/*
   * HP Human Interface Loop Master Link Controller driver.
   *
   * Copyright (c) 2001 Brian S. Julin
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions, and the following disclaimer,
   *    without modification.
   * 2. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * Alternatively, this software may be distributed under the terms of the
   * GNU General Public License ("GPL").
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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
   *
   * References:
   * HP-HIL Technical Reference Manual.  Hewlett Packard Product No. 45918A
   *
   */
  
  #include <linux/hil.h>
  #include <linux/time.h>
  #include <linux/interrupt.h>
  #include <linux/semaphore.h>
  #include <linux/serio.h>
  #include <linux/list.h>
  
  typedef struct hil_mlc hil_mlc;
  
  /* The HIL has a complicated state engine.
   * We define the structure of nodes in the state engine here.
   */
  enum hilse_act {
    	/* HILSE_OUT prepares to receive input if the next node
  	 * is an IN or EXPECT, and then sends the given packet.
  	 */
  	HILSE_OUT = 0,
  
    	/* HILSE_CTS checks if the loop is busy. */
  	HILSE_CTS,
  
  	/* HILSE_OUT_LAST sends the given command packet to 
  	 * the last configured/running device on the loop.
  	 */
  	HILSE_OUT_LAST,
  
  	/* HILSE_OUT_DISC sends the given command packet to
  	 * the next device past the last configured/running one.
  	 */
  	HILSE_OUT_DISC,
  
  	/* HILSE_FUNC runs a callback function with given arguments.
  	 * a positive return value causes the "ugly" branch to be taken.
  	 */
  	HILSE_FUNC,
  
    	/* HILSE_IN simply expects any non-errored packet to arrive 
  	 * within arg usecs.
  	 */
  	HILSE_IN		= 0x100,
  
    	/* HILSE_EXPECT expects a particular packet to arrive 
  	 * within arg usecs, any other packet is considered an error.
  	 */
  	HILSE_EXPECT,
  
    	/* HILSE_EXPECT_LAST as above but dev field should be last 
  	 * discovered/operational device.
  	 */
  	HILSE_EXPECT_LAST,
  
    	/* HILSE_EXPECT_LAST as above but dev field should be first 
  	 * undiscovered/inoperational device.
  	 */
  	HILSE_EXPECT_DISC
  };
  
  typedef int	(hilse_func) (hil_mlc *mlc, int arg);
  struct hilse_node {
  	enum hilse_act		act;	/* How to process this node         */
  	union {
  		hilse_func	*func;	/* Function to call if HILSE_FUNC   */
  		hil_packet	packet;	/* Packet to send or to compare     */
  	} object;
  	int			arg;	/* Timeout in usec or parm for func */
  	int			good;	/* Node to jump to on success       */
  	int			bad;	/* Node to jump to on error         */
  	int			ugly;	/* Node to jump to on timeout       */
  };
  
  /* Methods for back-end drivers, e.g. hp_sdc_mlc */
  typedef int	(hil_mlc_cts) (hil_mlc *mlc);
  typedef void	(hil_mlc_out) (hil_mlc *mlc);
  typedef int	(hil_mlc_in)  (hil_mlc *mlc, suseconds_t timeout);
  
  struct hil_mlc_devinfo {
  	uint8_t	idd[16];	/* Device ID Byte and Describe Record */
  	uint8_t	rsc[16];	/* Security Code Header and Record */
  	uint8_t	exd[16];	/* Extended Describe Record */
  	uint8_t	rnm[16];	/* Device name as returned by RNM command */
  };
  
  struct hil_mlc_serio_map {
  	hil_mlc *mlc;
  	int di_revmap;
  	int didx;
  };
  
  /* How many (possibly old/detached) devices the we try to keep track of */
  #define HIL_MLC_DEVMEM 16
  
  struct hil_mlc {
  	struct list_head	list;	/* hil_mlc is organized as linked list */
  
  	rwlock_t		lock;
  
  	void *priv; /* Data specific to a particular type of MLC */
  
  	int 			seidx;	/* Current node in state engine */
  	int			istarted, ostarted;
  
  	hil_mlc_cts		*cts;
  	struct semaphore	csem;   /* Raised when loop idle */
  
  	hil_mlc_out		*out;
  	struct semaphore	osem;   /* Raised when outpacket dispatched */
  	hil_packet		opacket;
  
  	hil_mlc_in		*in;
  	struct semaphore	isem;   /* Raised when a packet arrives */
  	hil_packet		ipacket[16];
  	hil_packet		imatch;
  	int			icount;
  	struct timeval		instart;
  	suseconds_t		intimeout;
  
  	int			ddi;	/* Last operational device id */
  	int			lcv;	/* LCV to throttle loops */
  	struct timeval		lcv_tv; /* Time loop was started */
  
  	int			di_map[7]; /* Maps below items to live devs */
  	struct hil_mlc_devinfo	di[HIL_MLC_DEVMEM];
  	struct serio		*serio[HIL_MLC_DEVMEM];
  	struct hil_mlc_serio_map serio_map[HIL_MLC_DEVMEM];
  	hil_packet		serio_opacket[HIL_MLC_DEVMEM];
  	int			serio_oidx[HIL_MLC_DEVMEM];
  	struct hil_mlc_devinfo	di_scratch; /* Temporary area */
  
  	int			opercnt;
  
  	struct tasklet_struct	*tasklet;
  };
  
  int hil_mlc_register(hil_mlc *mlc);
  int hil_mlc_unregister(hil_mlc *mlc);