hil_mlc.h

Go to the documentation of this file.

/*
 * 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);