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 from lambdasoc.periph import Peripheral
  11
  12 # PhaseInjector ------------------------------------------------------------------------------------
  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(self._command_issue.r_stb & self._command.r_data[4]),
  32             self._phase.rddata_en.eq(self._command_issue.r_stb & self._command.r_data[5]),
  33             self._phase.wrdata.eq(self._wrdata.r_data),
  34             self._phase.wrdata_mask.eq(0)
  35         ]
  36
  37         with m.If(self._command_issue.r_stb):
  38             m.d.comb += [
  39                 self._phase.cs_n.eq(Repl(value=~self._command.r_data[0], count=len(self._phase.cs_n))),
  40                 self._phase.we_n.eq(~self._command.r_data[1]),
  41                 self._phase.cas_n.eq(~self._command.r_data[2]),
  42                 self._phase.ras_n.eq(~self._command.r_data[3]),
  43             ]
  44         with m.Else():
  45             m.d.comb += [
  46                 self._phase.cs_n.eq(Repl(value=1, count=len(self._phase.cs_n))),
  47                 self._phase.we_n.eq(1),
  48                 self._phase.cas_n.eq(1),
  49                 self._phase.ras_n.eq(1),
  50             ]
  51
  52         with m.If(self._phase.rddata_valid):
  53             m.d.sync += self._rddata.w_data.eq(self._phase.rddata)
  54
  55         return m
  56
  57 # DFIInjector --------------------------------------------------------------------------------------
  58
  59 class DFIInjector(Elaboratable):
  60     def __init__(self, csr_bank, addressbits, bankbits, nranks, databits, nphases=1):
  61         self._nranks = nranks
  62
  63         self._inti  = dfi.Interface(addressbits, bankbits, nranks, databits, nphases)
  64         self.slave  = dfi.Interface(addressbits, bankbits, nranks, databits, nphases)
  65         self.master = dfi.Interface(addressbits, bankbits, nranks, databits, nphases)
  66
  67         self._control = csr_bank.csr(4, "rw")  # sel, cke, odt, reset_n
  68
  69         self._phases = []
  70         for n, phase in enumerate(self._inti.phases):
  71             self._phases += [PhaseInjector(CSRPrefixProxy(csr_bank, "p{}".format(n)), phase)]
  72
  73     def elaborate(self, platform):
  74         m = Module()
  75
  76         m.submodules += self._phases
  77
  78         with m.If(self._control.r_data[0]):
  79             m.d.comb += self.slave.connect(self.master)
  80         with m.Else():
  81             m.d.comb += self._inti.connect(self.master)
  82
  83         for i in range(self._nranks):
  84             m.d.comb += [phase.cke[i].eq(self._control.r_data[1]) for phase in self._inti.phases]
  85             m.d.comb += [phase.odt[i].eq(self._control.r_data[2]) for phase in self._inti.phases if hasattr(phase, "odt")]
  86         m.d.comb += [phase.reset_n.eq(self._control.r_data[3]) for phase in self._inti.phases if hasattr(phase, "reset_n")]
  87
  88         return m