From 910ef438e93cd2ceb70c72caea418710d648feef Mon Sep 17 00:00:00 2001 From: John Ogness Date: Tue, 7 Jan 2025 22:33:00 +0106 Subject: serial: 8250: Provide flag for IER toggling for RS485 For RS485 mode, if SER_RS485_RX_DURING_TX is not available, the console ->write() callback needs to enable/disable Tx. It does this by calling the ->rs485_start_tx() and ->rs485_stop_tx() callbacks. However, some of these callbacks also disable/enable interrupts and makes power management calls. This causes 2 problems for console writing: 1. A console write can occur in contexts that are illegal for pm_runtime_*(). It is not even necessary for console writing to use pm_runtime_*() because a console already does this in serial8250_console_setup() and serial8250_console_exit(). 2. The console ->write() callback already handles disabling/enabling the interrupts by properly restoring the previous IER value. Add an argument @toggle_ier to the ->rs485_start_tx() and ->rs485_stop_tx() callbacks to specify if they may disable/enable receive interrupts while using pm_runtime_*(). Console writing will not allow the toggling. For all call sites other than console writing there is no functional change. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20250107212702.169493-5-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_8250.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index e0717c8393d7..144de7a7948d 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -161,8 +161,8 @@ struct uart_8250_port { void (*dl_write)(struct uart_8250_port *up, u32 value); struct uart_8250_em485 *em485; - void (*rs485_start_tx)(struct uart_8250_port *); - void (*rs485_stop_tx)(struct uart_8250_port *); + void (*rs485_start_tx)(struct uart_8250_port *up, bool toggle_ier); + void (*rs485_stop_tx)(struct uart_8250_port *up, bool toggle_ier); /* Serial port overrun backoff */ struct delayed_work overrun_backoff; -- cgit v1.2.3