nextpnr/himbaechel/uarch/xilinx/pack_io.cc
gatecat 5bfe0dd1b1 himbaechel: Adding a xilinx uarch for xc7 with prjxray
Signed-off-by: gatecat <gatecat@ds0.me>
2023-11-14 17:12:09 +01:00

498 lines
21 KiB
C++

/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2019-23 Myrtle Shah <gatecat@ds0.me>
*
* 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 <algorithm>
#include <boost/algorithm/string.hpp>
#include <queue>
#include <unordered_set>
#include "design_utils.h"
#include "extra_data.h"
#include "log.h"
#include "nextpnr.h"
#include "pack.h"
#include "pins.h"
#define HIMBAECHEL_CONSTIDS "uarch/xilinx/constids.inc"
#include "himbaechel_constids.h"
NEXTPNR_NAMESPACE_BEGIN
CellInfo *XilinxPacker::insert_obuf(IdString name, IdString type, NetInfo *i, NetInfo *o, NetInfo *tri)
{
auto obuf = create_cell(type, name);
obuf->connectPort(id_I, i);
obuf->connectPort(id_T, tri);
obuf->connectPort(id_O, o);
return obuf;
}
CellInfo *XilinxPacker::insert_outinv(IdString name, NetInfo *i, NetInfo *o)
{
auto inv = create_cell(id_INV, name);
inv->connectPort(id_I, i);
inv->connectPort(id_O, o);
return inv;
}
CellInfo *XC7Packer::insert_ibuf(IdString name, IdString type, NetInfo *i, NetInfo *o)
{
auto inbuf = create_cell(type, name);
inbuf->connectPort(id_I, i);
inbuf->connectPort(id_O, o);
return inbuf;
}
CellInfo *XC7Packer::insert_diffibuf(IdString name, IdString type, const std::array<NetInfo *, 2> &i, NetInfo *o)
{
auto inbuf = create_cell(type, name);
inbuf->connectPort(id_I, i[0]);
inbuf->connectPort(id_IB, i[1]);
inbuf->connectPort(id_O, o);
return inbuf;
}
NetInfo *XilinxPacker::invert_net(NetInfo *toinv)
{
if (toinv == nullptr)
return nullptr;
// If net is driven by an inverter, don't double-invert, which could cause problems with timing
// and IOLOGIC packing
if (toinv->driver.cell != nullptr && toinv->driver.cell->type == id_LUT1 &&
int_or_default(toinv->driver.cell->params, id_INIT, 0) == 1) {
NetInfo *preinv = toinv->driver.cell->getPort(id_I0);
// If only one user, also sweep the inversion LUT to avoid packing issues
if (toinv->users.entries() == 1) {
packed_cells.insert(toinv->driver.cell->name);
toinv->driver.cell->disconnectPort(id_I0);
toinv->driver.cell->disconnectPort(id_O);
}
return preinv;
} else {
NetInfo *inv = ctx->createNet(ctx->idf("%s$inverted%d", toinv->name.c_str(ctx), autoidx++));
create_lut(inv->name.str(ctx) + "$lut", {toinv}, inv, Property(1));
return inv;
}
}
std::pair<CellInfo *, PortRef> XilinxPacker::insert_pad_and_buf(CellInfo *npnr_io)
{
// Given a nextpnr IO buffer, create a PAD instance and insert an IO buffer if one isn't already present
std::pair<CellInfo *, PortRef> result;
std::unique_ptr<CellInfo> pad_cell = std::make_unique<CellInfo>(ctx, npnr_io->name, id_PAD);
pad_cell->addInout(id_PAD);
// Copy IO attributes to pad
for (auto &attr : npnr_io->attrs)
pad_cell->attrs[attr.first] = attr.second;
NetInfo *ionet = nullptr;
PortRef iobuf;
iobuf.cell = nullptr;
if (npnr_io->type == ctx->id("$nextpnr_obuf") || npnr_io->type == ctx->id("$nextpnr_iobuf")) {
ionet = npnr_io->getPort(id_I);
if (ionet != nullptr && ionet->driver.cell != nullptr)
