[ Upstream commit a5fd8945a4 ]
Clear rx_running flag only after DMA teardown polling completes. In the
previous implementation the flag was being cleared while hardware teardown
was still in progress, creating a mismatch between software state
(flag = 0, "ready") and hardware state (still terminating).
Signed-off-by: Moteen Shah <m-shah@ti.com>
Link: https://patch.msgid.link/20260112081829.63049-3-m-shah@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 623b07b370 ]
The DMA IRQ handler does not accounts for the overrun(OE) or any other
errors being reported by the IP before triggering a DMA transaction which
leads to the interrupts not being handled resulting into an IRQ storm.
The way to handle OE is to:
1. Reset the RX FIFO.
2. Read the UART_RESUME register, which clears the internal flag
Earlier, the driver issued DMA transations even in case of OE which shouldn't
be done according to the OE handling mechanism mentioned above, as we are
resetting the FIFO's, refer section: "12.1.6.4.8.1.3.6 Overrun During
Receive" [0].
[0] https://www.ti.com/lit/pdf/spruiu1
Signed-off-by: Moteen Shah <m-shah@ti.com>
Link: https://patch.msgid.link/20260112081829.63049-2-m-shah@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d31228143a ]
Add error checking for clk_prepare_enable() calls in
dw8250_runtime_resume(). Currently if either clock fails to enable,
the function returns success while leaving clocks in inconsistent state.
This change implements comprehensive error handling by checking the return
values of both clk_prepare_enable() calls. If the second clock enable
operation fails after the first clock has already been successfully
enabled, the code now properly cleans up by disabling and unpreparing
the first clock before returning. The error code is then propagated to
the caller, ensuring that clock enable failures are properly reported
rather than being silently ignored.
Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
Link: https://patch.msgid.link/20251104145433.2316165-2-a.shimko.dev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 27aff0a56b upstream.
Fintek F81504/508/512 can support both RTS_ON_SEND and RTS_AFTER_SEND,
but pci_fintek_rs485_supported only announces the former.
This makes it impossible to unset SER_RS485_RTS_ON_SEND from
userspace because of uart_sanitize_serial_rs485(). Some devices
with these chips need RTS low on TX, so they are effectively broken.
Fix this by announcing the support for SER_RS485_RTS_AFTER_SEND,
similar to commit 068d35a7be ("serial: sc16is7xx: announce support
for SER_RS485_RTS_ON_SEND").
Fixes: 4afeced55b ("serial: core: fix sanitizing check for RTS settings")
Cc: stable <stable@kernel.org>
Signed-off-by: Marnix Rijnart <marnix.rijnart@iwell.eu>
Link: https://patch.msgid.link/20260112000931.61703-1-marnix.rijnart@iwell.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 267ee93c41 ]
RTS line control with delay should be triggered when there is no more
bytes in kfifo and hardware buffer is empty. Without this patch RTS
control is scheduled right after feeding hardware buffer and this is too
early.
RTS line may change state before hardware buffer is empty.
With this patch delayed RTS state change is triggered when function
cdns_uart_handle_tx is called from cdns_uart_isr on
CDNS_UART_IXR_TXEMPTY exactly when hardware completed transmission
Fixes: fccc9d9233 ("tty: serial: uartps: Add rs485 support to uartps driver")
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20251221103221.1971125-1-jakub.turek@elsta.tech
Signed-off-by: Jakub Turek <jakub.turek@elsta.tech>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c3ca8a0aac upstream.
The driver updates struct sci_port::tx_cookie to zero right before the TX
work is scheduled, or to -EINVAL when DMA is disabled.
dma_async_is_complete(), called through dma_cookie_status() (and possibly
through dmaengine_tx_status()), considers cookies valid only if they have
values greater than or equal to 1.
Passing zero or -EINVAL to dmaengine_tx_status() before any TX DMA
transfer has started leads to an incorrect TX status being reported, as the
cookie is invalid for the DMA subsystem. This may cause long wait times
when the serial device is opened for configuration before any TX activity
has occurred.
Check that the TX cookie is valid before passing it to
dmaengine_tx_status().
Fixes: 7cc0e0a43a ("serial: sh-sci: Check if TX data was written to device in .tx_empty()")
Cc: stable <stable@kernel.org>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/20251217135759.402015-1-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 29e8a0c587 ]
In sprd_clk_init(), when devm_clk_get() returns -EPROBE_DEFER
for either uart or source clock, we should propagate the
error instead of just warning and continuing with NULL clocks.
Currently the driver only emits a warning when clock acquisition
fails and proceeds with NULL clock pointers. This can lead to
issues later when the clocks are actually needed. More importantly,
when the clock provider is not ready yet and returns -EPROBE_DEFER,
we should return this error to allow deferred probing.
This change adds explicit checks for -EPROBE_DEFER after both:
1. devm_clk_get(uport->dev, uart)
2. devm_clk_get(uport->dev, source)
When -EPROBE_DEFER is encountered, the function now returns
-EPROBE_DEFER to let the driver framework retry probing
later when the clock dependencies are resolved.
Signed-off-by: Wenhua Lin <Wenhua.Lin@unisoc.com>
Link: https://patch.msgid.link/20251022030840.956589-1-Wenhua.Lin@unisoc.com
Reviewed-by: Cixi Geng <cixi.geng@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit eb4917f557 upstream.
Check for returned DMA addresses using specialized dma_mapping_error()
helper which is generally recommended for this purpose by
Documentation/core-api/dma-api.rst:
"In some circumstances dma_map_single(), ...
will fail to create a mapping. A driver can check for these errors
by testing the returned DMA address with dma_mapping_error()."
Found via static analysis and this is similar to commit fa0308134d
("ALSA: memalloc: prefer dma_mapping_error() over explicit address checking")
Fixes: 58ac1b3799 ("ARM: PL011: Fix DMA support")
Cc: stable <stable@kernel.org>
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://patch.msgid.link/20251027092053.87937-1-linmq006@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1c05bf6c02 upstream.
Commit 43c51bb573 ("sc16is7xx: make sure device is in suspend once
probed") permanently enabled access to the enhanced features in
sc16is7xx_probe(), and it is never disabled after that.
Therefore, remove re-enable of enhanced features in
sc16is7xx_set_baud(). This eliminates a potential useless read + write
cycle each time the baud rate is reconfigured.
Fixes: 43c51bb573 ("sc16is7xx: make sure device is in suspend once probed")
Cc: stable <stable@kernel.org>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://patch.msgid.link/20251006142002.177475-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d518314a1f upstream.
Some MediaTek SoCs got a gated UART baud clock, which currently gets
disabled as the clk subsystem believes it would be unused. This results in
the uart freezing right after "clk: Disabling unused clocks" on those
platforms.
Request the baud clock to be prepared and enabled during probe, and to
restore run-time power management capabilities to what it was before commit
e32a83c70c ("serial: 8250-mtk: modify mtk uart power and clock
management") disable and unprepare the baud clock when suspending the UART,
prepare and enable it again when resuming it.
Fixes: e32a83c70c ("serial: 8250-mtk: modify mtk uart power and clock management")
Fixes: b6c7ff2693 ("serial: 8250_mtk: Simplify clock sequencing and runtime PM")
Cc: stable <stable@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://patch.msgid.link/de5197ccc31e1dab0965cabcc11ca92e67246cf6.1758058441.git.daniel@makrotopia.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit daeb4037ad upstream.
Check the return value of reset_control_deassert() in the probe
function to prevent continuing probe when reset deassertion fails.
Previously, reset_control_deassert() was called without checking its
return value, which could lead to probe continuing even when the
device reset wasn't properly deasserted.
The fix checks the return value and returns an error with dev_err_probe()
if reset deassertion fails, providing better error handling and
diagnostics.
Fixes: acbdad8dd1 ("serial: 8250_dw: simplify optional reset handling")
Cc: stable <stable@kernel.org>
Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
Link: https://patch.msgid.link/20251019095131.252848-1-a.shimko.dev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 535fd4c984 upstream.
When trying to set MCR[2], XON1 is incorrectly accessed instead. And when
writing to the TCR register to configure flow control levels, we are
incorrectly writing to the MSR register. The default value of $00 is then
used for TCR, which means that selectable trigger levels in FCR are used
in place of TCR.
TCR/TLR access requires EFR[4] (enable enhanced functions) and MCR[2]
to be set. EFR[4] is already set in probe().
MCR access requires LCR[7] to be zero.
Since LCR is set to $BF when trying to set MCR[2], XON1 is incorrectly
accessed instead because MCR shares the same address space as XON1.
Since MCR[2] is unmodified and still zero, when writing to TCR we are in
fact writing to MSR because TCR/TLR registers share the same address space
as MSR/SPR.
Fix by first removing useless reconfiguration of EFR[4] (enable enhanced
functions), as it is already enabled in sc16is7xx_probe() since commit
43c51bb573 ("sc16is7xx: make sure device is in suspend once probed").
Now LCR is $00, which means that MCR access is enabled.
Also remove regcache_cache_bypass() calls since we no longer access the
enhanced registers set, and TCR is already declared as volatile (in fact
by declaring MSR as volatile, which shares the same address).
Finally disable access to TCR/TLR registers after modifying them by
clearing MCR[2].
Note: the comment about "... and internal clock div" is wrong and can be
ignored/removed as access to internal clock div registers (DLL/DLH)
is permitted only when LCR[7] is logic 1, not when enhanced features
is enabled. And DLL/DLH access is not needed in sc16is7xx_startup().
Fixes: dfeae619d7 ("serial: sc16is7xx")
Cc: stable@vger.kernel.org
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20250731124451.1108864-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7f8fdd4dbf upstream.
When the PSLVERR_RESP_EN parameter is set to 1, the device generates
an error response if an attempt is made to read an empty RBR (Receive
Buffer Register) while the FIFO is enabled.
In serial8250_do_startup(), calling serial_port_out(port, UART_LCR,
UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes
dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter
function enables the FIFO via serial_out(p, UART_FCR, p->fcr).
Execution proceeds to the serial_port_in(port, UART_RX).
This satisfies the PSLVERR trigger condition.
When another CPU (e.g., using printk()) is accessing the UART (UART
is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) ==
(lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter
dw8250_force_idle().
Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock
to fix this issue.
Panic backtrace:
[ 0.442336] Oops - unknown exception [#1]
[ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a
[ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e
...
[ 0.442416] console_on_rootfs+0x26/0x70
Fixes: c49436b657 ("serial: 8250_dw: Improve unwritable LCR workaround")
Link: https://lore.kernel.org/all/84cydt5peu.fsf@jogness.linutronix.de/T/
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20250723023322.464-2-cuiyunhui@bytedance.com
[ adapted to inline code structure without separate serial8250_initialize helper function ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 33a2515abd ]
The serial info sometimes produces negative TX/RX counts. E.g.:
3: uart:FSL_LPUART mmio:0x02970000 irq:46 tx:-1595870545 rx:339619
RTS|CTS|DTR|DSR|CD
It appears that the print format specifiers don't match with the types of
the respective variables. E.g.: All of the fields in struct uart_icount
are u32, but the format specifier used is %d, even though u32 is unsigned
and %d is for signed integers. Update drivers/tty/serial/serial_core.c
to use the proper format specifiers. Reference
https://docs.kernel.org/core-api/printk-formats.html as the documentation
for what format specifiers are the proper ones to use for a given C type.
Signed-off-by: Joseph Tilahun <jtilahun@astranis.com>
Link: https://lore.kernel.org/r/20250610065653.3750067-1-jtilahun@astranis.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit f23c52aafb upstream.
Commit 7a637784d5 ("serial: imx: reduce RX interrupt frequency")
introduced a regression on the i.MX6UL EVK board. The issue can be
reproduced with the following steps:
- Open vi on the board.
- Paste a text file (~150 characters).
- Save the file, then repeat the process.
- Compare the sha256sum of the saved files.
The checksums do not match due to missing characters or entire lines.
Fix this by restoring the RXTL value to 1 when the UART is used as a
console.
This ensures timely RX interrupts and reliable data reception in console
mode.
With this change, pasted content is saved correctly, and checksums are
always consistent.
Cc: stable <stable@kernel.org>
Fixes: 7a637784d5 ("serial: imx: reduce RX interrupt frequency")
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20250619114617.2791939-1-festevam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d36f0e9a00 upstream.
Since in v6.8-rc1, the of_node symlink under tty devices is
missing. This breaks any udev rules relying on this information.
Link the of_node information in the serial controller device with the
parent defined in the device tree. This will also apply to the serial
device which takes the serial controller as a parent device.
Fixes: b286f4e87e ("serial: core: Move tty and serdev to be children of serial core port device")
Cc: stable@vger.kernel.org
Signed-off-by: Aidan Stewart <astewart@tektelic.com>
Link: https://lore.kernel.org/r/20250617164819.13912-1-astewart@tektelic.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 6bd697b5fc ]
When two instances of uart devices are probing, a concurrency race can
occur. If one thread calls uart_register_driver function, which first
allocates and assigns memory to 'uart_state' member of uart_driver
structure, the other instance can bypass uart driver registration and
call ulite_assign. This calls uart_add_one_port, which expects the uart
driver to be fully initialized. This leads to a kernel panic due to a
null pointer dereference:
[ 8.143581] BUG: kernel NULL pointer dereference, address: 00000000000002b8
[ 8.156982] #PF: supervisor write access in kernel mode
[ 8.156984] #PF: error_code(0x0002) - not-present page
[ 8.156986] PGD 0 P4D 0
...
[ 8.180668] RIP: 0010:mutex_lock+0x19/0x30
[ 8.188624] Call Trace:
[ 8.188629] ? __die_body.cold+0x1a/0x1f
[ 8.195260] ? page_fault_oops+0x15c/0x290
[ 8.209183] ? __irq_resolve_mapping+0x47/0x80
[ 8.209187] ? exc_page_fault+0x64/0x140
[ 8.209190] ? asm_exc_page_fault+0x22/0x30
[ 8.209196] ? mutex_lock+0x19/0x30
[ 8.223116] uart_add_one_port+0x60/0x440
[ 8.223122] ? proc_tty_register_driver+0x43/0x50
[ 8.223126] ? tty_register_driver+0x1ca/0x1e0
[ 8.246250] ulite_probe+0x357/0x4b0 [uartlite]
To prevent it, move uart driver registration in to init function. This
will ensure that uart_driver is always registered when probe function
is called.
Signed-off-by: Jakub Lewalski <jakub.lewalski@nokia.com>
Signed-off-by: Elodie Decerle <elodie.decerle@nokia.com>
Link: https://lore.kernel.org/r/20250331160732.2042-1-elodie.decerle@nokia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c40b91e38e ]
Systems that issue PCIe hot reset requests during a suspend/resume
cycle cause PCI1XXXX device revisions prior to C0 to get its UART
configuration registers reset to hardware default values. This results
in device inaccessibility and data transfer failures. Starting with
Revision C0, support was added in the device hardware (via the Hot
Reset Disable Bit) to allow resetting only the PCIe interface and its
associated logic, but preserving the UART configuration during a hot
reset. This patch enables the hot reset disable feature during suspend/
resume for C0 and later revisions of the device.
Signed-off-by: Rengarajan S <rengarajan.s@microchip.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250425145500.29036-1-rengarajan.s@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 651dee0369 upstream.
In the sh-sci driver, serial ports are mapped to the sci_ports[] array,
with earlycon mapped at index zero.
The uart_add_one_port() function eventually calls __device_attach(),
which, in turn, calls pm_request_idle(). The identified code path is as
follows:
uart_add_one_port() ->
serial_ctrl_register_port() ->
serial_core_register_port() ->
serial_core_port_device_add() ->
serial_base_port_add() ->
device_add() ->
bus_probe_device() ->
device_initial_probe() ->
__device_attach() ->
// ...
if (dev->p->dead) {
// ...
} else if (dev->driver) {
// ...
} else {
// ...
pm_request_idle(dev);
// ...
}
The earlycon device clocks are enabled by the bootloader. However, the
pm_request_idle() call in __device_attach() disables the SCI port clocks
while earlycon is still active.
The earlycon write function, serial_console_write(), calls
sci_poll_put_char() via serial_console_putchar(). If the SCI port clocks
are disabled, writing to earlycon may sometimes cause the SR.TDFE bit to
remain unset indefinitely, causing the while loop in sci_poll_put_char()
to never exit. On single-core SoCs, this can result in the system being
blocked during boot when this issue occurs.
To resolve this, increment the runtime PM usage counter for the earlycon
SCI device before registering the UART port.
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/20250116182249.3828577-6-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5f10170699 upstream.
The early_console_setup() function initializes sci_ports[0].port with an
object of type struct uart_port obtained from the struct earlycon_device
passed as an argument to early_console_setup().
Later, during serial port probing, the serial port used as earlycon
(e.g., port A) might be remapped to a different position in the sci_ports[]
array, and a different serial port (e.g., port B) might be assigned to slot
0. For example:
sci_ports[0] = port B
sci_ports[X] = port A
In this scenario, the new port mapped at index zero (port B) retains the
data associated with the earlycon configuration. Consequently, after the
Linux boot process, any access to the serial port now mapped to
sci_ports[0] (port B) will block the original earlycon port (port A).
To address this, introduce an early_console_exit() function to clean up
sci_ports[0] when earlycon is exited.
To prevent the cleanup of sci_ports[0] while the serial device is still
being used by earlycon, introduce the struct sci_port::probing flag and
account for it in early_console_exit().
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/20250116182249.3828577-5-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b495021a97 upstream.
Commit 1788cf6a91 ("tty: serial: switch from circ_buf to kfifo")
introduced an error in the TX DMA handling for 8250_omap.
When the OMAP_DMA_TX_KICK flag is set, the "skip_byte" is pulled from
the kfifo and emitted directly in order to start the DMA. While the
kfifo is updated, dma->tx_size is not decreased. This leads to
uart_xmit_advance() called in omap_8250_dma_tx_complete() advancing the
kfifo by one too much.
In practice, transmitting N bytes has been seen to result in the last
N-1 bytes being sent repeatedly.
This change fixes the problem by moving all of the dma setup after the
OMAP_DMA_TX_KICK handling and using kfifo_len() instead of the DMA size
for the 4-byte cutoff check. This slightly changes the behaviour at
buffer wraparound, but it still transmits the correct bytes somehow.
Now, the "skip_byte" would no longer be accounted to the stats. As
previously, dma->tx_size included also this skip byte, up->icount.tx was
updated by aforementioned uart_xmit_advance() in
omap_8250_dma_tx_complete(). Fix this by using the uart_fifo_out()
helper instead of bare kfifo_get().
Based on patch by Mans Rullgard <mans@mansr.com>
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Fixes: 1788cf6a91 ("tty: serial: switch from circ_buf to kfifo")
Link: https://lore.kernel.org/all/20250506150748.3162-1-mans@mansr.com/
Reported-by: Mans Rullgard <mans@mansr.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250522053835.3495975-1-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 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>
[ 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>
