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Merge pull request #1106 from YosysHQ/gatecat/fab_carry

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fabulous: Add support for packing carry chains
This commit is contained in:
myrtle 2023-02-21 15:47:17 +01:00 committed by GitHub
commit 0c4e0d4312
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3 changed files with 122 additions and 10 deletions
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3
generic/viaduct/fabulous/constids.inc
View File

@ -82,6 +82,7 @@ X(EN)
X(BEL)
X(PAD)
X(LUT1)
X(LUT4_HA)
X(BelBegin)
X(BelEnd)
@ -96,3 +97,5 @@ X(M_AB)
X(M_AD)
X(M_EF)
X(M_AH)
X(I0MUX)

4
generic/viaduct/fabulous/fasm.cc
View File

@ -107,11 +107,15 @@ struct FabFasmWriter
}
}
void add_feature(const std::string &name) { out << prefix << name << std::endl; }
void write_logic(const CellInfo *lc)
{
prefix = format_name(ctx->getBelName(lc->bel)) + ".";
if (lc->type.in(id_FABULOUS_LC, id_FABULOUS_COMB)) {
write_int_vector_param(lc, "INIT", 0U, 1U << cfg.clb.lut_k); // todo lut depermute and thru
if (bool_or_default(lc->params, id_I0MUX, false))
add_feature("IOmux"); // typo in FABulous?
}
if (lc->type == id_FABULOUS_LC) {
write_bool(lc, "FF");