if (toplevel_ports.count(ionet->driver.cell->type) &&
toplevel_ports.at(ionet->driver.cell->type).count(ionet->driver.port)) {
if (ionet->users.entries() > 1)
log_error("IO buffer '%s' is connected to more than a single top level IO pin.\n",
ionet->driver.cell->name.c_str(ctx));
iobuf = ionet->driver;
}
pad_cell->attrs[id_X_IO_DIR] = std::string(npnr_io->type == ctx->id("$nextpnr_obuf") ? "OUT" : "INOUT");
}
if (npnr_io->type == ctx->id("$nextpnr_ibuf") || npnr_io->type == ctx->id("$nextpnr_iobuf")) {
ionet = npnr_io->getPort(id_O);
if (ionet != nullptr)
for (auto &usr : ionet->users)
if (toplevel_ports.count(usr.cell->type) && toplevel_ports.at(usr.cell->type).count(usr.port)) {
if (ionet->users.entries() > 1)
log_error("IO buffer '%s' is connected to more than a single top level IO pin.\n",
usr.cell->name.c_str(ctx));
iobuf = usr;
}
pad_cell->attrs[id_X_IO_DIR] = std::string(npnr_io->type == ctx->id("$nextpnr_ibuf") ? "IN" : "INOUT");
}
if (!iobuf.cell) {
// No IO buffer, need to create one
log_error(
" IO port '%s' is missing an IO buffer, do you need to remove -noiopad from your Yosys arguments?\n",
npnr_io->name.c_str(ctx));
} else {
log_info(" IO port '%s' driven by %s '%s'\n", npnr_io->name.c_str(ctx), iobuf.cell->type.c_str(ctx),
iobuf.cell->name.c_str(ctx));
}
NPNR_ASSERT(ionet != nullptr);
for (auto &port : npnr_io->ports)
npnr_io->disconnectPort(port.first);
pad_cell->connectPort(id_PAD, ionet);
if (iobuf.cell->ports.at(iobuf.port).net != ionet) {
iobuf.cell->disconnectPort(iobuf.port);
iobuf.cell->connectPort(iobuf.port, ionet);
}
result.first = pad_cell.get();
result.second = iobuf;
// delete the npnr io and then add the pad, to avoid a name conflict
for (auto &port : npnr_io->ports) {
npnr_io->disconnectPort(port.first);
}
ctx->cells.erase(npnr_io->name);
ctx->cells[result.first->name] = std::move(pad_cell);
return result;
}
void XC7Packer::decompose_iob(CellInfo *xil_iob, bool is_hr, const std::string &iostandard)
{
bool is_se_ibuf = xil_iob->type.in(id_IBUF, id_IBUF_IBUFDISABLE, id_IBUF_INTERMDISABLE);
bool is_se_iobuf = xil_iob->type.in(id_IOBUF, id_IOBUF_DCIEN, id_IOBUF_INTERMDISABLE);
bool is_se_obuf = xil_iob->type.in(id_OBUF, id_OBUFT);
auto pad_site = [&](NetInfo *n) {
for (auto user : n->users)
if (user.cell->type == id_PAD)
return uarch->get_bel_site(ctx->getBelByNameStr(user.cell->attrs[id_BEL].as_string()));
NPNR_ASSERT_FALSE(("can't find PAD for net " + n->name.str(ctx)).c_str());
};
if (is_se_ibuf || is_se_iobuf) {
log_info("Generating input buffer for '%s'\n", xil_iob->name.c_str(ctx));
NetInfo *pad_net = xil_iob->getPort(is_se_iobuf ? id_IO : id_I);
NPNR_ASSERT(pad_net != nullptr);
auto site = pad_site(pad_net);
if (!is_se_iobuf)
xil_iob->disconnectPort(id_I);
NetInfo *top_out = xil_iob->getPort(id_O);
xil_iob->disconnectPort(id_O);
IdString ibuf_type = id_IBUF;
if (xil_iob->type.in(id_IBUF_IBUFDISABLE, id_IOBUF_DCIEN))
ibuf_type = id_IBUF_IBUFDISABLE;
if (xil_iob->type.in(id_IBUF_INTERMDISABLE, id_IOBUF_INTERMDISABLE))
ibuf_type = id_IBUF_INTERMDISABLE;
