65 lines
2.6 KiB
Diff
65 lines
2.6 KiB
Diff
From 98036540f2e54a9bfa0bd4972c6f805d4a335f61 Mon Sep 17 00:00:00 2001
|
|
From: Thomas Gleixner <tglx@linutronix.de>
|
|
Date: Thu, 14 Sep 2023 20:44:29 +0206
|
|
Subject: [PATCH 098/196] serial: ucc_uart: Use port lock wrappers
|
|
|
|
When a serial port is used for kernel console output, then all
|
|
modifications to the UART registers which are done from other contexts,
|
|
e.g. getty, termios, are interference points for the kernel console.
|
|
|
|
So far this has been ignored and the printk output is based on the
|
|
principle of hope. The rework of the console infrastructure which aims to
|
|
support threaded and atomic consoles, requires to mark sections which
|
|
modify the UART registers as unsafe. This allows the atomic write function
|
|
to make informed decisions and eventually to restore operational state. It
|
|
also allows to prevent the regular UART code from modifying UART registers
|
|
while printk output is in progress.
|
|
|
|
All modifications of UART registers are guarded by the UART port lock,
|
|
which provides an obvious synchronization point with the console
|
|
infrastructure.
|
|
|
|
To avoid adding this functionality to all UART drivers, wrap the
|
|
spin_[un]lock*() invocations for uart_port::lock into helper functions
|
|
which just contain the spin_[un]lock*() invocations for now. In a
|
|
subsequent step these helpers will gain the console synchronization
|
|
mechanisms.
|
|
|
|
Converted with coccinelle. No functional change.
|
|
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
Acked-by: Timur Tabi <timur@kernel.org>
|
|
Signed-off-by: John Ogness <john.ogness@linutronix.de>
|
|
Link: https://lore.kernel.org/r/20230914183831.587273-73-john.ogness@linutronix.de
|
|
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
|
|
---
|
|
drivers/tty/serial/ucc_uart.c | 4 ++--
|
|
1 file changed, 2 insertions(+), 2 deletions(-)
|
|
|
|
diff --git a/drivers/tty/serial/ucc_uart.c b/drivers/tty/serial/ucc_uart.c
|
|
index b06661b80f41..ed7a6bb5596a 100644
|
|
--- a/drivers/tty/serial/ucc_uart.c
|
|
+++ b/drivers/tty/serial/ucc_uart.c
|
|
@@ -931,7 +931,7 @@ static void qe_uart_set_termios(struct uart_port *port,
|
|
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
|
|
|
|
/* Do we really need a spinlock here? */
|
|
- spin_lock_irqsave(&port->lock, flags);
|
|
+ uart_port_lock_irqsave(port, &flags);
|
|
|
|
/* Update the per-port timeout. */
|
|
uart_update_timeout(port, termios->c_cflag, baud);
|
|
@@ -949,7 +949,7 @@ static void qe_uart_set_termios(struct uart_port *port,
|
|
qe_setbrg(qe_port->us_info.tx_clock, baud, 16);
|
|
}
|
|
|
|
- spin_unlock_irqrestore(&port->lock, flags);
|
|
+ uart_port_unlock_irqrestore(port, flags);
|
|
}
|
|
|
|
/*
|
|
--
|
|
2.43.2
|
|
|