125
generic/viaduct/fabulous/pack.cc
View File

@ -25,6 +25,8 @@
#include "viaduct_constids.h"
#include "viaduct_helpers.h"
#include "validity_check.h"
NEXTPNR_NAMESPACE_BEGIN
namespace {
@ -36,6 +38,7 @@ struct FabulousPacker
dict<IdString, unsigned> lut_types;
std::vector<IdString> lut_inputs;
CellTagger cell_tags;
FabulousPacker(Context *ctx, const FabricConfig &cfg) : ctx(ctx), cfg(cfg)
{
@ -44,6 +47,8 @@ struct FabulousPacker
lut_types[ctx->idf("LUT%d", i + 1)] = i + 1;
lut_inputs.push_back(ctx->idf("I%d", i));
}
if (cfg.clb.lut_k == 4)
lut_types[id_LUT4_HA] = 4; // special case for now
h.init(ctx);
}
@ -77,6 +82,16 @@ struct FabulousPacker
}
}
void assign_lc_info()
{
int flat_index = 0;
for (auto &cell : ctx->cells) {
cell.second->flat_index = flat_index++;
if (cell.second->type == id_FABULOUS_LC)
cell_tags.assign_for(ctx, cfg, cell.second.get());
}
}
// Two-stage flipflop packing. First convert all the random primitives into a much easier-to-handle FABULOUS_FF
// Then for split-LC mode, cluster it to connected LUTs; separate-LC mode, pack it into a connected or new LC
@ -179,9 +194,34 @@ struct FabulousPacker
}
}
bool check_cluster_legality(CellInfo *lc) {
if (lc->cluster == ClusterId())
return true;
CLBState test_clb(cfg.clb);
auto process_cluster_cell = [&](CellInfo *ci) {
if (ci->constr_y != lc->constr_y)
return;
if (ci->type == id_FABULOUS_LC) {
NPNR_ASSERT(ci->constr_z >= 0 && ci->constr_z < int(cfg.clb.lc_per_clb));
test_clb.lc_comb[ci->constr_z] = ci;
} else if (ci->type.in(id_FABULOUS_MUX2, id_FABULOUS_MUX4, id_FABULOUS_MUX8)) {
int mux_z = (ci->constr_z - cfg.clb.lc_per_clb - 1);
NPNR_ASSERT(mux_z >= 0 && mux_z < int(cfg.clb.lc_per_clb));
test_clb.mux[mux_z] = ci;
}
// TODO: non-split MODE
};
CellInfo *root = ctx->getClusterRootCell(lc->cluster);
process_cluster_cell(root);
for (auto child : root->constr_children)
process_cluster_cell(child);
return test_clb.check_validity(cfg.clb, cell_tags);
}
void pack_ffs()
{
pool<IdString> to_delete;
assign_lc_info();
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (ci->type != id_FABULOUS_FF)
@ -194,30 +234,43 @@ struct FabulousPacker
continue;
if (!cfg.clb.split_lc && d->users.entries() > 1)
continue; // TODO: could also resolve by duplicating LUT
if (drv->cluster != ClusterId()) {
// TODO: actually we can pack these often, we just have to be more careful to check control sets
continue;
}
// we can pack them together
if (cfg.clb.split_lc) {
// create/modify cluster and add constraints. copy from an arch where we do this already...
NPNR_ASSERT_FALSE("unimplemented");
} else {
to_delete.insert(ci->name);
// this connection is packed inside the LC
ci->disconnectPort(id_D);
drv->disconnectPort(id_O);
// move other ports/params
// move config ports/params, these affect control set for the legality set
ci->movePortTo(id_CLK, drv, id_CLK);
ci->movePortTo(id_SR, drv, id_SR);
ci->movePortTo(id_EN, drv, id_EN);
ci->movePortTo(id_O, drv, id_Q);
drv->params[id_NEG_CLK] = ci->params[id_NEG_CLK];
drv->params[id_ASYNC_SR] = ci->params[id_ASYNC_SR];
drv->params[id_SET_NORESET] = ci->params[id_SET_NORESET];
drv->params[id_FF] = 1;
// update tags for this cluster checks
cell_tags.assign_for(ctx, cfg, drv);
if (drv->cluster != ClusterId()) {
if (!check_cluster_legality(drv)) {
// If packing wasn't legal; revert half-finished move
for (auto p : {id_NEG_CLK, id_SR, id_EN, id_FF})
drv->params.erase(p);
drv->movePortTo(id_CLK, ci, id_CLK);
drv->movePortTo(id_SR, ci, id_SR);
drv->movePortTo(id_EN, ci, id_EN);
// revert tag changes too for this cluster checks
cell_tags.assign_for(ctx, cfg, drv);
continue;
}
}
// this connection is packed inside the LC
to_delete.insert(ci->name);
ci->movePortTo(id_O, drv, id_Q);
ci->disconnectPort(id_D);
drv->disconnectPort(id_O);
for (auto &attr : ci->attrs)
drv->attrs[attr.first] = attr.second;
// update tags for future cluster checks
cell_tags.assign_for(ctx, cfg, drv);
}
}
for (auto del : to_delete)
@ -279,6 +332,57 @@ struct FabulousPacker
h.remove_nextpnr_iobs(top_ports);
}
void constrain_carries()
{
std::vector<CellInfo *> carry_roots;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (!ci->type.in(id_FABULOUS_LC, id_FABULOUS_COMB))
continue;
if (!ci->getPort(id_Ci) && ci->getPort(id_Co))
carry_roots.push_back(ci);
else if (ci->getPort(id_Ci) && ci->getPort(id_Ci)->driver.cell) {
auto &drv = ci->getPort(id_Ci)->driver;
if (drv.port != id_Co || !drv.cell->type.in(id_FABULOUS_LC, id_FABULOUS_COMB))
log_error("Carry cell '%s' has Ci driven by illegal port '%s.%s'\n", ctx->nameOf(ci),
ctx->nameOf(drv.cell), ctx->nameOf(drv.port));
}
}
for (auto root : carry_roots) {
CellInfo *cursor = root;
int dy = 0, dz = 0;
while (true) {
// create cluster
cursor->cluster = root->name;
cursor->constr_z = dz;
cursor->constr_abs_z = true;
if (cursor != root) {
cursor->constr_x = 0;
cursor->constr_y = -dy;
root->constr_children.push_back(cursor);
}
NetInfo *co = cursor->getPort(id_Co);
if (co && !co->users.empty()) {
if (co->users.entries() > 1)
log_error("Carry cell '%s' has illegal multiple fanout on Co net '%s'\n", ctx->nameOf(cursor),
ctx->nameOf(co));
auto &usr = *(co->users.begin());
if (usr.port != id_Ci || !usr.cell->type.in(id_FABULOUS_LC, id_FABULOUS_COMB))
log_error("Carry cell '%s' has illegal fanout '%s.%s' on Co net '%s'\n", ctx->nameOf(cursor),
ctx->nameOf(usr.cell), ctx->nameOf(usr.port), ctx->nameOf(co));
cursor = usr.cell;
} else {
break;
}
++dz;
if (dz == int(cfg.clb.lc_per_clb)) {
dz = 0;
++dy;
}
}
}
}
void run()
{
update_bel_attrs();
@ -287,6 +391,7 @@ struct FabulousPacker
pack_luts();
pack_muxes();
prepare_ffs();
constrain_carries();
pack_ffs();
}
};