/sata/k7sataphy/crg.py

from math import ceil

from migen.fhdl.std import *
from migen.genlib.resetsync import AsyncResetSynchronizer
from migen.genlib.fsm import FSM, NextState

from lib.sata.k7sataphy.std import *

class K7SATAPHYReconfig(Module):
	def __init__(self, channel_drp, mmcm_drp):
		self.speed = Signal(3)
		###
		speed_r = Signal(3)
		speed_change = Signal()
		self.sync += speed_r.eq(self.speed)
		self.comb += speed_change.eq(self.speed != speed_r)

		drp_sel = Signal()
		drp = DRPBus()
		self.comb += \
			If(drp_sel,
				drp.connect(mmcm_drp)
			).Else(
				drp.connect(channel_drp)
			)

class K7SATAPHYCRG(Module):
	def __init__(self, pads, gtx, clk_freq, default_speed):
		self.reset = Signal()
		self.ready = Signal()

		self.clock_domains.cd_sata_tx = ClockDomain()
		self.clock_domains.cd_sata_rx = ClockDomain()

	# CPLL
		# (SATA3) 150MHz / VCO @ 3GHz / Line rate @ 6Gbps
		# (SATA2 & SATA1) VCO still @ 3 GHz, Line rate is decreased with output divivers.
		# When changing rate, reconfiguration of the CPLL over DRP is needed to:
		#  - update the output divider
		#  - update the equalizer configuration (specific for each line rate).
		refclk = Signal()
		self.specials += Instance("IBUFDS_GTE2",
			i_CEB=0,
			i_I=pads.refclk_p,
			i_IB=pads.refclk_n,
			o_O=refclk
		)
		self.comb += gtx.gtrefclk0.eq(refclk)

	# TX clocking
		# (SATA3) 150MHz from CPLL TXOUTCLK, sata_tx clk @ 300MHz (16-bits)
		# (SATA2) 150MHz from CPLL TXOUTCLK, sata_tx clk @ 150MHz (16-bits)
		# (SATA1) 150MHz from CPLL TXOUTCLK, sata_tx clk @ 75MHz (16-bits)
		# When changing rate, reconfiguration of the MMCM is needed to update the output divider.		
		mmcm_reset = Signal()
		mmcm_locked = Signal()
		mmcm_drp = DRPBus()
		mmcm_fb = Signal()
		mmcm_clk_i = Signal()
		mmcm_clk0_o = Signal()
		mmcm_clk1_o = Signal()
		mmcm_div_config = {
			"SATA1" : 	16,
			"SATA2" :	8,
			"SATA3" : 	4
			}
		mmcm_div = mmcm_div_config[default_speed]
		self.specials += [
			Instance("BUFG", i_I=gtx.txoutclk, o_O=mmcm_clk_i),
			Instance("MMCME2_ADV",
				p_BANDWIDTH="HIGH", p_COMPENSATION="ZHOLD", i_RST=mmcm_reset, o_LOCKED=mmcm_locked,

				# DRP
				i_DCLK=mmcm_drp.clk, i_DEN=mmcm_drp.en, o_DRDY=mmcm_drp.rdy, i_DWE=mmcm_drp.we,
				i_DADDR=mmcm_drp.addr, i_DI=mmcm_drp.di, o_DO=mmcm_drp.do,

				# VCO
				p_REF_JITTER1=0.01, p_CLKIN1_PERIOD=6.666,
				p_CLKFBOUT_MULT_F=8.000, p_CLKFBOUT_PHASE=0.000, p_DIVCLK_DIVIDE=1,
				i_CLKIN1=mmcm_clk_i, i_CLKFBIN=mmcm_fb, o_CLKFBOUT=mmcm_fb,

				# CLK0
				p_CLKOUT0_DIVIDE_F=mmcm_div, p_CLKOUT0_PHASE=0.000, o_CLKOUT0=mmcm_clk0_o,

				# CLK1
				p_CLKOUT1_DIVIDE=mmcm_div*2, p_CLKOUT1_PHASE=0.000, o_CLKOUT1=mmcm_clk1_o,
			),
			Instance("BUFG", i_I=mmcm_clk0_o, o_O=self.cd_sata_tx.clk),
		]
		self.comb += [
			gtx.txusrclk.eq(self.cd_sata_tx.clk),
			gtx.txusrclk2.eq(self.cd_sata_tx.clk)
		]

	# RX clocking
		# (SATA3) sata_rx recovered clk @ 300MHz from CPLL RXOUTCLK
		# (SATA2) sata_rx recovered clk @ 150MHz from CPLL RXOUTCLK
		# (SATA1) sata_rx recovered clk @ 150MHz from CPLL RXOUTCLK		
		self.specials += [
			Instance("BUFG", i_I=gtx.rxoutclk, o_O=self.cd_sata_rx.clk),
		]
		self.comb += [
			gtx.rxusrclk.eq(self.cd_sata_rx.clk),
			gtx.rxusrclk2.eq(self.cd_sata_rx.clk)
		]

