caiyu/nextpnr
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

nexus: IO pre-packing

Browse Source 
Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2020-10-12 11:41:26 +01:00
parent 69b449c875
commit 518ead2e2d
2 changed files with 67 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
common/util.h
View File

@ -112,6 +112,15 @@ template <typename K, typename V> std::map<K, V *> sorted(const std::unordered_m
return retVal;
};
// Wrap an unordered_map, and allow it to be iterated over sorted by key
template <typename K, typename V> std::map<K, V &> sorted_ref(std::unordered_map<K, V> &orig)
{
std::map<K, V &> retVal;
for (auto &item : orig)
retVal.emplace(std::make_pair(item.first, std::ref(item.second)));
return retVal;
};
// Wrap an unordered_set, and allow it to be iterated over sorted by key
template <typename K> std::set<K> sorted(const std::unordered_set<K> &orig)
{

58
nexus/pack.cc
View File

@ -473,6 +473,64 @@ struct NexusPacker
}
}
void prepare_io()
{
// Find the actual IO buffer corresponding to a port; and copy attributes across to it
// Note that this relies on Yosys to do IO buffer inference, to match vendor tooling behaviour
// In all cases the nextpnr-inserted IO buffers are removed as redundant.
for (auto &port : sorted_ref(ctx->ports)) {
if (!ctx->cells.count(port.first))
log_error("Port '%s' doesn't seem to have a corresponding top level IO\n", ctx->nameOf(port.first));
CellInfo *ci = ctx->cells.at(port.first).get();
PortRef top_port;
top_port.cell = nullptr;
bool is_npnr_iob = false;
if (ci->type == ctx->id("$nextpnr_ibuf") || ci->type == ctx->id("$nextpnr_iobuf")) {
// Might have an input buffer (IB etc) connected to it
is_npnr_iob = true;
NetInfo *o = get_net_or_empty(ci, id_O);
if (o == nullptr)
;
else if (o->users.size() > 1)
log_error("Top level '%s' has multiple input buffers\n", ctx->nameOf(port.first));
else if (o->users.size() == 1)
top_port = o->users.at(0);
}
if (ci->type == ctx->id("$nextpnr_obuf") || ci->type == ctx->id("$nextpnr_iobuf")) {
// Might have an output buffer (OB etc) connected to it
is_npnr_iob = true;
NetInfo *i = get_net_or_empty(ci, id_I);
if (i == nullptr && i->driver.cell != nullptr) {
if (top_port.cell != nullptr)
log_error("Top level '%s' has multiple input/output buffers\n", ctx->nameOf(port.first));
top_port = i->driver;
}
}
if (!is_npnr_iob)
log_error("Port '%s' doesn't seem to have a corresponding top level IO (internal cell type mismatch)\n",
ctx->nameOf(port.first));
if (top_port.cell == nullptr) {
log_info("Trimming port '%s' as it is unused.\n", ctx->nameOf(port.first));
} else {
// Copy attributes to real IO buffer
if (ctx->io_attr.count(port.first)) {
for (auto &kv : ctx->io_attr.at(port.first)) {
top_port.cell->attrs[kv.first] = kv.second;
}
}
// Make sure that top level net is set correctly
port.second.net = top_port.cell->ports.at(top_port.port).net;
}
// Now remove the nextpnr-inserted buffer
disconnect_port(ctx, ci, id_I);
disconnect_port(ctx, ci, id_O);
ctx->cells.erase(port.first);
}
}
void pack_io()
{
for (auto cell : sorted(ctx->cells)) {