/*
 * Copyright (c) 2006, 2007, 2008 QLogic Corporation. All rights reserved.
 * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/err.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include "ipath_verbs.h"
#include "ipath_kernel.h"

#define BITS_PER_PAGE           (PAGE_SIZE*BITS_PER_BYTE)
#define BITS_PER_PAGE_MASK      (BITS_PER_PAGE-1)
#define mk_qpn(qpt, map, off)   (((map) - (qpt)->map) * BITS_PER_PAGE + \
                                 (off))
#define find_next_offset(map, off) find_next_zero_bit((map)->page, \
                                                      BITS_PER_PAGE, off)

/*
 * Convert the AETH credit code into the number of credits.
 */
static u32 credit_table[31] = {
        0,                      /* 0 */
        1,                      /* 1 */
        2,                      /* 2 */
        3,                      /* 3 */
        4,                      /* 4 */
        6,                      /* 5 */
        8,                      /* 6 */
        12,                     /* 7 */
        16,                     /* 8 */
        24,                     /* 9 */
        32,                     /* A */
        48,                     /* B */
        64,                     /* C */
        96,                     /* D */
        128,                    /* E */
        192,                    /* F */
        256,                    /* 10 */
        384,                    /* 11 */
        512,                    /* 12 */
        768,                    /* 13 */
        1024,                   /* 14 */
        1536,                   /* 15 */
        2048,                   /* 16 */
        3072,                   /* 17 */
        4096,                   /* 18 */
        6144,                   /* 19 */
        8192,                   /* 1A */
        12288,                  /* 1B */
        16384,                  /* 1C */
        24576,                  /* 1D */
        32768                   /* 1E */
};


static void get_map_page(struct ipath_qp_table *qpt, struct qpn_map *map)
{
        unsigned long page = get_zeroed_page(GFP_KERNEL);
        unsigned long flags;

        /*
         * Free the page if someone raced with us installing it.
         */

        spin_lock_irqsave(&qpt->lock, flags);
        if (map->page)
                free_page(page);
        else
                map->page = (void *)page;
        spin_unlock_irqrestore(&qpt->lock, flags);
}


static int alloc_qpn(struct ipath_qp_table *qpt, enum ib_qp_type type)
{
        u32 i, offset, max_scan, qpn;
        struct qpn_map *map;
        u32 ret = -1;

        if (type == IB_QPT_SMI)
                ret = 0;
        else if (type == IB_QPT_GSI)
                ret = 1;

        if (ret != -1) {
                map = &qpt->map[0];
                if (unlikely(!map->page)) {
                        get_map_page(qpt, map);
                        if (unlikely(!map->page)) {
                                ret = -ENOMEM;
                                goto bail;
                        }
                }
                if (!test_and_set_bit(ret, map->page))
                        atomic_dec(&map->n_free);
                else
                        ret = -EBUSY;
                goto bail;
        }

        qpn = qpt->last + 1;
        if (qpn >= QPN_MAX)
                qpn = 2;
        offset = qpn & BITS_PER_PAGE_MASK;
        map = &qpt->map[qpn / BITS_PER_PAGE];
        max_scan = qpt->nmaps - !offset;
        for (i = 0;;) {
                if (unlikely(!map->page)) {
                        get_map_page(qpt, map);
                        if (unlikely(!map->page))
                                break;
                }
                if (likely(atomic_read(&map->n_free))) {
                        do {
                                if (!test_and_set_bit(offset, map->page)) {
                                        atomic_dec(&map->n_free);
                                        qpt->last = qpn;
                                        ret = qpn;
                                        goto bail;
                                }
                                offset = find_next_offset(map, offset);
                                qpn = mk_qpn(qpt, map, offset);
                                /*
                                 * This test differs from alloc_pidmap().
                                 * If find_next_offset() does find a zero
                                 * bit, we don't need to check for QPN
                                 * wrapping around past our starting QPN.
                                 * We just need to be sure we don't loop
                                 * forever.
                                 */
                        } while (offset < BITS_PER_PAGE && qpn < QPN_MAX);
                }
                /*
                 * In order to keep the number of pages allocated to a
                 * minimum, we scan the all existing pages before increasing
                 * the size of the bitmap table.
                 */
                if (++i > max_scan) {
                        if (qpt->nmaps == QPNMAP_ENTRIES)
                                break;
                        map = &qpt->map[qpt->nmaps++];
                        offset = 0;
                } else if (map < &qpt->map[qpt->nmaps]) {
                        ++map;
                        offset = 0;
                } else {
                        map = &qpt->map[0];
                        offset = 2;
                }
                qpn = mk_qpn(qpt, map, offset);
        }

