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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>
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Alan Cox authored and Linus Torvalds committed Jan 2, 2009
1 parent c9b3976 commit 31f3593
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Showing 19 changed files with 427 additions and 239 deletions.
61 changes: 37 additions & 24 deletions drivers/char/esp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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;
Expand All @@ -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;
}

Expand All @@ -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;
Expand All @@ -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;
Expand All @@ -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)) {
Expand All @@ -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;
}

Expand Down Expand Up @@ -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!
*/
Expand Down Expand Up @@ -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);
Expand All @@ -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;
Expand Down
43 changes: 22 additions & 21 deletions drivers/char/generic_serial.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -397,7 +397,8 @@ void gs_hangup(struct tty_struct *tty)

int gs_block_til_ready(void *port_, struct file * filp)
{
struct gs_port *port = port_;
struct gs_port *gp = port_;
struct tty_port *port = &gp->port;
DECLARE_WAITQUEUE(wait, current);
int retval;
int do_clocal = 0;
Expand All @@ -409,16 +410,16 @@ int gs_block_til_ready(void *port_, struct file * filp)

if (!port) return 0;

tty = port->port.tty;
tty = port->tty;

gs_dprintk (GS_DEBUG_BTR, "Entering gs_block_till_ready.\n");
/*
* 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) || port->port.flags & ASYNC_CLOSING) {
interruptible_sleep_on(&port->port.close_wait);
if (port->port.flags & ASYNC_HUP_NOTIFY)
if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
interruptible_sleep_on(&port->close_wait);
if (port->flags & ASYNC_HUP_NOTIFY)
return -EAGAIN;
else
return -ERESTARTSYS;
Expand All @@ -432,7 +433,7 @@ int gs_block_til_ready(void *port_, struct file * filp)
*/
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
port->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}

Expand All @@ -444,34 +445,34 @@ int gs_block_til_ready(void *port_, 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, port->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(&port->port.open_wait, &wait);
add_wait_queue(&port->open_wait, &wait);

gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n");
spin_lock_irqsave(&port->driver_lock, flags);
spin_lock_irqsave(&gp->driver_lock, flags);
if (!tty_hung_up_p(filp)) {
port->port.count--;
port->count--;
}
spin_unlock_irqrestore(&port->driver_lock, flags);
port->port.blocked_open++;
spin_unlock_irqrestore(&gp->driver_lock, flags);
port->blocked_open++;
while (1) {
CD = port->rd->get_CD (port);
CD = tty_port_carrier_raised(port);
gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
set_current_state (TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) ||
!(port->port.flags & ASYNC_INITIALIZED)) {
if (port->port.flags & ASYNC_HUP_NOTIFY)
!(port->flags & ASYNC_INITIALIZED)) {
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
break;
}
if (!(port->port.flags & ASYNC_CLOSING) &&
if (!(port->flags & ASYNC_CLOSING) &&
(do_clocal || CD))
break;
gs_dprintk (GS_DEBUG_BTR, "signal_pending is now: %d (%lx)\n",
Expand All @@ -483,17 +484,17 @@ int gs_block_til_ready(void *port_, struct file * filp)
schedule();
}
gs_dprintk (GS_DEBUG_BTR, "Got out of the loop. (%d)\n",
port->port.blocked_open);
port->blocked_open);
set_current_state (TASK_RUNNING);
remove_wait_queue(&port->port.open_wait, &wait);
remove_wait_queue(&port->open_wait, &wait);
if (!tty_hung_up_p(filp)) {
port->port.count++;
port->count++;
}
port->port.blocked_open--;
port->blocked_open--;
if (retval)
return retval;

port->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
func_exit ();
return 0;
}
Expand Down
51 changes: 32 additions & 19 deletions drivers/char/isicom.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -830,20 +830,28 @@ static int isicom_setup_port(struct tty_struct *tty)
return 0;
}

static int isicom_carrier_raised(struct tty_port *port)
{
struct isi_port *ip = container_of(port, struct isi_port, port);
return (ip->status & ISI_DCD)?1 : 0;
}

static int block_til_ready(struct tty_struct *tty, struct file *filp,
struct isi_port *port)
struct isi_port *ip)
{
struct isi_board *card = port->card;
struct isi_board *card = ip->card;
struct tty_port *port = &ip->port;
int do_clocal = 0, retval;
unsigned long flags;
DECLARE_WAITQUEUE(wait, current);
int cd;

/* block if port is in the process of being closed */

if (tty_hung_up_p(filp) || port->port.flags & ASYNC_CLOSING) {
if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
pr_dbg("block_til_ready: close in progress.\n");
interruptible_sleep_on(&port->port.close_wait);
if (port->port.flags & ASYNC_HUP_NOTIFY)
interruptible_sleep_on(&port->close_wait);
if (port->flags & ASYNC_HUP_NOTIFY)
return -EAGAIN;
else
return -ERESTARTSYS;
Expand All @@ -854,7 +862,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
pr_dbg("block_til_ready: non-block mode.\n");
port->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}

Expand All @@ -864,45 +872,45 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
/* block waiting for DCD to be asserted, and while
callout dev is busy */
retval = 0;
add_wait_queue(&port->port.open_wait, &wait);
add_wait_queue(&port->open_wait, &wait);

spin_lock_irqsave(&card->card_lock, flags);
if (!tty_hung_up_p(filp))
port->port.count--;
port->port.blocked_open++;
port->count--;
port->blocked_open++;
spin_unlock_irqrestore(&card->card_lock, flags);

while (1) {
raise_dtr_rts(port);
raise_dtr_rts(ip);

set_current_state(TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) || !(port->port.flags & ASYNC_INITIALIZED)) {
if (port->port.flags & ASYNC_HUP_NOTIFY)
if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
break;
}
if (!(port->port.flags & ASYNC_CLOSING) &&
(do_clocal || (port->status & ISI_DCD))) {
cd = tty_port_carrier_raised(port);
if (!(port->flags & ASYNC_CLOSING) &&
(do_clocal || cd))
break;
}
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
schedule();
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&port->port.open_wait, &wait);
remove_wait_queue(&port->open_wait, &wait);
spin_lock_irqsave(&card->card_lock, flags);
if (!tty_hung_up_p(filp))
port->port.count++;
port->port.blocked_open--;
port->count++;
port->blocked_open--;
spin_unlock_irqrestore(&card->card_lock, flags);
if (retval)
return retval;
port->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}

Expand Down Expand Up @@ -1452,6 +1460,10 @@ static const struct tty_operations isicom_ops = {
.break_ctl = isicom_send_break,
};

static const struct tty_port_operations isicom_port_ops = {
.carrier_raised = isicom_carrier_raised,
};

static int __devinit reset_card(struct pci_dev *pdev,
const unsigned int card, unsigned int *signature)
{
Expand Down Expand Up @@ -1794,6 +1806,7 @@ static int __init isicom_init(void)
spin_lock_init(&isi_card[idx].card_lock);
for (channel = 0; channel < 16; channel++, port++) {
tty_port_init(&port->port);
port->port.ops = &isicom_port_ops;
port->magic = ISICOM_MAGIC;
port->card = &isi_card[idx];
port->channel = channel;
Expand Down
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