diff options
| -rw-r--r-- | drivers/tty/serial/8250/8250_core.c | 25 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250_fsl.c | 23 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250_of.c | 5 | ||||
| -rw-r--r-- | include/linux/serial_8250.h | 4 |
4 files changed, 56 insertions, 1 deletions
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 94f3e1c64490..189ab1212d9a 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -942,6 +942,21 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port * 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 @@ -1056,6 +1071,16 @@ int serial8250_register_8250_port(struct uart_8250_port *up) 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; diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c index ff3dcaea5d93..aa0e216d5ead 100644 --- a/drivers/tty/serial/8250/8250_fsl.c +++ b/drivers/tty/serial/8250/8250_fsl.c @@ -49,8 +49,29 @@ int fsl8250_handle_irq(struct uart_port *port) 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); diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c index 877fd7f8a8ed..a1a85805d010 100644 --- a/drivers/tty/serial/8250/8250_of.c +++ b/drivers/tty/serial/8250/8250_of.c @@ -240,6 +240,11 @@ static int of_platform_serial_probe(struct platform_device *ofdev) 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; diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index 18e21427bce4..5a655ba8d273 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -134,6 +134,10 @@ struct uart_8250_port { 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) |