linux-stable.git/drivers/tty/serial, branch v5.17.7

serial: 8250: Correct the clock for EndRun PTP/1588 PCIe device

2022-05-09T07:16:14+00:00

commit 637674fa40059cddcc3ad2212728965072f62ea3 upstream.

The EndRun PTP/1588 dual serial port device is based on the Oxford
Semiconductor OXPCIe952 UART device with the PCI vendor:device ID set
for EndRun Technologies and is therefore driven by a fixed 62.5MHz clock
input derived from the 100MHz PCI Express clock.  The clock rate is
divided by the oversampling rate of 16 as it is supplied to the baud
rate generator, yielding the baud base of 3906250.

Replace the incorrect baud base of 4000000 with the right value of
3906250 then, complementing commit 6cbe45d8ac93 ("serial: 8250: Correct
the clock for OxSemi PCIe devices").

Signed-off-by: Maciej W. Rozycki 
Cc: stable 
Fixes: 1bc8cde46a159 ("8250_pci: Added driver for Endrun Technologies PTP PCIe card.")
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181515270.9383@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman

serial: 8250: Also set sticky MCR bits in console restoration

2022-05-09T07:16:14+00:00

commit 6e6eebdf5e2455f089ccd000754a0deaeb79af82 upstream.

Sticky MCR bits are lost in console restoration if console suspending
has been disabled.  This currently affects the AFE bit, which works in
combination with RTS which we set, so we want to make sure the UART
retains control of its FIFO where previously requested.  Also specific
drivers may need other bits in the future.

Signed-off-by: Maciej W. Rozycki 
Fixes: 4516d50aabed ("serial: 8250: Use canary to restart console after suspend")
Cc: stable@vger.kernel.org # v4.0+
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181518490.9383@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman

serial: amba-pl011: do not time out prematurely when draining tx fifo

2022-05-09T07:16:14+00:00

commit 0e4deb56b0c625efdb70c94f150429e2f2a16fa1 upstream.

The current timeout for draining the tx fifo in RS485 mode is calculated by
multiplying the time it takes to transmit one character (with the given
baud rate) with the maximal number of characters in the tx queue.

This timeout is too short for two reasons:
First when calculating the time to transmit one character integer division
is used which may round down the result in case of a remainder of the
division.

Fix this by rounding up the division result.

Second the hardware may need additional time (e.g for first putting the
characters from the fifo into the shift register) before the characters are
actually put onto the wire.

To be on the safe side double the current maximum number of iterations
that are used to wait for the queue draining.

Fixes: 8d479237727c ("serial: amba-pl011: add RS485 support")
Cc: stable@vger.kernel.org
Signed-off-by: Lino Sanfilippo 
Link: https://lore.kernel.org/r/20220408233503.7251-1-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman

serial: imx: fix overrun interrupts in DMA mode

2022-05-09T07:16:14+00:00

commit 3ee82c6e41f3d2212647ce0bc5a05a0f69097824 upstream.

Commit 76821e222c18 ("serial: imx: ensure that RX irqs are off if RX is
off") accidentally enabled overrun interrupts unconditionally when
deferring DMA enable until after the receiver has been enabled during
startup.

Fix this by using the DMA-initialised instead of DMA-enabled flag to
determine whether overrun interrupts should be enabled.

Note that overrun interrupts are already accounted for in
imx_uart_clear_rx_errors() when using DMA since commit 41d98b5da92f
("serial: imx-serial - update RX error counters when DMA is used").

Fixes: 76821e222c18 ("serial: imx: ensure that RX irqs are off if RX is off")
Cc: stable@vger.kernel.org      # 4.17
Cc: Uwe Kleine-König 
Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20220411081957.7846-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: samsung_tty: do not unlock port->lock for uart_write_wakeup()

2022-04-13T17:27:26+00:00

[ Upstream commit 988c7c00691008ea1daaa1235680a0da49dab4e8 ]

The commit c15c3747ee32 (serial: samsung: fix potential soft lockup
during uart write) added an unlock of port->lock before
uart_write_wakeup() and a lock after it. It was always problematic to
write data from tty_ldisc_ops::write_wakeup and it was even documented
that way. We fixed the line disciplines to conform to this recently.
So if there is still a missed one, we should fix them instead of this
workaround.

On the top of that, s3c24xx_serial_tx_dma_complete() in this driver
still holds the port->lock while calling uart_write_wakeup().

So revert the wrap added by the commit above.

Cc: Thomas Abraham 
Cc: Kyungmin Park 
Cc: Hyeonkook Kim 
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20220308115153.4225-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250: fix XOFF/XON sending when DMA is used

2022-04-08T11:58:30+00:00

[ Upstream commit f58c252e30cf74f68b0054293adc03b5923b9f0e ]

When 8250 UART is using DMA, x_char (XON/XOFF) is never sent
to the wire. After this change, x_char is injected correctly.

