TTY/Serial driver fixes for 4.16-rc6

Here are some small TTY core and Serial driver fixes for 4.16-rc6.
 
 They resolve some newly reported bugs, as well as some very old ones,
 which is always nice to see.  There is also a new device id added in
 here for good measure.
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-4.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver fixes from Greg KH:
 "Here are some small tty core and serial driver fixes for 4.16-rc6.

  They resolve some newly reported bugs, as well as some very old ones,
  which is always nice to see. There is also a new device id added in
  here for good measure.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-4.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: imx: fix bogus dev_err
  serial: sh-sci: prevent lockup on full TTY buffers
  serial: 8250_pci: Add Brainboxes UC-260 4 port serial device
  earlycon: add reg-offset to physical address before mapping
  serial: core: mark port as initialized in autoconfig
  serial: 8250_pci: Don't fail on multiport card class
  tty/serial: atmel: add new version check for usart
  tty: make n_tty_read() always abort if hangup is in progress

drivers/tty/n_tty.c

@@ -2180,6 +2180,12 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 				}
 				if (tty_hung_up_p(file))
 					break;
+				/*
+				 * Abort readers for ttys which never actually
+				 * get hung up.  See __tty_hangup().
+				 */
+				if (test_bit(TTY_HUPPING, &tty->flags))
+					break;
 				if (!timeout)
 					break;
 				if (file->f_flags & O_NONBLOCK) {

drivers/tty/serial/8250/8250_pci.c

@@ -3387,11 +3387,9 @@ static int serial_pci_is_class_communication(struct pci_dev *dev)
 	/*
 	 * If it is not a communications device or the programming
 	 * interface is greater than 6, give up.
-	 *
-	 * (Should we try to make guesses for multiport serial devices
-	 * later?)
 	 */
 	if ((((dev->class >> 8) != PCI_CLASS_COMMUNICATION_SERIAL) &&
+	     ((dev->class >> 8) != PCI_CLASS_COMMUNICATION_MULTISERIAL) &&
 	     ((dev->class >> 8) != PCI_CLASS_COMMUNICATION_MODEM)) ||
 	    (dev->class & 0xff) > 6)
 		return -ENODEV;
@@ -3428,6 +3426,12 @@ serial_pci_guess_board(struct pci_dev *dev, struct pciserial_board *board)
 {
 	int num_iomem, num_port, first_port = -1, i;
 
+	/*
+	 * Should we try to make guesses for multiport serial devices later?
+	 */
+	if ((dev->class >> 8) == PCI_CLASS_COMMUNICATION_MULTISERIAL)
+		return -ENODEV;
+
 	num_iomem = num_port = 0;
 	for (i = 0; i < PCI_NUM_BAR_RESOURCES; i++) {
 		if (pci_resource_flags(dev, i) & IORESOURCE_IO) {
@@ -4698,6 +4702,17 @@ static const struct pci_device_id serial_pci_tbl[] = {
 	{	PCI_VENDOR_ID_INTASHIELD, PCI_DEVICE_ID_INTASHIELD_IS400,
 		PCI_ANY_ID, PCI_ANY_ID, 0, 0,    /* 135a.0dc0 */
 		pbn_b2_4_115200 },
+	/*
+	 * BrainBoxes UC-260
+	 */
+	{	PCI_VENDOR_ID_INTASHIELD, 0x0D21,
+		PCI_ANY_ID, PCI_ANY_ID,
+		PCI_CLASS_COMMUNICATION_MULTISERIAL << 8, 0xffff00,
+		pbn_b2_4_115200 },
+	{	PCI_VENDOR_ID_INTASHIELD, 0x0E34,
+		PCI_ANY_ID, PCI_ANY_ID,
+		 PCI_CLASS_COMMUNICATION_MULTISERIAL << 8, 0xffff00,
+		pbn_b2_4_115200 },
 	/*
 	 * Perle PCI-RAS cards
 	 */

drivers/tty/serial/atmel_serial.c

@@ -1734,6 +1734,7 @@ static void atmel_get_ip_name(struct uart_port *port)
 		switch (version) {
 		case 0x302:
 		case 0x10213:
+		case 0x10302:
 			dev_dbg(port->dev, "This version is usart\n");
 			atmel_port->has_frac_baudrate = true;
 			atmel_port->has_hw_timer = true;

drivers/tty/serial/earlycon.c

@@ -245,11 +245,12 @@ int __init of_setup_earlycon(const struct earlycon_id *match,
 	}
 	port->mapbase = addr;
 	port->uartclk = BASE_BAUD * 16;
-	port->membase = earlycon_map(port->mapbase, SZ_4K);
 
 	val = of_get_flat_dt_prop(node, "reg-offset", NULL);
 	if (val)
 		port->mapbase += be32_to_cpu(*val);
+	port->membase = earlycon_map(port->mapbase, SZ_4K);
+
 	val = of_get_flat_dt_prop(node, "reg-shift", NULL);
 	if (val)
 		port->regshift = be32_to_cpu(*val);

drivers/tty/serial/imx.c

@@ -2093,7 +2093,7 @@ static int serial_imx_probe(struct platform_device *pdev)
 	uart_get_rs485_mode(&pdev->dev, &sport->port.rs485);
 
 	if (sport->port.rs485.flags & SER_RS485_ENABLED &&
-	    (!sport->have_rtscts || !sport->have_rtsgpio))
+	    (!sport->have_rtscts && !sport->have_rtsgpio))
 		dev_err(&pdev->dev, "no RTS control, disabling rs485\n");
 
 	imx_rs485_config(&sport->port, &sport->port.rs485);

drivers/tty/serial/serial_core.c

@@ -1144,6 +1144,8 @@ static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state)
 		uport->ops->config_port(uport, flags);
 
 		ret = uart_startup(tty, state, 1);
+		if (ret == 0)
+			tty_port_set_initialized(port, true);
 		if (ret > 0)
 			ret = 0;
 	}

drivers/tty/serial/sh-sci.c

@@ -885,6 +885,8 @@ static void sci_receive_chars(struct uart_port *port)
 		/* Tell the rest of the system the news. New characters! */
 		tty_flip_buffer_push(tport);
 	} else {
+		/* TTY buffers full; read from RX reg to prevent lockup */
+		serial_port_in(port, SCxRDR);
 		serial_port_in(port, SCxSR); /* dummy read */
 		sci_clear_SCxSR(port, SCxSR_RDxF_CLEAR(port));
 	}

drivers/tty/tty_io.c

@@ -586,6 +586,14 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session)
 		return;
 	}
 
+	/*
+	 * Some console devices aren't actually hung up for technical and
+	 * historical reasons, which can lead to indefinite interruptible
+	 * sleep in n_tty_read().  The following explicitly tells
+	 * n_tty_read() to abort readers.
+	 */
+	set_bit(TTY_HUPPING, &tty->flags);
+
 	/* inuse_filps is protected by the single tty lock,
 	   this really needs to change if we want to flush the
 	   workqueue with the lock held */
@@ -640,6 +648,7 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session)
 	 * from the ldisc side, which is now guaranteed.
 	 */
 	set_bit(TTY_HUPPED, &tty->flags);
+	clear_bit(TTY_HUPPING, &tty->flags);
 	tty_unlock(tty);
 
 	if (f)

include/linux/tty.h

@@ -364,6 +364,7 @@ struct tty_file_private {
 #define TTY_PTY_LOCK 		16	/* pty private */
 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
 #define TTY_HUPPED 		18	/* Post driver->hangup() */
+#define TTY_HUPPING		19	/* Hangup in progress */
 #define TTY_LDISC_HALTED	22	/* Line discipline is halted */
 
 /* Values for tty->flow_change */