[deliverable/linux.git] / drivers / staging / dgrp / dgrp_common.c

/*
 *
 * Copyright 1999 Digi International (www.digi.com)
 *     James Puzzo <jamesp at digi dot com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU General Public License for more details.
 *
 */

/*
 *
 *  Filename:
 *
 *     dgrp_common.c
 *
 *  Description:
 *
 *     Definitions of global variables and functions which are either
 *     shared by the tty, mon, and net drivers; or which cross them
 *     functionally (like the poller).
 *
 *  Author:
 *
 *     James A. Puzzo
 *
 */

#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/sched.h>
#include <linux/cred.h>

#include "dgrp_common.h"

/**
 * dgrp_carrier -- check for carrier change state and act
 * @ch: struct ch_struct *
 */
void dgrp_carrier(struct ch_struct *ch)
{
	struct nd_struct *nd;

	int virt_carrier = 0;
	int phys_carrier = 0;

	/* fix case when the tty has already closed. */

	if (!ch)
		return;
	nd  = ch->ch_nd;
	if (!nd)
		return;

	/*
	 *  If we are currently waiting to determine the status of the port,
	 *  we don't yet know the state of the modem lines.  As a result,
	 *  we ignore state changes when we are waiting for the modem lines
	 *  to be established.  We know, as a result of code in dgrp_net_ops,
	 *  that we will be called again immediately following the reception
	 *  of the status message with the true modem status flags in it.
	 */
	if (ch->ch_expect & RR_STATUS)
		return;

	/*
	 * If CH_HANGUP is set, we gotta keep trying to get all the processes
	 * that have the port open to close the port.
	 * So lets just keep sending a hangup every time we get here.
	 */
	if ((ch->ch_flag & CH_HANGUP) &&
	    (ch->ch_tun.un_open_count > 0))
		tty_hangup(ch->ch_tun.un_tty);

	/*
	 *  Compute the effective state of both the physical and virtual
	 *  senses of carrier.
	 */

	if (ch->ch_s_mlast & DM_CD)
		phys_carrier = 1;

	if ((ch->ch_s_mlast & DM_CD) ||
	    (ch->ch_digi.digi_flags & DIGI_FORCEDCD) ||
	    (ch->ch_flag & CH_CLOCAL))
		virt_carrier = 1;

	/*
	 *  Test for a VIRTUAL carrier transition to HIGH.
	 *
	 *  The CH_HANGUP condition is intended to prevent any action
	 *  except for close.  As a result, we ignore positive carrier
	 *  transitions during CH_HANGUP.
	 */
	if (((ch->ch_flag & CH_HANGUP)  == 0) &&
	    ((ch->ch_flag & CH_VIRT_CD) == 0) &&
	    (virt_carrier == 1)) {
		/*
		 * When carrier rises, wake any threads waiting
		 * for carrier in the open routine.
		 */
		nd->nd_tx_work = 1;

		if (waitqueue_active(&ch->ch_flag_wait))
			wake_up_interruptible(&ch->ch_flag_wait);
	}

	/*
	 *  Test for a PHYSICAL transition to low, so long as we aren't
	 *  currently ignoring physical transitions (which is what "virtual
	 *  carrier" indicates).
	 *
	 *  The transition of the virtual carrier to low really doesn't
	 *  matter... it really only means "ignore carrier state", not
	 *  "make pretend that carrier is there".
	 */
	if ((virt_carrier == 0) &&
	    ((ch->ch_flag & CH_PHYS_CD) != 0) &&
	    (phys_carrier == 0)) {
		/*
		 * When carrier drops:
		 *
		 *   Do a Hard Hangup if that is called for.
		 *
		 *   Drop carrier on all open units.
		 *
		 *   Flush queues, waking up any task waiting in the
		 *   line discipline.
		 *
		 *   Send a hangup to the control terminal.
		 *
		 *   Enable all select calls.
		 */

		nd->nd_tx_work = 1;

		ch->ch_flag &= ~(CH_LOW | CH_EMPTY | CH_DRAIN | CH_INPUT);

		if (waitqueue_active(&ch->ch_flag_wait))
			wake_up_interruptible(&ch->ch_flag_wait);

		if (ch->ch_tun.un_open_count > 0)
			tty_hangup(ch->ch_tun.un_tty);

		if (ch->ch_pun.un_open_count > 0)
			tty_hangup(ch->ch_pun.un_tty);
	}

	/*
	 *  Make sure that our cached values reflect the current reality.
	 */
	if (virt_carrier == 1)
		ch->ch_flag |= CH_VIRT_CD;
	else
		ch->ch_flag &= ~CH_VIRT_CD;

	if (phys_carrier == 1)
		ch->ch_flag |= CH_PHYS_CD;
	else
		ch->ch_flag &= ~CH_PHYS_CD;

}
Commit	Line	Data
0b52b749 BP	1	/*
	2	*
	3	* Copyright 1999 Digi International (www.digi.com)
	4	* James Puzzo <jamesp at digi dot com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2, or (at your option)
	9	* any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
	13	* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
	14	* PURPOSE. See the GNU General Public License for more details.
	15	*
	16	*/
	17
	18	/*
	19	*
	20	* Filename:
	21	*
	22	* dgrp_common.c
	23	*
	24	* Description:
	25	*
	26	* Definitions of global variables and functions which are either
	27	* shared by the tty, mon, and net drivers; or which cross them
	28	* functionally (like the poller).
	29	*
	30	* Author:
	31	*
	32	* James A. Puzzo
	33	*
	34	*/
	35
	36	#include <linux/errno.h>
	37	#include <linux/tty.h>
	38	#include <linux/sched.h>
	39	#include <linux/cred.h>
	40
	41	#include "dgrp_common.h"
	42
	43	/**
	44	* dgrp_carrier -- check for carrier change state and act
	45	* @ch: struct ch_struct *
	46	*/
	47	void dgrp_carrier(struct ch_struct *ch)
	48	{
	49	struct nd_struct *nd;
	50
	51	int virt_carrier = 0;
	52	int phys_carrier = 0;
	53
	54	/* fix case when the tty has already closed. */
	55
	56	if (!ch)
	57	return;
	58	nd = ch->ch_nd;
	59	if (!nd)
	60	return;
	61
	62	/*
	63	* If we are currently waiting to determine the status of the port,
	64	* we don't yet know the state of the modem lines. As a result,
65	* we ignore state changes when we are waiting for the modem lines
66	* to be established. We know, as a result of code in dgrp_net_ops,
67	* that we will be called again immediately following the reception
68	* of the status message with the true modem status flags in it.
69	*/
70	if (ch->ch_expect & RR_STATUS)
71	return;
72
73	/*
74	* If CH_HANGUP is set, we gotta keep trying to get all the processes
75	* that have the port open to close the port.
76	* So lets just keep sending a hangup every time we get here.
77	*/
78	if ((ch->ch_flag & CH_HANGUP) &&
79	(ch->ch_tun.un_open_count > 0))
80	tty_hangup(ch->ch_tun.un_tty);
81
82	/*
83	* Compute the effective state of both the physical and virtual
84	* senses of carrier.
85	*/
86
87	if (ch->ch_s_mlast & DM_CD)
88	phys_carrier = 1;
89
90	if ((ch->ch_s_mlast & DM_CD) \|\|
91	(ch->ch_digi.digi_flags & DIGI_FORCEDCD) \|\|
92	(ch->ch_flag & CH_CLOCAL))
93	virt_carrier = 1;
94
95	/*
96	* Test for a VIRTUAL carrier transition to HIGH.
97	*
98	* The CH_HANGUP condition is intended to prevent any action
99	* except for close. As a result, we ignore positive carrier
100	* transitions during CH_HANGUP.
101	*/
102	if (((ch->ch_flag & CH_HANGUP) == 0) &&
103	((ch->ch_flag & CH_VIRT_CD) == 0) &&
104	(virt_carrier == 1)) {
105	/*
106	* When carrier rises, wake any threads waiting
107	* for carrier in the open routine.
108	*/
109	nd->nd_tx_work = 1;
110
111	if (waitqueue_active(&ch->ch_flag_wait))
112	wake_up_interruptible(&ch->ch_flag_wait);
113	}
114
115	/*
116	* Test for a PHYSICAL transition to low, so long as we aren't
117	* currently ignoring physical transitions (which is what "virtual
118	* carrier" indicates).
119	*
120	* The transition of the virtual carrier to low really doesn't
121	* matter... it really only means "ignore carrier state", not
122	* "make pretend that carrier is there".
123	*/
124	if ((virt_carrier == 0) &&
125	((ch->ch_flag & CH_PHYS_CD) != 0) &&
126	(phys_carrier == 0)) {
127	/*
128	* When carrier drops:
129	*
130	* Do a Hard Hangup if that is called for.
131	*
132	* Drop carrier on all open units.
133	*
134	* Flush queues, waking up any task waiting in the
135	* line discipline.
136	*
137	* Send a hangup to the control terminal.
138	*
139	* Enable all select calls.
140	*/
141
142	nd->nd_tx_work = 1;
143
144	ch->ch_flag &= ~(CH_LOW \| CH_EMPTY \| CH_DRAIN \| CH_INPUT);
145
146	if (waitqueue_active(&ch->ch_flag_wait))
147	wake_up_interruptible(&ch->ch_flag_wait);
148
149	if (ch->ch_tun.un_open_count > 0)
150	tty_hangup(ch->ch_tun.un_tty);
151
152	if (ch->ch_pun.un_open_count > 0)
153	tty_hangup(ch->ch_pun.un_tty);
154	}
155
156	/*
157	* Make sure that our cached values reflect the current reality.
158	*/
159	if (virt_carrier == 1)
160	ch->ch_flag \|= CH_VIRT_CD;
161	else
162	ch->ch_flag &= ~CH_VIRT_CD;
163
164	if (phys_carrier == 1)
165	ch->ch_flag \|= CH_PHYS_CD;
166	else
167	ch->ch_flag &= ~CH_PHYS_CD;
168
169	}