src/soc/simple/core.py

   1 """simple core
   2
   3 not in any way intended for production use.  connects up FunctionUnits to
   4 Register Files in a brain-dead fashion that only permits one and only one
   5 Function Unit to be operational.
   6 """
   7 from nmigen import Elaboratable, Module, Signal
   8 from nmigen.cli import rtlil
   9
  10 from nmutil.picker import PriorityPicker
  11 from nmutil.util import treereduce
  12
  13 from soc.fu.compunits.compunits import AllFunctionUnits
  14 from soc.regfile.regfiles import RegFiles
  15 from soc.decoder.power_decoder import create_pdecode
  16 from soc.decoder.power_decoder2 import PowerDecode2
  17
  18
  19
  20 def ortreereduce(tree, attr="data_o"):
  21     return treereduce(tree, operator.or_, lambda x: getattr(x, attr))
  22
  23
  24 class NonProductionCore(Elaboratable):
  25     def __init__(self):
  26         self.fus = AllFunctionUnits()
  27         self.regs = RegFiles()
  28         self.pdecode = pdecode = create_pdecode()
  29         self.pdecode2 = PowerDecode2(pdecode)   # instruction decoder
  30         self.ivalid_i = self.pdecode2.e.valid   # instruction is valid
  31
  32     def elaborate(self, platform):
  33         m = Module()
  34         comb = m.d.comb
  35
  36         m.submodules.pdecode2 = dec2 = self.pdecode2
  37         m.submodules.fus = self.fus
  38         self.regs.elaborate_into(m, platform)
  39         regs = self.regs
  40         fus = self.fus.fus
  41
  42         # enable-signals for each FU, get one bit for each FU (by name)
  43         fu_enable = Signal(len(fus), reset_less=True)
  44         fu_bitdict = {}
  45         for i, funame in enumerate(fus.keys()):
  46             fu_bitdict[funame] = fu_enable[i]
  47
  48         # dictionary of lists of regfile read ports
  49         byregfiles_rd = {}
  50         byregfiles_rdspec = {}
  51         for (funame, fu) in fus.items():
  52             print ("read ports for %s" % funame)
  53             for idx in range(fu.n_src):
  54                 (regfile, regname, wid) = fu.get_in_spec(idx)
  55                 print ("    %s %s %s" % (regfile, regname, str(wid)))
  56                 rdflag, read, _ = dec2.regspecmap(regfile, regname)
  57                 if regfile not in byregfiles_rd:
  58                     byregfiles_rd[regfile] = {}
  59                     byregfiles_rdspec[regfile] = (regname, rdflag, read, wid)
  60                 # here we start to create "lanes"
  61                 if idx not in byregfiles_rd[regfile]:
  62                     byregfiles_rd[regfile][idx] = []
  63                 fuspec = (funame, fu)
  64                 byregfiles_rd[regfile][idx].append(fuspec)
  65
  66         # ok just print that out, for convenience
  67         for regfile, spec in byregfiles_rd.items():
  68             print ("regfile read ports:", regfile)
  69             for idx, fuspec in spec.items():
  70                 print ("  regfile read port %s lane: %d" % (regfile, idx))
  71                 (regname, rdflag, read, wid) = byregfiles_rdspec[regfile]
  72                 print ("  %s" % regname, wid, read, rdflag)
  73                 for (funame, fu) in fuspec:
  74                     print ("    ", funame, fu, fu.src_i[idx])
  75                     print ()
  76
  77         # okaay, now we need a PriorityPicker per regfile per regfile port
  78         # loootta pickers... peter piper picked a pack of pickled peppers...
  79         rdpickers = {}
  80         for regfile, spec in byregfiles_rd.items():
  81             rdpickers[regfile] = {}
  82             for rpidx, (idx, fuspec) in enumerate(spec.items()):
  83                 # get the regfile specs for this regfile port
  84                 (regname, rdflag, read, wid) = byregfiles_rdspec[regfile]
  85
  86                 # "munge" the regfile port index, due to full-port access
  87                 if regfile in ['xer', 'cr']:
  88                     if regname.startswith('full'):
  89                         rpidx = 0 # by convention, first port
  90                     else:
  91                         rpidx += 1 # start indexing port 0 from 1
  92
  93                 # select the required read port.  these are pre-defined sizes
  94                 print (regfile, regs.rf.keys())
  95                 rport = regs.rf[regfile.lower()].r_ports[rpidx]
  96
  97                 # create a priority picker to manage this port
  98                 rdpickers[regfile][idx] = rdpick = PriorityPicker(len(fuspec))
  99                 setattr(m.submodules, "rdpick_%s_%d" % (regfile, idx), rdpick)
 100
 101                 # connect the regspec "reg select" number to this port
 102                 with m.If(rdpick.en_o):
 103                     comb += rport.ren.eq(read)
 104
 105                 # connect up the FU req/go signals and the reg-read to the FU
 106                 for pi, (funame, fu) in enumerate(fuspec):
 107                     # connect request-read to picker input, and output to go-rd
 108                     fu_active = fu_bitdict[funame]
 109                     comb += rdpick.i[pi].eq(fu.rd_rel_o[idx] & fu_active)
 110                     comb += fu.go_rd_i[idx].eq(rdpick.o[pi])
 111                     # connect regfile port to input
 112                     comb += fu.src_i[idx].eq(rport.data_o)
 113
 114         return m
 115
 116     def __iter__(self):
 117         yield from self.fus.ports()
 118         yield from self.pdecode2.ports()
 119         # TODO: regs
 120
 121     def ports(self):
 122         return list(self)
 123
 124
 125 if __name__ == '__main__':
 126     dut = NonProductionCore()
 127     vl = rtlil.convert(dut, ports=dut.ports())
 128     with open("non_production_core.il", "w") as f:
 129         f.write(vl)