caravel/verilog/rtl/gpio_signal_buffering_alt.v

331 lines
10 KiB
Verilog

// SPDX-FileCopyrightText: 2022 Efabless Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// SPDX-License-Identifier: Apache-2.0
/*
* gpio_signal_buffering_alt ---
*
* This macro buffers long wires between housekeeping and the GPIO control
* blocks at the top level of caravan. The rule of thumb is to limit any
* single wire length to approximately 1.3mm. The physical (manhattan)
* distances and required buffering are as follows:
*
* Breakpoints: 1.3, 2.6, 3.9, 5.2, 6.5, 7.8 (mm)
* # buffers: 1, 2, 3, 4, 5, 6
*
* GPIO # wire length (mm) # buffers
*------------------------------------------------------
* GPIO 0 0.4 0
* GPIO 1 0.2 0
* GPIO 2 0.0 0
* GPIO 3 0.3 0
* GPIO 4 0.5 0
* GPIO 5 0.7 0
* GPIO 6 1.0 0
* GPIO 7 1.4 1
* GPIO 8 1.6 1
* GPIO 9 1.8 1
* GPIO 10 2.1 1
* GPIO 11 2.3 1
* GPIO 12 2.5 1
* GPIO 13 2.7 2 RHS
*-------------------------------------------------------
* GPIO 25 6.1 4 LHS
* GPIO 26 5.9 4
* GPIO 27 5.7 4
* GPIO 28 5.5 4
* GPIO 29 5.3 4
* GPIO 30 5.1 3
* GPIO 31 4.8 3
* GPIO 32 4.2 3
* GPIO 33 4.0 3
* GPIO 34 3.8 2
* GPIO 35 3.5 2
* GPIO 36 3.3 2
* GPIO 37 3.4 2
*------------------------------------------------------
* total number of buffers: 48 (x2 for input and output)
*
* OEB lines go to GPIO 0 and 1 (no buffers needed) and GPIO 35-37
* (2 buffers needed), so OEB lines need 6 additional buffers.
*
* The assumption is that all GPIOs on the left-hand side of the chip are
* routed by taking wires left from the housekeeping across the top of the
* SoC to the left side, and then up to the destination. Right-hand side
* connections go directly up the right side from the housekeeping block.
*
* Note that signal names are related to the signal being passed through;
* "in" and "out" refer to the direction of the signal relative to the
* housekeeping block in the top level. For this macro, unbuffered signals
* "unbuf" are the inputs, and buffered signals "buf" are the outputs.
*/
module gpio_signal_buffering_alt (
`ifdef USE_POWER_PINS
vccd,
vssd,
`endif
mgmt_io_in_unbuf,
mgmt_io_out_unbuf,
mgmt_io_oeb_buf,
mgmt_io_in_buf,
mgmt_io_out_buf,
mgmt_io_oeb_unbuf
);
`ifdef USE_POWER_PINS
input vccd;
input vssd;
`endif
/* NOTE: To match the indices of the same signals in the
* top level, add 35 to all OEB lines and add 7 to all in
* and out lines up to 14, and add 18 to all in and out
* lines above that.
*/
input [19:0] mgmt_io_in_unbuf;
input [19:0] mgmt_io_out_unbuf;
input [2:0] mgmt_io_oeb_unbuf;
output [2:0] mgmt_io_oeb_buf;
output [19:0] mgmt_io_in_buf;
output [19:0] mgmt_io_out_buf;
/* Instantiate 48 + 48 + 6 = 101 buffers of size 8 */
wire [101:0] buf_in;
wire [101:0] buf_out;
sky130_fd_sc_hd__buf_8 signal_buffers [101:0] (
`ifdef USE_POWER_PINS
.VPWR(vccd),
.VGND(vssd),
.VPB(vccd),
.VNB(vssd),
`endif
.A(buf_in),
.X(buf_out)
);
/* Now chain them all together */
//----------------------------------------
// mgmt_io_in, right-hand side
//----------------------------------------
assign buf_in[0] = mgmt_io_in_unbuf[0];
assign mgmt_io_in_buf[0] = buf_out[0];
assign buf_in[1] = mgmt_io_in_unbuf[1];
assign mgmt_io_in_buf[1] = buf_out[1];
assign buf_in[2] = mgmt_io_in_unbuf[2];
assign mgmt_io_in_buf[2] = buf_out[2];
assign buf_in[3] = mgmt_io_in_unbuf[3];
assign mgmt_io_in_buf[3] = buf_out[3];
assign buf_in[4] = mgmt_io_in_unbuf[4];
assign mgmt_io_in_buf[4] = buf_out[4];
assign buf_in[5] = mgmt_io_in_unbuf[5];
assign mgmt_io_in_buf[5] = buf_out[5];
assign buf_in[6] = mgmt_io_in_unbuf[6];
assign buf_in[7] = buf_out[6];
assign mgmt_io_in_buf[6] = buf_out[7];
//----------------------------------------
// mgmt_io_in, left-hand side
//----------------------------------------
assign buf_in[8] = mgmt_io_in_unbuf[7];
assign buf_in[9] = buf_out[8];
assign buf_in[10] = buf_out[9];
assign buf_in[11] = buf_out[10];
assign mgmt_io_in_buf[7] = buf_out[11];
assign buf_in[12] = mgmt_io_in_unbuf[8];
assign buf_in[13] = buf_out[12];
assign buf_in[14] = buf_out[13];
assign buf_in[15] = buf_out[14];
assign mgmt_io_in_buf[8] = buf_out[15];
assign buf_in[16] = mgmt_io_in_unbuf[9];
assign buf_in[17] = buf_out[16];
assign buf_in[18] = buf_out[17];
assign buf_in[19] = buf_out[18];
assign mgmt_io_in_buf[9] = buf_out[19];
assign buf_in[20] = mgmt_io_in_unbuf[10];
assign buf_in[21] = buf_out[20];
assign buf_in[22] = buf_out[21];
assign buf_in[23] = buf_out[22];
assign mgmt_io_in_buf[10] = buf_out[23];
assign buf_in[24] = mgmt_io_in_unbuf[11];
assign buf_in[25] = buf_out[24];
assign buf_in[26] = buf_out[25];
assign buf_in[27] = buf_out[26];
assign mgmt_io_in_buf[11] = buf_out[27];
assign buf_in[28] = mgmt_io_in_unbuf[12];
assign buf_in[29] = buf_out[28];
assign buf_in[30] = buf_out[29];
assign mgmt_io_in_buf[12] = buf_out[30];
assign buf_in[31] = mgmt_io_in_unbuf[13];
assign buf_in[32] = buf_out[31];
assign buf_in[33] = buf_out[32];
assign mgmt_io_in_buf[13] = buf_out[33];
assign buf_in[34] = mgmt_io_in_unbuf[14];
assign buf_in[35] = buf_out[34];
assign buf_in[36] = buf_out[35];
assign mgmt_io_in_buf[14] = buf_out[36];
assign buf_in[37] = mgmt_io_in_unbuf[15];
assign buf_in[38] = buf_out[37];
assign buf_in[39] = buf_out[38];
assign mgmt_io_in_buf[15] = buf_out[39];
assign buf_in[40] = mgmt_io_in_unbuf[16];
assign buf_in[41] = buf_out[40];
assign mgmt_io_in_buf[16] = buf_out[41];
assign buf_in[42] = mgmt_io_in_unbuf[17];
assign buf_in[43] = buf_out[42];
assign mgmt_io_in_buf[17] = buf_out[43];
assign buf_in[44] = mgmt_io_in_unbuf[18];
assign buf_in[45] = buf_out[44];
assign mgmt_io_in_buf[18] = buf_out[45];
assign buf_in[46] = mgmt_io_in_unbuf[19];
assign buf_in[47] = buf_out[46];
assign mgmt_io_in_buf[19] = buf_out[47];
//----------------------------------------