	# Bypass TX buffer
		self.comb += [
			gtx.txphdlyreset.eq(0),
			gtx.txphalignen.eq(0),
			gtx.txdlyen.eq(0),
			gtx.txphalign.eq(0),
			gtx.txphinit.eq(0)
		]

	# Bypass RX buffer
		self.comb += [
			gtx.rxphdlyreset.eq(0),
			gtx.rxdlyen.eq(0),
			gtx.rxphalign.eq(0),
			gtx.rxphalignen.eq(0),
		]

	# Configuration Reset
		# After configuration, GTX resets have to stay low for at least 500ns
		# See AR43482
		reset_en = Signal()
		clk_period_ns = 1000000000/clk_freq
		reset_en_cnt_max = ceil(500/clk_period_ns)
		reset_en_cnt = Signal(max=reset_en_cnt_max, reset=reset_en_cnt_max-1)
		self.sync += If(~reset_en, reset_en_cnt.eq(reset_en_cnt-1))
		self.comb += reset_en.eq(reset_en_cnt == 0)

	# TX Reset FSM
		tx_reset_fsm = FSM(reset_state="IDLE")
		self.submodules += tx_reset_fsm
		tx_reset_fsm.act("IDLE",
			gtx.txuserrdy.eq(0),
			gtx.gttxreset.eq(0),
			gtx.txdlysreset.eq(0),
			If(reset_en,
				NextState("RESET_ALL"),
			)
		)
		tx_reset_fsm.act("RESET_ALL",
			gtx.txuserrdy.eq(0),
			gtx.gttxreset.eq(1),
			gtx.txdlysreset.eq(1),
			If(gtx.cplllock & mmcm_locked,
				NextState("RELEASE_GTXRESET")
			)
		)
		tx_reset_fsm.act("RELEASE_GTXRESET",
			gtx.txuserrdy.eq(1),
			gtx.gttxreset.eq(0),
			gtx.txdlysreset.eq(1),
			If(self.reset,
				NextState("RESET_ALL")
			).Elif(gtx.txresetdone,
				NextState("RELEASE_DLYRESET")
			)
		)
		tx_reset_fsm.act("RELEASE_DLYRESET",
			gtx.txuserrdy.eq(1),
			gtx.gttxreset.eq(0),
			gtx.txdlysreset.eq(0),
			If(self.reset,
				NextState("RESET_ALL")
			).Elif(gtx.txdlysresetdone,
				NextState("READY")
			)
		)
		tx_reset_fsm.act("READY",
			gtx.txuserrdy.eq(1),
			gtx.gttxreset.eq(0),
			gtx.txdlysreset.eq(0),
			If(self.reset,
				NextState("RESET_ALL")
			)
		)

	# RX Reset FSM
		rx_reset_fsm = FSM(reset_state="IDLE")
		self.submodules += rx_reset_fsm
		rx_reset_fsm.act("IDLE",
			gtx.rxuserrdy.eq(0),
			gtx.gtrxreset.eq(0),
			gtx.rxdlysreset.eq(0),
			If(reset_en,
				NextState("RESET_ALL"),
			)
		)
		rx_reset_fsm.act("RESET_ALL",
			gtx.rxuserrdy.eq(0),
			gtx.gtrxreset.eq(1),
			gtx.rxdlysreset.eq(1),
			If(gtx.cplllock & mmcm_locked,
				NextState("RELEASE_GTXRESET")
			)
		)
		rx_reset_fsm.act("RELEASE_GTXRESET",
			gtx.rxuserrdy.eq(1),
			gtx.gtrxreset.eq(0),
			gtx.rxdlysreset.eq(1),
			If(self.reset,
				NextState("RESET_ALL")
			).Elif(gtx.rxresetdone,
				NextState("RELEASE_DLYRESET")
			)
		)
		rx_reset_fsm.act("RELEASE_DLYRESET",
			gtx.rxuserrdy.eq(1),
			gtx.gtrxreset.eq(0),
			gtx.rxdlysreset.eq(0),
			If(self.reset,
				NextState("RESET_ALL")
			).Elif(gtx.rxdlysresetdone,
				NextState("READY")
			)
		)
		rx_reset_fsm.act("READY",
			gtx.rxuserrdy.eq(1),
			gtx.gtrxreset.eq(0),
			gtx.rxdlysreset.eq(0),
			If(self.reset,
				NextState("RESET_ALL")
			)
		)

		self.comb += self.ready.eq(tx_reset_fsm.ongoing("READY") & rx_reset_fsm.ongoing("READY"))

	# Reset PLL
		self.comb += gtx.cpllreset.eq(self.reset | ~reset_en)

	# Reset for SATA TX/RX clock domains
		self.specials += [
			AsyncResetSynchronizer(self.cd_sata_tx, ~self.ready),
			AsyncResetSynchronizer(self.cd_sata_rx, ~self.ready),
		]

	# Dynamic Reconfiguration
		self.submodules.reconfig = K7SATAPHYReconfig(mmcm_drp, gtx.drp)