From ian.abbott@mev.co.uk Mon Jul 4 10:10:04 2005 Message-ID: <42C93ED2.1060200@mev.co.uk> Date: Mon, 04 Jul 2005 14:51:14 +0100 From: Ian Abbott To: Greg KH Subject: USB: ftdi_sio: Update RTS and DTR simultaneously ftdi_sio: Update RTS and DTR simultaneously, using a single control URB instead of separate control URBs for RTS and DTR. Reinhard Bergmann observed time differences of up to 680 ms with his application on a 2.4.22 kernel when RTS and DTR were updated using separate control URBs, which is unacceptable. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/ftdi_sio.c | 138 +++++++++++++----------------------------- 1 files changed, 43 insertions(+), 95 deletions(-) --- gregkh-2.6.orig/drivers/usb/serial/ftdi_sio.c 2005-07-27 14:54:48.000000000 -0700 +++ gregkh-2.6/drivers/usb/serial/ftdi_sio.c 2005-07-27 14:55:11.000000000 -0700 @@ -596,62 +596,59 @@ return(ftdi_232bm_baud_base_to_divisor(baud, 48000000)); } -static int set_rts(struct usb_serial_port *port, int high_or_low) +#define set_mctrl(port, set) update_mctrl((port), (set), 0) +#define clear_mctrl(port, clear) update_mctrl((port), 0, (clear)) + +static int update_mctrl(struct usb_serial_port *port, unsigned int set, unsigned int clear) { struct ftdi_private *priv = usb_get_serial_port_data(port); char *buf; - unsigned ftdi_high_or_low; + unsigned urb_value; int rv; - - buf = kmalloc(1, GFP_NOIO); - if (!buf) - return -ENOMEM; - - if (high_or_low) { - ftdi_high_or_low = FTDI_SIO_SET_RTS_HIGH; - priv->last_dtr_rts |= TIOCM_RTS; - } else { - ftdi_high_or_low = FTDI_SIO_SET_RTS_LOW; - priv->last_dtr_rts &= ~TIOCM_RTS; - } - rv = usb_control_msg(port->serial->dev, - usb_sndctrlpipe(port->serial->dev, 0), - FTDI_SIO_SET_MODEM_CTRL_REQUEST, - FTDI_SIO_SET_MODEM_CTRL_REQUEST_TYPE, - ftdi_high_or_low, priv->interface, - buf, 0, WDR_TIMEOUT); - - kfree(buf); - return rv; -} + if (((set | clear) & (TIOCM_DTR | TIOCM_RTS)) == 0) { + dbg("%s - DTR|RTS not being set|cleared", __FUNCTION__); + return 0; /* no change */ + } -static int set_dtr(struct usb_serial_port *port, int high_or_low) -{ - struct ftdi_private *priv = usb_get_serial_port_data(port); - char *buf; - unsigned ftdi_high_or_low; - int rv; - buf = kmalloc(1, GFP_NOIO); - if (!buf) + if (!buf) { return -ENOMEM; - - if (high_or_low) { - ftdi_high_or_low = FTDI_SIO_SET_DTR_HIGH; - priv->last_dtr_rts |= TIOCM_DTR; - } else { - ftdi_high_or_low = FTDI_SIO_SET_DTR_LOW; - priv->last_dtr_rts &= ~TIOCM_DTR; } + + clear &= ~set; /* 'set' takes precedence over 'clear' */ + urb_value = 0; + if (clear & TIOCM_DTR) + urb_value |= FTDI_SIO_SET_DTR_LOW; + if (clear & TIOCM_RTS) + urb_value |= FTDI_SIO_SET_RTS_LOW; + if (set & TIOCM_DTR) + urb_value |= FTDI_SIO_SET_DTR_HIGH; + if (set & TIOCM_RTS) + urb_value |= FTDI_SIO_SET_RTS_HIGH; rv = usb_control_msg(port->serial->dev, usb_sndctrlpipe(port->serial->dev, 0), FTDI_SIO_SET_MODEM_CTRL_REQUEST, FTDI_SIO_SET_MODEM_CTRL_REQUEST_TYPE, - ftdi_high_or_low, priv->interface, + urb_value, priv->interface, buf, 