kernel.git/drivers/tty/serial/8250, branch linux-6.7.y

serial: Lock console when calling into driver before registration

2024-04-03T13:11:17Z

[ Upstream commit 801410b26a0e8b8a16f7915b2b55c9528b69ca87 ] During the handoff from earlycon to the real console driver, we have two separate drivers operating on the same device concurrently. In the case of the 8250 driver these concurrent accesses cause problems due to the driver's use of banked registers, controlled by LCR.DLAB. It is possible for the setup(), config_port(), pm() and set_mctrl() callbacks to set DLAB, which can cause the earlycon code that intends to access TX to instead access DLL, leading to missed output and corruption on the serial line due to unintended modifications to the baud rate. In particular, for setup() we have: univ8250_console_setup() -> serial8250_console_setup() -> uart_set_options() -> serial8250_set_termios() -> serial8250_do_set_termios() -> serial8250_do_set_divisor() For config_port() we have: serial8250_config_port() -> autoconfig() For pm() we have: serial8250_pm() -> serial8250_do_pm() -> serial8250_set_sleep() For set_mctrl() we have (for some devices): serial8250_set_mctrl() -> omap8250_set_mctrl() -> __omap8250_set_mctrl() To avoid such problems, let's make it so that the console is locked during pre-registration calls to these callbacks, which will prevent the earlycon driver from running concurrently. Remove the partial solution to this problem in the 8250 driver that locked the console only during autoconfig_irq(), as this would result in a deadlock with the new approach. The console continues to be locked during autoconfig_irq() because it can only be called through uart_configure_port(). Although this patch introduces more locking than strictly necessary (and in particular it also locks during the call to rs485_config() which is not affected by this issue as far as I can tell), it follows the principle that it is the responsibility of the generic console code to manage the earlycon handoff by ensuring that earlycon and real console driver code cannot run concurrently, and not the individual drivers. Signed-off-by: Peter Collingbourne Reviewed-by: John Ogness Link: https://linux-review.googlesource.com/id/I7cf8124dcebf8618e6b2ee543fa5b25532de55d8 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240304214350.501253-1-pcc@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250_exar: Don't remove GPIO device on suspend

2024-03-26T22:18:52Z

[ Upstream commit 73b5a5c00be39e23b194bad10e1ea8bb73eee176 ] It seems a copy&paste mistake that suspend callback removes the GPIO device. There is no counterpart of this action, means once suspended there is no more GPIO device available untile full unbind-bind cycle is performed. Remove suspicious GPIO device removal in suspend. Fixes: d0aeaa83f0b0 ("serial: exar: split out the exar code from 8250_pci") Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20240219150627.2101198-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: serial: 8250: Set RS422 interface by default to fix Moxa RS422/RS485 PCIe boards

2024-02-05T20:17:04Z

[ Upstream commit 43f012df3c1e979966524f79b5371fde6545488a ] MOXA PCIe RS422/RS485 boards will not function by default because of the initial default serial interface of all MOXA PCIe boards is set to RS232. This patch fixes the problem above by setting the initial default serial interface to RS422 for those MOXA RS422/RS485 PCIe boards. Signed-off-by: Crescent CY Hsieh Reviewed-by: Jiri Slaby Link: https://lore.kernel.org/r/20231214060234.6147-1-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250: omap: Don't skip resource freeing if pm_runtime_resume_and_get() failed

2024-01-25T23:45:20Z

[ Upstream commit ad90d0358bd3b4554f243a425168fc7cebe7d04e ] Returning an error code from .remove() makes the driver core emit the little helpful error message: remove callback returned a non-zero value. This will be ignored. and then remove the device anyhow. So all resources that were not freed are leaked in this case. Skipping serial8250_unregister_port() has the potential to keep enough of the UART around to trigger a use-after-free. So replace the error return (and with it the little helpful error message) by a more useful error message and continue to cleanup. Fixes: e3f0c638f428 ("serial: 8250: omap: Fix unpaired pm_runtime_put_sync() in omap8250_remove()") Signed-off-by: Uwe Kleine-König Reviewed-by: Tony Lindgren Link: https://lore.kernel.org/r/20231110152927.70601-2-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250_exar: Set missing rs485_supported flag

2024-01-25T23:45:12Z

commit 0c2a5f471ce58bca8f8ab5fcb911aff91eaaa5eb upstream. The UART supports an auto-RTS mode in which the RTS pin is automatically activated during transmission. So mark this mode as being supported even if RTS is not controlled by the driver but the UART. Also the serial core expects now at least one of both modes rts-on-send or rts-after-send to be supported. This is since during sanitization unsupported flags are deleted from a RS485 configuration set by userspace. However if the configuration ends up with both flags unset, the core prints a warning since it considers such a configuration invalid (see uart_sanitize_serial_rs485()). Cc: Reviewed-by: Ilpo Järvinen Signed-off-by: Lino Sanfilippo Link: https://lore.kernel.org/r/20240103061818.564-8-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman

serial: 8250_bcm2835aux: Restore clock error handling

2024-01-25T23:45:12Z

commit 83e571f054cd742eb9a46d46ef05193904adf53f upstream. The commit fcc446c8aa63 ("serial: 8250_bcm2835aux: Add ACPI support") dropped the error handling for clock acquiring. But even an optional clock needs this. Fixes: fcc446c8aa63 ("serial: 8250_bcm2835aux: Add ACPI support") Cc: stable Signed-off-by: Stefan Wahren Reviewed-by: Florian Fainelli Link: https://lore.kernel.org/r/20231220114334.4712-1-wahrenst@gmx.net Signed-off-by: Greg Kroah-Hartman

serial: 8250_dw: Add ACPI ID for Granite Rapids-D UART

2023-12-07T01:48:56Z

Granite Rapids-D has an additional UART that is enumerated via ACPI. Add ACPI ID for it. Signed-off-by: Andy Shevchenko Cc: stable Link: https://lore.kernel.org/r/20231205195524.2705965-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: 8250: 8250_omap: Clear UART_HAS_RHR_IT_DIS bit

2023-11-23T20:21:10Z

This fixes commit 439c7183e5b9 ("serial: 8250: 8250_omap: Disable RX interrupt after DMA enable") which unfortunately set the UART_HAS_RHR_IT_DIS bit in the UART_OMAP_IER2 register and never cleared it. Cc: stable@vger.kernel.org Fixes: 439c7183e5b9 ("serial: 8250: 8250_omap: Disable RX interrupt after DMA enable") Signed-off-by: Ronald Wahl Reviewed-by: Vignesh Raghavendra Link: https://lore.kernel.org/r/20231031110909.11695-1-rwahl@gmx.de Signed-off-by: Greg Kroah-Hartman

serial: 8250_omap: Add earlycon support for the AM654 UART controller

2023-11-23T20:20:56Z

Currently there is no support for earlycon on the AM654 UART controller. This commit adds it. Signed-off-by: Ronald Wahl Reviewed-by: Vignesh Raghavendra Link: https://lore.kernel.org/r/20231031131242.15516-1-rwahl@gmx.de Cc: stable Signed-off-by: Greg Kroah-Hartman

serial: 8250: 8250_omap: Do not start RX DMA on THRI interrupt

2023-11-23T20:20:16Z

Starting RX DMA on THRI interrupt is too early because TX may not have finished yet. This change is inspired by commit 90b8596ac460 ("serial: 8250: Prevent starting up DMA Rx on THRI interrupt") and fixes DMA issues I had with an AM62 SoC that is using the 8250 OMAP variant. Cc: stable@vger.kernel.org Fixes: c26389f998a8 ("serial: 8250: 8250_omap: Add DMA support for UARTs on K3 SoCs") Signed-off-by: Ronald Wahl Reviewed-by: Vignesh Raghavendra Link: https://lore.kernel.org/r/20231101171431.16495-1-rwahl@gmx.de Signed-off-by: Greg Kroah-Hartman