linux-stable.git/drivers/tty/serial, branch v5.19.8

tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete

2022-09-08T09:24:01+00:00

commit d5a2e0834364377a5d5a2fff1890a0b3f0bafd1f upstream.

When the user initializes the uart port, and waits for the transmit
engine to complete in lpuart32_set_termios(), if the UART TX fifo has
dirty data and the UARTMODIR enable the flow control, the TX fifo may
never be empty. So here we should disable the flow control first to make
sure the transmit engin can complete.

Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Cc: stable 
Signed-off-by: Sherry Sun 
Link: https://lore.kernel.org/r/20220821101527.10066-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman

tty: serial: atmel: Preserve previous USART mode if RS485 disabled

2022-09-08T09:24:01+00:00

commit 692a8ebcfc24f4a5bea0eb2967e450f584193da6 upstream.

Whenever the atmel_rs485_config() driver method would be called,
the USART mode is reset to normal mode before even checking if
RS485 flag is set, thus resulting in losing the previous USART
mode in the case where the checking fails.

Some tools, such as `linux-serial-test`, lead to the driver calling
this method when doing the setup of the serial port: after setting the
port mode (Hardware Flow Control, Normal Mode, RS485 Mode, etc.),
`linux-serial-test` tries to enable/disable RS485 depending on
the commandline arguments that were passed.

Example of how this issue could reveal itself:
When doing a serial communication with Hardware Flow Control through
`linux-serial-test`, the tool would lead to the driver roughly doing
the following:
- set the corresponding bit to 1 (ATMEL_US_USMODE_HWHS bit in the
ATMEL_US_MR register) through the atmel_set_termios() to enable
Hardware Flow Control
- disable RS485 through the atmel_config_rs485() method
Thus, when the latter is called, the mode will be reset and the
previously set bit is unset, leaving USART in normal mode instead of
the expected Hardware Flow Control mode.

This fix ensures that this reset is only done if the checking for
RS485 succeeds and that the previous mode is preserved otherwise.

Fixes: e8faff7330a35 ("ARM: 6092/1: atmel_serial: support for RS485 communications")
Cc: stable 
Reviewed-by: Ilpo Järvinen 
Signed-off-by: Sergiu Moga 
Link: https://lore.kernel.org/r/20220824142902.502596-1-sergiu.moga@microchip.com
Signed-off-by: Greg Kroah-Hartman

serial: fsl_lpuart: RS485 RTS polariy is inverse

2022-09-08T09:24:00+00:00

commit 846651eca073e2e02e37490a4a52752415d84781 upstream.

The setting of RS485 RTS polarity is inverse in the current driver.

When the property of 'rs485-rts-active-low' is enabled in the dts node,
the RTS signal should be LOW during sending. Otherwise, if there is no
such a property, the RTS should be HIGH during sending.

Fixes: 03895cf41d18 ("tty: serial: fsl_lpuart: Add support for RS-485")
Cc: stable 
Signed-off-by: Nicolas Diaz 
Signed-off-by: Shenwei Wang 
Link: https://lore.kernel.org/r/20220805144529.604856-1-shenwei.wang@nxp.com
Signed-off-by: Greg Kroah-Hartman

tty: serial: Fix refcount leak bug in ucc_uart.c

2022-08-25T09:45:48+00:00

[ Upstream commit d24d7bb2cd947676f9b71fb944d045e09b8b282f ]

In soc_info(), of_find_node_by_type() will return a node pointer
with refcount incremented. We should use of_node_put() when it is
not used anymore.

Acked-by: Timur Tabi 
Signed-off-by: Liang He 
Link: https://lore.kernel.org/r/20220618060850.4058525-1-windhl@126.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: serial: qcom-geni-serial: Fix %lu -> %u in print statements

2022-08-17T13:16:01+00:00

[ Upstream commit 0fec518018cc5ceffa706370b6e3acbbb1e3c798 ]

When we multiply an unsigned int by a u32 we still end up with an
unsigned int. That means we should specify "%u" not "%lu" in the
format code.

NOTE: this fix was chosen instead of somehow promoting the value to
"unsigned long" since the max baud rate from the earlier call to
uart_get_baud_rate() is 4000000 and the max sampling rate is 32.
4000000 * 32 = 0x07a12000, not even close to overflowing 32-bits.

Fixes: c474c775716e ("tty: serial: qcom-geni-serial: Fix get_clk_div_rate() which otherwise could return a sub-optimal clock rate.")
Reported-by: Mark Brown 
Signed-off-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20220802132250.1.Iea061e14157a17e114dbe2eca764568a02d6b889@changeid
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: serial: fsl_lpuart: correct the count of break characters

2022-08-17T13:15:59+00:00

[ Upstream commit 707f816f25590c20e056b3bd4a17ce69b03fe856 ]

The LPUART can't distinguish between a break signal and a framing error,
so need to count the break characters if there is a framing error and
received data is zero instead of the parity error.

