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path: root/drivers/tty/serial
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4 daysMerge tag 'tty-7.3-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull TTY / serial driver updates from Greg KH: "Here is the "big" set of tty and serial driver updates for 7.3-rc1. Not really all that much happened this development cycle for this subsystem, changes in here are: - removal of the ipwireless driver as it's no longer used or needed - new 8250_mxpcie driver added - qcom serial driver updates and additions - vt mode validation addition - lots of other small serial driver updates and additions All of these have been in linux-next for weeks with no reported issues" * tag 'tty-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (97 commits) serial: imx: serialize imx_uart_ports[] lifetime tty: clear cdev pointer after cdev_add() failure tty: skip cdev_del() when no cdev is registered serial: core: clear freed pointers on uart_register_driver() failure serial: core: do fallible allocations before the console can be registered serial: 8250_mxpcie: implement rx_trig_bytes callbacks via MUEx50 RTL serial: 8250_mxpcie: introduce per-port private data structure serial: 8250: allow UART drivers to override rx_trig_bytes handling serial: 8250_mxpcie: add break support for RS485 using MUEx50 features serial: 8250: allow low-level drivers to override break control serial: 8250_mxpcie: support serial interface mode switching serial: 8250_mxpcie: speed up TX using memory-mapped FIFO window serial: 8250_mxpcie: speed up RX using memory-mapped FIFO window serial: 8250_mxpcie: add custom handle_irq callback serial: 8250_mxpcie: offload XON/XOFF flow control to MUEx50 hardware serial: 8250_mxpcie: enable automatic RTS/CTS flow control serial: 8250_mxpcie: enable enhanced mode and program FIFO trigger levels serial: 8250: add Moxa MUEx50 UART port type serial: 8250: split Moxa PCIe serial board support out of 8250_pci serial: qcom-geni: Use geni_se_set_perf_level() for baud rate perf level ...
2026-08-03serial: imx: serialize imx_uart_ports[] lifetimeKarl Mehltretter
imx_uart_probe() publishes its devm-allocated port in imx_uart_ports[] before uart_add_one_port() because console setup uses the table. The entry is not cleared when adding the port fails or after removal, leaving a dangling pointer. A sibling probe can register the shared console through that stale entry. This was reproduced under KASAN on QEMU mcimx6ul-evk by unbinding a sibling UART, unbinding the console UART and rebinding the sibling. Keep the entry valid through uart_remove_one_port(), then clear it. Protect port addition and removal together with their table updates so sibling operations cannot interleave. Reject an occupied slot rather than clobbering an active port during a duplicate-line probe. Fixes: dbff4e9ea2e8 ("IMX UART: remove statically initialized tables") Fixes: 9f322ad064f9 ("imx: serial: handle initialisation failure correctly") Reported-by: Sashiko <sashiko-bot@kernel.org> Link: https://lore.kernel.org/all/20260719162850.043B41F000E9@smtp.kernel.org Link: https://lore.kernel.org/all/20260719222501.CB4CB1F000E9@smtp.kernel.org Cc: stable@vger.kernel.org Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Reviewed-by: Frank Li <Frank.Li@nxp.com> Link: https://patch.msgid.link/20260731181844.11330-6-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: core: clear freed pointers on uart_register_driver() failureKarl Mehltretter
uart_register_driver() leaves drv->state pointing to freed memory when tty_alloc_driver() fails. If tty_register_driver() fails, drv->tty_driver also retains a pointer after its reference is dropped. Drivers that use drv->state as an "already registered" flag can then skip registration on the next probe and pass the freed state to uart_add_one_port(). This issue was found with failslab on QEMU's raspi1ap board by failing registration and binding the PL011 port again. Clear both pointers on their failure paths, as uart_unregister_driver() already does. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Fixes: 9e845abfc8a8 ("serial: fix NULL pointer dereference") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Link: https://patch.msgid.link/20260731181844.11330-3-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: core: do fallible allocations before the console can be registeredKarl Mehltretter
serial_core_add_one_port() allocates uport->tty_groups after uart_configure_port(), which may register the console. If the allocation fails, the driver unwinds the port while its console remains registered. The earlier uport->name allocation has a related failure path that leaves state->uart_port linked to a port being freed. Failslab reproduced a NULL dereference in PL011 console output and a KASAN use-after-free in i.MX console output after failed binds. Allocate the name and tty_groups before linking the port and configuring it. Reserve space for the optional driver attribute group because config_port() may populate uport->attr_group during configuration. Fixes: 266dcff03eed ("Serial: allow port drivers to have a default attribute group") Fixes: f7048b15900f ("tty: serial_core: Add name field to uart_port struct") Reported-by: Sashiko <sashiko-bot@kernel.org> Closes: https://lore.kernel.org/all/20260719070454.D6FA21F000E9@smtp.kernel.org/ Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Link: https://patch.msgid.link/20260731181844.11330-2-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: implement rx_trig_bytes callbacks via MUEx50 RTLCrescent Hsieh
The MUEx50 UART exposes a programmable RX trigger level via the RTL register. Implement uart_port RX trigger set/get callbacks for the mxpcie driver and wire them up to the generic rx_trig_bytes sysfs interface. Store the configured trigger level in the per-port private data. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-15-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: introduce per-port private data structureCrescent Hsieh
Introduce a private per-port data structure for the mxpcie driver and replace the shared flexible array of registered lines with an array of per-port objects. This prepares the driver for storing per-port state needed by subsequent features. No functional change intended. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-14-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250: allow UART drivers to override rx_trig_bytes handlingCrescent Hsieh
The rx_trig_bytes sysfs attribute currently relies on 8250-internal helper functions and assumes a fixed mapping between trigger levels and FIFO behavior. Some UARTs provide hardware-specific RX trigger mechanisms that do not fit this model. Add optional uart_port callbacks for setting and getting the RX trigger level, and use them when provided, while preserving the existing 8250 helpers as the default fallback. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-13-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: add break support for RS485 using MUEx50 featuresCrescent Hsieh
On MUEx50, break signaling under RS485 requires a driver-specific sequence and cannot be handled correctly by the generic 8250 break implementation alone. Implement a mxpcie break_ctl callback that performs MUEx50-specific break handling when RS485 is enabled and fall back to the default 8250 break handling for other modes. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-12-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250: allow low-level drivers to override break controlCrescent Hsieh
Some UARTs require driver-specific handling for break signaling, which cannot be expressed by the generic 8250 break implementation alone. Add an optional uart_port break_ctl callback and route serial8250_break_ctl() through it when provided. Rename the existing 8250 implementation to serial8250_do_break_ctl() and export it so low-level drivers can reuse the default 8250 behavior when appropriate. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-11-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: support serial interface mode switchingCrescent Hsieh
Moxa PCIe multiport serial boards support switching the serial interface mode between RS232, RS422, RS485-2W, and RS485-4W via on-board control registers. Implement an rs485_config() callback and map TIOCSRS485 requests to the corresponding hardware modes using serial_rs485 flags: - RS232 = (no flags set) - RS422 = SER_RS485_ENABLED | SER_RS485_MODE_RS422 - RS485_2W (half-duplex) = SER_RS485_ENABLED - RS485_4W (full-duplex) = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX This allows users to reconfigure the serial mode at runtime via ioctl(). Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-10-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: speed up TX using memory-mapped FIFO windowCrescent Hsieh
The MUEx50 UART provides a memory-mapped TX FIFO data window along with a TX FIFO level counter. Fill the TX FIFO in bulk via the MMIO FIFO window based on available FIFO space, using uart_port_tx_limited() for the common serial-core TX handling. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-9-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: speed up RX using memory-mapped FIFO windowCrescent Hsieh
The MUEx50 UART provides a memory-mapped RX FIFO data window along with an RX FIFO byte counter. When no break or error conditions are present, read received data in bulk via the MMIO FIFO window and push it to the tty layer in one operation. Fall back to the generic 8250 RX path for break and error handling. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-8-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: add custom handle_irq callbackCrescent Hsieh
Add a mxpcie-specific handle_irq() implementation for Moxa PCIe serial ports. This keeps the interrupt handling self-contained in the driver and provides a hook point for MUEx50-specific RX/TX paths added in subsequent patches. The handler processes RX, updates modem status, and handles TX when THRE is asserted. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-7-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: offload XON/XOFF flow control to MUEx50 hardwareCrescent Hsieh
The MUEx50 UART can handle in-band software flow control (XON/XOFF) directly in hardware. Program the on-chip XON/XOFF characters from termios settings and enable the corresponding MUEx50 flow control modes when IXON or IXOFF is requested. Provide throttle and unthrottle callbacks so RX can be stopped and resumed cleanly. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-6-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: enable automatic RTS/CTS flow controlCrescent Hsieh
The MUEx50 UART supports automatic RTS/CTS flow control via the enhanced feature register. Implement a mxpcie-specific set_termios() callback that enables MUEx50 auto-RTS/auto-CTS when CRTSCTS is requested and disables it otherwise. Keep the 8250 port status flags in sync with the hardware configuration. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-5-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mxpcie: enable enhanced mode and program FIFO trigger levelsCrescent Hsieh
The MUEx50 UART provides an enhanced register set and programmable FIFO trigger levels for RX, TX, and flow control. Enable enhanced mode during port startup and program the MUEx50 FIFO trigger registers according to the configured port settings. Clear the programmed state again during shutdown to restore the default UART configuration. The TX FIFO write pointer and read pointer are driven by different clocks. Clear the FIFOs repeatedly during startup so both pointers are reset before programming the trigger levels. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-4-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250: add Moxa MUEx50 UART port typeCrescent Hsieh
Add a new 8250 port type for the Moxa MUEx50 UART and describe its basic FIFO size and trigger characteristics in the 8250 port configuration table. The 8250_mxpcie driver sets UPF_FIXED_TYPE and uses PORT_MUEX50 so that the generic 8250 core applies the correct defaults. Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Link: https://patch.msgid.link/20260731074820.735619-3-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250: split Moxa PCIe serial board support out of 8250_pciCrescent Hsieh
The Moxa PCIe multiport serial boards are currently handled as part of 8250_pci.c. In preparation for adding Moxa-specific UART features and optimizations, move the Moxa PCIe implementation into a dedicated driver. This introduces drivers/tty/serial/8250/8250_mxpcie.c and wires it up via Kconfig and Makefile, while preserving the existing probe flow and device IDs. This change was suggested during earlier reviews by Andy Shevchenko [1][2]. No functional change intended. Link: https://lore.kernel.org/all/ZmQovC6TbDpTb3c8@surfacebook.localdomain/ [1] Link: https://lore.kernel.org/all/CAHp75VeDsVt0GQYUFxLM+obfmqXBPa3hM3YMsFbc26uzWZG-SQ@mail.gmail.com/ [2] Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://patch.msgid.link/20260731074820.735619-2-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: qcom-geni: Use geni_se_set_perf_level() for baud rate perf levelPraveen Talari
The driver implements its own helper to select the performance level corresponding to a requested baud rate. The helper duplicates functionality already provided by geni_se_set_perf_level() in the GENI core. Replace the local implementation with the common helper and remove the associated duplicate definitions and code. This consolidates performance-level management in the GENI framework and reduces driver specific code. Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com> Link: https://patch.msgid.link/20260801-reuse_common_geni_framework_helpers-v2-3-13753256ef71@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: qcom-geni: Use resources helper APIs in runtime PM functionsPraveen Talari
To manage GENI serial engine resources during runtime power management, drivers currently need to call functions for ICC, clock, and SE resource operations in both suspend and resume paths, resulting in code duplication across drivers. The new geni_se_resources_activate() and geni_se_resources_deactivate() helper APIs addresses this issue by providing a streamlined method to enable or disable all resources based, thereby eliminating redundancy across drivers. Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com> Link: https://patch.msgid.link/20260801-reuse_common_geni_framework_helpers-v2-2-13753256ef71@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: qcom-geni: Use common GENI resource initialisation helpersPraveen Talari
The UART driver maintains local helpers for resource and power-domain initialisation that duplicate functionality already provided by the common GENI framework. Replace the driver-specific implementations with geni_se_resources_init() and geni_se_domain_attach(), and use the power-domain list stored in struct geni_se. This reduces code duplication and centralises GENI resource management without functional changes. Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com> Link: https://patch.msgid.link/20260801-reuse_common_geni_framework_helpers-v2-1-13753256ef71@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: amba-pl011: keep console clock enabled for atomic writesKarl Mehltretter
pl011_console_write_atomic() runs from nbcon atomic context, where sleeping is not allowed. It calls clk_enable(), which takes the common-clk enable_lock. Under PREEMPT_RT that is a sleeping lock: clk_enable_lock() first tries spin_trylock_irqsave(), but on contention falls back to spin_lock_irqsave(). Therefore, an atomic-context printk on an RT kernel with a clk-backed pl011 can trip: BUG: sleeping function called from invalid context at spinlock_rt.c:48 __might_resched from rt_spin_lock rt_spin_lock from clk_enable_lock clk_enable_lock from clk_enable clk_enable from pl011_console_write_atomic ... from vprintk_emit This was found and reproduced on PREEMPT_RT. Arm32 and arm64 DT SoCs are affected; arm64 SBSA/ACPI has no clk, so clk_enable(NULL) short-circuits before the lock. In addition, write_atomic() may be invoked from NMI context and is documented to avoid locking. Removing clk_enable() from the callback also avoids a potentially unsafe NMI acquisition of the common-clock enable_lock. An nbcon atomic-capable console must be printable from any context, so the clock cannot be gated between writes. Enable the clock while the console is available for output: use clk_prepare_enable() in pl011_console_setup(), release it via clk_disable_unprepare() in the console .exit() callback, and drop the per-write clk_enable()/clk_disable() pairs from write_atomic() and write_thread(). When printk suspends consoles, drop the reference after uart_suspend_port() stops console access and restore it before uart_resume_port() -- but only if suspend actually marked the port suspended (a wake-capable tty stays running and must keep its clock), and keep it when console_suspend_enabled is false so no_console_suspend works. The active power cost of keeping the clock enabled is platform-dependent: none where the UART clock is a fixed always-on oscillator, real where it is a gateable clock branch, which then cannot be gated (nor possibly can its parent clocks) while the console is available for output. When serial core actually suspends the port, the reference is released so the clock provider can gate the clock tree. Fixes: 2eb2608618ce ("serial: amba-pl011: Implement nbcon console") Suggested-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/all/8733xeaxix.fsf@jogness.linutronix.de/ Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Link: https://patch.msgid.link/20260724213348.77418-3-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: amba-pl011: unprepare console clock on unregisterKarl Mehltretter
pl011_console_setup() calls clk_prepare() on the UART clock, but the console provides no matching teardown, so the clock is never unprepared when the console is unregistered -- via the sysfs "console" attribute or a driver unbind. Each re-registration prepares the clock again, leaking one prepare reference per cycle. Even where preparing the clock has no hardware effect, the stale reference leaves the clock framework's prepare count unbalanced. For providers with prepare/unprepare operations or runtime-PM integration, it may also retain resources after the console is unregistered. Add a console .exit() callback that clk_unprepare()s the clock, balancing the clk_prepare() in pl011_console_setup(). Fixes: 4b4851c65d92 ("clk: amba-pl011: convert to clk_prepare()/clk_unprepare()") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Link: https://patch.msgid.link/20260724213348.77418-2-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_mtk: honor DT serial aliasesCarlo Caione
The Genio board DTs provide serial aliases for all enabled UARTs, but the MTK 8250 driver still registered every port with the default line number. If uart0 deferred and another UART probed first, the 8250 core could still assign ttyS0 to the wrong port despite the DT aliases. Read the serial alias during OF probe and seed uart.port.line before registering the port so the 8250 core reserves the requested ttyS slot. Signed-off-by: Carlo Caione <ccaione@baylibre.com> Reviewed-by: Chen-Yu Tsai <wenst@chromium.org> Link: https://patch.msgid.link/20260727-ccaione-genio-serial-aliases-v2-2-0f2ae41a8e89@baylibre.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: amba-pl011: synchronize DMA teardownFan Wu
dmaengine_terminate_all() does not wait for a running callback, so the TX callback can still touch the TX buffer after it is freed. The RX poll timer reads the RX buffers without the port lock. Switch to dmaengine_terminate_sync() and delete the RX timer before freeing the buffers. Fixes: ead76f329f77 ("ARM: 6763/1: pl011: add optional RX DMA to PL011 v2") Cc: stable <stable@kernel.org> Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu <fanwu01@zju.edu.cn> Link: https://patch.msgid.link/20260731085915.326775-4-fanwu01@zju.edu.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: amba-pl011: cancel RS485 hrtimers after freeing IRQFan Wu
The RS485 trigger hrtimers are embedded in the devm-managed port and can fire after it is freed. The IRQ handler can arm a timer, so free the IRQ first and then cancel both timers. Complete the RS485 stop without arming a timer, and cancel the timers in remove() for the suspend-then-unbind path, where shutdown is not called. This issue was found by an in-house static analysis tool. Fixes: 2c1fd53af21b ("serial: amba-pl011: Fix RTS handling in RS485 mode") Cc: stable <stable@kernel.org> Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu <fanwu01@zju.edu.cn> Link: https://patch.msgid.link/20260731085915.326775-3-fanwu01@zju.edu.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: amba-pl011: fix indefinite RS485 post-send delayFan Wu
The RS485 stop hrtimer is used both to drain the transmitter and to wait out delay_rts_after_send. The callback cannot tell the two apart, so it restarts the post-send delay on every expiry and the timer never stops. Add a WAIT_AFTER_SEND_DELAY state so its expiry ends the stop sequence instead of restarting the delay. Fixes: 2c1fd53af21b ("serial: amba-pl011: Fix RTS handling in RS485 mode") Cc: stable <stable@kernel.org> Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu <fanwu01@zju.edu.cn> Link: https://patch.msgid.link/20260731085915.326775-2-fanwu01@zju.edu.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03serial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xxRyan Wilbur
The NXP LPC32xx UART (PORT_LPC3220) can latch an RX character-timeout interrupt while the RX FIFO is empty: IIR reports UART_IIR_RX_TIMEOUT (0x0c) but LSR.DR is clear. A character timeout is only cleared by reading RHR, but serial8250_rx_chars() reads RHR only when LSR.DR is set, so nothing ever clears the condition. The interrupt is level-triggered and re-fires immediately, so on a single-core ARM926 the resulting interrupt storm livelocks the CPU. It is reproducible when userspace repeatedly opens the front-panel port (ttyS1): serial8250_do_set_termios() re-enables interrupts on unlock and the handler then spins forever with iir=0xcc lsr=0x60 ier=0x05, tripping the soft-lockup detector in serial8250_handle_irq_locked(). LPC32xx has no dedicated 8250 glue driver, it's driven by the generic 8250_of. Add a hardware specific handle_irq for PORT_LPC3220, wired up in of_platform_serial_setup() the same way fsl8250_handle_irq is installed. The handler follows dw8250_handle_irq(): on an RX timeout with an empty FIFO (LSR.DR and LSR.BI clear) it does one throwaway RHR read to clear the condition, then calls serial8250_handle_irq_locked(). No real received data is ever discarded, and it is a no-op on healthy UARTs which never report a timeout with DR clear. This is the same class of bug already worked around in other 8250 drivers; see commit 424d79183af0 ("serial: 8250_dw: Avoid "too much work" from bogus rx timeout interrupt") which reports the identical iir=0xcc/lsr=0x60. See also UART_RX_TIMEOUT_QUIRK in 8250_omap, and the note in 8250_bcm7271. Cc: stable <stable@kernel.org> Assisted-by: Claude:Opus4.8 Signed-off-by: Ryan Wilbur <rwilbur633@gmail.com> Link: https://patch.msgid.link/20260730193920.28954-1-rwilbur633@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: qcom-geni: Keep FIFO RX active during console TXBjorn Andersson
The GENI main sequencer handles console TX while the secondary sequencer handles FIFO RX. Before nbcon, the legacy console writer disabled both interrupt domains while it performed a long polled M-side transfer. This left the small S-side FIFO unserviced, allowing console input to overrun and be lost. The nbcon conversion replaces IRQ masking with the UART port lock, but a threaded console write still prevents the RX handler from draining the FIFO. Keep S-side RX enabled independently of M-side TX and drain it while refilling each bounded console command. This preserves interactive input during console output. Atomic output masks only M-side TX state, leaving FIFO RX handling independent. The threaded writer can also detect a SysRq character while it drains RX, so defer delivery until device_unlock() drops the UART port lock, as the existing IRQ path does with uart_unlock_and_check_sysrq(). Assisted-by: OpenCode:GPT-5.5 Signed-off-by: Bjorn Andersson <bjorn.andersson@oss.qualcomm.com> Link: https://patch.msgid.link/20260729-qcom-geni-nbcon-v1-2-3053b96465ed@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: qcom-geni: Convert console to nbconBjorn Andersson
The legacy GENI console writer serializes every message around a synchronous polled M-side transfer. It blocks printk callers for UART wire time and cannot provide atomic output while normal console output is active. Convert the console to nbcon threaded and atomic writers. Use the UART port lock as the device lock and bound threaded M-side commands so urgent diagnostics can take over atomic output. The threaded writer is batching the output in 32-source-byte commands, a value chosen to balance the command setup overhead with atomic-handoff latency. Atomic output can cancel an active normal TX command. Use irq_work to resume queued TTY output afterward, honor flow control, and prevent the deferred restart from accessing the port during shutdown or removal. Assisted-by: OpenCode:GPT-5.5 Signed-off-by: Bjorn Andersson <bjorn.andersson@oss.qualcomm.com> Link: https://patch.msgid.link/20260729-qcom-geni-nbcon-v1-1-3053b96465ed@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: qcom-geni: remove .pm callback, use runtime PM in startup/shutdownPraveen Talari
The driver currently relies on qcom_geni_serial_pm() through the uart_ops.pm callback to manage runtime PM references. However, the callback has a void return type, so failures from pm_runtime_resume_and_get() cannot be propagated to the caller. As a result, startup() may continue and access hardware even when the runtime PM resume operation failed, leading to register accesses while the device is not powered. Move runtime PM acquisition to qcom_geni_serial_startup() and release it to qcom_geni_serial_shutdown(). Since startup() can return an error, PM resume failures are now detected and propagated before any hardware initialization is performed. The startup/shutdown pair also provides a natural place to balance runtime PM references for normal port usage. During probe, uart_add_one_port() may configure the port before any user opens the TTY, meaning startup() has not yet been called. To keep the hardware powered during port registration, acquire a runtime PM reference with pm_runtime_resume_and_get() before uart_add_one_port() and release it with pm_runtime_put() afterwards. By moving runtime PM handling out of uart_ops.pm, resume failures are no longer silently ignored and all hardware accesses are guaranteed to occur while the device is powered. Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com> Link: https://patch.msgid.link/20260720-remove_uart_change_state-v2-1-30153ce4333b@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: 8250_exar: use platform_device_register_full()Bartosz Golaszewski
This driver doesn't really need to split the registration of the GPIO chip into stages, as platform_device_info already provides fields for the firmware node, parent device and the software node. Use platform_device_register_full() and simplify the code. This also addresses the problem with incorrect reference count of the assigned firmware node. Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com> Link: https://patch.msgid.link/20260728-exar-pdev-reg-full-v1-1-7a96e77309e1@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: sprd: Remove redundant dev_err()Pan Chuang
Since commit 55b48e23f5c4 ("genirq/devres: Add error handling in devm_request_*_irq()"), devm_request_irq() automatically logs detailed error messages on failure. Remove the now-redundant driver-specific dev_err() call. Signed-off-by: Pan Chuang <panchuang@vivo.com> Link: https://patch.msgid.link/20260722034342.316755-6-panchuang@vivo.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: mctrl_gpio: Remove redundant dev_err()Pan Chuang
Since commit 55b48e23f5c4 ("genirq/devres: Add error handling in devm_request_*_irq()"), devm_request_irq() automatically logs detailed error messages on failure. Remove the now-redundant driver-specific dev_err() call. Signed-off-by: Pan Chuang <panchuang@vivo.com> Link: https://patch.msgid.link/20260722034342.316755-5-panchuang@vivo.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: mvebu-uart: Remove redundant dev_err()Pan Chuang
Since commit 55b48e23f5c4 ("genirq/devres: Add error handling in devm_request_*_irq()"), devm_request_irq() automatically logs detailed error messages on failure. Remove the now-redundant driver-specific dev_err() calls. Signed-off-by: Pan Chuang <panchuang@vivo.com> Link: https://patch.msgid.link/20260722034342.316755-4-panchuang@vivo.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: imx: Remove redundant dev_err()Pan Chuang
Since commit 55b48e23f5c4 ("genirq/devres: Add error handling in devm_request_*_irq()"), devm_request_irq() automatically logs detailed error messages on failure. Remove the now-redundant driver-specific dev_err() calls. Signed-off-by: Pan Chuang <panchuang@vivo.com> Link: https://patch.msgid.link/20260722034342.316755-3-panchuang@vivo.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: 8250_bcm7271: Remove redundant dev_err_probe()Pan Chuang
Since commit 55b48e23f5c4 ("genirq/devres: Add error handling in devm_request_*_irq()"), devm_request_irq() automatically logs detailed error messages on failure. Remove the now-redundant driver-specific dev_err_probe() call. Signed-off-by: Pan Chuang <panchuang@vivo.com> Link: https://patch.msgid.link/20260722034342.316755-2-panchuang@vivo.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: bcm63xx-uart: silence false positive coccinelle warning on clk_putPei Xiao
