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gowin: improve clock wire routing

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The dedicated router for clock wires now understands not only the IO
pins but also the rPLL outputs as clock sources.

This simple router sets an optimal route, so it is now the default
router. It can be disabled with the --disable-globals command line flag
if desired, but this is not recommended due to possible clock skew.

Still for GW1N-4C there is no good router for clock wires as there
external quartz resonator is connected via PLL.

Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
This commit is contained in:
YRabbit 2022-12-30 11:55:39 +10:00
parent 8424dc79d2
commit b8ab3116b2
5 changed files with 69 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
gowin/arch.cc
View File

@ -2016,6 +2016,16 @@ static bool is_PLL_T_FB_iob(const Context *ctx, const CellInfo *cell)
return is_spec_iob(ctx, cell, ctx->id("RPLL_T_FB"));
}
bool Arch::is_GCLKT_iob(const CellInfo *cell)
{
for (int i = 0; i < 6; ++i) {
if (is_spec_iob(getCtx(), cell, idf("GCLKT_%d", i))) {
return true;
}
}
return false;
}
// If the PLL input can be connected using a direct wire, then do so,
// bypassing conventional routing.
void Arch::fix_pll_nets(Context *ctx)

1
gowin/arch.h
View File

@ -480,6 +480,7 @@ struct Arch : BaseArch<ArchRanges>
void auto_longwires();
void add_plla_ports(BelsPOD const *bel, IdString belname, int row, int col);
void fix_pll_nets(Context *ctx);
bool is_GCLKT_iob(const CellInfo *cell);
GowinGlobalRouter globals_router;
void mark_gowin_globals(Context *ctx);

67
gowin/globals.cc
View File

@ -38,22 +38,28 @@ bool GowinGlobalRouter::is_clock_port(PortRef const &user)
return false;
}
std::pair<WireId, BelId> GowinGlobalRouter::clock_io(Context *ctx, PortRef const &driver)
std::pair<WireId, BelId> GowinGlobalRouter::clock_src(Context *ctx, PortRef const &driver)
{
// XXX normally all alternative functions of the pins should be passed
// in the chip database, but at the moment we find them from aliases/pips
// XXX check diff inputs too
if (driver.cell == nullptr || driver.cell->type != id_IOB || !driver.cell->attrs.count(id_BEL)) {
if (driver.cell == nullptr) {
return std::make_pair(WireId(), BelId());
}
// clock IOs have pips output->SPINExx
BelInfo &bel = ctx->bel_info(ctx->id(driver.cell->attrs[id_BEL].as_string()));
WireId wire = bel.pins[id_O].wire;
for (auto const pip : ctx->getPipsDownhill(wire)) {
if (ctx->wire_info(ctx->getPipDstWire(pip)).type.str(ctx).rfind("SPINE", 0) == 0) {
BelInfo &bel = ctx->bel_info(driver.cell->bel);
WireId wire;
if (driver.cell->type == id_IOB) {
if (ctx->is_GCLKT_iob(driver.cell)) {
wire = bel.pins[id_O].wire;
return std::make_pair(wire, bel.name);
}
return std::make_pair(WireId(), BelId());
}
if (driver.cell->type == id_RPLLA) {
if (driver.port == id_CLKOUT || driver.port == id_CLKOUTP || driver.port == id_CLKOUTD ||
driver.port == id_CLKOUTD3) {
wire = bel.pins[driver.port].wire;
return std::make_pair(wire, bel.name);
}
return std::make_pair(WireId(), BelId());
}
return std::make_pair(WireId(), BelId());
}
@ -64,12 +70,12 @@ void GowinGlobalRouter::gather_clock_nets(Context *ctx, std::vector<globalnet_t>
for (auto const &net : ctx->nets) {
NetInfo const *ni = net.second.get();
auto new_clock = clock_nets.end();
auto clock_wire_bel = clock_io(ctx, ni->driver);
auto clock_wire_bel = clock_src(ctx, ni->driver);
if (clock_wire_bel.first != WireId()) {
clock_nets.emplace_back(net.first);
new_clock = --clock_nets.end();
new_clock->clock_io_wire = clock_wire_bel.first;
new_clock->clock_io_bel = clock_wire_bel.second;
new_clock->clock_wire = clock_wire_bel.first;
new_clock->clock_bel = clock_wire_bel.second;
}
for (auto const &user : ni->users) {
if (is_clock_port(user)) {
@ -86,8 +92,8 @@ void GowinGlobalRouter::gather_clock_nets(Context *ctx, std::vector<globalnet_t>
if (ctx->verbose) {
for (auto const &net : clock_nets) {
log_info(" Net:%s, ports:%d, io:%s\n", net.name.c_str(ctx), net.clock_ports,
net.clock_io_wire == WireId() ? "No" : net.clock_io_wire.c_str(ctx));
log_info(" Net:%s, ports:%d, clock source:%s\n", net.name.c_str(ctx), net.clock_ports,
net.clock_wire == WireId() ? "No" : net.clock_wire.c_str(ctx));
}
}
}
@ -238,33 +244,35 @@ void GowinGlobalRouter::route_net(Context *ctx, globalnet_t const &net)
}
used_pips.insert(spine_pip_id);
// >>> SPINExx <- IO
// >>> SPINExx <- Src
dstWire = ctx->getPipSrcWire(spine_pip_id);
dstWireInfo = ctx->wire_info(dstWire);
PipId io_pip_id = PipId();
PipId src_pip_id = PipId();
for (auto const uphill_pip : ctx->getPipsUphill(dstWire)) {
if (ctx->getPipSrcWire(uphill_pip) == net.clock_io_wire) {
io_pip_id = uphill_pip;
if (ctx->getPipSrcWire(uphill_pip) == net.clock_wire) {
src_pip_id = uphill_pip;
}
}
NPNR_ASSERT(io_pip_id != PipId());
NPNR_ASSERT(src_pip_id != PipId());
if (ctx->verbose) {
log_info(" IO Pip:%s\n", io_pip_id.c_str(ctx));
log_info(" Src Pip:%s\n", src_pip_id.c_str(ctx));
}
// if already routed
if (used_pips.count(io_pip_id)) {
if (used_pips.count(src_pip_id)) {
if (ctx->verbose) {
log_info(" ^routed already^\n");
}
continue;
}
used_pips.insert(io_pip_id);
used_pips.insert(src_pip_id);
}
log_info(" Net %s is routed.\n", net.name.c_str(ctx));
if (!ctx->net_info(net.name).users.empty()) {
for (auto const pip : used_pips) {
ctx->bindPip(pip, &ctx->net_info(net.name), STRENGTH_LOCKED);
}
ctx->bindWire(net.clock_io_wire, &ctx->net_info(net.name), STRENGTH_LOCKED);
ctx->bindWire(net.clock_wire, &ctx->net_info(net.name), STRENGTH_LOCKED);
}
}
void GowinGlobalRouter::route_globals(Context *ctx)
@ -289,16 +297,21 @@ void GowinGlobalRouter::mark_globals(Context *ctx)
int max_clock = 3, cur_clock = -1;
for (auto &net : clock_nets) {
// XXX only IO clock for now
if (net.clock_io_wire == WireId()) {
log_info(" Non IO clock, skip %s.\n", net.name.c_str(ctx));
if (net.clock_wire == WireId()) {
log_info(" Non clock source, skip %s.\n", net.name.c_str(ctx));
continue;
}
if (++cur_clock >= max_clock) {
log_info(" No more clock wires left, skip the remaining nets.\n");
break;
}
if (ctx->net_info(net.name).users.empty()) {
--cur_clock;
net.clock = -1;
} else {
net.clock = cur_clock;
BelInfo &bi = ctx->bel_info(net.clock_io_bel);
}
BelInfo &bi = ctx->bel_info(net.clock_bel);
bi.gb = true;
nets.emplace_back(net);
}

