kernel.git/drivers/tty/serial/uartlite.c, branch linux-6.1.y

serial: Make uart_remove_one_port() return void

2026-01-11T14:19:23Z

[ Upstream commit d5b3d02d0b107345f2a6ecb5b06f98356f5c97ab ] The return value is only ever used as a return value for remove callbacks of platform drivers. This return value is ignored by the driver core. (The only effect is an error message, but uart_remove_one_port() already emitted one in this case.) So the return value isn't used at all and uart_remove_one_port() can be changed to return void without any loss. Also this better matches the Linux device model as remove functions are not supposed to fail. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20230512173810.131447-3-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 74098cc06e75 ("xhci: dbgtty: fix device unregister: fixup") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

tty: serial: uartlite: register uart driver in init

2025-07-06T08:57:55Z

[ Upstream commit 6bd697b5fc39fd24e2aa418c7b7d14469f550a93 ] When two instances of uart devices are probing, a concurrency race can occur. If one thread calls uart_register_driver function, which first allocates and assigns memory to 'uart_state' member of uart_driver structure, the other instance can bypass uart driver registration and call ulite_assign. This calls uart_add_one_port, which expects the uart driver to be fully initialized. This leads to a kernel panic due to a null pointer dereference: [ 8.143581] BUG: kernel NULL pointer dereference, address: 00000000000002b8 [ 8.156982] #PF: supervisor write access in kernel mode [ 8.156984] #PF: error_code(0x0002) - not-present page [ 8.156986] PGD 0 P4D 0 ... [ 8.180668] RIP: 0010:mutex_lock+0x19/0x30 [ 8.188624] Call Trace: [ 8.188629] ? __die_body.cold+0x1a/0x1f [ 8.195260] ? page_fault_oops+0x15c/0x290 [ 8.209183] ? __irq_resolve_mapping+0x47/0x80 [ 8.209187] ? exc_page_fault+0x64/0x140 [ 8.209190] ? asm_exc_page_fault+0x22/0x30 [ 8.209196] ? mutex_lock+0x19/0x30 [ 8.223116] uart_add_one_port+0x60/0x440 [ 8.223122] ? proc_tty_register_driver+0x43/0x50 [ 8.223126] ? tty_register_driver+0x1ca/0x1e0 [ 8.246250] ulite_probe+0x357/0x4b0 [uartlite] To prevent it, move uart driver registration in to init function. This will ensure that uart_driver is always registered when probe function is called. Signed-off-by: Jakub Lewalski Signed-off-by: Elodie Decerle Link: https://lore.kernel.org/r/20250331160732.2042-1-elodie.decerle@nokia.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: Make ->set_termios() old ktermios const

2022-08-30T12:22:35Z

There should be no reason to adjust old ktermios which is going to get discarded anyway. Reviewed-by: Andy Shevchenko Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220816115739.10928-7-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: uartlite: Fix BRKINT clearing

2022-05-19T16:32:39Z

BRKINT is within c_iflag rather than c_cflag. Fixes: ea017f5853e9 (tty: serial: uartlite: Prevent changing fixed parameters) Reviewed-by: Sean Anderson Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220519081808.3776-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: make uart_console_write->putchar()'s character an unsigned char

2022-03-03T14:06:31Z

Currently, uart_console_write->putchar's second parameter (the character) is of type int. It makes little sense, provided uart_console_write() accepts the input string as "const char *s" and passes its content -- the characters -- to putchar(). So switch the character's type to unsigned char. We don't use char as that is signed on some platforms. That would cause troubles for drivers which (implicitly) cast the char to u16 when writing to the device. Sign extension would happen in that case and the value written would be completely different to the provided char. DZ is an example of such a driver -- on MIPS, it uses u16 for dz_out in dz_console_putchar(). Note we do the char -> uchar conversion implicitly in uart_console_write(). Provided we do not change size of the data type, sign extension does not happen there, so the problem is void. This makes the types consistent and unified with the rest of the uart layer, which uses unsigned char in most places already. One exception is xmit_buf, but that is going to be converted later. Cc: Paul Cercueil Cc: Tobias Klauser Cc: Russell King Cc: Vineet Gupta Cc: Nicolas Ferre Cc: Alexandre Belloni Cc: Ludovic Desroches Cc: Florian Fainelli Cc: bcm-kernel-feedback-list@broadcom.com Cc: Alexander Shiyan Cc: Baruch Siach Cc: "Maciej W. Rozycki" Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Shawn Guo Cc: Sascha Hauer Cc: Pengutronix Kernel Team Cc: Fabio Estevam Cc: NXP Linux Team Cc: Karol Gugala Cc: Mateusz Holenko Cc: Vladimir Zapolskiy Cc: Neil Armstrong Cc: Kevin Hilman Cc: Jerome Brunet Cc: Martin Blumenstingl Cc: Taichi Sugaya Cc: Takao Orito Cc: Liviu Dudau Cc: Sudeep Holla Cc: Lorenzo Pieralisi Cc: "Andreas Färber" Cc: Manivannan Sadhasivam Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Andy Gross Cc: Bjorn Andersson Cc: Krzysztof Kozlowski Cc: Orson Zhai Cc: Baolin Wang Cc: Chunyan Zhang Cc: Patrice Chotard Cc: Maxime Coquelin Cc: Alexandre Torgue Cc: "David S. Miller" Cc: Peter Korsgaard Cc: Michal Simek Acked-by: Richard Genoud [atmel_serial] Acked-by: Uwe Kleine-König Acked-by: Paul Cercueil Acked-by: Neil Armstrong # meson_serial Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20220303080831.21783-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: serial: uartlite: allow 64 bit address

2021-12-03T13:12:56Z

The base address of uartlite registers could be 64 bit address which is from device resource. When ulite_probe() calls ulite_assign(), this 64 bit address is casted to 32-bit. The fix is to replace "u32" type with "phys_addr_t" type for the base address in ulite_assign() argument list. Fixes: 8fa7b6100693 ("[POWERPC] Uartlite: Separate the bus binding from the driver proper") Signed-off-by: Lizhi Hou Link: https://lore.kernel.org/r/20211129202302.1319033-1-lizhi.hou@xilinx.com Signed-off-by: Greg Kroah-Hartman

tty: serial: uartlite: Prevent changing fixed parameters

2021-09-14T08:05:32Z

This device does not support changing baud, parity, data bits, stop bits, or detecting breaks. Disable "changing" these settings to prevent their termios from diverging from the actual state of the uart. In order to determine the correct parameters to enforce, we read the various new devicetree parameters to discover how the uart was configured when it was synthesized. The defaults match ulite_console_setup. xlnx,use-parity, xlnx,odd-parity, and xlnx,data-bits are optional since there were in-tree users (and presumably out-of-tree users) who did not set them. Signed-off-by: Sean Anderson Link: https://lore.kernel.org/r/20210826192154.3202269-5-sean.anderson@seco.com Signed-off-by: Greg Kroah-Hartman

tty: serial: uartlite: Use read_poll_timeout for a polling loop

2021-08-27T14:34:32Z

read_poll_timeout was recently introduced, and can be used to simplify our console polling loop. This results in a slight reduction in code. early_uartlite_putc can't get the same treatment, because it can be called before udelay is set up. Signed-off-by: Sean Anderson Link: https://lore.kernel.org/r/20210826192549.3203071-1-sean.anderson@seco.com Signed-off-by: Greg Kroah-Hartman

tty: serial: uartlite: Use constants in early_uartlite_putc

2021-08-27T14:34:04Z

Use the constants defined at the beginning of this file instead of integer literals when accessing registers. This makes this code easier to read, and obviates the need for some explanatory comments. Signed-off-by: Sean Anderson Link: https://lore.kernel.org/r/20210826194323.3209227-1-sean.anderson@seco.com Signed-off-by: Greg Kroah-Hartman

tty: serial: uartlite: Add runtime pm support

2021-07-21T10:46:52Z

In the commit 07e5d4ff125a ("Revert serial-uartlite: Add runtime support") the runtime pm support was reverted to aid reverting of the other patches. This patch adds the runtime PM support back. The runtime pm calls are used to gate and enable the clocks. Signed-off-by: Shubhrajyoti Datta Link: https://lore.kernel.org/r/20210713064835.27978-3-shubhrajyoti.datta@xilinx.com Signed-off-by: Greg Kroah-Hartman