Hardware
/
litedram
mirror of https://github.com/enjoy-digital/litedram.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

phy/ecp5: simplify/fix dqs_oe/dq_oe and revert BitSlip on dq_i_data. 

dq/dqs_oe was one cycle of and BitSlip on dq_i_data is required for correct initialization.
This commit is contained in:
Florent Kermarrec 2020-06-29 16:05:25 +02:00
parent 8c112c709c
commit fa7d91a053
1 changed files with 46 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

100
litedram/phy/ecp5ddrphy.py
View File

@ -130,7 +130,7 @@ class ECP5DDRPHY(Module, AutoCSR):
wrcmdphase = wrcmdphase, wrcmdphase = wrcmdphase,
cl = cl, cl = cl,
cwl = cwl, cwl = cwl,
read_latency = 2 + cl_sys_latency + 2 + log2_int(4//nphases) + 4, read_latency = 2 + cl_sys_latency + 2 + log2_int(4//nphases) + 5,
write_latency = cwl_sys_latency write_latency = cwl_sys_latency
) )
@ -140,7 +140,6 @@ class ECP5DDRPHY(Module, AutoCSR):
# # # # # #
bl8_chunk = Signal() bl8_chunk = Signal()
rddata_en = Signal(self.settings.read_latency)
# Iterate on pads groups ------------------------------------------------------------------- # Iterate on pads groups -------------------------------------------------------------------
for pads_group in range(len(pads.groups)): for pads_group in range(len(pads.groups)):
@ -202,10 +201,11 @@ class ECP5DDRPHY(Module, AutoCSR):
) )
# DQ --------------------------------------------------------------------------------------- # DQ ---------------------------------------------------------------------------------------
dq_oe = Signal() dq_oe = Signal()
dqs_oe = Signal() dqs_re = Signal()
dqs_pattern = DQSPattern() dqs_oe = Signal()
self.submodules += dqs_pattern dqs_postamble = Signal()
dqs_preamble = Signal()
for i in range(databits//8): for i in range(databits//8):
# DQSBUFM # DQSBUFM
dqs_i = Signal() dqs_i = Signal()
@ -225,21 +225,6 @@ class ECP5DDRPHY(Module, AutoCSR):
) )
datavalid = Signal() datavalid = Signal()
burstdet = Signal() burstdet = Signal()
dqs_read = Signal()
dqs_bitslip = Signal(2)
self.sync += [
If(self._dly_sel.storage[i],
If(self._rdly_dq_bitslip_rst.re,
dqs_bitslip.eq(0)
).Elif(self._rdly_dq_bitslip.re,
dqs_bitslip.eq(dqs_bitslip + 1)
)
)
]
dqs_cases = {}
for j, b in enumerate(range(-2, 2)):
dqs_cases[j] = dqs_read.eq(rddata_en[cl_sys_latency + b:cl_sys_latency + b + 2] != 0)
self.sync += Case(dqs_bitslip, dqs_cases)
self.specials += Instance("DQSBUFM", self.specials += Instance("DQSBUFM",
p_DQS_LI_DEL_ADJ = "MINUS", p_DQS_LI_DEL_ADJ = "MINUS",
p_DQS_LI_DEL_VAL = 1, p_DQS_LI_DEL_VAL = 1,
@ -262,8 +247,8 @@ class ECP5DDRPHY(Module, AutoCSR):
i_WRDIRECTION = 1, i_WRDIRECTION = 1,
# Reads (generate shifted DQS clock for reads) # Reads (generate shifted DQS clock for reads)
i_READ0 = dqs_read, i_READ0 = dqs_re,