Create uart_xchar_out() helper for sending the x_char out and
accounting related to it. It seems that almost every driver
does these same steps with x_char. Except for 8250, however,
almost all currently lack .serial_out so they cannot immediately
take advantage of this new helper.

The downside of this patch is that it might reintroduce
the problems some devices faced with mixed DMA/non-DMA transfer
which caused revert f967fc8f165f (Revert "serial: 8250_dma:
don't bother DMA with small transfers"). However, the impact
should be limited to cases with XON/XOFF (that didn't work
with DMA capable devices to begin with so this problem is not
very likely to cause a major issue, if any at all).

Fixes: 9ee4b83e51f74 ("serial: 8250: Add support for dmaengine")
Reported-by: Gilles Buloz 
Tested-by: Gilles Buloz 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20220314091432.4288-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

kgdboc: fix return value of __setup handler

2022-04-08T11:58:30+00:00

[ Upstream commit ab818c7aa7544bf8d2dd4bdf68878b17a02eb332 ]

__setup() handlers should return 1 to obsolete_checksetup() in
init/main.c to indicate that the boot option has been handled.
A return of 0 causes the boot option/value to be listed as an Unknown
kernel parameter and added to init's (limited) environment strings.
So return 1 from kgdboc_option_setup().

Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc7
  kgdboc=kbd kgdbts=", will be passed to user space.

 Run /sbin/init as init process
   with arguments:
     /sbin/init
   with environment:
     HOME=/
     TERM=linux
     BOOT_IMAGE=/boot/bzImage-517rc7
     kgdboc=kbd
     kgdbts=

Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Fixes: 1bd54d851f50 ("kgdboc: Passing ekgdboc to command line causes panic")
Fixes: f2d937f3bf00 ("consoles: polling support, kgdboc")
Cc: He Zhe 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: kgdb-bugreport@lists.sourceforge.net
Cc: Jason Wessel 
Cc: Daniel Thompson 
Cc: Douglas Anderson 
Cc: linux-serial@vger.kernel.org
Reported-by: Igor Zhbanov 
Reviewed-by: Douglas Anderson 
Signed-off-by: Randy Dunlap 
Link: https://lore.kernel.org/r/20220309033018.17936-1-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250: Fix race condition in RTS-after-send handling

2022-04-08T11:58:26+00:00

[ Upstream commit dedab69fd650ea74710b2e626e63fd35584ef773 ]

Set em485->active_timer = NULL isn't always enough to take out the stop
timer. While there is a check that it acts in the right state (i.e.
waiting for RTS-after-send to pass after sending some chars) but the
following might happen:

 - CPU1: some chars send, shifter becomes empty, stop tx timer armed
 - CPU0: more chars send before RTS-after-send expired
 - CPU0: shifter empty irq, port lock taken
 - CPU1: tx timer triggers, waits for port lock
 - CPU0: em485->active_timer = &em485->stop_tx_timer, hrtimer_start(),
   releases lock()
 - CPU1: get lock, see em485->active_timer == &em485->stop_tx_timer,
   tear down RTS too early

This fix bases on research done by Steffen Trumtrar.

Fixes: b86f86e8e7c5 ("serial: 8250: fix potential deadlock in rs485-mode")
Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20220215160236.344236-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_lpss: Balance reference count for PCI DMA device

2022-04-08T11:58:25+00:00

[ Upstream commit 5318f70da7e82649d794fc27d8a127c22aa3566e ]

The pci_get_slot() increases its reference count, the caller
must decrement the reference count by calling pci_dev_put().

Fixes: 9a1870ce812e ("serial: 8250: don't use slave_id of dma_slave_config")
Depends-on: a13e19cf3dc1 ("serial: 8250_lpss: split LPSS driver to separate module")
Reported-by: Qing Wang 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20220223151240.70248-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_mid: Balance reference count for PCI DMA device

2022-04-08T11:58:25+00:00

[ Upstream commit 67ec6dd0b257bd81b4e9fcac89b29da72f6265e5 ]

The pci_get_slot() increases its reference count, the caller
must decrement the reference count by calling pci_dev_put().

Fixes: 90b9aacf912a ("serial: 8250_pci: add Intel Tangier support")
Fixes: f549e94effa1 ("serial: 8250_pci: add Intel Penwell ports")
Reported-by: Qing Wang 
Signed-off-by: Andy Shevchenko 
Depends-on: d9eda9bab237 ("serial: 8250_pci: Intel MID UART support to its own driver")
Link: https://lore.kernel.org/r/20220215100920.41984-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin