Hi Johan,
Could you, please, give some feedback on the patch I've send recently?
Regards,
Peter
On Thu, May 11, 2017 at 09:12:48PM +0300, Peter Mamonov wrote:
> The patch implements TIOCSSERIAL ioctl call. The following fields of the
> `struct serial_struct` are processed:
>
> - flags: ASYNC_SPD_MASK bits are processed.
>
> - baud_base: allow a user to specify arbitrary value less or equal the
> maximum port speed. Use it later in conjunction with custom_divisor to
> calculate the desired baud rate.
>
> - custom_divisor: save a user supplied value, use it later for baud rate
> calculation.
>
> Custom baud rate may be applied using any combination of baud_base /
> custom_divisor as follows:
>
> # stty -F /dev/ttyUSBX 38400
> # setserial /dev/ttyUSBX baud_base 1000 divisor 1 spd_cust # 1 kBaud
> # setserial /dev/ttyUSBX baud_base 42000 divisor 42 spd_cust # 1 kBaud
>
> The patch is based on the code from the drivers/usb/serial/ftdi_sio.c.
>
> Signed-off-by: Peter Mamonov <pmamonov@xxxxxxxxx>
> ---
> drivers/usb/serial/mos7840.c | 99 ++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 95 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
> index e8669aae14b3..93093e27d6b5 100644
> --- a/drivers/usb/serial/mos7840.c
> +++ b/drivers/usb/serial/mos7840.c
> @@ -244,6 +244,12 @@ struct moschip_port {
> struct usb_ctrlrequest *led_dr;
>
> unsigned long flags;
> +
> + int serial_flags;
> + int baud_base;
> + int custom_divisor;
> +
> + struct mutex cfg_lock;
> };
>
> /*
> @@ -1554,6 +1560,7 @@ static int mos7840_tiocmset(struct tty_struct *tty,
> * this function calculates the proper baud rate divisor for the specified
> * baud rate.
> *****************************************************************************/
> +#define MAX_BAUD_RATE 3145728
> static int mos7840_calc_baud_rate_divisor(struct usb_serial_port *port,
> int baudRate, int *divisor,
> __u16 *clk_sel_val)
> @@ -1582,8 +1589,8 @@ static int mos7840_calc_baud_rate_divisor(struct usb_serial_port *port,
> } else if ((baudRate > 921600) && (baudRate <= 1572864)) {
> *divisor = 1572864 / baudRate;
> *clk_sel_val = 0x60;
> - } else if ((baudRate > 1572864) && (baudRate <= 3145728)) {
> - *divisor = 3145728 / baudRate;
> + } else if ((baudRate > 1572864) && (baudRate <= MAX_BAUD_RATE)) {
> + *divisor = MAX_BAUD_RATE / baudRate;
> *clk_sel_val = 0x70;
> }
> return 0;
> @@ -1733,6 +1740,8 @@ static void mos7840_change_port_settings(struct tty_struct *tty,
> return;
> }
>
> + mutex_lock(&mos7840_port->cfg_lock);
> +
> lData = LCR_BITS_8;
> lStop = LCR_STOP_1;
> lParity = LCR_PAR_NONE;
> @@ -1831,6 +1840,16 @@ static void mos7840_change_port_settings(struct tty_struct *tty,
> /* Determine divisor based on baud rate */
> baud = tty_get_baud_rate(tty);
>
> + if (baud == 38400 &&
> + (mos7840_port->serial_flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST &&
> + mos7840_port->custom_divisor) {
> + baud = mos7840_port->baud_base / mos7840_port->custom_divisor;
> + dev_dbg(&port->dev, "Set custom baudrate (%d / %d) = %d",
> + mos7840_port->baud_base,
> + mos7840_port->custom_divisor,
> + baud);
> + }
> +
> if (!baud) {
> /* pick a default, any default... */
> dev_dbg(&port->dev, "%s", "Picked default baud...\n");
> @@ -1855,6 +1874,8 @@ static void mos7840_change_port_settings(struct tty_struct *tty,
> }
> dev_dbg(&port->dev, "%s - mos7840_port->shadowLCR is End %x\n", __func__,
> mos7840_port->shadowLCR);
> +
> + mutex_unlock(&mos7840_port->cfg_lock);
> }
>
> /*****************************************************************************
> @@ -1950,20 +1971,86 @@ static int mos7840_get_serial_info(struct moschip_port *mos7840_port,
