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ddr4: Enable Data Mask for DDR4 memory and invert its polarity.

This commit is contained in:
Jędrzej Boczar 2020-11-17 15:06:11 +01:00 committed by Florent Kermarrec
parent 1117068595
commit 6b9f1bd0d8
2 changed files with 7 additions and 2 deletions
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4
litedram/init.py
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@ -355,6 +355,8 @@ def get_ddr4_phy_init_sequence(phy_settings, timing_settings):
rtt_wr = "120ohm" rtt_wr = "120ohm"
ron = "34ohm" ron = "34ohm"
tdqs = 0 tdqs = 0
dm = 1
assert not (dm and tdqs)
# override electrical settings if specified # override electrical settings if specified
if hasattr(phy_settings, "rtt_nom"): if hasattr(phy_settings, "rtt_nom"):
@ -372,7 +374,7 @@ def get_ddr4_phy_init_sequence(phy_settings, timing_settings):
mr2 = format_mr2(cwl, z_to_rtt_wr[rtt_wr]) mr2 = format_mr2(cwl, z_to_rtt_wr[rtt_wr])
mr3 = format_mr3(timing_settings.fine_refresh_mode) mr3 = format_mr3(timing_settings.fine_refresh_mode)
mr4 = 0 mr4 = 0
mr5 = 0 mr5 = (dm << 10)
mr6 = format_mr6(4) # FIXME: tCCD mr6 = format_mr6(4) # FIXME: tCCD
rdimm_init = [] rdimm_init = []

5
litedram/phy/usddrphy.py
View File

@ -311,9 +311,12 @@ class USDDRPHY(Module, AutoCSR):
# DM --------------------------------------------------------------------------------------- # DM ---------------------------------------------------------------------------------------
for i in range(databits//8): for i in range(databits//8):
if hasattr(pads, "dm"): if hasattr(pads, "dm"):
dm_i = Cat(*[dfi.phases[n//2].wrdata_mask[n%2*databits//8+i] for n in range(8)])
if memtype == "DDR4": # Inverted polarity for DDR4
dm_i = ~dm_i
dm_o_nodelay = Signal() dm_o_nodelay = Signal()
dm_o_bitslip = BitSlip(8, dm_o_bitslip = BitSlip(8,
i = Cat(*[dfi.phases[n//2].wrdata_mask[n%2*databits//8+i] for n in range(8)]), i = dm_i,
rst = (self._dly_sel.storage[i] & self._wdly_dq_bitslip_rst.re) | self._rst.storage, rst = (self._dly_sel.storage[i] & self._wdly_dq_bitslip_rst.re) | self._rst.storage,
slp = self._dly_sel.storage[i] & self._wdly_dq_bitslip.re, slp = self._dly_sel.storage[i] & self._wdly_dq_bitslip.re,
cycles = 1) cycles = 1)