1 files changed, 91 insertions, 27 deletions

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 051c3a77b41b..3bfcc7b9f861 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -264,7 +264,7 @@
 /*
  * Version Information
  */
-#define DRIVER_VERSION "v1.4.1"
+#define DRIVER_VERSION "v1.4.2"
 #define DRIVER_AUTHOR "Greg Kroah-Hartman <greg@kroah.com>, Bill Ryder <bryder@sgi.com>, Kuba Ober <kuba@mareimbrium.org>"
 #define DRIVER_DESC "USB FTDI Serial Converters Driver"
 
@@ -687,6 +687,8 @@ struct ftdi_private {
         char prev_status, diff_status;        /* Used for TIOCMIWAIT */
         __u8 rx_flags;          /* receive state flags (throttling) */
         spinlock_t rx_lock;     /* spinlock for receive state */
+        struct work_struct rx_work;
+        int rx_processed;
 
         __u16 interface;        /* FT2232C port interface (0 for FT232/245) */
 
@@ -717,7 +719,7 @@ static int  ftdi_write_room		(struct usb_serial_port *port);
 static int  ftdi_chars_in_buffer        (struct usb_serial_port *port);
 static void ftdi_write_bulk_callback    (struct urb *urb, struct pt_regs *regs);
 static void ftdi_read_bulk_callback     (struct urb *urb, struct pt_regs *regs);
-static void ftdi_process_read           (struct usb_serial_port *port);
+static void ftdi_process_read           (void *param);
 static void ftdi_set_termios            (struct usb_serial_port *port, struct termios * old);
 static int  ftdi_tiocmget               (struct usb_serial_port *port, struct file *file);
 static int  ftdi_tiocmset               (struct usb_serial_port *port, struct file * file, unsigned int set, unsigned int clear);
@@ -1387,6 +1389,8 @@ static int ftdi_common_startup (struct usb_serial *serial)
                 port->read_urb->transfer_buffer_length = BUFSZ;
         }
 
+        INIT_WORK(&priv->rx_work, ftdi_process_read, port);
+
         /* Free port's existing write urb and transfer buffer. */
         if (port->write_urb) {
                 usb_free_urb (port->write_urb);
@@ -1617,6 +1621,7 @@ static int  ftdi_open (struct usb_serial_port *port, struct file *filp)
         spin_unlock_irqrestore(&priv->rx_lock, flags);
 
         /* Start reading from the device */
+        priv->rx_processed = 0;
         usb_fill_bulk_urb(port->read_urb, dev,
                       usb_rcvbulkpipe(dev, port->bulk_in_endpointAddress),
                       port->read_urb->transfer_buffer, port->read_urb->transfer_buffer_length,
@@ -1667,6 +1672,10 @@ static void ftdi_close (struct usb_serial_port *port, struct file *filp)
                         err("Error from RTS LOW urb");
                 }
         } /* Note change no line if hupcl is off */
+
+        /* cancel any scheduled reading */
+        cancel_delayed_work(&priv->rx_work);
+        flush_scheduled_work();
         
         /* shutdown our bulk read */
         if (port->read_urb)
@@ -1862,23 +1871,14 @@ static void ftdi_read_bulk_callback (struct urb *urb, struct pt_regs *regs)
                 return;
         }
 
-        /* If throttled, delay receive processing until unthrottled. */
-        spin_lock(&priv->rx_lock);
-        if (priv->rx_flags & THROTTLED) {
-                dbg("Deferring read urb processing until unthrottled");
-                priv->rx_flags |= ACTUALLY_THROTTLED;
-                spin_unlock(&priv->rx_lock);
-                return;
-        }
-        spin_unlock(&priv->rx_lock);
-
         ftdi_process_read(port);
 
 } /* ftdi_read_bulk_callback */
 
 
-static void ftdi_process_read (struct usb_serial_port *port)
+static void ftdi_process_read (void *param)
 { /* ftdi_process_read */
+        struct usb_serial_port *port = (struct usb_serial_port*)param;
         struct urb *urb;
         struct tty_struct *tty;
         struct ftdi_private *priv;
@@ -1889,6 +1889,7 @@ static void ftdi_process_read (struct usb_serial_port *port)
         int result;
         int need_flip;
         int packet_offset;
+        unsigned long flags;
 
         dbg("%s - port %d", __FUNCTION__, port->number);
 
@@ -1915,12 +1916,18 @@ static void ftdi_process_read (struct usb_serial_port *port)
 
         data = urb->transfer_buffer;
 
-        /* The first two bytes of every read packet are status */
-        if (urb->actual_length > 2) {
-                usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);
+        if (priv->rx_processed) {
+                dbg("%s - already processed: %d bytes, %d remain", __FUNCTION__,
+                                priv->rx_processed,
+                                urb->actual_length - priv->rx_processed);
         } else {
-                dbg("Status only: %03oo %03oo",data[0],data[1]);
-        }
+                /* The first two bytes of every read packet are status */
+                if (urb->actual_length > 2) {
+                        usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);
+                } else {
+                        dbg("Status only: %03oo %03oo",data[0],data[1]);
+                }
+        }
 
