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From: Sven Eckelmann <sven@narfation.org>

Date: Mon, 15 Sep 2025 15:35:14 +0200

Subject: serial: ar933x: Handle break events

Signed-off-by: Sven Eckelmann <sven@narfation.org>

diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c

index acf891b50524760c5a648c8e119704182ec94de8..a6ca1355cdf051659079794f079706b7f8f6e33a 100644

--- a/drivers/tty/serial/ar933x_uart.c

+++ b/drivers/tty/serial/ar933x_uart.c

@@ -105,6 +105,30 @@ static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up)

ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);

}

+static inline void ar933x_uart_start_rxbreak_on_interrupt(struct ar933x_uart_port *up)

+{

+ up->ier |= AR933X_UART_INT_RX_BREAK_ON;

+ ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);

+}

+

+static inline void ar933x_uart_stop_rxbreak_on_interrupt(struct ar933x_uart_port *up)

+{

+ up->ier &= ~AR933X_UART_INT_RX_BREAK_ON;

+ ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);

+}

+

+static inline void ar933x_uart_start_rxbreak_off_interrupt(struct ar933x_uart_port *up)

+{

+ up->ier |= AR933X_UART_INT_RX_BREAK_OFF;

+ ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);

+}

+

+static inline void ar933x_uart_stop_rxbreak_off_interrupt(struct ar933x_uart_port *up)

+{

+ up->ier &= ~AR933X_UART_INT_RX_BREAK_OFF;

+ ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);

+}

+

static inline void ar933x_uart_start_rx_interrupt(struct ar933x_uart_port *up)

{

up->ier |= AR933X_UART_INT_RX_VALID;

@@ -212,6 +236,7 @@ static void ar933x_uart_stop_rx(struct uart_port *port)

container_of(port, struct ar933x_uart_port, port);

ar933x_uart_stop_rx_interrupt(up);

+ ar933x_uart_stop_rxbreak_on_interrupt(up);

}

static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)

@@ -448,11 +473,14 @@ static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)

{

struct ar933x_uart_port *up = dev_id;

unsigned int status;

+ bool is_break;

status = ar933x_uart_read(up, AR933X_UART_CS_REG);

if ((status & AR933X_UART_CS_HOST_INT) == 0)

return IRQ_NONE;

+ is_break = status & AR933X_UART_CS_RX_BREAK;

+

spin_lock(&up->port.lock);

status = ar933x_uart_read(up, AR933X_UART_INT_REG);

@@ -471,6 +499,29 @@ static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)

ar933x_uart_tx_chars(up);

}

+ if (status & AR933X_UART_INT_RX_BREAK_ON)

+ ar933x_uart_write(up, AR933X_UART_INT_REG,

+ AR933X_UART_INT_RX_BREAK_ON);

+

+ if (status & AR933X_UART_INT_RX_BREAK_OFF)

+ ar933x_uart_write(up, AR933X_UART_INT_REG,

+ AR933X_UART_INT_RX_BREAK_OFF);

+

+ if (is_break) {

+ /* disable "active break" interrupt */

+ ar933x_uart_stop_rxbreak_on_interrupt(up);

+ ar933x_uart_start_rxbreak_off_interrupt(up);

+

+ /* inform serial core about break */

+ up->port.icount.brk++;

+ if (!up->port.sysrq)

+ uart_handle_break(&up->port);

+ } else if (!(up->ier & AR933X_UART_INT_RX_BREAK_ON)) {

+ /* enable "active break" interrupt */

+ ar933x_uart_start_rxbreak_on_interrupt(up);

+ ar933x_uart_stop_rxbreak_off_interrupt(up);

+ }

+

spin_unlock(&up->port.lock);

return IRQ_HANDLED;

@@ -500,6 +551,7 @@ static int ar933x_uart_startup(struct uart_port *port)

/* Enable RX interrupts */

ar933x_uart_start_rx_interrupt(up);

+ ar933x_uart_start_rxbreak_on_interrupt(up);

spin_unlock_irqrestore(&up->port.lock, flags);

@@ -845,6 +897,7 @@ static int ar933x_uart_probe(struct platform_device *pdev)

port->fifosize = AR933X_UART_FIFO_SIZE;

port->ops = &ar933x_uart_ops;

port->rs485_config = ar933x_config_rs485;

+ port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_AR933X_CONSOLE);

baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);

up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);