// mgmt_io_out, right-hand side
//----------------------------------------
assign buf_in[48] = mgmt_io_out_unbuf[0];
assign mgmt_io_out_buf[0] = buf_out[48];
assign buf_in[49] = mgmt_io_out_unbuf[1];
assign mgmt_io_out_buf[1] = buf_out[49];
assign buf_in[50] = mgmt_io_out_unbuf[2];
assign mgmt_io_out_buf[2] = buf_out[50];
assign buf_in[51] = mgmt_io_out_unbuf[3];
assign mgmt_io_out_buf[3] = buf_out[51];
assign buf_in[52] = mgmt_io_out_unbuf[4];
assign mgmt_io_out_buf[4] = buf_out[52];
assign buf_in[53] = mgmt_io_out_unbuf[5];
assign mgmt_io_out_buf[5] = buf_out[53];
assign buf_in[54] = mgmt_io_out_unbuf[6];
assign buf_in[55] = buf_out[54];
assign mgmt_io_out_buf[6] = buf_out[55];
//----------------------------------------
// mgmt_io_out, left-hand side
//----------------------------------------
assign buf_in[56] = mgmt_io_out_unbuf[7];
assign buf_in[57] = buf_out[56];
assign buf_in[58] = buf_out[57];
assign buf_in[59] = buf_out[58];
assign mgmt_io_out_buf[7] = buf_out[59];
assign buf_in[60] = mgmt_io_out_unbuf[8];
assign buf_in[61] = buf_out[60];
assign buf_in[62] = buf_out[61];
assign buf_in[63] = buf_out[62];
assign mgmt_io_out_buf[8] = buf_out[63];
assign buf_in[64] = mgmt_io_out_unbuf[9];
assign buf_in[65] = buf_out[64];
assign buf_in[66] = buf_out[65];
assign buf_in[67] = buf_out[66];
assign mgmt_io_out_buf[9] = buf_out[67];
assign buf_in[68] = mgmt_io_out_unbuf[10];
assign buf_in[69] = buf_out[68];
assign buf_in[70] = buf_out[69];
assign buf_in[71] = buf_out[70];
assign mgmt_io_out_buf[10] = buf_out[71];
assign buf_in[72] = mgmt_io_out_unbuf[11];
assign buf_in[73] = buf_out[72];
assign buf_in[74] = buf_out[73];
assign buf_in[75] = buf_out[74];
assign mgmt_io_out_buf[11] = buf_out[75];
assign buf_in[76] = mgmt_io_out_unbuf[12];
assign buf_in[77] = buf_out[76];
assign buf_in[78] = buf_out[77];
assign mgmt_io_out_buf[12] = buf_out[78];
assign buf_in[79] = mgmt_io_out_unbuf[13];
assign buf_in[80] = buf_out[79];
assign buf_in[81] = buf_out[80];
assign mgmt_io_out_buf[13] = buf_out[81];
assign buf_in[82] = mgmt_io_out_unbuf[14];
assign buf_in[83] = buf_out[82];
assign buf_in[84] = buf_out[83];
assign mgmt_io_out_buf[14] = buf_out[84];
assign buf_in[85] = mgmt_io_out_unbuf[15];
assign buf_in[86] = buf_out[85];
assign buf_in[87] = buf_out[86];
assign mgmt_io_out_buf[15] = buf_out[87];
assign buf_in[88] = mgmt_io_out_unbuf[16];
assign buf_in[89] = buf_out[88];
assign mgmt_io_out_buf[16] = buf_out[89];
assign buf_in[90] = mgmt_io_out_unbuf[17];
assign buf_in[91] = buf_out[90];
assign mgmt_io_out_buf[17] = buf_out[91];
assign buf_in[92] = mgmt_io_out_unbuf[18];
assign buf_in[93] = buf_out[92];
assign mgmt_io_out_buf[18] = buf_out[93];
assign buf_in[94] = mgmt_io_out_unbuf[19];
assign buf_in[95] = buf_out[94];
assign mgmt_io_out_buf[19] = buf_out[95];
//----------------------------------------
// mgmt_io_oeb, left-hand side (only)
//----------------------------------------
assign buf_in[96] = mgmt_io_oeb_unbuf[0];
assign buf_in[97] = buf_out[96];
assign mgmt_io_oeb_buf[0] = buf_out[97];
assign buf_in[98] = mgmt_io_oeb_unbuf[1];
assign buf_in[99] = buf_out[98];
assign mgmt_io_oeb_buf[1] = buf_out[99];
assign buf_in[100] = mgmt_io_oeb_unbuf[2];
assign buf_in[101] = buf_out[100];
assign mgmt_io_oeb_buf[2] = buf_out[101];
endmodule