commit 81100b9a7b upstream.
On (H)SCIF with a Baud Rate Generator for External Clock (BRG), there
are multiple ways to configure the requested serial speed. If firmware
uses a different method than Linux, and if any debug info is printed
after the Bit Rate Register (SCBRR) is restored, but before termios is
reconfigured (which configures the alternative method), the system may
lock-up during resume.
Fix this by saving and restoring the contents of the BRG Frequency
Division (SCDL) and Clock Select (SCCKS) registers as well.
Also save and restore the HSCIF's Sampling Rate Register (HSSRR), which
configures the sampling point, and the SCIFA/SCIFB's Serial Port Control
and Data Registers (SCPCR/SCPDR), which configure the optional control
flow signals.
After this, all registers that are not saved/restored are either:
- read-only,
- write-only,
- status registers containing flags with clear-after-set semantics,
- FIFO Data Count Trigger registers, which do not matter much for
the serial console.
Fixes: 22a6984c5b ("serial: sh-sci: Update the suspend/resume support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/11c2eab45d48211e75d8b8202cce60400880fe55.1741114989.git.geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 22a6984c5b ]
The Renesas RZ/G3S supports a power saving mode where power to most of the
SoC components is turned off. When returning from this power saving mode,
SoC components need to be re-configured.
The SCIFs on the Renesas RZ/G3S need to be re-configured as well when
returning from this power saving mode. The sh-sci code already configures
the SCIF clocks, power domain and registers by calling uart_resume_port()
in sci_resume(). On suspend path the SCIF UART ports are suspended
accordingly (by calling uart_suspend_port() in sci_suspend()). The only
missing setting is the reset signal. For this assert/de-assert the reset
signal on driver suspend/resume.
In case the no_console_suspend is specified by the user, the registers need
to be saved on suspend path and restore on resume path. To do this the
sci_console_save()/sci_console_restore() functions were added. There is no
need to cache/restore the status or FIFO registers. Only the control
registers. The registers that will be saved/restored on suspend/resume are
specified by the struct sci_suspend_regs data structure.
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20250207113313.545432-1-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1bd2aad57d ]
The following splat has been observed on a SAMA5D27 platform using
atmel_serial:
BUG: sleeping function called from invalid context at kernel/irq/manage.c:738
in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 27, name: kworker/u5:0
preempt_count: 1, expected: 0
INFO: lockdep is turned off.
irq event stamp: 0
hardirqs last enabled at (0): [<00000000>] 0x0
hardirqs last disabled at (0): [<c01588f0>] copy_process+0x1c4c/0x7bec
softirqs last enabled at (0): [<c0158944>] copy_process+0x1ca0/0x7bec
softirqs last disabled at (0): [<00000000>] 0x0
CPU: 0 UID: 0 PID: 27 Comm: kworker/u5:0 Not tainted 6.13.0-rc7+ #74
Hardware name: Atmel SAMA5
Workqueue: hci0 hci_power_on [bluetooth]
Call trace:
unwind_backtrace from show_stack+0x18/0x1c
show_stack from dump_stack_lvl+0x44/0x70
dump_stack_lvl from __might_resched+0x38c/0x598
__might_resched from disable_irq+0x1c/0x48
disable_irq from mctrl_gpio_disable_ms+0x74/0xc0
mctrl_gpio_disable_ms from atmel_disable_ms.part.0+0x80/0x1f4
atmel_disable_ms.part.0 from atmel_set_termios+0x764/0x11e8
atmel_set_termios from uart_change_line_settings+0x15c/0x994
uart_change_line_settings from uart_set_termios+0x2b0/0x668
uart_set_termios from tty_set_termios+0x600/0x8ec
tty_set_termios from ttyport_set_flow_control+0x188/0x1e0
ttyport_set_flow_control from wilc_setup+0xd0/0x524 [hci_wilc]
wilc_setup [hci_wilc] from hci_dev_open_sync+0x330/0x203c [bluetooth]
hci_dev_open_sync [bluetooth] from hci_dev_do_open+0x40/0xb0 [bluetooth]
hci_dev_do_open [bluetooth] from hci_power_on+0x12c/0x664 [bluetooth]
hci_power_on [bluetooth] from process_one_work+0x998/0x1a38
process_one_work from worker_thread+0x6e0/0xfb4
worker_thread from kthread+0x3d4/0x484
kthread from ret_from_fork+0x14/0x28
This warning is emitted when trying to toggle, at the highest level,
some flow control (with serdev_device_set_flow_control) in a device
driver. At the lowest level, the atmel_serial driver is using
serial_mctrl_gpio lib to enable/disable the corresponding IRQs
accordingly. The warning emitted by CONFIG_DEBUG_ATOMIC_SLEEP is due to
disable_irq (called in mctrl_gpio_disable_ms) being possibly called in
some atomic context (some tty drivers perform modem lines configuration
in regions protected by port lock).
