riscv
/
yosys
mirror of https://github.com/YosysHQ/yosys.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
yosys/passes/techmap/shregmap.cc

754 lines
22 KiB
C++
Raw Blame History

/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#include "kernel/yosys.h"
#include "kernel/sigtools.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
struct ShregmapTech
{
virtual ~ShregmapTech() { }
virtual void init(const Module * /*module*/, const SigMap &/*sigmap*/) {}
virtual void non_chain_user(const SigBit &/*bit*/, const Cell* /*cell*/, IdString /*port*/) {}
virtual bool analyze(vector<int> &taps, const vector<SigBit> &qbits) = 0;
virtual bool fixup(Cell *cell, dict<int, SigBit> &taps) = 0;
};
struct ShregmapOptions
{
int minlen, maxlen;
int keep_before, keep_after;
bool zinit, init, params, ffe;
dict<IdString, pair<IdString, IdString>> ffcells;
ShregmapTech *tech;
ShregmapOptions()
{
minlen = 2;
maxlen = 0;
keep_before = 0;
keep_after = 0;
zinit = false;
init = false;
params = false;
ffe = false;
tech = nullptr;
}
};
struct ShregmapTechGreenpak4 : ShregmapTech
{
bool analyze(vector<int> &taps, const vector<SigBit> &/*qbits*/)
{
if (GetSize(taps) > 2 && taps[0] == 0 && taps[2] < 17) {
taps.clear();
return true;
}
if (GetSize(taps) > 2)
return false;
if (taps.back() > 16) return false;
return true;
}
bool fixup(Cell *cell, dict<int, SigBit> &taps)
{
auto D = cell->getPort("\\D");
auto C = cell->getPort("\\C");
auto newcell = cell->module->addCell(NEW_ID, "\\GP_SHREG");
newcell->setPort("\\nRST", State::S1);
newcell->setPort("\\CLK", C);
newcell->setPort("\\IN", D);
int i = 0;
for (auto tap : taps) {
newcell->setPort(i ? "\\OUTB" : "\\OUTA", tap.second);
newcell->setParam(i ? "\\OUTB_TAP" : "\\OUTA_TAP", tap.first + 1);
i++;
}
cell->setParam("\\OUTA_INVERT", 0);
return false;
}
};
struct ShregmapTechXilinx7 : ShregmapTech
{
dict<SigBit, std::tuple<Cell*,int,int>> sigbit_to_shiftx_offset;
const ShregmapOptions &opts;
ShregmapTechXilinx7(const ShregmapOptions &opts) : opts(opts) {}
virtual void init(const Module* module, const SigMap &sigmap) override
{
for (const auto &i : module->cells_) {
auto cell = i.second;
if (cell->type == "$shiftx") {
if (cell->getParam("\\Y_WIDTH") != 1) continue;
int j = 0;
for (auto bit : sigmap(cell->getPort("\\A")))
sigbit_to_shiftx_offset[bit] = std::make_tuple(cell, j++, 0);
log_assert(j == cell->getParam("\\A_WIDTH").as_int());
}
else if (cell->type == "$mux") {
int j = 0;
for (auto bit : sigmap(cell->getPort("\\A")))
sigbit_to_shiftx_offset[bit] = std::make_tuple(cell, 0, j++);
j = 0;
for (auto bit : sigmap(cell->getPort("\\B")))
sigbit_to_shiftx_offset[bit] = std::make_tuple(cell, 1, j++);
}
}
}
virtual void non_chain_user(const SigBit &bit, const Cell *cell, IdString port) override
{
auto it = sigbit_to_shiftx_offset.find(bit);
if (it == sigbit_to_shiftx_offset.end())
return;
if (cell) {
if (cell->type == "$shiftx" && port == "\\A")
return;
if (cell->type == "$mux" && (port == "\\A" || port == "\\B"))
return;
}
sigbit_to_shiftx_offset.erase(it);
}
virtual bool analyze(vector<int> &taps, const vector<SigBit> &qbits) override
{
if (GetSize(taps) == 1)
return taps[0] >= opts.minlen-1 && sigbit_to_shiftx_offset.count(qbits[0]);
if (taps.back() < opts.minlen-1)
return false;
Cell *shiftx = nullptr;
int group = 0;
for (int i = 0; i < GetSize(taps); ++i) {
auto it = sigbit_to_shiftx_offset.find(qbits[i]);
if (it == sigbit_to_shiftx_offset.end())
return false;
// Check taps are sequential
if (i != taps[i])
return false;
// Check taps are not connected to a shift register,
// or sequential to the same shift register
if (i == 0) {
int offset;
std::tie(shiftx,offset,group) = it->second;
if (offset != i)
return false;
}
else {
Cell *shiftx_ = std::get<0>(it->second);
if (shiftx_ != shiftx)
return false;
int offset = std::get<1>(it->second);
if (offset != i)
return false;
int group_ = std::get<2>(it->second);
if (group_ != group)
return false;
}
}
log_assert(shiftx);
// Only map if $shiftx exclusively covers the shift register
if (shiftx->type == "$shiftx") {
if (GetSize(taps) > shiftx->getParam("\\A_WIDTH").as_int())
return false;
// Due to padding the most significant bits of A may be 1'bx,
// and if so, discount them
if (GetSize(taps) < shiftx->getParam("\\A_WIDTH").as_int()) {
const SigSpec A = shiftx->getPort("\\A");
const int A_width = shiftx->getParam("\\A_WIDTH").as_int();
for (int i = GetSize(taps); i < A_width; ++i)
if (A[i] != RTLIL::Sx) return false;
}
else if (GetSize(taps) != shiftx->getParam("\\A_WIDTH").as_int())
return false;
}
else if (shiftx->type == "$mux") {
if (GetSize(taps) != 2)
return false;
}
else log_abort();
return true;
}
virtual bool fixup(Cell *cell, dict<int, SigBit> &taps) override
{
const auto &tap = *taps.begin();
auto bit = tap.second;
auto it = sigbit_to_shiftx_offset.find(bit);
log_assert(it != sigbit_to_shiftx_offset.end());
auto newcell = cell->module->addCell(NEW_ID, "$__XILINX_SHREG_");
newcell->set_src_attribute(cell->get_src_attribute());
newcell->setParam("\\DEPTH", cell->getParam("\\DEPTH"));
newcell->setParam("\\INIT", cell->getParam("\\INIT"));
newcell->setParam("\\CLKPOL", cell->getParam("\\CLKPOL"));
newcell->setParam("\\ENPOL", cell->getParam("\\ENPOL"));
newcell->setPort("\\C", cell->getPort("\\C"));
newcell->setPort("\\D", cell->getPort("\\D"));
if (cell->hasPort("\\E"))
newcell->setPort("\\E", cell->getPort("\\E"));
Cell* shiftx = std::get<0>(it->second);
RTLIL::SigSpec l_wire, q_wire;
if (shiftx->type == "$shiftx") {
l_wire = shiftx->getPort("\\B");
q_wire = shiftx->getPort("\\Y");
shiftx->setPort("\\Y", cell->module->addWire(NEW_ID));
}
else if (shiftx->type == "$mux") {
l_wire = shiftx->getPort("\\S");
q_wire = shiftx->getPort("\\Y");
shiftx->setPort("\\Y", cell->module->addWire(NEW_ID));
}
else log_abort();
newcell->setPort("\\Q", q_wire);
newcell->setPort("\\L", l_wire);
return false;
}
};
struct ShregmapWorker
{
Module *module;
SigMap sigmap;
const ShregmapOptions &opts;
int dff_count, shreg_count;
pool<Cell*> remove_cells;
pool<SigBit> remove_init;
dict<SigBit, bool> sigbit_init;
dict<SigBit, Cell*> sigbit_chain_next;
dict<SigBit, Cell*> sigbit_chain_prev;
pool<SigBit> sigbit_with_non_chain_users;
pool<Cell*> chain_start_cells;
void make_sigbit_chain_next_prev()
{
for (auto wire : module->wires())
{
if (wire->port_output || wire->get_bool_attribute("\\keep")) {
for (auto bit : sigmap(wire)) {
sigbit_with_non_chain_users.insert(bit);
if (opts.tech) opts.tech->non_chain_user(bit, nullptr, {});
}
}
if (wire->attributes.count("\\init")) {
SigSpec initsig = sigmap(wire);
Const initval = wire->attributes.at("\\init");
for (int i = 0; i < GetSize(initsig) && i < GetSize(initval); i++)
if (initval[i] == State::S0 && !opts.zinit)
sigbit_init[initsig[i]] = false;
else if (initval[i] == State::S1)
sigbit_init[initsig[i]] = true;
}
}
for (auto cell : module->cells())
{
if (opts.ffcells.count(cell->type) && !cell->get_bool_attribute("\\keep"))
{
IdString d_port = opts.ffcells.at(cell->type).first;
IdString q_port = opts.ffcells.at(cell->type).second;
SigBit d_bit = sigmap(cell->getPort(d_port).as_bit());
SigBit q_bit = sigmap(cell->getPort(q_port).as_bit());
if (opts.init || sigbit_init.count(q_bit) == 0)
{
if (sigbit_chain_next.count(d_bit)) {
sigbit_with_non_chain_users.insert(d_bit);
} else
sigbit_chain_next[d_bit] = cell;
sigbit_chain_prev[q_bit] = cell;
continue;
}
}
for (auto conn : cell->connections())
if (cell->input(conn.first))
for (auto bit : sigmap(conn.second)) {
sigbit_with_non_chain_users.insert(bit);
if (opts.tech) opts.tech->non_chain_user(bit, cell, conn.first);
}
}
}
void find_chain_start_cells()
{
for (auto it : sigbit_chain_next)
{
if (opts.tech == nullptr && sigbit_with_non_chain_users.count(it.first))
goto start_cell;
if (sigbit_chain_prev.count(it.first) != 0)
{
Cell *c1 = sigbit_chain_prev.at(it.first);
Cell *c2 = it.second;
if (c1->type != c2->type)
goto start_cell;
if (c1->parameters != c2->parameters)
goto start_cell;
IdString d_port = opts.ffcells.at(c1->type).first;
IdString q_port = opts.ffcells.at(c1->type).second;
auto c1_conn = c1->connections();
auto c2_conn = c1->connections();
c1_conn.erase(d_port);
c1_conn.erase(q_port);
c2_conn.erase(d_port);
c2_conn.erase(q_port);
if (c1_conn != c2_conn)
goto start_cell;
continue;
}
start_cell:
chain_start_cells.insert(it.second);
}
}
vector<Cell*> create_chain(Cell *start_cell)
{
vector<Cell*> chain;
Cell *c = start_cell;
while (c != nullptr)
{
chain.push_back(c);
IdString q_port = opts.ffcells.at(c->type).second;
SigBit q_bit = sigmap(c->getPort(q_port).as_bit());
if (sigbit_chain_next.count(q_bit) == 0)
break;
c = sigbit_chain_next.at(q_bit);
if (chain_start_cells.count(c) != 0)
break;
}
return chain;
}
void process_chain(vector<Cell*> &chain)
{
if (GetSize(chain) < opts.keep_before + opts.minlen + opts.keep_after)
return;
int cursor = opts.keep_before;
while (cursor < GetSize(chain) - opts.keep_after)
{
int depth = GetSize(chain) - opts.keep_after - cursor;
if (opts.maxlen > 0)
depth = std::min(opts.maxlen, depth);
Cell *first_cell = chain[cursor];
IdString q_port = opts.ffcells.at(first_cell->type).second;
dict<int, SigBit> taps_dict;
if (opts.tech)
{
vector<SigBit> qbits;
vector<int> taps;
for (int i = 0; i < depth; i++)
{
Cell *cell = chain[cursor+i];
auto qbit = sigmap(cell->getPort(q_port));
qbits.push_back(qbit);
if (sigbit_with_non_chain_users.count(qbit))
taps.push_back(i);
}
while (depth > 0)
{
if (taps.empty() || taps.back() < depth-1)
taps.push_back(depth-1);
if (opts.tech->analyze(taps, qbits))
break;
taps.pop_back();
depth--;
}
depth = 0;
for (auto tap : taps) {
taps_dict[tap] = qbits.at(tap);
log_assert(depth < tap+1);
depth = tap+1;
}
}
if (depth < 2) {
cursor++;
continue;
}
Cell *last_cell = chain[cursor+depth-1];
log("Converting %s.%s ... %s.%s to a shift register with depth %d.\n",
log_id(module), log_id(first_cell), log_id(module), log_id(last_cell), depth);
dff_count += depth;
shreg_count += 1;
string shreg_cell_type_str = "$__SHREG";
if (opts.params) {
shreg_cell_type_str += "_";
} else {
if (first_cell->type[1] != '_')
shreg_cell_type_str += "_";
shreg_cell_type_str += first_cell->type.substr(1);
}
if (opts.init) {
vector<State> initval;
for (int i = depth-1; i >= 0; i--) {
SigBit bit = sigmap(chain[cursor+i]->getPort(q_port).as_bit());
if (sigbit_init.count(bit) == 0)
initval.push_back(State::Sx);
else if (sigbit_init.at(bit))
initval.push_back(State::S1);
else
initval.push_back(State::S0);
remove_init.insert(bit);
}
first_cell->setParam("\\INIT", initval);
}
if (opts.zinit)
for (int i = depth-1; i >= 0; i--) {
SigBit bit = sigmap(chain[cursor+i]->getPort(q_port).as_bit());
remove_init.insert(bit);
}
if (opts.params)
{
int param_clkpol = -1;
int param_enpol = 2;
if (first_cell->type == "$_DFF_N_") param_clkpol = 0;
if (first_cell->type == "$_DFF_P_") param_clkpol = 1;
if (first_cell->type == "$_DFFE_NN_") param_clkpol = 0, param_enpol = 0;
if (first_cell->type == "$_DFFE_NP_") param_clkpol = 0, param_enpol = 1;
if (first_cell->type == "$_DFFE_PN_") param_clkpol = 1, param_enpol = 0;
if (first_cell->type == "$_DFFE_PP_") param_clkpol = 1, param_enpol = 1;
log_assert(param_clkpol >= 0);
first_cell->setParam("\\CLKPOL", param_clkpol);
if (opts.ffe) first_cell->setParam("\\ENPOL", param_enpol);
}
first_cell->type = shreg_cell_type_str;
first_cell->setPort(q_port, last_cell->getPort(q_port));
first_cell->setParam("\\DEPTH", depth);
if (opts.tech != nullptr && !opts.tech->fixup(first_cell, taps_dict))
remove_cells.insert(first_cell);
for (int i = 1; i < depth; i++)
remove_cells.insert(chain[cursor+i]);
cursor += depth;
}
}
void cleanup()
{
for (auto cell : remove_cells)
module->remove(cell);
for (auto wire : module->wires())
{
if (wire->attributes.count("\\init") == 0)
continue;
SigSpec initsig = sigmap(wire);
Const &initval = wire->attributes.at("\\init");
for (int i = 0; i < GetSize(initsig) && i < GetSize(initval); i++)
if (remove_init.count(initsig[i]))
initval[i] = State::Sx;
if (SigSpec(initval).is_fully_undef())
wire->attributes.erase("\\init");
}
remove_cells.clear();
sigbit_chain_next.clear();
sigbit_chain_prev.clear();
chain_start_cells.clear();
}
ShregmapWorker(Module *module, const ShregmapOptions &opts) :
module(module), sigmap(module), opts(opts), dff_count(0), shreg_count(0)
{
if (opts.tech)
opts.tech->init(module, sigmap);
make_sigbit_chain_next_prev();
find_chain_start_cells();
for (auto c : chain_start_cells) {
vector<Cell*> chain = create_chain(c);
process_chain(chain);
}
cleanup();
}
};
struct ShregmapPass : public Pass {
ShregmapPass() : Pass("shregmap", "map shift registers") { }
void help() YS_OVERRIDE
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" shregmap [options] [selection]\n");
log("\n");
log("This pass converts chains of $_DFF_[NP]_ gates to target specific shift register\n");
