techlibs/ice40/ice40_ffinit.cc

   1 /*
   2  *  yosys -- Yosys Open SYnthesis Suite
   3  *
   4  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
   5  *
   6  *  Permission to use, copy, modify, and/or distribute this software for any
   7  *  purpose with or without fee is hereby granted, provided that the above
   8  *  copyright notice and this permission notice appear in all copies.
   9  *
  10  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  */
  19
  20 #include "kernel/yosys.h"
  21 #include "kernel/sigtools.h"
  22
  23 USING_YOSYS_NAMESPACE
  24 PRIVATE_NAMESPACE_BEGIN
  25
  26 struct Ice40FfinitPass : public Pass {
  27         Ice40FfinitPass() : Pass("ice40_ffinit", "iCE40: handle FF init values") { }
  28         virtual void help()
  29         {
  30                 //   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
  31                 log("\n");
  32                 log("    ice40_ffinit [options] [selection]\n");
  33                 log("\n");
  34                 log("Remove zero init values for FF output signals. Add inverters to implement\n");
  35                 log("nonzero init values.\n");
  36                 log("\n");
  37         }
  38         virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
  39         {
  40                 log_header("Executing ICE40_FFINIT pass (implement FF init values).\n");
  41
  42                 size_t argidx;
  43                 for (argidx = 1; argidx < args.size(); argidx++)
  44                 {
  45                         // if (args[argidx] == "-singleton") {
  46                         //      singleton_mode = true;
  47                         //      continue;
  48                         // }
  49                         break;
  50                 }
  51                 extra_args(args, argidx, design);
  52
  53                 for (auto module : design->selected_modules())
  54                 {
  55                         log("Handling FF init values in %s.\n", log_id(module));
  56
  57                         SigMap sigmap(module);
  58                         pool<Wire*> init_wires;
  59                         dict<SigBit, State> initbits;
  60                         pool<SigBit> handled_initbits;
  61
  62                         for (auto wire : module->selected_wires())
  63                         {
  64                                 if (wire->attributes.count("\\init") == 0)
  65                                         continue;
  66
  67                                 SigSpec wirebits = sigmap(wire);
  68                                 Const initval = wire->attributes.at("\\init");
  69                                 init_wires.insert(wire);
  70
  71                                 for (int i = 0; i < GetSize(wirebits) && i < GetSize(initval); i++)
  72                                 {
  73                                         SigBit bit = wirebits[i];
  74                                         State val = initval[i];
  75
  76                                         if (val != State::S0 && val != State::S1)
  77                                                 continue;
  78
  79                                         if (initbits.count(bit)) {
  80                                                 if (initbits.at(bit) != val)
  81                                                         log_error("Conflicting init values for signal %s.\n", log_signal(bit));
  82                                                 continue;
  83                                         }
  84
  85                                         initbits[bit] = val;
  86                                 }
  87                         }
  88
  89                         for (auto cell : module->selected_cells())
  90                         {
  91                                 if (!cell->type.in("\\SB_DFF", "\\SB_DFFE", "\\SB_DFFN", "\\SB_DFFNE"))
  92                                         continue;
  93
  94                                 SigBit sig_d = sigmap(cell->getPort("\\D"));
  95                                 SigBit sig_q = sigmap(cell->getPort("\\Q"));
  96
  97                                 if (!initbits.count(sig_q))
  98                                         continue;
  99
 100                                 State val = initbits.at(sig_q);
 101                                 handled_initbits.insert(sig_q);
 102
 103                                 log("FF init value for cell %s (%s): %s = %c\n", log_id(cell), log_id(cell->type),
 104                                                 log_signal(sig_q), val != State::S0 ? '1' : '0');
 105
 106                                 if (val == State::S0)
 107                                         continue;
 108
 109                                 Wire *new_sig_d = module->addWire(NEW_ID);
 110                                 Wire *new_sig_q = module->addWire(NEW_ID);
 111
 112                                 module->addNotGate(NEW_ID, sig_d, new_sig_d);
 113                                 module->addNotGate(NEW_ID, new_sig_q, sig_q);
 114
 115                                 cell->setPort("\\D", new_sig_d);
 116                                 cell->setPort("\\Q", new_sig_q);
 117                         }
 118
 119                         for (auto wire : init_wires)
 120                         {
 121                                 if (wire->attributes.count("\\init") == 0)
 122                                         continue;
 123
 124                                 SigSpec wirebits = sigmap(wire);
 125                                 Const &initval = wire->attributes.at("\\init");
 126                                 bool remove_attribute = true;
 127
 128                                 for (int i = 0; i < GetSize(wirebits) && i < GetSize(initval); i++) {
 129                                         if (handled_initbits.count(wirebits[i]))
 130                                                 wirebits[i] = State::Sx;
 131                                         else
 132                                                 remove_attribute = false;
 133                                 }
 134
 135                                 if (remove_attribute)
 136                                         wire->attributes.erase("\\init");
 137                         }
 138                 }
 139         }
 140 } Ice40FfinitPass;
 141
 142 PRIVATE_NAMESPACE_END