 
         /* TO DO -- check for hung up line and handle appropriately: */
@@ -1929,8 +1936,12 @@ static void ftdi_process_read (struct usb_serial_port *port)
         /* if CD is dropped and the line is not CLOCAL then we should hangup */
 
         need_flip = 0;
-        for (packet_offset=0; packet_offset < urb->actual_length; packet_offset += PKTSZ) {
+        for (packet_offset = priv->rx_processed; packet_offset < urb->actual_length; packet_offset += PKTSZ) {
+                int length;
+
                 /* Compare new line status to the old one, signal if different */
+                /* N.B. packet may be processed more than once, but differences
+                 * are only processed once.  */
                 if (priv != NULL) {
                         char new_status = data[packet_offset+0] & FTDI_STATUS_B0_MASK;
                         if (new_status != priv->prev_status) {
@@ -1940,6 +1951,35 @@ static void ftdi_process_read (struct usb_serial_port *port)
                         }
                 }
 
+                length = min(PKTSZ, urb->actual_length-packet_offset)-2;
+                if (length < 0) {
+                        err("%s - bad packet length: %d", __FUNCTION__, length+2);
+                        length = 0;
+                }
+
+                /* have to make sure we don't overflow the buffer
+                   with tty_insert_flip_char's */
+                if (tty->flip.count+length > TTY_FLIPBUF_SIZE) {
+                        tty_flip_buffer_push(tty);
+                        need_flip = 0;
+
+                        if (tty->flip.count != 0) {
+                                /* flip didn't work, this happens when ftdi_process_read() is
+                                 * called from ftdi_unthrottle, because TTY_DONT_FLIP is set */
+                                dbg("%s - flip buffer push failed", __FUNCTION__);
+                                break;
+                        }
+                }
+                if (priv->rx_flags & THROTTLED) {
+                        dbg("%s - throttled", __FUNCTION__);
+                        break;
+                }
+                if (tty->ldisc.receive_room(tty)-tty->flip.count < length) {
+                        /* break out & wait for throttling/unthrottling to happen */
+                        dbg("%s - receive room low", __FUNCTION__);
+                        break;
+                }
+
                 /* Handle errors and break */
                 error_flag = TTY_NORMAL;
                 /* Although the device uses a bitmask and hence can have multiple */
@@ -1962,13 +2002,8 @@ static void ftdi_process_read (struct usb_serial_port *port)
                         error_flag = TTY_FRAME;
                         dbg("FRAMING error");
                 }
-                if (urb->actual_length > packet_offset + 2) {
-                        for (i = 2; (i < PKTSZ) && ((i+packet_offset) < urb->actual_length); ++i) {
-                                /* have to make sure we don't overflow the buffer
-                                  with tty_insert_flip_char's */
-                                if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-                                        tty_flip_buffer_push(tty);
-                                }
+                if (length > 0) {
+                        for (i = 2; i < length+2; i++) {
                                 /* Note that the error flag is duplicated for 
                                    every character received since we don't know
                                    which character it applied to */
@@ -2005,6 +2040,35 @@ static void ftdi_process_read (struct usb_serial_port *port)
                 tty_flip_buffer_push(tty);
         }
 
+        if (packet_offset < urb->actual_length) {
+                /* not completely processed - record progress */
+                priv->rx_processed = packet_offset;
+                dbg("%s - incomplete, %d bytes processed, %d remain",
+                                __FUNCTION__, packet_offset,
+                                urb->actual_length - packet_offset);
+                /* check if we were throttled while processing */
+                spin_lock_irqsave(&priv->rx_lock, flags);
+                if (priv->rx_flags & THROTTLED) {
+                        priv->rx_flags |= ACTUALLY_THROTTLED;
+                        spin_unlock_irqrestore(&priv->rx_lock, flags);
+                        dbg("%s - deferring remainder until unthrottled",
+                                        __FUNCTION__);
+                        return;
+                }
+                spin_unlock_irqrestore(&priv->rx_lock, flags);
+                /* if the port is closed stop trying to read */
+                if (port->open_count > 0){
+                        /* delay processing of remainder */
+                        schedule_delayed_work(&priv->rx_work, 1);
+                } else {
+                        dbg("%s - port is closed", __FUNCTION__);
+                }
+                return;
+        }
+
+        /* urb is completely processed */
+        priv->rx_processed = 0;
+
         /* if the port is closed stop trying to read */
         if (port->open_count > 0){
                 /* Continue trying to always read  */
@@ -2444,7 +2508,7 @@ static void ftdi_unthrottle (struct usb_serial_port *port)
         spin_unlock_irqrestore(&priv->rx_lock, flags);
 
         if (actually_throttled)
-                ftdi_process_read(port);
+                schedule_work(&priv->rx_work);
 }
 
 static int __init ftdi_init (void)