diff --git a/litedram/phy/lpddr5/sim.py b/litedram/phy/lpddr5/sim.py index 4faa572..626b0f5 100644 --- a/litedram/phy/lpddr5/sim.py +++ b/litedram/phy/lpddr5/sim.py @@ -273,6 +273,7 @@ class CommandsSim(Module, AutoCSR): REF = self.refresh_handler(), MRW = self.mrw_handler(), DATA = self.data_handler(), + CAS = self.cas_handler(), # WRITE/MASKED-WRITE # READ # CAS @@ -376,6 +377,34 @@ class CommandsSim(Module, AutoCSR): ] ) + def cas_handler(self): + ws_wr = Signal() + ws_rd = Signal() + ws_fs = Signal() + dc = Signal(4) + wrx = Signal() + wxsa = Signal() + wxsb = Signal() + return self.cmd_one_step("CAS", + cond = self.ca_p[:4] == 0b1100, + body = [ + # TODO: implement WCK sync + ws_wr.eq(self.ca_p[4]), + ws_rd.eq(self.ca_p[5]), + ws_fs.eq(self.ca_p[6]), + dc.eq(self.ca_n[:4]), + wrx.eq(self.ca_n[4]), + wxsa.eq(self.ca_n[5]), + wxsb.eq(self.ca_n[6]), + If(sum([ws_wr, ws_rd, ws_fs]) > 1, + self.log.error("More than one WCK Sync bit in CAS command") + ), + If(reduce(or_, [dc, wrx, wxsa, wxsb]), + self.log.warn("Unsupported CAS function requested") + ), + ] + ) + def data_handler(self): data_cmds = { "MASKED-WRITE": self.ca_p[:3] == 0b010, @@ -405,9 +434,6 @@ class CommandsSim(Module, AutoCSR): self.cmd_info.row.eq(row), self.cmd_info.col.eq(col), self.cmd_info.valid.eq(1), - If(~self.cmd_info.ready, - self.log.error("Simulator CMD-to-DATA overflow") - ), # data latency If(self.cmd_info.we, self.data_latency.eq(self.mode_regs.wl - 1), @@ -505,11 +531,14 @@ class DataSim(Module, AutoCSR): gtkw_dbg["cmd_buf"] = self.cmd_buf self.comb += [ cmd_info.connect(self.cmd_buf.sink, omit={"ready", "valid"}), - # ~ready will signalize that somehow our buffer is full, which is an internal error - cmd_info.ready.eq(cmd_info.valid & self.cmd_buf.sink.ready), + cmd_info.ready.eq(1), # to latch a command only once we use an edge here, which we can do as there is no way # for 2 valid commands cycle-by-cycle self.cmd_buf.sink.valid.eq(edge(self, cmd_info.valid)), + # if for some reason buffer hasn't been cleared, then we have an error + If(self.cmd_buf.sink.valid & ~self.cmd_buf.sink.ready, + self.log.error("Simulator internal error: CMD-to-DATA overflow") + ), ] cmd = self.cmd_buf.source @@ -544,7 +573,7 @@ class DataSim(Module, AutoCSR): wr_start = Signal() rd_start = Signal() wr_delay = 1 - rd_delay = 0 + rd_delay = 2 self.comb += [ wr_start.eq(cmd.valid & cmd.we & latency_ready), rd_start.eq(cmd.valid & ~cmd.we & latency_ready),