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Merge pull request #142 from antmicro/updated-trefi-verifier 

Update tREFI verifier
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enjoy-digital 2020-02-15 16:32:41 +01:00 committed by GitHub
parent 0ba31d6d8e 13d0350436
commit 95b827d435
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 31 additions and 4 deletions
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35
litedram/phy/model.py
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@ -223,6 +223,7 @@ class DFITimingsChecker(Module):
self.timings = new_timings
def __init__(self, dfi, nbanks, nphases, timings, refresh_mode, memtype, verbose=False):
ref_limit = {"1x": 9, "2x": 17, "4x": 36}
self.prepare_timings(timings, refresh_mode, memtype)
self.add_cmds()
self.add_rules()
@ -297,13 +298,39 @@ class DFITimingsChecker(Module):
# tREFI
ref_ps = Signal().like(cnt)
ref_done = Signal()
self.sync += If(ref_issued != 0, ref_ps.eq(ps), ref_done.eq(1),
If(~ref_done, Display("[%016dps] Late refresh", ps)))
ref_ps_mod = Signal().like(cnt)
ref_ps_diff = Signal(min=-2**63, max=2**63)
curr_diff = Signal().like(ref_ps_diff)
self.sync += If((ps > (ref_ps + self.timings["tREFI"])) & ref_done & (ref_issued == 0),
self.comb += curr_diff.eq(ps - (ref_ps + self.timings["tREFI"]))
# Work in 64ms periods
self.sync += If(ref_ps_mod < int(64e9),
ref_ps_mod.eq(ref_ps_mod + nphases * self.timings["tCK"])).Else(ref_ps_mod.eq(0))
# Update timestamp and difference
self.sync += If(ref_issued != 0, ref_ps.eq(ps), ref_ps_diff.eq(ref_ps_diff - curr_diff))
self.sync += If((ref_ps_mod == 0) & (ref_ps_diff > 0),
Display("[%016dps] tREFI violation (64ms period): %0d", ps, ref_ps_diff))
# Report any refresh periods longer than tREFI
if verbose:
ref_done = Signal()
self.sync += If(ref_issued != 0, ref_done.eq(1),
If(~ref_done, Display("[%016dps] Late refresh", ps)))
self.sync += If((curr_diff > 0) & ref_done & (ref_issued == 0),
Display("[%016dps] tREFI violation", ps), ref_done.eq(0))
# There is a maximum delay between refreshes on >=DDR
if memtype != "SDR":
refresh_mode = "1x" if refresh_mode is None else refresh_mode
ref_done = Signal()
self.sync += If(ref_issued != 0, ref_done.eq(1))
self.sync += If((ref_issued == 0) & ref_done & (ref_ps > (ps + ref_limit[refresh_mode] * self.timings['tREFI'])),
Display("[%016dps] tREFI violation (too many postponed refreshes)", ps), ref_done.eq(0))
# SDRAM PHY Model ----------------------------------------------------------------------------------
class SDRAMPHYModel(Module):