i_READ1 = dqs_read, i_READ1 = dqs_re,
i_READCLKSEL0 = rdly[0], i_READCLKSEL0 = rdly[0],
i_READCLKSEL1 = rdly[1], i_READCLKSEL1 = rdly[1],
i_READCLKSEL2 = rdly[2], i_READCLKSEL2 = rdly[2],
@ -308,7 +293,7 @@ class ECP5DDRPHY(Module, AutoCSR):
dm_bl8_cases = {} dm_bl8_cases = {}
dm_bl8_cases[0] = dm_o_data_muxed.eq(dm_o_data[:4]) dm_bl8_cases[0] = dm_o_data_muxed.eq(dm_o_data[:4])
dm_bl8_cases[1] = dm_o_data_muxed.eq(dm_o_data_d[4:]) dm_bl8_cases[1] = dm_o_data_muxed.eq(dm_o_data_d[4:])
self.sync += Case(bl8_chunk, dm_bl8_cases) # FIXME: use self.comb? self.sync += Case(bl8_chunk, dm_bl8_cases)
self.specials += Instance("ODDRX2DQA", self.specials += Instance("ODDRX2DQA",
i_RST = ResetSignal("sys2x"), i_RST = ResetSignal("sys2x"),
i_ECLK = ClockSignal("sys2x"), i_ECLK = ClockSignal("sys2x"),
@ -329,10 +314,10 @@ class ECP5DDRPHY(Module, AutoCSR):
i_ECLK = ClockSignal("sys2x"), i_ECLK = ClockSignal("sys2x"),
i_SCLK = ClockSignal(), i_SCLK = ClockSignal(),
i_DQSW = dqsw, i_DQSW = dqsw,
i_D0 = 0, # FIXME: dqs_pattern.o[3], i_D0 = 0,
i_D1 = 1, # FIXME: dqs_pattern.o[2], i_D1 = 1,
i_D2 = 0, # FIXME: dqs_pattern.o[1], i_D2 = 0,
i_D3 = 1, # FIXME: dqs_pattern.o[0], i_D3 = 1,
o_Q = dqs o_Q = dqs
), ),
Instance("TSHX2DQSA", Instance("TSHX2DQSA",
@ -340,8 +325,8 @@ class ECP5DDRPHY(Module, AutoCSR):
i_ECLK = ClockSignal("sys2x"), i_ECLK = ClockSignal("sys2x"),
i_SCLK = ClockSignal(), i_SCLK = ClockSignal(),
i_DQSW = dqsw, i_DQSW = dqsw,
i_T0 = ~(dqs_pattern.preamble | dqs_oe | dqs_pattern.postamble), i_T0 = ~(dqs_oe | dqs_postamble),
i_T1 = ~(dqs_pattern.preamble | dqs_oe | dqs_pattern.postamble), i_T1 = ~(dqs_oe | dqs_preamble),
o_Q = dqs_oe_n o_Q = dqs_oe_n
), ),
Tristate(pads.dqs_p[i], dqs, ~dqs_oe_n, dqs_i) Tristate(pads.dqs_p[i], dqs, ~dqs_oe_n, dqs_i)
@ -352,7 +337,7 @@ class ECP5DDRPHY(Module, AutoCSR):
dq_i = Signal() dq_i = Signal()
dq_oe_n = Signal() dq_oe_n = Signal()
dq_i_delayed = Signal() dq_i_delayed = Signal()
dq_i_data = Signal(8) dq_i_data = Signal(4)
dq_o_data = Signal(8) dq_o_data = Signal(8)
dq_o_data_d = Signal(8) dq_o_data_d = Signal(8)
dq_o_data_muxed = Signal(4) dq_o_data_muxed = Signal(4)
@ -371,8 +356,7 @@ class ECP5DDRPHY(Module, AutoCSR):
dq_bl8_cases = {} dq_bl8_cases = {}
dq_bl8_cases[0] = dq_o_data_muxed.eq(dq_o_data[:4]) dq_bl8_cases[0] = dq_o_data_muxed.eq(dq_o_data[:4])
dq_bl8_cases[1] = dq_o_data_muxed.eq(dq_o_data_d[4:]) dq_bl8_cases[1] = dq_o_data_muxed.eq(dq_o_data_d[4:])
self.sync += Case(bl8_chunk, dq_bl8_cases) # FIXME: use self.comb? self.sync += Case(bl8_chunk, dq_bl8_cases)
_dq_i_data = Signal(4)
self.specials += [ self.specials += [
Instance("ODDRX2DQA", Instance("ODDRX2DQA",
