DW UART cannot write to LCR, DLL, and DLH while BUSY is asserted.
Existance of BUSY depends on uart_16550_compatible, if UART HW is
configured with it those registers can always be written.
There currently is dw8250_force_idle() which attempts to achieve
non-BUSY state by disabling FIFO, however, the solution is unreliable
when Rx keeps getting more and more characters.
Create a sequence of operations that ensures UART cannot keep BUSY
asserted indefinitely. The new sequence relies on enabling loopback mode
temporarily to prevent incoming Rx characters keeping UART BUSY.
Ensure no Tx in ongoing while the UART is switches into the loopback
mode (requires exporting serial8250_fifo_wait_for_lsr_thre() and adding
DMA Tx pause/resume functions).
According to tests performed by Adriana Nicolae <adriana@arista.com>,
simply disabling FIFO or clearing FIFOs only once does not always
ensure BUSY is deasserted but up to two tries may be needed. This could
be related to ongoing Rx of a character (a guess, not known for sure).
Therefore, retry FIFO clearing a few times (retry limit 4 is arbitrary
number but using, e.g., p->fifosize seems overly large). Tests
performed by others did not exhibit similar challenge but it does not
seem harmful to leave the FIFO clearing loop in place for all DW UARTs
with BUSY functionality.
Use the new dw8250_idle_enter/exit() to do divisor writes and LCR
writes. In case of plain LCR writes, opportunistically try to update
LCR first and only invoke dw8250_idle_enter() if the write did not
succeed (it has been observed that in practice most LCR writes do
succeed without complications).
This issue was first reported by qianfan Zhao who put lots of debugging
effort into understanding the solution space.
Fixes: c49436b657 ("serial: 8250_dw: Improve unwritable LCR workaround")
Fixes: 7d4008ebb1 ("tty: add a DesignWare 8250 driver")
Cc: stable <stable@kernel.org>
Reported-by: qianfan Zhao <qianfanguijin@163.com>
Link: https://lore.kernel.org/linux-serial/289bb78a-7509-1c5c-2923-a04ed3b6487d@163.com/
Reported-by: Adriana Nicolae <adriana@arista.com>
Link: https://lore.kernel.org/linux-serial/20250819182322.3451959-1-adriana@arista.com/
Reported-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Murthy, Shanth <shanth.murthy@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260203171049.4353-8-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When DW UART is !uart_16550_compatible, it can indicate BUSY at any
point (when under constant Rx pressure) unless a complex sequence of
steps is performed. Any LCR write can run a foul with the condition
that prevents writing LCR while the UART is BUSY, which triggers
BUSY_DETECT interrupt that seems unmaskable using IER bits.
Normal flow is that dw8250_handle_irq() handles BUSY_DETECT condition
by reading USR register. This BUSY feature, however, breaks the
assumptions made in serial8250_do_shutdown(), which runs
synchronize_irq() after clearing IER and assumes no interrupts can
occur after that point but then proceeds to update LCR, which on DW
UART can trigger an interrupt.
If serial8250_do_shutdown() releases the interrupt handler before the
handler has run and processed the BUSY_DETECT condition by read the USR
register, the IRQ is not deasserted resulting in interrupt storm that
triggers "irq x: nobody cared" warning leading to disabling the IRQ.
Add late synchronize_irq() into serial8250_do_shutdown() to ensure
BUSY_DETECT from DW UART is handled before port's interrupt handler is
released. Alternative would be to add DW UART specific shutdown
function but it would mostly duplicate the generic code and the extra
synchronize_irq() seems pretty harmless in serial8250_do_shutdown().
Fixes: 7d4008ebb1 ("tty: add a DesignWare 8250 driver")
Cc: stable <stable@kernel.org>
Reported-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Murthy, Shanth <shanth.murthy@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260203171049.4353-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
INTC10EE UART can end up into an interrupt storm where it reports
IIR_NO_INT (0x1). If the storm happens during active UART operation, it
is promptly stopped by IIR value change due to Rx or Tx events.
