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

core/multiplexer: fix command steering for nphases=1 (SDRAM), thanks jfng

This commit is contained in:
Florent Kermarrec 2019-01-17 09:04:01 +01:00
parent 224a423082
commit b4c552a77f
1 changed files with 18 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
litedram/core/multiplexer.py
View File

@ -176,12 +176,10 @@ class Multiplexer(Module, AutoCSR):
self.submodules.choose_cmd = choose_cmd = _CommandChooser(requests)
self.submodules.choose_req = choose_req = _CommandChooser(requests)
if settings.phy.nphases == 1:
self.comb += [
choose_cmd.want_cmds.eq(1),
choose_cmd.want_activates.eq(ras_allowed),
choose_req.want_cmds.eq(1),
choose_req.want_activates.eq(ras_allowed),
]
# When only 1 phase, use choose_req for all requests
choose_cmd = choose_req
self.comb += choose_req.want_cmds.eq(1)
self.comb += choose_req.want_activates.eq(ras_allowed)
# Command steering
nop = Record(cmd_request_layout(settings.geom.addressbits,
@ -286,9 +284,13 @@ class Multiplexer(Module, AutoCSR):
fsm.act("READ",
read_time_en.eq(1),
choose_req.want_reads.eq(1),
If(settings.phy.nphases == 1,
choose_req.cmd.ready.eq(cas_allowed & (~choose_req.activate() | ras_allowed))
).Else(
choose_cmd.want_activates.eq(ras_allowed),
choose_cmd.cmd.ready.eq(~choose_cmd.activate() | ras_allowed),
choose_req.cmd.ready.eq(cas_allowed),
choose_req.cmd.ready.eq(cas_allowed)
),
steerer_sel(steerer, "read"),
If(write_available,
# TODO: switch only after several cycles of ~read_available?
@ -303,9 +305,13 @@ class Multiplexer(Module, AutoCSR):
fsm.act("WRITE",
write_time_en.eq(1),
choose_req.want_writes.eq(1),
If(settings.phy.nphases == 1,
choose_req.cmd.ready.eq(cas_allowed & (~choose_req.activate() | ras_allowed))
).Else(
choose_cmd.want_activates.eq(ras_allowed),
choose_cmd.cmd.ready.eq(~choose_cmd.activate() | ras_allowed),
choose_req.cmd.ready.eq(cas_allowed),
),
steerer_sel(steerer, "write"),
If(read_available,
If(~write_available | max_write_time,