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ice40: Reworking placement legalisation to allow integration with SA placer

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-06-29 12:02:34 +02:00
parent 960c650478
commit c18b7b3f6e
4 changed files with 125 additions and 41 deletions
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9
common/util.h
View File

@ -75,6 +75,15 @@ template <typename K> std::set<K> sorted(const std::unordered_set<K> &orig)
return retVal;
};
// Return a net if port exists, or nullptr
inline const NetInfo *get_net_or_empty(const CellInfo *cell, const IdString port)
{
auto found = cell->ports.find(port);
if (found != cell->ports.end())
return found->second.net;
else
return nullptr;
};
NEXTPNR_NAMESPACE_END
#endif

9
ice40/arch_place.cc
View File

@ -24,15 +24,6 @@
NEXTPNR_NAMESPACE_BEGIN
static const NetInfo *get_net_or_empty(const CellInfo *cell, const IdString port)
{
auto found = cell->ports.find(port);
if (found != cell->ports.end())
return found->second.net;
else
return nullptr;
};
bool Arch::logicCellsCompatible(const std::vector<const CellInfo *> &cells) const
{
bool dffs_exist = false, dffs_neg = false;

10
ice40/main.cc
View File

@ -126,16 +126,18 @@ int main(int argc, char *argv[])
if (vm.count("help") || argc == 1) {
help:
std::cout << boost::filesystem::basename(argv[0]) << " -- Next Generation Place and Route (git "
"sha1 " GIT_COMMIT_HASH_STR ")\n";
std::cout << boost::filesystem::basename(argv[0])
<< " -- Next Generation Place and Route (git "
"sha1 " GIT_COMMIT_HASH_STR ")\n";
std::cout << "\n";
std::cout << options << "\n";
return argc != 1;
}
if (vm.count("version")) {
std::cout << boost::filesystem::basename(argv[0]) << " -- Next Generation Place and Route (git "
"sha1 " GIT_COMMIT_HASH_STR ")\n";
std::cout << boost::filesystem::basename(argv[0])
<< " -- Next Generation Place and Route (git "
"sha1 " GIT_COMMIT_HASH_STR ")\n";
return 1;
}