However, when there is no activity, either due to idle serial line or
due to specific circumstances such as during shutdown that writes
IER=0, there is nothing to stop the storm.
During shutdown the storm is particularly problematic because
serial8250_do_shutdown() calls synchronize_irq() that will hang in
waiting for the storm to finish which never happens.
This problem can also result in triggering a warning:
irq 45: nobody cared (try booting with the "irqpoll" option)
[...snip...]
handlers:
serial8250_interrupt
Disabling IRQ #45
Normal means to reset interrupt status by reading LSR, MSR, USR, or RX
register do not result in the UART deasserting the IRQ.
Add a quirk to INTC10EE UARTs to enable Tx interrupts if UART's Tx is
currently empty and inactive. Rework IIR_NO_INT to keep track of the
number of consecutive IIR_NO_INT, and on fourth one perform the quirk.
Enabling Tx interrupts should change IIR value from IIR_NO_INT to
IIR_THRI which has been observed to stop the storm.
Fixes: e92fad0249 ("serial: 8250_dw: Add ACPI ID for Granite Rapids-D UART")
Cc: stable <stable@kernel.org>
Reported-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Murthy, Shanth <shanth.murthy@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260203171049.4353-6-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
dw8250_handle_irq() takes port's lock multiple times with no good
reason to release it in between and calls serial8250_handle_irq()
that also takes port's lock.
Take port's lock only once in dw8250_handle_irq() and use
serial8250_handle_irq_locked() to avoid releasing port's lock in
between.
As IIR_NO_INT check in serial8250_handle_irq() was outside of port's
lock, it has to be done already in dw8250_handle_irq().
DW UART can, in addition to IIR_NO_INT, report BUSY_DETECT (0x7) which
collided with the IIR_NO_INT (0x1) check in serial8250_handle_irq()
(because & is used instead of ==) meaning that no other work is done by
serial8250_handle_irq() during an BUSY_DETECT interrupt.
This allows reorganizing code in dw8250_handle_irq() to do both
IIR_NO_INT and BUSY_DETECT handling right at the start simplifying
the logic.
Tested-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Murthy, Shanth <shanth.murthy@intel.com>
Cc: stable <stable@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260203171049.4353-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
8250_port exports serial8250_handle_irq() to HW specific 8250 drivers.
It takes port's lock within but a HW specific 8250 driver may want to
take port's lock itself, do something, and then call the generic
handler in 8250_port but to do that, the caller has to release port's
lock for no good reason.
Introduce serial8250_handle_irq_locked() which a HW specific driver can
call while already holding port's lock.
As this is new export, put it straight into a namespace (where all 8250
exports should eventually be moved).
Tested-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Murthy, Shanth <shanth.murthy@intel.com>
Cc: stable <stable@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260203171049.4353-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When DW UART is configured with BUSY flag, LCR writes may not always
succeed which can make any LCR write complex and very expensive.
Performing write directly can trigger IRQ and the driver has to perform
complex and distruptive sequence while retrying the write.
Therefore, it's better to avoid doing LCR write that would not change
the value of the LCR register. Add LCR write avoidance code into the
8250_dw driver's .serial_out() functions.
Reported-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Murthy, Shanth <shanth.murthy@intel.com>
Cc: stable <stable@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260203171049.4353-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The 8250_dw driver needs to potentially perform very complex operations
during LCR writes because its BUSY handling prevents updates to LCR
while UART is BUSY (which is not fully under our control without those
complex operations). Thus, LCR writes should occur under port's lock.
Move LCR write under port's lock in serial8250_do_shutdown(). Also
split the LCR RMW so that the logic is on a separate line for clarity.
Reported-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Murthy, Shanth <shanth.murthy@intel.com>
Cc: stable <stable@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260203171049.4353-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is found in popular brands such as StarTech.com or Delock, and has
been a source of frustration to quite a few people, if I can trust
Amazon comments complaining about Linux support via the official
out-of-the-tree driver.
Signed-off-by: Martin Roukala (né Peres) <martin.roukala@mupuf.org>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20260309-8250_pci_ax99100-v1-1-3328bdfd8e94@mupuf.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uart_write_room() and uart_write() behave inconsistently when
xmit_buf is NULL (which happens for PORT_UNKNOWN ports that were
never properly initialized):
- uart_write_room() returns kfifo_avail() which can be > 0
- uart_write() checks xmit_buf and returns 0 if NULL
This inconsistency causes an infinite loop in drivers that rely on
tty_write_room() to determine if they can write:
while (tty_write_room(tty) > 0) {
written = tty->ops->write(...);
// written is always 0, loop never exits
}
For example, caif_serial's handle_tx() enters an infinite loop when
used with PORT_UNKNOWN serial ports, causing system hangs.
Fix by making uart_write_room() also check xmit_buf and return 0 if
it's NULL, consistent with uart_write().
Reproducer: https://gist.github.com/mrpre/d9a694cc0e19828ee3bc3b37983fde13
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20260204074327.226165-1-jiayuan.chen@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ulite_probe() calls pm_runtime_put_autosuspend() at the end of probe
without holding a corresponding PM runtime reference for non-console
ports.
During ulite_assign(), uart_add_one_port() triggers uart_configure_port()
which calls ulite_pm() via uart_change_pm(). For non-console ports, the
UART core performs a balanced get/put cycle:
uart_change_pm(ON) -> ulite_pm() -> pm_runtime_get_sync() +1
uart_change_pm(OFF) -> ulite_pm() -> pm_runtime_put_autosuspend() -1
This leaves no spare reference for the pm_runtime_put_autosuspend() at
the end of probe. The PM runtime core prevents the count from actually
going below zero, and instead triggers a
"Runtime PM usage count underflow!" warning.
For console ports the bug is masked: the UART core skips the
uart_change_pm(OFF) call, so the UART core's unbalanced get happens to
pair with probe's trailing put.
Add pm_runtime_get_noresume() before pm_runtime_enable() to take an
explicit probe-owned reference that the trailing
pm_runtime_put_autosuspend() can release. This ensures a correct usage
count regardless of whether the port is a console.
Fixes: 5bbe10a694 ("tty: serial: uartlite: Add runtime pm support")
Cc: stable <stable@kernel.org>
Signed-off-by: Maciej Andrzejewski ICEYE <maciej.andrzejewski@m-works.net>
Link: https://patch.msgid.link/20260305123746.4152800-1-maciej.andrzejewski@m-works.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 039d492637 ("serial: 8250: Toggle IER bits on only after irq
has been set up") moved IRQ setup before the THRE test, in combination
with commit 205d300aea ("serial: 8250: change lock order in
serial8250_do_startup()") the interrupt handler can run during the
test and race with its IIR reads. This can produce wrong THRE test
results and cause spurious registration of the
serial8250_backup_timeout timer. Unconditionally disable the IRQ for
the short duration of the test and re-enable it afterwards to avoid
the race.
Fixes: 039d492637 ("serial: 8250: Toggle IER bits on only after irq has been set up")
Depends-on: 205d300aea ("serial: 8250: change lock order in serial8250_do_startup()")
Cc: stable <stable@kernel.org>
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Alban Bedel <alban.bedel@lht.dlh.de>
Tested-by: Maximilian Lueer <maximilian.lueer@lht.dlh.de>
Link: https://patch.msgid.link/20260224121639.579404-1-alban.bedel@lht.dlh.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`dmaengine_terminate_async` does not guarantee that the
`__dma_tx_complete` callback will run. The callback is currently the
only place where `dma->tx_running` gets cleared. If the transaction is
canceled and the callback never runs, then `dma->tx_running` will never
get cleared and we will never schedule new TX DMA transactions again.
This change makes it so we clear `dma->tx_running` after we terminate
the DMA transaction. This is "safe" because `serial8250_tx_dma_flush`
is holding the UART port lock. The first thing the callback does is also
grab the UART port lock, so access to `dma->tx_running` is serialized.
Fixes: 9e512eaaf8 ("serial: 8250: Fix fifo underflow on flush")
Cc: stable <stable@kernel.org>
Signed-off-by: Raul E Rangel <rrangel@google.com>
Link: https://patch.msgid.link/20260209135815.1.I16366ecb0f62f3c96fe3dd5763fcf6f3c2b4d8cd@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This converts some of the visually simpler cases that have been split
over multiple lines. I only did the ones that are easy to verify the
resulting diff by having just that final GFP_KERNEL argument on the next
line.
Somebody should probably do a proper coccinelle script for this, but for
me the trivial script actually resulted in an assertion failure in the
middle of the script. I probably had made it a bit _too_ trivial.
So after fighting that far a while I decided to just do some of the
syntactically simpler cases with variations of the previous 'sed'
scripts.
The more syntactically complex multi-line cases would mostly really want
whitespace cleanup anyway.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the exact same thing as the 'alloc_obj()' version, only much
smaller because there are a lot fewer users of the *alloc_flex()
interface.
As with alloc_obj() version, this was done entirely with mindless brute
force, using the same script, except using 'flex' in the pattern rather
than 'objs*'.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
Here is the small amount of tty and serial driver updates for 7.0-rc1.
Nothing major in here at all, just some driver updates and minor tweaks
and cleanups including:
- sh-sci serial driver updates
- 8250 driver updates
- attempt to make the tty ports have their own workqueue, but was
reverted after testing found it to have problems on some platforms.
This will probably come back for 7.1 after it has been reworked and
resubmitted
- other tiny tty driver changes
All of these have been in linux-next for a while with no reported
problems.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty / serial driver updates from Greg KH:
"Here is the small amount of tty and serial driver updates for 7.0-rc1.
Nothing major in here at all, just some driver updates and minor
tweaks and cleanups including:
- sh-sci serial driver updates
- 8250 driver updates
- attempt to make the tty ports have their own workqueue, but was
reverted after testing found it to have problems on some platforms.
This will probably come back for 7.1 after it has been reworked and
resubmitted
- other tiny tty driver changes
All of these have been in linux-next for a while with no reported
problems"
* tag 'tty-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (49 commits)
Revert "tty: tty_port: add workqueue to flip TTY buffer"
tty: tty_port: add workqueue to flip TTY buffer
serial: 8250_pci: Remove custom deprecated baud setting routine
serial: 8250_omap: Remove custom deprecated baud setting routine
dt-bindings: serial: renesas,scif: Document RZ/G3L SoC
serial: 8250: omap: set out-of-band wakeup if wakeup pinctrl exists
tty: hvc-iucv: Remove KMSG_COMPONENT macro
dt-bindings: serial: google,goldfish-tty: Convert to DT schema
dt-bindings: serial: sh-sci: Fold single-entry compatibles into enum
serial: 8250: 8250_omap.c: Clear DMA RX running status only after DMA termination is done
serial: 8250: 8250_omap.c: Add support for handling UART error conditions
serial: SH_SCI: improve "DMA support" prompt
serial: Kconfig: fix ordering of entries for menu display
serial: 8250: fix ordering of entries for menu display
serial: imx: change SERIAL_IMX_CONSOLE to bool
8250_men_mcb: drop unneeded MODULE_ALIAS
serial: men_z135_uart: drop unneeded MODULE_ALIAS
dt-bindings: serial: renesas,rsci: Document RZ/V2H(P) and RZ/V2N SoCs
serial: rsci: Convert to FIELD_MODIFY()
dt-bindings: serial: 8250: add SpacemiT K3 UART compatible
...
Use the linux/platform_data/pic32.h include instead of
asm/mach-pic32/pic32.h so that the asm variant can be dropped. This
is in preparation for allowing some drivers to be compiled on other
architectures with COMPILE_TEST enabled.
Signed-off-by: Brian Masney <bmasney@redhat.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
As comments mentioned this is old (and actually deprecated) interface
to set custom baud rates. This interface has limitations as it only
allows to set a single opaque value called "custom_divisor". If the HW
needs more complex settings (like fractional divisor) it must somehow
encode this. This is horrid interface that is very driver specific
and not flexible. Meanwhile Linux has established way to set free
baud rate settings via BOTHER [1]. With all this being said, remove
deprecated interface for good.
Link: https://stackoverflow.com/questions/12646324/how-can-i-set-a-custom-baud-rate-on-linux [1]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260122102349.2395423-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As comments mentioned this is old (and actually deprecated) interface
to set custom baud rates. This interface has limitations as it only
allows to set a single opaque value called "custom_divisor". If the HW
needs more complex settings (like fractional divisor) it must somehow
encode this. This is horrid interface that is very driver specific
and not flexible. Meanwhile Linux has established way to set free
baud rate settings via BOTHER [1]. With all this being said, remove
deprecated interface for good.
Link: https://stackoverflow.com/questions/12646324/how-can-i-set-a-custom-baud-rate-on-linux [1]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260122102349.2395423-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In TI K3 SoCs, I/O daisy chaining is used to allow wakeup from UART when the
UART controller is off. Set UART device as wakeup capable using out-of-band
wakeup if the 'wakeup' pinctrl state exists and the device may wakeup.
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Kendall Willis <k-willis@ti.com>
Link: https://patch.msgid.link/20260116-uart-wakeup-v2-1-0078ae9996e4@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert commit bfc467db60 ("serial: remove redundant
tty_port_link_device()") because the tty_port_link_device() is not
redundant: the tty->port has to be confured before we call
uart_configure_port(), otherwise user-space can open console without TTY
linked to the driver.
This tty_port_link_device() was added explicitly to avoid this exact
issue in commit fb2b90014d ("tty: link tty and port before configuring
it as console"), so offending commit basically reverted the fix saying
it is redundant without addressing the actual race condition presented
there.
Reproducible always as tty->port warning on Qualcomm SoC with most of
devices disabled, so with very fast boot, and one serial device being
the console:
printk: legacy console [ttyMSM0] enabled
printk: legacy console [ttyMSM0] enabled
printk: legacy bootconsole [qcom_geni0] disabled
printk: legacy bootconsole [qcom_geni0] disabled
------------[ cut here ]------------
tty_init_dev: ttyMSM driver does not set tty->port. This would crash the kernel. Fix the driver!
WARNING: drivers/tty/tty_io.c:1414 at tty_init_dev.part.0+0x228/0x25c, CPU#2: systemd/1
Modules linked in: socinfo tcsrcc_eliza gcc_eliza sm3_ce fuse ipv6
CPU: 2 UID: 0 PID: 1 Comm: systemd Tainted: G S 6.19.0-rc4-next-20260108-00024-g2202f4d30aa8 #73 PREEMPT
Tainted: [S]=CPU_OUT_OF_SPEC
Hardware name: Qualcomm Technologies, Inc. Eliza (DT)
...
tty_init_dev.part.0 (drivers/tty/tty_io.c:1414 (discriminator 11)) (P)
tty_open (arch/arm64/include/asm/atomic_ll_sc.h:95 (discriminator 3) drivers/tty/tty_io.c:2073 (discriminator 3) drivers/tty/tty_io.c:2120 (discriminator 3))
chrdev_open (fs/char_dev.c:411)
do_dentry_open (fs/open.c:962)
vfs_open (fs/open.c:1094)
do_open (fs/namei.c:4634)
path_openat (fs/namei.c:4793)
do_filp_open (fs/namei.c:4820)
do_sys_openat2 (fs/open.c:1391 (discriminator 3))
...
Starting Network Name Resolution...
Apparently the flow with this small Yocto-based ramdisk user-space is:
driver (qcom_geni_serial.c): user-space:
============================ ===========
qcom_geni_serial_probe()
uart_add_one_port()
serial_core_register_port()
serial_core_add_one_port()
uart_configure_port()
register_console()
|
| open console
| ...
| tty_init_dev()
| driver->ports[idx] is NULL
|
tty_port_register_device_attr_serdev()
tty_port_link_device() <- set driver->ports[idx]
Fixes: bfc467db60 ("serial: remove redundant tty_port_link_device()")
Cc: stable@vger.kernel.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://patch.msgid.link/20260123072139.53293-2-krzysztof.kozlowski@oss.qualcomm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
Commit 10904d725f ("serial: qcom-geni: Enable PM runtime for serial
driver") caused BT init to fail during bootup on the RB2 platform,
preventing proper BT initialization. However, BT works correctly after
bootup completes.
The issue occurs when runtime PM is enabled and uart_add_one_port() is
called before wakeup IRQ setup. The uart_add_one_port() call activates
the device through runtime PM, which configures GPIOs to the "qup_x"
pinmux function during runtime resume. When wakeup IRQ registration
happens afterward using dev_pm_set_dedicated_wake_irq(), these GPIOs
are reset back to the "gpio" pinmux function, which impacts the RX GPIO
and leads to Bluetooth failures.
Fix this by ensuring wakeup IRQ setup is completed before calling
uart_add_one_port() to prevent the pinmux function conflict.
Fixes: 10904d725f ("serial: qcom-geni: Enable PM runtime for serial driver")
Reported-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Closes: https://lore.kernel.org/all/20251110101043.2108414-4-praveen.talari@oss.qualcomm.com/
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
Link: https://patch.msgid.link/20260108041006.1874757-1-praveen.talari@oss.qualcomm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
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>
Having a prompt of "DMA support" suddenly appear during a
"make oldconfig" can be confusing. Add a little helpful text to
the prompt message.
Fixes: 73a19e4c03 ("serial: sh-sci: Add DMA support.")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260110232643.3533351-5-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Improve the "Non-8250 serial port support" menu so that entries in it
are displayed in a better order (_CONSOLE after its driver) and so that
intervening symbols don't break up the dependency list, allowing menu
entries to be displayed with proper indentation.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://patch.msgid.link/20260110232643.3533351-4-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Improve the "8250/16550 serial support" menu so that entries in it
are displayed in a better order (reorder a few symbols) and so that
intervening symbols don't break up the dependency list, allowing menu
entries to be displayed with proper indentation.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://patch.msgid.link/20260110232643.3533351-3-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
SERIAL_IMX_CONSOLE is a build option for the imx driver (SERIAL_IMX).
It does not build a separate console driver file, so it can't be built
as a module since it isn't built at all.
Change the Kconfig symbol from tristate to bool and update the help
text accordingly.
Fixes: 0db4f9b91c ("tty: serial: imx: enable imx serial console port as module")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://patch.msgid.link/20260110232643.3533351-2-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since commit 1f4ea4838b ("mcb: Add missing modpost build support")
the MODULE_ALIAS() is redundant as the module alias is now
automatically generated from the MODULE_DEVICE_TABLE().
Remove the explicit alias.
No functional change intended.
Reviewed-by: Jorge Sanjuan Garcia <dev-jorge.sanjuangarcia@duagon.com>
Signed-off-by: Jose Javier Rodriguez Barbarin <dev-josejavier.rodriguez@duagon.com>
Link: https://patch.msgid.link/20260108134110.25278-3-dev-josejavier.rodriguez@duagon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since commit 1f4ea4838b ("mcb: Add missing modpost build support")
the MODULE_ALIAS() is redundant as the module alias is now
automatically generated from the MODULE_DEVICE_TABLE().
Remove the explicit alias.
No functional change intended.
Reviewed-by: Jorge Sanjuan Garcia <dev-jorge.sanjuangarcia@duagon.com>
Signed-off-by: Jose Javier Rodriguez Barbarin <dev-josejavier.rodriguez@duagon.com>
Link: https://patch.msgid.link/20260108134110.25278-2-dev-josejavier.rodriguez@duagon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
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>
During restoring sysfs fwnode information the information of_node_reused
was dropped. This was previously set by device_set_of_node_from_dev().
Add it back manually
Fixes: 24ec03cc55 ("serial: core: Restore sysfs fwnode information")
Cc: stable <stable@kernel.org>
Suggested-by: Cosmin Tanislav <demonsingur@gmail.com>
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Tested-by: Michael Walle <mwalle@kernel.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Cosmin Tanislav <demonsingur@gmail.com>
Link: https://patch.msgid.link/20251219152813.1893982-1-alexander.stein@ew.tq-group.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The devm_platform_get_and_ioremap_resource() function never returns
NULL, it returns error pointers. Fix the error checking to match.
Fixes: 25e95d7631 ("serial: 8250: Add Loongson uart driver support")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://patch.msgid.link/aSsIa3KdAlXh5uQC@stanley.mountain
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The change that restores sysfs fwnode information does it only for OF cases.
Update the fix to cover all possible types of fwnodes.
Fixes: d36f0e9a00 ("serial: core: restore of_node information in sysfs")
Cc: stable <stable@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20251127163650.2942075-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for RZ/G3E RSCI. RSCI IP found on the RZ/G3E SoC is similar
to RZ/T2H, but it has a 32-stage FIFO. It has 6 clocks(5 module clocks
+ 1 external clock) instead of 3 clocks(2 module clocks + 1 external
clock) on T2H, has 6 irqs compared to 4 on RZ/T2H and has multiple resets.
Add support for the hardware flow control.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20251129164325.209213-18-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rename rsci_early_console_setup()->rsci_rzt2h_early_console_setup(),
the early_console data of_sci_rsci_data->of_rsci_rzt2h_data and the
port_params rsci_port_params->rsci_rzt2h_port_params to support RZ/G3E
RSCI that uses different data and callback().
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20251129164325.209213-17-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add finish_console_write() callback as RZ/G3E RSCI IP needs special
handling compared to other SoCs.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20251129164325.209213-16-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make the function sci_scbrr_calc() public for code reuse to support RZ/G3E
RSCI IP.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20251129164325.209213-15-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The RZ/G3E RSCI IP has 32-stage FIFO compared to 16-stage FIFO on RZ/T2H.
Add RSCI_PORT_SCIF32 port ID to differentiate it from RZ/T2H RSCI and
update sci_is_rsci_type() and sci_is_fifo_type()
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20251129164325.209213-13-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rename port SCI_PORT_RSCI->RSCI_PORT_SCIF16 to differentiate it from
RZ/G3E port that has 32-stage FIFO.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20251129164325.209213-12-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add sci_is_rsci_type() for RSCI port type. This will simplify the code
when the support added for RSCI_PORT_SCIF32 private PORT type.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20251129164325.209213-11-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Replace devm_*_get_exclusive()->devm_*_array_get_exclusive() to support
existing SoCs along with RZ/G3E as RZ/G3E has 2 resets.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20251129164325.209213-10-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ilpo Järvinen
Martin Roukala (né Peres)
Jiayuan Chen
Maciej Andrzejewski ICEYE
Peng Zhang
Raul E Rangel
Kees Cook
Linus Torvalds
Brian Masney
Andy Shevchenko
Kendall Willis
Krzysztof Kozlowski
Marnix Rijnart
Praveen Talari
Moteen Shah
Randy Dunlap
Jose Javier Rodriguez Barbarin
Greg Kroah-Hartman
j.turek
Claudiu Beznea
Alexander Stein
Geert Uytterhoeven
Dan Carpenter
Biju Das