Fixes: 5541a9bacfe5 ("serial: fsl_lpuart: handle break and make sysrq work")
Reviewed-by: Michael Walle 
Signed-off-by: Sherry Sun 
Link: https://lore.kernel.org/r/20220725050115.12396-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: serial: qcom-geni-serial: Fix get_clk_div_rate() which otherwise could return a sub-optimal clock rate.

2022-08-17T13:15:59+00:00

[ Upstream commit c474c775716edd46a51bf8161142bbd1545f8733 ]

In the logic around call to clk_round_rate(), for some corner conditions,
get_clk_div_rate() could return an sub-optimal clock rate. Also, if an
exact clock rate was not found lowest clock was being returned.

Search for suitable clock rate in 2 steps
a) exact match or within 2% tolerance
b) within 5% tolerance
This also takes care of corner conditions.

Fixes: c2194bc999d4 ("tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate")
Reviewed-by: Douglas Anderson 
Signed-off-by: Vijaya Krishna Nivarthi 
Link: https://lore.kernel.org/r/1657911343-1909-1-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_bcm2835aux: Add missing clk_disable_unprepare()

2022-08-17T13:15:59+00:00

[ Upstream commit b9f1736e475dba0d6da48fdcb831248ab1597886 ]

The error path when get clock frequency fails in bcm2835aux_serial
driver does not correctly disable the clock.

This flaw was found using a static analysis tool "Hulk Robot", which
reported the following warning when analyzing linux-next/master:

    drivers/tty/serial/8250/8250_bcm2835aux.c:
    warning: clk_disable_unprepare_missing.cocci

The cocci script checks for the existence of clk_disable_unprepare()
paired with clk_prepare_enable().

Add the missing clk_disable_unprepare() to the error path.

Fixes: fcc446c8aa63 ("serial: 8250_bcm2835aux: Add ACPI support")
Reported-by: Hulk Robot 
Reviewed-by: Florian Fainelli 
Signed-off-by: Guo Mengqi 
Link: https://lore.kernel.org/r/20220715023312.37808-1-guomengqi3@huawei.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_bcm7271: Save/restore RTS in suspend/resume

2022-08-17T13:15:53+00:00

[ Upstream commit 3182efd036c1b955403d131258234896cbd9fbeb ]

Commit 9cabe26e65a8 ("serial: 8250_bcm7271: UART errors after resuming
from S2") prevented an early enabling of RTS during resume, but it did
not actively restore the RTS state after resume.

Fixes: 9cabe26e65a8 ("serial: 8250_bcm7271: UART errors after resuming from S2")
Signed-off-by: Doug Berger 
Signed-off-by: Florian Fainelli 
Link: https://lore.kernel.org/r/20220714031316.404918-1-f.fainelli@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_fsl: Don't report FE, PE and OE twice

2022-08-17T13:15:51+00:00

[ Upstream commit 9d3aaceb73acadf134596a2f8db9c451c1332d3d ]

Some Freescale 8250 implementations have the problem that a single long
break results in one irq per character frame time. The code in
fsl8250_handle_irq() that is supposed to handle that uses the BI bit in
lsr_saved_flags to detect such a situation and then skip the second
received character. However it also stores other error bits and so after
a single frame error the character received in the next irq handling is
passed to the upper layer with a frame error, too.

So after a spike on the data line (which is correctly recognized as a
frame error) the following valid character is thrown away, because the
driver reports a frame error for that one, too.

To weaken this problem restrict saving LSR to only the BI bit.

Note however that the handling is still broken:

 - lsr_saved_flags is updated using orig_lsr which is the LSR content
   for the first received char, but there might be more in the FIFO, so
   a character is thrown away that is received later and not necessarily
   the one following the break.
 - The doubled break might be the 2nd and 3rd char in the FIFO, so the
   workaround doesn't catch these, because serial8250_rx_chars() doesn't
   handle the workaround.
 - lsr_saved_flags might have set UART_LSR_BI at the entry of
   fsl8250_handle_irq() which doesn't originate from
   fsl8250_handle_irq()'s "up->lsr_saved_flags |= orig_lsr &
   UART_LSR_BI;" but from e.g. from serial8250_tx_empty().
 - For a long or a short break this isn't about two characters, but more
   or only a single one.

Fixes: 9deaa53ac7fa ("serial: add irq handler for Freescale 16550 errata.")
Acked-by: Ilpo Järvinen 
Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20220704085119.55900-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin