Commit ed921771 authored by Johan Hovold's avatar Johan Hovold
Browse files

USB: serial: cp210x: refactor flow-control handling 



Add a helper function to be used to configure flow control.

The flow-control code was the last caller that relied on the
memset-on-failure behaviour of cp210x_read_reg_block(), which we can now
drop in favour of bailing out on errors when retrieving the flow-control
settings.

This should also simplify adding support for software flow control.

Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent b339628e

drivers/usb/serial/cp210x.c

+47 −50
Original line number Diff line number Diff line
@@ -555,14 +555,8 @@ static int cp210x_read_reg_block(struct usb_serial_port *port, u8 req, 
	int result;



	dmabuf = kmalloc(bufsize, GFP_KERNEL);

	if (!dmabuf) {

		/*

		 * FIXME Some callers don't bother to check for error,

		 * at least give them consistent junk until they are fixed

		 */

		memset(buf, 0, bufsize);

	if (!dmabuf)

		return -ENOMEM;

	}



	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),

			req, REQTYPE_INTERFACE_TO_HOST, 0,
@@ -576,12 +570,6 @@ static int cp210x_read_reg_block(struct usb_serial_port *port, u8 req, 
				req, bufsize, result);

		if (result >= 0)

			result = -EIO;



		/*

		 * FIXME Some callers don't bother to check for error,

		 * at least give them consistent junk until they are fixed

		 */

		memset(buf, 0, bufsize);

	}



	kfree(dmabuf);
@@ -1095,11 +1083,55 @@ static bool cp210x_termios_change(const struct ktermios *a, const struct ktermio 
	return tty_termios_hw_change(a, b) || iflag_change;

}



static void cp210x_set_flow_control(struct tty_struct *tty,

		struct usb_serial_port *port, struct ktermios *old_termios)

{

	struct cp210x_flow_ctl flow_ctl;

	u32 flow_repl;

	u32 ctl_hs;

	int ret;



	if (old_termios && C_CRTSCTS(tty) == (old_termios->c_cflag & CRTSCTS))

		return;



	ret = cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,

			sizeof(flow_ctl));

	if (ret)

		return;



	ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake);

	flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace);



	ctl_hs &= ~CP210X_SERIAL_DSR_HANDSHAKE;

	ctl_hs &= ~CP210X_SERIAL_DCD_HANDSHAKE;

	ctl_hs &= ~CP210X_SERIAL_DSR_SENSITIVITY;

	ctl_hs &= ~CP210X_SERIAL_DTR_MASK;

	ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_ACTIVE);



	if (C_CRTSCTS(tty)) {

		ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;

		flow_repl &= ~CP210X_SERIAL_RTS_MASK;

		flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_FLOW_CTL);

	} else {

		ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;

		flow_repl &= ~CP210X_SERIAL_RTS_MASK;

		flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE);

	}



	dev_dbg(&port->dev, "%s - ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n",

			__func__, ctl_hs, flow_repl);



	flow_ctl.ulControlHandshake = cpu_to_le32(ctl_hs);

	flow_ctl.ulFlowReplace = cpu_to_le32(flow_repl);



	cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,

			sizeof(flow_ctl));

}



static void cp210x_set_termios(struct tty_struct *tty,

		struct usb_serial_port *port, struct ktermios *old_termios)

{

	struct cp210x_serial_private *priv = usb_get_serial_data(port->serial);

	struct device *dev = &port->dev;

	u16 bits;

	int ret;
@@ -1156,42 +1188,7 @@ static void cp210x_set_termios(struct tty_struct *tty, 
	if (ret)

		dev_err(&port->dev, "failed to set line control: %d\n", ret);



	if (!old_termios || C_CRTSCTS(tty) != (old_termios->c_cflag & CRTSCTS)) {

		struct cp210x_flow_ctl flow_ctl;

		u32 ctl_hs;

		u32 flow_repl;



		cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,

				sizeof(flow_ctl));

		ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake);

		flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace);



		ctl_hs &= ~CP210X_SERIAL_DSR_HANDSHAKE;

		ctl_hs &= ~CP210X_SERIAL_DCD_HANDSHAKE;

		ctl_hs &= ~CP210X_SERIAL_DSR_SENSITIVITY;

		ctl_hs &= ~CP210X_SERIAL_DTR_MASK;

		ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_ACTIVE);

		if (C_CRTSCTS(tty)) {

			ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;



			flow_repl &= ~CP210X_SERIAL_RTS_MASK;

			flow_repl |= CP210X_SERIAL_RTS_SHIFT(

					CP210X_SERIAL_RTS_FLOW_CTL);

		} else {

			ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;



			flow_repl &= ~CP210X_SERIAL_RTS_MASK;

			flow_repl |= CP210X_SERIAL_RTS_SHIFT(

					CP210X_SERIAL_RTS_ACTIVE);

		}



		dev_dbg(dev, "%s - ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n",

				__func__, ctl_hs, flow_repl);

		flow_ctl.ulControlHandshake = cpu_to_le32(ctl_hs);

		flow_ctl.ulFlowReplace = cpu_to_le32(flow_repl);

		cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,

				sizeof(flow_ctl));

	}

	cp210x_set_flow_control(tty, port, old_termios);



	/*

	 * Enable event-insertion mode only if input parity checking is

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