0, WDR_TIMEOUT); kfree(buf); + if (rv < 0) { + err("%s Error from MODEM_CTRL urb: DTR %s, RTS %s", + __FUNCTION__, + (set & TIOCM_DTR) ? "HIGH" : + (clear & TIOCM_DTR) ? "LOW" : "unchanged", + (set & TIOCM_RTS) ? "HIGH" : + (clear & TIOCM_RTS) ? "LOW" : "unchanged"); + } else { + dbg("%s - DTR %s, RTS %s", __FUNCTION__, + (set & TIOCM_DTR) ? "HIGH" : + (clear & TIOCM_DTR) ? "LOW" : "unchanged", + (set & TIOCM_RTS) ? "HIGH" : + (clear & TIOCM_RTS) ? "LOW" : "unchanged"); + priv->last_dtr_rts = (priv->last_dtr_rts & ~clear) | set; + } return rv; } @@ -1222,12 +1219,7 @@ /* FIXME: Flow control might be enabled, so it should be checked - we have no control of defaults! */ /* Turn on RTS and DTR since we are not flow controlling by default */ - if (set_dtr(port, HIGH) < 0) { - err("%s Error from DTR HIGH urb", __FUNCTION__); - } - if (set_rts(port, HIGH) < 0){ - err("%s Error from RTS HIGH urb", __FUNCTION__); - } + set_mctrl(port, TIOCM_DTR | TIOCM_RTS); /* Not throttled */ spin_lock_irqsave(&priv->rx_lock, flags); @@ -1277,14 +1269,8 @@ err("error from flowcontrol urb"); } - /* drop DTR */ - if (set_dtr(port, LOW) < 0){ - err("Error from DTR LOW urb"); - } - /* drop RTS */ - if (set_rts(port, LOW) < 0) { - err("Error from RTS LOW urb"); - } + /* drop RTS and DTR */ + clear_mctrl(port, TIOCM_DTR | TIOCM_RTS); } /* Note change no line if hupcl is off */ /* cancel any scheduled reading */ @@ -1815,25 +1801,14 @@ err("%s error from disable flowcontrol urb", __FUNCTION__); } /* Drop RTS and DTR */ - if (set_dtr(port, LOW) < 0){ - err("%s Error from DTR LOW urb", __FUNCTION__); - } - if (set_rts(port, LOW) < 0){ - err("%s Error from RTS LOW urb", __FUNCTION__); - } - + clear_mctrl(port, TIOCM_DTR | TIOCM_RTS); } else { /* set the baudrate determined before */ if (change_speed(port)) { err("%s urb failed to set baurdrate", __FUNCTION__); } /* Ensure RTS and DTR are raised */ - else if (set_dtr(port, HIGH) < 0){ - err("%s Error from DTR HIGH urb", __FUNCTION__); - } - else if (set_rts(port, HIGH) < 0){ - err("%s Error from RTS HIGH urb", __FUNCTION__); - } + set_mctrl(port, TIOCM_DTR | TIOCM_RTS); } /* Set flow control */ @@ -1945,35 +1920,8 @@ static int ftdi_tiocmset(struct usb_serial_port *port, struct file * file, unsigned int set, unsigned int clear) { - int ret; - dbg("%s TIOCMSET", __FUNCTION__); - if (set & TIOCM_DTR){ - if ((ret = set_dtr(port, HIGH)) < 0) { - err("Urb to set DTR failed"); - return(ret); - } - } - if (set & TIOCM_RTS) { - if ((ret = set_rts(port, HIGH)) < 0){ - err("Urb to set RTS failed"); - return(ret); - } - } - - if (clear & TIOCM_DTR){ - if ((ret = set_dtr(port, LOW)) < 0){ - err("Urb to unset DTR failed"); - return(ret); - } - } - if (clear & TIOCM_RTS) { - if ((ret = set_rts(port, LOW)) < 0){ - err("Urb to unset RTS failed"); - return(ret); - } - } - return(0); + return update_mctrl(port, set, clear); }