Split mctrl_gpio_disable_ms into two differents APIs, a non-blocking one
and a blocking one. Replace mctrl_gpio_disable_ms calls with the
relevant version depending on whether the call is protected by some port
lock.
Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Acked-by: Richard Genoud <richard.genoud@bootlin.com>
Link: https://lore.kernel.org/r/20250217-atomic_sleep_mctrl_serial_gpio-v3-1-59324b313eef@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit e1ca3ff28a upstream.
startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS.
The register is also accessed from write() callback.
If console were printing and startup()/shutdown() callback
gets called, its access to the register could be overwritten.
Add port->lock to startup()/shutdown() callbacks to make sure
their access to SIFIVE_SERIAL_IE_OFFS is synchronized against
write() callback.
Fixes: 45c054d081 ("tty: serial: add driver for the SiFive UART")
Signed-off-by: Ryo Takakura <ryotkkr98@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Rule: add
Link: https://lore.kernel.org/stable/20250330003522.386632-1-ryotkkr98%40gmail.com
Link: https://lore.kernel.org/r/20250412001847.183221-1-ryotkkr98@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7094832b5a upstream.
The MSM UART DM controller supports different working modes, e.g. DMA or
the "single-character mode", where all reads/writes operate on a single
character rather than 4 chars (32-bit) at once. When using earlycon,
__msm_console_write() always writes 4 characters at a time, but we don't
know which mode the bootloader was using and we don't set the mode either.
This causes garbled output if the bootloader was using the single-character
mode, because only every 4th character appears in the serial console, e.g.
"[ 00oni pi 000xf0[ 00i s 5rm9(l)l s 1 1 SPMTA 7:C 5[ 00A ade k d[
00ano:ameoi .Q1B[ 00ac _idaM00080oo'"
If the bootloader was using the DMA ("DM") mode, output would likely fail
entirely. Later, when the full serial driver probes, the port is
re-initialized and output works as expected.
Fix this also for earlycon by clearing the DMEN register and
reset+re-enable the transmitter to apply the change. This ensures the
transmitter is in the expected state before writing any output.
Cc: stable <stable@kernel.org>
Fixes: 0efe729634 ("tty: serial: msm: Add earlycon support")
Signed-off-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250408-msm-serial-earlycon-v1-1-429080127530@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ee6a44da3c upstream.
This requirement was overeagerly loosened in commit 2f83e38a09
("tty: Permit some TIOCL_SETSEL modes without CAP_SYS_ADMIN"), but as
it turns out,
(1) the logic I implemented there was inconsistent (apologies!),
(2) TIOCL_SELMOUSEREPORT might actually be a small security risk
after all, and
(3) TIOCL_SELMOUSEREPORT is only meant to be used by the mouse
daemon (GPM or Consolation), which runs as CAP_SYS_ADMIN
already.
In more detail:
1. The previous patch has inconsistent logic:
In commit 2f83e38a09 ("tty: Permit some TIOCL_SETSEL modes
without CAP_SYS_ADMIN"), we checked for sel_mode ==
TIOCL_SELMOUSEREPORT, but overlooked that the lower four bits of
this "mode" parameter were actually used as an additional way to
pass an argument. So the patch did actually still require
CAP_SYS_ADMIN, if any of the mouse button bits are set, but did not
require it if none of the mouse buttons bits are set.
This logic is inconsistent and was not intentional. We should have
the same policies for using TIOCL_SELMOUSEREPORT independent of the
value of the "hidden" mouse button argument.
I sent a separate documentation patch to the man page list with
more details on TIOCL_SELMOUSEREPORT:
https://lore.kernel.org/all/20250223091342.35523-2-gnoack3000@gmail.com/
2. TIOCL_SELMOUSEREPORT is indeed a potential security risk which can
let an attacker simulate "keyboard" input to command line
applications on the same terminal, like TIOCSTI and some other
TIOCLINUX "selection mode" IOCTLs.
By enabling mouse reporting on a terminal and then injecting mouse
reports through TIOCL_SELMOUSEREPORT, an attacker can simulate
mouse movements on the same terminal, similar to the TIOCSTI
keystroke injection attacks that were previously possible with
TIOCSTI and other TIOCL_SETSEL selection modes.
Many programs (including libreadline/bash) are then prone to
misinterpret these mouse reports as normal keyboard input because
they do not expect input in the X11 mouse protocol form. The
attacker does not have complete control over the escape sequence,
but they can at least control the values of two consecutive bytes
in the binary mouse reporting escape sequence.
I went into more detail on that in the discussion at
https://lore.kernel.org/all/20250221.0a947528d8f3@gnoack.org/
It is not equally trivial to simulate arbitrary keystrokes as it
was with TIOCSTI (commit 83efeeeb3d ("tty: Allow TIOCSTI to be
disabled")), but the general mechanism is there, and together with
the small number of existing legit use cases (see below), it would
be better to revert back to requiring CAP_SYS_ADMIN for
TIOCL_SELMOUSEREPORT, as it was already the case before
commit 2f83e38a09 ("tty: Permit some TIOCL_SETSEL modes without
CAP_SYS_ADMIN").
3. TIOCL_SELMOUSEREPORT is only used by the mouse daemons (GPM or
Consolation), and they are the only legit use case:
To quote console_codes(4):
The mouse tracking facility is intended to return
xterm(1)-compatible mouse status reports. Because the console
driver has no way to know the device or type of the mouse, these
reports are returned in the console input stream only when the
virtual terminal driver receives a mouse update ioctl. These
ioctls must be generated by a mouse-aware user-mode application
such as the gpm(8) daemon.
Jared Finder has also confirmed in
https://lore.kernel.org/all/491f3df9de6593df8e70dbe77614b026@finder.org/
that Emacs does not call TIOCL_SELMOUSEREPORT directly, and it
would be difficult to find good reasons for doing that, given that
it would interfere with the reports that GPM is sending.
More information on the interaction between GPM, terminals and the
kernel with additional pointers is also available in this patch:
https://lore.kernel.org/all/a773e48920aa104a65073671effbdee665c105fc.1603963593.git.tammo.block@gmail.com/
For background on who else uses TIOCL_SELMOUSEREPORT: Debian Code
search finds one page of results, the only two known callers are
the two mouse daemons GPM and Consolation. (GPM does not show up
in the search results because it uses literal numbers to refer to
TIOCLINUX-related enums. I looked through GPM by hand instead.
TIOCL_SELMOUSEREPORT is also not used from libgpm.)
https://codesearch.debian.net/search?q=TIOCL_SELMOUSEREPORT
Cc: Jared Finder <jared@finder.org>
Cc: Jann Horn <jannh@google.com>
Cc: Hanno Böck <hanno@hboeck.de>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: stable <stable@kernel.org>
Fixes: 2f83e38a09 ("tty: Permit some TIOCL_SETSEL modes without CAP_SYS_ADMIN")
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20250411070144.3959-2-gnoack3000@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e98ab45ec5 ]
No need to overwrite the whole UARTMODIR register before waiting the
transmit engine complete, actually our target here is only to disable
CTS flow control to avoid the dirty data in TX FIFO may block the
transmit engine complete.
Also delete the following duplicate CTS disable configuration.
Fixes: d5a2e08343 ("tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20250307065446.1122482-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 3cc16ae096 upstream.
Most lpuart functions have the parameter struct uart_port *port, but
still use the &sport->port to get the uart_port instead of use it
directly, let's simply the code logic, directly use this struct instead
of covert it from struct sport.
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20250312023904.1343351-3-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit b6a8f6ab2c ]
Use u32 and u8 rather than unsigned long or unsigned char for register
variables for clarity and consistency.
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20250312023904.1343351-2-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: e98ab45ec5 ("tty: serial: lpuart: only disable CTS instead of overwriting the whole UARTMODIR register")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d97aa06667 ]
tty_write_room() returns an "unsigned int". So in case some insane
driver (like my tty test driver) returns (legitimate) UINT_MAX from its
tty_operations::write_room(), n_tty is confused on several places.
For example, in process_output_block(), the result of tty_write_room()
is stored into (signed) "int". So this UINT_MAX suddenly becomes -1. And
that is extended to ssize_t and returned from process_output_block().
This causes a write() to such a node to receive -EPERM (which is -1).
Fix that by using proper "unsigned int" and proper "== 0" test. And
return 0 constant directly in that "if", so that it is immediately clear
what is returned ("space" equals to 0 at that point).
Similarly for process_output() and __process_echoes().
Note this does not fix any in-tree driver as of now.
If you want "Fixes: something", it would be commit 03b3b1a240 ("tty:
make tty_operations::write_room return uint"). I intentionally do not
mark this patch by a real tag below.
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250317070046.24386-6-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit a26503092c upstream.
When flushing transmit side DMA, it is the transmit channel that should
be terminated, not the receive channel.
Fixes: 9e512eaaf8 ("serial: 8250: Fix fifo underflow on flush")
Cc: stable <stable@kernel.org>
Reported-by: Wentao Guan <guanwentao@uniontech.com>
Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250224121831.1429323-1-jkeeping@inmusicbrands.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2790ce2395 upstream.
If stm32_usart_start_tx is called with an empty xmit buffer, RTS GPIO
could be deasserted prematurely, as bytes in TX FIFO are still
transmitting.
So this patch remove rts disable when xmit buffer is empty.
Fixes: d7c7671616 ("serial: stm32: Use TC interrupt to deassert GPIO RTS in RS485 mode")
Cc: stable <stable@kernel.org>
Signed-off-by: Cheick Traore <cheick.traore@foss.st.com>
Link: https://lore.kernel.org/r/20250320152540.709091-1-cheick.traore@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f5cb528d64 upstream.
According to the LPUART reference manual, TXRTSE and TXRTSPOL of MODIR
register only can be changed when the transmitter is disabled.
