gram/phy/dfi.py

   1 # This file is Copyright (c) 2015 Sebastien Bourdeauducq <sb@m-labs.hk>
   2 # This file is Copyright (c) 2020 LambdaConcept <contact@lambdaconcept.com>
   3
   4 from nmigen import *
   5 from nmigen.hdl.rec import *
   6
   7 __ALL__ = ["Interface"]
   8
   9
  10 def phase_description(addressbits, bankbits, nranks, databits):
  11     return [
  12         # cmd description
  13         ("address", addressbits, DIR_FANOUT),
  14         ("bank",       bankbits, DIR_FANOUT),
  15         ("cas_n",             1, DIR_FANOUT),
  16         ("cs_n",         nranks, DIR_FANOUT),
  17         ("ras_n",             1, DIR_FANOUT),
  18         ("we_n",              1, DIR_FANOUT),
  19         ("cke",          nranks, DIR_FANOUT),
  20         ("odt",          nranks, DIR_FANOUT),
  21         ("reset_n",           1, DIR_FANOUT),
  22         ("act_n",             1, DIR_FANOUT),
  23         # wrdata description
  24         ("wrdata",         databits, DIR_FANOUT),
  25         ("wrdata_en",             1, DIR_FANOUT),
  26         ("wrdata_mask", databits//8, DIR_FANOUT),
  27         # rddata description
  28         ("rddata_en",           1, DIR_FANOUT),
  29         ("rddata",       databits, DIR_FANIN),
  30         ("rddata_valid",        1, DIR_FANIN),
  31     ]
  32
  33
  34 class Interface:
  35     def __init__(self, addressbits, bankbits, nranks, databits, nphases=1):
  36         self.phases = []
  37         for p in range(nphases):
  38             p = Record(phase_description(
  39                 addressbits, bankbits, nranks, databits))
  40             self.phases += [p]
  41             p.cas_n.reset = 1
  42             p.cs_n.reset = (2**nranks-1)
  43             p.ras_n.reset = 1
  44             p.we_n.reset = 1
  45             p.act_n.reset = 1
  46
  47     def connect(self, target):
  48         if not isinstance(target, Interface):
  49             raise TypeError("Target must be an instance of Interface, not {!r}"
  50                             .format(target))
  51
  52         ret = []
  53         for i in range(min(len(self.phases), len(target.phases))):
  54             ret += [self.phases[i].connect(target.phases[i])]
  55
  56         return ret