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interchange: Improve search for PAD-attached bels

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Signed-off-by: gatecat <gatecat@ds0.me>
This commit is contained in:
gatecat 2021-07-06 10:13:50 +01:00
parent 6edc11de4d
commit f64d06fa02
2 changed files with 32 additions and 41 deletions
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3
fpga_interchange/arch.h
View File

@ -708,7 +708,8 @@ struct Arch : ArchAPI<ArchRanges>
// ------------------------------------------------- // -------------------------------------------------
void place_iobufs(WireId pad_wire, NetInfo *net, const pool<CellInfo *, hash_ptr_ops> &tightly_attached_bels, void place_iobufs(WireId pad_wire, NetInfo *net,
const dict<CellInfo *, IdString, hash_ptr_ops> &tightly_attached_bels,
pool<CellInfo *, hash_ptr_ops> *placed_cells); pool<CellInfo *, hash_ptr_ops> *placed_cells);
void pack_ports(); void pack_ports();

70
fpga_interchange/arch_pack_io.cc
View File

@ -27,7 +27,7 @@
NEXTPNR_NAMESPACE_BEGIN NEXTPNR_NAMESPACE_BEGIN
namespace { namespace {
bool search_routing_for_placement(Arch *arch, WireId start_wire, CellInfo *cell, IdString cell_pin) bool search_routing_for_placement(Arch *arch, WireId start_wire, CellInfo *cell, IdString cell_pin, bool downhill)
{ {
std::queue<WireId> visit_queue; std::queue<WireId> visit_queue;
pool<WireId> already_visited; pool<WireId> already_visited;
@ -51,54 +51,44 @@ bool search_routing_for_placement(Arch *arch, WireId start_wire, CellInfo *cell,
// Bel pin doesn't match // Bel pin doesn't match
arch->unbindBel(bp.bel); arch->unbindBel(bp.bel);
} }
for (auto pip : arch->getPipsDownhill(next)) { auto do_visit = [&](PipId pip) {
WireId dst = arch->getPipDstWire(pip); WireId dst = downhill ? arch->getPipDstWire(pip) : arch->getPipSrcWire(pip);
if (already_visited.count(dst)) if (already_visited.count(dst))
continue; return;
if (!arch->is_site_wire(dst) && arch->get_wire_category(dst) == WIRE_CAT_GENERAL) if (!arch->is_site_wire(dst) && arch->get_wire_category(dst) == WIRE_CAT_GENERAL)
continue; // this pass only considers dedicated routing return; // this pass only considers dedicated routing
visit_queue.push(dst); visit_queue.push(dst);
already_visited.insert(dst); already_visited.insert(dst);
};
if (downhill) {
for (auto pip : arch->getPipsDownhill(next))
do_visit(pip);
} else {
for (auto pip : arch->getPipsUphill(next))
do_visit(pip);
} }
} }
return false; return false;
} }
} // namespace } // namespace
void Arch::place_iobufs(WireId pad_wire, NetInfo *net, const pool<CellInfo *, hash_ptr_ops> &tightly_attached_bels, void Arch::place_iobufs(WireId pad_wire, NetInfo *net,
const dict<CellInfo *, IdString, hash_ptr_ops> &tightly_attached_bels,
pool<CellInfo *, hash_ptr_ops> *placed_cells) pool<CellInfo *, hash_ptr_ops> *placed_cells)
{ {
for (BelPin bel_pin : getWireBelPins(pad_wire)) { Context *ctx = getCtx();
BelId bel = bel_pin.bel; for (auto cell_port : tightly_attached_bels) {
for (CellInfo *cell : tightly_attached_bels) { bool downhill = (cell_port.first->ports.at(cell_port.second).type != PORT_OUT);
if (isValidBelForCellType(cell->type, bel)) { if (search_routing_for_placement(this, pad_wire, cell_port.first, cell_port.second, downhill)) {
NPNR_ASSERT(cell->bel == BelId()); if (ctx->verbose)
NPNR_ASSERT(placed_cells->count(cell) == 0); log_info("Placed IO cell %s:%s at %s.\n", ctx->nameOf(cell_port.first),
ctx->nameOf(cell_port.first->type), ctx->nameOfBel(cell_port.first->bel));
bindBel(bel, cell, STRENGTH_FIXED);
placed_cells->emplace(cell);
IdString cell_port;
for (auto pin_pair : cell->cell_bel_pins) {
for (IdString a_bel_pin : pin_pair.second) {
if (a_bel_pin == bel_pin.pin) {
NPNR_ASSERT(cell_port == IdString());