So disable the transmitter before changing RS485 related registers and
re-enable it after the change is done.
Fixes: 67b0183786 ("tty: serial: lpuart: Add RS485 support for 32-bit uart flavour")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250312022503.1342990-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9e512eaaf8 upstream.
When flushing the serial port's buffer, uart_flush_buffer() calls
kfifo_reset() but if there is an outstanding DMA transfer then the
completion function will consume data from the kfifo via
uart_xmit_advance(), underflowing and leading to ongoing DMA as the
driver tries to transmit another 2^32 bytes.
This is readily reproduced with serial-generic and amidi sending even
short messages as closing the device on exit will wait for the fifo to
drain and in the underflow case amidi hangs for 30 seconds on exit in
tty_wait_until_sent(). A trace of that gives:
kworker/1:1-84 [001] 51.769423: bprint: serial8250_tx_dma: tx_size=3 fifo_len=3
amidi-763 [001] 51.769460: bprint: uart_flush_buffer: resetting fifo
irq/21-fe530000-76 [000] 51.769474: bprint: __dma_tx_complete: tx_size=3
irq/21-fe530000-76 [000] 51.769479: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294967293
irq/21-fe530000-76 [000] 51.781295: bprint: __dma_tx_complete: tx_size=4096
irq/21-fe530000-76 [000] 51.781301: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294963197
irq/21-fe530000-76 [000] 51.793131: bprint: __dma_tx_complete: tx_size=4096
irq/21-fe530000-76 [000] 51.793135: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294959101
irq/21-fe530000-76 [000] 51.804949: bprint: __dma_tx_complete: tx_size=4096
Since the port lock is held in when the kfifo is reset in
uart_flush_buffer() and in __dma_tx_complete(), adding a flush_buffer
hook to adjust the outstanding DMA byte count is sufficient to avoid the
kfifo underflow.
Fixes: 9ee4b83e51 ("serial: 8250: Add support for dmaengine")
Cc: stable <stable@kernel.org>
Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>
Link: https://lore.kernel.org/r/20250208124148.1189191-1-jkeeping@inmusicbrands.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e8486bd50e upstream.
The documentation of the __uart_read_properties() states that
->iotype member is always altered after the function call, but
the code doesn't do that in the case when use_defaults == false
and the value of reg-io-width is unsupported. Make sure the code
follows the documentation.
Note, the current users of the uart_read_and_validate_port_properties()
will fail and the change doesn't affect their behaviour, neither
users of uart_read_port_properties() will be affected since the
alteration happens there even in the current code flow.
Fixes: e894b6005d ("serial: port: Introduce a common helper to read properties")
Cc: stable <stable@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250124161530.398361-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 166ac2bba1 upstream.
Currently the ->iotype is always assigned to the UPIO_MEM when
the respective property is not found. However, this will not
support the cases when user wants to have UPIO_PORT to be set
or preserved. Support this scenario by checking ->iobase value
and default the ->iotype respectively.
Fixes: 1117a6fdc7 ("serial: 8250_of: Switch to use uart_read_port_properties()")
Fixes: e894b6005d ("serial: port: Introduce a common helper to read properties")
Cc: stable <stable@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250124161530.398361-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e95cb63e57 ]
In the B0 revision, the RTS pin remains high due to incorrect hardware
mapping. To address this issue, enable auto-direction control with the
RTS bit in ADCL_CFG_REG. This configuration ensures that the RTS pin
goes low when the terminal is opened and high when the terminal is
closed. Additionally, we reset the step counter for Rx and Tx engines
by writing into FRAC_DIV_CFG_REG.
Signed-off-by: Rengarajan S <rengarajan.s@microchip.com>
Link: https://lore.kernel.org/r/20241218094017.18290-1-rengarajan.s@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 535a07698b ]
parport_serial driver uses subset of WCH IDs that are present in 8250_pci.
Share them via pci_ids.h and switch parport_serial to use defined constants.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20241204031114.1029882-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 16076ca3a1 ]
There are two sites of the same brand: wch.cn and wch-ic.com.
They are property of the same company, but it appears that they
managed to get two different PCI vendor IDs. Rename them accordingly
using standard pattern, i.e. PCI_VENDOR_ID_...
While at it, move to PCI_VDEVICE() in the ID tables.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20241204031114.1029882-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 9f7dea875c upstream.
In the sh-sci driver, sci_ports[0] is used by earlycon. If the earlycon is
still active when sci_probe() is called and the new serial port is supposed
to map to sci_ports[0], return -EBUSY to prevent breaking the earlycon.
This situation should occurs in debug scenarios, and users should be
aware of the potential conflict.
Fixes: 0b0cced19a ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-4-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit eaeee4225d upstream.
The port_cfg object is used by serial_console_write(), which serves as
the write function for the earlycon device. Marking port_cfg as __initdata
causes it to be freed after kernel initialization, resulting in earlycon
becoming unavailable thereafter. Remove the __initdata macro from port_cfg
to resolve this issue.
Fixes: 0b0cced19a ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable@vger.kernel.org
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Fixes: 0b0cced19a ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Link: https://lore.kernel.org/r/20250116182249.3828577-2-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2f83e38a09 upstream.
With this, processes without CAP_SYS_ADMIN are able to use TIOCLINUX with
subcode TIOCL_SETSEL, in the selection modes TIOCL_SETPOINTER,
TIOCL_SELCLEAR and TIOCL_SELMOUSEREPORT.
TIOCL_SETSEL was previously changed to require CAP_SYS_ADMIN, as this IOCTL
let callers change the selection buffer and could be used to simulate
keypresses. These three TIOCL_SETSEL selection modes, however, are safe to
use, as they do not modify the selection buffer.
This fixes a mouse support regression that affected Emacs (invisible mouse
cursor).
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/ee3ec63269b43b34e1c90dd8c9743bf8@finder.org
Fixes: 8d1b43f6a6 ("tty: Restrict access to TIOCLINUX' copy-and-paste subcommands")
Signed-off-by: Günther Noack <gnoack@google.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20250110142122.1013222-1-gnoack@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b06f388994 upstream.
lockdep detects the following circular locking dependency:
CPU 0 CPU 1
========================== ============================
cdns_uart_isr() printk()
uart_port_lock(port) console_lock()
cdns_uart_console_write()
if (!port->sysrq)
uart_port_lock(port)
uart_handle_break()
port->sysrq = ...
uart_handle_sysrq_char()
printk()
console_lock()
The fixed commit attempts to avoid this situation by only taking the
port lock in cdns_uart_console_write if port->sysrq unset. However, if
(as shown above) cdns_uart_console_write runs before port->sysrq is set,
then it will try to take the port lock anyway. This may result in a
deadlock.
Fix this by splitting sysrq handling into two parts. We use the prepare
helper under the port lock and defer handling until we release the lock.
Fixes: 74ea66d4ca ("tty: xuartps: Improve sysrq handling")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Cc: stable@vger.kernel.org # c980248179: serial: xilinx_uartps: Use port lock wrappers
Acked-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20250110213822.2107462-1-sean.anderson@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit d91f98be26 ]
After a console has written a record into UART_TX, it uses
wait_for_xmitr() to wait until the data has been sent out before
returning. However, wait_for_xmitr() will timeout after 10ms,
regardless if the data has been transmitted or not.
For single bytes, this timeout is sufficient even at very slow
baud rates, such as 1200bps. However, when FIFO mode is used,
there may be 64 bytes pushed into the FIFO at once. At a baud
rate of 115200bps, the 10ms timeout is still sufficient. But
when using lower baud rates (such as 57600bps), the timeout
is _not_ sufficient. This causes longer lines to be cut off,
resulting in lost and horribly misformatted output on the
console.
When using FIFO mode, take the number of bytes into account to
determine an appropriate maximum timeout. Increasing the timeout
does not affect performance since ideally the timeout never
occurs.
Fixes: 8f3631f0f6 ("serial/8250: Use fifo in 8250 console driver")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Wander Lairson Costa <wander@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250107212702.169493-2-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6dd1de91e7 ]
The LKP robot complains about:
drivers/tty/mips_ejtag_fdc.c:1224:31: error: incompatible pointer types passing 'const char *[1]' to parameter of type 'const u8 **' (aka 'const unsigned char **')
Fix this by turning the missing pieces (fetch from kgdbfdc_wbuf) to u8
too. Note the filling part (kgdbfdc_write_char()) already receives and
stores u8 to kgdbfdc_wbuf.
Fixes: ce7cbd9a6c ("tty: mips_ejtag_fdc: use u8 for character pointers")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202501101327.oGdWbmuk-lkp@intel.com/
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250110115228.603980-1-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ceb8bf2cea ]
Commit cdd30ebb1b ("module: Convert symbol namespace to string
literal") only converted MODULE_IMPORT_NS() and EXPORT_SYMBOL_NS(),
leaving DEFAULT_SYMBOL_NAMESPACE as a macro expansion.
This commit converts DEFAULT_SYMBOL_NAMESPACE in the same way to avoid
annoyance for the default namespace as well.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Stable-dep-of: 2505f87eb3 ("hwmon: (nct6775): Actually make use of the HWMON_NCT6775 symbol namespace")
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 0cfc36ea51 upstream.
Commit 30e945861f ("serial: stm32: add support for break control")
added another usage of the port lock, but was merged on the same day as
c5d0666255 ("serial: stm32: Use port lock wrappers"), therefore the
latter did not update this usage to use the port lock wrappers.
Fixes: c5d0666255 ("serial: stm32: Use port lock wrappers")
Cc: stable <stable@kernel.org>
Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20241216145323.111612-1-ben.wolsieffer@hefring.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ed2761958a upstream.
