nextpnr/ice40/pack.cc
David Shah 998ab2b20a ice40: Fixing the carry packer for a larger design
Signed-off-by: David Shah <davey1576@gmail.com>
2018-06-27 12:43:29 +02:00

584 lines
23 KiB
C++

/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 Clifford Wolf <clifford@symbioticeda.com>
* Copyright (C) 2018 David Shah <david@symbioticeda.com>
*
* 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 "pack.h"
#include <algorithm>
#include <unordered_set>
#include "cells.h"
#include "design_utils.h"
#include "log.h"
#include "util.h"
NEXTPNR_NAMESPACE_BEGIN
// Pack LUTs and LUT-FF pairs
static void pack_lut_lutffs(Context *ctx)
{
log_info("Packing LUT-FFs..\n");
std::unordered_set<IdString> packed_cells;
std::vector<std::unique_ptr<CellInfo>> new_cells;
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (ctx->verbose)
log_info("cell '%s' is of type '%s'\n", ci->name.c_str(ctx), ci->type.c_str(ctx));
if (is_lut(ctx, ci)) {
std::unique_ptr<CellInfo> packed = create_ice_cell(ctx, ctx->id("ICESTORM_LC"), ci->name.str(ctx) + "_LC");
std::copy(ci->attrs.begin(), ci->attrs.end(), std::inserter(packed->attrs, packed->attrs.begin()));
packed_cells.insert(ci->name);
if (ctx->verbose)
log_info("packed cell %s into %s\n", ci->name.c_str(ctx), packed->name.c_str(ctx));
// See if we can pack into a DFF
// TODO: LUT cascade
NetInfo *o = ci->ports.at(ctx->id("O")).net;
CellInfo *dff = net_only_drives(ctx, o, is_ff, ctx->id("D"), true);
auto lut_bel = ci->attrs.find(ctx->id("BEL"));
bool packed_dff = false;
if (dff) {
if (ctx->verbose)
log_info("found attached dff %s\n", dff->name.c_str(ctx));
auto dff_bel = dff->attrs.find(ctx->id("BEL"));
if (lut_bel != ci->attrs.end() && dff_bel != dff->attrs.end() && lut_bel->second != dff_bel->second) {
// Locations don't match, can't pack
} else {
lut_to_lc(ctx, ci, packed.get(), false);
dff_to_lc(ctx, dff, packed.get(), false);
ctx->nets.erase(o->name);
if (dff_bel != dff->attrs.end())
packed->attrs[ctx->id("BEL")] = dff_bel->second;
packed_cells.insert(dff->name);
if (ctx->verbose)
log_info("packed cell %s into %s\n", dff->name.c_str(ctx), packed->name.c_str(ctx));
packed_dff = true;
}
}
if (!packed_dff) {
lut_to_lc(ctx, ci, packed.get(), true);
}
new_cells.push_back(std::move(packed));
}
}
for (auto pcell : packed_cells) {
ctx->cells.erase(pcell);
}
for (auto &ncell : new_cells) {
ctx->cells[ncell->name] = std::move(ncell);
}
}
// Pack FFs not packed as LUTFFs
static void pack_nonlut_ffs(Context *ctx)
{
log_info("Packing non-LUT FFs..\n");
std::unordered_set<IdString> packed_cells;
std::vector<std::unique_ptr<CellInfo>> new_cells;
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_ff(ctx, ci)) {
std::unique_ptr<CellInfo> packed =
create_ice_cell(ctx, ctx->id("ICESTORM_LC"), ci->name.str(ctx) + "_DFFLC");
std::copy(ci->attrs.begin(), ci->attrs.end(), std::inserter(packed->attrs, packed->attrs.begin()));
if (ctx->verbose)
log_info("packed cell %s into %s\n", ci->name.c_str(ctx), packed->name.c_str(ctx));
packed_cells.insert(ci->name);
dff_to_lc(ctx, ci, packed.get(), true);
new_cells.push_back(std::move(packed));
}
}
for (auto pcell : packed_cells) {
ctx->cells.erase(pcell);
}
for (auto &ncell : new_cells) {
ctx->cells[ncell->name] = std::move(ncell);
}
}
static bool net_is_constant(const Context *ctx, NetInfo *net, bool &value)
{
if (net == nullptr)
return false;
if (net->name == ctx->id("$PACKER_GND_NET") || net->name == ctx->id("$PACKER_VCC_NET")) {
value = (net->name == ctx->id("$PACKER_VCC_NET"));
return true;
} else {
return false;
}
}
// Pack carry logic
static void pack_carries(Context *ctx)
{
log_info("Packing carries..\n");
std::unordered_set<IdString> packed_cells;
std::vector<std::unique_ptr<CellInfo>> new_cells;
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_carry(ctx, ci)) {
packed_cells.insert(cell.first);
CellInfo *carry_ci_lc;
bool ci_value;
bool ci_const = net_is_constant(ctx, ci->ports.at(ctx->id("CI")).net, ci_value);
if (ci_const) {
carry_ci_lc = nullptr;
} else {
carry_ci_lc = net_only_drives(ctx, ci->ports.at(ctx->id("CI")).net, is_lc, ctx->id("I3"), false);
}
std::set<IdString> i0_matches, i1_matches;
NetInfo *i0_net = ci->ports.at(ctx->id("I0")).net;
NetInfo *i1_net = ci->ports.at(ctx->id("I1")).net;
// Find logic cells connected to both I0 and I1
if (i0_net) {
for (auto usr : i0_net->users) {
if (is_lc(ctx, usr.cell) && usr.port == ctx->id("I1")) {
i0_matches.insert(usr.cell->name);
if (!i1_net) {
// I1 is don't care when disconnected, duplicate I0
i1_matches.insert(usr.cell->name);
}
}
}
}
if (i1_net) {
for (auto usr : i1_net->users) {
if (is_lc(ctx, usr.cell) && usr.port == ctx->id("I2")) {
i1_matches.insert(usr.cell->name);
if (!i0_net) {
// I0 is don't care when disconnected, duplicate I1
i0_matches.insert(usr.cell->name);
}
}
}
}
std::set<IdString> carry_lcs;
std::set_intersection(i0_matches.begin(), i0_matches.end(), i1_matches.begin(), i1_matches.end(),
std::inserter(carry_lcs, carry_lcs.end()));
CellInfo *carry_lc = nullptr;
if (carry_ci_lc && carry_lcs.find(carry_ci_lc->name) != carry_lcs.end()) {
carry_lc = carry_ci_lc;
} else {
if (carry_lcs.empty()) {
// No LC to pack into matching I0/I1, insert a new one
std::unique_ptr<CellInfo> created_lc =
create_ice_cell(ctx, ctx->id("ICESTORM_LC"), cell.first.str(ctx) + "$CARRY");
carry_lc = created_lc.get();
created_lc->ports.at(ctx->id("I1")).net = i0_net;
if (i0_net) {
PortRef pr;
pr.cell = created_lc.get();
pr.port = ctx->id("I1");
i0_net->users.push_back(pr);
}
created_lc->ports.at(ctx->id("I2")).net = i1_net;
if (i1_net) {
PortRef pr;
pr.cell = created_lc.get();
pr.port = ctx->id("I2");
i1_net->users.push_back(pr);
}
new_cells.push_back(std::move(created_lc));
} else {
IdString lc_name = *carry_lcs.begin();
if (ctx->cells.find(lc_name) != ctx->cells.end()) {
carry_lc = ctx->cells.at(lc_name).get();
} else {
// Name might not be found in the Context, if it is a new cell
auto new_pack =
std::find_if(new_cells.begin(), new_cells.end(),
[lc_name](std::unique_ptr<CellInfo> &nc) { return nc->name == lc_name; });
assert(new_pack != new_cells.end());
carry_lc = new_pack->get();
}
}
}
carry_lc->params[ctx->id("CARRY_ENABLE")] = "1";
replace_port(ci, ctx->id("CI"), carry_lc, ctx->id("CIN"));
replace_port(ci, ctx->id("CO"), carry_lc, ctx->id("COUT"));
if (i0_net) {
auto &i0_usrs = i0_net->users;
i0_usrs.erase(std::remove_if(i0_usrs.begin(), i0_usrs.end(), [ci, ctx](const PortRef &pr) {
return pr.cell == ci && pr.port == ctx->id("I0");
}));
}
if (i1_net) {
auto &i1_usrs = i1_net->users;
i1_usrs.erase(std::remove_if(i1_usrs.begin(), i1_usrs.end(), [ci, ctx](const PortRef &pr) {
return pr.cell == ci && pr.port == ctx->id("I1");
}));
}
// Check for constant driver on CIN
if (carry_lc->ports.at(ctx->id("CIN")).net != nullptr) {
IdString cin_net = carry_lc->ports.at(ctx->id("CIN")).net->name;
if (cin_net == ctx->id("$PACKER_GND_NET") || cin_net == ctx->id("$PACKER_VCC_NET")) {
carry_lc->params[ctx->id("CIN_CONST")] = "1";
carry_lc->params[ctx->id("CIN_SET")] = cin_net == ctx->id("$PACKER_VCC_NET") ? "1" : "0";
carry_lc->ports.at(ctx->id("CIN")).net = nullptr;
auto &cin_users = ctx->nets.at(cin_net)->users;
cin_users.erase(
std::remove_if(cin_users.begin(), cin_users.end(), [carry_lc, ctx](const PortRef &pr) {
return pr.cell == carry_lc && pr.port == ctx->id("CIN");
}));
}
}
}
}
for (auto pcell : packed_cells) {
ctx->cells.erase(pcell);
}
for (auto &ncell : new_cells) {
ctx->cells[ncell->name] = std::move(ncell);
}
}
// "Pack" RAMs
static void pack_ram(Context *ctx)
{
log_info("Packing RAMs..\n");
std::unordered_set<IdString> packed_cells;
std::vector<std::unique_ptr<CellInfo>> new_cells;
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_ram(ctx, ci)) {
std::unique_ptr<CellInfo> packed =
create_ice_cell(ctx, ctx->id("ICESTORM_RAM"), ci->name.str(ctx) + "_RAM");
packed_cells.insert(ci->name);
for (auto param : ci->params)
packed->params[param.first] = param.second;
packed->params[ctx->id("NEG_CLK_W")] =
std::to_string(ci->type == ctx->id("SB_RAM40_4KNW") || ci->type == ctx->id("SB_RAM40_4KNRNW"));
packed->params[ctx->id("NEG_CLK_R")] =
std::to_string(ci->type == ctx->id("SB_RAM40_4KNR") || ci->type == ctx->id("SB_RAM40_4KNRNW"));
packed->type = ctx->id("ICESTORM_RAM");
for (auto port : ci->ports) {
PortInfo &pi = port.second;
std::string newname = pi.name.str(ctx);
size_t bpos = newname.find('[');
if (bpos != std::string::npos) {
newname = newname.substr(0, bpos) + "_" + newname.substr(bpos + 1, (newname.size() - bpos) - 2);
}
replace_port(ci, ctx->id(pi.name.c_str(ctx)), packed.get(), ctx->id(newname));
}
new_cells.push_back(std::move(packed));
}
}
for (auto pcell : packed_cells) {
ctx->cells.erase(pcell);
}
for (auto &ncell : new_cells) {
ctx->cells[ncell->name] = std::move(ncell);
}
}
// Merge a net into a constant net
static void set_net_constant(const Context *ctx, NetInfo *orig, NetInfo *constnet, bool constval)
{
orig->driver.cell = nullptr;
for (auto user : orig->users) {
if (user.cell != nullptr) {
CellInfo *uc = user.cell;
if (ctx->verbose)
log_info("%s user %s\n", orig->name.c_str(ctx), uc->name.c_str(ctx));
if ((is_lut(ctx, uc) || is_lc(ctx, uc) || is_carry(ctx, uc)) && (user.port.str(ctx).at(0) == 'I') &&
!constval) {
uc->ports[user.port].net = nullptr;
} else {
uc->ports[user.port].net = constnet;
constnet->users.push_back(user);
}
}
}
orig->users.clear();
}
// Pack constants (simple implementation)
static void pack_constants(Context *ctx)
{
log_info("Packing constants..\n");
std::unique_ptr<CellInfo> gnd_cell = create_ice_cell(ctx, ctx->id("ICESTORM_LC"), "$PACKER_GND");
gnd_cell->params[ctx->id("LUT_INIT")] = "0";
std::unique_ptr<NetInfo> gnd_net = std::unique_ptr<NetInfo>(new NetInfo);
gnd_net->name = ctx->id("$PACKER_GND_NET");
gnd_net->driver.cell = gnd_cell.get();
gnd_net->driver.port = ctx->id("O");
std::unique_ptr<CellInfo> vcc_cell = create_ice_cell(ctx, ctx->id("ICESTORM_LC"), "$PACKER_VCC");
vcc_cell->params[ctx->id("LUT_INIT")] = "1";
std::unique_ptr<NetInfo> vcc_net = std::unique_ptr<NetInfo>(new NetInfo);
vcc_net->name = ctx->id("$PACKER_VCC_NET");
vcc_net->driver.cell = vcc_cell.get();
vcc_net->driver.port = ctx->id("O");
std::vector<IdString> dead_nets;
bool gnd_used = false;
for (auto net : sorted(ctx->nets)) {
NetInfo *ni = net.second;
if (ni->driver.cell != nullptr && ni->driver.cell->type == ctx->id("GND")) {
IdString drv_cell = ni->driver.cell->name;
set_net_constant(ctx, ni, gnd_net.get(), false);
gnd_used = true;
dead_nets.push_back(net.first);
ctx->cells.erase(drv_cell);
} else if (ni->driver.cell != nullptr && ni->driver.cell->type == ctx->id("VCC")) {
IdString drv_cell = ni->driver.cell->name;
set_net_constant(ctx, ni, vcc_net.get(), true);
dead_nets.push_back(net.first);
ctx->cells.erase(drv_cell);
}
}
if (gnd_used) {
ctx->cells[gnd_cell->name] = std::move(gnd_cell);
ctx->nets[gnd_net->name] = std::move(gnd_net);
}
// Vcc cell always inserted for now, as it may be needed during carry legalisation (TODO: trim later if actually
// never used?)
ctx->cells[vcc_cell->name] = std::move(vcc_cell);
ctx->nets[vcc_net->name] = std::move(vcc_net);
for (auto dn : dead_nets) {
ctx->nets.erase(dn);
}
}
static bool is_nextpnr_iob(Context *ctx, CellInfo *cell)
{
return cell->type == ctx->id("$nextpnr_ibuf") || cell->type == ctx->id("$nextpnr_obuf") ||
cell->type == ctx->id("$nextpnr_iobuf");
}
// Pack IO buffers
static void pack_io(Context *ctx)
{
std::unordered_set<IdString> packed_cells;
std::vector<std::unique_ptr<CellInfo>> new_cells;
log_info("Packing IOs..\n");
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_nextpnr_iob(ctx, ci)) {
CellInfo *sb = nullptr;
if (ci->type == ctx->id("$nextpnr_ibuf") || ci->type == ctx->id("$nextpnr_iobuf")) {
sb = net_only_drives(ctx, ci->ports.at(ctx->id("O")).net, is_sb_io, ctx->id("PACKAGE_PIN"), true, ci);
} else if (ci->type == ctx->id("$nextpnr_obuf")) {
sb = net_only_drives(ctx, ci->ports.at(ctx->id("I")).net, is_sb_io, ctx->id("PACKAGE_PIN"), true, ci);
}
if (sb != nullptr) {
// Trivial case, SB_IO used. Just destroy the net and the
// iobuf
log_info("%s feeds SB_IO %s, removing %s %s.\n", ci->name.c_str(ctx), sb->name.c_str(ctx),
ci->type.c_str(ctx), ci->name.c_str(ctx));
NetInfo *net = sb->ports.at(ctx->id("PACKAGE_PIN")).net;
if (net != nullptr) {
ctx->nets.erase(net->name);
sb->ports.at(ctx->id("PACKAGE_PIN")).net = nullptr;
}
} else {
// Create a SB_IO buffer
std::unique_ptr<CellInfo> ice_cell =
create_ice_cell(ctx, ctx->id("SB_IO"), ci->name.str(ctx) + "$sb_io");
nxio_to_sb(ctx, ci, ice_cell.get());
new_cells.push_back(std::move(ice_cell));
sb = new_cells.back().get();
}
packed_cells.insert(ci->name);
std::copy(ci->attrs.begin(), ci->attrs.end(), std::inserter(sb->attrs, sb->attrs.begin()));
}
}
for (auto pcell : packed_cells) {
ctx->cells.erase(pcell);
}
for (auto &ncell : new_cells) {
ctx->cells[ncell->name] = std::move(ncell);
}
}
static void insert_global(Context *ctx, NetInfo *net, bool is_reset, bool is_cen)
{
std::string glb_name = net->name.str(ctx) + std::string("_$glb_") + (is_reset ? "sr" : (is_cen ? "ce" : "clk"));
std::unique_ptr<CellInfo> gb = create_ice_cell(ctx, ctx->id("SB_GB"), "$gbuf_" + glb_name);
gb->ports[ctx->id("USER_SIGNAL_TO_GLOBAL_BUFFER")].net = net;
PortRef pr;
pr.cell = gb.get();
pr.port = ctx->id("USER_SIGNAL_TO_GLOBAL_BUFFER");
net->users.push_back(pr);
pr.cell = gb.get();
pr.port = ctx->id("GLOBAL_BUFFER_OUTPUT");
std::unique_ptr<NetInfo> glbnet = std::unique_ptr<NetInfo>(new NetInfo());
glbnet->name = ctx->id(glb_name);
glbnet->driver = pr;
gb->ports[ctx->id("GLOBAL_BUFFER_OUTPUT")].net = glbnet.get();
std::vector<PortRef> keep_users;
for (auto user : net->users) {
if (is_clock_port(ctx, user) || (is_reset && is_reset_port(ctx, user)) ||
(is_cen && is_enable_port(ctx, user))) {
user.cell->ports[user.port].net = glbnet.get();
glbnet->users.push_back(user);
} else {
keep_users.push_back(user);
}
}
net->users = keep_users;
ctx->nets[glbnet->name] = std::move(glbnet);
ctx->cells[gb->name] = std::move(gb);
}
// Simple global promoter (clock only)
static void promote_globals(Context *ctx)
{
log_info("Promoting globals..\n");
std::map<IdString, int> clock_count, reset_count, cen_count;
for (auto net : sorted(ctx->nets)) {
NetInfo *ni = net.second;
