nextpnr/gowin/globals.h
YRabbit b8ab3116b2 gowin: improve clock wire routing
The dedicated router for clock wires now understands not only the IO
pins but also the rPLL outputs as clock sources.

This simple router sets an optimal route, so it is now the default
router. It can be disabled with the --disable-globals command line flag
if desired, but this is not recommended due to possible clock skew.

Still for GW1N-4C there is no good router for clock wires as there
external quartz resonator is connected via PLL.

Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
2022-12-30 11:55:39 +10:00

92 lines
2.7 KiB
C++

/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 gatecat <gatecat@ds0.me>
* Copyright (C) 2022 YRabbit <rabbit@yrabbit.cyou>
*
* 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.
*
*/
#ifndef GOWIN_GLOBALS_H
#define GOWIN_GLOBALS_H
#include "nextpnr.h"
NEXTPNR_NAMESPACE_BEGIN
class GowinGlobalRouter
{
public:
GowinGlobalRouter() {}
private:
// wire -> clock#
dict<WireId, int> used_wires;
// ordered nets
struct globalnet_t
{
IdString name;
int clock_ports;
BelId clock_bel;
WireId clock_wire; // clock wire if there is one
int clock; // clock #
globalnet_t()
{
name = IdString();
clock_ports = 0;
clock_bel = BelId();
clock_wire = WireId();
clock = -1;
}
globalnet_t(IdString _name)
{
name = _name;
clock_ports = 0;
clock_bel = BelId();
clock_wire = WireId();
clock = -1;
}
// sort
bool operator<(const globalnet_t &other) const
{
if ((clock_wire != WireId()) ^ (other.clock_wire != WireId())) {
return !(clock_wire != WireId());
}
return clock_ports < other.clock_ports;
}
// search
bool operator==(const globalnet_t &other) const { return name == other.name; }
};
// discovered nets
std::vector<globalnet_t> nets;
bool is_clock_port(PortRef const &user);
std::pair<WireId, BelId> clock_src(Context *ctx, PortRef const &driver);
void gather_clock_nets(Context *ctx, std::vector<globalnet_t> &clock_nets);
IdString route_to_non_clock_port(Context *ctx, WireId const dstWire, int clock, pool<IdString> &used_pips,
pool<IdString> &undo_wires);
void route_net(Context *ctx, globalnet_t const &net);
public:
void mark_globals(Context *ctx);
void route_globals(Context *ctx);
};
NEXTPNR_NAMESPACE_END
#endif // GOWIN_GLOBALS_H