gram/dfii.py

   1 # This file is Copyright (c) 2015 Sebastien Bourdeauducq <sb@m-labs.hk>
   2 # This file is Copyright (c) 2016-2019 Florent Kermarrec <florent@enjoy-digital.fr>
   3 # This file is Copyright (c) 2020 LambdaConcept <contact@lambdaconcept.com>
   4 # License: BSD
   5
   6 from nmigen import *
   7
   8 from gram.phy import dfi
   9 from gram.compat import CSRPrefixProxy
  10
  11 # PhaseInjector ------------------------------------------------------------------------------------
  12
  13
  14 class PhaseInjector(Elaboratable):
  15     def __init__(self, csr_bank, phase):
  16         self._command = csr_bank.csr(6, "rw")
  17         self._command_issue = csr_bank.csr(1, "rw")
  18         self._address = csr_bank.csr(len(phase.address), "rw")
  19         self._baddress = csr_bank.csr(len(phase.bank), "rw")
  20         self._wrdata = csr_bank.csr(len(phase.wrdata), "rw")
  21         self._rddata = csr_bank.csr(len(phase.rddata), "rw")
  22
  23         self._phase = phase
  24
  25     def elaborate(self, platform):
  26         m = Module()
  27
  28         m.d.comb += [
  29             self._phase.address.eq(self._address.r_data),
  30             self._phase.bank.eq(self._baddress.r_data),
  31             self._phase.wrdata_en.eq(
  32                 self._command_issue.r_stb & self._command.r_data[4]),
  33             self._phase.rddata_en.eq(
  34                 self._command_issue.r_stb & self._command.r_data[5]),
  35             self._phase.wrdata.eq(self._wrdata.r_data),
  36             self._phase.wrdata_mask.eq(0)
  37         ]
  38
  39         with m.If(self._command_issue.r_stb):
  40             m.d.comb += [
  41                 self._phase.cs_n.eq(Repl(value=~self._command.r_data[0], count=len(self._phase.cs_n))),
  42                 self._phase.we_n.eq(~self._command.r_data[1]),
  43                 self._phase.cas_n.eq(~self._command.r_data[2]),
  44                 self._phase.ras_n.eq(~self._command.r_data[3]),
  45             ]
  46         with m.Else():
  47             m.d.comb += [
  48                 self._phase.cs_n.eq(Repl(value=1, count=len(self._phase.cs_n))),
  49                 self._phase.we_n.eq(1),
  50                 self._phase.cas_n.eq(1),
  51                 self._phase.ras_n.eq(1),
  52             ]
  53
  54         with m.If(self._phase.rddata_valid):
  55             m.d.sync += self._rddata.r_data.eq(self._phase.rddata)
  56
  57         return m
  58
  59 # DFIInjector --------------------------------------------------------------------------------------
  60
  61
  62 class DFIInjector(Elaboratable):
  63     def __init__(self, csr_bank, addressbits, bankbits, nranks, databits, nphases=1):
  64         self._nranks = nranks
  65
  66         self._inti = dfi.Interface(
  67             addressbits, bankbits, nranks, databits, nphases)
  68         self.slave = dfi.Interface(
  69             addressbits, bankbits, nranks, databits, nphases)
  70         self.master = dfi.Interface(
  71             addressbits, bankbits, nranks, databits, nphases)
  72
  73         self._control = csr_bank.csr(4, "rw")  # sel, cke, odt, reset_n
  74
  75         self._phases = []
  76         for n, phase in enumerate(self._inti.phases):
  77             self._phases += [PhaseInjector(CSRPrefixProxy(csr_bank,
  78                                                           "p{}".format(n)), phase)]
  79
  80     def elaborate(self, platform):
  81         m = Module()
  82
  83         m.submodules += self._phases
  84
  85         with m.If(self._control.r_data[0]):
  86             m.d.comb += self.slave.connect(self.master)
  87         with m.Else():
  88             m.d.comb += self._inti.connect(self.master)
  89
  90         for i in range(self._nranks):
  91             m.d.comb += [phase.cke[i].eq(self._control.r_data[1])
  92                          for phase in self._inti.phases]
  93             m.d.comb += [phase.odt[i].eq(self._control.r_data[2])
  94                          for phase in self._inti.phases if hasattr(phase, "odt")]
  95         m.d.comb += [phase.reset_n.eq(self._control.r_data[3])
  96                      for phase in self._inti.phases if hasattr(phase, "reset_n")]
  97
  98         return m