caravel/verilog/rtl/gpio_signal_buffering.v

487 lines
15 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 ---
*
* This macro buffers long wires between housekeeping and the GPIO control
* blocks at the top level of caravel. 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
* GPIO 14 3.6 2
* GPIO 15 4.5 3
* GPIO 16 4.7 3
* GPIO 17 5.1 3
* GPIO 18 5.4 4 RHS
*-------------------------------------------------------
* GPIO 19 8.4 6 LHS
* GPIO 20 8.2 6
* GPIO 21 7.9 6
* GPIO 22 7.7 5
* GPIO 23 7.4 5
* GPIO 24 6.4 4
* GPIO 25 6.1 4
* 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: 95 (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 (
`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
*/
input [30:0] mgmt_io_in_unbuf;
input [30:0] mgmt_io_out_unbuf;
input [2:0] mgmt_io_oeb_unbuf;
output [2:0] mgmt_io_oeb_buf;
output [30:0] mgmt_io_in_buf;
output [30:0] mgmt_io_out_buf;
/* Instantiate 95 + 95 + 6 = 196 buffers of size 8 */
wire [195:0] buf_in;
wire [195:0] buf_out;
sky130_fd_sc_hd__buf_8 signal_buffers [195:0] (
`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];
assign buf_in[8] = mgmt_io_in_unbuf[7];
assign buf_in[9] = buf_out[8];
assign mgmt_io_in_buf[7] = buf_out[9];
assign buf_in[10] = mgmt_io_in_unbuf[8];
assign buf_in[11] = buf_out[10];
assign buf_in[12] = buf_out[11];
assign mgmt_io_in_buf[8] = buf_out[12];
assign buf_in[13] = mgmt_io_in_unbuf[9];
assign buf_in[14] = buf_out[13];
assign buf_in[15] = buf_out[14];
assign mgmt_io_in_buf[9] = buf_out[15];
assign buf_in[16] = mgmt_io_in_unbuf[10];
assign buf_in[17] = buf_out[16];
assign buf_in[18] = buf_out[17];
assign mgmt_io_in_buf[10] = buf_out[18];
assign buf_in[19] = mgmt_io_in_unbuf[11];
assign buf_in[20] = buf_out[19];
assign buf_in[21] = buf_out[20];
assign buf_in[22] = buf_out[21];
assign mgmt_io_in_buf[11] = buf_out[22];
//----------------------------------------
// mgmt_io_in, left-hand side
//----------------------------------------
assign buf_in[23] = mgmt_io_in_unbuf[12];
assign buf_in[24] = buf_out[23];
assign buf_in[25] = buf_out[24];
assign buf_in[26] = buf_out[25];
assign buf_in[27] = buf_out[26];
assign buf_in[28] = buf_out[27];
assign mgmt_io_in_buf[12] = buf_out[28];
assign buf_in[29] = mgmt_io_in_unbuf[13];
assign buf_in[30] = buf_out[29];
assign buf_in[31] = buf_out[30];
assign buf_in[32] = buf_out[31];
assign buf_in[33] = buf_out[32];
assign buf_in[34] = buf_out[33];
assign mgmt_io_in_buf[13] = buf_out[34];
assign buf_in[35] = mgmt_io_in_unbuf[14];
assign buf_in[36] = buf_out[35];
assign buf_in[37] = buf_out[36];
assign buf_in[38] = buf_out[37];
assign buf_in[39] = buf_out[38];
assign buf_in[40] = buf_out[39];
assign mgmt_io_in_buf[14] = buf_out[40];
assign buf_in[41] = mgmt_io_in_unbuf[15];
assign buf_in[42] = buf_out[41];
assign buf_in[43] = buf_out[42];
assign buf_in[44] = buf_out[43];
assign buf_in[45] = buf_out[44];
assign mgmt_io_in_buf[15] = buf_out[45];
assign buf_in[46] = mgmt_io_in_unbuf[16];
assign buf_in[47] = buf_out[46];
assign buf_in[48] = buf_out[47];
assign buf_in[49] = buf_out[48];
assign buf_in[50] = buf_out[49];
assign mgmt_io_in_buf[16] = buf_out[50];
assign buf_in[51] = mgmt_io_in_unbuf[17];
assign buf_in[52] = buf_out[51];
assign buf_in[53] = buf_out[52];
assign buf_in[54] = buf_out[53];
assign mgmt_io_in_buf[17] = buf_out[54];
assign buf_in[55] = mgmt_io_in_unbuf[18];
assign buf_in[56] = buf_out[55];
assign buf_in[57] = buf_out[56];
assign buf_in[58] = buf_out[57];
assign mgmt_io_in_buf[18] = buf_out[58];
assign buf_in[59] = mgmt_io_in_unbuf[19];
assign buf_in[60] = buf_out[59];
assign buf_in[61] = buf_out[60];
assign buf_in[62] = buf_out[61];
assign mgmt_io_in_buf[19] = buf_out[62];
assign buf_in[63] = mgmt_io_in_unbuf[20];
assign buf_in[64] = buf_out[63];
assign buf_in[65] = buf_out[64];
assign buf_in[66] = buf_out[65];
assign mgmt_io_in_buf[20] = buf_out[66];
assign buf_in[67] = mgmt_io_in_unbuf[21];
assign buf_in[68] = buf_out[67];
assign buf_in[69] = buf_out[68];
assign buf_in[70] = buf_out[69];
assign mgmt_io_in_buf[21] = buf_out[70];
assign buf_in[71] = mgmt_io_in_unbuf[22];
assign buf_in[72] = buf_out[71];
assign buf_in[73] = buf_out[72];
assign buf_in[74] = buf_out[73];
assign mgmt_io_in_buf[22] = buf_out[74];
assign buf_in[75] = mgmt_io_in_unbuf[23];
assign buf_in[76] = buf_out[75];
assign buf_in[77] = buf_out[76];
assign mgmt_io_in_buf[23] = buf_out[77];
assign buf_in[78] = mgmt_io_in_unbuf[24];
assign buf_in[79] = buf_out[78];
assign buf_in[80] = buf_out[79];
assign mgmt_io_in_buf[24] = buf_out[80];
assign buf_in[81] = mgmt_io_in_unbuf[25];
assign buf_in[82] = buf_out[81];
assign buf_in[83] = buf_out[82];
assign mgmt_io_in_buf[25] = buf_out[83];
assign buf_in[84] = mgmt_io_in_unbuf[26];
assign buf_in[85] = buf_out[84];
assign buf_in[86] = buf_out[85];
assign mgmt_io_in_buf[26] = buf_out[86];
assign buf_in[87] = mgmt_io_in_unbuf[27];
assign buf_in[88] = buf_out[87];
assign mgmt_io_in_buf[27] = buf_out[88];
assign buf_in[89] = mgmt_io_in_unbuf[28];
assign buf_in[90] = buf_out[89];
assign mgmt_io_in_buf[28] = buf_out[90];
assign buf_in[91] = mgmt_io_in_unbuf[29];
assign buf_in[92] = buf_out[91];
assign mgmt_io_in_buf[29] = buf_out[92];
assign buf_in[93] = mgmt_io_in_unbuf[30];
assign buf_in[94] = buf_out[93];
assign mgmt_io_in_buf[30] = buf_out[94];
//----------------------------------------
// mgmt_io_out, right-hand side
//----------------------------------------
assign buf_in[95] = mgmt_io_out_unbuf[0];
assign mgmt_io_out_buf[0] = buf_out[95];
assign buf_in[96] = mgmt_io_out_unbuf[1];
assign mgmt_io_out_buf[1] = buf_out[96];
assign buf_in[97] = mgmt_io_out_unbuf[2];
assign mgmt_io_out_buf[2] = buf_out[97];
assign buf_in[98] = mgmt_io_out_unbuf[3];
assign mgmt_io_out_buf[3] = buf_out[98];
assign buf_in[99] = mgmt_io_out_unbuf[4];
assign mgmt_io_out_buf[4] = buf_out[99];
assign buf_in[100] = mgmt_io_out_unbuf[5];
assign mgmt_io_out_buf[5] = buf_out[100];
assign buf_in[101] = mgmt_io_out_unbuf[6];
assign buf_in[102] = buf_out[101];
assign mgmt_io_out_buf[6] = buf_out[102];
assign buf_in[103] = mgmt_io_out_unbuf[7];
assign buf_in[104] = buf_out[103];
assign mgmt_io_out_buf[7] = buf_out[104];
assign buf_in[105] = mgmt_io_out_unbuf[8];
assign buf_in[106] = buf_out[105];
assign buf_in[107] = buf_out[106];
assign mgmt_io_out_buf[8] = buf_out[107];
assign buf_in[108] = mgmt_io_out_unbuf[9];
assign buf_in[109] = buf_out[108];
assign buf_in[110] = buf_out[109];
assign mgmt_io_out_buf[9] = buf_out[110];
assign buf_in[111] = mgmt_io_out_unbuf[10];
assign buf_in[112] = buf_out[111];
assign buf_in[113] = buf_out[112];
assign mgmt_io_out_buf[10] = buf_out[113];
assign buf_in[114] = mgmt_io_out_unbuf[11];
assign buf_in[115] = buf_out[114];
assign buf_in[116] = buf_out[115];
assign buf_in[117] = buf_out[116];
assign mgmt_io_out_buf[11] = buf_out[117];
//----------------------------------------
// mgmt_io_out, left-hand side
//----------------------------------------
assign buf_in[118] = mgmt_io_out_unbuf[12];
assign buf_in[119] = buf_out[118];
assign buf_in[120] = buf_out[119];
assign buf_in[121] = buf_out[120];
assign buf_in[122] = buf_out[121];
assign buf_in[123] = buf_out[122];
assign mgmt_io_out_buf[12] = buf_out[123];
assign buf_in[124] = mgmt_io_out_unbuf[13];
assign buf_in[125] = buf_out[124];
assign buf_in[126] = buf_out[125];
assign buf_in[127] = buf_out[126];
assign buf_in[128] = buf_out[127];
assign buf_in[129] = buf_out[128];
assign mgmt_io_out_buf[13] = buf_out[129];
assign buf_in[130] = mgmt_io_out_unbuf[14];
assign buf_in[131] = buf_out[130];
assign buf_in[132] = buf_out[131];
assign buf_in[133] = buf_out[132];
assign buf_in[134] = buf_out[133];
assign buf_in[135] = buf_out[134];
assign mgmt_io_out_buf[14] = buf_out[135];
assign buf_in[136] = mgmt_io_out_unbuf[15];
assign buf_in[137] = buf_out[136];
assign buf_in[138] = buf_out[137];
assign buf_in[139] = buf_out[138];
assign buf_in[140] = buf_out[139];
assign mgmt_io_out_buf[15] = buf_out[140];
assign buf_in[141] = mgmt_io_out_unbuf[16];
assign buf_in[142] = buf_out[141];
assign buf_in[143] = buf_out[142];
assign buf_in[144] = buf_out[143];
assign buf_in[145] = buf_out[144];
assign mgmt_io_out_buf[16] = buf_out[145];
assign buf_in[146] = mgmt_io_out_unbuf[17];
assign buf_in[147] = buf_out[146];
assign buf_in[148] = buf_out[147];
assign buf_in[149] = buf_out[148];
assign mgmt_io_out_buf[17] = buf_out[149];
assign buf_in[150] = mgmt_io_out_unbuf[18];
assign buf_in[151] = buf_out[150];
assign buf_in[152] = buf_out[151];
assign buf_in[153] = buf_out[152];
assign mgmt_io_out_buf[18] = buf_out[153];
assign buf_in[154] = mgmt_io_out_unbuf[19];
assign buf_in[155] = buf_out[154];
assign buf_in[156] = buf_out[155];
assign buf_in[157] = buf_out[156];
assign mgmt_io_out_buf[19] = buf_out[157];
assign buf_in[158] = mgmt_io_out_unbuf[20];
assign buf_in[159] = buf_out[158];
assign buf_in[160] = buf_out[159];
assign buf_in[161] = buf_out[160];
assign mgmt_io_out_buf[20] = buf_out[161];
assign buf_in[162] = mgmt_io_out_unbuf[21];
assign buf_in[163] = buf_out[162];
assign buf_in[164] = buf_out[163];
assign buf_in[165] = buf_out[164];
assign mgmt_io_out_buf[21] = buf_out[165];
assign buf_in[166] = mgmt_io_out_unbuf[22];
assign buf_in[167] = buf_out[166];
assign buf_in[168] = buf_out[167];
assign buf_in[169] = buf_out[168];
assign mgmt_io_out_buf[22] = buf_out[169];
assign buf_in[170] = mgmt_io_out_unbuf[23];
assign buf_in[171] = buf_out[170];
assign buf_in[172] = buf_out[171];
assign mgmt_io_out_buf[23] = buf_out[172];
assign buf_in[173] = mgmt_io_out_unbuf[24];
assign buf_in[174] = buf_out[173];
assign buf_in[175] = buf_out[174];
assign mgmt_io_out_buf[24] = buf_out[175];
assign buf_in[176] = mgmt_io_out_unbuf[25];
assign buf_in[177] = buf_out[176];
assign buf_in[178] = buf_out[177];
assign mgmt_io_out_buf[25] = buf_out[178];
assign buf_in[179] = mgmt_io_out_unbuf[26];
assign buf_in[180] = buf_out[179];
assign buf_in[181] = buf_out[180];
assign mgmt_io_out_buf[26] = buf_out[181];
assign buf_in[182] = mgmt_io_out_unbuf[27];
assign buf_in[183] = buf_out[182];
assign mgmt_io_out_buf[27] = buf_out[183];
assign buf_in[184] = mgmt_io_out_unbuf[28];
assign buf_in[185] = buf_out[184];
assign mgmt_io_out_buf[28] = buf_out[185];
assign buf_in[186] = mgmt_io_out_unbuf[29];
assign buf_in[187] = buf_out[186];
assign mgmt_io_out_buf[29] = buf_out[187];
assign buf_in[188] = mgmt_io_out_unbuf[30];
assign buf_in[189] = buf_out[188];
assign mgmt_io_out_buf[30] = buf_out[189];
//----------------------------------------
// mgmt_io_oeb, left-hand side (only)
//----------------------------------------
assign buf_in[190] = mgmt_io_oeb_unbuf[0];
assign buf_in[191] = buf_out[190];
assign mgmt_io_oeb_buf[0] = buf_out[191];
assign buf_in[192] = mgmt_io_oeb_unbuf[1];
assign buf_in[193] = buf_out[192];
assign mgmt_io_oeb_buf[1] = buf_out[193];
assign buf_in[194] = mgmt_io_oeb_unbuf[2];
assign buf_in[195] = buf_out[194];
assign mgmt_io_oeb_buf[2] = buf_out[195];
sky130_ef_sc_hd__decap_12 sigbuf_decaps [100:0] (
`ifdef USE_POWER_PINS
.VPWR(vccd),
.VGND(vssd),
.VPB(vccd),
.VNB(vssd)
`endif
);
endmodule