@@ -30,6 +30,7 @@ struct rpmsg_tty_port {
struct tty_port port; /* TTY port data */
int id; /* TTY rpmsg index */
struct rpmsg_device *rpdev; /* rpmsg device */
+ bool flow_stopped; /* remote device flow control */
};
static int rpmsg_tty_cb(struct rpmsg_device *rpdev, void *data, int len, void *priv, u32 src)
@@ -106,6 +107,9 @@ static unsigned int rpmsg_tty_write_room(struct tty_struct *tty)
struct rpmsg_tty_port *cport = tty->driver_data;
int size;
+ if (cport->flow_stopped)
+ return 0;
+
size = rpmsg_get_mtu(cport->rpdev->ept);
if (size < 0)
return 0;
@@ -118,6 +122,28 @@ static void rpmsg_tty_hangup(struct tty_struct *tty)
tty_port_hangup(tty->port);
}
+static void rpmsg_tty_throttle(struct tty_struct *tty)
+{
+ struct rpmsg_tty_port *cport = tty->driver_data;
+ int ret;
+
+ /* Disable remote transmission */
+ ret = rpmsg_set_flow_control(cport->rpdev->ept, RPMSG_ADDR_ANY, 0);
+ if (ret && ret != ENXIO)
+ dev_err(tty->dev, "cannot send control (%d)\n", ret);
+};
+
+static void rpmsg_tty_unthrottle(struct tty_struct *tty)
+{
+ struct rpmsg_tty_port *cport = tty->driver_data;
+ int ret;
+
+ /* Enable remote transmission */
+ ret = rpmsg_set_flow_control(cport->rpdev->ept, RPMSG_ADDR_ANY, 1);
+ if (ret && ret != ENXIO)
+ dev_err(tty->dev, "cannot send control (%d)\n", ret);
+};
+
static const struct tty_operations rpmsg_tty_ops = {
.install = rpmsg_tty_install,
.open = rpmsg_tty_open,
@@ -126,6 +152,8 @@ static const struct tty_operations rpmsg_tty_ops = {
.write_room = rpmsg_tty_write_room,
.hangup = rpmsg_tty_hangup,
.cleanup = rpmsg_tty_cleanup,
+ .throttle = rpmsg_tty_throttle,
+ .unthrottle = rpmsg_tty_unthrottle,
};
static struct rpmsg_tty_port *rpmsg_tty_alloc_cport(void)
@@ -162,11 +190,32 @@ static void rpmsg_tty_destruct_port(struct tty_port *port)
kfree(cport);
}
+static void rpmsg_tty_dtr_rts(struct tty_port *port, int raise)
+{
+ if (!port->tty)
+ return;
+
+ if (raise)
+ rpmsg_tty_unthrottle(port->tty);
+ else
+ rpmsg_tty_throttle(port->tty);
+}
+
static const struct tty_port_operations rpmsg_tty_port_ops = {
.destruct = rpmsg_tty_destruct_port,
+ .dtr_rts = rpmsg_tty_dtr_rts,
};
+static int rpmsg_tty_dsr_cts(struct rpmsg_device *rpdev, void *priv, u32 state)
+{
+ struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev);
+
+ cport->flow_stopped = !state;
+
+ return 0;
+}
+
static int rpmsg_tty_probe(struct rpmsg_device *rpdev)
{
struct rpmsg_tty_port *cport;
@@ -225,6 +274,7 @@ static struct rpmsg_driver rpmsg_tty_rpmsg_drv = {
.probe = rpmsg_tty_probe,
.callback = rpmsg_tty_cb,
.remove = rpmsg_tty_remove,
+ .signals = rpmsg_tty_dsr_cts,
};
static int __init rpmsg_tty_init(void)
Add Software flow control support based on the RPMsg flow control channel. Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> --- drivers/tty/rpmsg_tty.c | 50 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+)