Greg --

Here is the patch adding a circular buffer to pl2303
updated to 2.6.9-rc1.  Phil and I both tested this.
(Phil tested a slightly different earlier version.)

This fixes the carriage return newline problem Olaf
Hering reported and helps Phil with hotsyncing his
phone.  This patch also fixes a problem that would
sometimes leave a pl2303 port unable to send data,
reporting "already writing", after closing the port
while writing was in progress.  This happened about
1/3 of the time in my tests with the stock 2.6.9-rc1
pl2303 driver.

If it looks ok to you, please apply.

Thanks,
-- Al

Change Log

- Added a circular write buffer, protected by the
  existing spin lock.

- Write_room and chars_in_buffer now report room and
  chars in the circular buffer.

- Added a "bounce buffer" when transfering data from
  user space to the circular buffer--needed for locking.

- Replaced (urb->status != -EINPROGRESS) with a private
  write_urb_in_use flag protected by the existing spin
  lock.  Clear this flag when the urb is unlinked.

- Free memory on failed startup.

- These changes make ONLCR mapping work and fix a bug
  that would sometimes leave the port unable to write,
  reporting "already writing", after closing the port
  while writing was in progress.

Signed-off-by: Al Borchers <[EMAIL PROTECTED]>

diff --exclude-from=dontdiff -urp linux-2.6.9-rc1.orig/drivers/usb/serial/pl2303.c 
linux-2.6.9-rc1.new/drivers/usb/serial/pl2303.c
--- linux-2.6.9-rc1.orig/drivers/usb/serial/pl2303.c    2004-08-27 10:12:35.000000000 
-0500
+++ linux-2.6.9-rc1.new/drivers/usb/serial/pl2303.c     2004-08-28 15:44:17.000000000 
-0500
@@ -55,11 +55,24 @@
 /*
  * Version Information
  */
-#define DRIVER_VERSION "v0.11"
+#define DRIVER_VERSION "v0.12"
 #define DRIVER_DESC "Prolific PL2303 USB to serial adaptor driver"
 
 static int debug;
 
+#define PL2303_BUF_SIZE                1024
+#define PL2303_TMP_BUF_SIZE    1024
+
+static char pl2303_tmp_buf[PL2303_TMP_BUF_SIZE];
+static DECLARE_MUTEX(pl2303_tmp_buf_sem);
+
+struct pl2303_buf {
+       unsigned int    buf_size;
+       char            *buf_buf;
+       char            *buf_get;
+       char            *buf_put;
+};
+
 static struct usb_device_id id_table [] = {
        { USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID) },
        { USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_RSAQ2) },
@@ -134,12 +147,23 @@ static void pl2303_read_bulk_callback (s
 static void pl2303_write_bulk_callback (struct urb *urb, struct pt_regs *regs);
 static int pl2303_write (struct usb_serial_port *port, int from_user,
                         const unsigned char *buf, int count);
+static void pl2303_send (struct usb_serial_port *port);
+static int pl2303_write_room(struct usb_serial_port *port);
+static int pl2303_chars_in_buffer(struct usb_serial_port *port);
 static void pl2303_break_ctl(struct usb_serial_port *port,int break_state);
 static int pl2303_tiocmget (struct usb_serial_port *port, struct file *file);
 static int pl2303_tiocmset (struct usb_serial_port *port, struct file *file,
                            unsigned int set, unsigned int clear);
 static int pl2303_startup (struct usb_serial *serial);
 static void pl2303_shutdown (struct usb_serial *serial);
+static struct pl2303_buf *pl2303_buf_alloc(unsigned int size);
+static void pl2303_buf_free(struct pl2303_buf *pb);
+static unsigned int pl2303_buf_data_avail(struct pl2303_buf *pb);
+static unsigned int pl2303_buf_space_avail(struct pl2303_buf *pb);
+static unsigned int pl2303_buf_put(struct pl2303_buf *pb, const char *buf,
+       unsigned int count);
+static unsigned int pl2303_buf_get(struct pl2303_buf *pb, char *buf,
+       unsigned int count);
 
