[PATCH v4 2/4] hci_uart: line discipline enhancements

[Ilya Faenson <ifaenson@broadcom.com>]

Added the ability to flow control the UART, improved the UART baud
rate setting, transferred the speeds into line discipline from the
protocol and introduced the tty init function.

Signed-off-by: Ilya Faenson <ifaenson@broadcom.com>
---
 drivers/bluetooth/hci_ldisc.c | 106 +++++++++++++++++++++++++++++++++++++++---
 drivers/bluetooth/hci_uart.h  |   7 +++
 2 files changed, 106 insertions(+), 7 deletions(-)

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index ac87346..959dd64 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -266,6 +266,85 @@ static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
 	return 0;
 }
 
+/* Flow control or un-flow control the device */
+void hci_uart_set_flow_control(struct hci_uart *hu, bool enable)
+{
+	struct tty_struct *tty = hu->tty;
+	struct ktermios ktermios;
+	int status;
+	unsigned int set = 0;
+	unsigned int clear = 0;
+
+	if (enable) {
+		/* Disable hardware flow control */
+		ktermios = tty->termios;
+		ktermios.c_cflag &= ~CRTSCTS;
+		status = tty_set_termios(tty, &ktermios);
+		BT_DBG("Disabling hardware flow control: %s", status ?
+		       "failed" : "success");
+
+		/* Clear RTS to prevent the device from sending */
+		/* Most UARTs need OUT2 to enable interrupts */
+		status = tty->driver->ops->tiocmget(tty);
+		BT_DBG("Current tiocm 0x%x", status);
+
+		set &= ~(TIOCM_OUT2 | TIOCM_RTS);
+		clear = ~set;
+		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+		       TIOCM_OUT2 | TIOCM_LOOP;
+		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+			 TIOCM_OUT2 | TIOCM_LOOP;
+		status = tty->driver->ops->tiocmset(tty, set, clear);
+		BT_DBG("Clearing RTS: %s", status ? "failed" : "success");
+	} else {
+		/* Set RTS to allow the device to send again */
+		status = tty->driver->ops->tiocmget(tty);
+		BT_DBG("Current tiocm 0x%x", status);
+
+		set |= (TIOCM_OUT2 | TIOCM_RTS);
+		clear = ~set;
+		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+		       TIOCM_OUT2 | TIOCM_LOOP;
+		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+			 TIOCM_OUT2 | TIOCM_LOOP;
+		status = tty->driver->ops->tiocmset(tty, set, clear);
+		BT_DBG("Setting RTS: %s", status ? "failed" : "success");
+
+		/* Re-enable hardware flow control */
+		ktermios = tty->termios;
+		ktermios.c_cflag |= CRTSCTS;
+		status = tty_set_termios(tty, &ktermios);
+		BT_DBG("Enabling hardware flow control: %s", status ?
+		       "failed" : "success");
+	}
+}
+
+void hci_uart_set_speeds(struct hci_uart *hu, unsigned int init_speed,
+			 unsigned int oper_speed)
+{
+	hu->init_speed = init_speed;
+	hu->oper_speed = oper_speed;
+}
+
+void hci_uart_init_tty(struct hci_uart *hu)
+{
+	struct tty_struct *tty = hu->tty;
+	struct ktermios ktermios;
+
+	/* Bring the UART into a known 8 bits no parity hw fc state */
+	ktermios = tty->termios;
+	ktermios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
+			    | INLCR | IGNCR | ICRNL | IXON);
+	ktermios.c_oflag &= ~OPOST;
+	ktermios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
+	ktermios.c_cflag &= ~(CSIZE | PARENB);
+	ktermios.c_cflag |= CS8;
+	ktermios.c_cflag |= CRTSCTS;
+
+	/* tty_set_termios() return not checked as it is always 0 */
+	tty_set_termios(tty, &ktermios);
+}
+
 void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed)
 {
 	struct tty_struct *tty = hu->tty;
@@ -273,13 +352,13 @@ void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed)
 
 	ktermios = tty->termios;
 	ktermios.c_cflag &= ~CBAUD;
-	ktermios.c_cflag |= BOTHER;
 	tty_termios_encode_baud_rate(&ktermios, speed, speed);
 
 	/* tty_set_termios() return not checked as it is always 0 */
 	tty_set_termios(tty, &ktermios);
 
-	BT_DBG("%s: New tty speed: %d", hu->hdev->name, tty->termios.c_ispeed);
+	BT_DBG("%s: New tty speeds: %d/%d", hu->hdev->name,
+	       tty->termios.c_ispeed, tty->termios.c_ospeed);
 }
 
 static int hci_uart_setup(struct hci_dev *hdev)
@@ -287,15 +366,28 @@ static int hci_uart_setup(struct hci_dev *hdev)
 	struct hci_uart *hu = hci_get_drvdata(hdev);
 	struct hci_rp_read_local_version *ver;
 	struct sk_buff *skb;
+	unsigned int speed;
 	int err;
 
+	/* Init speed if any */
+	speed = 0;
 	if (hu->proto->init_speed)
-		hci_uart_set_baudrate(hu, hu->proto->init_speed);
-
-	if (hu->proto->set_baudrate && hu->proto->oper_speed) {
-		err = hu->proto->set_baudrate(hu, hu->proto->oper_speed);
+		speed = hu->proto->init_speed;
+	else if (hu->init_speed)
+		speed = hu->init_speed;
+	if (speed)
+		hci_uart_set_baudrate(hu, speed);
+
+	/* Operational speed if any */
+	speed = 0;
+	if (hu->proto->oper_speed)
+		speed = hu->proto->oper_speed;
+	else if (hu->oper_speed)
+		speed = hu->oper_speed;
+	if (hu->proto->set_baudrate && speed) {
+		err = hu->proto->set_baudrate(hu, speed);
 		if (!err)
-			hci_uart_set_baudrate(hu, hu->proto->oper_speed);
+			hci_uart_set_baudrate(hu, speed);
 	}
 
 	if (hu->proto->setup)
diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
index e9f970c..ce9c670 100644
--- a/drivers/bluetooth/hci_uart.h
+++ b/drivers/bluetooth/hci_uart.h
@@ -85,6 +85,9 @@ struct hci_uart {
 	struct sk_buff		*tx_skb;
 	unsigned long		tx_state;
 	spinlock_t		rx_lock;
+
+	unsigned int init_speed;
+	unsigned int oper_speed;
 };
 
 /* HCI_UART proto flag bits */
@@ -99,7 +102,11 @@ int hci_uart_register_proto(const struct hci_uart_proto *p);
 int hci_uart_unregister_proto(const struct hci_uart_proto *p);
 int hci_uart_tx_wakeup(struct hci_uart *hu);
 int hci_uart_init_ready(struct hci_uart *hu);
+void hci_uart_init_tty(struct hci_uart *hu);
 void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed);
+void hci_uart_set_flow_control(struct hci_uart *hu, bool enable);
+void hci_uart_set_speeds(struct hci_uart *hu, unsigned int init_speed,
+			 unsigned int oper_speed);
 
 #ifdef CONFIG_BT_HCIUART_H4
 int h4_init(void);
-- 
1.9.1