Enable wakeup from serial ports, make it run-time configurable over sysfs,
e.g.,
echo enabled > /sys/devices/platform/serial8250.0/tty/ttyS0/power/wakeup
Requires
# CONFIG_SYSFS_DEPRECATED is not set
Signed-off-by: Guennadi Liakhovetski <[email protected]>
---
Following suggestions from Alan and Russell moved the may_wake_up checks
to serial_core.c. This time actually tested - it does even work. Could
someone, please, verify, that put_device after device_find_child is
correct? Also would be nice to test with a Natsemi UART, that can wake up
the system, if such systems exist.
Thanks
Guennadi
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 9c57486..8a3d6ea 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1934,9 +1934,24 @@ static void uart_change_pm(struct uart_state *state, int pm_state)
}
}
+struct uart_match {
+ struct uart_port *port;
+ struct uart_driver *driver;
+};
+
+static int serial_match_port(struct device *dev, void *data)
+{
+ struct uart_match *match = data;
+ dev_t devt = MKDEV(match->driver->major, match->driver->minor) + match->port->line;
+
+ return dev->devt == devt; /* Actually, only one tty per port */
+}
+
int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
{
struct uart_state *state = drv->state + port->line;
+ struct device *tty_dev;
+ struct uart_match match = {port, drv};
mutex_lock(&state->mutex);
@@ -1947,6 +1962,15 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
}
#endif
+ tty_dev = device_find_child(port->dev, &match, serial_match_port);
+ if (device_may_wakeup(tty_dev)) {
+ enable_irq_wake(port->irq);
+ put_device(tty_dev);
+ mutex_unlock(&state->mutex);
+ return 0;
+ }
+ port->suspended = 1;
+
if (state->info && state->info->flags & UIF_INITIALIZED) {
const struct uart_ops *ops = port->ops;
@@ -1995,6 +2019,13 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
}
#endif
+ if (!port->suspended) {
+ disable_irq_wake(port->irq);
+ mutex_unlock(&state->mutex);
+ return 0;
+ }
+ port->suspended = 0;
+
uart_change_pm(state, 0);
/*
@@ -2266,6 +2297,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
{
struct uart_state *state;
int ret = 0;
+ struct device *tty_dev;
BUG_ON(in_interrupt());
@@ -2301,7 +2333,13 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
* Register the port whether it's detected or not. This allows
* setserial to be used to alter this ports parameters.
*/
- tty_register_device(drv->tty_driver, port->line, port->dev);
+ tty_dev = tty_register_device(drv->tty_driver, port->line, port->dev);
+ if (likely(!IS_ERR(tty_dev))) {
+ device_can_wakeup(tty_dev) = 1;
+ device_set_wakeup_enable(tty_dev, 0);
+ } else
+ printk(KERN_ERR "Cannot register tty device on line %d\n",
+ port->line);
/*
* If this driver supports console, and it hasn't been
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 773d8d8..60dedc0 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -291,7 +291,8 @@ struct uart_port {
unsigned long mapbase; /* for ioremap */
struct device *dev; /* parent device */
unsigned char hub6; /* this should be in the 8250 driver */
- unsigned char unused[3];
+ unsigned char suspended;
+ unsigned char unused[2];
void *private_data; /* generic platform data pointer */
};
Guennadi Liakhovetski wrote:
> Enable wakeup from serial ports, make it run-time configurable over sysfs,
> e.g.,
>
> echo enabled > /sys/devices/platform/serial8250.0/tty/ttyS0/power/wakeup
Interesting, but how does that work from a user's/hardware perspective?
Do I have to pull DSR/RI to +12V? Can I use one of the other pins to get
these +12V (i.e. a switch and a resistor to shorten these pins is
enough)?
And probably in the BIOS I have to enable "wake on modem ring" (or
something similar)?
Regards...
Michael
On Wed, 12 Sep 2007 20:50:10 +0200 (CEST)
Guennadi Liakhovetski <[email protected]> wrote:
> Enable wakeup from serial ports, make it run-time configurable over sysfs,
> e.g.,
>
> echo enabled > /sys/devices/platform/serial8250.0/tty/ttyS0/power/wakeup
>
> Requires
>
> # CONFIG_SYSFS_DEPRECATED is not set
>
> Signed-off-by: Guennadi Liakhovetski <[email protected]>
>
> ---
>
> Following suggestions from Alan and Russell moved the may_wake_up checks
> to serial_core.c. This time actually tested - it does even work. Could
> someone, please, verify, that put_device after device_find_child is
> correct?
Seems right to me, from reading device_find_child() and its associated
documentation.
> Also would be nice to test with a Natsemi UART, that can wake up
> the system, if such systems exist.
>
It would help if you could provide simple-to-follow steps which a tester
should follow to perform this testing.
