verilog/rtl/mgmt_protect.v

// Copyright 2020 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.

`default_nettype none
/*----------------------------------------------------------------------*/
/* Buffers protecting the management region from the user region.	*/
/* This mainly consists of tristate buffers that are enabled by a	*/
/* "logic 1" output connected to the user's VCCD domain.  This ensures	*/
/* that the buffer is disabled and the output high-impedence when the	*/
/* user 1.8V supply is absent.						*/
/*----------------------------------------------------------------------*/
/* Because there is no tristate buffer with a non-inverted enable, a	*/
/* tristate inverter with non-inverted enable is used in series with	*/
/* another (normal) inverter.						*/
/*----------------------------------------------------------------------*/
/* For the sake of placement/routing, one conb (logic 1) cell is used	*/
/* for every buffer.							*/
/*----------------------------------------------------------------------*/

module mgmt_protect (
`ifdef USE_POWER_PINS
    inout	  vccd,
    inout	  vssd,
    inout	  vccd1,
    inout	  vssd1,
    inout	  vccd2,
    inout	  vssd2,
    inout	  vdda1,
    inout	  vssa1,
    inout	  vdda2,
    inout	  vssa2,
`endif

    input 	  caravel_clk,
    input 	  caravel_clk2,
    input	  caravel_rstn,
    input 	  mprj_cyc_o_core,
    input 	  mprj_stb_o_core,
    input         mprj_we_o_core,
    input [3:0]   mprj_sel_o_core,
    input [31:0]  mprj_adr_o_core,
    input [31:0]  mprj_dat_o_core,

    // All signal in/out directions are the reverse of the signal
    // names at the buffer intrface.

    output [127:0] la_data_in_mprj,
    input  [127:0] la_data_out_mprj,
    input  [127:0] la_oen_mprj,

    input  [127:0] la_data_out_core,
    output [127:0] la_data_in_core,
    output [127:0] la_oen_core,

    output 	  user_clock,
    output 	  user_clock2,
    output 	  user_resetn,
    output 	  user_reset,
    output 	  mprj_cyc_o_user,
    output 	  mprj_stb_o_user,
    output 	  mprj_we_o_user,
    output [3:0]  mprj_sel_o_user,
    output [31:0] mprj_adr_o_user,
    output [31:0] mprj_dat_o_user,
    output	  user1_vcc_powergood,
    output	  user2_vcc_powergood,
    output	  user1_vdd_powergood,
    output	  user2_vdd_powergood
);

	wire [458:0] mprj_logic1;
	wire	     mprj2_logic1;

	wire mprj_vdd_logic1_h;
	wire mprj2_vdd_logic1_h;
	wire mprj_vdd_logic1;
	wire mprj2_vdd_logic1;

	wire user1_vcc_powergood;
	wire user2_vcc_powergood;
	wire user1_vdd_powergood;
	wire user2_vdd_powergood;

	wire [127:0] la_data_in_mprj_bar;

        sky130_fd_sc_hd__conb_1 mprj_logic_high [458:0] (
`ifdef USE_POWER_PINS
                .VPWR(vccd1),
                .VGND(vssd1),
                .VPB(vccd1),
                .VNB(vssd1),
`endif
                .HI(mprj_logic1),
                .LO()
        );

        sky130_fd_sc_hd__conb_1 mprj2_logic_high (
`ifdef USE_POWER_PINS
                .VPWR(vccd2),
                .VGND(vssd2),
                .VPB(vccd2),
                .VNB(vssd2),
`endif
                .HI(mprj2_logic1),
                .LO()
        );

	// Logic high in the VDDA (3.3V) domains

	mgmt_protect_hv powergood_check (
`ifdef USE_POWER_PINS
	    .vccd(vccd),
	    .vssd(vssd),
	    .vdda1(vdda1),
	    .vssa1(vssa1),
	    .vdda2(vdda2),
	    .vssa2(vssa2),
`endif
	    .mprj_vdd_logic1(mprj_vdd_logic1),
	    .mprj2_vdd_logic1(mprj2_vdd_logic1)
	);


	// Buffering from the user side to the management side.
	// NOTE:  This is intended to be better protected, by a full
	// chain of an lv-to-hv buffer followed by an hv-to-lv buffer.
	// This serves as a placeholder until that configuration is
	// checked and characterized.  The function below forces the
	// data input to the management core to be a solid logic 0 when
	// the user project is powered down.

