This is v5 of a series to convert the 8250 driver to an NBCON console, providing both threaded and atomic printing implementations. v4 of this series is here [0]. Additional background information about NBCON consoles in general is available in the cover letter of v2 [1]. The changes since v4: - In wait_for_lsr() use else-condition for fallback timeout. - In fifo_wait_for_lsr() remove unnecessary return value. - In serial8250_console_fifo_write() enter/exit unsafe section for each character to avoid writing to UART_TX on handover/takeover. - In serial8250_console_byte_write() enter/exit unsafe section for each character rather than calling nbcon_can_proceed() for each character because nbcon_can_proceed() only checks ownership but does not actually handover if within an unsafe section. If there is a higher priority waiter, we want to handover ASAP so that printing can continue in the higher priority context. - In serial8250_console_write() cleanup the implementation so that the procedure is more obvious. - Add detailed multi-line comment documenting uart_8250_port->console_line_ended. - Add and extend comments as requested. John Ogness [0] https://lore.kernel.org/lkml/20241227224523.28131-1-john.ogness@xxxxxxxxxxxxx [1] https://lore.kernel.org/lkml/20240913140538.221708-1-john.ogness@xxxxxxxxxxxxx John Ogness (6): serial: 8250: Adjust the timeout for FIFO mode serial: 8250: Use frame time to determine timeout serial: 8250: Use high-level writing function for FIFO serial: 8250: Provide flag for IER toggling for RS485 serial: 8250: Switch to nbcon console serial: 8250: Revert "drop lockdep annotation from serial8250_clear_IER()" drivers/tty/serial/8250/8250.h | 4 +- drivers/tty/serial/8250/8250_bcm2835aux.c | 4 +- drivers/tty/serial/8250/8250_core.c | 35 ++- drivers/tty/serial/8250/8250_omap.c | 2 +- drivers/tty/serial/8250/8250_port.c | 259 +++++++++++++++++----- include/linux/serial_8250.h | 17 +- 6 files changed, 254 insertions(+), 67 deletions(-) base-commit: 2c1fd53af21b8cb13878b054894d33d3383eb1f3 -- 2.39.5
