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| author | Johan Hovold <jhovold@gmail.com> | 2013-05-08 17:51:43 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-17 02:32:21 +0200 |
| commit | dcf0105039660e951dfea348d317043d17988dfc (patch) | |
| tree | 17b7748bf83e08da5da530a257a81cc044110e91 /drivers/usb/serial/generic.c | |
| parent | USB: serial: add wait_until_sent operation (diff) | |
| download | linux-dcf0105039660e951dfea348d317043d17988dfc.tar.xz linux-dcf0105039660e951dfea348d317043d17988dfc.zip | |
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.c | 31 |
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) { |