linux-stable.git/drivers/tty/serdev/core.c, branch linux-5.4.y

serdev: Don't claim unsupported ACPI serial devices

2020-01-14T19:08:32+00:00

commit c5ee0b3104e0b292d353e63fd31cb8c692645d8c upstream.

Serdev sub-system claims all ACPI serial devices that are not already
initialised. As a result, no device node is created for serial ports
on certain boards such as the Apollo Lake based UP2. This has the
unintended consequence of not being able to raise the login prompt via
serial connection.

Introduce a blacklist to reject ACPI serial devices that should not be
claimed by serdev sub-system. Add the peripheral ids for Intel HS UART
to the blacklist to bring back serial port on SoCs carrying them.

Cc: stable@vger.kernel.org
Signed-off-by: Punit Agrawal 
Acked-by: Hans de Goede 
Acked-by: Johan Hovold 
Cc: Rob Herring 
Link: https://lore.kernel.org/r/20191219100345.911093-1-punit1.agrawal@toshiba.co.jp
Signed-off-by: Greg Kroah-Hartman

serdev: document the write functions using kernel-doc

2018-11-27T18:44:21+00:00

Document the asynchronous serdev_device_write_buf() and synchronous
serdev_device_write() functions using kernel-doc.

Specifically, mention that writing data only means that data has been
buffered by the controller, and that the synchronous helper depends on
serdev_device_write_wakeup() being called in the driver write_wakeup()
callback.

Signed-off-by: Johan Hovold 
Reviewed-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman

serdev: make synchronous write helper interruptible

2018-11-27T18:44:21+00:00

Allow the synchronous serdev_device_write() helper to be interrupted.

This is useful for cases where I/O is performed on behalf of user space
and we don't want to block indefinitely when using flow control.

Signed-off-by: Johan Hovold 
Reviewed-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman

serdev: make synchronous write return bytes written

2018-11-27T18:44:21+00:00

Make the synchronous serdev_device_write() helper behave analogous to
the asynchronous serdev_device_write_buf() by returning the number of
bytes written (or rather buffered) also on timeout.

This will allow drivers to distinguish the case where data was partially
written from the case where no data was written.

Also update the only two users that checked the return value.

Signed-off-by: Johan Hovold 
Reviewed-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman

serdev: use zero to indicate infinite write timeout

2018-11-27T18:44:21+00:00

Use zero to indicate infinite timeout for the synchronous
serdev_device_write() helper.

This allows drivers to specify an infinite timeout without knowing about
serdev implementation details, while also allowing the same timeout
argument to be used for both serdev_device_write() and
serdev_device_wait_until_sent().

Note that passing zero to the current helper makes no sense; just call
the asynchronous serdev_device_write_buf() directly instead.

Signed-off-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman

serdev: add dev_pm_domain_attach|detach()

2018-07-15T10:23:53+00:00

In order to open up the required power gate before any operation can be
effectively performed over the serial bus between CPU and serdev, it's
clearly essential to add common attach functions for PM domains to serdev
at the probe phase.

Similarly, the relevant dettach function for the PM domains should be
properly and reversely added at the remove phase.

Signed-off-by: Sean Wang 
Reviewed-by: Ulf Hansson 
Reviewed-by: Johan Hovold 
Cc: Rob Herring 
Cc: Ulf Hansson 
Cc: Jiri Slaby 
Cc: linux-serial@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

Merge 4.18-rc3 into tty-next

2018-07-02T06:23:43+00:00

We want ths tty core changes in here as well.

Signed-off-by: Greg Kroah-Hartman

serdev: fix memleak on module unload

2018-06-28T12:34:39+00:00

Make sure to free all resources associated with the ida on module
exit.

Fixes: cd6484e1830b ("serdev: Introduce new bus for serial attached devices")
Cc: stable 	# 4.11
Signed-off-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman

serdev: add controller runtime PM support

2018-06-28T12:07:54+00:00

Add support for controller runtime power management to serdev core. This
is needed to allow slave drivers to manage the runtime PM state of the
underlying serial controller when its driver, in turn, implements more
aggressive runtime power management (e.g. using autosuspend).

For some applications, for example, where loss off initial data after a
remote-wakeup event is acceptable or where rx is not used at all,
aggressive serial controller runtime PM may be used without further
involvement of the slave driver. But when this is not the case, the
slave driver must be able to indicate when incoming data is expected in
order to avoid data loss.

To facilitate the common case, where the serial controller power state
is active whenever the port is open (which is the case with just about
every serial driver), and where data loss is not acceptable and cannot
even be prevented by explicit controller runtime power management, an
RPM reference is taken in serdev open and put again at close. This
reference can later be balanced by any serdev driver which wants and/or
can handle aggressive controller runtime PM.

Note that the .ignore_children flag is set for the serdev controller to
allow the underlying hardware to idle when no I/O is expected, regardless
of the slave device RPM state.

Acked-by: Tony Lindgren 
Reviewed-by: Sebastian Reichel 
Signed-off-by: Johan Hovold 
Acked-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman

serdev: Fix typo in serdev_device_alloc

2018-03-14T14:02:45+00:00

Fix function name in serdev_device_alloc() definition

Signed-off-by: Frédéric Danis 
Signed-off-by: Greg Kroah-Hartman