On Mi, 2019-04-03 at 14:26 +0800, Ji-Ze Hong (Peter Hong) wrote:
> 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().
Hi,
I am most sorry to complain again. Please forgive me for being less
clear than necessary.
>
> Cc: Oliver Neukum <oneukum@xxxxxxxx>
> Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@xxxxxxxxx>
> ---
> v5:
> 1: Source code base revert to v3 and remove all v4 changes.
> 2: Add serial->suspending check in f81232_process_read_urb()
> before schedule_work(&priv->lsr_work) to avoid race condition.
>
> v4:
> 1: Add serial->suspending check in f81232_lsr_worker() to avoid
> re-trigger
> 2: Add port_priv-lsr_work_resched to re-trigger LSR worker
>
> v3:
> 1: Add flush_work(&port_priv->lsr_work) in f81232_suspend().
>
> v2:
> 1: Add flush_work(&port_priv->lsr_work) in f81232_close().
>
> drivers/usb/serial/f81232.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
> index 0dcdcb4b2cde..d8a0bb7a41f0 100644
> --- 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;
Here you need a flag
bool deferred_lsr_work_needed;
> + struct work_struct lsr_work;
> struct work_struct interrupt_work;
> struct usb_serial_port *port;
> };
> @@ -282,6 +284,8 @@ static void f81232_read_int_callback(struct urb *urb)
> static void f81232_process_read_urb(struct urb *urb)
> {
> struct usb_serial_port *port = urb->context;
> + struct usb_serial *serial = port->serial;
> + struct f81232_private *priv = usb_get_serial_port_data(port);
> unsigned char *data = urb->transfer_buffer;
> char tty_flag;
> unsigned int i;
> @@ -315,6 +319,9 @@ static void f81232_process_read_urb(struct urb *urb)
>
> if (lsr & UART_LSR_OE) {
> port->icount.overrun++;
> +
> + if (!serial->suspending)
> + schedule_work(&priv->lsr_work);
Yes, but you cannot just drop it. You also need
else
priv->deferred_lsr_work_needed = true;
> tty_insert_flip_char(&port->port, 0,
> TTY_OVERRUN);
> }
> @@ -556,9 +563,12 @@ static int f81232_open(struct tty_struct *tty, struct usb_serial_port *port)
>
> static void f81232_close(struct usb_serial_port *port)
> {
> + struct f81232_private *port_priv = usb_get_serial_port_data(port);
> +
> f81232_port_disable(port);
> usb_serial_generic_close(port);
> usb_kill_urb(port->interrupt_in_urb);
> + flush_work(&port_priv->lsr_work);
> }
>
> static void f81232_dtr_rts(struct usb_serial_port *port, int on)
> @@ -603,6 +613,21 @@ 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;
> @@ -613,6 +638,7 @@ 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);
>
> @@ -632,6 +658,16 @@ static int f81232_port_remove(struct usb_serial_port *port)
> return 0;
> }
>
> +static int f81232_suspend(struct usb_serial *serial, pm_message_t message)
> +{
> + struct f81232_private *port_priv;
> +
> + port_priv = usb_get_serial_port_data(serial->port[0]);
> + flush_work(&port_priv->lsr_work);
> +
> + return 0;
> +}
And you do need a resume, which you had in version v4 to check
the deferred_lsr_work_needed flag and schedule the work if it is
set.
Most sorry
Oliver
