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ecp5: Pre-place PLLs and use dedicated routes into globals

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Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2018-11-30 16:09:56 +00:00
parent fc08856537
commit 5ddf99cf5d
2 changed files with 59 additions and 2 deletions
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6
ecp5/globals.cc
View File

@ -298,6 +298,8 @@ class Ecp5GlobalRouter
} else {
// Check for dedicated routing
if (has_short_route(ctx->getBelPinWire(drv_bel, drv.port), ctx->getBelPinWire(dcc->bel, id_CLKI))) {
// log_info("dedicated route %s -> %s\n", ctx->getWireName(ctx->getBelPinWire(drv_bel,
// drv.port)).c_str(ctx), ctx->getBelName(dcc->bel).c_str(ctx));
return 0;
}
// Driver is locked
@ -308,7 +310,7 @@ class Ecp5GlobalRouter
}
// Return true if a short (<5) route exists between two wires
bool has_short_route(WireId src, WireId dst, int thresh = 5)
bool has_short_route(WireId src, WireId dst, int thresh = 7)
{
std::queue<WireId> visit;
std::unordered_map<WireId, PipId> backtrace;
@ -316,7 +318,7 @@ class Ecp5GlobalRouter
WireId cursor;
while (true) {
if (visit.empty() || visit.size() > 1000) {
if (visit.empty() || visit.size() > 10000) {
// log_info ("dist %s -> %s = inf\n", ctx->getWireName(src).c_str(ctx),
// ctx->getWireName(dst).c_str(ctx));
return false;

55
ecp5/pack.cc
View File

@ -1323,6 +1323,60 @@ class Ecp5Packer
}
}
// Preplace PLL
void preplace_plls()
{
std::set<BelId> available_plls;
for (auto bel : ctx->getBels()) {
if (ctx->getBelType(bel) == id_EHXPLLL && ctx->checkBelAvail(bel))
available_plls.insert(bel);
}
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (ci->type == id_EHXPLLL && ci->attrs.count(ctx->id("BEL")))
available_plls.erase(ctx->getBelByName(ctx->id(ci->attrs.at(ctx->id("BEL")))));
}
// Place PLL connected to fixed drivers such as IO close to their source
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (ci->type == id_EHXPLLL && !ci->attrs.count(ctx->id("BEL"))) {
const NetInfo *drivernet = net_or_nullptr(ci, id_CLKI);
if (drivernet == nullptr || drivernet->driver.cell == nullptr)
continue;
const CellInfo *drivercell = drivernet->driver.cell;
if (!drivercell->attrs.count(ctx->id("BEL")))
continue;
BelId drvbel = ctx->getBelByName(ctx->id(drivercell->attrs.at(ctx->id("BEL"))));
Loc drvloc = ctx->getBelLocation(drvbel);
BelId closest_pll;
int closest_distance = std::numeric_limits<int>::max();
for (auto bel : available_plls) {
Loc pllloc = ctx->getBelLocation(bel);
int distance = std::abs(drvloc.x - pllloc.x) + std::abs(drvloc.y - pllloc.y);
if (distance < closest_distance) {
closest_pll = bel;
closest_distance = distance;
}
}
if (closest_pll == BelId())
log_error("failed to place PLL '%s'\n", ci->name.c_str(ctx));
available_plls.erase(closest_pll);
ci->attrs[ctx->id("BEL")] = ctx->getBelName(closest_pll).str(ctx);
}
}
// Place PLLs driven by logic, etc, randomly
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (ci->type == id_EHXPLLL && !ci->attrs.count(ctx->id("BEL"))) {
if (available_plls.empty())
log_error("failed to place PLL '%s'\n", ci->name.c_str(ctx));
BelId next_pll = *(available_plls.begin());
available_plls.erase(next_pll);
ci->attrs[ctx->id("BEL")] = ctx->getBelName(next_pll).str(ctx);
}
}
}
public:
void pack()
{
@ -1330,6 +1384,7 @@ class Ecp5Packer
pack_ebr();
pack_dsps();
pack_dcus();
preplace_plls();
pack_constants();
pack_dram();
pack_carries();