diff options
Diffstat (limited to 'ice40')
| -rw-r--r-- | ice40/pack.cc | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/ice40/pack.cc b/ice40/pack.cc index 17d004b5..e27d42e5 100644 --- a/ice40/pack.cc +++ b/ice40/pack.cc @@ -1101,6 +1101,30 @@ static void pack_special(Context *ctx) } } + auto MHz = [&](delay_t a) { return 1000.0 / ctx->getDelayNS(a); }; + auto equals_epsilon = [](delay_t a, delay_t b) { return (std::abs(a - b) / std::max(double(b), 1.0)) < 1e-3; }; + + auto set_period = [&](CellInfo *ci, IdString port, delay_t period) { + if (!ci->ports.count(port)) + return; + NetInfo *to = ci->ports.at(port).net; + if (to == nullptr) + return; + if (to->clkconstr != nullptr) { + if (!equals_epsilon(to->clkconstr->period.delay, period)) + log_warning(" Overriding derived constraint of %.1f MHz on net %s with user-specified constraint of " + "%.1f MHz.\n", + MHz(to->clkconstr->period.delay), to->name.c_str(ctx), MHz(period)); + return; + } + to->clkconstr = std::unique_ptr<ClockConstraint>(new ClockConstraint()); + to->clkconstr->low.delay = period / 2; + to->clkconstr->high.delay = period / 2; + to->clkconstr->period.delay = period; + log_info(" Derived frequency constraint of %.1f MHz for net %s\n", MHz(to->clkconstr->period.delay), + to->name.c_str(ctx)); + }; + for (auto cell : sorted(ctx->cells)) { CellInfo *ci = cell.second; if (is_sb_lfosc(ctx, ci)) { @@ -1112,10 +1136,12 @@ static void pack_special(Context *ctx) replace_port(ci, ctx->id("CLKLFPU"), packed.get(), ctx->id("CLKLFPU")); if (bool_or_default(ci->attrs, ctx->id("ROUTE_THROUGH_FABRIC"))) { replace_port(ci, ctx->id("CLKLF"), packed.get(), ctx->id("CLKLF_FABRIC")); + set_period(packed.get(), ctx->id("CLKLF_FABRIC"), 100000000); // 10kHz } else { replace_port(ci, ctx->id("CLKLF"), packed.get(), ctx->id("CLKLF")); std::unique_ptr<CellInfo> gb = create_padin_gbuf(ctx, packed.get(), ctx->id("CLKLF"), "$gbuf_" + ci->name.str(ctx) + "_lfosc"); + set_period(gb.get(), id_GLOBAL_BUFFER_OUTPUT, 100000000); // 10kHz new_cells.push_back(std::move(gb)); } new_cells.push_back(std::move(packed)); @@ -1132,12 +1158,26 @@ static void pack_special(Context *ctx) auto port = ctx->id("TRIM" + std::to_string(i)); replace_port(ci, port, packed.get(), port); } + std::string div = packed->params[ctx->id("CLKHF_DIV")].as_string(); + int frequency; + if (div == "0b00") + frequency = 48; + else if (div == "0b01") + frequency = 24; + else if (div == "0b10") + frequency = 12; + else if (div == "0b11") + frequency = 6; + else + log_error("Invalid HFOSC divider value '%s' - expecting 0b00, 0b01, 0b10 or 0b11\n", div.c_str()); if (bool_or_default(ci->attrs, ctx->id("ROUTE_THROUGH_FABRIC"))) { replace_port(ci, ctx->id("CLKHF"), packed.get(), ctx->id("CLKHF_FABRIC")); + set_period(packed.get(), ctx->id("CLKHF_FABRIC"), 1000000 / frequency); } else { replace_port(ci, ctx->id("CLKHF"), packed.get(), ctx->id("CLKHF")); std::unique_ptr<CellInfo> gb = create_padin_gbuf(ctx, packed.get(), ctx->id("CLKHF"), "$gbuf_" + ci->name.str(ctx) + "_hfosc"); + set_period(gb.get(), id_GLOBAL_BUFFER_OUTPUT, 1000000 / frequency); new_cells.push_back(std::move(gb)); } new_cells.push_back(std::move(packed)); |