CellInfo *inbuf = insert_ibuf(int_name(xil_iob->name, "IBUF", is_se_iobuf), ibuf_type, pad_net, top_out);
std::string tile = ctx->get_tile_type(site.tile).str(ctx);
if (boost::starts_with(tile, "RIOB18"))
ctx->bindBel(uarch->get_site_bel(site, ctx->id("IOB18.INBUF_DCIEN")), inbuf, STRENGTH_LOCKED);
else
ctx->bindBel(uarch->get_site_bel(site, ctx->id("IOB33.INBUF_EN")), inbuf, STRENGTH_LOCKED);
xil_iob->movePortTo(id_IBUFDISABLE, inbuf, id_IBUFDISABLE);
xil_iob->movePortTo(id_INTERMDISABLE, inbuf, id_INTERMDISABLE);
}
if (is_se_obuf || is_se_iobuf) {
log_info("Generating output buffer for '%s'\n", xil_iob->name.c_str(ctx));
NetInfo *pad_net = xil_iob->getPort(is_se_iobuf ? id_IO : id_O);
NPNR_ASSERT(pad_net != nullptr);
auto site = pad_site(pad_net);
xil_iob->disconnectPort(is_se_iobuf ? id_IO : id_O);
bool has_dci = xil_iob->type == id_IOBUF_DCIEN;
CellInfo *obuf = insert_obuf(
int_name(xil_iob->name, (is_se_iobuf || xil_iob->type == id_OBUFT) ? "OBUFT" : "OBUF", !is_se_obuf),
is_se_iobuf ? (has_dci ? id_OBUFT_DCIEN : id_OBUFT) : xil_iob->type, xil_iob->getPort(id_I), pad_net,
xil_iob->getPort(id_T));
std::string tile = ctx->get_tile_type(site.tile).str(ctx);
if (boost::starts_with(tile, "RIOB18"))
ctx->bindBel(uarch->get_site_bel(site, ctx->id("IOB18.OUTBUF_DCIEN")), obuf, STRENGTH_LOCKED);
else
ctx->bindBel(uarch->get_site_bel(site, ctx->id("IOB33.OUTBUF")), obuf, STRENGTH_LOCKED);
xil_iob->movePortTo(id_DCITERMDISABLE, obuf, id_DCITERMDISABLE);
}
bool is_diff_ibuf = xil_iob->type.in(id_IBUFDS, id_IBUFDS_INTERMDISABLE, id_IBUFDS);
bool is_diff_iobuf = xil_iob->type.in(id_IOBUFDS, id_IOBUFDS_DCIEN);
bool is_diff_out_iobuf =
xil_iob->type.in(id_IOBUFDS_DIFF_OUT, id_IOBUFDS_DIFF_OUT_DCIEN, id_IOBUFDS_DIFF_OUT_INTERMDISABLE);
bool is_diff_obuf = xil_iob->type.in(id_OBUFDS, id_OBUFTDS);
if (is_diff_ibuf || is_diff_iobuf) {
NetInfo *pad_p_net = xil_iob->getPort((is_diff_iobuf || is_diff_out_iobuf) ? id_IO : id_I);
NPNR_ASSERT(pad_p_net != nullptr);
auto site_p = pad_site(pad_p_net);
NetInfo *pad_n_net = xil_iob->getPort((is_diff_iobuf || is_diff_out_iobuf) ? id_IOB : id_IB);
NPNR_ASSERT(pad_n_net != nullptr);
std::string tile_p = ctx->get_tile_type(site_p.tile).str(ctx);
bool is_riob18 = boost::starts_with(tile_p, "RIOB18");
if (!is_diff_iobuf && !is_diff_out_iobuf) {
xil_iob->disconnectPort(id_I);
xil_iob->disconnectPort(id_IB);
}
NetInfo *top_out = xil_iob->getPort(id_O);
xil_iob->disconnectPort(id_O);
IdString ibuf_type = id_IBUFDS;
CellInfo *inbuf = insert_diffibuf(int_name(xil_iob->name, "IBUF", is_se_iobuf), ibuf_type,
{pad_p_net, pad_n_net}, top_out);
if (is_riob18) {
ctx->bindBel(uarch->get_site_bel(site_p, ctx->id("IOB18M.INBUF_DCIEN")), inbuf, STRENGTH_LOCKED);
inbuf->attrs[id_X_IOB_SITE_TYPE] = std::string("IOB18M");
} else {
ctx->bindBel(uarch->get_site_bel(site_p, ctx->id("IOB33M.INBUF_EN")), inbuf, STRENGTH_LOCKED);
inbuf->attrs[id_X_IOB_SITE_TYPE] = std::string("IOB33M");
}
}
if (is_diff_obuf || is_diff_out_iobuf || is_diff_iobuf) {
// FIXME: true diff outputs
NetInfo *pad_p_net = xil_iob->getPort((is_diff_iobuf || is_diff_out_iobuf) ? id_IO : id_O);
NPNR_ASSERT(pad_p_net != nullptr);
auto site_p = pad_site(pad_p_net);
NetInfo *pad_n_net = xil_iob->getPort((is_diff_iobuf || is_diff_out_iobuf) ? id_IOB : id_OB);
NPNR_ASSERT(pad_n_net != nullptr);
auto site_n = pad_site(pad_n_net);
std::string tile_p = ctx->get_tile_type(site_p.tile).str(ctx);
bool is_riob18 = boost::starts_with(tile_p, "RIOB18");
xil_iob->disconnectPort((is_diff_iobuf || is_diff_out_iobuf) ? id_IO : id_O);
xil_iob->disconnectPort((is_diff_iobuf || is_diff_out_iobuf) ? id_IOB : id_OB);
NetInfo *inv_i = create_internal_net(xil_iob->name, is_diff_obuf ? "I_B" : "OBUFTDS$subnet$I_B");
CellInfo *inv = insert_outinv(int_name(xil_iob->name, is_diff_obuf ? "INV" : "OBUFTDS$subcell$INV"),
xil_iob->getPort(id_I), inv_i);
if (is_riob18) {
ctx->bindBel(uarch->get_site_bel(site_n, ctx->id("IOB18S.O_ININV")), inv, STRENGTH_LOCKED);
inv->attrs[id_X_IOB_SITE_TYPE] = std::string("IOB18S");
} else {
ctx->bindBel(uarch->get_site_bel(site_n, ctx->id("IOB33S.O_ININV")), inv, STRENGTH_LOCKED);
inv->attrs[id_X_IOB_SITE_TYPE] = std::string("IOB33S");
}
bool has_dci = xil_iob->type.in(id_IOBUFDS_DCIEN, id_IOBUFDSE3);
CellInfo *obuf_p = insert_obuf(int_name(xil_iob->name, is_diff_obuf ? "P" : "OBUFTDS$subcell$P"),
(is_diff_iobuf || is_diff_out_iobuf || (xil_iob->type == id_OBUFTDS))
? (has_dci ? id_OBUFT_DCIEN : id_OBUFT)
: id_OBUF,
xil_iob->getPort(id_I), pad_p_net, xil_iob->getPort(id_T));
if (is_riob18) {
ctx->bindBel(uarch->get_site_bel(site_p, ctx->id("IOB18M.OUTBUF_DCIEN")), obuf_p, STRENGTH_LOCKED);
obuf_p->attrs[id_X_IOB_SITE_TYPE] = std::string("IOB18M");
} else {
ctx->bindBel(uarch->get_site_bel(site_p, ctx->id("IOB33M.OUTBUF")), obuf_p, STRENGTH_LOCKED);
obuf_p->attrs[id_X_IOB_SITE_TYPE] = std::string("IOB33M");
}
obuf_p->connectPort(id_DCITERMDISABLE, xil_iob->getPort(id_DCITERMDISABLE));
CellInfo *obuf_n = insert_obuf(int_name(xil_iob->name, is_diff_obuf ? "N" : "OBUFTDS$subcell$N"),
(is_diff_iobuf || is_diff_out_iobuf || (xil_iob->type == id_OBUFTDS))
? (has_dci ? id_OBUFT_DCIEN : id_OBUFT)
: id_OBUF,
inv_i, pad_n_net, xil_iob->getPort(id_T));
if (is_riob18) {
ctx->bindBel(uarch->get_site_bel(site_n, ctx->id("IOB18S.OUTBUF_DCIEN")), obuf_n, STRENGTH_LOCKED);
obuf_n->attrs[id_X_IOB_SITE_TYPE] = std::string("IOB18S");
} else {
ctx->bindBel(uarch->get_site_bel(site_n, ctx->id("IOB33S.OUTBUF")), obuf_n, STRENGTH_LOCKED);
obuf_n->attrs[id_X_IOB_SITE_TYPE] = std::string("IOB33S");
}
obuf_n->connectPort(id_DCITERMDISABLE, xil_iob->getPort(id_DCITERMDISABLE));
xil_iob->disconnectPort(id_DCITERMDISABLE);
}
}
void XC7Packer::pack_io()
{
log_info("Inserting IO buffers..\n");
get_top_level_pins(ctx, toplevel_ports);
// Insert PAD cells on top level IO, and IO buffers where one doesn't exist already
std::vector<CellInfo *> npnr_io;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (ci->type == ctx->id("$nextpnr_ibuf") || ci->type == ctx->id("$nextpnr_iobuf") ||
ci->type == ctx->id("$nextpnr_obuf"))
npnr_io.push_back(ci);
}
std::vector<std::pair<CellInfo *, PortRef>> pad_and_buf;
for (auto ci : npnr_io) {
pad_and_buf.push_back(insert_pad_and_buf(ci));
}
flush_cells();
pool<BelId> used_io_bels;