	sky130_fd_sc_hd__nand2_4 user_to_mprj_in_gates [127:0] (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
		.Y(la_data_in_mprj_bar),
		.A(la_data_out_core),
		.B(mprj_logic1[457:330])
	);

	sky130_fd_sc_hd__inv_8 user_to_mprj_in_buffers [127:0] (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
		.Y(la_data_in_mprj),
		.A(la_data_in_mprj_bar)
	);

	// The remaining circuitry guards against the management
	// SoC dumping current into the user project area when
	// the user project area is powered down.
	
        sky130_fd_sc_hd__einvp_8 mprj_rstn_buf (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(user_resetn),
                .A(~caravel_rstn),
                .TE(mprj_logic1[0])
        );

        assign user_reset = ~user_resetn;

        sky130_fd_sc_hd__einvp_8 mprj_clk_buf (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(user_clock),
                .A(~caravel_clk),
                .TE(mprj_logic1[1])
        );

        sky130_fd_sc_hd__einvp_8 mprj_clk2_buf (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(user_clock2),
                .A(~caravel_clk2),
                .TE(mprj_logic1[2])
        );

        sky130_fd_sc_hd__einvp_8 mprj_cyc_buf (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(mprj_cyc_o_user),
                .A(~mprj_cyc_o_core),
                .TE(mprj_logic1[3])
        );

        sky130_fd_sc_hd__einvp_8 mprj_stb_buf (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(mprj_stb_o_user),
                .A(~mprj_stb_o_core),
                .TE(mprj_logic1[4])
        );

        sky130_fd_sc_hd__einvp_8 mprj_we_buf (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(mprj_we_o_user),
                .A(~mprj_we_o_core),
                .TE(mprj_logic1[5])
        );

        sky130_fd_sc_hd__einvp_8 mprj_sel_buf [3:0] (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(mprj_sel_o_user),
                .A(~mprj_sel_o_core),
                .TE(mprj_logic1[9:6])
        );

        sky130_fd_sc_hd__einvp_8 mprj_adr_buf [31:0] (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(mprj_adr_o_user),
                .A(~mprj_adr_o_core),
                .TE(mprj_logic1[41:10])
        );

        sky130_fd_sc_hd__einvp_8 mprj_dat_buf [31:0] (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(mprj_dat_o_user),
                .A(~mprj_dat_o_core),
                .TE(mprj_logic1[73:42])
        );

	/* Project data out from the managment side to the user project	*/
	/* area when the user project is powered down.			*/

        sky130_fd_sc_hd__einvp_8 la_buf [127:0] (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .Z(la_data_in_core),
                .A(~la_data_out_mprj),
                .TE(mprj_logic1[201:74])
        );

	/* Project data out enable (bar) from the managment side to the	*/
	/* user project	area when the user project is powered down.	*/

	sky130_fd_sc_hd__einvp_8 user_to_mprj_oen_buffers [127:0] (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
		.Z(la_oen_core),
		.A(~la_oen_mprj),
                .TE(mprj_logic1[329:202])
	);

	/* The conb cell output is a resistive connection directly to	*/
	/* the power supply, so when returning the user1_powergood	*/
	/* signal, make sure that it is buffered properly.		*/

        sky130_fd_sc_hd__buf_8 mprj_pwrgood (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .A(mprj_logic1[458]),
                .X(user1_vcc_powergood)
	);

        sky130_fd_sc_hd__buf_8 mprj2_pwrgood (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .A(mprj2_vdd_logic1),
                .X(user2_vcc_powergood)
	);

        sky130_fd_sc_hd__buf_8 mprj_vdd_pwrgood (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .A(mprj_vdd_logic1),
                .X(user1_vdd_powergood)
	);

        sky130_fd_sc_hd__buf_8 mprj2_vdd_pwrgood (
`ifdef USE_POWER_PINS
                .VPWR(vccd),
                .VGND(vssd),
                .VPB(vccd),
                .VNB(vssd),
`endif
                .A(mprj2_vdd_logic1),
                .X(user2_vdd_powergood)
	);
endmodule
`default_nettype wire