18
gowin/globals.h
View File

@ -39,32 +39,32 @@ class GowinGlobalRouter
{
IdString name;
int clock_ports;
BelId clock_io_bel;
WireId clock_io_wire; // IO wire if there is one
BelId clock_bel;
WireId clock_wire; // clock wire if there is one
int clock; // clock #
globalnet_t()
{
name = IdString();
clock_ports = 0;
clock_io_bel = BelId();
clock_io_wire = WireId();
clock_bel = BelId();
clock_wire = WireId();
clock = -1;
}
globalnet_t(IdString _name)
{
name = _name;
clock_ports = 0;
clock_io_bel = BelId();
clock_io_wire = WireId();
clock_bel = BelId();
clock_wire = WireId();
clock = -1;
}
// sort
bool operator<(const globalnet_t &other) const
{
if ((clock_io_wire != WireId()) ^ (other.clock_io_wire != WireId())) {
return !(clock_io_wire != WireId());
if ((clock_wire != WireId()) ^ (other.clock_wire != WireId())) {
return !(clock_wire != WireId());
}
return clock_ports < other.clock_ports;
}
@ -76,7 +76,7 @@ class GowinGlobalRouter
std::vector<globalnet_t> nets;
bool is_clock_port(PortRef const &user);
std::pair<WireId, BelId> clock_io(Context *ctx, PortRef const &driver);
std::pair<WireId, BelId> clock_src(Context *ctx, PortRef const &driver);
void gather_clock_nets(Context *ctx, std::vector<globalnet_t> &clock_nets);
IdString route_to_non_clock_port(Context *ctx, WireId const dstWire, int clock, pool<IdString> &used_pips,
pool<IdString> &undo_wires);

10
gowin/main.cc
View File

@ -51,7 +51,8 @@ po::options_description GowinCommandHandler::getArchOptions()
specific.add_options()("device", po::value<std::string>(), "device name");
specific.add_options()("family", po::value<std::string>(), "family name");
specific.add_options()("cst", po::value<std::string>(), "physical constraints file");
specific.add_options()("enable-globals", "separate routing of the clocks");
specific.add_options()("enable-globals", "enable separate routing of the clocks");
specific.add_options()("disable-globals", "disable separate routing of the clocks");
specific.add_options()("enable-auto-longwires", "automatic detection and routing of long wires");
return specific;
}
@ -84,11 +85,10 @@ std::unique_ptr<Context> GowinCommandHandler::createContext(dict<std::string, Pr
auto ctx = std::unique_ptr<Context>(new Context(chipArgs));
// routing options
// the default values will change in the future
ctx->settings[ctx->id("arch.enable-globals")] = 0;
ctx->settings[ctx->id("arch.enable-auto-longwires")] = 0;
if (vm.count("enable-globals")) {
ctx->settings[ctx->id("arch.enable-globals")] = 1;
ctx->settings[ctx->id("arch.enable-auto-longwires")] = 0;
if (vm.count("disable-globals")) {
ctx->settings[ctx->id("arch.enable-globals")] = 0;
}
if (vm.count("enable-auto-longwires")) {
ctx->settings[ctx->id("arch.enable-auto-longwires")] = 1;