        ret = -ENOMEM;

bail:
        return ret;
}

static void free_qpn(struct ipath_qp_table *qpt, u32 qpn)
{
        struct qpn_map *map;

        map = qpt->map + qpn / BITS_PER_PAGE;
        if (map->page)
                clear_bit(qpn & BITS_PER_PAGE_MASK, map->page);
        atomic_inc(&map->n_free);
}

/**
 * ipath_alloc_qpn - allocate a QP number
 * @qpt: the QP table
 * @qp: the QP
 * @type: the QP type (IB_QPT_SMI and IB_QPT_GSI are special)
 *
 * Allocate the next available QPN and put the QP into the hash table.
 * The hash table holds a reference to the QP.
 */
static int ipath_alloc_qpn(struct ipath_qp_table *qpt, struct ipath_qp *qp,
                           enum ib_qp_type type)
{
        unsigned long flags;
        int ret;

        ret = alloc_qpn(qpt, type);
        if (ret < 0)
                goto bail;
        qp->ibqp.qp_num = ret;

        /* Add the QP to the hash table. */
        spin_lock_irqsave(&qpt->lock, flags);

        ret %= qpt->max;
        qp->next = qpt->table[ret];
        qpt->table[ret] = qp;
        atomic_inc(&qp->refcount);

        spin_unlock_irqrestore(&qpt->lock, flags);
        ret = 0;

bail:
        return ret;
}

/**
 * ipath_free_qp - remove a QP from the QP table
 * @qpt: the QP table
 * @qp: the QP to remove
 *
 * Remove the QP from the table so it can't be found asynchronously by
 * the receive interrupt routine.
 */
static void ipath_free_qp(struct ipath_qp_table *qpt, struct ipath_qp *qp)
{
        struct ipath_qp *q, **qpp;
        unsigned long flags;

        spin_lock_irqsave(&qpt->lock, flags);

        /* Remove QP from the hash table. */
        qpp = &qpt->table[qp->ibqp.qp_num % qpt->max];
        for (; (q = *qpp) != NULL; qpp = &q->next) {
                if (q == qp) {
                        *qpp = qp->next;
                        qp->next = NULL;
                        atomic_dec(&qp->refcount);
                        break;
                }
        }

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

/**
 * ipath_free_all_qps - check for QPs still in use
 * @qpt: the QP table to empty
 *
 * There should not be any QPs still in use.
 * Free memory for table.
 */
unsigned ipath_free_all_qps(struct ipath_qp_table *qpt)
{
        unsigned long flags;
        struct ipath_qp *qp;
        u32 n, qp_inuse = 0;

        spin_lock_irqsave(&qpt->lock, flags);
        for (n = 0; n < qpt->max; n++) {
                qp = qpt->table[n];
                qpt->table[n] = NULL;

                for (; qp; qp = qp->next)
                        qp_inuse++;
        }
        spin_unlock_irqrestore(&qpt->lock, flags);

        for (n = 0; n < ARRAY_SIZE(qpt->map); n++)
                if (qpt->map[n].page)
                        free_page((unsigned long) qpt->map[n].page);
        return qp_inuse;
}

/**
 * ipath_lookup_qpn - return the QP with the given QPN
 * @qpt: the QP table
 * @qpn: the QP number to look up
 *
 * The caller is responsible for decrementing the QP reference count
 * when done.
 */
struct ipath_qp *ipath_lookup_qpn(struct ipath_qp_table *qpt, u32 qpn)
{
        unsigned long flags;
        struct ipath_qp *qp;

        spin_lock_irqsave(&qpt->lock, flags);

        for (qp = qpt->table[qpn % qpt->max]; qp; qp = qp->next) {
                if (qp->ibqp.qp_num == qpn) {
                        atomic_inc(&qp->refcount);
                        break;
                }
        }

        spin_unlock_irqrestore(&qpt->lock, flags);
        return qp;
}

/**
 * ipath_reset_qp - initialize the QP state to the reset state
 * @qp: the QP to reset
 * @type: the QP type
 */
static void ipath_reset_qp(struct ipath_qp *qp, enum ib_qp_type type)
{
        qp->remote_qpn = 0;
        qp->qkey = 0;
        qp->qp_access_flags = 0;
        atomic_set(&qp->s_dma_busy, 0);
        qp->s_flags &= IPATH_S_SIGNAL_REQ_WR;
        qp->s_hdrwords = 0;
        qp->s_wqe = NULL;
        qp->s_pkt_delay = 0;
        qp->s_draining = 0;
        qp->s_psn = 0;
        qp->r_psn = 0;
        qp->r_msn = 0;
        if (type == IB_QPT_RC) {
                qp->s_state = IB_OPCODE_RC_SEND_LAST;
                qp->r_state = IB_OPCODE_RC_SEND_LAST;
        } else {
                qp->s_state = IB_OPCODE_UC_SEND_LAST;
                qp->r_state = IB_OPCODE_UC_SEND_LAST;
        }
        qp->s_ack_state = IB_OPCODE_RC_ACKNOWLEDGE;
        qp->r_nak_state = 0;
        qp->r_aflags = 0;
        qp->r_flags = 0;
        qp->s_rnr_timeout = 0;
        qp->s_head = 0;
        qp->s_tail = 0;
        qp->s_cur = 0;
        qp->s_last = 0;
        qp->s_ssn = 1;
        qp->s_lsn = 0;
        memset(qp->s_ack_queue, 0, sizeof(qp->s_ack_queue));
        qp->r_head_ack_queue = 0;
        qp->s_tail_ack_queue = 0;
        qp->s_num_rd_atomic = 0;
        if (qp->r_rq.wq) {
                qp->r_rq.wq->head = 0;
                qp->r_rq.wq->tail = 0;
        }
}

/**
 * ipath_error_qp - put a QP into the error state
 * @qp: the QP to put into the error state
 * @err: the receive completion error to signal if a RWQE is active
 *
 * Flushes both send and receive work queues.
 * Returns true if last WQE event should be generated.
 * The QP s_lock should be held and interrupts disabled.
 * If we are already in error state, just return.
 */

int ipath_error_qp(struct ipath_qp *qp, enum ib_wc_status err)
{
        struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
        struct ib_wc wc;
        int ret = 0;

        if (qp->state == IB_QPS_ERR)
                goto bail;

        qp->state = IB_QPS_ERR;

        spin_lock(&dev->pending_lock);
        if (!list_empty(&qp->timerwait))
                list_del_init(&qp->timerwait);
        if (!list_empty(&qp->piowait))
                list_del_init(&qp->piowait);
        spin_unlock(&dev->pending_lock);

        /* Schedule the sending tasklet to drain the send work queue. */
        if (qp->s_last != qp->s_head)
                ipath_schedule_send(qp);

        memset(&wc, 0, sizeof(wc));
        wc.qp = &qp->ibqp;
        wc.opcode = IB_WC_RECV;

        if (test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags)) {
                wc.wr_id = qp->r_wr_id;
                wc.status = err;
                ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
        }
        wc.status = IB_WC_WR_FLUSH_ERR;

        if (qp->r_rq.wq) {
                struct ipath_rwq *wq;
                u32 head;
                u32 tail;

                spin_lock(&qp->r_rq.lock);

                /* sanity check pointers before trusting them */
                wq = qp->r_rq.wq;
                head = wq->head;
                if (head >= qp->r_rq.size)
                        head = 0;
                tail = wq->tail;
                if (tail >= qp->r_rq.size)
                        tail = 0;
                while (tail != head) {
                        wc.wr_id = get_rwqe_ptr(&qp->r_rq, tail)->wr_id;
                        if (++tail >= qp->r_rq.size)
                                tail = 0;
                        ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
                }
                wq->tail = tail;

                spin_unlock(&qp->r_rq.lock);
        } else if (qp->ibqp.event_handler)
                ret = 1;

bail:
        return ret;
}

/**
 * ipath_modify_qp - modify the attributes of a queue pair
 * @ibqp: the queue pair who's attributes we're modifying
 * @attr: the new attributes
 * @attr_mask: the mask of attributes to modify
 * @udata: user data for ipathverbs.so
 *
 * Returns 0 on success, otherwise returns an errno.
 */
int ipath_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
                    int attr_mask, struct ib_udata *udata)
{
        struct ipath_ibdev *dev = to_idev(ibqp->device);
        struct ipath_qp *qp = to_iqp(ibqp);
        enum ib_qp_state cur_state, new_state;
        int lastwqe = 0;
        int ret;

        spin_lock_irq(&qp->s_lock);

        cur_state = attr_mask & IB_QP_CUR_STATE ?
                attr->cur_qp_state : qp->state;
        new_state = attr_mask & IB_QP_STATE ? attr->qp_state : cur_state;

        if (!ib_modify_qp_is_ok(cur_state, new_state, ibqp->qp_type,
                                attr_mask))
                goto inval;

        if (attr_mask & IB_QP_AV) {
                if (attr->ah_attr.dlid == 0 ||
                    attr->ah_attr.dlid >= IPATH_MULTICAST_LID_BASE)
                        goto inval;

                if ((attr->ah_attr.ah_flags & IB_AH_GRH) &&
                    (attr->ah_attr.grh.sgid_index > 1))
                        goto inval;
        }

        if (attr_mask & IB_QP_PKEY_INDEX)
                if (attr->pkey_index >= ipath_get_npkeys(dev->dd))
                        goto inval;

        if (attr_mask & IB_QP_MIN_RNR_TIMER)
                if (attr->min_rnr_timer > 31)
                        goto inval;

        if (attr_mask & IB_QP_PORT)
                if (attr->port_num == 0 ||
                    attr->port_num > ibqp->device->phys_port_cnt)
                        goto inval;

        /*
         * don't allow invalid Path MTU values or greater than 2048
         * unless we are configured for a 4KB MTU
         */
        if ((attr_mask & IB_QP_PATH_MTU) &&
                (ib_mtu_enum_to_int(attr->path_mtu) == -1 ||
                (attr->path_mtu > IB_MTU_2048 && !ipath_mtu4096)))
                goto inval;

        if (attr_mask & IB_QP_PATH_MIG_STATE)
                if (attr->path_mig_state != IB_MIG_MIGRATED &&
                    attr->path_mig_state != IB_MIG_REARM)
                        goto inval;

        if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
                if (attr->max_dest_rd_atomic > IPATH_MAX_RDMA_ATOMIC)
                        goto inval;

        switch (new_state) {
        case IB_QPS_RESET:
                if (qp->state != IB_QPS_RESET) {
                        qp->state = IB_QPS_RESET;
                        spin_lock(&dev->pending_lock);
                        if (!list_empty(&qp->timerwait))
                                list_del_init(&qp->timerwait);
                        if (!list_empty(&qp->piowait))
                                list_del_init(&qp->piowait);
                        spin_unlock(&dev->pending_lock);
                        qp->s_flags &= ~IPATH_S_ANY_WAIT;
                        spin_unlock_irq(&qp->s_lock);
                        /* Stop the sending tasklet */
                        tasklet_kill(&qp->s_task);
                        wait_event(qp->wait_dma, !atomic_read(&qp->s_dma_busy));
                        spin_lock_irq(&qp->s_lock);
                }
                ipath_reset_qp(qp, ibqp->qp_type);
                break;

