linux.git/drivers/tty, branch v6.6.13

serial: 8250_omap: Add earlycon support for the AM654 UART controller

2023-12-13T17:45:33+00:00

commit 8e42c301ce64e0dcca547626eb486877d502d336 upstream.

Currently there is no support for earlycon on the AM654 UART
controller. This commit adds it.

Signed-off-by: Ronald Wahl 
Reviewed-by: Vignesh Raghavendra 
Link: https://lore.kernel.org/r/20231031131242.15516-1-rwahl@gmx.de
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

serial: 8250: 8250_omap: Do not start RX DMA on THRI interrupt

2023-12-13T17:45:33+00:00

commit c6bb057418876cdfdd29a6f7b8cef54539ee8811 upstream.

Starting RX DMA on THRI interrupt is too early because TX may not have
finished yet.

This change is inspired by commit 90b8596ac460 ("serial: 8250: Prevent
starting up DMA Rx on THRI interrupt") and fixes DMA issues I had with
an AM62 SoC that is using the 8250 OMAP variant.

Cc: stable@vger.kernel.org
Fixes: c26389f998a8 ("serial: 8250: 8250_omap: Add DMA support for UARTs on K3 SoCs")
Signed-off-by: Ronald Wahl 
Reviewed-by: Vignesh Raghavendra 
Link: https://lore.kernel.org/r/20231101171431.16495-1-rwahl@gmx.de
Signed-off-by: Greg Kroah-Hartman

serial: 8250: 8250_omap: Clear UART_HAS_RHR_IT_DIS bit

2023-12-13T17:45:33+00:00

commit 8973ab7a2441b286218f4a5c4c33680e2f139996 upstream.

This fixes commit 439c7183e5b9 ("serial: 8250: 8250_omap: Disable RX
interrupt after DMA enable") which unfortunately set the
UART_HAS_RHR_IT_DIS bit in the UART_OMAP_IER2 register and never
cleared it.

Cc: stable@vger.kernel.org
Fixes: 439c7183e5b9 ("serial: 8250: 8250_omap: Disable RX interrupt after DMA enable")
Signed-off-by: Ronald Wahl 
Reviewed-by: Vignesh Raghavendra 
Link: https://lore.kernel.org/r/20231031110909.11695-1-rwahl@gmx.de
Signed-off-by: Greg Kroah-Hartman

serial: sc16is7xx: address RX timeout interrupt errata

2023-12-13T17:45:32+00:00

commit 08ce9a1b72e38cf44c300a44ac5858533eb3c860 upstream.

This device has a silicon bug that makes it report a timeout interrupt
but no data in the FIFO.

The datasheet states the following in the errata section 18.1.4:

  "If the host reads the receive FIFO at the same time as a
  time-out interrupt condition happens, the host might read 0xCC
  (time-out) in the Interrupt Indication Register (IIR), but bit 0
  of the Line Status Register (LSR) is not set (means there is no
  data in the receive FIFO)."

The errata description seems to indicate it concerns only polled mode of
operation when reading bit 0 of the LSR register. However, tests have
shown and NXP has confirmed that the RXLVL register also yields 0 when
the bug is triggered, and hence the IRQ driven implementation in this
driver is equally affected.

This bug has hit us on production units and when it does, sc16is7xx_irq()
would spin forever because sc16is7xx_port_irq() keeps seeing an
interrupt in the IIR register that is not cleared because the driver
does not call into sc16is7xx_handle_rx() unless the RXLVL register
reports at least one byte in the FIFO.

Fix this by always reading one byte from the FIFO when this condition
is detected in order to clear the interrupt. This approach was
confirmed to be correct by NXP through their support channels.

Tested by: Hugo Villeneuve 

Signed-off-by: Daniel Mack 
Co-Developed-by: Maxim Popov 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231123072818.1394539-1-daniel@zonque.org
Signed-off-by: Greg Kroah-Hartman

ARM: PL011: Fix DMA support

2023-12-13T17:45:32+00:00

commit 58ac1b3799799069d53f5bf95c093f2fe8dd3cc5 upstream.

Since there is no guarantee that the memory returned by
dma_alloc_coherent() is associated with a 'struct page', using the
architecture specific phys_to_page() is wrong, but using
virt_to_page() would be as well.

Stop using sg lists altogether and just use the *_single() functions
instead. This also simplifies the code a bit since the scatterlists in
this driver always have only one entry anyway.

https://lore.kernel.org/lkml/86db0fe5-930d-4cbb-bd7d-03367da38951@app.fastmail.com/
    Use consistent names for dma buffers

gc: Add a commit log from the initial thread:
https://lore.kernel.org/lkml/86db0fe5-930d-4cbb-bd7d-03367da38951@app.fastmail.com/
    Use consistent names for dma buffers

Fixes: cb06ff102e2d7 ("ARM: PL011: Add support for Rx DMA buffer polling.")
Signed-off-by: Arnd Bergmann 
Tested-by: Gregory CLEMENT 
Signed-off-by: Gregory CLEMENT 
Cc: stable 
Link: https://lore.kernel.org/r/20231122171503.235649-1-gregory.clement@bootlin.com
Signed-off-by: Greg Kroah-Hartman

serial: ma35d1: Validate console index before assignment

2023-12-13T17:45:31+00:00

commit f0b9d97a77fa8f18400450713358303a435ab688 upstream.

The console is immediately assigned to the ma35d1 port without
checking its index. This oversight can lead to out-of-bounds
errors when the index falls outside the valid '0' to
MA35_UART_NR range. Such scenario trigges ran error like the
following:

 UBSAN: array-index-out-of-bounds in drivers/tty/serial/ma35d1_serial.c:555:51
 index -1 is out of range for type 'uart_ma35d1_port [17]

Check the index before using it and bail out with a warning.

Fixes: 930cbf92db01 ("tty: serial: Add Nuvoton ma35d1 serial driver support")
Signed-off-by: Andi Shyti 
Cc: Jacky Huang 
Cc:  # v6.5+
Link: https://lore.kernel.org/r/20231204163804.1331415-2-andi.shyti@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: 8250_dw: Add ACPI ID for Granite Rapids-D UART

2023-12-13T17:45:31+00:00

commit e92fad024929c79460403acf946bc9c09ce5c3a9 upstream.

Granite Rapids-D has an additional UART that is enumerated via ACPI.
Add ACPI ID for it.

Signed-off-by: Andy Shevchenko 
Cc: stable 
Link: https://lore.kernel.org/r/20231205195524.2705965-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

hvc/xen: fix event channel handling for secondary consoles

2023-11-28T17:19:57+00:00

commit ef5dd8ec88ac11e8e353164407d55b73c988b369 upstream.

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

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

2023-11-28T17:19:57+00:00

commit 2704c9a5593f4a47620c12dad78838ca62b52f48 upstream.

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 console unplug

2023-11-28T17:19:57+00:00

commit a30badfd7c13fc8763a9e10c5a12ba7f81515a55 upstream.

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 
Signed-off-by: Greg Kroah-Hartman