log("primitives. The generated shift register will be of type $__SHREG_DFF_[NP]_ and\n");
log("will use the same interface as the original $_DFF_*_ cells. The cell parameter\n");
log("'DEPTH' will contain the depth of the shift register. Use a target-specific\n");
log("'techmap' map file to convert those cells to the actual target cells.\n");
log("\n");
log(" -minlen N\n");
log(" minimum length of shift register (default = 2)\n");
log(" (this is the length after -keep_before and -keep_after)\n");
log("\n");
log(" -maxlen N\n");
log(" maximum length of shift register (default = no limit)\n");
log(" larger chains will be mapped to multiple shift register instances\n");
log("\n");
log(" -keep_before N\n");
log(" number of DFFs to keep before the shift register (default = 0)\n");
log("\n");
log(" -keep_after N\n");
log(" number of DFFs to keep after the shift register (default = 0)\n");
log("\n");
log(" -clkpol pos|neg|any\n");
log(" limit match to only positive or negative edge clocks. (default = any)\n");
log("\n");
log(" -enpol pos|neg|none|any_or_none|any\n");
log(" limit match to FFs with the specified enable polarity. (default = none)\n");
log("\n");
log(" -match <cell_type>[:<d_port_name>:<q_port_name>]\n");
log(" match the specified cells instead of $_DFF_N_ and $_DFF_P_. If\n");
log(" ':<d_port_name>:<q_port_name>' is omitted then 'D' and 'Q' is used\n");
log(" by default. E.g. the option '-clkpol pos' is just an alias for\n");
log(" '-match $_DFF_P_', which is an alias for '-match $_DFF_P_:D:Q'.\n");
log("\n");
log(" -params\n");
log(" instead of encoding the clock and enable polarity in the cell name by\n");
log(" deriving from the original cell name, simply name all generated cells\n");
log(" $__SHREG_ and use CLKPOL and ENPOL parameters. An ENPOL value of 2 is\n");
log(" used to denote cells without enable input. The ENPOL parameter is\n");
log(" omitted when '-enpol none' (or no -enpol option) is passed.\n");
log("\n");
log(" -zinit\n");
log(" assume the shift register is automatically zero-initialized, so it\n");
log(" becomes legal to merge zero initialized FFs into the shift register.\n");
log("\n");
log(" -init\n");
log(" map initialized registers to the shift reg, add an INIT parameter to\n");
log(" generated cells with the initialization value. (first bit to shift out\n");
log(" in LSB position)\n");
log("\n");
log(" -tech greenpak4\n");
log(" map to greenpak4 shift registers.\n");
log(" this option also implies -clkpol pos -zinit\n");
log("\n");
log(" -tech xilinx\n");
log(" map to xilinx dynamic-length shift registers.\n");
log(" this option also implies -params -init\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
{
ShregmapOptions opts;
string clkpol, enpol;
log_header(design, "Executing SHREGMAP pass (map shift registers).\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++)
{
if (args[argidx] == "-clkpol" && argidx+1 < args.size()) {
clkpol = args[++argidx];
continue;
}
if (args[argidx] == "-enpol" && argidx+1 < args.size()) {
enpol = args[++argidx];
continue;
}
if (args[argidx] == "-match" && argidx+1 < args.size()) {
vector<string> match_args = split_tokens(args[++argidx], ":");
if (GetSize(match_args) < 2)
match_args.push_back("D");
if (GetSize(match_args) < 3)
match_args.push_back("Q");
IdString id_cell_type(RTLIL::escape_id(match_args[0]));
IdString id_d_port_name(RTLIL::escape_id(match_args[1]));
IdString id_q_port_name(RTLIL::escape_id(match_args[2]));
opts.ffcells[id_cell_type] = make_pair(id_d_port_name, id_q_port_name);
continue;
}
if (args[argidx] == "-minlen" && argidx+1 < args.size()) {
opts.minlen = atoi(args[++argidx].c_str());
continue;
}
if (args[argidx] == "-maxlen" && argidx+1 < args.size()) {
opts.maxlen = atoi(args[++argidx].c_str());
continue;
}
if (args[argidx] == "-keep_before" && argidx+1 < args.size()) {
opts.keep_before = atoi(args[++argidx].c_str());
continue;
}
if (args[argidx] == "-keep_after" && argidx+1 < args.size()) {
opts.keep_after = atoi(args[++argidx].c_str());
continue;
}
if (args[argidx] == "-tech" && argidx+1 < args.size() && opts.tech == nullptr) {
string tech = args[++argidx];
if (tech == "greenpak4") {
clkpol = "pos";
opts.zinit = true;
opts.tech = new ShregmapTechGreenpak4;
}
else if (tech == "xilinx") {
opts.init = true;
opts.params = true;
enpol = "any_or_none";
opts.tech = new ShregmapTechXilinx7(opts);
} else {
argidx--;
break;
}
continue;
}
if (args[argidx] == "-zinit") {
opts.zinit = true;
continue;
}
if (args[argidx] == "-init") {
opts.init = true;
continue;
}
if (args[argidx] == "-params") {
opts.params = true;
continue;
}
break;
}
extra_args(args, argidx, design);
if (opts.zinit && opts.init)
log_cmd_error("Options -zinit and -init are exclusive!\n");
if (opts.ffcells.empty())
{
bool clk_pos = clkpol == "" || clkpol == "pos" || clkpol == "any";
bool clk_neg = clkpol == "" || clkpol == "neg" || clkpol == "any";
bool en_none = enpol == "" || enpol == "none" || enpol == "any_or_none";
bool en_pos = enpol == "pos" || enpol == "any" || enpol == "any_or_none";
bool en_neg = enpol == "neg" || enpol == "any" || enpol == "any_or_none";
if (clk_pos && en_none)
opts.ffcells["$_DFF_P_"] = make_pair(IdString("\\D"), IdString("\\Q"));
if (clk_neg && en_none)
opts.ffcells["$_DFF_N_"] = make_pair(IdString("\\D"), IdString("\\Q"));
if (clk_pos && en_pos)
opts.ffcells["$_DFFE_PP_"] = make_pair(IdString("\\D"), IdString("\\Q"));
if (clk_pos && en_neg)
opts.ffcells["$_DFFE_PN_"] = make_pair(IdString("\\D"), IdString("\\Q"));
if (clk_neg && en_pos)
opts.ffcells["$_DFFE_NP_"] = make_pair(IdString("\\D"), IdString("\\Q"));
if (clk_neg && en_neg)
opts.ffcells["$_DFFE_NN_"] = make_pair(IdString("\\D"), IdString("\\Q"));
if (en_pos || en_neg)
opts.ffe = true;
}
else
{
if (!clkpol.empty())
log_cmd_error("Options -clkpol and -match are exclusive!\n");
if (!enpol.empty())
log_cmd_error("Options -enpol and -match are exclusive!\n");
if (opts.params)
log_cmd_error("Options -params and -match are exclusive!\n");
}
int dff_count = 0;
int shreg_count = 0;
for (auto module : design->selected_modules()) {
ShregmapWorker worker(module, opts);
dff_count += worker.dff_count;
shreg_count += worker.shreg_count;
}
log("Converted %d dff cells into %d shift registers.\n", dff_count, shreg_count);
if (opts.tech != nullptr) {
delete opts.tech;
opts.tech = nullptr;
}
}
} ShregmapPass;
PRIVATE_NAMESPACE_END
Reference in New Issue View Git Blame Copy Permalink