 
 /* All of the device info needed for the PL2303 SIO serial converter */
@@ -162,6 +186,8 @@ static struct usb_serial_device_type pl2
        .read_bulk_callback =   pl2303_read_bulk_callback,
        .read_int_callback =    pl2303_read_int_callback,
        .write_bulk_callback =  pl2303_write_bulk_callback,
+       .write_room =           pl2303_write_room,
+       .chars_in_buffer =      pl2303_chars_in_buffer,
        .attach =               pl2303_startup,
        .shutdown =             pl2303_shutdown,
 };
@@ -174,6 +200,8 @@ enum pl2303_type {
 
 struct pl2303_private {
        spinlock_t lock;
+       struct pl2303_buf *buf;
+       int write_urb_in_use;
        wait_queue_head_t delta_msr_wait;
        u8 line_control;
        u8 line_status;
@@ -201,14 +229,28 @@ static int pl2303_startup (struct usb_se
        for (i = 0; i < serial->num_ports; ++i) {
                priv = kmalloc (sizeof (struct pl2303_private), GFP_KERNEL);
                if (!priv)
-                       return -ENOMEM;
+                       goto cleanup;
                memset (priv, 0x00, sizeof (struct pl2303_private));
                spin_lock_init(&priv->lock);
+               priv->buf = pl2303_buf_alloc(PL2303_BUF_SIZE);
+               if (priv->buf == NULL) {
+                       kfree(priv);
+                       goto cleanup;
+               }
                init_waitqueue_head(&priv->delta_msr_wait);
                priv->type = type;
                usb_set_serial_port_data(serial->port[i], priv);
        }
        return 0;
+
+cleanup:
+       for (--i; i>=0; --i) {
+               priv = usb_get_serial_port_data(serial->port[i]);
+               pl2303_buf_free(priv->buf);
+               kfree(priv);
+               usb_set_serial_port_data(serial->port[i], NULL);
+       }
+       return -ENOMEM;
 }
 
 static int set_control_lines (struct usb_device *dev, u8 value)
@@ -224,40 +266,109 @@ static int set_control_lines (struct usb
 
 static int pl2303_write (struct usb_serial_port *port, int from_user,  const unsigned 
char *buf, int count)
 {
-       int result;
+       struct pl2303_private *priv = usb_get_serial_port_data(port);
+       unsigned long flags;
 
        dbg("%s - port %d, %d bytes", __FUNCTION__, port->number, count);
 
        if (!count)
                return count;
 
-       if (port->write_urb->status == -EINPROGRESS) {
-               dbg("%s - already writing", __FUNCTION__);
-               return 0;
-       }
-
-       count = (count > port->bulk_out_size) ? port->bulk_out_size : count;
        if (from_user) {
-               if (copy_from_user (port->write_urb->transfer_buffer, buf, count))
+               if (count > PL2303_TMP_BUF_SIZE)
+                       count = PL2303_TMP_BUF_SIZE;
+               down(&pl2303_tmp_buf_sem);
+               if (copy_from_user(pl2303_tmp_buf, buf, count)) {
+                       up(&pl2303_tmp_buf_sem);
                        return -EFAULT;
-       } else {
-               memcpy (port->write_urb->transfer_buffer, buf, count);
+               }
+               buf = pl2303_tmp_buf;
        }
-       
+
+       spin_lock_irqsave(&priv->lock, flags);
+       count = pl2303_buf_put(priv->buf, buf, count);
+       spin_unlock_irqrestore(&priv->lock, flags);
+
+       if (from_user)
+               up(&pl2303_tmp_buf_sem);
+
+       pl2303_send(port);
+
+       return count;
+}
+
+static void pl2303_send(struct usb_serial_port *port)
+{
+       int count, result;
+       struct pl2303_private *priv = usb_get_serial_port_data(port);
+       unsigned long flags;
+
+       dbg("%s - port %d", __FUNCTION__, port->number);
+
+       spin_lock_irqsave(&priv->lock, flags);
+
+       if (priv->write_urb_in_use) {
+               spin_unlock_irqrestore(&priv->lock, flags);
+               return;
+       }
+
+       count = pl2303_buf_get(priv->buf, port->write_urb->transfer_buffer,
+               port->bulk_out_size);
+
+       if (count == 0) {
+               spin_unlock_irqrestore(&priv->lock, flags);
+               return;
+       }
+
+       priv->write_urb_in_use = 1;
+
+       spin_unlock_irqrestore(&priv->lock, flags);
+
        usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, 
port->write_urb->transfer_buffer);
 
        port->write_urb->transfer_buffer_length = count;
        port->write_urb->dev = port->serial->dev;
        result = usb_submit_urb (port->write_urb, GFP_ATOMIC);
-       if (result)
+       if (result) {
                dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", 
__FUNCTION__, result);
-       else
-               result = count;
+               priv->write_urb_in_use = 0;
+               // TODO: reschedule pl2303_send
+       }
 
-       return result;
+       schedule_work(&port->work);
+}
+
+static int pl2303_write_room(struct usb_serial_port *port)
+{
+       struct pl2303_private *priv = usb_get_serial_port_data(port);
+       int room = 0;
+       unsigned long flags;
+
+       dbg("%s - port %d", __FUNCTION__, port->number);
+
+       spin_lock_irqsave(&priv->lock, flags);
+       room = pl2303_buf_space_avail(priv->buf);
+       spin_unlock_irqrestore(&priv->lock, flags);
+
+       dbg("%s - returns %d", __FUNCTION__, room);
+       return room;
 }
 
+static int pl2303_chars_in_buffer(struct usb_serial_port *port)
+{
+       struct pl2303_private *priv = usb_get_serial_port_data(port);
+       int chars = 0;
+       unsigned long flags;
 
+       dbg("%s - port %d", __FUNCTION__, port->number);
+
+       spin_lock_irqsave(&priv->lock, flags);
+       chars = pl2303_buf_data_avail(priv->buf);
+       spin_unlock_irqrestore(&priv->lock, flags);
+
+       dbg("%s - returns %d", __FUNCTION__, chars);
+       return chars;
+}
 
 static void pl2303_set_termios (struct usb_serial_port *port, struct termios 
*old_termios)
 {
@@ -422,7 +533,7 @@ static void pl2303_set_termios (struct u
        }
 
        kfree (buf);
-} 
+}
 
 static int pl2303_open (struct usb_serial_port *port, struct file *filp)
 {
@@ -461,7 +572,7 @@ static int pl2303_open (struct usb_seria
        FISH (VENDOR_READ_REQUEST_TYPE, VENDOR_READ_REQUEST, 0x8383, 0);
        SOUP (VENDOR_WRITE_REQUEST_TYPE, VENDOR_WRITE_REQUEST, 0, 1);
        SOUP (VENDOR_WRITE_REQUEST_TYPE, VENDOR_WRITE_REQUEST, 1, 0);
- 
+
        if (priv->type == HX) {
                /* HX chip */
                SOUP (VENDOR_WRITE_REQUEST_TYPE, VENDOR_WRITE_REQUEST, 2, 0x44);
@@ -672,12 +783,17 @@ static void pl2303_break_ctl (struct usb
 static void pl2303_shutdown (struct usb_serial *serial)
 {
        int i;
+       struct pl2303_private *priv;
 
        dbg("%s", __FUNCTION__);
 
        for (i = 0; i < serial->num_ports; ++i) {
-               kfree (usb_get_serial_port_data(serial->port[i]));
-               usb_set_serial_port_data(serial->port[i], NULL);
+               priv = usb_get_serial_port_data(serial->port[i]);
+               if (priv) {
+                       pl2303_buf_free(priv->buf);
+                       kfree(priv);
+                       usb_set_serial_port_data(serial->port[i], NULL);
+               }
        }               
 }
 
@@ -815,11 +931,23 @@ static void pl2303_read_bulk_callback (s
 static void pl2303_write_bulk_callback (struct urb *urb, struct pt_regs *regs)
 {
        struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
+       struct pl2303_private *priv = usb_get_serial_port_data(port);
        int result;
 
        dbg("%s - port %d", __FUNCTION__, port->number);
-       
-       if (urb->status) {
+
+       switch (urb->status) {
+       case 0:
+               /* success */
+               break;
+       case -ECONNRESET:
+       case -ENOENT:
+       case -ESHUTDOWN:
+               /* this urb is terminated, clean up */
+               dbg("%s - urb shutting down with status: %d", __FUNCTION__, 
urb->status);
+               priv->write_urb_in_use = 0;
+               return;
+       default:
                /* error in the urb, so we have to resubmit it */
                dbg("%s - Overflow in write", __FUNCTION__);
                dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, 
urb->status);
@@ -828,14 +956,185 @@ static void pl2303_write_bulk_callback (
                result = usb_submit_urb (port->write_urb, GFP_ATOMIC);
                if (result)
                        dev_err(&urb->dev->dev, "%s - failed resubmitting write urb, 
error %d\n", __FUNCTION__, result);
+               else
+                       return;
+       }
 
