linux-toradex.git/drivers/tty/hvc, branch v6.7

Merge tag 'tty-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2023-11-04T01:44:25+00:00

Pull tty and serial updates from Greg KH:
 "Here is the big set of tty/serial driver changes for 6.7-rc1. Included
  in here are:

   - console/vgacon cleanups and removals from Arnd

   - tty core and n_tty cleanups from Jiri

   - lots of 8250 driver updates and cleanups

   - sc16is7xx serial driver updates

   - dt binding updates

   - first set of port lock wrapers from Thomas for the printk fixes
     coming in future releases

   - other small serial and tty core cleanups and updates

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (193 commits)
  serdev: Replace custom code with device_match_acpi_handle()
  serdev: Simplify devm_serdev_device_open() function
  serdev: Make use of device_set_node()
  tty: n_gsm: add copyright Siemens Mobility GmbH
  tty: n_gsm: fix race condition in status line change on dead connections
  serial: core: Fix runtime PM handling for pending tx
  vgacon: fix mips/sibyte build regression
  dt-bindings: serial: drop unsupported samsung bindings
  tty: serial: samsung: drop earlycon support for unsupported platforms
  tty: 8250: Add note for PX-835
  tty: 8250: Fix IS-200 PCI ID comment
  tty: 8250: Add Brainboxes Oxford Semiconductor-based quirks
  tty: 8250: Add support for Intashield IX cards
  tty: 8250: Add support for additional Brainboxes PX cards
  tty: 8250: Fix up PX-803/PX-857
  tty: 8250: Fix port count of PX-257
  tty: 8250: Add support for Intashield IS-100
  tty: 8250: Add support for Brainboxes UP cards
  tty: 8250: Add support for additional Brainboxes UC cards
  tty: 8250: Remove UC-257 and UC-431
  ...

hvc/xen: fix console unplug

2023-10-21T16:33:02+00:00

On unplug of a Xen console, xencons_disconnect_backend() unconditionally
calls free_irq() via unbind_from_irqhandler(), causing a warning of
freeing an already-free IRQ:

(qemu) device_del con1
[   32.050919] ------------[ cut here ]------------
[   32.050942] Trying to free already-free IRQ 33
[   32.050990] WARNING: CPU: 0 PID: 51 at kernel/irq/manage.c:1895 __free_irq+0x1d4/0x330

It should be using evtchn_put() to tear down the event channel binding,
and let the Linux IRQ side of it be handled by notifier_del_irq() through
the HVC code.

On which topic... xencons_disconnect_backend() should call hvc_remove()
*first*, rather than tearing down the event channel and grant mapping
while they are in use. And then the IRQ is guaranteed to be freed by
the time it's torn down by evtchn_put().

Since evtchn_put() also closes the actual event channel, avoid calling
xenbus_free_evtchn() except in the failure path where the IRQ was not
successfully set up.

However, calling hvc_remove() at the start of xencons_disconnect_backend()
still isn't early enough. An unplug request is indicated by the backend
setting its state to XenbusStateClosing, which triggers a notification
to xencons_backend_changed(), which... does nothing except set its own
frontend state directly to XenbusStateClosed without *actually* tearing
down the HVC device or, you know, making sure it isn't actively in use.

So the backend sees the guest frontend set its state to XenbusStateClosed
and stops servicing the interrupt... and the guest spins for ever in the
domU_write_console() function waiting for the ring to drain.

Fix that one by calling hvc_remove() from xencons_backend_changed() before
signalling to the backend that it's OK to proceed with the removal.

Tested with 'dd if=/dev/zero of=/dev/hvc1' while telling Qemu to remove
the console device.

Signed-off-by: David Woodhouse 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231020161529.355083-4-dwmw2@infradead.org
Signed-off-by: Greg Kroah-Hartman

hvc/xen: fix error path in xen_hvc_init() to always register frontend driver

2023-10-21T16:33:02+00:00

The xen_hvc_init() function should always register the frontend driver,
even when there's no primary console — as there may be secondary consoles.
(Qemu can always add secondary consoles, but only the toolstack can add
the primary because it's special.)

Signed-off-by: David Woodhouse 
Reviewed-by: Juergen Gross 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231020161529.355083-3-dwmw2@infradead.org
Signed-off-by: Greg Kroah-Hartman

hvc/xen: fix event channel handling for secondary consoles

2023-10-21T16:32:57+00:00

The xencons_connect_backend() function allocates a local interdomain
event channel with xenbus_alloc_evtchn(), then calls
bind_interdomain_evtchn_to_irq_lateeoi() to bind to that port# on the
*remote* domain.

That doesn't work very well:

(qemu) device_add xen-console,id=con1,chardev=pty0
[   44.323872] xenconsole console-1: 2 xenbus_dev_probe on device/console/1
[   44.323995] xenconsole: probe of console-1 failed with error -2

Fix it to use bind_evtchn_to_irq_lateeoi(), which does the right thing
by just binding that *local* event channel to an irq. The backend will
do the interdomain binding.

This didn't affect the primary console because the setup for that is
special — the toolstack allocates the guest event channel and the guest
discovers it with HVMOP_get_param.

Fixes: fe415186b43d ("xen/console: harden hvc_xen against event channel storms")
Signed-off-by: David Woodhouse 
Reviewed-by: Juergen Gross 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231020161529.355083-2-dwmw2@infradead.org
Signed-off-by: Greg Kroah-Hartman

docs: move powerpc under arch

2023-10-10T19:35:55+00:00

and fix all in-tree references.

Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy.

Signed-off-by: Costa Shulyupin 
Acked-by: Michael Ellerman 
Signed-off-by: Jonathan Corbet 
Link: https://lore.kernel.org/r/20230826165737.2101199-1-costa.shul@redhat.com

tty: hvc: remove set but unused variable

2023-09-18T09:14:42+00:00

The local variable vdev in hvcs_destruct_port() is set
but not used. Remove the variable and related code.

Signed-off-by: Bo Liu 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20230908061726.2641-1-liubo03@inspur.com
Signed-off-by: Greg Kroah-Hartman

tty: hvc: convert counts to size_t

2023-08-11T19:12:47+00:00

Unify the type of tty_operations::write() counters with the 'count'
parameter. I.e. use size_t for them.

Signed-off-by: "Jiri Slaby (SUSE)" 
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230810091510.13006-33-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: make tty_operations::write()'s count size_t

2023-08-11T19:12:46+00:00

Unify with the rest of the code. Use size_t for counts and ssize_t for
retval.

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230810091510.13006-30-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: propagate u8 data to tty_operations::write()

2023-08-11T19:12:46+00:00

Data are now typed as u8. Propagate this change to
tty_operations::write().

Signed-off-by: "Jiri Slaby (SUSE)" 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Geert Uytterhoeven 
Cc: Richard Weinberger 
Cc: Anton Ivanov 
Cc: Johannes Berg 
Cc: Chris Zankel 
Cc: Max Filippov 
Cc: Arnd Bergmann 
Cc: Vaibhav Gupta 
Cc: Jens Taprogge 
Cc: Karsten Keil 
Cc: Scott Branden 
Cc: Ulf Hansson 
Cc: "David S. Miller" 
Cc: Eric Dumazet 
Cc: Jakub Kicinski 
Cc: Paolo Abeni 
Cc: Heiko Carstens 
Cc: Vasily Gorbik 
Cc: Alexander Gordeev 
Cc: Christian Borntraeger 
Cc: Sven Schnelle 
Cc: David Lin 
Cc: Johan Hovold 
Cc: Alex Elder 
Cc: Laurentiu Tudor 
Cc: Jiri Kosina 
Cc: David Sterba 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Pengutronix Kernel Team 
Cc: Fabio Estevam 
Cc: NXP Linux Team 
Cc: Arnaud Pouliquen 
Cc: Oliver Neukum 
Cc: Mathias Nyman 
Cc: Marcel Holtmann 
Cc: Johan Hedberg 
Cc: Luiz Augusto von Dentz 
Link: https://lore.kernel.org/r/20230810091510.13006-28-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: hvsi: remove an extra variable from hvsi_write()

2023-07-31T15:16:05+00:00

'source' is the same as 'buf'. Rename the parameter ('buf') to
'source' and drop the local variable.

Likely, the two were introduced to have a different type. But 'char' and
'unsigned char' are the same in the kernel for a long time.

Signed-off-by: Jiri Slaby (SUSE) 
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230731080244.2698-4-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman