From f3a08238f90b3ada6988a984fa2fade2bf26f007 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:43:57 +0206 Subject: [PATCH 066/198] serial: mps2-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 Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-41-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/mps2-uart.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c index ea5a7911cb15..2a4c09f3a834 100644 --- a/drivers/tty/serial/mps2-uart.c +++ b/drivers/tty/serial/mps2-uart.c @@ -188,12 +188,12 @@ static irqreturn_t mps2_uart_rxirq(int irq, void *data) if (unlikely(!(irqflag & UARTn_INT_RX))) return IRQ_NONE; - spin_lock(&port->lock); + uart_port_lock(port); mps2_uart_write8(port, UARTn_INT_RX, UARTn_INT); mps2_uart_rx_chars(port); - spin_unlock(&port->lock); + uart_port_unlock(port); return IRQ_HANDLED; } @@ -206,12 +206,12 @@ static irqreturn_t mps2_uart_txirq(int irq, void *data) if (unlikely(!(irqflag & UARTn_INT_TX))) return IRQ_NONE; - spin_lock(&port->lock); + uart_port_lock(port); mps2_uart_write8(port, UARTn_INT_TX, UARTn_INT); mps2_uart_tx_chars(port); - spin_unlock(&port->lock); + uart_port_unlock(port); return IRQ_HANDLED; } @@ -222,7 +222,7 @@ static irqreturn_t mps2_uart_oerrirq(int irq, void *data) struct uart_port *port = data; u8 irqflag = mps2_uart_read8(port, UARTn_INT); - spin_lock(&port->lock); + uart_port_lock(port); if (irqflag & UARTn_INT_RX_OVERRUN) { struct tty_port *tport = &port->state->port; @@ -244,7 +244,7 @@ static irqreturn_t mps2_uart_oerrirq(int irq, void *data) handled = IRQ_HANDLED; } - spin_unlock(&port->lock); + uart_port_unlock(port); return handled; } @@ -356,12 +356,12 @@ mps2_uart_set_termios(struct uart_port *port, struct ktermios *termios, bauddiv = DIV_ROUND_CLOSEST(port->uartclk, baud); - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); uart_update_timeout(port, termios->c_cflag, baud); mps2_uart_write32(port, bauddiv, UARTn_BAUDDIV); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); -- 2.44.0