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Add clock buffer insertion pass, improve iopadmap.

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A few new attributes are defined for use in cell libraries:

- iopad_external_pin: marks PAD cell's external-facing pin.  Pad
  insertion will be skipped for ports that are already connected
  to such a pin.
- clkbuf_sink: marks an input pin as a clock pin, requesting clock
  buffer insertion.
- clkbuf_driver: marks an output pin as a clock buffer output pin.
  Clock buffer insertion will be skipped for nets that are already
  driven by such a pin.

All three are module attributes that should be set to a comma-separeted
list of pin names.

Clock buffer insertion itself works as follows:

1. All cell ports, starting from bottom up, can be marked as clock sinks
   (requesting clock buffer insertion) or as clock buffer outputs.
2. If a wire in a given module is driven by a cell port that is a clock
   buffer output, it is in turn also considered a clock buffer output.
3. If an input port in a non-top module is connected to a clock sink in a
   contained cell, it is also in turn considered a clock sink.
4. If a wire in a module is driven by a non-clock-buffer cell, and is
   also connected to a clock sink port in a contained cell, a clock
   buffer is inserted in this module.
5. For the top module, a clock buffer is also inserted on input ports
   connected to clock sinks, optionally with a special kind of input
   PAD (such as IBUFG for Xilinx).
6. Clock buffer insertion on a given wire is skipped if the clkbuf_inhibit
   attribute is set on it.
This commit is contained in:
Marcin Kościelnicki 2019-08-12 15:57:43 +00:00
parent 78b30bbb11
commit f4c62f33ac
10 changed files with 577 additions and 93 deletions
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76
passes/techmap/iopadmap.cc
View file

@ -32,6 +32,19 @@ void split_portname_pair(std::string &port1, std::string &port2)
}
}
std::vector<std::string> split(std::string text, const char *delim)
{
std::vector<std::string> list;
char *p = strdup(text.c_str());
char *t = strtok(p, delim);
while (t != NULL) {
list.push_back(t);
t = strtok(NULL, delim);
}
free(p);
return list;
}
struct IopadmapPass : public Pass {
IopadmapPass() : Pass("iopadmap", "technology mapping of i/o pads (or buffers)") { }
void help() YS_OVERRIDE
@ -64,6 +77,11 @@ struct IopadmapPass : public Pass {
log(" of the tristate driver and the 2nd portname is the internal output\n");
log(" buffering the external signal.\n");
log("\n");
log(" -ignore <celltype> <portname>[:<portname>]*\n");
log(" Skips mapping inputs/outputs that are already connected to given\n");
log(" ports of the given cell. Can be used multiple times. This is in\n");
log(" addition to the cells specified as mapping targets.\n");
log("\n");
log(" -widthparam <param_name>\n");
log(" Use the specified parameter name to set the port width.\n");
log("\n");
@ -88,6 +106,7 @@ struct IopadmapPass : public Pass {
std::string toutpad_celltype, toutpad_portname, toutpad_portname2, toutpad_portname3;
std::string tinoutpad_celltype, tinoutpad_portname, tinoutpad_portname2, tinoutpad_portname3, tinoutpad_portname4;
std::string widthparam, nameparam;
pool<pair<IdString, IdString>> ignore;
bool flag_bits = false;
size_t argidx;
@ -127,6 +146,18 @@ struct IopadmapPass : public Pass {
split_portname_pair(tinoutpad_portname3, tinoutpad_portname4);
continue;
}
if (arg == "-ignore" && argidx+2 < args.size()) {
std::string ignore_celltype = args[++argidx];
std::string ignore_portname = args[++argidx];
std::string ignore_portname2;
while (!ignore_portname.empty()) {
split_portname_pair(ignore_portname, ignore_portname2);
ignore.insert(make_pair(RTLIL::escape_id(ignore_celltype), RTLIL::escape_id(ignore_portname)));
ignore_portname = ignore_portname2;
}
continue;
}
if (arg == "-widthparam" && argidx+1 < args.size()) {
widthparam = args[++argidx];
continue;
@ -143,6 +174,28 @@ struct IopadmapPass : public Pass {
}
extra_args(args, argidx, design);
if (!inpad_portname2.empty())
ignore.insert(make_pair(RTLIL::escape_id(inpad_celltype), RTLIL::escape_id(inpad_portname2)));
if (!outpad_portname2.empty())
ignore.insert(make_pair(RTLIL::escape_id(outpad_celltype), RTLIL::escape_id(outpad_portname2)));
if (!inoutpad_portname2.empty())
ignore.insert(make_pair(RTLIL::escape_id(inoutpad_celltype), RTLIL::escape_id(inoutpad_portname2)));
if (!toutpad_portname3.empty())
ignore.insert(make_pair(RTLIL::escape_id(toutpad_celltype), RTLIL::escape_id(toutpad_portname3)));
if (!tinoutpad_portname4.empty())
ignore.insert(make_pair(RTLIL::escape_id(tinoutpad_celltype), RTLIL::escape_id(tinoutpad_portname4)));
for (auto module : design->modules())
{
auto it = module->attributes.find("\\iopad_external_pin");
if (it != module->attributes.end()) {
auto value = it->second.decode_string();
for (auto name : split(value, ",")) {
ignore.insert(make_pair(module->name, RTLIL::escape_id(name)));
}
}
}
for (auto module : design->selected_modules())
{
dict<IdString, pool<int>> skip_wires;
@ -150,28 +203,11 @@ struct IopadmapPass : public Pass {
SigMap sigmap(module);
for (auto cell : module->cells())
{
if (cell->type == RTLIL::escape_id(inpad_celltype) && cell->hasPort(RTLIL::escape_id(inpad_portname2)))
for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(inpad_portname2))))
for (auto port : cell->connections())
if (ignore.count(make_pair(cell->type, port.first)))
for (auto bit : sigmap(port.second))
skip_wire_bits.insert(bit);
if (cell->type == RTLIL::escape_id(outpad_celltype) && cell->hasPort(RTLIL::escape_id(outpad_portname2)))
for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(outpad_portname2))))
skip_wire_bits.insert(bit);
if (cell->type == RTLIL::escape_id(inoutpad_celltype) && cell->hasPort(RTLIL::escape_id(inoutpad_portname2)))
for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(inoutpad_portname2))))
skip_wire_bits.insert(bit);
if (cell->type == RTLIL::escape_id(toutpad_celltype) && cell->hasPort(RTLIL::escape_id(toutpad_portname3)))
for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(toutpad_portname3))))
skip_wire_bits.insert(bit);
if (cell->type == RTLIL::escape_id(tinoutpad_celltype) && cell->hasPort(RTLIL::escape_id(tinoutpad_portname4)))
for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(tinoutpad_portname4))))
skip_wire_bits.insert(bit);
}
if (!toutpad_celltype.empty() || !tinoutpad_celltype.empty())
{
dict<SigBit, pair<IdString, pool<IdString>>> tbuf_bits;