cell_port = pin_pair.first;
}
}
}
NPNR_ASSERT(cell_port != IdString());
const PortInfo &port = cell->ports.at(cell_port);
NPNR_ASSERT(port.net == net);
}
} }
} }
// Also try, on a best-effort basis, to preplace other cells in the macro based on downstream routing. This is // Also try, on a best-effort basis, to preplace other cells in the macro based on downstream routing. This is
// needed for the split INBUF+IBUFCTRL arrangement in the UltraScale+, as just placing the INBUF will result in an // needed for the split INBUF+IBUFCTRL arrangement in the UltraScale+, as just placing the INBUF will result in an
// unrouteable site and illegal placement. // unrouteable site and illegal placement.
Context *ctx = getCtx();
std::queue<CellInfo *> place_queue; std::queue<CellInfo *> place_queue;
for (auto pc : *placed_cells) for (auto pc : *placed_cells)
place_queue.push(pc); place_queue.push(pc);
@ -119,7 +109,7 @@ void Arch::place_iobufs(WireId pad_wire, NetInfo *net, const pool<CellInfo *, ha
if (usr.cell->bel != BelId() || usr.cell->macro_parent != cursor->macro_parent) if (usr.cell->bel != BelId() || usr.cell->macro_parent != cursor->macro_parent)
continue; continue;
// Try and place using dedicated routing // Try and place using dedicated routing
if (search_routing_for_placement(this, src_wire, usr.cell, usr.port)) { if (search_routing_for_placement(this, src_wire, usr.cell, usr.port, true)) {
// Successful // Successful
placed_cells->insert(usr.cell); placed_cells->insert(usr.cell);
place_queue.push(usr.cell); place_queue.push(usr.cell);
@ -200,34 +190,34 @@ void Arch::pack_ports()
for (auto port_pair : port_cells) { for (auto port_pair : port_cells) {
IdString port_name = port_pair.first; IdString port_name = port_pair.first;
CellInfo *port_cell = port_pair.second; CellInfo *port_cell = port_pair.second;
pool<CellInfo *, hash_ptr_ops> tightly_attached_bels; dict<CellInfo *, IdString, hash_ptr_ops> tightly_attached_bels;
for (auto port_pair : port_cell->ports) { for (auto port_pair : port_cell->ports) {
const PortInfo &port_info = port_pair.second; const PortInfo &port_info = port_pair.second;
const NetInfo *net = port_info.net; const NetInfo *net = port_info.net;
if (net->driver.cell) { if (net->driver.cell) {
tightly_attached_bels.emplace(net->driver.cell); tightly_attached_bels.emplace(net->driver.cell, net->driver.port);
} }
for (const PortRef &port_ref : net->users) { for (const PortRef &port_ref : net->users) {
if (port_ref.cell) { if (port_ref.cell) {
tightly_attached_bels.emplace(port_ref.cell); tightly_attached_bels.emplace(port_ref.cell, port_ref.port);
} }
} }
} }
if (getCtx()->verbose) { if (getCtx()->verbose) {
log_info("Tightly attached BELs for port %s\n", port_name.c_str(getCtx())); log_info("Tightly attached BELs for port %s\n", port_name.c_str(getCtx()));
for (CellInfo *cell : tightly_attached_bels) { for (auto cell_port : tightly_attached_bels) {
log_info(" - %s : %s\n", cell->name.c_str(getCtx()), cell->type.c_str(getCtx())); log_info(" - %s : %s\n", cell_port.first->name.c_str(getCtx()), cell_port.first->type.c_str(getCtx()));
} }
} }
NPNR_ASSERT(tightly_attached_bels.erase(port_cell) == 1); NPNR_ASSERT(tightly_attached_bels.erase(port_cell) == 1);
pool<IdString> cell_types_in_io_group; pool<IdString> cell_types_in_io_group;
for (CellInfo *cell : tightly_attached_bels) { for (auto cell_port : tightly_attached_bels) {
NPNR_ASSERT(port_cells.find(cell->name) == port_cells.end()); NPNR_ASSERT(port_cells.find(cell_port.first->name) == port_cells.end());
cell_types_in_io_group.emplace(cell->type); cell_types_in_io_group.emplace(cell_port.first->type);
} }
// Get possible placement locations for tightly coupled BELs with // Get possible placement locations for tightly coupled BELs with