-               return;
+       priv->write_urb_in_use = 0;
+
+       /* send any buffered data */
+       pl2303_send(port);
+}
+
+
+/*
+ * pl2303_buf_alloc
+ *
+ * Allocate a circular buffer and all associated memory.
+ */
+
+static struct pl2303_buf *pl2303_buf_alloc(unsigned int size)
+{
+
+       struct pl2303_buf *pb;
+
+
+       if (size == 0)
+               return NULL;
+
+       pb = (struct pl2303_buf *)kmalloc(sizeof(struct pl2303_buf), GFP_KERNEL);
+       if (pb == NULL)
+               return NULL;
+
+       pb->buf_buf = kmalloc(size, GFP_KERNEL);
+       if (pb->buf_buf == NULL) {
+               kfree(pb);
+               return NULL;
        }
 
-       schedule_work(&port->work);
+       pb->buf_size = size;
+       pb->buf_get = pb->buf_put = pb->buf_buf;
+
+       return pb;
+
+}
+
+
+/*
+ * pl2303_buf_free
+ *
+ * Free the buffer and all associated memory.
+ */
+
+void pl2303_buf_free(struct pl2303_buf *pb)
+{
+       if (pb != NULL) {
+               if (pb->buf_buf != NULL)
+                       kfree(pb->buf_buf);
+               kfree(pb);
+       }
+}
+
+
+/*
+ * pl2303_buf_data_avail
+ *
+ * Return the number of bytes of data available in the circular
+ * buffer.
+ */
+
+static unsigned int pl2303_buf_data_avail(struct pl2303_buf *pb)
+{
+       if (pb != NULL)
+               return ((pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size);
+       else
+               return 0;
 }
 
 
+/*
+ * pl2303_buf_space_avail
+ *
+ * Return the number of bytes of space available in the circular
+ * buffer.
+ */
+
+static unsigned int pl2303_buf_space_avail(struct pl2303_buf *pb)
+{
+       if (pb != NULL)
+               return ((pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size);
+       else
+               return 0;
+}
+
+
+/*
+ * pl2303_buf_put
+ *
+ * Copy data data from a user buffer and put it into the circular buffer.
+ * Restrict to the amount of space available.
+ *
+ * Return the number of bytes copied.
+ */
+
+static unsigned int pl2303_buf_put(struct pl2303_buf *pb, const char *buf,
+       unsigned int count)
+{
+
+       unsigned int len;
+
+
+       if (pb == NULL)
+               return 0;
+
+       len  = pl2303_buf_space_avail(pb);
+       if (count > len)
+               count = len;
+
+       if (count == 0)
+               return 0;
+
+       len = pb->buf_buf + pb->buf_size - pb->buf_put;
+       if (count > len) {
+               memcpy(pb->buf_put, buf, len);
+               memcpy(pb->buf_buf, buf+len, count - len);
+               pb->buf_put = pb->buf_buf + count - len;
+       } else {
+               memcpy(pb->buf_put, buf, count);
+               if (count < len)
+                       pb->buf_put += count;
+               else /* count == len */
+                       pb->buf_put = pb->buf_buf;
+       }
+
+       return count;
+
+}
+
+
+/*
+ * pl2303_buf_get
+ *
+ * Get data from the circular buffer and copy to the given buffer.
+ * Restrict to the amount of data available.
+ *
+ * Return the number of bytes copied.
+ */
+
+static unsigned int pl2303_buf_get(struct pl2303_buf *pb, char *buf,
+       unsigned int count)
+{
+
+       unsigned int len;
+
+
+       if (pb == NULL)
+               return 0;
+
+       len = pl2303_buf_data_avail(pb);
+       if (count > len)
+               count = len;
+
+       if (count == 0)
+               return 0;
+
+       len = pb->buf_buf + pb->buf_size - pb->buf_get;
+       if (count > len) {
+               memcpy(buf, pb->buf_get, len);
+               memcpy(buf+len, pb->buf_buf, count - len);
+               pb->buf_get = pb->buf_buf + count - len;
+       } else {
+               memcpy(buf, pb->buf_get, count);
+               if (count < len)
+                       pb->buf_get += count;
+               else /* count == len */
+                       pb->buf_get = pb->buf_buf;
+       }
+
+       return count;
+
+}
+
 static int __init pl2303_init (void)
 {
        int retval;




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