Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 777 insertions, 0 deletions

diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c
new file mode 100644
index 000000000..d3852feb8
--- /dev/null
+++ b/drivers/usb/serial/mct_u232.c
@@ -0,0 +1,777 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * MCT (Magic Control Technology Corp.) USB RS232 Converter Driver
+ *
+ *   Copyright (C) 2000 Wolfgang Grandegger (wolfgang@ces.ch)
+ *
+ * This program is largely derived from the Belkin USB Serial Adapter Driver
+ * (see belkin_sa.[ch]). All of the information about the device was acquired
+ * by using SniffUSB on Windows98. For technical details see mct_u232.h.
+ *
+ * William G. Greathouse and Greg Kroah-Hartman provided great help on how to
+ * do the reverse engineering and how to write a USB serial device driver.
+ *
+ * TO BE DONE, TO BE CHECKED:
+ *   DTR/RTS signal handling may be incomplete or incorrect. I have mainly
+ *   implemented what I have seen with SniffUSB or found in belkin_sa.c.
+ *   For further TODOs check also belkin_sa.c.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <asm/unaligned.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <linux/serial.h>
+#include "mct_u232.h"
+
+#define DRIVER_AUTHOR "Wolfgang Grandegger <wolfgang@ces.ch>"
+#define DRIVER_DESC "Magic Control Technology USB-RS232 converter driver"
+
+/*
+ * Function prototypes
+ */
+static int  mct_u232_port_probe(struct usb_serial_port *port);
+static void mct_u232_port_remove(struct usb_serial_port *remove);
+static int  mct_u232_open(struct tty_struct *tty, struct usb_serial_port *port);
+static void mct_u232_close(struct usb_serial_port *port);
+static void mct_u232_dtr_rts(struct usb_serial_port *port, int on);
+static void mct_u232_read_int_callback(struct urb *urb);
+static void mct_u232_set_termios(struct tty_struct *tty,
+				 struct usb_serial_port *port,
+				 const struct ktermios *old_termios);
+static void mct_u232_break_ctl(struct tty_struct *tty, int break_state);
+static int  mct_u232_tiocmget(struct tty_struct *tty);
+static int  mct_u232_tiocmset(struct tty_struct *tty,
+			unsigned int set, unsigned int clear);
+static void mct_u232_throttle(struct tty_struct *tty);
+static void mct_u232_unthrottle(struct tty_struct *tty);
+
+
+/*
+ * All of the device info needed for the MCT USB-RS232 converter.
+ */
+static const struct usb_device_id id_table[] = {
+	{ USB_DEVICE(MCT_U232_VID, MCT_U232_PID) },
+	{ USB_DEVICE(MCT_U232_VID, MCT_U232_SITECOM_PID) },
+	{ USB_DEVICE(MCT_U232_VID, MCT_U232_DU_H3SP_PID) },
+	{ USB_DEVICE(MCT_U232_BELKIN_F5U109_VID, MCT_U232_BELKIN_F5U109_PID) },
+	{ }		/* Terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+static struct usb_serial_driver mct_u232_device = {
+	.driver = {
+		.owner =	THIS_MODULE,
+		.name =		"mct_u232",
+	},
+	.description =	     "MCT U232",
+	.id_table =	     id_table,
+	.num_ports =	     1,
+	.open =		     mct_u232_open,
+	.close =	     mct_u232_close,
+	.dtr_rts =	     mct_u232_dtr_rts,
+	.throttle =	     mct_u232_throttle,
+	.unthrottle =	     mct_u232_unthrottle,
+	.read_int_callback = mct_u232_read_int_callback,
+	.set_termios =	     mct_u232_set_termios,
+	.break_ctl =	     mct_u232_break_ctl,
+	.tiocmget =	     mct_u232_tiocmget,
+	.tiocmset =	     mct_u232_tiocmset,
+	.tiocmiwait =        usb_serial_generic_tiocmiwait,
+	.port_probe =        mct_u232_port_probe,
+	.port_remove =       mct_u232_port_remove,
+	.get_icount =        usb_serial_generic_get_icount,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+	&mct_u232_device, NULL
+};
+
+struct mct_u232_private {
+	struct urb *read_urb;
+	spinlock_t lock;
+	unsigned int	     control_state; /* Modem Line Setting (TIOCM) */
+	unsigned char        last_lcr;      /* Line Control Register */
+	unsigned char	     last_lsr;      /* Line Status Register */
+	unsigned char	     last_msr;      /* Modem Status Register */
+	unsigned int	     rx_flags;      /* Throttling flags */
+};
+
+#define THROTTLED		0x01
+
+/*
+ * Handle vendor specific USB requests
+ */
+
+#define WDR_TIMEOUT 5000 /* default urb timeout */
+
+/*
+ * Later day 2.6.0-test kernels have new baud rates like B230400 which
+ * we do not know how to support. We ignore them for the moment.
+ */
+static int mct_u232_calculate_baud_rate(struct usb_serial *serial,
+					speed_t value, speed_t *result)
+{
+	*result = value;
+
+	if (le16_to_cpu(serial->dev->descriptor.idProduct) == MCT_U232_SITECOM_PID
+		|| le16_to_cpu(serial->dev->descriptor.idProduct) == MCT_U232_BELKIN_F5U109_PID) {
+		switch (value) {
+		case 300:
+			return 0x01;
+		case 600:
+			return 0x02; /* this one not tested */
+		case 1200:
+			return 0x03;
+		case 2400:
+			return 0x04;
+		case 4800:
+			return 0x06;
+		case 9600:
+			return 0x08;
+		case 19200:
+			return 0x09;
+		case 38400:
+			return 0x0a;
+		case 57600:
+			return 0x0b;
+		case 115200:
+			return 0x0c;
+		default:
+			*result = 9600;
+			return 0x08;
+		}
+	} else {
+		/* FIXME: Can we use any divider - should we do
+		   divider = 115200/value;
+		   real baud = 115200/divider */
+		switch (value) {
+		case 300: break;
+		case 600: break;
+		case 1200: break;
+		case 2400: break;
+		case 4800: break;
+		case 9600: break;
+		case 19200: break;
+		case 38400: break;
+		case 57600: break;
+		case 115200: break;
+		default:
+			value = 9600;
+			*result = 9600;
+		}
+		return 115200/value;
+	}
+}
+
+static int mct_u232_set_baud_rate(struct tty_struct *tty,
+	struct usb_serial *serial, struct usb_serial_port *port, speed_t value)
+{
+	unsigned int divisor;
+	int rc;
+	unsigned char *buf;
+	unsigned char cts_enable_byte = 0;
+	speed_t speed;
+
+	buf = kmalloc(MCT_U232_MAX_SIZE, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	divisor = mct_u232_calculate_baud_rate(serial, value, &speed);
+	put_unaligned_le32(divisor, buf);
+	rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
+				MCT_U232_SET_BAUD_RATE_REQUEST,
+				MCT_U232_SET_REQUEST_TYPE,
+				0, 0, buf, MCT_U232_SET_BAUD_RATE_SIZE,
+				WDR_TIMEOUT);
+	if (rc < 0)	/*FIXME: What value speed results */
+		dev_err(&port->dev, "Set BAUD RATE %d failed (error = %d)\n",
+			value, rc);
+	else
+		tty_encode_baud_rate(tty, speed, speed);
+	dev_dbg(&port->dev, "set_baud_rate: value: 0x%x, divisor: 0x%x\n", value, divisor);
+
+	/* Mimic the MCT-supplied Windows driver (version 1.21P.0104), which
+	   always sends two extra USB 'device request' messages after the
+	   'baud rate change' message.  The actual functionality of the
+	   request codes in these messages is not fully understood but these
+	   particular codes are never seen in any operation besides a baud
+	   rate change.  Both of these messages send a single byte of data.
+	   In the first message, the value of this byte is always zero.
+
+	   The second message has been determined experimentally to control
+	   whether data will be transmitted to a device which is not asserting
+	   the 'CTS' signal.  If the second message's data byte is zero, data
+	   will be transmitted even if 'CTS' is not asserted (i.e. no hardware
+	   flow control).  if the second message's data byte is nonzero (a
+	   value of 1 is used by this driver), data will not be transmitted to
+	   a device which is not asserting 'CTS'.
+	*/
+
+	buf[0] = 0;
+	rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
+				MCT_U232_SET_UNKNOWN1_REQUEST,
+				MCT_U232_SET_REQUEST_TYPE,
+				0, 0, buf, MCT_U232_SET_UNKNOWN1_SIZE,
+				WDR_TIMEOUT);
+	if (rc < 0)
+		dev_err(&port->dev, "Sending USB device request code %d "
+			"failed (error = %d)\n", MCT_U232_SET_UNKNOWN1_REQUEST,
+			rc);
+
+	if (port && C_CRTSCTS(tty))
+	   cts_enable_byte = 1;
+
+	dev_dbg(&port->dev, "set_baud_rate: send second control message, data = %02X\n",
+		cts_enable_byte);
+	buf[0] = cts_enable_byte;
+	rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
+			MCT_U232_SET_CTS_REQUEST,
+			MCT_U232_SET_REQUEST_TYPE,
+			0, 0, buf, MCT_U232_SET_CTS_SIZE,
+			WDR_TIMEOUT);
+	if (rc < 0)
+		dev_err(&port->dev, "Sending USB device request code %d "
+			"failed (error = %d)\n", MCT_U232_SET_CTS_REQUEST, rc);
+
+	kfree(buf);
+	return rc;
+} /* mct_u232_set_baud_rate */
+
+static int mct_u232_set_line_ctrl(struct usb_serial_port *port,
+				  unsigned char lcr)
+{
+	int rc;
+	unsigned char *buf;
+
+	buf = kmalloc(MCT_U232_MAX_SIZE, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	buf[0] = lcr;
+	rc = usb_control_msg(port->serial->dev, usb_sndctrlpipe(port->serial->dev, 0),
+			MCT_U232_SET_LINE_CTRL_REQUEST,
+			MCT_U232_SET_REQUEST_TYPE,
+			0, 0, buf, MCT_U232_SET_LINE_CTRL_SIZE,
+			WDR_TIMEOUT);
+	if (rc < 0)
+		dev_err(&port->dev, "Set LINE CTRL 0x%x failed (error = %d)\n", lcr, rc);
+	dev_dbg(&port->dev, "set_line_ctrl: 0x%x\n", lcr);
+	kfree(buf);
+	return rc;
+} /* mct_u232_set_line_ctrl */
+
+static int mct_u232_set_modem_ctrl(struct usb_serial_port *port,
+				   unsigned int control_state)
+{
+	int rc;
+	unsigned char mcr;
+	unsigned char *buf;
+
+	buf = kmalloc(MCT_U232_MAX_SIZE, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	mcr = MCT_U232_MCR_NONE;
+	if (control_state & TIOCM_DTR)
+		mcr |= MCT_U232_MCR_DTR;
+	if (control_state & TIOCM_RTS)
+		mcr |= MCT_U232_MCR_RTS;
+
+	buf[0] = mcr;
+	rc = usb_control_msg(port->serial->dev, usb_sndctrlpipe(port->serial->dev, 0),
+			MCT_U232_SET_MODEM_CTRL_REQUEST,
+			MCT_U232_SET_REQUEST_TYPE,
+			0, 0, buf, MCT_U232_SET_MODEM_CTRL_SIZE,
+			WDR_TIMEOUT);
+	kfree(buf);
+
+	dev_dbg(&port->dev, "set_modem_ctrl: state=0x%x ==> mcr=0x%x\n", control_state, mcr);
+
+	if (rc < 0) {
+		dev_err(&port->dev, "Set MODEM CTRL 0x%x failed (error = %d)\n", mcr, rc);
+		return rc;
+	}
+	return 0;
+} /* mct_u232_set_modem_ctrl */
+
+static int mct_u232_get_modem_stat(struct usb_serial_port *port,
+				   unsigned char *msr)
+{
+	int rc;
+	unsigned char *buf;
+
+	buf = kmalloc(MCT_U232_MAX_SIZE, GFP_KERNEL);
+	if (buf == NULL) {
+		*msr = 0;
+		return -ENOMEM;
+	}
+	rc = usb_control_msg(port->serial->dev, usb_rcvctrlpipe(port->serial->dev, 0),
+			MCT_U232_GET_MODEM_STAT_REQUEST,
+			MCT_U232_GET_REQUEST_TYPE,
+			0, 0, buf, MCT_U232_GET_MODEM_STAT_SIZE,
+			WDR_TIMEOUT);
+	if (rc < MCT_U232_GET_MODEM_STAT_SIZE) {
+		dev_err(&port->dev, "Get MODEM STATus failed (error = %d)\n", rc);
+
+		if (rc >= 0)
+			rc = -EIO;
+
+		*msr = 0;
+	} else {
+		*msr = buf[0];
+	}
+	dev_dbg(&port->dev, "get_modem_stat: 0x%x\n", *msr);
+	kfree(buf);
+	return rc;
+} /* mct_u232_get_modem_stat */
+
+static void mct_u232_msr_to_icount(struct async_icount *icount,
+						unsigned char msr)
+{
+	/* Translate Control Line states */
+	if (msr & MCT_U232_MSR_DDSR)
+		icount->dsr++;
+	if (msr & MCT_U232_MSR_DCTS)
+		icount->cts++;
+	if (msr & MCT_U232_MSR_DRI)
+		icount->rng++;
+	if (msr & MCT_U232_MSR_DCD)
+		icount->dcd++;
+} /* mct_u232_msr_to_icount */
+
+static void mct_u232_msr_to_state(struct usb_serial_port *port,
+				  unsigned int *control_state, unsigned char msr)
+{
+	/* Translate Control Line states */
+	if (msr & MCT_U232_MSR_DSR)
+		*control_state |=  TIOCM_DSR;
+	else
+		*control_state &= ~TIOCM_DSR;
+	if (msr & MCT_U232_MSR_CTS)
+		*control_state |=  TIOCM_CTS;
+	else
+		*control_state &= ~TIOCM_CTS;
+	if (msr & MCT_U232_MSR_RI)
+		*control_state |=  TIOCM_RI;
+	else
+		*control_state &= ~TIOCM_RI;
+	if (msr & MCT_U232_MSR_CD)
+		*control_state |=  TIOCM_CD;
+	else
+		*control_state &= ~TIOCM_CD;
+	dev_dbg(&port->dev, "msr_to_state: msr=0x%x ==> state=0x%x\n", msr, *control_state);
+} /* mct_u232_msr_to_state */
+
+/*
+ * Driver's tty interface functions
+ */
+
+static int mct_u232_port_probe(struct usb_serial_port *port)
+{
+	struct usb_serial *serial = port->serial;
+	struct mct_u232_private *priv;
+
+	/* check first to simplify error handling */
+	if (!serial->port[1] || !serial->port[1]->interrupt_in_urb) {
+		dev_err(&port->dev, "expected endpoint missing\n");
+		return -ENODEV;
+	}
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	/* Use second interrupt-in endpoint for reading. */
+	priv->read_urb = serial->port[1]->interrupt_in_urb;
+	priv->read_urb->context = port;
+
+	spin_lock_init(&priv->lock);
+
+	usb_set_serial_port_data(port, priv);
+
+	return 0;
+}
+
+static void mct_u232_port_remove(struct usb_serial_port *port)
+{
+	struct mct_u232_private *priv;
+
+	priv = usb_get_serial_port_data(port);
+	kfree(priv);
+}
+
+static int  mct_u232_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+	struct usb_serial *serial = port->serial;
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+	int retval = 0;
+	unsigned int control_state;
+	unsigned long flags;
+	unsigned char last_lcr;
+	unsigned char last_msr;
+
+	/* Compensate for a hardware bug: although the Sitecom U232-P25
+	 * device reports a maximum output packet size of 32 bytes,
+	 * it seems to be able to accept only 16 bytes (and that's what
+	 * SniffUSB says too...)
+	 */
+	if (le16_to_cpu(serial->dev->descriptor.idProduct)
+						== MCT_U232_SITECOM_PID)
+		port->bulk_out_size = 16;
+
+	/* Do a defined restart: the normal serial device seems to
+	 * always turn on DTR and RTS here, so do the same. I'm not
+	 * sure if this is really necessary. But it should not harm
+	 * either.
+	 */
+	spin_lock_irqsave(&priv->lock, flags);
+	if (tty && C_BAUD(tty))
+		priv->control_state = TIOCM_DTR | TIOCM_RTS;
+	else
+		priv->control_state = 0;
+
+	priv->last_lcr = (MCT_U232_DATA_BITS_8 |
+			  MCT_U232_PARITY_NONE |
+			  MCT_U232_STOP_BITS_1);
+	control_state = priv->control_state;
+	last_lcr = priv->last_lcr;
+	spin_unlock_irqrestore(&priv->lock, flags);
+	mct_u232_set_modem_ctrl(port, control_state);
+	mct_u232_set_line_ctrl(port, last_lcr);
+
+	/* Read modem status and update control state */
+	mct_u232_get_modem_stat(port, &last_msr);
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->last_msr = last_msr;
+	mct_u232_msr_to_state(port, &priv->control_state, priv->last_msr);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	retval = usb_submit_urb(priv->read_urb, GFP_KERNEL);
+	if (retval) {
+		dev_err(&port->dev,
+			"usb_submit_urb(read) failed pipe 0x%x err %d\n",
+			port->read_urb->pipe, retval);
+		goto error;
+	}
+
+	retval = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
+	if (retval) {
+		usb_kill_urb(priv->read_urb);
+		dev_err(&port->dev,
+			"usb_submit_urb(read int) failed pipe 0x%x err %d",
+			port->interrupt_in_urb->pipe, retval);
+		goto error;
+	}
+	return 0;
+
+error:
+	return retval;
+} /* mct_u232_open */
+
+static void mct_u232_dtr_rts(struct usb_serial_port *port, int on)
+{
+	unsigned int control_state;
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+
+	spin_lock_irq(&priv->lock);
+	if (on)
+		priv->control_state |= TIOCM_DTR | TIOCM_RTS;
+	else
+		priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
+	control_state = priv->control_state;
+	spin_unlock_irq(&priv->lock);
+
+	mct_u232_set_modem_ctrl(port, control_state);
+}
+
+static void mct_u232_close(struct usb_serial_port *port)
+{
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+
+	usb_kill_urb(priv->read_urb);
+	usb_kill_urb(port->interrupt_in_urb);
+
+	usb_serial_generic_close(port);
+} /* mct_u232_close */
+
+
+static void mct_u232_read_int_callback(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+	unsigned char *data = urb->transfer_buffer;
+	int retval;
+	int status = urb->status;
+	unsigned long flags;
+
+	switch (status) {
+	case 0:
+		/* success */
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		/* this urb is terminated, clean up */
+		dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
+			__func__, status);
+		return;
+	default:
+		dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
+			__func__, status);
+		goto exit;
+	}
+
+	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
+
+	/*
+	 * Work-a-round: handle the 'usual' bulk-in pipe here
+	 */
+	if (urb->transfer_buffer_length > 2) {
+		if (urb->actual_length) {
+			tty_insert_flip_string(&port->port, data,
+					urb->actual_length);
+			tty_flip_buffer_push(&port->port);
+		}
+		goto exit;
+	}
+
+	/*
+	 * The interrupt-in pipe signals exceptional conditions (modem line
+	 * signal changes and errors). data[0] holds MSR, data[1] holds LSR.
