Commit 06f79d57 authored by Johan Hovold's avatar Johan Hovold
Browse files

USB: serial: xr: reset FIFOs on open 



Reset the transmit and receive FIFOs before enabling the UARTs as part
of open() in order to flush any stale data.

Note that the XR21V141X needs a type-specific implementation due to its
UART Manager registers.

Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent 6da99f9d

drivers/usb/serial/xr_serial.c

+51 −0
Original line number Diff line number Diff line
@@ -95,10 +95,13 @@ struct xr_txrx_clk_mask { 
#define XR_GPIO_MODE_TX_TOGGLE		0x100

#define XR_GPIO_MODE_RX_TOGGLE		0x200



#define XR_FIFO_RESET			0x1



#define XR_CUSTOM_DRIVER_ACTIVE		0x1



static int xr21v141x_uart_enable(struct usb_serial_port *port);

static int xr21v141x_uart_disable(struct usb_serial_port *port);

static int xr21v141x_fifo_reset(struct usb_serial_port *port);

static void xr21v141x_set_line_settings(struct tty_struct *tty,

		struct usb_serial_port *port, struct ktermios *old_termios);
@@ -118,6 +121,8 @@ struct xr_type { 
	u16 gpio_set;

	u16 gpio_clear;

	u16 gpio_status;

	u16 tx_fifo_reset;

	u16 rx_fifo_reset;

	u16 custom_driver;



	bool have_5_6_bit_mode;
@@ -125,6 +130,7 @@ struct xr_type { 


	int (*enable)(struct usb_serial_port *port);

	int (*disable)(struct usb_serial_port *port);

	int (*fifo_reset)(struct usb_serial_port *port);

	void (*set_line_settings)(struct tty_struct *tty,

			struct usb_serial_port *port,

			struct ktermios *old_termios);
@@ -158,6 +164,7 @@ static const struct xr_type xr_types[] = { 


		.enable			= xr21v141x_uart_enable,

		.disable		= xr21v141x_uart_disable,

		.fifo_reset		= xr21v141x_fifo_reset,

		.set_line_settings	= xr21v141x_set_line_settings,

	},

	[XR21B142X] = {
@@ -176,6 +183,8 @@ static const struct xr_type xr_types[] = { 
		.gpio_set	= 0x0e,

		.gpio_clear	= 0x0f,

		.gpio_status	= 0x10,

		.tx_fifo_reset	= 0x40,

		.rx_fifo_reset	= 0x43,

		.custom_driver	= 0x60,



		.have_5_6_bit_mode	= true,
@@ -197,6 +206,8 @@ static const struct xr_type xr_types[] = { 
		.gpio_set	= 0xc0e,

		.gpio_clear	= 0xc0f,

		.gpio_status	= 0xc10,

		.tx_fifo_reset	= 0xc80,

		.rx_fifo_reset	= 0xcc0,

		.custom_driver	= 0x20d,

	},

	[XR2280X] = {
@@ -215,6 +226,8 @@ static const struct xr_type xr_types[] = { 
		.gpio_set	= 0x4e,

		.gpio_clear	= 0x4f,

		.gpio_status	= 0x50,

		.tx_fifo_reset	= 0x60,

		.rx_fifo_reset	= 0x63,

		.custom_driver	= 0x81,

	},

};
@@ -384,6 +397,40 @@ static int xr_uart_disable(struct usb_serial_port *port) 
	return __xr_uart_disable(port);

}



static int xr21v141x_fifo_reset(struct usb_serial_port *port)

{

	int ret;



	ret = xr_set_reg_um(port, XR21V141X_UM_TX_FIFO_RESET, XR_FIFO_RESET);

	if (ret)

		return ret;



	ret = xr_set_reg_um(port, XR21V141X_UM_RX_FIFO_RESET, XR_FIFO_RESET);

	if (ret)

		return ret;



	return 0;

}



static int xr_fifo_reset(struct usb_serial_port *port)

{

	struct xr_data *data = usb_get_serial_port_data(port);

	int ret;



	if (data->type->fifo_reset)

		return data->type->fifo_reset(port);



	ret = xr_set_reg_uart(port, data->type->tx_fifo_reset, XR_FIFO_RESET);

	if (ret)

		return ret;



	ret = xr_set_reg_uart(port, data->type->rx_fifo_reset, XR_FIFO_RESET);

	if (ret)

		return ret;



	return 0;

}



static int xr_tiocmget(struct tty_struct *tty)

{

	struct usb_serial_port *port = tty->driver_data;
@@ -781,6 +828,10 @@ static int xr_open(struct tty_struct *tty, struct usb_serial_port *port) 
{

	int ret;



	ret = xr_fifo_reset(port);

	if (ret)

		return ret;



	ret = xr_uart_enable(port);

	if (ret) {

		dev_err(&port->dev, "Failed to enable UART\n");