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core/multiplexer/steerel_sel: add support for dynamic rd/rdcmd/wr/wrcmd phases. 

This is useful for development and also simplifies code (without using more resources when constants are used).
This commit is contained in:
Florent Kermarrec 2020-09-14 18:40:58 +02:00
parent 020cff1970
commit f5184b41b5
1 changed files with 11 additions and 17 deletions
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28
litedram/core/multiplexer.py
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@ -317,23 +317,17 @@ class Multiplexer(Module, AutoCSR):
Cat(*all_wrdata_mask).eq(~interface.wdata_we)
]
def steerer_sel(steerer, r_w_n):
def steerer_sel(steerer, access):
assert access in ["read", "write"]
r = []
for i in range(settings.phy.nphases):
s = steerer.sel[i].eq(STEER_NOP)
if r_w_n == "read":
if i == settings.phy.rdphase:
s = steerer.sel[i].eq(STEER_REQ)
elif i == settings.phy.rdcmdphase:
s = steerer.sel[i].eq(STEER_CMD)
elif r_w_n == "write":
if i == settings.phy.wrphase:
s = steerer.sel[i].eq(STEER_REQ)
elif i == settings.phy.wrcmdphase:
s = steerer.sel[i].eq(STEER_CMD)
else:
raise ValueError
r.append(s)
r.append(steerer.sel[i].eq(STEER_NOP))
if access == "read":
r.append(If(i == settings.phy.rdphase, steerer.sel[i].eq(STEER_REQ)))
r.append(If(i == settings.phy.rdcmdphase, steerer.sel[i].eq(STEER_CMD)))
if access == "write":
r.append(If(i == settings.phy.wrphase, steerer.sel[i].eq(STEER_REQ)))
r.append(If(i == settings.phy.wrcmdphase, steerer.sel[i].eq(STEER_CMD)))
return r
# Control FSM ------------------------------------------------------------------------------
@ -348,7 +342,7 @@ class Multiplexer(Module, AutoCSR):
choose_cmd.cmd.ready.eq(~choose_cmd.activate() | ras_allowed),
choose_req.cmd.ready.eq(cas_allowed)
),
steerer_sel(steerer, "read"),
steerer_sel(steerer, access="read"),
If(write_available,
# TODO: switch only after several cycles of ~read_available?
If(~read_available | max_read_time,
@ -369,7 +363,7 @@ class Multiplexer(Module, AutoCSR):
choose_cmd.cmd.ready.eq(~choose_cmd.activate() | ras_allowed),
choose_req.cmd.ready.eq(cas_allowed),
),
steerer_sel(steerer, "write"),
steerer_sel(steerer, access="write"),
If(read_available,
If(~write_available | max_write_time,
NextState("WTR")