+	 */
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->last_msr = data[MCT_U232_MSR_INDEX];
+
+	/* Record Control Line states */
+	mct_u232_msr_to_state(port, &priv->control_state, priv->last_msr);
+
+	mct_u232_msr_to_icount(&port->icount, priv->last_msr);
+
+#if 0
+	/* Not yet handled. See belkin_sa.c for further information */
+	/* Now to report any errors */
+	priv->last_lsr = data[MCT_U232_LSR_INDEX];
+	/*
+	 * fill in the flip buffer here, but I do not know the relation
+	 * to the current/next receive buffer or characters.  I need
+	 * to look in to this before committing any code.
+	 */
+	if (priv->last_lsr & MCT_U232_LSR_ERR) {
+		tty = tty_port_tty_get(&port->port);
+		/* Overrun Error */
+		if (priv->last_lsr & MCT_U232_LSR_OE) {
+		}
+		/* Parity Error */
+		if (priv->last_lsr & MCT_U232_LSR_PE) {
+		}
+		/* Framing Error */
+		if (priv->last_lsr & MCT_U232_LSR_FE) {
+		}
+		/* Break Indicator */
+		if (priv->last_lsr & MCT_U232_LSR_BI) {
+		}
+		tty_kref_put(tty);
+	}
+#endif
+	wake_up_interruptible(&port->port.delta_msr_wait);
+	spin_unlock_irqrestore(&priv->lock, flags);
+exit:
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval)
+		dev_err(&port->dev,
+			"%s - usb_submit_urb failed with result %d\n",
+			__func__, retval);
+} /* mct_u232_read_int_callback */
+
+static void mct_u232_set_termios(struct tty_struct *tty,
+				 struct usb_serial_port *port,
+				 const struct ktermios *old_termios)
+{
+	struct usb_serial *serial = port->serial;
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+	struct ktermios *termios = &tty->termios;
+	unsigned int cflag = termios->c_cflag;
+	unsigned int old_cflag = old_termios->c_cflag;
+	unsigned long flags;
+	unsigned int control_state;
+	unsigned char last_lcr;
+
+	/* get a local copy of the current port settings */
+	spin_lock_irqsave(&priv->lock, flags);
+	control_state = priv->control_state;
+	spin_unlock_irqrestore(&priv->lock, flags);
+	last_lcr = 0;
+
+	/*
+	 * Update baud rate.
+	 * Do not attempt to cache old rates and skip settings,
+	 * disconnects screw such tricks up completely.
+	 * Premature optimization is the root of all evil.
+	 */
+
+	/* reassert DTR and RTS on transition from B0 */
+	if ((old_cflag & CBAUD) == B0) {
+		dev_dbg(&port->dev, "%s: baud was B0\n", __func__);
+		control_state |= TIOCM_DTR | TIOCM_RTS;
+		mct_u232_set_modem_ctrl(port, control_state);
+	}
+
+	mct_u232_set_baud_rate(tty, serial, port, tty_get_baud_rate(tty));
+
+	if ((cflag & CBAUD) == B0) {
+		dev_dbg(&port->dev, "%s: baud is B0\n", __func__);
+		/* Drop RTS and DTR */
+		control_state &= ~(TIOCM_DTR | TIOCM_RTS);
+		mct_u232_set_modem_ctrl(port, control_state);
+	}
+
+	/*
+	 * Update line control register (LCR)
+	 */
+
+	/* set the parity */
+	if (cflag & PARENB)
+		last_lcr |= (cflag & PARODD) ?
