diff options
Diffstat (limited to 'ice40/pack.cc')
| -rw-r--r-- | ice40/pack.cc | 125 |
1 files changed, 85 insertions, 40 deletions
diff --git a/ice40/pack.cc b/ice40/pack.cc index e045c05c..0b76f3f3 100644 --- a/ice40/pack.cc +++ b/ice40/pack.cc @@ -2,7 +2,7 @@ * nextpnr -- Next Generation Place and Route * * Copyright (C) 2018 Clifford Wolf <clifford@clifford.at> - * Copyright (C) 2018 David Shah <dave@ds0.me> + * Copyright (C) 2018 David Shah <david@symbioticeda.com> * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above @@ -276,15 +276,36 @@ static void pack_io(Design *design) } } -static bool is_clock_port(const PortRef &port) +static void insert_global(Design *design, NetInfo *net, bool is_reset, + bool is_cen) { - if (port.cell == nullptr) - return false; - if (is_ff(port.cell)) - return port.port == "C"; - if (is_ram(port.cell)) - return port.port == "RCLK" || port.port == "WCLK"; - return false; + CellInfo *gb = create_ice_cell(design, "SB_GB"); + gb->ports["USER_SIGNAL_TO_GLOBAL_BUFFER"].net = net; + PortRef pr; + pr.cell = gb; + pr.port = "USER_SIGNAL_TO_GLOBAL_BUFFER"; + net->users.push_back(pr); + + pr.cell = gb; + pr.port = "GLOBAL_BUFFER_OUTPUT"; + NetInfo *glbnet = new NetInfo(); + glbnet->name = net->name.str() + std::string("_glb_") + + (is_reset ? "sr" : (is_cen ? "ce" : "clk")); + glbnet->driver = pr; + design->nets[glbnet->name] = glbnet; + gb->ports["GLOBAL_BUFFER_OUTPUT"].net = glbnet; + std::vector<PortRef> keep_users; + for (auto user : net->users) { + if (is_clock_port(user) || (is_reset && is_reset_port(user)) || + (is_cen && is_enable_port(user))) { + user.cell->ports[user.port].net = glbnet; + glbnet->users.push_back(user); + } else { + keep_users.push_back(user); + } + } + net->users = keep_users; + design->cells[gb->name] = gb; } // Simple global promoter (clock only) @@ -292,48 +313,72 @@ static void promote_globals(Design *design) { log_info("Promoting globals..\n"); - std::unordered_map<IdString, int> clock_count; + std::unordered_map<IdString, int> clock_count, reset_count, cen_count; for (auto net : design->nets) { NetInfo *ni = net.second; if (ni->driver.cell != nullptr && !is_global_net(ni)) { clock_count[net.first] = 0; + reset_count[net.first] = 0; + cen_count[net.first] = 0; + for (auto user : ni->users) { if (is_clock_port(user)) clock_count[net.first]++; + if (is_reset_port(user)) + reset_count[net.first]++; + if (is_enable_port(user)) + cen_count[net.first]++; } } } - auto global_clock = std::max_element(clock_count.begin(), clock_count.end(), - [](const std::pair<IdString, int> &a, - const std::pair<IdString, int> &b) { - return a.second < b.second; - }); - if (global_clock->second > 0) { - NetInfo *clknet = design->nets[global_clock->first]; - CellInfo *gb = create_ice_cell(design, "SB_GB"); - gb->ports["USER_SIGNAL_TO_GLOBAL_BUFFER"].net = clknet; - PortRef pr; - pr.cell = gb; - pr.port = "USER_SIGNAL_TO_GLOBAL_BUFFER"; - clknet->users.push_back(pr); - - pr.cell = gb; - pr.port = "GLOBAL_BUFFER_OUTPUT"; - NetInfo *glbnet = new NetInfo(); - glbnet->name = clknet->name.str() + "_glb"; - glbnet->driver = pr; - design->nets[glbnet->name] = glbnet; - std::vector<PortRef> keep_users; - for (auto user : clknet->users) { - if (is_clock_port(user)) { - user.cell->ports[user.port].net = glbnet; - glbnet->users.push_back(user); - } else { - keep_users.push_back(user); - } + int prom_globals = 0, prom_resets = 0, prom_cens = 0; + int gbs_available = 8; + for (auto cell : design->cells) + if (is_gbuf(cell.second)) + --gbs_available; + while (prom_globals < gbs_available) { + auto global_clock = + std::max_element(clock_count.begin(), clock_count.end(), + [](const std::pair<IdString, int> &a, + const std::pair<IdString, int> &b) { + return a.second < b.second; + }); + + auto global_reset = + std::max_element(reset_count.begin(), reset_count.end(), + [](const std::pair<IdString, int> &a, + const std::pair<IdString, int> &b) { + return a.second < b.second; + }); + auto global_cen = + std::max_element(cen_count.begin(), cen_count.end(), + [](const std::pair<IdString, int> &a, + const std::pair<IdString, int> &b) { + return a.second < b.second; + }); + if (global_reset->second > global_clock->second && prom_resets < 4) { + NetInfo *rstnet = design->nets[global_reset->first]; + insert_global(design, rstnet, true, false); + ++prom_globals; + ++prom_resets; + clock_count.erase(rstnet->name); + reset_count.erase(rstnet->name); + + } else if (global_cen->second > global_clock->second && prom_cens < 4) { + NetInfo *cennet = design->nets[global_cen->first]; + insert_global(design, cennet, false, true); + ++prom_globals; + ++prom_cens; + cen_count.erase(cennet->name); + clock_count.erase(cennet->name); + } else if (global_clock->second != 0) { + NetInfo *clknet = design->nets[global_clock->first]; + insert_global(design, clknet, false, false); + ++prom_globals; + clock_count.erase(clknet->name); + } else { + break; } - clknet->users = keep_users; - design->cells[gb->name] = gb; } } |