ice40: A slightly nicer way to do this.

1 files changed, 31 insertions, 46 deletions

diff --git a/ice40/bitstream.cc b/ice40/bitstream.cc
index 2ee8a294..c388fe2b 100644
--- a/ice40/bitstream.cc
+++ b/ice40/bitstream.cc
@@ -444,55 +444,40 @@ void write_asc(const Context *ctx, std::ostream &out)
                 if (port.second.net == nullptr)

                     continue;

 

-                // Find SB_IO Bel in net that's driving a wire. That's the one

-                // we're routing the signal through.

-                // TODO(q3k): Is there a nicer way to do this?

-                bool found = false;

-

-                // For every wire in the PLLOUT net...

-                for (auto wp : port.second.net->wires) {

-                    // ... get its' uphill bel ...

-                    auto bel = ctx->getBelPinUphill(wp.first).bel;

-                    if (bel == BelId()) {

-                        continue;

-                    }

-                    // ... and check if it's an SB_IO.

-                    if (ctx->getBelType(bel) != TYPE_SB_IO)

-                        continue;

+                // Get IO Bel that this PLL port goes through.

+                // We navigate one pip downhill to the next wire (there should

+                // be only one). Then, the bel that drives that wire should be

+                // the SB_IO that we're looking for.

+                auto wire = ctx->getBelPinWire(cell.second->bel, ctx->portPinFromId(port.second.name));

+                auto pips = ctx->getPipsDownhill(wire).begin();

+                auto driven_wire = ctx->getPipDstWire(*pips);

+                auto io_bel = ctx->chip_info->wire_data[driven_wire.index].bel_uphill.bel_index;

+                auto io_beli = ctx->chip_info->bel_data[io_bel];

+                NPNR_ASSERT(io_beli.type == TYPE_SB_IO);

+

+                // Check that this SB_IO is either unused or just used as an output.

+                auto io_loc = Loc(io_beli.x, io_beli.y, io_beli.z);

+                if (sb_io_used_by_user.count(io_loc)) {

+                    log_error("SB_IO '%s' already in use, cannot route PLL through\n",

+                            ctx->getBelName(bel).c_str(ctx));

+                }

+                sb_io_used_by_pll.insert(Loc(io_beli.x, io_beli.y, io_beli.z));

 

-                    // Check that this SB_IO is either unused or just used as an output.

-                    const BelInfoPOD &io_beli = ci.bel_data[bel.index];

-                    auto io_loc = Loc(io_beli.x, io_beli.y, io_beli.z);

+                // Get IE/REN config location (cf. http://www.clifford.at/icestorm/io_tile.html)

+                auto ieren = get_ieren(bi, io_beli.x, io_beli.y, io_beli.z);

+                int iex, iey, iez;

+                std::tie(iex, iey, iez) = ieren;

+                NPNR_ASSERT(iez != -1);

 

-                    if (sb_io_used_by_user.count(io_loc)) {

-                        log_error("SB_IO '%s' already in use, cannot route PLL through\n",

-                                ctx->getBelName(bel).c_str(ctx));

-                    }

-                    sb_io_used_by_pll.insert(Loc(io_beli.x, io_beli.y, io_beli.z));

-

-                    // Get IE/REN config location (cf. http://www.clifford.at/icestorm/io_tile.html)

-                    auto ieren = get_ieren(bi, io_beli.x, io_beli.y, io_beli.z);

-                    int iex, iey, iez;

-                    std::tie(iex, iey, iez) = ieren;

-                    NPNR_ASSERT(iez != -1);

-

-                    // Write config.

-                    const TileInfoPOD &ti = bi.tiles_nonrouting[TILE_IO];

-                    // Enable input buffer and disable pull-up resistor in block

-                    // (this is used by the PLL).

-                    set_ie_bit_logical(ctx, ti, config.at(iey).at(iex), "IoCtrl.IE_" + std::to_string(iez), true);

-                    set_ie_bit_logical(ctx, ti, config.at(iey).at(iex), "IoCtrl.REN_" + std::to_string(iez), false);

-                    // PINTYPE[0] passes the PLL through to the fabric.

-                    set_config(ti, config.at(io_beli.y).at(io_beli.x), "IOB_" + std::to_string(io_beli.z) + ".PINTYPE_0", true);

-

-                    found = true;

-                    break;

-                }

+                // Write config.

+                const TileInfoPOD &ti = bi.tiles_nonrouting[TILE_IO];

+                // Enable input buffer and disable pull-up resistor in block

+                // (this is used by the PLL).

+                set_ie_bit_logical(ctx, ti, config.at(iey).at(iex), "IoCtrl.IE_" + std::to_string(iez), true);

+                set_ie_bit_logical(ctx, ti, config.at(iey).at(iex), "IoCtrl.REN_" + std::to_string(iez), false);

+                // PINTYPE[0] passes the PLL through to the fabric.

+                set_config(ti, config.at(io_beli.y).at(io_beli.x), "IOB_" + std::to_string(io_beli.z) + ".PINTYPE_0", true);

 

-                if (!found) {

-                    log_error("Could not find SB_IO forwarding PLL '%s' %s signal\n",

-                            cell.second->name.c_str(ctx), port.second.name.c_str(ctx));

-                }

             }

 

         } else {