+			MCT_U232_PARITY_ODD : MCT_U232_PARITY_EVEN;
+	else
+		last_lcr |= MCT_U232_PARITY_NONE;
+
+	/* set the number of data bits */
+	switch (cflag & CSIZE) {
+	case CS5:
+		last_lcr |= MCT_U232_DATA_BITS_5; break;
+	case CS6:
+		last_lcr |= MCT_U232_DATA_BITS_6; break;
+	case CS7:
+		last_lcr |= MCT_U232_DATA_BITS_7; break;
+	case CS8:
+		last_lcr |= MCT_U232_DATA_BITS_8; break;
+	default:
+		dev_err(&port->dev,
+			"CSIZE was not CS5-CS8, using default of 8\n");
+		last_lcr |= MCT_U232_DATA_BITS_8;
+		break;
+	}
+
+	termios->c_cflag &= ~CMSPAR;
+
+	/* set the number of stop bits */
+	last_lcr |= (cflag & CSTOPB) ?
+		MCT_U232_STOP_BITS_2 : MCT_U232_STOP_BITS_1;
+
+	mct_u232_set_line_ctrl(port, last_lcr);
+
+	/* save off the modified port settings */
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->control_state = control_state;
+	priv->last_lcr = last_lcr;
+	spin_unlock_irqrestore(&priv->lock, flags);
+} /* mct_u232_set_termios */
+
+static void mct_u232_break_ctl(struct tty_struct *tty, int break_state)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+	unsigned char lcr;
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	lcr = priv->last_lcr;
+
+	if (break_state)
+		lcr |= MCT_U232_SET_BREAK;
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	mct_u232_set_line_ctrl(port, lcr);
+} /* mct_u232_break_ctl */
+
+
+static int mct_u232_tiocmget(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+	unsigned int control_state;
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	control_state = priv->control_state;
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return control_state;
+}
+
+static int mct_u232_tiocmset(struct tty_struct *tty,
+			      unsigned int set, unsigned int clear)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+	unsigned int control_state;
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	control_state = priv->control_state;
+
+	if (set & TIOCM_RTS)
+		control_state |= TIOCM_RTS;
+	if (set & TIOCM_DTR)
+		control_state |= TIOCM_DTR;
+	if (clear & TIOCM_RTS)
+		control_state &= ~TIOCM_RTS;
+	if (clear & TIOCM_DTR)
+		control_state &= ~TIOCM_DTR;
+
+	priv->control_state = control_state;
+	spin_unlock_irqrestore(&priv->lock, flags);
+	return mct_u232_set_modem_ctrl(port, control_state);
+}
+
+static void mct_u232_throttle(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+	unsigned int control_state;
+
+	spin_lock_irq(&priv->lock);
+	priv->rx_flags |= THROTTLED;
+	if (C_CRTSCTS(tty)) {
+		priv->control_state &= ~TIOCM_RTS;
+		control_state = priv->control_state;
+		spin_unlock_irq(&priv->lock);
+		mct_u232_set_modem_ctrl(port, control_state);
+	} else {
+		spin_unlock_irq(&priv->lock);
+	}
+}
+
+static void mct_u232_unthrottle(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct mct_u232_private *priv = usb_get_serial_port_data(port);
+	unsigned int control_state;
+
+	spin_lock_irq(&priv->lock);
+	if ((priv->rx_flags & THROTTLED) && C_CRTSCTS(tty)) {
+		priv->rx_flags &= ~THROTTLED;
+		priv->control_state |= TIOCM_RTS;
+		control_state = priv->control_state;
+		spin_unlock_irq(&priv->lock);
+		mct_u232_set_modem_ctrl(port, control_state);
+	} else {
+		spin_unlock_irq(&priv->lock);
+	}
+}
+
+module_usb_serial_driver(serial_drivers, id_table);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");