int unconstr_io_count = 0;
for (auto &iob : pad_and_buf) {
CellInfo *pad = iob.first;
// Process location constraints
if (pad->attrs.count(id_PACKAGE_PIN)) {
pad->attrs[id_LOC] = pad->attrs.at(id_PACKAGE_PIN);
}
if (pad->attrs.count(id_LOC)) {
std::string loc = pad->attrs.at(id_LOC).to_string();
BelId bel = ctx->get_package_pin_bel(ctx->id(loc));
if (bel == BelId())
log_error("Unable to constrain IO '%s', device does not have a pin named '%s'\n", pad->name.c_str(ctx),
loc.c_str());
log_info(" Constraining '%s' to pad '%s'\n", pad->name.c_str(ctx), ctx->nameOfBel(bel));
pad->attrs[id_BEL] = std::string(ctx->nameOfBel(bel));
}
if (pad->attrs.count(id_BEL)) {
used_io_bels.insert(ctx->getBelByNameStr(pad->attrs.at(id_BEL).as_string()));
} else {
++unconstr_io_count;
}
}
// Constrain unconstrained IO
for (auto &iob : pad_and_buf) {
CellInfo *pad = iob.first;
if (!pad->attrs.count(id_BEL)) {
log_error("FIXME: unconstrained IO not supported (pad %s)\n", ctx->nameOf(pad));
;
}
}
// Decompose macro IO primitives to smaller primitives that map logically to the actual IO Bels
for (auto &iob : pad_and_buf) {
if (packed_cells.count(iob.second.cell->name))
continue;
decompose_iob(iob.second.cell, true, str_or_default(iob.first->attrs, id_IOSTANDARD, ""));
packed_cells.insert(iob.second.cell->name);
}
flush_cells();
dict<IdString, XFormRule> hriobuf_rules, hpiobuf_rules;
hriobuf_rules[id_OBUF].new_type = id_IOB33_OUTBUF;
hriobuf_rules[id_OBUF].port_xform[id_I] = id_IN;
hriobuf_rules[id_OBUF].port_xform[id_O] = id_OUT;
hriobuf_rules[id_OBUF].port_xform[id_T] = id_TRI;
hriobuf_rules[id_OBUFT] = XFormRule(hriobuf_rules[id_OBUF]);
hriobuf_rules[id_IBUF].new_type = id_IOB33_INBUF_EN;
hriobuf_rules[id_IBUF].port_xform[id_I] = id_PAD;
hriobuf_rules[id_IBUF].port_xform[id_O] = id_OUT;
hriobuf_rules[id_IBUF_INTERMDISABLE] = XFormRule(hriobuf_rules[id_IBUF]);
hriobuf_rules[id_IBUF_IBUFDISABLE] = XFormRule(hriobuf_rules[id_IBUF]);
hriobuf_rules[id_IBUFDS_INTERMDISABLE_INT] = XFormRule(hriobuf_rules[id_IBUF]);
hriobuf_rules[id_IBUFDS_INTERMDISABLE_INT].port_xform[id_IB] = id_DIFFI_IN;
hriobuf_rules[id_IBUFDS] = XFormRule(hriobuf_rules[id_IBUF]);
hriobuf_rules[id_IBUFDS].port_xform[id_IB] = id_DIFFI_IN;
hpiobuf_rules[id_OBUF].new_type = id_IOB18_OUTBUF_DCIEN;
hpiobuf_rules[id_OBUF].port_xform[id_I] = id_IN;
hpiobuf_rules[id_OBUF].port_xform[id_O] = id_OUT;
hpiobuf_rules[id_OBUF].port_xform[id_T] = id_TRI;
hpiobuf_rules[id_OBUFT] = XFormRule(hpiobuf_rules[id_OBUF]);
hpiobuf_rules[id_IBUF].new_type = id_IOB18_INBUF_DCIEN;
hpiobuf_rules[id_IBUF].port_xform[id_I] = id_PAD;
hpiobuf_rules[id_IBUF].port_xform[id_O] = id_OUT;
hpiobuf_rules[id_IBUF_INTERMDISABLE] = XFormRule(hpiobuf_rules[id_IBUF]);
hpiobuf_rules[id_IBUF_IBUFDISABLE] = XFormRule(hpiobuf_rules[id_IBUF]);
hriobuf_rules[id_IBUFDS_INTERMDISABLE_INT] = XFormRule(hriobuf_rules[id_IBUF]);
hpiobuf_rules[id_IBUFDS_INTERMDISABLE_INT].port_xform[id_IB] = id_DIFFI_IN;
hpiobuf_rules[id_IBUFDS] = XFormRule(hpiobuf_rules[id_IBUF]);
hpiobuf_rules[id_IBUFDS].port_xform[id_IB] = id_DIFFI_IN;
// Special xform for OBUFx and IBUFx.
dict<IdString, XFormRule> rules;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (!ci->attrs.count(id_BEL) && ci->bel == BelId())
continue;
std::string belname =
ci->attrs.count(id_BEL) ? ci->attrs[id_BEL].as_string() : std::string(ctx->nameOfBel(ci->bel));
size_t pos = belname.find(".");
if (belname.substr(pos + 1, 5) == "IOB18")
rules = hpiobuf_rules;
else if (belname.substr(pos + 1, 5) == "IOB33")
rules = hriobuf_rules;
else
log_error("Unexpected IOBUF BEL %s\n", belname.c_str());
if (rules.count(ci->type)) {
xform_cell(rules, ci);
}
}
dict<IdString, XFormRule> hrio_rules;
hrio_rules[id_PAD].new_type = id_PAD;
hrio_rules[id_INV].new_type = id_INVERTER;
hrio_rules[id_INV].port_xform[id_I] = id_IN;
hrio_rules[id_INV].port_xform[id_O] = id_OUT;
hrio_rules[id_PS7].new_type = id_PS7_PS7;
generic_xform(hrio_rules, true);
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
std::string type = ci->type.str(ctx);
if (!boost::starts_with(type, "IOB33") && !boost::starts_with(type, "IOB18"))
continue;
if (!ci->attrs.count(id_X_IOB_SITE_TYPE))
continue;
type.replace(0, 5, ci->attrs.at(id_X_IOB_SITE_TYPE).as_string());
ci->type = ctx->id(type);
}
// check all PAD cells for IOSTANDARD/DRIVE
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
std::string type = ci->type.str(ctx);
if (type != "PAD")
continue;
check_valid_pad(ci, type);
}
}
void XC7Packer::check_valid_pad(CellInfo *ci, std::string type)
{
auto iostandard_id = id_IOSTANDARD;
auto iostandard_attr = ci->attrs.find(iostandard_id);
if (iostandard_attr == ci->attrs.end())
log_error("port %s has no IOSTANDARD property", ci->name.c_str(ctx));
auto iostandard = iostandard_attr->second.as_string();
if (!boost::starts_with(iostandard, "LVTTL") && !boost::starts_with(iostandard, "LVCMOS"))
return;
auto drive_attr = ci->attrs.find(id_DRIVE);
// no drive strength attribute: use default
if (drive_attr == ci->attrs.end())
return;
auto drive = drive_attr->second.as_int64();
bool is_iob33 = boost::starts_with(type, "IOB33");
if (is_iob33) {
if (drive == 4 || drive == 8 || drive == 12)
return;
if (iostandard != "LVCMOS12" && drive == 16)
return;
if ((iostandard == "LVCMOS18" || iostandard == "LVTTL") && drive == 24)
return;
} else { // IOB18
if (drive == 2 || drive == 4 || drive == 6 || drive == 8)
return;
if (iostandard != "LVCMOS12" && (drive == 12 || drive == 16))
return;
}
log_error("unsupported DRIVE strength property %s for port %s", drive_attr->second.c_str(), ci->name.c_str(ctx));
}
NEXTPNR_NAMESPACE_END