138
ice40/place_legaliser.cc
View File

@ -87,6 +87,31 @@ static void get_chain_midpoint(const Context *ctx, const CellChain &chain, float
y = total_y / N;
}
static int get_cell_evilness(const Context *ctx, const CellInfo *cell)
{
// This returns how "evil" a logic cell is, and thus how likely it is to be ripped up
// during logic tile legalisation
int score = 0;
if (get_net_or_empty(cell, ctx->id("I0")))
++score;
if (get_net_or_empty(cell, ctx->id("I1")))
++score;
if (get_net_or_empty(cell, ctx->id("I2")))
++score;
if (get_net_or_empty(cell, ctx->id("I3")))
++score;
if (bool_or_default(cell->params, ctx->id("DFF_ENABLE"))) {
const NetInfo *cen = get_net_or_empty(cell, ctx->id("CEN")), *sr = get_net_or_empty(cell, ctx->id("SR"));
if (cen)
score += 10;
if (sr)
score += 10;
if (bool_or_default(cell->params, ctx->id("NEG_CLK")))
score += 5;
}
return score;
}
class PlacementLegaliser
{
public:
@ -99,6 +124,8 @@ class PlacementLegaliser
bool legalised_carries = legalise_carries();
if (!legalised_carries && !ctx->force)
return false;
legalise_others();
legalise_logic_tiles();
bool replaced_cells = replace_cells();
return legalised_carries && replaced_cells;
}
@ -127,34 +154,29 @@ class PlacementLegaliser
bool legalise_carries()
{
std::vector<CellChain> carry_chains = find_chains(
ctx,
[](const Context *ctx, const CellInfo *cell) {
return is_lc(ctx, cell);
},
[](const Context *ctx, const
std::vector<CellChain> carry_chains =
find_chains(ctx, [](const Context *ctx, const CellInfo *cell) { return is_lc(ctx, cell); },
[](const Context *ctx, const
CellInfo *cell) {
CellInfo *carry_prev =
net_driven_by(ctx, cell->ports.at(ctx->id("CIN")).net, is_lc, ctx->id("COUT"));
if (carry_prev != nullptr)
return carry_prev;
/*CellInfo *i3_prev = net_driven_by(ctx, cell->ports.at(ctx->id("I3")).net, is_lc, ctx->id("COUT"));
if (i3_prev != nullptr)
return i3_prev;*/
return (CellInfo *)nullptr;
},
[](const Context *ctx, const CellInfo *cell) {
CellInfo *carry_next =
net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_lc, ctx->id("CIN"), false);
if (carry_next != nullptr)
return carry_next;
/*CellInfo *i3_next =
net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_lc, ctx->id("I3"), false);
if (i3_next != nullptr)
return i3_next;*/
return (CellInfo *)nullptr;
});
CellInfo *cell) {
CellInfo *carry_prev =
net_driven_by(ctx, cell->ports.at(ctx->id("CIN")).net, is_lc, ctx->id("COUT"));
if (carry_prev != nullptr)
return carry_prev;
/*CellInfo *i3_prev = net_driven_by(ctx, cell->ports.at(ctx->id("I3")).net, is_lc,
ctx->id("COUT")); if (i3_prev != nullptr) return i3_prev;*/
return (CellInfo *)nullptr;
},
[](const Context *ctx, const CellInfo *cell) {
CellInfo *carry_next = net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_lc,
ctx->id("CIN"), false);
if (carry_next != nullptr)
return carry_next;
/*CellInfo *i3_next =
net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_lc, ctx->id("I3"),
false); if (i3_next != nullptr) return i3_next;*/
return (CellInfo *)nullptr;
});
std::unordered_set<IdString> chained;
for (auto &base_chain : carry_chains) {
for (auto c : base_chain.cells)
@ -164,7 +186,8 @@ class PlacementLegaliser
// for correct processing
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (chained.find(cell.first) == chained.end() && is_lc(ctx, ci) && bool_or_default(ci->params, ctx->id("CARRY_ENABLE"))) {
if (chained.find(cell.first) == chained.end() && is_lc(ctx, ci) &&
bool_or_default(ci->params, ctx->id("CARRY_ENABLE"))) {
CellChain sChain;
sChain.cells.push_back(ci);
chained.insert(cell.first);
@ -400,6 +423,65 @@ class PlacementLegaliser
return ctx->cells[name].get();
}
// Legalise logic tiles
void legalise_logic_tiles()
{
int width = ctx->chip_info->width, height = ctx->chip_info->height;
for (int x = 1; x < width; x++) {
for (int y = 1; y < height; y++) {
BelId tileBel = logic_bels.at(x).at(y).at(0).first;
if (tileBel != BelId()) {
bool changed = true;
while (!ctx->isBelLocationValid(tileBel) && changed) {
changed = false;
int max_score = 0;
CellInfo *target = nullptr;
for (int z = 0; z < 8; z++) {
BelId bel = logic_bels.at(x).at(y).at(z).first;
IdString cell = ctx->getBoundBelCell(bel);
if (cell != IdString()) {
CellInfo *ci = ctx->cells.at(cell).get();
if (ci->belStrength >= STRENGTH_STRONG)
continue;
int score = get_cell_evilness(ctx, ci);
if (score > max_score) {
max_score = score;
target = ci;
}
}
}
if (target != nullptr) {
ctx->unbindBel(target->bel);
rippedCells.insert(target->name);
changed = true;
}
}
}
}
}
}
// Legalise other tiles
void legalise_others()
{
std::vector<CellInfo *> legalised_others;
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (!is_lc(ctx, ci)) {
if (ci->belStrength < STRENGTH_STRONG && ci->bel != BelId()) {
if (!ctx->isValidBelForCell(ci, ci->bel)) {
place_single_cell(ctx, ci, true);
}
legalised_others.push_back(ci);
}
}
}
// Lock all these cells now, we don't need to move them in SA (don't lock during legalise placement
// so legalise placement can rip up in case of gbuf contention etc)
for (auto cell : legalised_others)
cell->belStrength = STRENGTH_STRONG;
}
// Replace ripped-up cells
bool replace_cells()
{