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@xxxxxxxxx>
---
v2: make sure to handle B0
drivers/usb/serial/generic.c | 31 +++++++++++++++++++++++++++++++
drivers/usb/serial/usb-serial.c | 2 ++
include/linux/usb/serial.h | 3 +++
3 files changed, 36 insertions(+)
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 297665f..ba45170 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)
{
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 31d2768..60caf9c 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1333,6 +1333,8 @@ static void usb_serial_operations_init(struct usb_serial_driver *device)
set_to_generic_if_null(device, close);
set_to_generic_if_null(device, write_room);
set_to_generic_if_null(device, chars_in_buffer);
+ if (device->tx_empty)
+ set_to_generic_if_null(device, wait_until_sent);
set_to_generic_if_null(device, read_bulk_callback);
set_to_generic_if_null(device, write_bulk_callback);
set_to_generic_if_null(device, process_read_urb);
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index afbb7ee..302ddf5 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -269,6 +269,7 @@ struct usb_serial_driver {
void (*break_ctl)(struct tty_struct *tty, int break_state);
int (*chars_in_buffer)(struct tty_struct *tty);
void (*wait_until_sent)(struct tty_struct *tty, long timeout);
+ bool (*tx_empty)(struct usb_serial_port *port);
void (*throttle)(struct tty_struct *tty);
void (*unthrottle)(struct tty_struct *tty);
int (*tiocmget)(struct tty_struct *tty);
@@ -328,6 +329,8 @@ extern void usb_serial_generic_close(struct usb_serial_port *port);
extern int usb_serial_generic_resume(struct usb_serial *serial);
extern int usb_serial_generic_write_room(struct tty_struct *tty);
extern int usb_serial_generic_chars_in_buffer(struct tty_struct *tty);
+extern void usb_serial_generic_wait_until_sent(struct tty_struct *tty,
+ long timeout);
extern void usb_serial_generic_read_bulk_callback(struct urb *urb);
extern void usb_serial_generic_write_bulk_callback(struct urb *urb);
extern void usb_serial_generic_throttle(struct tty_struct *tty);
--
1.8.2.1
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
