USB: serial: f81232: clear overrun flag

The F81232 will report data and LSR with bulk like following format:
bulk-in data: [LSR(1Byte)+DATA(1Byte)][LSR(1Byte)+DATA(1Byte)]...

LSR will auto clear frame/parity/break error flag when reading by H/W,
but overrrun will only cleared when reading LSR. So this patch add a
worker to read LSR when overrun and flush the worker on close() &
suspend().

Cc: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index dee6f2caf9b575260cf07944f562dfd4852adebe..840694bf57c17b4c718e9f3871db76a371dc5f16 100644 (file)
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -41,12 +41,14 @@ MODULE_DEVICE_TABLE(usb, id_table);
 #define FIFO_CONTROL_REGISTER          (0x02 + SERIAL_BASE_ADDRESS)
 #define LINE_CONTROL_REGISTER          (0x03 + SERIAL_BASE_ADDRESS)
 #define MODEM_CONTROL_REGISTER         (0x04 + SERIAL_BASE_ADDRESS)
+#define LINE_STATUS_REGISTER           (0x05 + SERIAL_BASE_ADDRESS)
 #define MODEM_STATUS_REGISTER          (0x06 + SERIAL_BASE_ADDRESS)
 
 struct f81232_private {
        struct mutex lock;
        u8 modem_control;
        u8 modem_status;
+       struct work_struct lsr_work;
        struct work_struct interrupt_work;
        struct usb_serial_port *port;
 };
@@ -282,6 +284,7 @@ exit:
 static void f81232_process_read_urb(struct urb *urb)
 {
        struct usb_serial_port *port = urb->context;
+       struct f81232_private *priv = usb_get_serial_port_data(port);
        unsigned char *data = urb->transfer_buffer;
        char tty_flag;
        unsigned int i;
@@ -315,6 +318,7 @@ static void f81232_process_read_urb(struct urb *urb)
 
                        if (lsr & UART_LSR_OE) {
                                port->icount.overrun++;
+                               schedule_work(&priv->lsr_work);
                                tty_insert_flip_char(&port->port, 0,
                                                TTY_OVERRUN);
                        }
@@ -562,6 +566,7 @@ static void f81232_close(struct usb_serial_port *port)
        usb_serial_generic_close(port);
        usb_kill_urb(port->interrupt_in_urb);
        flush_work(&port_priv->interrupt_work);
+       flush_work(&port_priv->lsr_work);
 }
 
 static void f81232_dtr_rts(struct usb_serial_port *port, int on)
@@ -606,6 +611,21 @@ static void  f81232_interrupt_work(struct work_struct *work)
        f81232_read_msr(priv->port);
 }
 
+static void f81232_lsr_worker(struct work_struct *work)
+{
+       struct f81232_private *priv;
+       struct usb_serial_port *port;
+       int status;
+       u8 tmp;
+
+       priv = container_of(work, struct f81232_private, lsr_work);
+       port = priv->port;
+
+       status = f81232_get_register(port, LINE_STATUS_REGISTER, &tmp);
+       if (status)
+               dev_warn(&port->dev, "read LSR failed: %d\n", status);
+}
+
 static int f81232_port_probe(struct usb_serial_port *port)
 {
        struct f81232_private *priv;
@@ -616,6 +636,7 @@ static int f81232_port_probe(struct usb_serial_port *port)
 
        mutex_init(&priv->lock);
        INIT_WORK(&priv->interrupt_work,  f81232_interrupt_work);
+       INIT_WORK(&priv->lsr_work, f81232_lsr_worker);
 
        usb_set_serial_port_data(port, priv);
 
@@ -646,8 +667,10 @@ static int f81232_suspend(struct usb_serial *serial, pm_message_t message)
 
        usb_kill_urb(port->interrupt_in_urb);
 
-       if (port_priv)
+       if (port_priv) {
                flush_work(&port_priv->interrupt_work);
+               flush_work(&port_priv->lsr_work);
+       }
 
        return 0;
 }