if (ni->driver.cell != nullptr && !ctx->isGlobalNet(ni)) {
clock_count[net.first] = 0;
reset_count[net.first] = 0;
cen_count[net.first] = 0;
for (auto user : ni->users) {
if (is_clock_port(ctx, user))
clock_count[net.first]++;
if (is_reset_port(ctx, user))
reset_count[net.first]++;
if (is_enable_port(ctx, user))
cen_count[net.first]++;
}
}
}
int prom_globals = 0, prom_resets = 0, prom_cens = 0;
int gbs_available = 8;
for (auto &cell : ctx->cells)
if (is_gbuf(ctx, cell.second.get()))
--gbs_available;
while (prom_globals < gbs_available) {
auto global_clock = std::max_element(clock_count.begin(), clock_count.end(),
[](const std::pair<IdString, int> &a, const std::pair<IdString, int> &b) {
return a.second < b.second;
});
auto global_reset = std::max_element(reset_count.begin(), reset_count.end(),
[](const std::pair<IdString, int> &a, const std::pair<IdString, int> &b) {
return a.second < b.second;
});
auto global_cen = std::max_element(cen_count.begin(), cen_count.end(),
[](const std::pair<IdString, int> &a, const std::pair<IdString, int> &b) {
return a.second < b.second;
});
if (global_reset->second > global_clock->second && prom_resets < 4) {
NetInfo *rstnet = ctx->nets[global_reset->first].get();
insert_global(ctx, rstnet, true, false);
++prom_globals;
++prom_resets;
clock_count.erase(rstnet->name);
reset_count.erase(rstnet->name);
cen_count.erase(rstnet->name);
} else if (global_cen->second > global_clock->second && prom_cens < 4) {
NetInfo *cennet = ctx->nets[global_cen->first].get();
insert_global(ctx, cennet, false, true);
++prom_globals;
++prom_cens;
clock_count.erase(cennet->name);
reset_count.erase(cennet->name);
cen_count.erase(cennet->name);
} else if (global_clock->second != 0) {
NetInfo *clknet = ctx->nets[global_clock->first].get();
insert_global(ctx, clknet, false, false);
++prom_globals;
clock_count.erase(clknet->name);
reset_count.erase(clknet->name);
cen_count.erase(clknet->name);
} else {
break;
}
}
}
// Pack internal oscillators
static void pack_intosc(Context *ctx)
{
log_info("Packing oscillators..\n");
std::unordered_set<IdString> packed_cells;
std::vector<std::unique_ptr<CellInfo>> new_cells;
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_sb_lfosc(ctx, ci)) {
std::unique_ptr<CellInfo> packed =
create_ice_cell(ctx, ctx->id("ICESTORM_LFOSC"), ci->name.str(ctx) + "_OSC");
packed_cells.insert(ci->name);
replace_port(ci, ctx->id("CLKLFEN"), packed.get(), ctx->id("CLKLFEN"));
replace_port(ci, ctx->id("CLKLFPU"), packed.get(), ctx->id("CLKLFPU"));
if (bool_or_default(ci->attrs, ctx->id("ROUTE_THROUGH_FABRIC"))) {
replace_port(ci, ctx->id("CLKLF"), packed.get(), ctx->id("CLKLF_FABRIC"));
} else {
replace_port(ci, ctx->id("CLKLF"), packed.get(), ctx->id("CLKLF"));
}
new_cells.push_back(std::move(packed));
}
}
for (auto pcell : packed_cells) {
ctx->cells.erase(pcell);
}
for (auto &ncell : new_cells) {
ctx->cells[ncell->name] = std::move(ncell);
}
}
// Main pack function
bool pack_design(Context *ctx)
{
try {
log_break();
pack_constants(ctx);
promote_globals(ctx);
pack_io(ctx);
pack_lut_lutffs(ctx);
pack_nonlut_ffs(ctx);
pack_carries(ctx);
pack_ram(ctx);
pack_intosc(ctx);
log_info("Checksum: 0x%08x\n", ctx->checksum());
return true;
} catch (log_execution_error_exception) {
return false;
}
}
NEXTPNR_NAMESPACE_END