>
> memset(&tmp, 0, sizeof(tmp));
>
> + mutex_lock(&mos7840_port->cfg_lock);
> +
> tmp.type = PORT_16550A;
> tmp.line = mos7840_port->port->minor;
> tmp.port = mos7840_port->port->port_number;
> tmp.irq = 0;
> + tmp.flags = mos7840_port->serial_flags;
> tmp.xmit_fifo_size = NUM_URBS * URB_TRANSFER_BUFFER_SIZE;
> - tmp.baud_base = 9600;
> + tmp.baud_base = mos7840_port->baud_base;
> + tmp.custom_divisor = mos7840_port->custom_divisor;
> tmp.close_delay = 5 * HZ;
> tmp.closing_wait = 30 * HZ;
>
> + mutex_unlock(&mos7840_port->cfg_lock);
> +
> if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
> return -EFAULT;
> return 0;
> }
>
> +static int mos7840_set_serial_info(struct tty_struct *tty,
> + struct moschip_port *priv,
> + struct serial_struct __user *newinfo)
> +{
> + struct serial_struct new_serial;
> + int old_flags = priv->serial_flags;
> + int old_divisor = priv->custom_divisor;
> + int old_base = priv->baud_base;
> +
> + if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
> + return -EFAULT;
> + mutex_lock(&priv->cfg_lock);
> +
> + if (!capable(CAP_SYS_ADMIN)) {
> + if (((new_serial.flags & ~ASYNC_USR_MASK) !=
> + (priv->serial_flags & ~ASYNC_USR_MASK))) {
> + mutex_unlock(&priv->cfg_lock);
> + return -EPERM;
> + }
> + priv->serial_flags = ((priv->serial_flags & ~ASYNC_USR_MASK) |
> + (new_serial.flags & ASYNC_USR_MASK));
> + priv->custom_divisor = new_serial.custom_divisor;
> + goto check_and_exit;
> + }
> +
> + if (new_serial.baud_base > MAX_BAUD_RATE) {
> + mutex_unlock(&priv->cfg_lock);
> + return -EINVAL;
> + }
> + /* Save user supplied value, use it later to calculate the baudrate. */
> + priv->baud_base = new_serial.baud_base;
> +
> + priv->serial_flags = ((priv->serial_flags & ~ASYNC_FLAGS) |
> + (new_serial.flags & ASYNC_FLAGS));
> + priv->custom_divisor = new_serial.custom_divisor;
> +check_and_exit:
> + if ((priv->serial_flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
> + tty->alt_speed = 57600;
> + else if ((priv->serial_flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
> + tty->alt_speed = 115200;
> + else if ((priv->serial_flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
> + tty->alt_speed = 230400;
> + else if ((priv->serial_flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
> + tty->alt_speed = 460800;
> + else
> + tty->alt_speed = 0;
> +
> + if (((old_flags & ASYNC_SPD_MASK) !=
> + (priv->serial_flags & ASYNC_SPD_MASK)) ||
> + (((priv->serial_flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST) &&
> + ((old_divisor != priv->custom_divisor) ||
> + old_base != priv->baud_base))) {
> + mutex_unlock(&priv->cfg_lock);
> + mos7840_change_port_settings(tty, priv, &tty->termios);
> + }
> +
> + mutex_unlock(&priv->cfg_lock);
> + return 0;
> +}
> +
> /*****************************************************************************
> * SerialIoctl
> * this function handles any ioctl calls to the driver
> @@ -1997,7 +2084,7 @@ static int mos7840_ioctl(struct tty_struct *tty,
>
> case TIOCSSERIAL:
> dev_dbg(&port->dev, "%s TIOCSSERIAL\n", __func__);
> - break;
> + return mos7840_set_serial_info(tty, mos7840_port, argp);
> default:
> break;
> }
> @@ -2136,6 +2223,10 @@ static int mos7840_port_probe(struct usb_serial_port *port)
> if (!mos7840_port)
> return -ENOMEM;
>
> + mutex_init(&mos7840_port->cfg_lock);
> + mos7840_port->baud_base = MAX_BAUD_RATE;
> + mos7840_port->custom_divisor = 1;
> +
> /* Initialize all port interrupt end point to port 0 int
> * endpoint. Our device has only one interrupt end point
> * common to all port */
> --
> 2.11.0
>
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