hw/dv/sv/spi_agent/spi_device_driver.sv

// Copyright lowRISC contributors.
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0

class spi_device_driver extends spi_driver;
  `uvm_component_utils(spi_device_driver)
  `uvm_component_new

  virtual task reset_signals();
    forever begin
      @(negedge cfg.vif.rst_n);
      `uvm_info(`gfn, "\n  dev_drv: in reset progress", UVM_DEBUG)
      under_reset = 1'b1;
      @(posedge cfg.vif.rst_n);
      under_reset = 1'b0;
      `uvm_info(`gfn, "\n  dev_drv: out of reset", UVM_DEBUG)
    end
  endtask

  virtual task get_and_drive();
    spi_item req, rsp;

    forever begin
      seq_item_port.get_next_item(req);
      wait (!under_reset && !cfg.vif.csb[cfg.csid]);
      fork
        begin: iso_fork
          fork
            send_rx_item(req);
            drive_bus_to_highz();
            drive_bus_for_reset();
          join_any
          disable fork;
        end: iso_fork
      join
      seq_item_port.item_done();
      `uvm_info(`gfn, "\n  dev_drv: item done", UVM_HIGH)
    end
  endtask : get_and_drive


  virtual task send_rx_item(spi_item item);
    logic [3:0] sio_bits;
    bit         bits_q[$];
    int         max_tx_bits;

    if (cfg.byte_order) cfg.swap_byte_order(item.data);
    bits_q = {>> 1 {item.data}};
    max_tx_bits = cfg.get_sio_size();

    `uvm_info(`gfn, $sformatf("\n  dev_drv: send_rx_item, return %0d bits to dut",
                              bits_q.size()), UVM_DEBUG)
    // pop enough bits do drive all needed sio
    while (bits_q.size() > 0) begin
       if (bits_q.size() > 0) cfg.wait_sck_edge(DrivingEdge);
      for (int i = 0; i < 4; i++) begin
        sio_bits[i] = (i < max_tx_bits) ? bits_q.pop_front() : 1'bz;
      end
      send_data_to_sio(cfg.spi_mode, sio_bits);
      `uvm_info(`gfn, $sformatf("\n  dev_drv: assert data bit[%0d] %b",
                                bits_q.size(), sio_bits[0]), UVM_DEBUG)

    end
  endtask : send_rx_item

  virtual task send_data_to_sio(spi_mode_e mode, input logic [3:0] sio_bits);
    unique case (mode)
      Standard: cfg.vif.sio[1]   <= sio_bits[0];
      Dual:     cfg.vif.sio[1:0] <= sio_bits[1:0];
      default:  cfg.vif.sio      <= sio_bits;
    endcase
  endtask : send_data_to_sio

  virtual task drive_bus_to_highz();
    @(posedge cfg.vif.csb[cfg.csid]);
    case (cfg.spi_mode)
      Standard: cfg.vif.sio[1]   = 1'bz;
      Dual:     cfg.vif.sio[1:0] = 2'bzz;
      default:  cfg.vif.sio      = 4'bzzzz;   // including Quad SPI mode
    endcase
    `uvm_info(`gfn, "\n  dev_drv: drive_bus_to_highz is done", UVM_DEBUG)
  endtask : drive_bus_to_highz

  virtual task drive_bus_for_reset();
    @(negedge cfg.vif.rst_n);
    cfg.vif.sio = 4'bzzzz;
    `uvm_info(`gfn, "\n  dev_drv: drive_bus_for_reset is done", UVM_DEBUG)
  endtask : drive_bus_for_reset
endclass : spi_device_driver