kernel/linux.git/drivers/tty, branch v5.10.259

tty: serial: samsung: Remove redundant port lock acquisition in rx helpers

2026-06-19T11:21:48+00:00

[ Upstream commit a3bb136bff5e6a5e48cdd813246c9c4686feaaa9 ] Sashiko identified a deadlock when the console flow is engaged [1]. When console flow control is enabled (UPF_CONS_FLOW), s3c24xx_serial_stop_tx() calls s3c24xx_serial_rx_enable() and s3c24xx_serial_start_tx() calls s3c24xx_serial_rx_disable(). The serial core framework invokes the .stop_tx() and .start_tx() callbacks with the port->lock spinlock already held. Furthermore, all internal driver paths that invoke stop_tx (such as the DMA TX completion handler s3c24xx_serial_tx_dma_complete() or the PIO TX IRQ handler s3c24xx_serial_tx_irq()) also acquire port->lock prior to calling it. (Note that s3c24xx_serial_start_tx() is only invoked by the serial core). However, s3c24xx_serial_rx_enable() and s3c24xx_serial_rx_disable() unconditionally attempt to acquire port->lock again using uart_port_lock_irqsave(). Since spinlocks are not recursive, this causes a deadlock on the same CPU when console flow control is engaged. Remove the redundant lock acquisition from both rx helper functions. Cc: stable Fixes: b497549a035c ("[ARM] S3C24XX: Split serial driver into core and per-cpu drivers") Reported-by: John Ogness Closes: https://sashiko.dev/#/patchset/20260506121606.5805-1-john.ogness%40linutronix.de [1] Signed-off-by: Tudor Ambarus Link: https://patch.msgid.link/20260515-samsung-tty-flow-control-deadlock-v1-1-93255edbc9bc@linaro.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: use u32 for register interactions

2026-06-19T11:21:48+00:00

[ Upstream commit 032a725c16add79332d774348d7ad7d0d4b86479 ] All registers of the IP have 32 bits. Use u32 variables when reading or writing from/to the registers. The purpose of those variables becomes clearer. Reviewed-by: Sam Protsenko Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20240119104526.1221243-9-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman Stable-dep-of: a3bb136bff5e ("tty: serial: samsung: Remove redundant port lock acquisition in rx helpers") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

serial: samsung_tty: Use port lock wrappers

2026-06-19T11:21:48+00:00

[ Upstream commit 97d7a9aeba1d424c2359f1686d02c75d798ad184 ] When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-54-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Stable-dep-of: a3bb136bff5e ("tty: serial: samsung: Remove redundant port lock acquisition in rx helpers") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

serial: altera_jtaguart: handle uart_add_one_port() failures

2026-06-19T11:21:46+00:00

[ Upstream commit ea66be25f0e934f49d24cd0c5845d13cdba3520b ] altera_jtaguart_probe() maps the register window before registering the UART port, but it ignores failures from uart_add_one_port(). If port registration fails, probe still returns success and the mapping remains live until a later remove path that is not part of probe failure cleanup. Return the uart_add_one_port() error and unmap the register window on that failure path. This issue was identified during our ongoing static-analysis research while reviewing kernel code. Fixes: 5bcd601049c6 ("serial: Add driver for the Altera JTAG UART") Cc: stable Co-developed-by: Ijae Kim Signed-off-by: Ijae Kim Signed-off-by: Myeonghun Pak Link: https://patch.msgid.link/20260512065837.79528-1-mhun512@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

serial: altera_jtaguart: Use platform_get_irq_optional() to get the interrupt

2026-06-19T11:21:46+00:00

[ Upstream commit 60302276caff50f907bc3391a364691ab4a21b43 ] platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static allocation of IRQ resources in DT core code, this causes an issue when using hierarchical interrupt domains using "interrupts" property in the node as this bypasses the hierarchical setup and messes up the irq chaining. In preparation for removal of static setup of IRQ resource from DT core code use platform_get_irq_optional(). Signed-off-by: Lad Prabhakar Link: https://lore.kernel.org/r/20211224142917.6966-7-prabhakar.mahadev-lad.rj@bp.renesas.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: ea66be25f0e9 ("serial: altera_jtaguart: handle uart_add_one_port() failures") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

serial: qcom-geni: fix UART_RX_PAR_EN bit position

2026-06-19T11:21:46+00:00

[ Upstream commit ca2584d841b69391ffc4144840563d2e1a0018df ] UART_RX_PAR_EN is incorrectly defined as bit 3, which triggers false framing errors (S_GP_IRQ_1_EN) and causes received data to be dropped when parity is enabled and the parity bit is 0. Define UART_RX_PAR_EN as bit 4 of the SE_UART_RX_TRANS_CFG register, as specified in the reference manual. Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Cc: stable Signed-off-by: Prasanna S Reviewed-by: Konrad Dybcio Link: https://patch.msgid.link/20260428-serial-bit-correct-v1-1-9131ad5b97d8@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

tty: serial: qcom-geni-serial: align #define values

2026-06-19T11:21:46+00:00

[ Upstream commit 6cde11dbf4b65170eeefba48df730c93d75e01a3 ] Keep the #define symbols aligned for better readability. Signed-off-by: Bartosz Golaszewski Reviewed-by: Konrad Dybcio Link: https://lore.kernel.org/r/20221229155030.418800-5-brgl@bgdev.pl Signed-off-by: Greg Kroah-Hartman Stable-dep-of: ca2584d841b6 ("serial: qcom-geni: fix UART_RX_PAR_EN bit position") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

tty: serial: qcom-geni-serial: remove unused symbols

2026-06-19T11:21:46+00:00

[ Upstream commit 68c6bd92c86cbc4937834c79963b27c77ee3bf51 ] Drop all unused symbols from the driver. Signed-off-by: Bartosz Golaszewski Reviewed-by: Konrad Dybcio Link: https://lore.kernel.org/r/20221229155030.418800-4-brgl@bgdev.pl Signed-off-by: Greg Kroah-Hartman Stable-dep-of: ca2584d841b6 ("serial: qcom-geni: fix UART_RX_PAR_EN bit position") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

serial: dz: Fix bootconsole handover lockup

2026-06-19T11:21:32+00:00

commit 7f127b2208e5e2b817243cad41fe4211a6d5a7a3 upstream. Calling dz_reset() in the course of setting up the serial device causes line parameters to be reset and the transmitter disabled. We've been lucky in that no message is usually produced to the kernel log between this call and the later call to uart_set_options() in the course of console setup done by dz_serial_console_init(), or the system would hang as the console output handler in the firmware tried to access a port the transmitter of which has been disabled and line parameters messed up. This will change with the next change to the driver, so fix dz_reset() such that line parameters are set for 9600n8 console operation as with the system firmware and the transmitter re-enabled after reset. This also means dz_pm() serves no purpose anymore, so drop it. Fixes: e6ee512f5a77 ("dz.c: Resource management") Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v2.6.25+ Link: https://patch.msgid.link/alpine.DEB.2.21.2605062302010.46195@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman [ Avoid C99+ 'for' loop initial declaration for 5.10.y. ] Signed-off-by: Maciej W. Rozycki Signed-off-by: Sasha Levin

serial: zs: Switch to using channel reset

2026-06-19T11:21:32+00:00

commit 8572955630f30948837088aa98bcbe0532d1ceac upstream. Switch the driver to using the channel reset rather than hardware reset, simplifying handling by removing an interference between channels that causes the other channel to become uninitialised afterwards. There is little difference between the two kinds of reset in terms of register settings that result, and we initialise the whole register set right away anyway. However this prevents a hang from happening should the console output handler in the firmware try to access the other port whose transmitter has been disabled and line parameters messed up. For example this will happen if the keyboard port (port A) is chosen for the system console, unusually but not insanely for a headless system, as the port is wired to a standard DA-15 connector and an adapter can be easily made. Or with the next change in place this would happen for the regular console port (port B), since the keyboard port (port A) will be initialised first. Just remove the unnecessary complication then, a channel reset is good enough. We still need the initialisation marker, now per channel rather than per SCC, as for the console port zs_reset() will be called twice: once early on via zs_serial_console_init() for the console setup only, and then again via zs_config_port() as the port is associated with a TTY device. Fixes: 8b4a40809e53 ("zs: move to the serial subsystem") Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v2.6.23+ Link: https://patch.msgid.link/alpine.DEB.2.21.2605062323430.46195@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman