From 6b27426c469aa7fc79fa5a11cde33d61ddb53619 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:43:20 +0206 Subject: [PATCH 029/198] serial: 21285: 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 Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-4-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/21285.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/21285.c b/drivers/tty/serial/21285.c index d756fcc884cb..4de0c975ebdc 100644 --- a/drivers/tty/serial/21285.c +++ b/drivers/tty/serial/21285.c @@ -185,14 +185,14 @@ static void serial21285_break_ctl(struct uart_port *port, int break_state) unsigned long flags; unsigned int h_lcr; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); h_lcr = *CSR_H_UBRLCR; if (break_state) h_lcr |= H_UBRLCR_BREAK; else h_lcr &= ~H_UBRLCR_BREAK; *CSR_H_UBRLCR = h_lcr; - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static int serial21285_startup(struct uart_port *port) @@ -272,7 +272,7 @@ serial21285_set_termios(struct uart_port *port, struct ktermios *termios, if (port->fifosize) h_lcr |= H_UBRLCR_FIFO; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* * Update the per-port timeout. @@ -309,7 +309,7 @@ serial21285_set_termios(struct uart_port *port, struct ktermios *termios, *CSR_H_UBRLCR = h_lcr; *CSR_UARTCON = 1; - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static const char *serial21285_type(struct uart_port *port) -- 2.44.0