linux-stable.git/drivers/tty, branch v6.4.7

Revert "8250: add support for ASIX devices with a FIFO bug"

2023-07-23T11:54:08+00:00

commit a82d62f708545d22859584e0e0620da8e3759bbc upstream.

This reverts commit eb26dfe8aa7eeb5a5aa0b7574550125f8aa4c3b3.

Commit eb26dfe8aa7e ("8250: add support for ASIX devices with a FIFO
bug") merged on Jul 13, 2012 adds a quirk for PCI_VENDOR_ID_ASIX
(0x9710). But that ID is the same as PCI_VENDOR_ID_NETMOS defined in
1f8b061050c7 ("[PATCH] Netmos parallel/serial/combo support") merged
on Mar 28, 2005. In pci_serial_quirks array, the NetMos entry always
takes precedence over the ASIX entry even since it was initially
merged, code in that commit is always unreachable.

In my tests, adding the FIFO workaround to pci_netmos_init() makes no
difference, and the vendor driver also does not have such workaround.
Given that the code was never used for over a decade, it's safe to
revert it.

Also, the real PCI_VENDOR_ID_ASIX should be 0x125b, which is used on
their newer AX99100 PCIe serial controllers released on 2016. The FIFO
workaround should not be intended for these newer controllers, and it
was never implemented in vendor driver.

Fixes: eb26dfe8aa7e ("8250: add support for ASIX devices with a FIFO bug")
Cc: stable 
Signed-off-by: Jiaqing Zhao 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20230619155743.827859-1-jiaqing.zhao@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

tty: fix hang on tty device with no_room set

2023-07-23T11:54:06+00:00

commit 4903fde8047a28299d1fc79c1a0dcc255e928f12 upstream.

It is possible to hang pty devices in this case, the reader was
blocking at epoll on master side, the writer was sleeping at
wait_woken inside n_tty_write on slave side, and the write buffer
on tty_port was full, we found that the reader and writer would
never be woken again and blocked forever.

The problem was caused by a race between reader and kworker:
n_tty_read(reader):  n_tty_receive_buf_common(kworker):
copy_from_read_buf()|
                    |room = N_TTY_BUF_SIZE - (ldata->read_head - tail)
                    |room <= 0
n_tty_kick_worker() |
                    |ldata->no_room = true

After writing to slave device, writer wakes up kworker to flush
data on tty_port to reader, and the kworker finds that reader
has no room to store data so room <= 0 is met. At this moment,
reader consumes all the data on reader buffer and calls
n_tty_kick_worker to check ldata->no_room which is false and
reader quits reading. Then kworker sets ldata->no_room=true
and quits too.

If write buffer is not full, writer will wake kworker to flush data
again after following writes, but if write buffer is full and writer
goes to sleep, kworker will never be woken again and tty device is
blocked.

This problem can be solved with a check for read buffer size inside
n_tty_receive_buf_common, if read buffer is empty and ldata->no_room
is true, a call to n_tty_kick_worker is necessary to keep flushing
data to reader.

Cc: 
Fixes: 42458f41d08f ("n_tty: Ensure reader restarts worker for next reader")
Reviewed-by: Ilpo Järvinen 
Signed-off-by: Hui Li 
Message-ID: <1680749090-14106-1-git-send-email-caelli@tencent.com>
Signed-off-by: Greg Kroah-Hartman

tty: serial: imx: fix rs485 rx after tx

2023-07-23T11:54:05+00:00

commit 639949a7031e04c59ec91614eceb9543e9120f43 upstream.

Since commit 79d0224f6bf2 ("tty: serial: imx: Handle RS485 DE signal
active high") RS485 reception no longer works after a transmission.

The following scenario shows the problem:
	1) Open a port in RS485 mode
	2) Receive data from remote (OK)
	3) Transmit data to remote (OK)
	4) Receive data from remote (Nothing received)

In RS485 mode, imx_uart_start_tx() calls imx_uart_stop_rx() and, when the
transmission is complete, imx_uart_stop_tx() calls imx_uart_start_rx().

Since the above commit imx_uart_stop_rx() now sets the loopback bit but
imx_uart_start_rx() does not clear it causing the hardware to remain in
loopback mode and not receive external data.

Fix this by moving the existing loopback disable code to a helper function
and calling it from imx_uart_start_rx() too.

