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core: make tRRD definition optional and some cosmetic changes

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This commit is contained in:
Florent Kermarrec 2018-08-08 12:24:07 +02:00
parent 5d74eb249f
commit e02a251cde
2 changed files with 16 additions and 15 deletions
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29
litedram/core/multiplexer.py
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@ -114,7 +114,7 @@ class Multiplexer(Module, AutoCSR):
# Forward Declares
activate_allowed = Signal(reset=1)
# Command choosing
requests = [bm.cmd for bm in bank_machines]
self.submodules.choose_cmd = choose_cmd = _CommandChooser(requests)
@ -136,19 +136,20 @@ class Multiplexer(Module, AutoCSR):
self.submodules += steerer
# tRRD Command Timing
tRRD = settings.timing.tRRD
trrd = settings.timing.tRRD
trrd_allowed = Signal(reset=1)
activate_count = Signal(max=tRRD)
is_act_cmd = Signal()
self.comb += is_act_cmd.eq(choose_cmd.cmd.ras & ~choose_cmd.cmd.cas & ~choose_cmd.cmd.we)
self.sync += \
If(choose_cmd.cmd.ready & choose_cmd.cmd.valid & is_act_cmd,
activate_count.eq(tRRD-1)
).Elif(~activate_allowed,
activate_count.eq(activate_count-1)
)
self.comb += trrd_allowed.eq(activate_count == 0)
if trrd is not None:
trrd_count = Signal(max=trrd+1)
is_act_cmd = Signal()
self.comb += is_act_cmd.eq(choose_cmd.cmd.ras & ~choose_cmd.cmd.cas & ~choose_cmd.cmd.we)
self.sync += \
If(choose_cmd.cmd.ready & choose_cmd.cmd.valid & is_act_cmd,
trrd_count.eq(trrd-1)
).Elif(~activate_allowed,
trrd_count.eq(trrd_count-1)
)
self.comb += trrd_allowed.eq(trrd_count == 0)
# tFAW Command Timing
tfaw = settings.timing.tFAW
tfaw_allowed = Signal(reset=1)
@ -164,7 +165,7 @@ class Multiplexer(Module, AutoCSR):
self.comb += activate_allowed.eq(trrd_allowed & tfaw_allowed)
self.comb += [bm.activate_allowed.eq(activate_allowed) for bm in bank_machines]
# CAS to CAS
cas = choose_req.cmd.valid & choose_req.cmd.ready & (choose_req.cmd.is_read | choose_req.cmd.is_write)
cas_allowed = Signal(reset=1)

2
litedram/modules.py
View file

@ -34,7 +34,7 @@ class SDRAMModule:
tWTR=self.ck_ns_to_cycles(*self.get("tWTR")),
tFAW=None if self.get("tFAW") is None else self.ck_ns_to_cycles(*self.get("tFAW")),
tCCD=None if self.get("tCCD") is None else self.ck_ns_to_cycles(*self.get("tCCD")),
tRRD=self.ns_to_cycles_trrd(self.get("tRRD")),
tRRD=None if self.get("tRRD") is None else self.ns_to_cycles_trrd(self.get("tRRD")),
)
def get(self, name):