>
> diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
> index 9c57486..8a3d6ea 100644
> --- a/drivers/serial/serial_core.c
> +++ b/drivers/serial/serial_core.c
> @@ -1934,9 +1934,24 @@ static void uart_change_pm(struct uart_state *state, int pm_state)
> }
> }
>
> +struct uart_match {
> + struct uart_port *port;
> + struct uart_driver *driver;
> +};
> +
> +static int serial_match_port(struct device *dev, void *data)
> +{
> + struct uart_match *match = data;
> + dev_t devt = MKDEV(match->driver->major, match->driver->minor) + match->port->line;
> +
> + return dev->devt == devt; /* Actually, only one tty per port */
> +}
> +
> int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
> {
> struct uart_state *state = drv->state + port->line;
> + struct device *tty_dev;
> + struct uart_match match = {port, drv};
>
> mutex_lock(&state->mutex);
>
> @@ -1947,6 +1962,15 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
> }
> #endif
>
> + tty_dev = device_find_child(port->dev, &match, serial_match_port);
> + if (device_may_wakeup(tty_dev)) {
> + enable_irq_wake(port->irq);
> + put_device(tty_dev);
> + mutex_unlock(&state->mutex);
> + return 0;
> + }
> + port->suspended = 1;
> +
> if (state->info && state->info->flags & UIF_INITIALIZED) {
> const struct uart_ops *ops = port->ops;
>
> @@ -1995,6 +2019,13 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
> }
> #endif
>
> + if (!port->suspended) {
> + disable_irq_wake(port->irq);
> + mutex_unlock(&state->mutex);
> + return 0;
> + }
> + port->suspended = 0;
> +
> uart_change_pm(state, 0);
>
> /*
> @@ -2266,6 +2297,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
> {
> struct uart_state *state;
> int ret = 0;
> + struct device *tty_dev;
>
> BUG_ON(in_interrupt());
>
> @@ -2301,7 +2333,13 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
> * Register the port whether it's detected or not. This allows
> * setserial to be used to alter this ports parameters.
> */
> - tty_register_device(drv->tty_driver, port->line, port->dev);
> + tty_dev = tty_register_device(drv->tty_driver, port->line, port->dev);
> + if (likely(!IS_ERR(tty_dev))) {
> + device_can_wakeup(tty_dev) = 1;
> + device_set_wakeup_enable(tty_dev, 0);
> + } else
> + printk(KERN_ERR "Cannot register tty device on line %d\n",
> + port->line);
>
> /*
> * If this driver supports console, and it hasn't been
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index 773d8d8..60dedc0 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -291,7 +291,8 @@ struct uart_port {
> unsigned long mapbase; /* for ioremap */
> struct device *dev; /* parent device */
> unsigned char hub6; /* this should be in the 8250 driver */
> - unsigned char unused[3];
> + unsigned char suspended;
> + unsigned char unused[2];
> void *private_data; /* generic platform data pointer */
> };
>
On Wed, 12 Sep 2007, Michael Mauch wrote:
> Guennadi Liakhovetski wrote:
>
> > Enable wakeup from serial ports, make it run-time configurable over sysfs,
> > e.g.,
> >
> > echo enabled > /sys/devices/platform/serial8250.0/tty/ttyS0/power/wakeup
>
> Interesting, but how does that work from a user's/hardware perspective?
>
> Do I have to pull DSR/RI to +12V? Can I use one of the other pins to get
> these +12V (i.e. a switch and a resistor to shorten these pins is
> enough)?
>
> And probably in the BIOS I have to enable "wake on modem ring" (or
> something similar)?
It depends on the hardware. In principle, with this patch _if_ your system
can suspend while keeping the UART powered on and the interrupt from this
UART can wake up your system, then using this patch and the command above
you'll be able to also keep the UART configured, i.e., prevent the driver
from suspending it during suspend and then an interrupt from this UART
will wake up the system. How you generate this interrupt - doesn't matter.
Whether it is a received byte, or a modem line toggle, as long as it
produces an interrupt, the system will wake up.
Don't know whether "normal" PCs can do that and if yes - how.
Thanks
Guennadi
---
Guennadi Liakhovetski
On Wed, Sep 12, 2007 at 03:36:10PM -0700, Andrew Morton wrote:
> On Wed, 12 Sep 2007 20:50:10 +0200 (CEST)
> Guennadi Liakhovetski <[email protected]> wrote:
>
> > Enable wakeup from serial ports, make it run-time configurable over sysfs,
> > e.g.,
> >
> > echo enabled > /sys/devices/platform/serial8250.0/tty/ttyS0/power/wakeup
> >
> > Requires
> >
> > # CONFIG_SYSFS_DEPRECATED is not set
> >
> > Signed-off-by: Guennadi Liakhovetski <[email protected]>
> >
> > ---
> >
> > Following suggestions from Alan and Russell moved the may_wake_up checks
> > to serial_core.c. This time actually tested - it does even work. Could
> > someone, please, verify, that put_device after device_find_child is
> > correct?
>
> Seems right to me, from reading device_find_child() and its associated
> documentation.
Yes, that is correct.
thanks,
greg k-h
On Wed, 12 Sep 2007, Andrew Morton wrote:
> On Wed, 12 Sep 2007 20:50:10 +0200 (CEST)
> Guennadi Liakhovetski <[email protected]> wrote:
>
> > Enable wakeup from serial ports, make it run-time configurable over sysfs,
> > e.g.,
> >
> > echo enabled > /sys/devices/platform/serial8250.0/tty/ttyS0/power/wakeup
> >
> > Requires
> >
> > # CONFIG_SYSFS_DEPRECATED is not set
> >
> > Signed-off-by: Guennadi Liakhovetski <[email protected]>
> >
> > ---
[snip]
> > Also would be nice to test with a Natsemi UART, that can wake up
> > the system, if such systems exist.
>
> It would help if you could provide simple-to-follow steps which a tester
> should follow to perform this testing.
Ok, for anyone owning a system with a Natsemi UART and capable to suspend
and resume it (you do not have to be able to resume it from the UART),
would be great to have the patch below tested. For this you just have to
apply the patch below, issue the above "echo" command to one of your
Natsemi port, suspend and resume your system, and verify that your Natsemi
port still works. If you are actually capable of waking up the system from
that port, would be nice to test that as well.
Thanks
Guennadi
> > diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
> > index 9c57486..8a3d6ea 100644
> > --- a/drivers/serial/serial_core.c
> > +++ b/drivers/serial/serial_core.c
> > @@ -1934,9 +1934,24 @@ static void uart_change_pm(struct uart_state *state, int pm_state)
> > }
> > }
> >
> > +struct uart_match {
> > + struct uart_port *port;
> > + struct uart_driver *driver;
> > +};
> > +
> > +static int serial_match_port(struct device *dev, void *data)
> > +{
> > + struct uart_match *match = data;
> > + dev_t devt = MKDEV(match->driver->major, match->driver->minor) + match->port->line;
> > +
> > + return dev->devt == devt; /* Actually, only one tty per port */
> > +}
> > +
> > int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
> > {
> > struct uart_state *state = drv->state + port->line;
> > + struct device *tty_dev;
> > + struct uart_match match = {port, drv};
> >
> > mutex_lock(&state->mutex);
> >
> > @@ -1947,6 +1962,15 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
> > }
> > #endif
> >
> > + tty_dev = device_find_child(port->dev, &match, serial_match_port);
> > + if (device_may_wakeup(tty_dev)) {
> > + enable_irq_wake(port->irq);
> > + put_device(tty_dev);
> > + mutex_unlock(&state->mutex);
> > + return 0;
> > + }
> > + port->suspended = 1;
> > +
> > if (state->info && state->info->flags & UIF_INITIALIZED) {
> > const struct uart_ops *ops = port->ops;
> >
> > @@ -1995,6 +2019,13 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
> > }
> > #endif
> >
> > + if (!port->suspended) {
> > + disable_irq_wake(port->irq);
> > + mutex_unlock(&state->mutex);
> > + return 0;
> > + }
> > + port->suspended = 0;
> > +
> > uart_change_pm(state, 0);
> >
> > /*
> > @@ -2266,6 +2297,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
> > {
> > struct uart_state *state;
> > int ret = 0;
> > + struct device *tty_dev;
> >
> > BUG_ON(in_interrupt());
> >
> > @@ -2301,7 +2333,13 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
> > * Register the port whether it's detected or not. This allows
> > * setserial to be used to alter this ports parameters.
> > */
> > - tty_register_device(drv->tty_driver, port->line, port->dev);
> > + tty_dev = tty_register_device(drv->tty_driver, port->line, port->dev);
> > + if (likely(!IS_ERR(tty_dev))) {
> > + device_can_wakeup(tty_dev) = 1;
> > + device_set_wakeup_enable(tty_dev, 0);
> > + } else
> > + printk(KERN_ERR "Cannot register tty device on line %d\n",
> > + port->line);
> >
> > /*
> > * If this driver supports console, and it hasn't been
> > diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> > index 773d8d8..60dedc0 100644
> > --- a/include/linux/serial_core.h
> > +++ b/include/linux/serial_core.h
> > @@ -291,7 +291,8 @@ struct uart_port {
> > unsigned long mapbase; /* for ioremap */
> > struct device *dev; /* parent device */
> > unsigned char hub6; /* this should be in the 8250 driver */
> > - unsigned char unused[3];
> > + unsigned char suspended;
> > + unsigned char unused[2];
> > void *private_data; /* generic platform data pointer */
> > };
> >
>
---
Guennadi Liakhovetski