i_RST = ResetSignal("sys2x"), i_RST = ResetSignal("sys2x"),
@ -405,23 +389,29 @@ class ECP5DDRPHY(Module, AutoCSR):
i_WRPNTR1 = wrpntr[1], i_WRPNTR1 = wrpntr[1],
i_WRPNTR2 = wrpntr[2], i_WRPNTR2 = wrpntr[2],
i_D = dq_i_delayed, i_D = dq_i_delayed,
o_Q0 = _dq_i_data[0], o_Q0 = dq_i_data[0],
o_Q1 = _dq_i_data[1], o_Q1 = dq_i_data[1],
o_Q2 = _dq_i_data[2], o_Q2 = dq_i_data[2],
o_Q3 = _dq_i_data[3], o_Q3 = dq_i_data[3],
) )
] ]
self.sync += dq_i_data[:4].eq(dq_i_data[4:]) dq_i_bitslip = BitSlip(4,
self.sync += dq_i_data[4:].eq(_dq_i_data) rst = self._dly_sel.storage[i] & self._rdly_dq_bitslip_rst.re,
slp = self._dly_sel.storage[i] & self._rdly_dq_bitslip.re,
cycles = 1)
self.submodules += dq_i_bitslip
dq_i_bitslip_o_d = Signal(4)
self.comb += dq_i_bitslip.i.eq(dq_i_data)
self.sync += dq_i_bitslip_o_d.eq(dq_i_bitslip.o)
self.comb += [ self.comb += [
dfi.phases[0].rddata[0*databits+j].eq(dq_i_data[0]), dfi.phases[0].rddata[0*databits+j].eq(dq_i_bitslip_o_d[0]),
dfi.phases[0].rddata[1*databits+j].eq(dq_i_data[1]), dfi.phases[0].rddata[1*databits+j].eq(dq_i_bitslip_o_d[1]),
dfi.phases[0].rddata[2*databits+j].eq(dq_i_data[2]), dfi.phases[0].rddata[2*databits+j].eq(dq_i_bitslip_o_d[2]),
dfi.phases[0].rddata[3*databits+j].eq(dq_i_data[3]), dfi.phases[0].rddata[3*databits+j].eq(dq_i_bitslip_o_d[3]),
dfi.phases[1].rddata[0*databits+j].eq(dq_i_data[4]), dfi.phases[1].rddata[0*databits+j].eq(dq_i_bitslip.o[0]),
dfi.phases[1].rddata[1*databits+j].eq(dq_i_data[5]), dfi.phases[1].rddata[1*databits+j].eq(dq_i_bitslip.o[1]),
dfi.phases[1].rddata[2*databits+j].eq(dq_i_data[6]), dfi.phases[1].rddata[2*databits+j].eq(dq_i_bitslip.o[2]),
dfi.phases[1].rddata[3*databits+j].eq(dq_i_data[7]), dfi.phases[1].rddata[3*databits+j].eq(dq_i_bitslip.o[3]),
] ]
self.specials += [ self.specials += [
Instance("TSHX2DQA", Instance("TSHX2DQA",
@ -429,8 +419,8 @@ class ECP5DDRPHY(Module, AutoCSR):
i_ECLK = ClockSignal("sys2x"), i_ECLK = ClockSignal("sys2x"),
i_SCLK = ClockSignal(), i_SCLK = ClockSignal(),
i_DQSW270 = dqsw270, i_DQSW270 = dqsw270,
i_T0 = ~(dqs_pattern.preamble | dq_oe | dqs_pattern.postamble), i_T0 = ~dq_oe,
i_T1 = ~(dqs_pattern.preamble | dq_oe | dqs_pattern.postamble), i_T1 = ~dq_oe,
o_Q = dq_oe_n, o_Q = dq_oe_n,
), ),
Tristate(pads.dq[j], dq_o, ~dq_oe_n, dq_i) Tristate(pads.dq[j], dq_o, ~dq_oe_n, dq_i)
@ -446,10 +436,13 @@ class ECP5DDRPHY(Module, AutoCSR):
# #
# The read data valid is asserted for 1 sys_clk cycle when the data is available on the DFI # The read data valid is asserted for 1 sys_clk cycle when the data is available on the DFI
# interface, the latency is the sum of the ODDRX2DQA, CAS, IDDRX2DQA latencies. # interface, the latency is the sum of the ODDRX2DQA, CAS, IDDRX2DQA latencies.
