From b63e6f60eab45b16a1bf734fef9035a4c4187cd5 Mon Sep 17 00:00:00 2001 From: John Ogness Date: Tue, 7 Jan 2025 22:33:01 +0106 Subject: serial: 8250: Switch to nbcon console 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 register access in the callbacks are 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. Note: A new __serial8250_clear_IER() is introduced for direct clearing of UART_IER. This will allow to restore the lockdep check to serial8250_clear_IER() in a follow-up commit. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Tested-by: Petr Mladek Link: https://lore.kernel.org/r/20250107212702.169493-6-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_8250.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index 144de7a7948d..57875c37023a 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -150,8 +150,17 @@ struct uart_8250_port { #define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS u16 lsr_saved_flags; u16 lsr_save_mask; + + /* + * Track when a console line has been fully written to the + * hardware, i.e. true when the most recent byte written to + * UART_TX by the console was '\n'. + */ + bool console_line_ended; + #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA unsigned char msr_saved_flags; + struct irq_work modem_status_work; struct uart_8250_dma *dma; const struct uart_8250_ops *ops; @@ -202,8 +211,8 @@ void serial8250_tx_chars(struct uart_8250_port *up); unsigned int serial8250_modem_status(struct uart_8250_port *up); void serial8250_init_port(struct uart_8250_port *up); void serial8250_set_defaults(struct uart_8250_port *up); -void serial8250_console_write(struct uart_8250_port *up, const char *s, - unsigned int count); +void serial8250_console_write(struct uart_8250_port *up, + struct nbcon_write_context *wctxt, bool in_atomic); int serial8250_console_setup(struct uart_port *port, char *options, bool probe); int serial8250_console_exit(struct uart_port *port); -- cgit v1.2.3