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tty_port: Add a port level carrier detect operation

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This is the first step to generalising the various pieces of waiting logic
duplicated in all sorts of serial drivers.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox
2009-01-02 13:45:05 +00:00
committed by Linus Torvalds
parent c9b3976e3f
commit 31f35939d1
19 changed files with 428 additions and 240 deletions
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61
drivers/char/esp.c
View File

@@ -2054,6 +2054,15 @@ static void esp_hangup(struct tty_struct *tty)
wake_up_interruptible(&info->port.open_wait);
}
static int esp_carrier_raised(struct tty_port *port)
{
struct esp_struct *info = container_of(port, struct esp_struct, port);
serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
if (serial_in(info, UART_ESI_STAT2) & UART_MSR_DCD)
return 1;
return 0;
}
/*
* ------------------------------------------------------------
* esp_open() and friends
@@ -2066,17 +2075,19 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
int retval;
int do_clocal = 0;
unsigned long flags;
int cd;
struct tty_port *port = &info->port;
/*
* If the device is in the middle of being closed, then block
* until it's done, and then try again.
*/
if (tty_hung_up_p(filp) ||
(info->port.flags & ASYNC_CLOSING)) {
if (info->port.flags & ASYNC_CLOSING)
interruptible_sleep_on(&info->port.close_wait);
(port->flags & ASYNC_CLOSING)) {
if (port->flags & ASYNC_CLOSING)
interruptible_sleep_on(&port->close_wait);
#ifdef SERIAL_DO_RESTART
if (info->port.flags & ASYNC_HUP_NOTIFY)
if (port->flags & ASYNC_HUP_NOTIFY)
return -EAGAIN;
else
return -ERESTARTSYS;
@@ -2091,7 +2102,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
*/
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
info->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
@@ -2101,20 +2112,20 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
/*
* Block waiting for the carrier detect and the line to become
* free (i.e., not in use by the callout). While we are in
* this loop, info->port.count is dropped by one, so that
* this loop, port->count is dropped by one, so that
* rs_close() knows when to free things. We restore it upon
* exit, either normal or abnormal.
*/
retval = 0;
add_wait_queue(&info->port.open_wait, &wait);
add_wait_queue(&port->open_wait, &wait);
#ifdef SERIAL_DEBUG_OPEN
printk(KERN_DEBUG "block_til_ready before block: ttys%d, count = %d\n",
info->line, info->port.count);
info->line, port->count);
#endif
spin_lock_irqsave(&info->lock, flags);
if (!tty_hung_up_p(filp))
info->port.count--;
info->port.blocked_open++;
port->count--;
port->blocked_open++;
while (1) {
if ((tty->termios->c_cflag & CBAUD)) {
unsigned int scratch;
@@ -2129,9 +2140,9 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
}
set_current_state(TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) ||
!(info->port.flags & ASYNC_INITIALIZED)) {
!(port->flags & ASYNC_INITIALIZED)) {
#ifdef SERIAL_DO_RESTART
if (info->port.flags & ASYNC_HUP_NOTIFY)
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
@@ -2141,11 +2152,9 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
break;
}
serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
if (serial_in(info, UART_ESI_STAT2) & UART_MSR_DCD)
do_clocal = 1;
cd = tty_port_carrier_raised(port);
if (!(info->port.flags & ASYNC_CLOSING) &&
if (!(port->flags & ASYNC_CLOSING) &&
(do_clocal))
break;
if (signal_pending(current)) {
@@ -2154,25 +2163,25 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
}
#ifdef SERIAL_DEBUG_OPEN
printk(KERN_DEBUG "block_til_ready blocking: ttys%d, count = %d\n",
info->line, info->port.count);
info->line, port->count);
#endif
spin_unlock_irqrestore(&info->lock, flags);
schedule();
spin_lock_irqsave(&info->lock, flags);
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&info->port.open_wait, &wait);
remove_wait_queue(&port->open_wait, &wait);
if (!tty_hung_up_p(filp))
info->port.count++;
info->port.blocked_open--;
port->count++;
port->blocked_open--;
spin_unlock_irqrestore(&info->lock, flags);
#ifdef SERIAL_DEBUG_OPEN
printk(KERN_DEBUG "block_til_ready after blocking: ttys%d, count = %d\n",
info->line, info->port.count);
info->line, port->count);
#endif
if (retval)
return retval;
info->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
@@ -2329,6 +2338,10 @@ static const struct tty_operations esp_ops = {
.tiocmset = esp_tiocmset,
};
static const struct tty_port_operations esp_port_ops = {
.esp_carrier_raised,
};
/*
* The serial driver boot-time initialization code!
*/
@@ -2415,6 +2428,8 @@ static int __init espserial_init(void)
offset = 0;
do {
tty_port_init(&info->port);
info->port.ops = &esp_port_ops;
info->io_port = esp[i] + offset;
info->irq = irq[i];
info->line = (i * 8) + (offset / 8);
@@ -2437,8 +2452,6 @@ static int __init espserial_init(void)
info->config.flow_off = flow_off;
info->config.pio_threshold = pio_threshold;
info->next_port = ports;
init_waitqueue_head(&info->port.open_wait);
init_waitqueue_head(&info->port.close_wait);
init_waitqueue_head(&info->delta_msr_wait);
init_waitqueue_head(&info->break_wait);
ports = info;