[PATCH 00/11] Sort out sdio_uart - stage two

Move the HUCPL handling from the end of close_port_start to the beginning
of close_port_end. What this actually does is change the ordering from

port shutdown
port->dtr_rts

to

port->dtr_rts
port shutdown

Some hardware drops the physical connection on shutdown so we must perform
the port operations before the shutdown.

Signed-off-by: Alan Cox <alan.DeleteThis@linux.intel.com>
---

drivers/char/tty_port.c | 13 ++++++++-----
1 files changed, 8 insertions(+), 5 deletions(-)


diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index da12fae..cf4b16a 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -357,6 +357,14 @@ int tty_port_close_start(struct tty_port *port,
timeout = 2 * HZ;
schedule_timeout_interruptible(timeout);
}
+ /* Flush the ldisc buffering */
+ tty_ldisc_flush(tty);
+
+ /* Drop DTR/RTS if HUPCL is set. This causes any attached modem to
+ hang up the line */
+ if (tty->termios->c_cflag & HUPCL)
+ tty_port_lower_dtr_rts(port);
+
/* Don't call port->drop for the last reference. Callers will want
to drop the last active reference in ->shutdown() or the tty
shutdown path */
@@ -368,11 +376,6 @@ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
{
unsigned long flags;

- tty_ldisc_flush(tty);
-
- if (tty->termios->c_cflag & HUPCL)
- tty_port_lower_dtr_rts(port);
-
spin_lock_irqsave(&port->lock, flags);
tty->closing = 0;


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Add a tty_port object to the sdio uart. For the moment just begin using the
tty field of the port, as this is the critical one to clean up.

Signed-off-by: Alan Cox <alan DeleteThis @linux.intel.com>
---

drivers/mmc/card/sdio_uart.c | 41 +++++++++++++++++++++++------------------
1 files changed, 23 insertions(+), 18 deletions(-)


diff --git a/drivers/mmc/card/sdio_uart.c b/drivers/mmc/card/sdio_uart.c
index b8e7c5a..c2759db 100644
--- a/drivers/mmc/card/sdio_uart.c
+++ b/drivers/mmc/card/sdio_uart.c
@@ -73,6 +73,7 @@ struct uart_icount {
};

struct sdio_uart_port {
+ struct tty_port port;
struct kref kref;
struct tty_struct *tty;
unsigned int index;
@@ -172,7 +173,7 @@ static void sdio_uart_port_remove(struct sdio_uart_port *port)
port->func = NULL;
mutex_unlock(&port->func_lock);
if (port->opened)
- tty_hangup(port->tty);
+ tty_hangup(port->port.tty);
mutex_unlock(&port->open_lock);
sdio_release_irq(func);
sdio_disable_func(func);
@@ -391,7 +392,7 @@ static void sdio_uart_stop_rx(struct sdio_uart_port *port)
static void sdio_uart_receive_chars(struct sdio_uart_port *port,
unsigned int *status)
{
- struct tty_struct *tty = port->tty;
+ struct tty_struct *tty = port->port.tty;
unsigned int ch, flag;
int max_count = 256;

@@ -446,6 +447,7 @@ static void sdio_uart_transmit_chars(struct sdio_uart_port *port)
{
struct circ_buf *xmit = &port->xmit;
int count;
+ struct tty_struct *tty = port->port.tty;

if (port->x_char) {
sdio_out(port, UART_TX, port->x_char);
@@ -453,7 +455,7 @@ static void sdio_uart_transmit_chars(struct sdio_uart_port *port)
port->x_char = 0;
return;
}
- if (circ_empty(xmit) || port->tty->stopped || port->tty->hw_stopped) {
+ if (circ_empty(xmit) || tty->stopped || tty->hw_stopped) {
sdio_uart_stop_tx(port);
return;
}
@@ -468,7 +470,7 @@ static void sdio_uart_transmit_chars(struct sdio_uart_port *port)
} while (--count > 0);

if (circ_chars_pending(xmit) < WAKEUP_CHARS)
- tty_wakeup(port->tty);
+ tty_wakeup(tty);

if (circ_empty(xmit))
sdio_uart_stop_tx(port);
@@ -477,6 +479,7 @@ static void sdio_uart_transmit_chars(struct sdio_uart_port *port)
static void sdio_uart_check_modem_status(struct sdio_uart_port *port)
{
int status;
+ struct tty_struct *tty = port->port.tty;

status = sdio_in(port, UART_MSR);

@@ -491,17 +494,17 @@ static void sdio_uart_check_modem_status(struct sdio_uart_port *port)
port->icount.dcd++;
if (status & UART_MSR_DCTS) {
port->icount.cts++;
- if (port->tty->termios->c_cflag & CRTSCTS) {
+ if (tty->termios->c_cflag & CRTSCTS) {
int cts = (status & UART_MSR_CTS);
- if (port->tty->hw_stopped) {
+ if (tty->hw_stopped) {
if (cts) {
- port->tty->hw_stopped = 0;
+ tty->hw_stopped = 0;
sdio_uart_start_tx(port);
- tty_wakeup(port->tty);
+ tty_wakeup(tty);
}
} else {
if (!cts) {
- port->tty->hw_stopped = 1;
+ tty->hw_stopped = 1;
sdio_uart_stop_tx(port);
}
}
@@ -546,12 +549,13 @@ static int sdio_uart_startup(struct sdio_uart_port *port)
{
unsigned long page;
int ret;
+ struct tty_struct *tty = port->port.tty;

/*
* Set the TTY IO error marker - we will only clear this
* once we have successfully opened the port.
*/
- set_bit(TTY_IO_ERROR, &port->tty->flags);
+ set_bit(TTY_IO_ERROR, &tty->flags);

/* Initialise and allocate the transmit buffer. */
page = __get_free_page(GFP_KERNEL);
@@ -595,14 +599,14 @@ static int sdio_uart_startup(struct sdio_uart_port *port)
port->ier = UART_IER_RLSI | UART_IER_RDI | UART_IER_RTOIE | UART_IER_UUE;
port->mctrl = TIOCM_OUT2;

- sdio_uart_change_speed(port, port->tty->termios, NULL);
+ sdio_uart_change_speed(port, tty->termios, NULL);

- if (port->tty->termios->c_cflag & CBAUD)
+ if (tty->termios->c_cflag & CBAUD)
sdio_uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);

- if (port->tty->termios->c_cflag & CRTSCTS)
+ if (tty->termios->c_cflag & CRTSCTS)
if (!(sdio_uart_get_mctrl(port) & TIOCM_CTS))
- port->tty->hw_stopped = 1;
+ tty->hw_stopped = 1;

clear_bit(TTY_IO_ERROR, &port->tty->flags);

@@ -634,7 +638,7 @@ static void sdio_uart_shutdown(struct sdio_uart_port *port)
/* TODO: wait here for TX FIFO to drain */

/* Turn off DTR and RTS early. */
- if (port->tty->termios->c_cflag & HUPCL)
+ if (port->port.tty->termios->c_cflag & HUPCL)
sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);

/* Disable interrupts from this port */
@@ -684,11 +688,11 @@ static int sdio_uart_open(struct tty_struct *tty, struct file *filp)

if (!port->opened) {
tty->driver_data = port;
- port->tty = tty;
+ port->port.tty = tty;
ret = sdio_uart_startup(port);
if (ret) {
tty->driver_data = NULL;
- port->tty = NULL;
+ port->port.tty = NULL;
mutex_unlock(&port->open_lock);
sdio_uart_port_put(port);
return ret;
@@ -723,7 +727,7 @@ static void sdio_uart_close(struct tty_struct *tty, struct file * filp)
tty->closing = 1;
sdio_uart_shutdown(port);
tty_ldisc_flush(tty);
- port->tty = NULL;
+ port->port.tty = NULL;
tty->driver_data = NULL;
tty->closing = 0;
}
@@ -1068,6 +1072,7 @@ static int sdio_uart_probe(struct sdio_func *func,

port->func = func;
sdio_set_drvdata(func, port);
+ tty_port_init(&port->port);

ret = sdio_uart_add_port(port);
if (ret) {

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On Tue, 3 Nov 2009, Alan Cox wrote:

> With the bugs Nicolas reported hopefully now nailed.

Progress, but still not there yet.

I'm still using the same "cat /dev/ttySDIO0" test with a GPS card.

Yanking the card out does terminate the cat process properly. Inserting
the card back in and restarting cat always fails with:

cat: /dev/ttySDIO0: Input/output error

The same thing occurs if I terminate cat with ^C instead of pulling the
card out.

From what I can see, sdio_uart_open() and sdio_uart_activate() are
called on the first cat invocation, and then sdio_uart_close() and
sdio_uart_shutdown() when cat is stopped with ^C. However neither
sdio_uart_open() nor sdio_uart_activate() is ever called anymore with
any subsequent cat invocations until a reboot. Some upper layer must
have taken upon itself to return -EIO to user space.


Nicolas
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> >From what I can see, sdio_uart_open() and sdio_uart_activate() are
> called on the first cat invocation, and then sdio_uart_close() and
> sdio_uart_shutdown() when cat is stopped with ^C. However neither

I would have expected the cat to terminate when the port is unplugged
(and the uart remove method called - doing a hangup)

> sdio_uart_open() nor sdio_uart_activate() is ever called anymore with
> any subsequent cat invocations until a reboot. Some upper layer must
> have taken upon itself to return -EIO to user space.

The first call into the driver is to sdio_uart_install which looks up the
port from tty->index and would blow up if for some reason the get method
failed.

Still digging.
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On Wed, 4 Nov 2009, Alan Cox wrote:

> > >From what I can see, sdio_uart_open() and sdio_uart_activate() are
> > called on the first cat invocation, and then sdio_uart_close() and
> > sdio_uart_shutdown() when cat is stopped with ^C. However neither
>
> I would have expected the cat to terminate when the port is unplugged
> (and the uart remove method called - doing a hangup)

That works fine... the first time only. After the card is inserted back
then -EIO is always returned on open() from user space, same thing as
subsequent open() after ^C.

> > sdio_uart_open() nor sdio_uart_activate() is ever called anymore with
> > any subsequent cat invocations until a reboot. Some upper layer must
> > have taken upon itself to return -EIO to user space.
>
> The first call into the driver is to sdio_uart_install which looks up the
> port from tty->index and would blow up if for some reason the get method
> failed.

Well, same issue: I see it being called the first time. No calls what
so ever afterward until the next reboot.


Nicolas
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