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authorJohan Hovold <jhovold@gmail.com>2013-05-08 19:51:43 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-17 04:32:21 +0400
commitdcf0105039660e951dfea348d317043d17988dfc (patch)
tree17b7748bf83e08da5da530a257a81cc044110e91 /drivers/usb/serial/generic.c
parent0693196fe7bbb5e6cafd255dfce91ff6d10bc18f (diff)
downloadlinux-dcf0105039660e951dfea348d317043d17988dfc.tar.xz
USB: serial: add generic wait_until_sent implementation
Add generic wait_until_sent implementation which polls for empty hardware buffers using the new port-operation tx_empty. The generic implementation will be used for all sub-drivers that implement tx_empty but does not define wait_until_sent. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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)
{