linux.git/drivers/tty/serial/serial_core.c, branch v6.5

serial: core: Fix error handling for serial_core_ctrl_device_add()

2023-06-02T07:30:55+00:00

Checking for NULL is incorrect as serial_base_ctrl_add() uses ERR_PTR().

Let's also pass any returned error along, there's no reason to translate
all errors to -ENODEV.

Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Tony Lindgren 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20230602070007.59268-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman

serial: core: Don't drop port_mutex in serial_core_remove_one_port

2023-06-01T13:04:01+00:00

Commit 84a9582fd203 ("serial: core: Start managing serial controllers to
enable runtime PM") required the caller to hold port_mutex rather than
taking it locally. However the mutex_unlock() call wasn't removed
causing the mutex to be dropped unexpectly. Remove the call to
mutex_unlock() (and fix up the early return) to restore correct
behaviour.

Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Steven Price 
Reviewed-by: Tony Lindgren 
Link: https://lore.kernel.org/r/20230601105548.29965-1-steven.price@arm.com
Signed-off-by: Greg Kroah-Hartman

serial: core: Start managing serial controllers to enable runtime PM

2023-05-31T09:46:59+00:00

We want to enable runtime PM for serial port device drivers in a generic
way. To do this, we want to have the serial core layer manage the
registered physical serial controller devices.

To manage serial controllers, let's set up a struct bus and struct device
for the serial core controller as suggested by Greg and Jiri. The serial
core controller devices are children of the physical serial port device.
The serial core controller device is needed to support multiple different
kind of ports connected to single physical serial port device.

Let's also set up a struct device for the serial core port. The serial
core port instances are children of the serial core controller device.

With the serial core port device we can now flush pending TX on the
runtime PM resume as suggested by Johan.

Suggested-by: Andy Shevchenko 
Suggested-by: Greg Kroah-Hartman 
Suggested-by: Jiri Slaby 
Suggested-by: Johan Hovold 
Signed-off-by: Tony Lindgren 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20230525113034.46880-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman

serial: core: lock port for start_rx() in uart_resume_port()

2023-05-30T10:45:42+00:00

The only user of the start_rx() callback (qcom_geni) directly calls
its own stop_rx() callback. Since stop_rx() requires that the
port->lock is taken and interrupts are disabled, the start_rx()
callback has the same requirement.

Fixes: cfab87c2c271 ("serial: core: Introduce callback for start_rx and do stop_rx in suspend only if this callback implementation is present.")
Signed-off-by: John Ogness 
Reviewed-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20230525093159.223817-5-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman

serial: core: lock port for stop_rx() in uart_suspend_port()

2023-05-30T10:45:42+00:00

The uarts_ops stop_rx() callback expects that the port->lock is
taken and interrupts are disabled.

Fixes: c9d2325cdb92 ("serial: core: Do stop_rx in suspend path for console if console_suspend is disabled")
Signed-off-by: John Ogness 
Reviewed-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20230525093159.223817-3-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman

serial: Make uart_remove_one_port() return void

2023-05-13T10:48:16+00:00

The return value is only ever used as a return value for remove callbacks
of platform drivers. This return value is ignored by the driver core.
(The only effect is an error message, but uart_remove_one_port() already
emitted one in this case.)

So the return value isn't used at all and uart_remove_one_port() can be
changed to return void without any loss. Also this better matches the
Linux device model as remove functions are not supposed to fail.

Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20230512173810.131447-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman

serial: core: Disable uart_start() on uart_remove_one_port()

2023-04-20T11:43:44+00:00

While rebinding a uart device in a loop I noticed we may see a tx related
race on uart_remove_one_port():

uart_write from n_tty_write
n_tty_write from file_tty_write.constprop.0
file_tty_write.constprop.0 from vfs_write
vfs_write from ksys_write
ksys_write from ret_fast_syscall

Let's disallow tx on port->UPF_DEAD. This flag gets set before we start
tearing down the port in uart_remove_one_port().

Signed-off-by: Tony Lindgren 
Link: https://lore.kernel.org/r/20230419115423.59957-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman

serial: fix TIOCSRS485 locking

2023-04-20T11:42:24+00:00

The RS485 multipoint addressing support for some reason added a new
ADDRB termios cflag which is (only!) updated from one of the RS485
ioctls.

Make sure to take the termios rw semaphore for the right ioctl (i.e.
set, not get).

Fixes: ae50bb275283 ("serial: take termios_rwsem for ->rs485_config() & pass termios as param")
Cc: stable@vger.kernel.org	# 6.0
Cc: Ilpo Järvinen 
Reviewed-by: Ilpo Järvinen 
Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20230412124811.11217-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: uart_poll_init() should power on the UART

2023-03-29T08:51:52+00:00

On Qualcomm devices which use the "geni" serial driver, kdb/kgdb won't
be very happy if you use it but the resources of the port haven't been
powered on. Today kdb/kgdb rely on someone else powering the port
on. This could be the normal kernel console or an agetty running.
Let's fix this to explicitly power things on when setting up a polling
driver.

Signed-off-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20230316132027.RESEND.1.I106c39498d8094c6f5e7ada42c7db17aa5c64e48@changeid
Signed-off-by: Greg Kroah-Hartman

serial: Remove uart_wait_until_sent() forward declaration

2023-03-17T14:00:40+00:00

Remove unnecessary forward declaration of uart_wait_until_sent().

Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20230309080923.11778-9-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman