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ecp5: Support code for carry chain handling

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-09-30 16:58:02 +01:00
parent a27c7b45de
commit 2628344298
2 changed files with 118 additions and 16 deletions
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22
ecp5/cells.cc
View File

@ -124,6 +124,28 @@ std::unique_ptr<CellInfo> create_ecp5_cell(Context *ctx, IdString type, std::str
add_port(ctx, new_cell.get(), "C", PORT_IN);
add_port(ctx, new_cell.get(), "D", PORT_IN);
add_port(ctx, new_cell.get(), "Z", PORT_OUT);
} else if (type == ctx->id("CCU2C")) {
new_cell->params[ctx->id("INIT0")] = "0";
new_cell->params[ctx->id("INIT1")] = "0";
new_cell->params[ctx->id("INJECT1_0")] = "YES";
new_cell->params[ctx->id("INJECT1_1")] = "YES";
add_port(ctx, new_cell.get(), "CIN", PORT_IN);
add_port(ctx, new_cell.get(), "A0", PORT_IN);
add_port(ctx, new_cell.get(), "B0", PORT_IN);
add_port(ctx, new_cell.get(), "C0", PORT_IN);
add_port(ctx, new_cell.get(), "D0", PORT_IN);
add_port(ctx, new_cell.get(), "A1", PORT_IN);
add_port(ctx, new_cell.get(), "B1", PORT_IN);
add_port(ctx, new_cell.get(), "C1", PORT_IN);
add_port(ctx, new_cell.get(), "D1", PORT_IN);
add_port(ctx, new_cell.get(), "S0", PORT_OUT);
add_port(ctx, new_cell.get(), "S1", PORT_OUT);
add_port(ctx, new_cell.get(), "COUT", PORT_OUT);
} else if (type == ctx->id("DCCA")) {
add_port(ctx, new_cell.get(), "CLKI", PORT_IN);
add_port(ctx, new_cell.get(), "CLKO", PORT_OUT);

