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path: root/drivers/usb/serial/generic.c
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Diffstat (limited to 'drivers/usb/serial/generic.c')
-rw-r--r--drivers/usb/serial/generic.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 297665fdd16d..ba45170c78e5 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -253,6 +253,37 @@ int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
}
EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer);
+void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ unsigned int bps;
+ unsigned long period;
+ unsigned long expire;
+
+ bps = tty_get_baud_rate(tty);
+ if (!bps)
+ bps = 9600; /* B0 */
+ /*
+ * Use a poll-period of roughly the time it takes to send one
+ * character or at least one jiffy.
+ */
+ period = max_t(unsigned long, (10 * HZ / bps), 1);
+ period = min_t(unsigned long, period, timeout);
+
+ dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
+ __func__, jiffies_to_msecs(timeout),
+ jiffies_to_msecs(period));
+ expire = jiffies + timeout;
+ while (!port->serial->type->tx_empty(port)) {
+ schedule_timeout_interruptible(period);
+ if (signal_pending(current))
+ break;
+ if (time_after(jiffies, expire))
+ break;
+ }
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent);
+
static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
int index, gfp_t mem_flags)
{