Re: [PATCH V8 1/4] USB: serial: f81232: clear overrun flag

Johan Hovold
2019-04-26T06:23:18Z

On Fri, Apr 19, 2019 at 10:45:30AM +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().
>
> Cc: Oliver Neukum <oneukum@suse.com>
> Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
> ---
> v8:
> 1: Fix usb_submit_urb() in f81232_resume() with GFP_NOIO, not
> GFP_KERNEL.
>
> v7:
> 1: Remove serial->suspending check
> 2: Add port priv is_port_open to save port open state. We'll
> register interrupt-in urb in f81232_resume() when port is
> opened.
> 3: Using usb_kill_urb for read/interrupt urb to ensure urb
> stopped.

> drivers/usb/serial/f81232.c | 97 +++++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 89 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
> index 0dcdcb4b2cde..1f0dd4087d79 100644
> --- a/drivers/usb/serial/f81232.c
> +++ b/drivers/usb/serial/f81232.c
> @@ -41,12 +41,15 @@ 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;
> + bool is_port_open;

This patch can be simplified by using the tty_port_initialized() macro
in resume instead of adding a new open flag. This is the common way USB
serial drivers deal with this and will allow a lot the new locking to go
away.

> +static int f81232_resume(struct usb_serial *serial)
> +{
> + struct usb_serial_port *port = serial->port[0];
> + struct f81232_private *port_priv = usb_get_serial_port_data(port);
> + int result = 0;
> +
> + mutex_lock(&port_priv->lock);
> +
> + if (port_priv && port_priv->is_port_open) {
> + result = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
> + if (result) {
> + dev_err(&port->dev,
> + "%s: submit interrupt urb failed: %d",
> + __func__, result);

Missing '\n', also please drop the function prefix.

Johan