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/*
* 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/log.h"
#include "kernel/register.h"
#include "kernel/sigtools.h"
#include "kernel/consteval.h"
#include "kernel/celltypes.h"
#include "fsmdata.h"
static RTLIL::Module *module;
static SigMap assign_map;
typedef std::pair<RTLIL::Cell*, RTLIL::IdString> sig2driver_entry_t;
static SigSet<sig2driver_entry_t> sig2driver, sig2user;
static std::set<RTLIL::Cell*> muxtree_cells;
static SigPool sig_at_port;
static bool check_state_mux_tree(RTLIL::SigSpec old_sig, RTLIL::SigSpec sig, SigPool &recursion_monitor)
{
if (sig_at_port.check_any(assign_map(sig)))
return false;
if (sig.is_fully_const() || old_sig == sig)
return true;
if (recursion_monitor.check_any(sig)) {
log("Warning: logic loop in mux tree at signal %s in module %s.\n",
log_signal(sig), RTLIL::id2cstr(module->name));
return false;
}
recursion_monitor.add(sig);
std::set<sig2driver_entry_t> cellport_list;
sig2driver.find(sig, cellport_list);
for (auto &cellport : cellport_list) {
if ((cellport.first->type != "$mux" && cellport.first->type != "$pmux") || cellport.second != "\\Y")
return false;
RTLIL::SigSpec sig_a = assign_map(cellport.first->getPort("\\A"));
RTLIL::SigSpec sig_b = assign_map(cellport.first->getPort("\\B"));
if (!check_state_mux_tree(old_sig, sig_a, recursion_monitor))
return false;
for (int i = 0; i < sig_b.size(); i += sig_a.size())
if (!check_state_mux_tree(old_sig, sig_b.extract(i, sig_a.size()), recursion_monitor))
return false;
muxtree_cells.insert(cellport.first);
}
recursion_monitor.del(sig);
return true;
}
static bool check_state_users(RTLIL::SigSpec sig)
{
if (sig_at_port.check_any(assign_map(sig)))
return false;
std::set<sig2driver_entry_t> cellport_list;
sig2user.find(sig, cellport_list);
for (auto &cellport : cellport_list) {
RTLIL::Cell *cell = cellport.first;
if (muxtree_cells.count(cell) > 0)
continue;
if (cellport.second != "\\A" && cellport.second != "\\B")
return false;
if (!cell->hasPort("\\A") || !cell->hasPort("\\B") || !cell->hasPort("\\Y"))
return false;
for (auto &port_it : cell->connections())
if (port_it.first != "\\A" && port_it.first != "\\B" && port_it.first != "\\Y")
return false;
if (assign_map(cell->getPort("\\A")) == sig && cell->getPort("\\B").is_fully_const())
continue;
if (assign_map(cell->getPort("\\B")) == sig && cell->getPort("\\A").is_fully_const())
continue;
return false;
}
return true;
}
static void detect_fsm(RTLIL::Wire *wire)
{
if (wire->attributes.count("\\fsm_encoding") > 0 || wire->width <= 1)
return;
if (sig_at_port.check_any(assign_map(RTLIL::SigSpec(wire))))
return;
std::set<sig2driver_entry_t> cellport_list;
sig2driver.find(RTLIL::SigSpec(wire), cellport_list);
for (auto &cellport : cellport_list) {
if ((cellport.first->type != "$dff" && cellport.first->type != "$adff") || cellport.second != "\\Q")
continue;
muxtree_cells.clear();
SigPool recursion_monitor;
RTLIL::SigSpec sig_q = assign_map(cellport.first->getPort("\\Q"));
RTLIL::SigSpec sig_d = assign_map(cellport.first->getPort("\\D"));
if (sig_q == RTLIL::SigSpec(wire) && check_state_mux_tree(sig_q, sig_d, recursion_monitor) && check_state_users(sig_q)) {
log("Found FSM state register %s in module %s.\n", wire->name.c_str(), module->name.c_str());
wire->attributes["\\fsm_encoding"] = RTLIL::Const("auto");
return;
}
}
}
struct FsmDetectPass : public Pass {
FsmDetectPass() : Pass("fsm_detect", "finding FSMs in design") { }
virtual void help()
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" fsm_detect [selection]\n");
log("\n");
log("This pass detects finite state machines by identifying the state signal.\n");
log("The state signal is then marked by setting the attribute 'fsm_encoding'\n");
log("on the state signal to \"auto\".\n");
log("\n");
log("Existing 'fsm_encoding' attributes are not changed by this pass.\n");
log("\n");
log("Signals can be protected from being detected by this pass by setting the\n");
log("'fsm_encoding' attribute to \"none\".\n");
log("\n");
}
virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
{
log_header("Executing FSM_DETECT pass (finding FSMs in design).\n");
extra_args(args, 1, design);
CellTypes ct;
ct.setup_internals();
ct.setup_internals_mem();
ct.setup_stdcells();
ct.setup_stdcells_mem();
for (auto &mod_it : design->modules_)
{
if (!design->selected(mod_it.second))
continue;
module = mod_it.second;
assign_map.set(module);
sig2driver.clear();
sig2user.clear();
sig_at_port.clear();
for (auto &cell_it : module->cells_)
for (auto &conn_it : cell_it.second->connections()) {
if (ct.cell_output(cell_it.second->type, conn_it.first) || !ct.cell_known(cell_it.second->type)) {
RTLIL::SigSpec sig = conn_it.second;
assign_map.apply(sig);
sig2driver.insert(sig, sig2driver_entry_t(cell_it.second, conn_it.first));
}
if (!ct.cell_known(cell_it.second->type) || ct.cell_input(cell_it.second->type, conn_it.first)) {
RTLIL::SigSpec sig = conn_it.second;
assign_map.apply(sig);
sig2user.insert(sig, sig2driver_entry_t(cell_it.second, conn_it.first));
}
}
for (auto &wire_it : module->wires_)
if (wire_it.second->port_id != 0)
sig_at_port.add(assign_map(RTLIL::SigSpec(wire_it.second)));
for (auto &wire_it : module->wires_)
if (design->selected(module, wire_it.second))
detect_fsm(wire_it.second);
}
assign_map.clear();
sig2driver.clear();
sig2user.clear();
muxtree_cells.clear();
}
} FsmDetectPass;
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