-- Raspberry Pi LPC1114 I/O Processor SPI Agent Firmware Transport Services
-- using HID Remote I/O using libhidapi

-- Copyright (C)2019, Philip Munts, President, Munts AM Corp.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are met:
--
-- * Redistributions of source code must retain the above copyright notice,
--   this list of conditions and the following disclaimer.
--
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-- ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-- POSSIBILITY OF SUCH DAMAGE.

WITH Interfaces;

WITH errno;
WITH HID.hidapi;
WITH Message64;
WITH RemoteIO.Client;

USE TYPE RemoteIO.Client.Device;

PACKAGE BODY spi_agent.transport IS

  dev : RemoteIO.Client.Device := NULL;

  -- Initialize the SPI Agent Firmware transport library

  PROCEDURE open(servername : String; error : OUT Integer) IS

  BEGIN
    IF dev /= NULL THEN
      error := errno.EBUSY;
      RETURN;
    END IF;

    -- TODO: Interpret the servername parameter as a USB device serial number
    dev   := RemoteIO.Client.Create(HID.hidapi.Create);
    error := errno.EOK;

  EXCEPTION
    WHEN OTHERS =>
      error := errno.EIO;
  END open;

  -- Deinitialize the SPI Agent Firmware transport library

  PROCEDURE close(error : OUT Integer) IS

  BEGIN
    IF dev = NULL THEN
      error := errno.EINVAL;
      RETURN;
    END IF;

    -- TODO: Destroy the existing Remote I/O device object
    dev   := NULL;
    error := errno.EOK;
  END close;

  -- Dispatch an SPI Agent Firmware command to the transport library

  PROCEDURE command
   (command  : IN spi_agent.messages.SPIAGENT_COMMAND_MSG_t;
    response : OUT spi_agent.messages.SPIAGENT_RESPONSE_MSG_t;
    error    : OUT Integer) IS

    cmd  : Message64.Message;
    resp : Message64.Message;

  BEGIN
    IF dev = NULL THEN
      error := errno.EINVAL;
      RETURN;
    END IF;

    cmd     := (OTHERS => 0);
    cmd(0)  := Message64.Byte(RemoteIO.MessageTypes'Pos(
      RemoteIO.DEVICE_OPERATION_REQUEST));

    -- Convert from SPIAGENT_COMMAND_MSG_t to byte stream

    cmd(3)  := Message64.Byte(command.Command/16777216);
    cmd(4)  := Message64.Byte(command.Command/65536 MOD 256);
    cmd(5)  := Message64.Byte(command.Command/256 MOD 256);
    cmd(6)  := Message64.Byte(command.Command MOD 256);

    cmd(7)  := Message64.Byte(command.Pin/16777216);
    cmd(8)  := Message64.Byte(command.Pin/65536 MOD 256);
    cmd(9)  := Message64.Byte(command.Pin/256 MOD 256);
    cmd(10) := Message64.Byte(command.Pin MOD 256);

    cmd(11) := Message64.Byte(command.Data/16777216);
    cmd(12) := Message64.Byte(command.Data/65536 MOD 256);
    cmd(13) := Message64.Byte(command.Data/256 MOD 256);
    cmd(14) := Message64.Byte(command.Data MOD 256);

    -- Execute the command

    dev.Transaction(cmd, resp);

    -- Convert from byte stream to SPIAGENT_RESPONSE_MSG_t

    response.Command :=
      Interfaces.Unsigned_32(resp(3))*16777216  OR
      Interfaces.Unsigned_32(resp(4))*65536     OR
      Interfaces.Unsigned_32(resp(5))*256       OR
      Interfaces.Unsigned_32(resp(6));

    response.Pin :=
      Interfaces.Unsigned_32(resp(7))*16777216  OR
      Interfaces.Unsigned_32(resp(8))*65536     OR
      Interfaces.Unsigned_32(resp(9))*256       OR
      Interfaces.Unsigned_32(resp(10));

    response.Data :=
      Interfaces.Unsigned_32(resp(11))*16777216 OR
      Interfaces.Unsigned_32(resp(12))*65536    OR
      Interfaces.Unsigned_32(resp(13))*256      OR
      Interfaces.Unsigned_32(resp(14));

    response.Error :=
      Interfaces.Unsigned_32(resp(15))*16777216 OR
      Interfaces.Unsigned_32(resp(16))*65536    OR
      Interfaces.Unsigned_32(resp(17))*256      OR
      Interfaces.Unsigned_32(resp(18));

    error := errno.EOK;

  EXCEPTION
    WHEN OTHERS =>
      error := errno.EIO;
  END command;

END spi_agent.transport;