return NULL;
}
+static void serial_8250_overrun_backoff_work(struct work_struct *work)
+{
+ struct uart_8250_port *up =
+ container_of(to_delayed_work(work), struct uart_8250_port,
+ overrun_backoff);
+ struct uart_port *port = &up->port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&port->lock, flags);
+ up->ier |= UART_IER_RLSI | UART_IER_RDI;
+ up->port.read_status_mask |= UART_LSR_DR;
+ serial_out(up, UART_IER, up->ier);
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
/**
* serial8250_register_8250_port - register a serial port
* @up: serial port template
ret = 0;
}
}
+
+ /* Initialise interrupt backoff work if required */
+ if (up->overrun_backoff_time_ms > 0) {
+ uart->overrun_backoff_time_ms = up->overrun_backoff_time_ms;
+ INIT_DELAYED_WORK(&uart->overrun_backoff,
+ serial_8250_overrun_backoff_work);
+ } else {
+ uart->overrun_backoff_time_ms = 0;
+ }
+
mutex_unlock(&serial_mutex);
return ret;
lsr = orig_lsr = up->port.serial_in(&up->port, UART_LSR);
- if (lsr & (UART_LSR_DR | UART_LSR_BI))
+ /* Process incoming characters first */
+ if ((lsr & (UART_LSR_DR | UART_LSR_BI)) &&
+ (up->ier & (UART_IER_RLSI | UART_IER_RDI))) {
lsr = serial8250_rx_chars(up, lsr);
+ }
+
+ /* Stop processing interrupts on input overrun */
+ if ((orig_lsr & UART_LSR_OE) && (up->overrun_backoff_time_ms > 0)) {
+ unsigned long delay;
+
+ up->ier = port->serial_in(port, UART_IER);
+ if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) {
+ port->ops->stop_rx(port);
+ } else {
+ /* Keep restarting the timer until
+ * the input overrun subsides.
+ */
+ cancel_delayed_work(&up->overrun_backoff);
+ }
+
+ delay = msecs_to_jiffies(up->overrun_backoff_time_ms);
+ schedule_delayed_work(&up->overrun_backoff, delay);
+ }
serial8250_modem_status(up);
if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
port8250.capabilities |= UART_CAP_AFE;
+ if (of_property_read_u32(ofdev->dev.of_node,
+ "overrun-throttle-ms",
+ &port8250.overrun_backoff_time_ms) != 0)
+ port8250.overrun_backoff_time_ms = 0;
+
ret = serial8250_register_8250_port(&port8250);
if (ret < 0)
goto err_dispose;
void (*dl_write)(struct uart_8250_port *, int);
struct uart_8250_em485 *em485;
+
+ /* Serial port overrun backoff */
+ struct delayed_work overrun_backoff;
+ u32 overrun_backoff_time_ms;
};
static inline struct uart_8250_port *up_to_u8250p(struct uart_port *up)