/*
    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio

    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.
*/

/**
 * @defgroup IO_BLOCK Abstract I/O Block Device
 * @ingroup HAL_INTERFACES
 *
 * @section io_block_1 Driver State Machine
 * The drivers implementing this interface shall implement the following
 * state machine internally. Not all the driver functionalities can be used
 * in any moment, any transition not explicitly shown in the following
 * diagram has to be considered an error and shall be captured by an
 * assertion (if enabled).
 * @if LATEX_PDF
 * @dot
  digraph example {
    size="5, 7";
    rankdir="LR";

    node [shape=circle, fontname=Sans, fontsize=8, fixedsize="true", width="0.9", height="0.9"];
    edge [fontname=Sans, fontsize=8];

    stop  [label="BLK_STOP\nLow Power"];
    uninit [label="BLK_UNINIT", style="bold"];
    active [label="BLK_ACTIVE\nClock Enabled"];
    connecting [label="BLK_CONN.ING\nConnecting"];
    disconnecting [label="BLK_DISC.ING\nDisconnecting"];
    ready [label="BLK_READY\nCard Ready"];
    reading [label="BLK_READING\nReading"];
    writing [label="BLK_WRITING\nWriting"];

    uninit -> stop [label=" blkInit()", constraint=false];
    stop -> stop [label="\nblkStop()"];
    stop -> active [label="\nblkStart()"];
    active -> stop [label="\nblkStop()"];
    active -> active [label="\nblkStart()\nblkDisconnect()"];
    active -> connecting [label="\nblkConnect()"];
    connecting -> ready [label="\nconnection\nsuccessful"];
    connecting -> ready [label="\nblkConnect()", dir="back"];
    connecting -> active [label="\nconnection\nfailed"];
    disconnecting -> ready [label="\nblkDisconnect()", dir="back"];
    active -> disconnecting [label="\ndisconnection\nfinished", dir="back"];
    ready -> reading [label="\nblkRead()"];
    reading -> ready [label="\nread finished\nread error"];
    ready -> writing [label="\nblkWrite()"];
    writing -> ready [label="\nwrite finished\nwrite error"];
  }
 * @enddot
 * @else
 * @dot
  digraph example {
    rankdir="LR";

    node [shape=circle, fontname=Sans, fontsize=8, fixedsize="true", width="0.9", height="0.9"];
    edge [fontname=Sans, fontsize=8];

    stop  [label="BLK_STOP\nLow Power"];
    uninit [label="BLK_UNINIT", style="bold"];
    active [label="BLK_ACTIVE\nClock Enabled"];
    connecting [label="BLK_CONN.ING\nConnecting"];
    disconnecting [label="BLK_DISC.ING\nDisconnecting"];
    ready [label="BLK_READY\nCard Ready"];
    reading [label="BLK_READING\nReading"];
    writing [label="BLK_WRITING\nWriting"];
    syncing [label="BLK_SYNCING\nSynchronizing"];

    uninit -> stop [label=" blkInit()", constraint=false];
    stop -> stop [label="\nblkStop()"];
    stop -> active [label="\nblkStart()"];
    active -> stop [label="\nblkStop()"];
    active -> active [label="\nblkStart()\nblkDisconnect()"];
    active -> connecting [label="\nblkConnect()"];
    connecting -> ready [label="\nconnection\nsuccessful"];
    connecting -> ready [label="\nblkConnect()", dir="back"];
    connecting -> active [label="\nconnection\nfailed"];
    disconnecting -> ready [label="\nblkDisconnect()", dir="back"];
    active -> disconnecting [label="\ndisconnection\nfinished", dir="back"];
    ready -> reading [label="\nblkRead()"];
    reading -> ready [label="\nread finished\nread error"];
    ready -> writing [label="\nblkWrite()"];
    writing -> ready [label="\nwrite finished\nwrite error"];
    ready -> syncing [label="\nblkSync()"];
    syncing -> ready [label="\nsynchronization finished"];
  }
 * @enddot
 * @endif
 */