rddata_en = Signal(self.settings.read_latency)
rddata_en_last = Signal.like(rddata_en) rddata_en_last = Signal.like(rddata_en)
self.comb += rddata_en.eq(Cat(dfi.phases[self.settings.rdphase].rddata_en, rddata_en_last)) self.comb += rddata_en.eq(Cat(dfi.phases[self.settings.rdphase].rddata_en, rddata_en_last))
self.sync += rddata_en_last.eq(rddata_en) self.sync += rddata_en_last.eq(rddata_en)
self.sync += [phase.rddata_valid.eq(rddata_en[-1]) for phase in dfi.phases] self.sync += [phase.rddata_valid.eq(rddata_en[-1]) for phase in dfi.phases]
self.comb += dqs_re.eq(rddata_en[cl_sys_latency + 1] | rddata_en[cl_sys_latency + 2])
# Write Control Path ----------------------------------------------------------------------- # Write Control Path -----------------------------------------------------------------------
# Creates a shift register of write commands coming from the DFI interface. This shift register # Creates a shift register of write commands coming from the DFI interface. This shift register
@ -457,12 +450,11 @@ class ECP5DDRPHY(Module, AutoCSR):
# interface: The PHY is operating in halfrate mode (so provide 4 datas every sys_clk cycles: # interface: The PHY is operating in halfrate mode (so provide 4 datas every sys_clk cycles:
# 2x for DDR, 2x for halfrate) but DDR3 requires a burst of 8 datas (BL8) for best efficiency. # 2x for DDR, 2x for halfrate) but DDR3 requires a burst of 8 datas (BL8) for best efficiency.
# Writes are then performed in 2 sys_clk cycles and data needs to be selected for each cycle. # Writes are then performed in 2 sys_clk cycles and data needs to be selected for each cycle.
# FIXME: understand +2 wrdata_en = Signal(cwl_sys_latency + 4)
wrdata_en = Signal(cwl_sys_latency + 5)
wrdata_en_last = Signal.like(wrdata_en) wrdata_en_last = Signal.like(wrdata_en)
self.comb += wrdata_en.eq(Cat(dfi.phases[self.settings.wrphase].wrdata_en, wrdata_en_last)) self.comb += wrdata_en.eq(Cat(dfi.phases[self.settings.wrphase].wrdata_en, wrdata_en_last))
self.sync += wrdata_en_last.eq(wrdata_en) self.sync += wrdata_en_last.eq(wrdata_en)
self.comb += dq_oe.eq(wrdata_en[cwl_sys_latency + 2] | wrdata_en[cwl_sys_latency + 3]) self.comb += dq_oe.eq(wrdata_en[cwl_sys_latency + 1] | wrdata_en[cwl_sys_latency + 2])
self.comb += bl8_chunk.eq(wrdata_en[cwl_sys_latency + 1]) self.comb += bl8_chunk.eq(wrdata_en[cwl_sys_latency + 1])
self.comb += dqs_oe.eq(dq_oe) self.comb += dqs_oe.eq(dq_oe)
@ -470,5 +462,5 @@ class ECP5DDRPHY(Module, AutoCSR):
# Generates DQS Preamble 1 cycle before the first write and Postamble 1 cycle after the last # Generates DQS Preamble 1 cycle before the first write and Postamble 1 cycle after the last
# write. During writes, DQS tristate is configured as output for at least 4 sys_clk cycles: # write. During writes, DQS tristate is configured as output for at least 4 sys_clk cycles:
# 1 for Preamble, 2 for the Write and 1 for the Postamble. # 1 for Preamble, 2 for the Write and 1 for the Postamble.
self.comb += dqs_pattern.preamble.eq( wrdata_en[cwl_sys_latency + 1] & ~wrdata_en[cwl_sys_latency + 2]) self.comb += dqs_preamble.eq( wrdata_en[cwl_sys_latency + 0] & ~wrdata_en[cwl_sys_latency + 1])
self.comb += dqs_pattern.postamble.eq(wrdata_en[cwl_sys_latency + 4] & ~wrdata_en[cwl_sys_latency + 3]) self.comb += dqs_postamble.eq(wrdata_en[cwl_sys_latency + 3] & ~wrdata_en[cwl_sys_latency + 2])