Coccinelle warns about missing clk_put on the error path after clk_get, but the error path returns with an ERR_PTR where clk_put must not be called. Restructure into a single if block so the logic is clear to silence false positive coccinelle warning. Commit 580d952e44de ("tty: serial: bcm63xx: fix missing clk_put() in bcm63xx_uart") previously tried to fix this same warning by adding a clk_put, which was reverted because it was wrong. Prevent anyone from making the same mistake again. Signed-off-by: Pei Xiao <xiaopei01@kylinos.cn> Link: https://patch.msgid.link/604886147edb67c3ed85b192eb3f7a4a6dd0f0ac.1784788388.git.xiaopei01@kylinos.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: sh-sci: remove check for zero baud rate from uart_get_baud_rate()Hugo Villeneuve
The minimum baud rate supported by this driver is 0, so even for the B0 case, uart_get_baud_rate() will return 9600, not zero. This check is no longer necessary since commit 16ae2a877bf4 ("serial: Fix crash if the minimum rate of the device is > 9600 baud") so remove it. Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://patch.msgid.link/20260720193411.3517484-1-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: rsci: remove check for zero baud rate from uart_get_baud_rate()Hugo Villeneuve
The minimum baud rate supported by this driver is 0, so even for the B0 case, uart_get_baud_rate() will return 9600, not zero. This check is no longer necessary since commit 16ae2a877bf4 ("serial: Fix crash if the minimum rate of the device is > 9600 baud") so remove it. Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://patch.msgid.link/20260720195147.3630241-1-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30Revert "serial: 8250: drop lockdep annotation from serial8250_clear_IER()"John Ogness
This reverts commit 3d9e6f556e235ddcdc9f73600fdd46fe1736b090. The 8250 driver no longer depends on @oops_in_progress and will no longer violate the port->lock locking constraints. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Link: https://patch.msgid.link/20260729120439.281252-3-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: 8250: Switch to nbcon console, take 2John Ogness
Implement the necessary callbacks to switch the 8250 console driver to perform as an nbcon console. Add implementations for the nbcon console callbacks: ->write_atomic() ->write_thread() ->device_lock() ->device_unlock() and add CON_NBCON to the initial @flags. All hardware access in the callbacks is within unsafe sections. The ->write_atomic() and ->write_thread() callbacks allow safe handover/takeover per byte and add a preceding newline if they take over from another context mid-line. For the ->write_atomic() callback, a new irq_work is used to defer modem control since it may be called from a context that does not allow waking up tasks. During suspend/resume the irq_work is not used as this has been shown to cause suspend problems for some hardware. Upon resume, any pending modem control is performed. Note: A new __serial8250_clear_IER() is introduced for direct clearing of UART_IER during console writing (which will not be holding the port lock for atomic printing or KDB/KGDB). This allows restoring a lockdep check to serial8250_clear_IER() in a follow-up commit. Signed-off-by: John Ogness <john.ogness@linutronix.de> Link: https://patch.msgid.link/20260729120439.281252-2-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: 8250: remove always included kconfig.hHugo Villeneuve
The inclusion of <linux/kconfig.h> in commit 7ab80d1e72431 ("serial: 8250: fix compile error with hub6_match_port() when compiled as a module") is unneeded as it's guaranteed by the build starting from commit 2a11c8ea20bf ("kconfig: Introduce IS_ENABLED(), IS_BUILTIN() and IS_MODULE()"). Remove it here. Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patch.msgid.link/20260721144847.3728422-1-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: max310x: remove always included kconfig.hHugo Villeneuve
The inclusion of <linux/kconfig.h> in commit f18643843bc6 ("serial: max310x: fix compile errors if CONFIG_SPI_MASTER is disabled") is unneeded as it's guaranteed by the build starting from the commit 2a11c8ea20bf ("kconfig: Introduce IS_ENABLED(), IS_BUILTIN() and IS_MODULE()"). Remove it here. Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patch.msgid.link/20260721144420.3727708-1-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: qcom-geni: fix TX DMA buffer flushJan Sebastian Götte
When transmit flushing a qcom-geni UART during an ongoing TX DMA, the UART gets stuck infinitely repeating corrupted TX DMA frames. The DMA-mode uart_ops does not provide a flush_buffer callback, so an in-flight transfer can complete after serial core has reset the transmit kfifo, underflowing its length and resubmitting page-sized transfers indefinitely. Add one that stops the transfer and clears tx_remaining and tx_queued. The stop path was also broken: it unmapped the buffer while the serial engine could still read it, and never reset the TX DMA state machine. Cancel the main sequencer command first, then reset the state machine and wait for it before unmapping. Drop the early return so a pending mapping is also cleaned up when the main command is inactive. The bug can be triggered from userspace with a large write immediately followed by TCOFLUSH. A following tcdrain will hang forever. The bug was reproduced and this fix was validated on Arduino Uno Q (QRB2210) using /dev/ttyHS1. Assisted-by: Claude:claude-5-opus Codex:gpt-5 Signed-off-by: Jan Sebastian Götte <linux@jaseg.de> Fixes: 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") Cc: stable <stable@kernel.org> Reviewed-by: Praveen Talari <praveen.talari@oss.qualcomm.com> Link: https://patch.msgid.link/20260729174105.21838-2-git@jaseg.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: 8250_dma: Clear stale RX state on shutdownCunhao Lu
serial8250_release_dma() terminates RX DMA and releases the channel, but leaves rx_running set. If the port is closed while an RX transfer is active, the stale state remains while rxchan is NULL until the channel is requested again on the next open. The DesignWare BUSY workaround added by commit a7b9ce39fbe4 ("serial: 8250_dw: Ensure BUSY is deasserted") calls serial8250_rx_dma_flush() from the LCR write path during startup. This happens before serial8250_request_dma() obtains a new RX channel. On reopen, the stale rx_running state therefore makes the flush path pass a NULL channel to dmaengine_pause(), causing a kernel Oops. Clear rx_running after terminating RX DMA, matching the TX cleanup. Also make the flush helper return if the DMA object or RX channel is not available so startup and teardown paths cannot pass a NULL channel to the DMAengine API. Fixes: 0fcb7901f9d6 ("tty: serial: 8250_dma: keep own book keeping about RX transfers") Cc: stable <stable@kernel.org> Signed-off-by: Cunhao Lu <1579567540@qq.com> Link: https://patch.msgid.link/tencent_9EE2945F4C933B4D810C73C2D7485E000F06@qq.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30serial: sc16is7xx: enable THRI before filling TX FIFOLuca Fresi
sc16is7xx_handle_tx() currently requests the THRI enable only after it has filled the TX FIFO. The request is asynchronous because the IER update is performed later by reg_work. The SC16IS7xx generates a THRI interrupt when the TX FIFO crosses its trigger level. If the FIFO drains past that level before reg_work enables THRI, the chip does not generate a new interrupt. Characters remain queued indefinitely even though the hardware FIFO is empty. This was observed on an SC16IS752 while both UART channels were active. During the stall the software TX buffer remained non-empty while TXLVL reported 64 bytes free, LSR reported THR and transmitter empty, IER had THRI enabled, and IIR reported no interrupt pending. Enable THRI synchronously before filling the FIFO so the threshold crossing cannot be missed. Fixes: cc4c1d05eb10 ("sc16is7xx: Properly resume TX after stop") Cc: stable <stable@kernel.org> Signed-off-by: Luca Fresi <luca.fresi@bithiatec.com> Link: https://patch.msgid.link/20260721222404.204746-1-luca.fresi@bithiatec.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-30Revert "serial: 8250: Clear CON_PRINTBUFFER on port re-registration"Fushuai Wang
This reverts commit d338ab1d90603f875c4f7ed223406535378173a5. uart_console() only indicates that the port is selected as the console. It does not mean that the console has already been registered or has printed the buffered messages. On platforms where an initial 8250 port is replaced when the real UART device is registered, clearing CON_PRINTBUFFER causes the console to start at the end of the printk ring buffer. Without earlycon, all messages logged before UART registration are therefore lost. Fixes: d338ab1d9060 ("serial: 8250: Clear CON_PRINTBUFFER on port re-registration") Reported-by: Mark Brown <broonie@kernel.org> Reported-by: Anirudh Srinivasan <asrinivasan@oss.tenstorrent.com> Link: https://lore.kernel.org/all/20260522101042.21976-1-fushuai.wang@linux.dev/ Signed-off-by: Fushuai Wang <wangfushuai@baidu.com> Reviewed-by: John Ogness <john.ogness@linutronix.de> Link: https://patch.msgid.link/20260724093151.53216-1-fushuai.wang@linux.dev Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-27Merge 7.2-rc5 into tty-nextGreg Kroah-Hartman
We need the serial driver fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-17serial: sc16is7xx: implement gpio get_direction() callbackHugo Villeneuve
It's strongly recommended for GPIO drivers to always implement the .get_direction() callback - even when the direction is tracked in software. The GPIO core emits a warning when the callback is missing and a user reads the direction of a line, e.g. via /sys/kernel/debug/gpio. Fixes: dfeae619d781 ("serial: sc16is7xx") Cc: stable <stable@kernel.org> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com> Link: https://patch.msgid.link/20260716210813.2582826-1-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>