linux-kernel - Re: [PATCH v4 4/7] usb: serial: reimplement RX bulk-in ep for F81232

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Date:	Wed, 4 Feb 2015 13:51:04 +0100
From:	Johan Hovold <johan@...nel.org>
To:	Peter Hung <hpeter@...il.com>
Cc:	johan@...nel.org, gregkh@...uxfoundation.org,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	tom_tsai@...tek.com.tw, peter_hong@...tek.com.tw,
	Peter Hung <hpeter+linux_kernel@...il.com>
Subject: Re: [PATCH v4 4/7] usb: serial: reimplement RX bulk-in ep for F81232

On Fri, Jan 30, 2015 at 02:13:38PM +0800, Peter Hung wrote:
> The F81232 bulk-in is RX data channel. Data format is
> [LSR+Data][LSR+Data]..... , We had reimplemented in this patch.
> 
> Signed-off-by: Peter Hung <hpeter+linux_kernel@...il.com>
> ---
>  drivers/usb/serial/f81232.c | 47 +++++++++++++++------------------------------
>  1 file changed, 15 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
> index 274120d..12e1ae4 100644
> --- a/drivers/usb/serial/f81232.c
> +++ b/drivers/usb/serial/f81232.c
> @@ -194,47 +194,30 @@ 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 = TTY_NORMAL;
> -	unsigned long flags;
> -	u8 line_status;
> +	u8 line_status = 0;
>  	int i;
>  
> -	/* update line status */
> -	spin_lock_irqsave(&priv->lock, flags);
> -	line_status = priv->line_status;
> -	priv->line_status &= ~UART_STATE_TRANSIENT_MASK;
> -	spin_unlock_irqrestore(&priv->lock, flags);
> -
>  	if (!urb->actual_length)
>  		return;
>  
> -	/* break takes precedence over parity, */
> -	/* which takes precedence over framing errors */
> -	if (line_status & UART_BREAK_ERROR)
> -		tty_flag = TTY_BREAK;
> -	else if (line_status & UART_PARITY_ERROR)
> -		tty_flag = TTY_PARITY;
> -	else if (line_status & UART_FRAME_ERROR)
> -		tty_flag = TTY_FRAME;
> -	dev_dbg(&port->dev, "%s - tty_flag = %d\n", __func__, tty_flag);
> -
> -	/* overrun is special, not associated with a char */
> -	if (line_status & UART_OVERRUN_ERROR)
> -		tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
> -
> -	if (port->port.console && port->sysrq) {
> -		for (i = 0; i < urb->actual_length; ++i)
> -			if (!usb_serial_handle_sysrq_char(port, data[i]))
> -				tty_insert_flip_char(&port->port, data[i],
> -						tty_flag);
> -	} else {
> -		tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
> -							urb->actual_length);
> +	/* bulk-in data: [LSR(1Byte)+DATA(1Byte)][LSR(1Byte)+DATA(1Byte)]... */
> +
> +	if (urb->actual_length >= 2) {

Just return unless length < 2 and reduce indentation below.

Should should probably make sure the returned length is even as well.

> +
> +		for (i = 0 ; i < urb->actual_length ; i += 2) {
> +			line_status |= data[i+0];
> +			tty_insert_flip_string_fixed_flag(&port->port,
> +				&data[i+1], tty_flag, 1);
> +		}
> +
> +		if (unlikely(line_status & UART_LSR_OE))
> +			tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);

This needs some more work as you need to determine tty_flag for each
character based on the line status using the priorities that you remove
above (i.e. break takes precedence over parity, etc).

Also insert a overrun char for every individual overrun error.

> +
> +		tty_flip_buffer_push(&port->port);
>  	}
>  
> -	tty_flip_buffer_push(&port->port);
>  }
>  
>  static int set_control_lines(struct usb_device *dev, u8 value)

Johan
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