Fixes: 79d0224f6bf2 ("tty: serial: imx: Handle RS485 DE signal active high")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Fuzzey 
Reviewed-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20230616104838.2729694-1-martin.fuzzey@flowbird.group
Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() when iterating clk

2023-07-23T11:54:05+00:00

commit 832e231cff476102e8204a9e7bddfe5c6154a375 upstream.

When the best clk is searched, we iterate over all possible clk.

If we find a better match, the previous one, if any, needs to be freed.
If a better match has already been found, we still need to free the new
one, otherwise it leaks.

Cc:  # v3.3+
Reviewed-by: Krzysztof Kozlowski 
Reviewed-by: Andi Shyti 
Fixes: 5f5a7a5578c5 ("serial: samsung: switch to clkdev based clock lookup")
Signed-off-by: Christophe JAILLET 
Reviewed-by: Jiri Slaby 
Message-ID: 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() in case of error

2023-07-23T11:54:05+00:00

commit a9c09546e903f1068acfa38e1ee18bded7114b37 upstream.

If clk_get_rate() fails, the clk that has just been allocated needs to be
freed.

Cc:  # v3.3+
Reviewed-by: Krzysztof Kozlowski 
Reviewed-by: Andi Shyti 
Fixes: 5f5a7a5578c5 ("serial: samsung: switch to clkdev based clock lookup")
Signed-off-by: Christophe JAILLET 
Reviewed-by: Jiri Slaby 
Message-ID: 
Signed-off-by: Greg Kroah-Hartman

serial: atmel: don't enable IRQs prematurely

2023-07-23T11:54:05+00:00

commit 27a826837ec9a3e94cc44bd9328b8289b0fcecd7 upstream.

The atmel_complete_tx_dma() function disables IRQs at the start
of the function by calling spin_lock_irqsave(&port->lock, flags);
There is no need to disable them a second time using the
spin_lock_irq() function and, in fact, doing so is a bug because
it will enable IRQs prematurely when we call spin_unlock_irq().

Just use spin_lock/unlock() instead without disabling or enabling
IRQs.

Fixes: 08f738be88bb ("serial: at91: add tx dma support")
Signed-off-by: Dan Carpenter 
Reviewed-by: Jiri Slaby 
Acked-by: Richard Genoud 
Link: https://lore.kernel.org/r/cb7c39a9-c004-4673-92e1-be4e34b85368@moroto.mountain
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

tty: serial: fsl_lpuart: add earlycon for imx8ulp platform

2023-07-19T14:37:02+00:00

commit e0edfdc15863ec80a1d9ac6e174dbccc00206dd0 upstream.

Add earlycon support for imx8ulp platform.

Signed-off-by: Sherry Sun 
Cc: stable 
Link: https://lore.kernel.org/r/20230619080613.16522-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250_omap: Use force_suspend and resume for system suspend

2023-07-19T14:36:37+00:00

[ Upstream commit 20a41a62618df85f3a2981008edec5cadd785e0a ]

We should not rely on autosuspend timeout for system suspend. Instead,
let's use force_suspend and force_resume functions. Otherwise the serial
port controller device may not be idled on suspend.

As we are doing a register write on suspend to configure the serial port,
we still need to runtime PM resume the port on suspend.

While at it, let's switch to pm_runtime_resume_and_get() and check for
errors returned. And let's add the missing line break before return to the
suspend function while at it.

Fixes: 09d8b2bdbc5c ("serial: 8250: omap: Provide ability to enable/disable UART as wakeup source")
Signed-off-by: Tony Lindgren 
Tested-by: Dhruva Gole 
Message-ID: <20230614045922.4798-1-tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250: lock port for UART_IER access in omap8250_irq()

2023-07-19T14:36:32+00:00

[ Upstream commit 25614735a647693c1260f253dc3ab32127697806 ]

omap8250_irq() accesses UART_IER. This register is modified twice
by each console write (serial8250_console_write()) under the port
lock. omap8250_irq() must also take the port lock to guanentee
synchronized access to UART_IER.

Since the port lock is already being taken for the stop_rx() callback
and since it is safe to call cancel_delayed_work() while holding the
port lock, simply extend the port lock region to include UART_IER
access.

Fixes: 1fe0e1fa3209 ("serial: 8250_omap: Handle optional overrun-throttle-ms property")
Signed-off-by: John Ogness 
Reviewed-by: Tony Lindgren 
Link: https://lore.kernel.org/r/20230525093159.223817-8-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

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

2023-07-19T14:36:32+00:00

[ Upstream commit 51e45fba14bf08b66bca764a083c7f2e2ff62f01 ]

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 
Signed-off-by: Sasha Levin