hw/ip/spi_host/rtl/spi_host_window.sv

// Copyright lowRISC contributors.
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0
//
// Module to manage TX FIFO window for Serial Peripheral Interface (SPI) host IP.
//

module spi_host_window (
  input  clk_i,
  input  rst_ni,
  input  tlul_pkg::tl_h2d_t rx_win_i,
  output tlul_pkg::tl_d2h_t rx_win_o,
  input  tlul_pkg::tl_h2d_t tx_win_i,
  output tlul_pkg::tl_d2h_t tx_win_o,
  output logic [31:0]       tx_data_o,
  output logic [3:0]        tx_be_o,
  output logic              tx_valid_o,
  input        [31:0]       rx_data_i,
  output logic              rx_ready_o
);

  localparam int AW = spi_host_reg_pkg::BlockAw;
  localparam int DW = 32;
  localparam int ByteMaskW = DW / 8;

  logic         rx_we;

  // Only support reads from the data RX fifo window
  logic  rx_access_error;
  assign rx_access_error = rx_we;

  tlul_adapter_reg #(
    .RegAw (AW),
    .RegDw (DW)
  ) u_adapter_rx (
    .clk_i,
    .rst_ni,
    .tl_i        (rx_win_i),
    .tl_o        (rx_win_o),
    .en_ifetch_i (prim_mubi_pkg::MuBi4False),
    .intg_error_o(),
    .we_o        (rx_we),
    .re_o        (rx_ready_o),
    .addr_o      (),
    .wdata_o     (),
    .be_o        (),
    .rdata_i     (rx_data_i),
    .error_i     (rx_access_error),
    .busy_i      ('0)
  );

  // translate bitmask to byte mask
  logic [DW-1:0] bit_mask;
  for (genvar i = 0; i < ByteMaskW; i++) begin : gen_byte_mask
     assign tx_be_o[i] = |bit_mask[i*8 +: 8];

    // all the bits of particular byte must be the same
    `ASSERT(BitMaskCheck_A, (|bit_mask[i*8 +: 8] == 1'b0) ||
                            (&bit_mask[i*8 +: 8] == 1'b1))
  end

  // Only support writes to the data TX fifo window
  tlul_adapter_sram #(
    .SramAw(AW),
    .SramDw(DW),
    .Outstanding(1),
    .ByteAccess(1),
    .ErrOnWrite(0),
    .ErrOnRead(1)
  ) u_adapter_tx (
    .clk_i,
    .rst_ni,
    .tl_i(tx_win_i),
    .tl_o(tx_win_o),
    .en_ifetch_i(prim_mubi_pkg::MuBi4False),
    .req_o(tx_valid_o),
    .req_type_o(),
    .gnt_i(1'b1),
    .we_o(),
    .addr_o(),
    .wdata_o(tx_data_o),
    .wmask_o(bit_mask),
    .intg_error_o(),
    .rdata_i('0),
    .rvalid_i('0),
    .rerror_i('0)
  );

endmodule : spi_host_window