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linux/drivers/isdn/gigaset/interface.c
Tilman Schmidt 7435f50e12 [PATCH] drivers/isdn/gigaset: reduce mutex scope 
Do not lock the cardstate structure mutex earlier than necessary.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:29 -08:00

725 lines
17 KiB
C
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/*
* interface to user space for the gigaset driver
*
* Copyright (c) 2004 by Hansjoerg Lipp <hjlipp@web.de>
*
* =====================================================================
* 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 of
* the License, or (at your option) any later version.
* =====================================================================
*/
#include "gigaset.h"
#include <linux/gigaset_dev.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
/*** our ioctls ***/
static int if_lock(struct cardstate *cs, int *arg)
{
int cmd = *arg;
gig_dbg(DEBUG_IF, "%u: if_lock (%d)", cs->minor_index, cmd);
if (cmd > 1)
return -EINVAL;
if (cmd < 0) {
*arg = atomic_read(&cs->mstate) == MS_LOCKED; //FIXME remove?
return 0;
}
if (!cmd && atomic_read(&cs->mstate) == MS_LOCKED
&& cs->connected) {
cs->ops->set_modem_ctrl(cs, 0, TIOCM_DTR|TIOCM_RTS);
cs->ops->baud_rate(cs, B115200);
cs->ops->set_line_ctrl(cs, CS8);
cs->control_state = TIOCM_DTR|TIOCM_RTS;
}
cs->waiting = 1;
if (!gigaset_add_event(cs, &cs->at_state, EV_IF_LOCK,
NULL, cmd, NULL)) {
cs->waiting = 0;
return -ENOMEM;
}
gig_dbg(DEBUG_CMD, "scheduling IF_LOCK");
gigaset_schedule_event(cs);
wait_event(cs->waitqueue, !cs->waiting);
if (cs->cmd_result >= 0) {
*arg = cs->cmd_result;
return 0;
}
return cs->cmd_result;
}
static int if_version(struct cardstate *cs, unsigned arg[4])
{
static const unsigned version[4] = GIG_VERSION;
static const unsigned compat[4] = GIG_COMPAT;
unsigned cmd = arg[0];
gig_dbg(DEBUG_IF, "%u: if_version (%d)", cs->minor_index, cmd);
switch (cmd) {
case GIGVER_DRIVER:
memcpy(arg, version, sizeof version);
return 0;
case GIGVER_COMPAT:
memcpy(arg, compat, sizeof compat);
return 0;
case GIGVER_FWBASE:
cs->waiting = 1;
if (!gigaset_add_event(cs, &cs->at_state, EV_IF_VER,
NULL, 0, arg)) {
cs->waiting = 0;
return -ENOMEM;
}
gig_dbg(DEBUG_CMD, "scheduling IF_VER");
gigaset_schedule_event(cs);
wait_event(cs->waitqueue, !cs->waiting);
if (cs->cmd_result >= 0)
return 0;
return cs->cmd_result;
default:
return -EINVAL;
}
}
static int if_config(struct cardstate *cs, int *arg)
{
gig_dbg(DEBUG_IF, "%u: if_config (%d)", cs->minor_index, *arg);
if (*arg != 1)
return -EINVAL;
if (atomic_read(&cs->mstate) != MS_LOCKED)
return -EBUSY;
if (!cs->connected) {
err("not connected!");
return -ENODEV;
}
*arg = 0;
return gigaset_enterconfigmode(cs);
}
/*** the terminal driver ***/
/* stolen from usbserial and some other tty drivers */
static int if_open(struct tty_struct *tty, struct file *filp);
static void if_close(struct tty_struct *tty, struct file *filp);
static int if_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg);
static int if_write_room(struct tty_struct *tty);
static int if_chars_in_buffer(struct tty_struct *tty);
static void if_throttle(struct tty_struct *tty);
static void if_unthrottle(struct tty_struct *tty);
static void if_set_termios(struct tty_struct *tty, struct ktermios *old);
static int if_tiocmget(struct tty_struct *tty, struct file *file);
static int if_tiocmset(struct tty_struct *tty, struct file *file,
unsigned int set, unsigned int clear);
static int if_write(struct tty_struct *tty,
const unsigned char *buf, int count);
static const struct tty_operations if_ops = {
.open = if_open,
.close = if_close,
.ioctl = if_ioctl,
.write = if_write,
.write_room = if_write_room,
.chars_in_buffer = if_chars_in_buffer,
.set_termios = if_set_termios,
.throttle = if_throttle,
.unthrottle = if_unthrottle,
#if 0
.break_ctl = serial_break,
#endif
.tiocmget = if_tiocmget,
.tiocmset = if_tiocmset,
};
static int if_open(struct tty_struct *tty, struct file *filp)
{
struct cardstate *cs;
unsigned long flags;
gig_dbg(DEBUG_IF, "%d+%d: %s()",
tty->driver->minor_start, tty->index, __func__);
tty->driver_data = NULL;
cs = gigaset_get_cs_by_tty(tty);
if (!cs)
return -ENODEV;
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?