112
ecp5/pack.cc
View File

@ -22,6 +22,7 @@
#include <iterator>
#include <unordered_set>
#include "cells.h"
#include "chain_utils.h"
#include "design_utils.h"
#include "log.h"
#include "util.h"
@ -106,6 +107,26 @@ class Ecp5Packer
return true;
}
// Return whether or not an FF can be added to a tile (pairing checks must also be done using the fn above)
bool can_add_ff_to_file(const std::vector<CellInfo *> &tile_ffs, CellInfo *ff0) {
for (const auto &existing : tile_ffs) {
if (net_or_nullptr(existing, ctx->id("CLK")) != net_or_nullptr(ff0, ctx->id("CLK")))
return false;
if (net_or_nullptr(existing, ctx->id("LSR")) != net_or_nullptr(ff0, ctx->id("LSR")))
return false;
if (str_or_default(existing->params, ctx->id("CLKMUX"), "CLK") !=
str_or_default(ff0->params, ctx->id("CLKMUX"), "CLK"))
return false;
if (str_or_default(existing->params, ctx->id("LSRMUX"), "LSR") !=
str_or_default(ff0->params, ctx->id("LSRMUX"), "LSR"))
return false;
if (str_or_default(existing->params, ctx->id("LSRMUX"), "LSR") !=
str_or_default(ff0->params, ctx->id("LSRMUX"), "LSR"))
return false;
}
return true;
}
// Return true if two LUTs can be paired considering FF compatibility
bool can_pack_lutff(IdString lut0, IdString lut1)
{
@ -315,11 +336,10 @@ class Ecp5Packer
// Create a feed in to the carry chain
CellInfo *make_carry_feed_in(NetInfo *carry, PortRef chain_in)
{
std::unique_ptr<CellInfo> feedin = create_ecp5_cell(ctx, ctx->id("TRELLIS_SLICE"));
std::unique_ptr<CellInfo> feedin = create_ecp5_cell(ctx, ctx->id("CCU2C"));
feedin->params[ctx->id("MODE")] = "CCU2";
feedin->params[ctx->id("LUT0_INITVAL")] = "10"; // LUT4 = 0; LUT2 = A
feedin->params[ctx->id("LUT1_INITVAL")] = "65535";
feedin->params[ctx->id("INIT0")] = "10"; // LUT4 = 0; LUT2 = A
feedin->params[ctx->id("INIT1")] = "65535";
feedin->params[ctx->id("INJECT1_0")] = "NO";
feedin->params[ctx->id("INJECT1_1")] = "YES";
@ -331,8 +351,8 @@ class Ecp5Packer
connect_port(ctx, carry, feedin.get(), id_A0);
std::unique_ptr<NetInfo> new_carry(new NetInfo());
new_carry->name = ctx->id(feedin->name.str(ctx) + "$FCO");
connect_port(ctx, new_carry.get(), feedin.get(), id_FCO);
new_carry->name = ctx->id(feedin->name.str(ctx) + "$COUT");
connect_port(ctx, new_carry.get(), feedin.get(), ctx->id("COUT"));
connect_port(ctx, new_carry.get(), chain_in.cell, chain_in.port);
CellInfo *feedin_ptr = feedin.get();
@ -343,24 +363,23 @@ class Ecp5Packer
}
// Create a feed out and loop through from the carry chain
CellInfo *make_carry_feed_out(NetInfo *carry, boost::optional<PortRef> chain_next)
CellInfo *make_carry_feed_out(NetInfo *carry, boost::optional<PortRef> chain_next = boost::optional<PortRef>())
{
std::unique_ptr<CellInfo> feedout = create_ecp5_cell(ctx, ctx->id("TRELLIS_SLICE"));
feedout->params[ctx->id("MODE")] = "CCU2";
feedout->params[ctx->id("LUT0_INITVAL")] = "0";
feedout->params[ctx->id("LUT1_INITVAL")] = "10"; // LUT4 = 0; LUT2 = A
std::unique_ptr<CellInfo> feedout = create_ecp5_cell(ctx, ctx->id("CCU2C"));
feedout->params[ctx->id("INIT0")] = "0";
feedout->params[ctx->id("INIT1")] = "10"; // LUT4 = 0; LUT2 = A
feedout->params[ctx->id("INJECT1_0")] = "YES";
feedout->params[ctx->id("INJECT1_1")] = "NO";
PortRef carry_drv = carry->driver;
carry->driver.cell = nullptr;
connect_port(ctx, carry, feedout.get(), id_F0);
connect_port(ctx, carry, feedout.get(), ctx->id("S0"));
std::unique_ptr<NetInfo> new_cin(new NetInfo());
new_cin->name = ctx->id(feedout->name.str(ctx) + "$FCI");
new_cin->name = ctx->id(feedout->name.str(ctx) + "$CIN");
new_cin->driver = carry_drv;
carry_drv.cell->ports.at(carry_drv.port).net = new_cin.get();
connect_port(ctx, new_cin.get(), feedout.get(), id_FCI);
connect_port(ctx, new_cin.get(), feedout.get(), ctx->id("CIN"));
if (chain_next) {
// Loop back into LUT4_1 for feedthrough
@ -373,7 +392,8 @@ class Ecp5Packer
carry->users.end());
std::unique_ptr<NetInfo> new_cout(new NetInfo());
new_cout->name = ctx->id(feedout->name.str(ctx) + "$FCO");
new_cout->name = ctx->id(feedout->name.str(ctx) + "$COUT");
connect_port(ctx, new_cout.get(), feedout.get(), ctx->id("COUT"));
chain_next->cell->ports[chain_next->port].net = nullptr;
connect_port(ctx, new_cout.get(), chain_next->cell, chain_next->port);
@ -391,8 +411,68 @@ class Ecp5Packer
return feedout_ptr;
}
// Split a carry chain into multiple legal chains
std::vector<CellChain> split_carry_chain(CellChain &carryc)
{
bool start_of_chain = true;
std::vector<CellChain> chains;
const int max_length = (ctx->chip_info->width - 4) * 4 - 2;
auto curr_cell = carryc.cells.begin();
while (curr_cell != carryc.cells.end()) {
CellInfo *cell = *curr_cell;
if (start_of_chain) {
chains.emplace_back();
start_of_chain = false;
if (cell->ports.at(ctx->id("CIN")).net) {
// CIN is not constant and not part of a chain. Must feed in from fabric
PortRef inport;
inport.cell = cell;
inport.port = ctx->id("CIN");
CellInfo *feedin = make_carry_feed_in(cell->ports.at(ctx->id("CIN")).net, inport);
chains.back().cells.push_back(feedin);
}
}
chains.back().cells.push_back(cell);
bool split_chain = int(chains.back().cells.size()) > max_length;
if (split_chain) {
CellInfo *passout = make_carry_feed_out(cell->ports.at(ctx->id("COUT")).net);
chains.back().cells.back() = passout;
start_of_chain = true;
} else {
NetInfo *carry_net = cell->ports.at(ctx->id("COUT")).net;
bool at_end = (curr_cell == carryc.cells.end() - 1);
if (carry_net != nullptr && (carry_net->users.size() > 1 || at_end)) {
boost::optional<PortRef> nextport;
if (!at_end) {
auto next_cell = *(curr_cell + 1);
PortRef nextpr;
nextpr.cell = next_cell;
nextpr.port = ctx->id("CIN");
nextport = nextpr;
}
CellInfo *passout = make_carry_feed_out(cell->ports.at(ctx->id("COUT")).net, nextport);
chains.back().cells.push_back(passout);
}
++curr_cell;
}
}
return chains;
}
// Pack carries and set up appropriate relative constraints
void pack_carries() { log_info("Packing carries...\n"); }
void pack_carries() {
log_info("Packing carries...\n");
auto chains = find_chains(ctx, [](const Context *ctx, const CellInfo *cell) {
return is_carry(ctx, cell);
}, [](const Context *ctx, const CellInfo *cell) {
return net_driven_by(ctx, cell->ports.at(ctx->id("CIN")).net, is_carry, ctx->id("COUT"));
}, [](const Context *ctx, const CellInfo *cell) {
return net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_carry,
ctx->id("CIN"), false);
}, 1);
}
// Pack LUTs that have been paired together
void pack_lut_pairs()