xen: add kconfig menu

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / net / iseries_veth.c

/* File veth.c created by Kyle A. Lucke on Mon Aug  7 2000. */
/*
 * IBM eServer iSeries Virtual Ethernet Device Driver
 * Copyright (C) 2001 Kyle A. Lucke (klucke@us.ibm.com), IBM Corp.
 * Substantially cleaned up by:
 * Copyright (C) 2003 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
 * Copyright (C) 2004-2005 Michael Ellerman, IBM Corporation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 *
 *
 * This module implements the virtual ethernet device for iSeries LPAR
 * Linux.  It uses hypervisor message passing to implement an
 * ethernet-like network device communicating between partitions on
 * the iSeries.
 *
 * The iSeries LPAR hypervisor currently allows for up to 16 different
 * virtual ethernets.  These are all dynamically configurable on
 * OS/400 partitions, but dynamic configuration is not supported under
 * Linux yet.  An ethXX network device will be created for each
 * virtual ethernet this partition is connected to.
 *
 * - This driver is responsible for routing packets to and from other
 *   partitions.  The MAC addresses used by the virtual ethernets
 *   contains meaning and must not be modified.
 *
 * - Having 2 virtual ethernets to the same remote partition DOES NOT
 *   double the available bandwidth.  The 2 devices will share the
 *   available hypervisor bandwidth.
 *
 * - If you send a packet to your own mac address, it will just be
 *   dropped, you won't get it on the receive side.
 *
 * - Multicast is implemented by sending the frame frame to every
 *   other partition.  It is the responsibility of the receiving
 *   partition to filter the addresses desired.
 *
 * Tunable parameters:
 *
 * VETH_NUMBUFFERS: This compile time option defaults to 120.  It
 * controls how much memory Linux will allocate per remote partition
 * it is communicating with.  It can be thought of as the maximum
 * number of packets outstanding to a remote partition at a time.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/ethtool.h>
#include <linux/if_ether.h>

#include <asm/abs_addr.h>
#include <asm/iseries/mf.h>
#include <asm/uaccess.h>
#include <asm/firmware.h>
#include <asm/iseries/hv_lp_config.h>
#include <asm/iseries/hv_types.h>
#include <asm/iseries/hv_lp_event.h>
#include <asm/iommu.h>
#include <asm/vio.h>

#undef DEBUG

MODULE_AUTHOR("Kyle Lucke <klucke@us.ibm.com>");
MODULE_DESCRIPTION("iSeries Virtual ethernet driver");
MODULE_LICENSE("GPL");

#define VETH_EVENT_CAP  (0)
#define VETH_EVENT_FRAMES       (1)
#define VETH_EVENT_MONITOR      (2)
#define VETH_EVENT_FRAMES_ACK   (3)

#define VETH_MAX_ACKS_PER_MSG   (20)
#define VETH_MAX_FRAMES_PER_MSG (6)

struct veth_frames_data {
        u32 addr[VETH_MAX_FRAMES_PER_MSG];
        u16 len[VETH_MAX_FRAMES_PER_MSG];
        u32 eofmask;
};
#define VETH_EOF_SHIFT          (32-VETH_MAX_FRAMES_PER_MSG)

struct veth_frames_ack_data {
        u16 token[VETH_MAX_ACKS_PER_MSG];
};

struct veth_cap_data {
        u8 caps_version;
        u8 rsvd1;
        u16 num_buffers;
        u16 ack_threshold;
        u16 rsvd2;
        u32 ack_timeout;
        u32 rsvd3;
        u64 rsvd4[3];
};

struct veth_lpevent {
        struct HvLpEvent base_event;
        union {
                struct veth_cap_data caps_data;
                struct veth_frames_data frames_data;
                struct veth_frames_ack_data frames_ack_data;
        } u;

};

#define DRV_NAME        "iseries_veth"
#define DRV_VERSION     "2.0"

#define VETH_NUMBUFFERS         (120)
#define VETH_ACKTIMEOUT         (1000000) /* microseconds */
#define VETH_MAX_MCAST          (12)

#define VETH_MAX_MTU            (9000)

#if VETH_NUMBUFFERS < 10
#define ACK_THRESHOLD           (1)
#elif VETH_NUMBUFFERS < 20
#define ACK_THRESHOLD           (4)
#elif VETH_NUMBUFFERS < 40
#define ACK_THRESHOLD           (10)
#else
#define ACK_THRESHOLD           (20)
#endif

#define VETH_STATE_SHUTDOWN     (0x0001)
#define VETH_STATE_OPEN         (0x0002)
#define VETH_STATE_RESET        (0x0004)
#define VETH_STATE_SENTMON      (0x0008)
#define VETH_STATE_SENTCAPS     (0x0010)
#define VETH_STATE_GOTCAPACK    (0x0020)
#define VETH_STATE_GOTCAPS      (0x0040)
#define VETH_STATE_SENTCAPACK   (0x0080)
#define VETH_STATE_READY        (0x0100)

struct veth_msg {
        struct veth_msg *next;
        struct veth_frames_data data;
        int token;
        int in_use;
        struct sk_buff *skb;
        struct device *dev;
};

struct veth_lpar_connection {
        HvLpIndex remote_lp;
        struct delayed_work statemachine_wq;
        struct veth_msg *msgs;
        int num_events;
        struct veth_cap_data local_caps;

        struct kobject kobject;
        struct timer_list ack_timer;

        struct timer_list reset_timer;
        unsigned int reset_timeout;
        unsigned long last_contact;
        int outstanding_tx;

        spinlock_t lock;
        unsigned long state;
        HvLpInstanceId src_inst;
        HvLpInstanceId dst_inst;
        struct veth_lpevent cap_event, cap_ack_event;
        u16 pending_acks[VETH_MAX_ACKS_PER_MSG];
        u32 num_pending_acks;

        int num_ack_events;
        struct veth_cap_data remote_caps;
        u32 ack_timeout;

        struct veth_msg *msg_stack_head;
};

struct veth_port {
        struct device *dev;
        u64 mac_addr;
        HvLpIndexMap lpar_map;

        /* queue_lock protects the stopped_map and dev's queue. */
        spinlock_t queue_lock;
        HvLpIndexMap stopped_map;

        /* mcast_gate protects promiscuous, num_mcast & mcast_addr. */
        rwlock_t mcast_gate;
        int promiscuous;
        int num_mcast;
        u64 mcast_addr[VETH_MAX_MCAST];

        struct kobject kobject;
};

static HvLpIndex this_lp;
static struct veth_lpar_connection *veth_cnx[HVMAXARCHITECTEDLPS]; /* = 0 */
static struct net_device *veth_dev[HVMAXARCHITECTEDVIRTUALLANS]; /* = 0 */

static int veth_start_xmit(struct sk_buff *skb, struct net_device *dev);
static void veth_recycle_msg(struct veth_lpar_connection *, struct veth_msg *);
static void veth_wake_queues(struct veth_lpar_connection *cnx);
static void veth_stop_queues(struct veth_lpar_connection *cnx);
static void veth_receive(struct veth_lpar_connection *, struct veth_lpevent *);
static void veth_release_connection(struct kobject *kobject);
static void veth_timed_ack(unsigned long ptr);
static void veth_timed_reset(unsigned long ptr);

/*
 * Utility functions
 */

#define veth_info(fmt, args...) \
        printk(KERN_INFO DRV_NAME ": " fmt, ## args)

#define veth_error(fmt, args...) \
        printk(KERN_ERR DRV_NAME ": Error: " fmt, ## args)

#ifdef DEBUG
#define veth_debug(fmt, args...) \
        printk(KERN_DEBUG DRV_NAME ": " fmt, ## args)
#else
#define veth_debug(fmt, args...) do {} while (0)
#endif

/* You must hold the connection's lock when you call this function. */
static inline void veth_stack_push(struct veth_lpar_connection *cnx,
                                   struct veth_msg *msg)
{
        msg->next = cnx->msg_stack_head;
        cnx->msg_stack_head = msg;
}

/* You must hold the connection's lock when you call this function. */
static inline struct veth_msg *veth_stack_pop(struct veth_lpar_connection *cnx)
{
        struct veth_msg *msg;

        msg = cnx->msg_stack_head;
        if (msg)
                cnx->msg_stack_head = cnx->msg_stack_head->next;

        return msg;
}

/* You must hold the connection's lock when you call this function. */
static inline int veth_stack_is_empty(struct veth_lpar_connection *cnx)
{
        return cnx->msg_stack_head == NULL;
}

static inline HvLpEvent_Rc
veth_signalevent(struct veth_lpar_connection *cnx, u16 subtype,
                 HvLpEvent_AckInd ackind, HvLpEvent_AckType acktype,
                 u64 token,
                 u64 data1, u64 data2, u64 data3, u64 data4, u64 data5)
{
        return HvCallEvent_signalLpEventFast(cnx->remote_lp,
                                             HvLpEvent_Type_VirtualLan,
                                             subtype, ackind, acktype,
                                             cnx->src_inst,
                                             cnx->dst_inst,
                                             token, data1, data2, data3,
                                             data4, data5);
}

static inline HvLpEvent_Rc veth_signaldata(struct veth_lpar_connection *cnx,
                                           u16 subtype, u64 token, void *data)
{
        u64 *p = (u64 *) data;

        return veth_signalevent(cnx, subtype, HvLpEvent_AckInd_NoAck,
                                HvLpEvent_AckType_ImmediateAck,
                                token, p[0], p[1], p[2], p[3], p[4]);
}

struct veth_allocation {
        struct completion c;
        int num;
};

static void veth_complete_allocation(void *parm, int number)
{
        struct veth_allocation *vc = (struct veth_allocation *)parm;

        vc->num = number;
        complete(&vc->c);
}

static int veth_allocate_events(HvLpIndex rlp, int number)
{
        struct veth_allocation vc =
                { COMPLETION_INITIALIZER_ONSTACK(vc.c), 0 };

        mf_allocate_lp_events(rlp, HvLpEvent_Type_VirtualLan,
                            sizeof(struct veth_lpevent), number,
                            &veth_complete_allocation, &vc);
        wait_for_completion(&vc.c);

        return vc.num;
}

/*
 * sysfs support
 */

struct veth_cnx_attribute {
        struct attribute attr;
        ssize_t (*show)(struct veth_lpar_connection *, char *buf);
        ssize_t (*store)(struct veth_lpar_connection *, const char *buf);
};

static ssize_t veth_cnx_attribute_show(struct kobject *kobj,
                struct attribute *attr, char *buf)
{
        struct veth_cnx_attribute *cnx_attr;
        struct veth_lpar_connection *cnx;

        cnx_attr = container_of(attr, struct veth_cnx_attribute, attr);
        cnx = container_of(kobj, struct veth_lpar_connection, kobject);

        if (!cnx_attr->show)
                return -EIO;

        return cnx_attr->show(cnx, buf);
}

#define CUSTOM_CNX_ATTR(_name, _format, _expression)                    \
static ssize_t _name##_show(struct veth_lpar_connection *cnx, char *buf)\
{                                                                       \
        return sprintf(buf, _format, _expression);                      \
}                                                                       \
struct veth_cnx_attribute veth_cnx_attr_##_name = __ATTR_RO(_name)

#define SIMPLE_CNX_ATTR(_name)  \
        CUSTOM_CNX_ATTR(_name, "%lu\n", (unsigned long)cnx->_name)

SIMPLE_CNX_ATTR(outstanding_tx);
SIMPLE_CNX_ATTR(remote_lp);
SIMPLE_CNX_ATTR(num_events);
SIMPLE_CNX_ATTR(src_inst);
SIMPLE_CNX_ATTR(dst_inst);
SIMPLE_CNX_ATTR(num_pending_acks);
SIMPLE_CNX_ATTR(num_ack_events);
CUSTOM_CNX_ATTR(ack_timeout, "%d\n", jiffies_to_msecs(cnx->ack_timeout));
CUSTOM_CNX_ATTR(reset_timeout, "%d\n", jiffies_to_msecs(cnx->reset_timeout));
CUSTOM_CNX_ATTR(state, "0x%.4lX\n", cnx->state);
CUSTOM_CNX_ATTR(last_contact, "%d\n", cnx->last_contact ?
                jiffies_to_msecs(jiffies - cnx->last_contact) : 0);

#define GET_CNX_ATTR(_name)     (&veth_cnx_attr_##_name.attr)

static struct attribute *veth_cnx_default_attrs[] = {
        GET_CNX_ATTR(outstanding_tx),
        GET_CNX_ATTR(remote_lp),
        GET_CNX_ATTR(num_events),
        GET_CNX_ATTR(reset_timeout),
        GET_CNX_ATTR(last_contact),
        GET_CNX_ATTR(state),
        GET_CNX_ATTR(src_inst),
        GET_CNX_ATTR(dst_inst),
        GET_CNX_ATTR(num_pending_acks),
        GET_CNX_ATTR(num_ack_events),
        GET_CNX_ATTR(ack_timeout),
        NULL
};

static struct sysfs_ops veth_cnx_sysfs_ops = {
                .show = veth_cnx_attribute_show
};

static struct kobj_type veth_lpar_connection_ktype = {
        .release        = veth_release_connection,
        .sysfs_ops      = &veth_cnx_sysfs_ops,
        .default_attrs  = veth_cnx_default_attrs
};

struct veth_port_attribute {
        struct attribute attr;
        ssize_t (*show)(struct veth_port *, char *buf);
        ssize_t (*store)(struct veth_port *, const char *buf);
};

static ssize_t veth_port_attribute_show(struct kobject *kobj,
                struct attribute *attr, char *buf)
{
        struct veth_port_attribute *port_attr;
        struct veth_port *port;

        port_attr = container_of(attr, struct veth_port_attribute, attr);
        port = container_of(kobj, struct veth_port, kobject);

        if (!port_attr->show)
                return -EIO;

        return port_attr->show(port, buf);
}

#define CUSTOM_PORT_ATTR(_name, _format, _expression)                   \
static ssize_t _name##_show(struct veth_port *port, char *buf)          \
{                                                                       \
        return sprintf(buf, _format, _expression);                      \
}                                                                       \
struct veth_port_attribute veth_port_attr_##_name = __ATTR_RO(_name)

#define SIMPLE_PORT_ATTR(_name) \
        CUSTOM_PORT_ATTR(_name, "%lu\n", (unsigned long)port->_name)

SIMPLE_PORT_ATTR(promiscuous);
SIMPLE_PORT_ATTR(num_mcast);
CUSTOM_PORT_ATTR(lpar_map, "0x%X\n", port->lpar_map);
CUSTOM_PORT_ATTR(stopped_map, "0x%X\n", port->stopped_map);
CUSTOM_PORT_ATTR(mac_addr, "0x%llX\n", port->mac_addr);

#define GET_PORT_ATTR(_name)    (&veth_port_attr_##_name.attr)
static struct attribute *veth_port_default_attrs[] = {
        GET_PORT_ATTR(mac_addr),
        GET_PORT_ATTR(lpar_map),
        GET_PORT_ATTR(stopped_map),
        GET_PORT_ATTR(promiscuous),
        GET_PORT_ATTR(num_mcast),
        NULL
};

static struct sysfs_ops veth_port_sysfs_ops = {
        .show = veth_port_attribute_show
};

static struct kobj_type veth_port_ktype = {
        .sysfs_ops      = &veth_port_sysfs_ops,
        .default_attrs  = veth_port_default_attrs
};

/*
 * LPAR connection code
 */

static inline void veth_kick_statemachine(struct veth_lpar_connection *cnx)
{
        schedule_delayed_work(&cnx->statemachine_wq, 0);
}

static void veth_take_cap(struct veth_lpar_connection *cnx,
                          struct veth_lpevent *event)
{
        unsigned long flags;

        spin_lock_irqsave(&cnx->lock, flags);
        /* Receiving caps may mean the other end has just come up, so
         * we need to reload the instance ID of the far end */
        cnx->dst_inst =
                HvCallEvent_getTargetLpInstanceId(cnx->remote_lp,
                                                  HvLpEvent_Type_VirtualLan);

        if (cnx->state & VETH_STATE_GOTCAPS) {
                veth_error("Received a second capabilities from LPAR %d.\n",
                           cnx->remote_lp);
                event->base_event.xRc = HvLpEvent_Rc_BufferNotAvailable;
                HvCallEvent_ackLpEvent((struct HvLpEvent *) event);
        } else {
                memcpy(&cnx->cap_event, event, sizeof(cnx->cap_event));
                cnx->state |= VETH_STATE_GOTCAPS;
                veth_kick_statemachine(cnx);
        }
        spin_unlock_irqrestore(&cnx->lock, flags);
}

static void veth_take_cap_ack(struct veth_lpar_connection *cnx,
                              struct veth_lpevent *event)
{
        unsigned long flags;

        spin_lock_irqsave(&cnx->lock, flags);
        if (cnx->state & VETH_STATE_GOTCAPACK) {
                veth_error("Received a second capabilities ack from LPAR %d.\n",
                           cnx->remote_lp);
        } else {
                memcpy(&cnx->cap_ack_event, event,
                       sizeof(cnx->cap_ack_event));
                cnx->state |= VETH_STATE_GOTCAPACK;
                veth_kick_statemachine(cnx);
        }
        spin_unlock_irqrestore(&cnx->lock, flags);
}

static void veth_take_monitor_ack(struct veth_lpar_connection *cnx,
                                  struct veth_lpevent *event)
{
        unsigned long flags;

        spin_lock_irqsave(&cnx->lock, flags);
        veth_debug("cnx %d: lost connection.\n", cnx->remote_lp);

        /* Avoid kicking the statemachine once we're shutdown.
         * It's unnecessary and it could break veth_stop_connection(). */

        if (! (cnx->state & VETH_STATE_SHUTDOWN)) {
                cnx->state |= VETH_STATE_RESET;
                veth_kick_statemachine(cnx);
        }
        spin_unlock_irqrestore(&cnx->lock, flags);
}

static void veth_handle_ack(struct veth_lpevent *event)
{
        HvLpIndex rlp = event->base_event.xTargetLp;
        struct veth_lpar_connection *cnx = veth_cnx[rlp];

        BUG_ON(! cnx);

        switch (event->base_event.xSubtype) {
        case VETH_EVENT_CAP:
                veth_take_cap_ack(cnx, event);
                break;
        case VETH_EVENT_MONITOR:
                veth_take_monitor_ack(cnx, event);
                break;
        default:
                veth_error("Unknown ack type %d from LPAR %d.\n",
                                event->base_event.xSubtype, rlp);
        };
}

static void veth_handle_int(struct veth_lpevent *event)
{
        HvLpIndex rlp = event->base_event.xSourceLp;
        struct veth_lpar_connection *cnx = veth_cnx[rlp];
        unsigned long flags;
        int i, acked = 0;

        BUG_ON(! cnx);

        switch (event->base_event.xSubtype) {
        case VETH_EVENT_CAP:
                veth_take_cap(cnx, event);
                break;
        case VETH_EVENT_MONITOR:
                /* do nothing... this'll hang out here til we're dead,
                 * and the hypervisor will return it for us. */
                break;
        case VETH_EVENT_FRAMES_ACK:
                spin_lock_irqsave(&cnx->lock, flags);

                for (i = 0; i < VETH_MAX_ACKS_PER_MSG; ++i) {
                        u16 msgnum = event->u.frames_ack_data.token[i];

                        if (msgnum < VETH_NUMBUFFERS) {
                                veth_recycle_msg(cnx, cnx->msgs + msgnum);
                                cnx->outstanding_tx--;
                                acked++;
                        }
                }

                if (acked > 0) {
                        cnx->last_contact = jiffies;
                        veth_wake_queues(cnx);
                }

                spin_unlock_irqrestore(&cnx->lock, flags);
                break;
        case VETH_EVENT_FRAMES:
                veth_receive(cnx, event);
                break;
        default:
                veth_error("Unknown interrupt type %d from LPAR %d.\n",
                                event->base_event.xSubtype, rlp);
        };
}

static void veth_handle_event(struct HvLpEvent *event)
{
        struct veth_lpevent *veth_event = (struct veth_lpevent *)event;

        if (hvlpevent_is_ack(event))
                veth_handle_ack(veth_event);
        else
                veth_handle_int(veth_event);
}

static int veth_process_caps(struct veth_lpar_connection *cnx)
{
        struct veth_cap_data *remote_caps = &cnx->remote_caps;
        int num_acks_needed;

        /* Convert timer to jiffies */
        cnx->ack_timeout = remote_caps->ack_timeout * HZ / 1000000;

        if ( (remote_caps->num_buffers == 0) ||
             (remote_caps->ack_threshold > VETH_MAX_ACKS_PER_MSG) ||
             (remote_caps->ack_threshold == 0) ||
             (cnx->ack_timeout == 0) ) {
                veth_error("Received incompatible capabilities from LPAR %d.\n",
                                cnx->remote_lp);
                return HvLpEvent_Rc_InvalidSubtypeData;
        }

        num_acks_needed = (remote_caps->num_buffers
                           / remote_caps->ack_threshold) + 1;

        /* FIXME: locking on num_ack_events? */
        if (cnx->num_ack_events < num_acks_needed) {
                int num;

                num = veth_allocate_events(cnx->remote_lp,
                                           num_acks_needed-cnx->num_ack_events);
                if (num > 0)
                        cnx->num_ack_events += num;

                if (cnx->num_ack_events < num_acks_needed) {
                        veth_error("Couldn't allocate enough ack events "
                                        "for LPAR %d.\n", cnx->remote_lp);

                        return HvLpEvent_Rc_BufferNotAvailable;
                }
        }


        return HvLpEvent_Rc_Good;
}

/* FIXME: The gotos here are a bit dubious */
static void veth_statemachine(struct work_struct *work)
{
        struct veth_lpar_connection *cnx =
                container_of(work, struct veth_lpar_connection,
                             statemachine_wq.work);
        int rlp = cnx->remote_lp;
        int rc;

        spin_lock_irq(&cnx->lock);

 restart:
        if (cnx->state & VETH_STATE_RESET) {
                if (cnx->state & VETH_STATE_OPEN)
                        HvCallEvent_closeLpEventPath(cnx->remote_lp,
                                                     HvLpEvent_Type_VirtualLan);

                /*
                 * Reset ack data. This prevents the ack_timer actually
                 * doing anything, even if it runs one more time when
                 * we drop the lock below.
                 */
                memset(&cnx->pending_acks, 0xff, sizeof (cnx->pending_acks));
                cnx->num_pending_acks = 0;

                cnx->state &= ~(VETH_STATE_RESET | VETH_STATE_SENTMON
                                | VETH_STATE_OPEN | VETH_STATE_SENTCAPS
                                | VETH_STATE_GOTCAPACK | VETH_STATE_GOTCAPS
                                | VETH_STATE_SENTCAPACK | VETH_STATE_READY);

                /* Clean up any leftover messages */
                if (cnx->msgs) {
                        int i;
                        for (i = 0; i < VETH_NUMBUFFERS; ++i)
                                veth_recycle_msg(cnx, cnx->msgs + i);
                }

                cnx->outstanding_tx = 0;
                veth_wake_queues(cnx);

                /* Drop the lock so we can do stuff that might sleep or
                 * take other locks. */
                spin_unlock_irq(&cnx->lock);

                del_timer_sync(&cnx->ack_timer);
                del_timer_sync(&cnx->reset_timer);

                spin_lock_irq(&cnx->lock);

                if (cnx->state & VETH_STATE_RESET)
                        goto restart;

                /* Hack, wait for the other end to reset itself. */
                if (! (cnx->state & VETH_STATE_SHUTDOWN)) {
                        schedule_delayed_work(&cnx->statemachine_wq, 5 * HZ);
                        goto out;
                }
        }

        if (cnx->state & VETH_STATE_SHUTDOWN)
                /* It's all over, do nothing */
                goto out;

        if ( !(cnx->state & VETH_STATE_OPEN) ) {
                if (! cnx->msgs || (cnx->num_events < (2 + VETH_NUMBUFFERS)) )
                        goto cant_cope;

                HvCallEvent_openLpEventPath(rlp, HvLpEvent_Type_VirtualLan);
                cnx->src_inst =
                        HvCallEvent_getSourceLpInstanceId(rlp,
                                                          HvLpEvent_Type_VirtualLan);
                cnx->dst_inst =
                        HvCallEvent_getTargetLpInstanceId(rlp,
                                                          HvLpEvent_Type_VirtualLan);
                cnx->state |= VETH_STATE_OPEN;
        }

        if ( (cnx->state & VETH_STATE_OPEN) &&
             !(cnx->state & VETH_STATE_SENTMON) ) {
                rc = veth_signalevent(cnx, VETH_EVENT_MONITOR,
                                      HvLpEvent_AckInd_DoAck,
                                      HvLpEvent_AckType_DeferredAck,
                                      0, 0, 0, 0, 0, 0);

                if (rc == HvLpEvent_Rc_Good) {
                        cnx->state |= VETH_STATE_SENTMON;
                } else {
                        if ( (rc != HvLpEvent_Rc_PartitionDead) &&
                             (rc != HvLpEvent_Rc_PathClosed) )
                                veth_error("Error sending monitor to LPAR %d, "
                                                "rc = %d\n", rlp, rc);

                        /* Oh well, hope we get a cap from the other
                         * end and do better when that kicks us */
                        goto out;
                }
        }

        if ( (cnx->state & VETH_STATE_OPEN) &&
             !(cnx->state & VETH_STATE_SENTCAPS)) {
                u64 *rawcap = (u64 *)&cnx->local_caps;

                rc = veth_signalevent(cnx, VETH_EVENT_CAP,
                                      HvLpEvent_AckInd_DoAck,
                                      HvLpEvent_AckType_ImmediateAck,
                                      0, rawcap[0], rawcap[1], rawcap[2],
                                      rawcap[3], rawcap[4]);

                if (rc == HvLpEvent_Rc_Good) {
                        cnx->state |= VETH_STATE_SENTCAPS;
                } else {
                        if ( (rc != HvLpEvent_Rc_PartitionDead) &&
                             (rc != HvLpEvent_Rc_PathClosed) )
                                veth_error("Error sending caps to LPAR %d, "
                                                "rc = %d\n", rlp, rc);

                        /* Oh well, hope we get a cap from the other
                         * end and do better when that kicks us */
                        goto out;
                }
        }

        if ((cnx->state & VETH_STATE_GOTCAPS) &&
            !(cnx->state & VETH_STATE_SENTCAPACK)) {
                struct veth_cap_data *remote_caps = &cnx->remote_caps;

                memcpy(remote_caps, &cnx->cap_event.u.caps_data,
                       sizeof(*remote_caps));

                spin_unlock_irq(&cnx->lock);
                rc = veth_process_caps(cnx);
                spin_lock_irq(&cnx->lock);

                /* We dropped the lock, so recheck for anything which
                 * might mess us up */
                if (cnx->state & (VETH_STATE_RESET|VETH_STATE_SHUTDOWN))
                        goto restart;

                cnx->cap_event.base_event.xRc = rc;
                HvCallEvent_ackLpEvent((struct HvLpEvent *)&cnx->cap_event);
                if (rc == HvLpEvent_Rc_Good)
                        cnx->state |= VETH_STATE_SENTCAPACK;
                else
                        goto cant_cope;
        }

        if ((cnx->state & VETH_STATE_GOTCAPACK) &&
            (cnx->state & VETH_STATE_GOTCAPS) &&
            !(cnx->state & VETH_STATE_READY)) {
                if (cnx->cap_ack_event.base_event.xRc == HvLpEvent_Rc_Good) {
                        /* Start the ACK timer */
                        cnx->ack_timer.expires = jiffies + cnx->ack_timeout;
                        add_timer(&cnx->ack_timer);
                        cnx->state |= VETH_STATE_READY;
                } else {
                        veth_error("Caps rejected by LPAR %d, rc = %d\n",
                                        rlp, cnx->cap_ack_event.base_event.xRc);
                        goto cant_cope;
                }
        }

 out:
        spin_unlock_irq(&cnx->lock);
        return;

 cant_cope:
        /* FIXME: we get here if something happens we really can't
         * cope with.  The link will never work once we get here, and
         * all we can do is not lock the rest of the system up */
        veth_error("Unrecoverable error on connection to LPAR %d, shutting down"
                        " (state = 0x%04lx)\n", rlp, cnx->state);
        cnx->state |= VETH_STATE_SHUTDOWN;
        spin_unlock_irq(&cnx->lock);
}

static int veth_init_connection(u8 rlp)
{
        struct veth_lpar_connection *cnx;
        struct veth_msg *msgs;
        int i;

        if ( (rlp == this_lp) ||
             ! HvLpConfig_doLpsCommunicateOnVirtualLan(this_lp, rlp) )
                return 0;

        cnx = kzalloc(sizeof(*cnx), GFP_KERNEL);
        if (! cnx)
                return -ENOMEM;

        cnx->remote_lp = rlp;
        spin_lock_init(&cnx->lock);
        INIT_DELAYED_WORK(&cnx->statemachine_wq, veth_statemachine);

        init_timer(&cnx->ack_timer);
        cnx->ack_timer.function = veth_timed_ack;
        cnx->ack_timer.data = (unsigned long) cnx;

        init_timer(&cnx->reset_timer);
        cnx->reset_timer.function = veth_timed_reset;
        cnx->reset_timer.data = (unsigned long) cnx;
        cnx->reset_timeout = 5 * HZ * (VETH_ACKTIMEOUT / 1000000);

        memset(&cnx->pending_acks, 0xff, sizeof (cnx->pending_acks));

        veth_cnx[rlp] = cnx;

        /* This gets us 1 reference, which is held on behalf of the driver
         * infrastructure. It's released at module unload. */
        kobject_init(&cnx->kobject, &veth_lpar_connection_ktype);

        msgs = kcalloc(VETH_NUMBUFFERS, sizeof(struct veth_msg), GFP_KERNEL);
        if (! msgs) {
                veth_error("Can't allocate buffers for LPAR %d.\n", rlp);
                return -ENOMEM;
        }

        cnx->msgs = msgs;

        for (i = 0; i < VETH_NUMBUFFERS; i++) {
                msgs[i].token = i;
                veth_stack_push(cnx, msgs + i);
        }

        cnx->num_events = veth_allocate_events(rlp, 2 + VETH_NUMBUFFERS);

        if (cnx->num_events < (2 + VETH_NUMBUFFERS)) {
                veth_error("Can't allocate enough events for LPAR %d.\n", rlp);
                return -ENOMEM;
        }

        cnx->local_caps.num_buffers = VETH_NUMBUFFERS;
        cnx->local_caps.ack_threshold = ACK_THRESHOLD;
        cnx->local_caps.ack_timeout = VETH_ACKTIMEOUT;

        return 0;
}

static void veth_stop_connection(struct veth_lpar_connection *cnx)
{
        if (!cnx)
                return;

        spin_lock_irq(&cnx->lock);
        cnx->state |= VETH_STATE_RESET | VETH_STATE_SHUTDOWN;
        veth_kick_statemachine(cnx);
        spin_unlock_irq(&cnx->lock);

        /* There's a slim chance the reset code has just queued the
         * statemachine to run in five seconds. If so we need to cancel
         * that and requeue the work to run now. */
        if (cancel_delayed_work(&cnx->statemachine_wq)) {
                spin_lock_irq(&cnx->lock);
                veth_kick_statemachine(cnx);
                spin_unlock_irq(&cnx->lock);
        }

        /* Wait for the state machine to run. */
        flush_scheduled_work();
}

static void veth_destroy_connection(struct veth_lpar_connection *cnx)
{
        if (!cnx)
                return;

        if (cnx->num_events > 0)
                mf_deallocate_lp_events(cnx->remote_lp,
                                      HvLpEvent_Type_VirtualLan,
                                      cnx->num_events,
                                      NULL, NULL);
        if (cnx->num_ack_events > 0)
                mf_deallocate_lp_events(cnx->remote_lp,
                                      HvLpEvent_Type_VirtualLan,
                                      cnx->num_ack_events,
                                      NULL, NULL);

        kfree(cnx->msgs);
        veth_cnx[cnx->remote_lp] = NULL;
        kfree(cnx);
}

static void veth_release_connection(struct kobject *kobj)
{
        struct veth_lpar_connection *cnx;
        cnx = container_of(kobj, struct veth_lpar_connection, kobject);
        veth_stop_connection(cnx);
        veth_destroy_connection(cnx);
}

/*
 * net_device code
 */

static int veth_open(struct net_device *dev)
{
        netif_start_queue(dev);
        return 0;
}

static int veth_close(struct net_device *dev)
{
        netif_stop_queue(dev);
        return 0;
}

static int veth_change_mtu(struct net_device *dev, int new_mtu)
{
        if ((new_mtu < 68) || (new_mtu > VETH_MAX_MTU))
                return -EINVAL;
        dev->mtu = new_mtu;
        return 0;
}

static void veth_set_multicast_list(struct net_device *dev)
{
        struct veth_port *port = netdev_priv(dev);
        unsigned long flags;

        write_lock_irqsave(&port->mcast_gate, flags);

        if ((dev->flags & IFF_PROMISC) || (dev->flags & IFF_ALLMULTI) ||
                        (netdev_mc_count(dev) > VETH_MAX_MCAST)) {
                port->promiscuous = 1;
        } else {
                struct dev_mc_list *dmi;

                port->promiscuous = 0;

                /* Update table */
                port->num_mcast = 0;

                netdev_for_each_mc_addr(dmi, dev) {
                        u8 *addr = dmi->dmi_addr;
                        u64 xaddr = 0;

                        if (addr[0] & 0x01) {/* multicast address? */
                                memcpy(&xaddr, addr, ETH_ALEN);
                                port->mcast_addr[port->num_mcast] = xaddr;
                                port->num_mcast++;
                        }
                }
        }

        write_unlock_irqrestore(&port->mcast_gate, flags);
}

static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
        strncpy(info->driver, DRV_NAME, sizeof(info->driver) - 1);
        info->driver[sizeof(info->driver) - 1] = '\0';
        strncpy(info->version, DRV_VERSION, sizeof(info->version) - 1);
        info->version[sizeof(info->version) - 1] = '\0';
}

static int veth_get_settings(struct net_device *dev, struct ethtool_cmd *ecmd)
{
        ecmd->supported = (SUPPORTED_1000baseT_Full
                          | SUPPORTED_Autoneg | SUPPORTED_FIBRE);
        ecmd->advertising = (SUPPORTED_1000baseT_Full
                            | SUPPORTED_Autoneg | SUPPORTED_FIBRE);
        ecmd->port = PORT_FIBRE;
        ecmd->transceiver = XCVR_INTERNAL;
        ecmd->phy_address = 0;
        ecmd->speed = SPEED_1000;
        ecmd->duplex = DUPLEX_FULL;
        ecmd->autoneg = AUTONEG_ENABLE;
        ecmd->maxtxpkt = 120;
        ecmd->maxrxpkt = 120;
        return 0;
}

static u32 veth_get_link(struct net_device *dev)
{
        return 1;
}

static const struct ethtool_ops ops = {
        .get_drvinfo = veth_get_drvinfo,
        .get_settings = veth_get_settings,
        .get_link = veth_get_link,
};

static const struct net_device_ops veth_netdev_ops = {
        .ndo_open               = veth_open,
        .ndo_stop               = veth_close,
        .ndo_start_xmit         = veth_start_xmit,
        .ndo_change_mtu         = veth_change_mtu,
        .ndo_set_multicast_list = veth_set_multicast_list,
        .ndo_set_mac_address    = NULL,
        .ndo_validate_addr      = eth_validate_addr,
};

static struct net_device *veth_probe_one(int vlan,
                struct vio_dev *vio_dev)
{
        struct net_device *dev;
        struct veth_port *port;
        struct device *vdev = &vio_dev->dev;
        int i, rc;
        const unsigned char *mac_addr;

        mac_addr = vio_get_attribute(vio_dev, "local-mac-address", NULL);
        if (mac_addr == NULL)
                mac_addr = vio_get_attribute(vio_dev, "mac-address", NULL);
        if (mac_addr == NULL) {
                veth_error("Unable to fetch MAC address from device tree.\n");
                return NULL;
        }

        dev = alloc_etherdev(sizeof (struct veth_port));
        if (! dev) {
                veth_error("Unable to allocate net_device structure!\n");
                return NULL;
        }

        port = netdev_priv(dev);

        spin_lock_init(&port->queue_lock);
        rwlock_init(&port->mcast_gate);
        port->stopped_map = 0;

        for (i = 0; i < HVMAXARCHITECTEDLPS; i++) {
                HvLpVirtualLanIndexMap map;

                if (i == this_lp)
                        continue;
                map = HvLpConfig_getVirtualLanIndexMapForLp(i);
                if (map & (0x8000 >> vlan))
                        port->lpar_map |= (1 << i);
        }
        port->dev = vdev;

        memcpy(dev->dev_addr, mac_addr, ETH_ALEN);

        dev->mtu = VETH_MAX_MTU;

        memcpy(&port->mac_addr, mac_addr, ETH_ALEN);

        dev->netdev_ops = &veth_netdev_ops;
        SET_ETHTOOL_OPS(dev, &ops);

        SET_NETDEV_DEV(dev, vdev);

        rc = register_netdev(dev);
        if (rc != 0) {
                veth_error("Failed registering net device for vlan%d.\n", vlan);
                free_netdev(dev);
                return NULL;
        }

        kobject_init(&port->kobject, &veth_port_ktype);
        if (0 != kobject_add(&port->kobject, &dev->dev.kobj, "veth_port"))
                veth_error("Failed adding port for %s to sysfs.\n", dev->name);

        veth_info("%s attached to iSeries vlan %d (LPAR map = 0x%.4X)\n",
                        dev->name, vlan, port->lpar_map);

        return dev;
}

/*
 * Tx path
 */

static int veth_transmit_to_one(struct sk_buff *skb, HvLpIndex rlp,
                                struct net_device *dev)
{
        struct veth_lpar_connection *cnx = veth_cnx[rlp];
        struct veth_port *port = netdev_priv(dev);
        HvLpEvent_Rc rc;
        struct veth_msg *msg = NULL;
        unsigned long flags;

        if (! cnx)
                return 0;

        spin_lock_irqsave(&cnx->lock, flags);

        if (! (cnx->state & VETH_STATE_READY))
                goto no_error;

        if ((skb->len - ETH_HLEN) > VETH_MAX_MTU)
                goto drop;

        msg = veth_stack_pop(cnx);
        if (! msg)
                goto drop;

        msg->in_use = 1;
        msg->skb = skb_get(skb);

        msg->data.addr[0] = dma_map_single(port->dev, skb->data,
                                skb->len, DMA_TO_DEVICE);

        if (dma_mapping_error(port->dev, msg->data.addr[0]))
                goto recycle_and_drop;

        msg->dev = port->dev;
        msg->data.len[0] = skb->len;
        msg->data.eofmask = 1 << VETH_EOF_SHIFT;

        rc = veth_signaldata(cnx, VETH_EVENT_FRAMES, msg->token, &msg->data);

        if (rc != HvLpEvent_Rc_Good)
                goto recycle_and_drop;

        /* If the timer's not already running, start it now. */
        if (0 == cnx->outstanding_tx)
                mod_timer(&cnx->reset_timer, jiffies + cnx->reset_timeout);

        cnx->last_contact = jiffies;
        cnx->outstanding_tx++;

        if (veth_stack_is_empty(cnx))
                veth_stop_queues(cnx);

 no_error:
        spin_unlock_irqrestore(&cnx->lock, flags);
        return 0;

 recycle_and_drop:
        veth_recycle_msg(cnx, msg);
 drop:
        spin_unlock_irqrestore(&cnx->lock, flags);
        return 1;
}

static void veth_transmit_to_many(struct sk_buff *skb,
                                          HvLpIndexMap lpmask,
                                          struct net_device *dev)
{
        int i, success, error;

        success = error = 0;

        for (i = 0; i < HVMAXARCHITECTEDLPS; i++) {
                if ((lpmask & (1 << i)) == 0)
                        continue;

                if (veth_transmit_to_one(skb, i, dev))
                        error = 1;
                else
                        success = 1;
        }

        if (error)
                dev->stats.tx_errors++;

        if (success) {
                dev->stats.tx_packets++;
                dev->stats.tx_bytes += skb->len;
        }
}

static int veth_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        unsigned char *frame = skb->data;
        struct veth_port *port = netdev_priv(dev);
        HvLpIndexMap lpmask;

        if (! (frame[0] & 0x01)) {
                /* unicast packet */
                HvLpIndex rlp = frame[5];

                if ( ! ((1 << rlp) & port->lpar_map) ) {
                        dev_kfree_skb(skb);
                        return NETDEV_TX_OK;
                }

                lpmask = 1 << rlp;
        } else {
                lpmask = port->lpar_map;
        }

        veth_transmit_to_many(skb, lpmask, dev);

        dev_kfree_skb(skb);

        return NETDEV_TX_OK;
}

/* You must hold the connection's lock when you call this function. */
static void veth_recycle_msg(struct veth_lpar_connection *cnx,
                             struct veth_msg *msg)
{
        u32 dma_address, dma_length;

        if (msg->in_use) {
                msg->in_use = 0;
                dma_address = msg->data.addr[0];
                dma_length = msg->data.len[0];

                if (!dma_mapping_error(msg->dev, dma_address))
                        dma_unmap_single(msg->dev, dma_address, dma_length,
                                        DMA_TO_DEVICE);

                if (msg->skb) {
                        dev_kfree_skb_any(msg->skb);
                        msg->skb = NULL;
                }

                memset(&msg->data, 0, sizeof(msg->data));
                veth_stack_push(cnx, msg);
        } else if (cnx->state & VETH_STATE_OPEN) {
                veth_error("Non-pending frame (# %d) acked by LPAR %d.\n",
                                cnx->remote_lp, msg->token);
        }
}

static void veth_wake_queues(struct veth_lpar_connection *cnx)
{
        int i;

        for (i = 0; i < HVMAXARCHITECTEDVIRTUALLANS; i++) {
                struct net_device *dev = veth_dev[i];
                struct veth_port *port;
                unsigned long flags;

                if (! dev)
                        continue;

                port = netdev_priv(dev);

                if (! (port->lpar_map & (1<<cnx->remote_lp)))
                        continue;

                spin_lock_irqsave(&port->queue_lock, flags);

                port->stopped_map &= ~(1 << cnx->remote_lp);

                if (0 == port->stopped_map && netif_queue_stopped(dev)) {
                        veth_debug("cnx %d: woke queue for %s.\n",
                                        cnx->remote_lp, dev->name);
                        netif_wake_queue(dev);
                }
                spin_unlock_irqrestore(&port->queue_lock, flags);
        }
}

static void veth_stop_queues(struct veth_lpar_connection *cnx)
{
        int i;

        for (i = 0; i < HVMAXARCHITECTEDVIRTUALLANS; i++) {
                struct net_device *dev = veth_dev[i];
                struct veth_port *port;

                if (! dev)
                        continue;

                port = netdev_priv(dev);

                /* If this cnx is not on the vlan for this port, continue */
                if (! (port->lpar_map & (1 << cnx->remote_lp)))
                        continue;

                spin_lock(&port->queue_lock);

                netif_stop_queue(dev);
                port->stopped_map |= (1 << cnx->remote_lp);

                veth_debug("cnx %d: stopped queue for %s, map = 0x%x.\n",
                                cnx->remote_lp, dev->name, port->stopped_map);

                spin_unlock(&port->queue_lock);
        }
}

static void veth_timed_reset(unsigned long ptr)
{
        struct veth_lpar_connection *cnx = (struct veth_lpar_connection *)ptr;
        unsigned long trigger_time, flags;

        /* FIXME is it possible this fires after veth_stop_connection()?
         * That would reschedule the statemachine for 5 seconds and probably
         * execute it after the module's been unloaded. Hmm. */

        spin_lock_irqsave(&cnx->lock, flags);

        if (cnx->outstanding_tx > 0) {
                trigger_time = cnx->last_contact + cnx->reset_timeout;

                if (trigger_time < jiffies) {
                        cnx->state |= VETH_STATE_RESET;
                        veth_kick_statemachine(cnx);
                        veth_error("%d packets not acked by LPAR %d within %d "
                                        "seconds, resetting.\n",
                                        cnx->outstanding_tx, cnx->remote_lp,
                                        cnx->reset_timeout / HZ);
                } else {
                        /* Reschedule the timer */
                        trigger_time = jiffies + cnx->reset_timeout;
                        mod_timer(&cnx->reset_timer, trigger_time);
                }
        }

        spin_unlock_irqrestore(&cnx->lock, flags);
}

/*
 * Rx path
 */

static inline int veth_frame_wanted(struct veth_port *port, u64 mac_addr)
{
        int wanted = 0;
        int i;
        unsigned long flags;

        if ( (mac_addr == port->mac_addr) || (mac_addr == 0xffffffffffff0000) )
                return 1;

        read_lock_irqsave(&port->mcast_gate, flags);

        if (port->promiscuous) {
                wanted = 1;
                goto out;
        }

        for (i = 0; i < port->num_mcast; ++i) {
                if (port->mcast_addr[i] == mac_addr) {
                        wanted = 1;
                        break;
                }
        }

 out:
        read_unlock_irqrestore(&port->mcast_gate, flags);

        return wanted;
}

struct dma_chunk {
        u64 addr;
        u64 size;
};

#define VETH_MAX_PAGES_PER_FRAME ( (VETH_MAX_MTU+PAGE_SIZE-2)/PAGE_SIZE + 1 )

static inline void veth_build_dma_list(struct dma_chunk *list,
                                       unsigned char *p, unsigned long length)
{
        unsigned long done;
        int i = 1;

        /* FIXME: skbs are contiguous in real addresses.  Do we
         * really need to break it into PAGE_SIZE chunks, or can we do
         * it just at the granularity of iSeries real->absolute
         * mapping?  Indeed, given the way the allocator works, can we
         * count on them being absolutely contiguous? */
        list[0].addr = iseries_hv_addr(p);
        list[0].size = min(length,
                           PAGE_SIZE - ((unsigned long)p & ~PAGE_MASK));

        done = list[0].size;
        while (done < length) {
                list[i].addr = iseries_hv_addr(p + done);
                list[i].size = min(length-done, PAGE_SIZE);
                done += list[i].size;
                i++;
        }
}

static void veth_flush_acks(struct veth_lpar_connection *cnx)
{
        HvLpEvent_Rc rc;

        rc = veth_signaldata(cnx, VETH_EVENT_FRAMES_ACK,
                             0, &cnx->pending_acks);

        if (rc != HvLpEvent_Rc_Good)
                veth_error("Failed acking frames from LPAR %d, rc = %d\n",
                                cnx->remote_lp, (int)rc);

        cnx->num_pending_acks = 0;
        memset(&cnx->pending_acks, 0xff, sizeof(cnx->pending_acks));
}

static void veth_receive(struct veth_lpar_connection *cnx,
                         struct veth_lpevent *event)
{
        struct veth_frames_data *senddata = &event->u.frames_data;
        int startchunk = 0;
        int nchunks;
        unsigned long flags;
        HvLpDma_Rc rc;

        do {
                u16 length = 0;
                struct sk_buff *skb;
                struct dma_chunk local_list[VETH_MAX_PAGES_PER_FRAME];
                struct dma_chunk remote_list[VETH_MAX_FRAMES_PER_MSG];
                u64 dest;
                HvLpVirtualLanIndex vlan;
                struct net_device *dev;
                struct veth_port *port;

                /* FIXME: do we need this? */
                memset(local_list, 0, sizeof(local_list));
                memset(remote_list, 0, sizeof(VETH_MAX_FRAMES_PER_MSG));

                /* a 0 address marks the end of the valid entries */
                if (senddata->addr[startchunk] == 0)
                        break;

                /* make sure that we have at least 1 EOF entry in the
                 * remaining entries */
                if (! (senddata->eofmask >> (startchunk + VETH_EOF_SHIFT))) {
                        veth_error("Missing EOF fragment in event "
                                        "eofmask = 0x%x startchunk = %d\n",
                                        (unsigned)senddata->eofmask,
                                        startchunk);
                        break;
                }

                /* build list of chunks in this frame */
                nchunks = 0;
                do {
                        remote_list[nchunks].addr =
                                (u64) senddata->addr[startchunk+nchunks] << 32;
                        remote_list[nchunks].size =
                                senddata->len[startchunk+nchunks];
                        length += remote_list[nchunks].size;
                } while (! (senddata->eofmask &
                            (1 << (VETH_EOF_SHIFT + startchunk + nchunks++))));

                /* length == total length of all chunks */
                /* nchunks == # of chunks in this frame */

                if ((length - ETH_HLEN) > VETH_MAX_MTU) {
                        veth_error("Received oversize frame from LPAR %d "
                                        "(length = %d)\n",
                                        cnx->remote_lp, length);
                        continue;
                }

                skb = alloc_skb(length, GFP_ATOMIC);
                if (!skb)
                        continue;

                veth_build_dma_list(local_list, skb->data, length);

                rc = HvCallEvent_dmaBufList(HvLpEvent_Type_VirtualLan,
                                            event->base_event.xSourceLp,
                                            HvLpDma_Direction_RemoteToLocal,
                                            cnx->src_inst,
                                            cnx->dst_inst,
                                            HvLpDma_AddressType_RealAddress,
                                            HvLpDma_AddressType_TceIndex,
                                            iseries_hv_addr(&local_list),
                                            iseries_hv_addr(&remote_list),
                                            length);
                if (rc != HvLpDma_Rc_Good) {
                        dev_kfree_skb_irq(skb);
                        continue;
                }

                vlan = skb->data[9];
                dev = veth_dev[vlan];
                if (! dev) {
                        /*
                         * Some earlier versions of the driver sent
                         * broadcasts down all connections, even to lpars
                         * that weren't on the relevant vlan. So ignore
                         * packets belonging to a vlan we're not on.
                         * We can also be here if we receive packets while
                         * the driver is going down, because then dev is NULL.
                         */
                        dev_kfree_skb_irq(skb);
                        continue;
                }

                port = netdev_priv(dev);
                dest = *((u64 *) skb->data) & 0xFFFFFFFFFFFF0000;

                if ((vlan > HVMAXARCHITECTEDVIRTUALLANS) || !port) {
                        dev_kfree_skb_irq(skb);
                        continue;
                }
                if (! veth_frame_wanted(port, dest)) {
                        dev_kfree_skb_irq(skb);
                        continue;
                }

                skb_put(skb, length);
                skb->protocol = eth_type_trans(skb, dev);
                skb->ip_summed = CHECKSUM_NONE;
                netif_rx(skb);  /* send it up */
                dev->stats.rx_packets++;
                dev->stats.rx_bytes += length;
        } while (startchunk += nchunks, startchunk < VETH_MAX_FRAMES_PER_MSG);

        /* Ack it */
        spin_lock_irqsave(&cnx->lock, flags);
        BUG_ON(cnx->num_pending_acks > VETH_MAX_ACKS_PER_MSG);

        cnx->pending_acks[cnx->num_pending_acks++] =
                event->base_event.xCorrelationToken;

        if ( (cnx->num_pending_acks >= cnx->remote_caps.ack_threshold) ||
             (cnx->num_pending_acks >= VETH_MAX_ACKS_PER_MSG) )
                veth_flush_acks(cnx);

        spin_unlock_irqrestore(&cnx->lock, flags);
}

static void veth_timed_ack(unsigned long ptr)
{
        struct veth_lpar_connection *cnx = (struct veth_lpar_connection *) ptr;
        unsigned long flags;

        /* Ack all the events */
        spin_lock_irqsave(&cnx->lock, flags);
        if (cnx->num_pending_acks > 0)
                veth_flush_acks(cnx);

        /* Reschedule the timer */
        cnx->ack_timer.expires = jiffies + cnx->ack_timeout;
        add_timer(&cnx->ack_timer);
        spin_unlock_irqrestore(&cnx->lock, flags);
}

static int veth_remove(struct vio_dev *vdev)
{
        struct veth_lpar_connection *cnx;
        struct net_device *dev;
        struct veth_port *port;
        int i;

        dev = veth_dev[vdev->unit_address];

        if (! dev)
                return 0;

        port = netdev_priv(dev);

        for (i = 0; i < HVMAXARCHITECTEDLPS; i++) {
                cnx = veth_cnx[i];

                if (cnx && (port->lpar_map & (1 << i))) {
                        /* Drop our reference to connections on our VLAN */
                        kobject_put(&cnx->kobject);
                }
        }

        veth_dev[vdev->unit_address] = NULL;
        kobject_del(&port->kobject);
        kobject_put(&port->kobject);
        unregister_netdev(dev);
        free_netdev(dev);

        return 0;
}

static int veth_probe(struct vio_dev *vdev, const struct vio_device_id *id)
{
        int i = vdev->unit_address;
        struct net_device *dev;
        struct veth_port *port;

        dev = veth_probe_one(i, vdev);
        if (dev == NULL) {
                veth_remove(vdev);
                return 1;
        }
        veth_dev[i] = dev;

        port = (struct veth_port*)netdev_priv(dev);

        /* Start the state machine on each connection on this vlan. If we're
         * the first dev to do so this will commence link negotiation */
        for (i = 0; i < HVMAXARCHITECTEDLPS; i++) {
                struct veth_lpar_connection *cnx;

                if (! (port->lpar_map & (1 << i)))
                        continue;

                cnx = veth_cnx[i];
                if (!cnx)
                        continue;

                kobject_get(&cnx->kobject);
                veth_kick_statemachine(cnx);
        }

        return 0;
}

/**
 * veth_device_table: Used by vio.c to match devices that we
 * support.
 */
static struct vio_device_id veth_device_table[] __devinitdata = {
        { "network", "IBM,iSeries-l-lan" },
        { "", "" }
};
MODULE_DEVICE_TABLE(vio, veth_device_table);

static struct vio_driver veth_driver = {
        .id_table = veth_device_table,
        .probe = veth_probe,
        .remove = veth_remove,
        .driver = {
                .name = DRV_NAME,
                .owner = THIS_MODULE,
        }
};

/*
 * Module initialization/cleanup
 */

static void __exit veth_module_cleanup(void)
{
        int i;
        struct veth_lpar_connection *cnx;

        /* Disconnect our "irq" to stop events coming from the Hypervisor. */
        HvLpEvent_unregisterHandler(HvLpEvent_Type_VirtualLan);

        /* Make sure any work queued from Hypervisor callbacks is finished. */
        flush_scheduled_work();

        for (i = 0; i < HVMAXARCHITECTEDLPS; ++i) {
                cnx = veth_cnx[i];

                if (!cnx)
                        continue;

                /* Remove the connection from sysfs */
                kobject_del(&cnx->kobject);
                /* Drop the driver's reference to the connection */
                kobject_put(&cnx->kobject);
        }

        /* Unregister the driver, which will close all the netdevs and stop
         * the connections when they're no longer referenced. */
        vio_unregister_driver(&veth_driver);
}
module_exit(veth_module_cleanup);

static int __init veth_module_init(void)
{
        int i;
        int rc;

        if (!firmware_has_feature(FW_FEATURE_ISERIES))
                return -ENODEV;

        this_lp = HvLpConfig_getLpIndex_outline();

        for (i = 0; i < HVMAXARCHITECTEDLPS; ++i) {
                rc = veth_init_connection(i);
                if (rc != 0)
                        goto error;
        }

        HvLpEvent_registerHandler(HvLpEvent_Type_VirtualLan,
                                  &veth_handle_event);

        rc = vio_register_driver(&veth_driver);
        if (rc != 0)
                goto error;

        for (i = 0; i < HVMAXARCHITECTEDLPS; ++i) {
                struct kobject *kobj;

                if (!veth_cnx[i])
                        continue;

                kobj = &veth_cnx[i]->kobject;
                /* If the add failes, complain but otherwise continue */
                if (0 != driver_add_kobj(&veth_driver.driver, kobj,
                                        "cnx%.2d", veth_cnx[i]->remote_lp))
                        veth_error("cnx %d: Failed adding to sysfs.\n", i);
        }

        return 0;

error:
        for (i = 0; i < HVMAXARCHITECTEDLPS; ++i) {
                veth_destroy_connection(veth_cnx[i]);
        }

        return rc;
}
module_init(veth_module_init);