The commit f9b11229b7 ("serial: 8250: Fix PM usage_count for console
handover") fixed one runtime PM usage counter balance problem that
occurs because .dev is not set during univ8250 setup preventing call to
pm_runtime_get_sync(). Later, univ8250_console_exit() will trigger the
runtime PM usage counter underflow as .dev is already set at that time.
Call pm_runtime_get_sync() to balance the RPM usage counter also in
serial8250_register_8250_port() before trying to add the port.
Reported-by: Borislav Petkov (AMD) <bp@alien8.de>
Fixes: bedb404e91 ("serial: 8250_port: Don't use power management for kernel console")
Cc: stable <stable@kernel.org>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20241210170120.2231-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7cc0e0a43a upstream.
On the Renesas RZ/G3S, when doing suspend to RAM, the uart_suspend_port()
is called. The uart_suspend_port() calls 3 times the
struct uart_port::ops::tx_empty() before shutting down the port.
According to the documentation, the struct uart_port::ops::tx_empty()
API tests whether the transmitter FIFO and shifter for the port is
empty.
The Renesas RZ/G3S SCIFA IP reports the number of data units stored in the
transmit FIFO through the FDR (FIFO Data Count Register). The data units
in the FIFOs are written in the shift register and transmitted from there.
The TEND bit in the Serial Status Register reports if the data was
transmitted from the shift register.
In the previous code, in the tx_empty() API implemented by the sh-sci
driver, it is considered that the TX is empty if the hardware reports the
TEND bit set and the number of data units in the FIFO is zero.
According to the HW manual, the TEND bit has the following meaning:
0: Transmission is in the waiting state or in progress.
1: Transmission is completed.
It has been noticed that when opening the serial device w/o using it and
then switch to a power saving mode, the tx_empty() call in the
uart_port_suspend() function fails, leading to the "Unable to drain
transmitter" message being printed on the console. This is because the
TEND=0 if nothing has been transmitted and the FIFOs are empty. As the
TEND=0 has double meaning (waiting state, in progress) we can't
determined the scenario described above.
Add a software workaround for this. This sets a variable if any data has
been sent on the serial console (when using PIO) or if the DMA callback has
been called (meaning something has been transmitted). In the tx_empty()
API the status of the DMA transaction is also checked and if it is
completed or in progress the code falls back in checking the hardware
registers instead of relying on the software variable.
Fixes: 73a19e4c03 ("serial: sh-sci: Add DMA support.")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20241125115856.513642-1-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit cad4dda82c ]
SG2044 relys on an internal divisor when calculating bitrate, which
means a wrong clock for the most common bitrates. So add a quirk for
this uart device to skip the set rate call and only relys on the
internal UART divisor.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Link: https://lore.kernel.org/r/20241024062105.782330-4-inochiama@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit b5a23a60e8 upstream.
When CONFIG_DMA_ENGINE is disabled, the driver now fails to build:
drivers/tty/serial/amba-pl011.c: In function 'pl011_unthrottle_rx':
drivers/tty/serial/amba-pl011.c:1822:16: error: 'struct uart_amba_port' has no member named 'using_rx_dma'
1822 | if (uap->using_rx_dma) {
| ^~
drivers/tty/serial/amba-pl011.c:1823:20: error: 'struct uart_amba_port' has no member named 'dmacr'
1823 | uap->dmacr |= UART011_RXDMAE;
| ^~
drivers/tty/serial/amba-pl011.c:1824:32: error: 'struct uart_amba_port' has no member named 'dmacr'
1824 | pl011_write(uap->dmacr, uap, REG_DMACR);
| ^~
Add the missing #ifdef check around these field accesses, matching
what other parts of this driver do.
Fixes: 2bcacc1c87 ("serial: amba-pl011: Fix RX stall when DMA is used")
Cc: stable <stable@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202411140617.nkjeHhsK-lkp@intel.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20241115110021.744332-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2bcacc1c87 upstream.
Function pl011_throttle_rx() calls pl011_stop_rx() to disable RX, which
also disables the RX DMA by clearing the RXDMAE bit of the DMACR
register. However, to properly unthrottle RX when DMA is used, the
function pl011_unthrottle_rx() is expected to set the RXDMAE bit of
the DMACR register, which it currently lacks. This causes RX to stall
after the throttle API is called.
Set RXDMAE bit in the DMACR register while unthrottling RX if RX DMA is
used.
Fixes: 211565b100 ("serial: pl011: UPSTAT_AUTORTS requires .throttle/unthrottle")
Cc: stable@vger.kernel.org
Signed-off-by: Kartik Rajput <kkartik@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20241113092629.60226-1-kkartik@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bcc7ba6688 upstream.
Currently in omap_8250_shutdown, the dma->rx_running flag is
set to zero in omap_8250_rx_dma_flush. Next pm_runtime_get_sync
is called, which is a runtime resume call stack which can
re-set the flag. When the call omap_8250_shutdown returns, the
flag is expected to be UN-SET, but this is not the case. This
is causing issues the next time UART is re-opened and
omap_8250_rx_dma is called. Fix by moving pm_runtime_get_sync
before the omap_8250_rx_dma_flush.
cc: stable@vger.kernel.org
Fixes: 0e31c8d173 ("tty: serial: 8250_omap: add custom DMA-RX callback")
Signed-off-by: Bin Liu <b-liu@ti.com>
[Judith: Add commit message]
Signed-off-by: Judith Mendez <jm@ti.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20241031172315.453750-1-jm@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 166105c903 upstream.
The F81216E is a LPC/eSPI to 4 UART Super I/O and is mostly compatible with
the F81216H, but does not support RS-485 auto-direction delays on any port.
Signed-off-by: Filip Brozovic <fbrozovic@gmail.com>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20241110111703.15494-1-fbrozovic@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 718632467d upstream.
This reverts commit 3791ea69a4.
It was reported to cause boot-time issues, so revert it for now.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Fixes: 3791ea69a4 ("serial: sh-sci: Clean sci_ports[0] after at earlycon exit")
Cc: stable <stable@kernel.org>
Cc: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3791ea69a4 upstream.
The early_console_setup() function initializes the sci_ports[0].port with
an object of type struct uart_port obtained from the object of type
struct earlycon_device received as argument by the early_console_setup().
It may happen that later, when the rest of the serial ports are probed,
the serial port that was used as earlycon (e.g., port A) to be mapped to a
different position in sci_ports[] and the slot 0 to be used by a different
serial port (e.g., port B), as follows:
sci_ports[0] = port A
sci_ports[X] = port B
In this case, the new port mapped at index zero will have associated data
that was used for earlycon.
In case this happens, after Linux boot, any access to the serial port that
maps on sci_ports[0] (port A) will block the serial port that was used as
earlycon (port B).
To fix this, add early_console_exit() that clean the sci_ports[0] at
earlycon exit time.
Fixes: 0b0cced19a ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20241106120118.1719888-4-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 635a9fca54 upstream.
Commit 7c0cca7c84 ("tty: ldisc: add sysctl to prevent autoloading of
ldiscs") introduces the tty_ldisc_autoload sysctl with the wrong
proc_handler. .extra1 and .extra2 parameters are set to avoid other values
thant SYSCTL_ZERO or SYSCTL_ONE to be set but proc_dointvec do not uses
them.
This commit fixes this by using proc_dointvec_minmax instead of
proc_dointvec.
Fixes: 7c0cca7c84 ("tty: ldisc: add sysctl to prevent autoloading of ldiscs")
Cc: stable <stable@kernel.org>
Signed-off-by: Nicolas Bouchinet <nicolas.bouchinet@ssi.gouv.fr>
Reviewed-by: Lin Feng <linf@wangsu.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20241112131357.49582-4-nicolas.bouchinet@clip-os.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drop the unnecessary "_sys" infix from the suspend PM ops.
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20241009145110.16847-10-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Serial drivers should not be dropping characters themselves, but at
least drop the unused 'drop' parameter from the receive handler for now.
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20241009145110.16847-9-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drop the unnecessary WARN() in case the TTY buffers are ever full in
favour of a rate limited dev_err() which doesn't kill the machine when
panic_on_warn is set.
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20241009145110.16847-8-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The receiver is supposed to be enabled in the startup() callback and not
in set_termios() which is called also during console setup.
This specifically avoids accepting input before the port has been opened
(and interrupts enabled), something which can also break the GENI
firmware (cancel fails and after abort, the "stale" counter handling
appears to be broken so that later input is not processed until twelve
chars have been received).
There also does not appear to be any need to keep the receiver disabled
while updating the port settings.
Since commit 6f3c3cafb1 ("serial: qcom-geni: disable interrupts during
console writes") the calls to manipulate the secondary interrupts, which
were done without holding the port lock, can also lead to the receiver
being left disabled when set_termios() races with the console code (e.g.
when init opens the tty during boot). This can manifest itself as a
serial getty not accepting input.
The calls to stop and start rx in set_termios() can similarly race with
DMA completion and, for example, cause the DMA buffer to be unmapped
twice or the mapping to be leaked.
Fix this by only enabling the receiver during startup and while holding
the port lock to avoid racing with the console code.
Fixes: 6f3c3cafb1 ("serial: qcom-geni: disable interrupts during console writes")
Fixes: 2aaa43c707 ("tty: serial: qcom-geni-serial: add support for serial engine DMA")
Fixes: c4f528795d ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
Cc: stable@vger.kernel.org # 6.3
Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20241009145110.16847-6-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make sure to wait for the DMA transfer to complete when cancelling the
rx command on stop_rx(). This specifically prevents the DMA completion
interrupt from firing after rx has been restarted, something which can
lead to an IOMMU fault and hosed rx when the interrupt handler unmaps
the DMA buffer for the new command:
qcom_geni_serial 988000.serial: serial engine reports 0 RX bytes in!
arm-smmu 15000000.iommu: FSR = 00000402 [Format=2 TF], SID=0x563
arm-smmu 15000000.iommu: FSYNR0 = 00210013 [S1CBNDX=33 WNR PLVL=3]
Bluetooth: hci0: command 0xfc00 tx timeout
Bluetooth: hci0: Reading QCA version information failed (-110)
Also add the missing state machine reset which is needed in case
cancellation fails.
Fixes: 2aaa43c707 ("tty: serial: qcom-geni-serial: add support for serial engine DMA")
Cc: stable@vger.kernel.org # 6.3
Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20241009145110.16847-5-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A commit adding back the stopping of tx on port shutdown failed to add
back the locking which had also been removed by commit e83766334f
("tty: serial: qcom_geni_serial: No need to stop tx/rx on UART
shutdown").
Holding the port lock is needed to serialise against the console code,
which may update the interrupt enable register and access the port
state.
Fixes: d8aca2f968 ("tty: serial: qcom-geni-serial: stop operations in progress at shutdown")
Fixes: 947cc4ecc0 ("serial: qcom-geni: fix soft lockup on sw flow control and suspend")
Cc: stable@vger.kernel.org # 6.3
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20241009145110.16847-4-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 35781d8356.
Hibernation is not supported on Qualcomm platforms with mainline
kernels yet a broken vendor implementation for the GENI serial driver
made it upstream.
This is effectively dead code that cannot be tested and should just be
removed, but if these paths were ever hit for an open non-console port
they would crash the machine as the driver would fail to enable clocks
during restore() (i.e. all ports would have to be closed by drivers and
user space before hibernating the system to avoid this as a comment in
the code hinted at).
The broken implementation also added a random call to enable the
receiver in the port setup code where it does not belong and which
enables the receiver prematurely for console ports.
Fixes: 35781d8356 ("tty: serial: qcom-geni-serial: Add support for Hibernation feature")
Cc: stable@vger.kernel.org # 6.2
Cc: Aniket Randive <quic_arandive@quicinc.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20241009145110.16847-3-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The polled console (KGDB/KDB) implementation must not call port setup
unconditionally as the port may already be in use by the console or a
getty.
Only make sure that the receiver is enabled, but do not enable any
device interrupts.
Fixes: d8851a96ba ("tty: serial: qcom-geni-serial: Add a poll_init() function")
Cc: stable@vger.kernel.org # 6.4
Cc: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20241009145110.16847-2-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When sending data using DMA at high baudrate (4 Mbdps in local test case) to
a device with small RX buffer which keeps asserting RTS after every received
byte, it is possible that the iMX UART driver would not recognize the falling
edge of RTS input signal and get stuck, unable to transmit any more data.
This condition happens when the following sequence of events occur:
- imx_uart_mctrl_check() is called at some point and takes a snapshot of UART
control signal status into sport->old_status using imx_uart_get_hwmctrl().
The RTSS/TIOCM_CTS bit is of interest here (*).
- DMA transfer occurs, the remote device asserts RTS signal after each byte.
The i.MX UART driver recognizes each such RTS signal change, raises an
interrupt with USR1 register RTSD bit set, which leads to invocation of
__imx_uart_rtsint(), which calls uart_handle_cts_change().
- If the RTS signal is deasserted, uart_handle_cts_change() clears
port->hw_stopped and unblocks the port for further data transfers.
- If the RTS is asserted, uart_handle_cts_change() sets port->hw_stopped
and blocks the port for further data transfers. This may occur as the
last interrupt of a transfer, which means port->hw_stopped remains set
and the port remains blocked (**).
- Any further data transfer attempts will trigger imx_uart_mctrl_check(),
which will read current status of UART control signals by calling
imx_uart_get_hwmctrl() (***) and compare it with sport->old_status .
- If current status differs from sport->old_status for RTS signal,
uart_handle_cts_change() is called and possibly unblocks the port
by clearing port->hw_stopped .
- If current status does not differ from sport->old_status for RTS
signal, no action occurs. This may occur in case prior snapshot (*)
was taken before any transfer so the RTS is deasserted, current
snapshot (***) was taken after a transfer and therefore RTS is
deasserted again, which means current status and sport->old_status
are identical. In case (**) triggered when RTS got asserted, and
made port->hw_stopped set, the port->hw_stopped will remain set
because no change on RTS line is recognized by this driver and
uart_handle_cts_change() is not called from here to unblock the
port->hw_stopped.
Update sport->old_status in __imx_uart_rtsint() accordingly to make
imx_uart_mctrl_check() detect such RTS change. Note that TIOCM_CAR
and TIOCM_RI bits in sport->old_status do not suffer from this problem.
Fixes: ceca629e0b ("[ARM] 2971/1: i.MX uart handle rts irq")
Cc: stable <stable@kernel.org>
Reviewed-by: Esben Haabendal <esben@geanix.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20241002184133.19427-1-marex@denx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
