techlibs/ecp5/ecp5_gsr.cc

   1 /*
   2  *  yosys -- Yosys Open SYnthesis Suite
   3  *
   4  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
   5  *  Copyright (C) 2019  David Shah <david@symbioticeda.com>
   6  *
   7  *  Permission to use, copy, modify, and/or distribute this software for any
   8  *  purpose with or without fee is hereby granted, provided that the above
   9  *  copyright notice and this permission notice appear in all copies.
  10  *
  11  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  17  *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  *
  19  */
  20
  21 #include "kernel/yosys.h"
  22 #include "kernel/sigtools.h"
  23
  24 USING_YOSYS_NAMESPACE
  25 PRIVATE_NAMESPACE_BEGIN
  26
  27 struct Ecp5GsrPass : public Pass {
  28         Ecp5GsrPass() : Pass("ecp5_gsr", "ECP5: handle GSR") { }
  29         void help() YS_OVERRIDE
  30         {
  31                 //   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
  32                 log("\n");
  33                 log("    ecp5_gsr [options] [selection]\n");
  34                 log("\n");
  35                 log("Trim active low async resets connected to GSR and resolve GSR parameter,\n");
  36                 log("if a GSR or SGSR primitive is used in the design.\n");
  37                 log("\n");
  38                 log("If any cell has the GSR parameter set to \"AUTO\", this will be resolved\n");
  39                 log("to \"ENABLED\" if a GSR primitive is present and the (* nogsr *) attribute\n");
  40                 log("is not set, otherwise it will be resolved to \"DISABLED\".\n");
  41                 log("\n");
  42         }
  43         void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
  44         {
  45                 log_header(design, "Executing ECP5_GSR pass (implement FF init values).\n");
  46
  47                 size_t argidx;
  48                 for (argidx = 1; argidx < args.size(); argidx++)
  49                 {
  50                         // if (args[argidx] == "-singleton") {
  51                         //      singleton_mode = true;
  52                         //      continue;
  53                         // }
  54                         break;
  55                 }
  56                 extra_args(args, argidx, design);
  57
  58                 for (auto module : design->selected_modules())
  59                 {
  60                         log("Handling GSR in %s.\n", log_id(module));
  61
  62                         SigMap sigmap(module);
  63
  64                         SigBit gsr;
  65                         bool found_gsr = false;
  66
  67                         for (auto cell : module->selected_cells())
  68                         {
  69                                 if (cell->type != ID(GSR) && cell->type != ID(SGSR))
  70                                         continue;
  71                                 if (found_gsr)
  72                                         log_error("Found more than one GSR or SGSR cell in module %s.\n", log_id(module));
  73                                 found_gsr = true;
  74                                 SigSpec sig_gsr = cell->getPort(ID(GSR));
  75                                 if (GetSize(sig_gsr) < 1)
  76                                         log_error("GSR cell %s has disconnected GSR input.\n", log_id(cell));
  77                                 gsr = sigmap(sig_gsr[0]);
  78                         }
  79
  80                         // Resolve GSR parameter
  81
  82                         for (auto cell : module->selected_cells())
  83                         {
  84                                 if (!cell->hasParam(ID(GSR)) || cell->getParam(ID(GSR)).decode_string() != "AUTO")
  85                                         continue;
  86
  87                                 bool gsren = found_gsr;
  88                                 if (cell->get_bool_attribute("\\nogsr"))
  89                                         gsren = false;
  90                                 cell->setParam(ID(GSR), gsren ? Const("ENABLED") : Const("DISABLED"));
  91
  92                         }
  93
  94                         if (!found_gsr)
  95                                 continue;
  96
  97                         // For finding active low FF inputs
  98                         pool<SigBit> inverted_gsr;
  99
 100                         log_debug("GSR net in module %s is %s.\n", log_id(module), log_signal(gsr));
 101                         for (auto cell : module->selected_cells())
 102                         {
 103                                 if (cell->type != ID($_NOT_))
 104                                         continue;
 105                                 SigSpec sig_a = cell->getPort(ID(A)), sig_y = cell->getPort(ID(Y));
 106                                 if (GetSize(sig_a) < 1 || GetSize(sig_y) < 1)
 107                                         continue;
 108                                 SigBit a = sigmap(sig_a[0]);
 109                                 if (a == gsr)
 110                                         inverted_gsr.insert(sigmap(sig_y[0]));
 111                         }
 112
 113                         for (auto cell : module->selected_cells())
 114                         {
 115                                 if (cell->type != ID(TRELLIS_FF))
 116                                         continue;
 117                                 if (!cell->hasParam(ID(GSR)) || cell->getParam(ID(GSR)).decode_string() != "ENABLED")
 118                                         continue;
 119                                 if (!cell->hasParam(ID(SRMODE)) || cell->getParam(ID(SRMODE)).decode_string() != "ASYNC")
 120                                         continue;
 121                                 SigSpec sig_lsr = cell->getPort(ID(LSR));
 122                                 if (GetSize(sig_lsr) < 1)
 123                                         continue;
 124                                 SigBit lsr = sigmap(sig_lsr[0]);
 125                                 if (!inverted_gsr.count(lsr))
 126                                         continue;
 127                                 cell->setParam(ID(SRMODE), Const("LSR_OVER_CE"));
 128                                 cell->unsetPort(ID(LSR));
 129                         }
 130
 131                 }
 132         }
 133 } Ecp5GsrPass;
 134
 135 PRIVATE_NAMESPACE_END