tty->driver_data = cs;
++cs->open_count;
if (cs->open_count == 1) {
spin_lock_irqsave(&cs->lock, flags);
cs->tty = tty;
spin_unlock_irqrestore(&cs->lock, flags);
tty->low_latency = 1; //FIXME test
}
mutex_unlock(&cs->mutex);
return 0;
}
static void if_close(struct tty_struct *tty, struct file *filp)
{
struct cardstate *cs;
unsigned long flags;
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return;
}
gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
mutex_lock(&cs->mutex);
if (!cs->open_count)
warn("%s: device not opened", __func__);
else {
if (!--cs->open_count) {
spin_lock_irqsave(&cs->lock, flags);
cs->tty = NULL;
spin_unlock_irqrestore(&cs->lock, flags);
}
}
mutex_unlock(&cs->mutex);
}
static int if_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct cardstate *cs;
int retval = -ENODEV;
int int_arg;
unsigned char buf[6];
unsigned version[4];
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return -ENODEV;
}
gig_dbg(DEBUG_IF, "%u: %s(0x%x)", cs->minor_index, __func__, cmd);
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?
if (!cs->open_count)
warn("%s: device not opened", __func__);
else {
retval = 0;
switch (cmd) {
case GIGASET_REDIR:
retval = get_user(int_arg, (int __user *) arg);
if (retval >= 0)
retval = if_lock(cs, &int_arg);
if (retval >= 0)
retval = put_user(int_arg, (int __user *) arg);
break;
case GIGASET_CONFIG:
retval = get_user(int_arg, (int __user *) arg);
if (retval >= 0)
retval = if_config(cs, &int_arg);
if (retval >= 0)
retval = put_user(int_arg, (int __user *) arg);
break;
case GIGASET_BRKCHARS:
//FIXME test if MS_LOCKED
if (!cs->connected) {
gig_dbg(DEBUG_ANY,
"can't communicate with unplugged device");
retval = -ENODEV;
break;
}
retval = copy_from_user(&buf,
(const unsigned char __user *) arg, 6)
? -EFAULT : 0;
if (retval >= 0) {
gigaset_dbg_buffer(DEBUG_IF, "GIGASET_BRKCHARS",
6, (const unsigned char *) arg);
retval = cs->ops->brkchars(cs, buf);
}
break;
case GIGASET_VERSION:
retval = copy_from_user(version,
(unsigned __user *) arg, sizeof version)
? -EFAULT : 0;
if (retval >= 0)
retval = if_version(cs, version);
if (retval >= 0)
retval = copy_to_user((unsigned __user *) arg,
version, sizeof version)
? -EFAULT : 0;
break;
default:
gig_dbg(DEBUG_ANY, "%s: arg not supported - 0x%04x",
__func__, cmd);
retval = -ENOIOCTLCMD;
}
}
mutex_unlock(&cs->mutex);
return retval;
}
static int if_tiocmget(struct tty_struct *tty, struct file *file)
{
struct cardstate *cs;
int retval;
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return -ENODEV;
}
gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?
// FIXME read from device?
retval = cs->control_state & (TIOCM_RTS|TIOCM_DTR);
mutex_unlock(&cs->mutex);
return retval;
}
static int if_tiocmset(struct tty_struct *tty, struct file *file,
unsigned int set, unsigned int clear)
{
struct cardstate *cs;
int retval;
unsigned mc;
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return -ENODEV;
}
gig_dbg(DEBUG_IF, "%u: %s(0x%x, 0x%x)",
cs->minor_index, __func__, set, clear);
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?
if (!cs->connected) {
gig_dbg(DEBUG_ANY, "can't communicate with unplugged device");
retval = -ENODEV;
} else {
mc = (cs->control_state | set) & ~clear & (TIOCM_RTS|TIOCM_DTR);
retval = cs->ops->set_modem_ctrl(cs, cs->control_state, mc);
cs->control_state = mc;
}
mutex_unlock(&cs->mutex);
return retval;
}
static int if_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
struct cardstate *cs;
int retval = -ENODEV;
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return -ENODEV;
}
gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?
if (!cs->open_count)
warn("%s: device not opened", __func__);
else if (atomic_read(&cs->mstate) != MS_LOCKED) {
warn("can't write to unlocked device");
retval = -EBUSY;
} else if (!cs->connected) {
gig_dbg(DEBUG_ANY, "can't write to unplugged device");
retval = -EBUSY; //FIXME
} else {
retval = cs->ops->write_cmd(cs, buf, count,
&cs->if_wake_tasklet);
}
mutex_unlock(&cs->mutex);
return retval;
}
static int if_write_room(struct tty_struct *tty)
{
struct cardstate *cs;
int retval = -ENODEV;
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return -ENODEV;
}
gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?
if (!cs->open_count)
warn("%s: device not opened", __func__);
else if (atomic_read(&cs->mstate) != MS_LOCKED) {
warn("can't write to unlocked device");
retval = -EBUSY; //FIXME
} else if (!cs->connected) {
gig_dbg(DEBUG_ANY, "can't write to unplugged device");
retval = -EBUSY; //FIXME
} else
retval = cs->ops->write_room(cs);
mutex_unlock(&cs->mutex);
return retval;
}
static int if_chars_in_buffer(struct tty_struct *tty)
{
struct cardstate *cs;
int retval = -ENODEV;
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return -ENODEV;
}
gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?
if (!cs->open_count)
warn("%s: device not opened", __func__);
else if (atomic_read(&cs->mstate) != MS_LOCKED) {
warn("can't write to unlocked device");
retval = -EBUSY;
} else if (!cs->connected) {
gig_dbg(DEBUG_ANY, "can't write to unplugged device");
retval = -EBUSY; //FIXME
} else
retval = cs->ops->chars_in_buffer(cs);
mutex_unlock(&cs->mutex);
return retval;
}
static void if_throttle(struct tty_struct *tty)
{
struct cardstate *cs;
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return;
}
gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
mutex_lock(&cs->mutex);
if (!cs->open_count)
warn("%s: device not opened", __func__);
else {
//FIXME
}
mutex_unlock(&cs->mutex);
}
static void if_unthrottle(struct tty_struct *tty)
{
struct cardstate *cs;
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return;
}
gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
mutex_lock(&cs->mutex);
if (!cs->open_count)
warn("%s: device not opened", __func__);
else {
//FIXME
}
mutex_unlock(&cs->mutex);
}
static void if_set_termios(struct tty_struct *tty, struct ktermios *old)
{
struct cardstate *cs;
unsigned int iflag;
unsigned int cflag;
unsigned int old_cflag;
unsigned int control_state, new_state;
cs = (struct cardstate *) tty->driver_data;
if (!cs) {
err("cs==NULL in %s", __func__);
return;
}
gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
mutex_lock(&cs->mutex);
if (!cs->open_count) {
warn("%s: device not opened", __func__);
goto out;
}
if (!cs->connected) {
gig_dbg(DEBUG_ANY, "can't communicate with unplugged device");
goto out;
}
// stolen from mct_u232.c
iflag = tty->termios->c_iflag;
cflag = tty->termios->c_cflag;
old_cflag = old ? old->c_cflag : cflag; //FIXME?
gig_dbg(DEBUG_IF, "%u: iflag %x cflag %x old %x",
cs->minor_index, iflag, cflag, old_cflag);
/* get a local copy of the current port settings */
control_state = cs->control_state;
/*
* Update baud rate.
* Do not attempt to cache old rates and skip settings,
* disconnects screw such tricks up completely.
* Premature optimization is the root of all evil.
*/
/* reassert DTR and (maybe) RTS on transition from B0 */
if ((old_cflag & CBAUD) == B0) {
new_state = control_state | TIOCM_DTR;
/* don't set RTS if using hardware flow control */
if (!(old_cflag & CRTSCTS))
new_state |= TIOCM_RTS;
gig_dbg(DEBUG_IF, "%u: from B0 - set DTR%s",
cs->minor_index,
(new_state & TIOCM_RTS) ? " only" : "/RTS");
cs->ops->set_modem_ctrl(cs, control_state, new_state);
control_state = new_state;
}
cs->ops->baud_rate(cs, cflag & CBAUD);
if ((cflag & CBAUD) == B0) {
/* Drop RTS and DTR */
gig_dbg(DEBUG_IF, "%u: to B0 - drop DTR/RTS", cs->minor_index);
new_state = control_state & ~(TIOCM_DTR | TIOCM_RTS);
cs->ops->set_modem_ctrl(cs, control_state, new_state);
control_state = new_state;
}
/*
* Update line control register (LCR)
*/
cs->ops->set_line_ctrl(cs, cflag);
#if 0
//FIXME this hangs M101 [ts 2005-03-09]
//FIXME do we need this?
/*
* Set flow control: well, I do not really now how to handle DTR/RTS.
* Just do what we have seen with SniffUSB on Win98.
*/
/* Drop DTR/RTS if no flow control otherwise assert */
gig_dbg(DEBUG_IF, "%u: control_state %x",
cs->minor_index, control_state);
new_state = control_state;
if ((iflag & IXOFF) || (iflag & IXON) || (cflag & CRTSCTS))
new_state |= TIOCM_DTR | TIOCM_RTS;
else
new_state &= ~(TIOCM_DTR | TIOCM_RTS);
if (new_state != control_state) {
gig_dbg(DEBUG_IF, "%u: new_state %x",
cs->minor_index, new_state);
gigaset_set_modem_ctrl(cs, control_state, new_state);
control_state = new_state;
}
#endif
/* save off the modified port settings */
cs->control_state = control_state;
out:
mutex_unlock(&cs->mutex);
}
/* wakeup tasklet for the write operation */
static void if_wake(unsigned long data)
{
struct cardstate *cs = (struct cardstate *) data;
if (cs->tty)
tty_wakeup(cs->tty);
}
/*** interface to common ***/
void gigaset_if_init(struct cardstate *cs)
{
struct gigaset_driver *drv;
drv = cs->driver;
if (!drv->have_tty)
return;
tasklet_init(&cs->if_wake_tasklet, &if_wake, (unsigned long) cs);
mutex_lock(&cs->mutex);
cs->tty_dev = tty_register_device(drv->tty, cs->minor_index, NULL);
if (!IS_ERR(cs->tty_dev))
dev_set_drvdata(cs->tty_dev, cs);
else {
warn("could not register device to the tty subsystem");
cs->tty_dev = NULL;
}
mutex_unlock(&cs->mutex);
}
void gigaset_if_free(struct cardstate *cs)
{
struct gigaset_driver *drv;
drv = cs->driver;
if (!drv->have_tty)
return;
tasklet_disable(&cs->if_wake_tasklet);
tasklet_kill(&cs->if_wake_tasklet);
cs->tty_dev = NULL;
tty_unregister_device(drv->tty, cs->minor_index);
}
void gigaset_if_receive(struct cardstate *cs,
unsigned char *buffer, size_t len)
{
unsigned long flags;
struct tty_struct *tty;
spin_lock_irqsave(&cs->lock, flags);
if ((tty = cs->tty) == NULL)
gig_dbg(DEBUG_ANY, "receive on closed device");
else {
tty_buffer_request_room(tty, len);
tty_insert_flip_string(tty, buffer, len);
tty_flip_buffer_push(tty);
}
spin_unlock_irqrestore(&cs->lock, flags);
}
EXPORT_SYMBOL_GPL(gigaset_if_receive);
/* gigaset_if_initdriver
* Initialize tty interface.
* parameters:
* drv Driver
* procname Name of the driver (e.g. for /proc/tty/drivers)
* devname Name of the device files (prefix without minor number)
*/
void gigaset_if_initdriver(struct gigaset_driver *drv, const char *procname,
const char *devname)
{
unsigned minors = drv->minors;
int ret;
struct tty_driver *tty;
drv->have_tty = 0;
if ((drv->tty = alloc_tty_driver(minors)) == NULL)
goto enomem;
tty = drv->tty;
tty->magic = TTY_DRIVER_MAGIC,
tty->major = GIG_MAJOR,
tty->type = TTY_DRIVER_TYPE_SERIAL,
tty->subtype = SERIAL_TYPE_NORMAL,
tty->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
tty->driver_name = procname;
tty->name = devname;
tty->minor_start = drv->minor;
tty->num = drv->minors;
tty->owner = THIS_MODULE;
tty->init_termios = tty_std_termios; //FIXME
tty->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL; //FIXME
tty_set_operations(tty, &if_ops);
ret = tty_register_driver(tty);
if (ret < 0) {
warn("failed to register tty driver (error %d)", ret);
goto error;
}
gig_dbg(DEBUG_IF, "tty driver initialized");
drv->have_tty = 1;
return;
enomem:
warn("could not allocate tty structures");
error:
if (drv->tty)
put_tty_driver(drv->tty);
}
void gigaset_if_freedriver(struct gigaset_driver *drv)
{
if (!drv->have_tty)
return;
drv->have_tty = 0;
tty_unregister_driver(drv->tty);
put_tty_driver(drv->tty);
}
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