1/*
2 * HP Human Interface Loop Master Link Controller driver.
3 *
4 * Copyright (c) 2001 Brian S. Julin
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions, and the following disclaimer,
12 *    without modification.
13 * 2. The name of the author may not be used to endorse or promote products
14 *    derived from this software without specific prior written permission.
15 *
16 * Alternatively, this software may be distributed under the terms of the
17 * GNU General Public License ("GPL").
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 *
29 * References:
30 * HP-HIL Technical Reference Manual.  Hewlett Packard Product No. 45918A
31 *
32 */
33
34#include <linux/hil.h>
35#include <linux/time.h>
36#include <linux/interrupt.h>
37#include <linux/semaphore.h>
38#include <linux/serio.h>
39#include <linux/list.h>
40
41typedef struct hil_mlc hil_mlc;
42
43/* The HIL has a complicated state engine.
44 * We define the structure of nodes in the state engine here.
45 */
46enum hilse_act {
47  	/* HILSE_OUT prepares to receive input if the next node
48	 * is an IN or EXPECT, and then sends the given packet.
49	 */
50	HILSE_OUT = 0,
51
52  	/* HILSE_CTS checks if the loop is busy. */
53	HILSE_CTS,
54
55	/* HILSE_OUT_LAST sends the given command packet to
56	 * the last configured/running device on the loop.
57	 */
58	HILSE_OUT_LAST,
59
60	/* HILSE_OUT_DISC sends the given command packet to
61	 * the next device past the last configured/running one.
62	 */
63	HILSE_OUT_DISC,
64
65	/* HILSE_FUNC runs a callback function with given arguments.
66	 * a positive return value causes the "ugly" branch to be taken.
67	 */
68	HILSE_FUNC,
69
70  	/* HILSE_IN simply expects any non-errored packet to arrive
71	 * within arg usecs.
72	 */
73	HILSE_IN		= 0x100,
74
75  	/* HILSE_EXPECT expects a particular packet to arrive
76	 * within arg usecs, any other packet is considered an error.
77	 */
78	HILSE_EXPECT,
79
80  	/* HILSE_EXPECT_LAST as above but dev field should be last
81	 * discovered/operational device.
82	 */
83	HILSE_EXPECT_LAST,
84
85  	/* HILSE_EXPECT_LAST as above but dev field should be first
86	 * undiscovered/inoperational device.
87	 */
88	HILSE_EXPECT_DISC
89};
90
91typedef int	(hilse_func) (hil_mlc *mlc, int arg);
92struct hilse_node {
93	enum hilse_act		act;	/* How to process this node         */
94	union {
95		hilse_func	*func;	/* Function to call if HILSE_FUNC   */
96		hil_packet	packet;	/* Packet to send or to compare     */
97	} object;
98	int			arg;	/* Timeout in usec or parm for func */
99	int			good;	/* Node to jump to on success       */
100	int			bad;	/* Node to jump to on error         */
101	int			ugly;	/* Node to jump to on timeout       */
102};
103
104/* Methods for back-end drivers, e.g. hp_sdc_mlc */
105typedef int	(hil_mlc_cts) (hil_mlc *mlc);
106typedef int	(hil_mlc_out) (hil_mlc *mlc);
107typedef int	(hil_mlc_in)  (hil_mlc *mlc, suseconds_t timeout);
108
109struct hil_mlc_devinfo {
110	uint8_t	idd[16];	/* Device ID Byte and Describe Record */
111	uint8_t	rsc[16];	/* Security Code Header and Record */
112	uint8_t	exd[16];	/* Extended Describe Record */
113	uint8_t	rnm[16];	/* Device name as returned by RNM command */
114};
115
116struct hil_mlc_serio_map {
117	hil_mlc *mlc;
118	int di_revmap;
119	int didx;
120};
121
122/* How many (possibly old/detached) devices the we try to keep track of */
123#define HIL_MLC_DEVMEM 16
124
125struct hil_mlc {
126	struct list_head	list;	/* hil_mlc is organized as linked list */
127
128	rwlock_t		lock;
129
130	void *priv; /* Data specific to a particular type of MLC */
131
132	int 			seidx;	/* Current node in state engine */
133	int			istarted, ostarted;
134
135	hil_mlc_cts		*cts;
136	struct semaphore	csem;   /* Raised when loop idle */
137
138	hil_mlc_out		*out;
139	struct semaphore	osem;   /* Raised when outpacket dispatched */
140	hil_packet		opacket;
141
142	hil_mlc_in		*in;
143	struct semaphore	isem;   /* Raised when a packet arrives */
144	hil_packet		ipacket[16];
145	hil_packet		imatch;
146	int			icount;
147	unsigned long		instart;
148	unsigned long		intimeout;
149
150	int			ddi;	/* Last operational device id */
151	int			lcv;	/* LCV to throttle loops */
152	time64_t		lcv_time; /* Time loop was started */
153
154	int			di_map[7]; /* Maps below items to live devs */
155	struct hil_mlc_devinfo	di[HIL_MLC_DEVMEM];
156	struct serio		*serio[HIL_MLC_DEVMEM];
157	struct hil_mlc_serio_map serio_map[HIL_MLC_DEVMEM];
158	hil_packet		serio_opacket[HIL_MLC_DEVMEM];
159	int			serio_oidx[HIL_MLC_DEVMEM];
160	struct hil_mlc_devinfo	di_scratch; /* Temporary area */
161
162	int			opercnt;
163
164	struct tasklet_struct	*tasklet;
165};
166
167int hil_mlc_register(hil_mlc *mlc);
168int hil_mlc_unregister(hil_mlc *mlc);
169