        case IB_QPS_SQD:
                qp->s_draining = qp->s_last != qp->s_cur;
                qp->state = new_state;
                break;

        case IB_QPS_SQE:
                if (qp->ibqp.qp_type == IB_QPT_RC)
                        goto inval;
                qp->state = new_state;
                break;

        case IB_QPS_ERR:
                lastwqe = ipath_error_qp(qp, IB_WC_WR_FLUSH_ERR);
                break;

        default:
                qp->state = new_state;
                break;
        }

        if (attr_mask & IB_QP_PKEY_INDEX)
                qp->s_pkey_index = attr->pkey_index;

        if (attr_mask & IB_QP_DEST_QPN)
                qp->remote_qpn = attr->dest_qp_num;

        if (attr_mask & IB_QP_SQ_PSN) {
                qp->s_psn = qp->s_next_psn = attr->sq_psn;
                qp->s_last_psn = qp->s_next_psn - 1;
        }

        if (attr_mask & IB_QP_RQ_PSN)
                qp->r_psn = attr->rq_psn;

        if (attr_mask & IB_QP_ACCESS_FLAGS)
                qp->qp_access_flags = attr->qp_access_flags;

        if (attr_mask & IB_QP_AV) {
                qp->remote_ah_attr = attr->ah_attr;
                qp->s_dmult = ipath_ib_rate_to_mult(attr->ah_attr.static_rate);
        }

        if (attr_mask & IB_QP_PATH_MTU)
                qp->path_mtu = attr->path_mtu;

        if (attr_mask & IB_QP_RETRY_CNT)
                qp->s_retry = qp->s_retry_cnt = attr->retry_cnt;

        if (attr_mask & IB_QP_RNR_RETRY) {
                qp->s_rnr_retry = attr->rnr_retry;
                if (qp->s_rnr_retry > 7)
                        qp->s_rnr_retry = 7;
                qp->s_rnr_retry_cnt = qp->s_rnr_retry;
        }

        if (attr_mask & IB_QP_MIN_RNR_TIMER)
                qp->r_min_rnr_timer = attr->min_rnr_timer;

        if (attr_mask & IB_QP_TIMEOUT)
                qp->timeout = attr->timeout;

        if (attr_mask & IB_QP_QKEY)
                qp->qkey = attr->qkey;

        if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
                qp->r_max_rd_atomic = attr->max_dest_rd_atomic;

        if (attr_mask & IB_QP_MAX_QP_RD_ATOMIC)
                qp->s_max_rd_atomic = attr->max_rd_atomic;

        spin_unlock_irq(&qp->s_lock);

        if (lastwqe) {
                struct ib_event ev;

                ev.device = qp->ibqp.device;
                ev.element.qp = &qp->ibqp;
                ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
                qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
        }
        ret = 0;
        goto bail;

inval:
        spin_unlock_irq(&qp->s_lock);
        ret = -EINVAL;

bail:
        return ret;
}

int ipath_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
                   int attr_mask, struct ib_qp_init_attr *init_attr)
{
        struct ipath_qp *qp = to_iqp(ibqp);

        attr->qp_state = qp->state;
        attr->cur_qp_state = attr->qp_state;
        attr->path_mtu = qp->path_mtu;
        attr->path_mig_state = 0;
        attr->qkey = qp->qkey;
        attr->rq_psn = qp->r_psn;
        attr->sq_psn = qp->s_next_psn;
        attr->dest_qp_num = qp->remote_qpn;
        attr->qp_access_flags = qp->qp_access_flags;
        attr->cap.max_send_wr = qp->s_size - 1;
        attr->cap.max_recv_wr = qp->ibqp.srq ? 0 : qp->r_rq.size - 1;
        attr->cap.max_send_sge = qp->s_max_sge;
        attr->cap.max_recv_sge = qp->r_rq.max_sge;
        attr->cap.max_inline_data = 0;
        attr->ah_attr = qp->remote_ah_attr;
        memset(&attr->alt_ah_attr, 0, sizeof(attr->alt_ah_attr));
        attr->pkey_index = qp->s_pkey_index;
        attr->alt_pkey_index = 0;
        attr->en_sqd_async_notify = 0;
        attr->sq_draining = qp->s_draining;
        attr->max_rd_atomic = qp->s_max_rd_atomic;
        attr->max_dest_rd_atomic = qp->r_max_rd_atomic;
        attr->min_rnr_timer = qp->r_min_rnr_timer;
        attr->port_num = 1;
        attr->timeout = qp->timeout;
        attr->retry_cnt = qp->s_retry_cnt;
        attr->rnr_retry = qp->s_rnr_retry_cnt;
        attr->alt_port_num = 0;
        attr->alt_timeout = 0;

        init_attr->event_handler = qp->ibqp.event_handler;
        init_attr->qp_context = qp->ibqp.qp_context;
        init_attr->send_cq = qp->ibqp.send_cq;
        init_attr->recv_cq = qp->ibqp.recv_cq;
        init_attr->srq = qp->ibqp.srq;
        init_attr->cap = attr->cap;
        if (qp->s_flags & IPATH_S_SIGNAL_REQ_WR)
                init_attr->sq_sig_type = IB_SIGNAL_REQ_WR;
        else
                init_attr->sq_sig_type = IB_SIGNAL_ALL_WR;
        init_attr->qp_type = qp->ibqp.qp_type;
        init_attr->port_num = 1;
        return 0;
}

/**
 * ipath_compute_aeth - compute the AETH (syndrome + MSN)
 * @qp: the queue pair to compute the AETH for
 *
 * Returns the AETH.
 */
__be32 ipath_compute_aeth(struct ipath_qp *qp)
{
        u32 aeth = qp->r_msn & IPATH_MSN_MASK;

        if (qp->ibqp.srq) {
                /*
                 * Shared receive queues don't generate credits.
                 * Set the credit field to the invalid value.
                 */
                aeth |= IPATH_AETH_CREDIT_INVAL << IPATH_AETH_CREDIT_SHIFT;
        } else {
                u32 min, max, x;
                u32 credits;
                struct ipath_rwq *wq = qp->r_rq.wq;
                u32 head;
                u32 tail;

                /* sanity check pointers before trusting them */
                head = wq->head;
                if (head >= qp->r_rq.size)
                        head = 0;
                tail = wq->tail;
                if (tail >= qp->r_rq.size)
                        tail = 0;
                /*
                 * Compute the number of credits available (RWQEs).
                 * XXX Not holding the r_rq.lock here so there is a small
                 * chance that the pair of reads are not atomic.
                 */
                credits = head - tail;
                if ((int)credits < 0)
                        credits += qp->r_rq.size;
                /*
                 * Binary search the credit table to find the code to
                 * use.
                 */
                min = 0;
                max = 31;
                for (;;) {
                        x = (min + max) / 2;
                        if (credit_table[x] == credits)
                                break;
                        if (credit_table[x] > credits)
                                max = x;
                        else if (min == x)
                                break;
                        else
                                min = x;
                }
                aeth |= x << IPATH_AETH_CREDIT_SHIFT;
        }
        return cpu_to_be32(aeth);
}

/**
 * ipath_create_qp - create a queue pair for a device
 * @ibpd: the protection domain who's device we create the queue pair for
 * @init_attr: the attributes of the queue pair
 * @udata: unused by InfiniPath
 *
 * Returns the queue pair on success, otherwise returns an errno.
 *
 * Called by the ib_create_qp() core verbs function.
 */
struct ib_qp *ipath_create_qp(struct ib_pd *ibpd,
                              struct ib_qp_init_attr *init_attr,
                              struct ib_udata *udata)
{
        struct ipath_qp *qp;
        int err;
        struct ipath_swqe *swq = NULL;
        struct ipath_ibdev *dev;
        size_t sz;
        size_t sg_list_sz;
        struct ib_qp *ret;

        if (init_attr->create_flags) {
                ret = ERR_PTR(-EINVAL);
                goto bail;
        }

        if (init_attr->cap.max_send_sge > ib_ipath_max_sges ||
            init_attr->cap.max_send_wr > ib_ipath_max_qp_wrs) {
                ret = ERR_PTR(-EINVAL);
                goto bail;
        }

        /* Check receive queue parameters if no SRQ is specified. */
        if (!init_attr->srq) {
                if (init_attr->cap.max_recv_sge > ib_ipath_max_sges ||
                    init_attr->cap.max_recv_wr > ib_ipath_max_qp_wrs) {
                        ret = ERR_PTR(-EINVAL);
                        goto bail;
                }
                if (init_attr->cap.max_send_sge +
                    init_attr->cap.max_send_wr +
                    init_attr->cap.max_recv_sge +
                    init_attr->cap.max_recv_wr == 0) {
                        ret = ERR_PTR(-EINVAL);
                        goto bail;
                }
        }

        switch (init_attr->qp_type) {
        case IB_QPT_UC:
        case IB_QPT_RC:
        case IB_QPT_UD:
        case IB_QPT_SMI:
        case IB_QPT_GSI:
                sz = sizeof(struct ipath_sge) *
                        init_attr->cap.max_send_sge +
                        sizeof(struct ipath_swqe);
                swq = vmalloc((init_attr->cap.max_send_wr + 1) * sz);
                if (swq == NULL) {
                        ret = ERR_PTR(-ENOMEM);
                        goto bail;
                }
                sz = sizeof(*qp);
                sg_list_sz = 0;
                if (init_attr->srq) {
                        struct ipath_srq *srq = to_isrq(init_attr->srq);

                        if (srq->rq.max_sge > 1)
                                sg_list_sz = sizeof(*qp->r_sg_list) *
                                        (srq->rq.max_sge - 1);
                } else if (init_attr->cap.max_recv_sge > 1)
                        sg_list_sz = sizeof(*qp->r_sg_list) *
                                (init_attr->cap.max_recv_sge - 1);
                qp = kmalloc(sz + sg_list_sz, GFP_KERNEL);
                if (!qp) {
                        ret = ERR_PTR(-ENOMEM);
                        goto bail_swq;
                }
                if (sg_list_sz && (init_attr->qp_type == IB_QPT_UD ||
                    init_attr->qp_type == IB_QPT_SMI ||
                    init_attr->qp_type == IB_QPT_GSI)) {
                        qp->r_ud_sg_list = kmalloc(sg_list_sz, GFP_KERNEL);
                        if (!qp->r_ud_sg_list) {
                                ret = ERR_PTR(-ENOMEM);
                                goto bail_qp;
                        }
                } else
                        qp->r_ud_sg_list = NULL;
                if (init_attr->srq) {
                        sz = 0;
                        qp->r_rq.size = 0;
                        qp->r_rq.max_sge = 0;
                        qp->r_rq.wq = NULL;
                        init_attr->cap.max_recv_wr = 0;
                        init_attr->cap.max_recv_sge = 0;
                } else {
                        qp->r_rq.size = init_attr->cap.max_recv_wr + 1;
                        qp->r_rq.max_sge = init_attr->cap.max_recv_sge;
                        sz = (sizeof(struct ib_sge) * qp->r_rq.max_sge) +
                                sizeof(struct ipath_rwqe);
                        qp->r_rq.wq = vmalloc_user(sizeof(struct ipath_rwq) +
                                              qp->r_rq.size * sz);
                        if (!qp->r_rq.wq) {
                                ret = ERR_PTR(-ENOMEM);
                                goto bail_sg_list;
                        }
                }

                /*
                 * ib_create_qp() will initialize qp->ibqp
                 * except for qp->ibqp.qp_num.
                 */
                spin_lock_init(&qp->s_lock);
                spin_lock_init(&qp->r_rq.lock);
                atomic_set(&qp->refcount, 0);
                init_waitqueue_head(&qp->wait);
                init_waitqueue_head(&qp->wait_dma);
                tasklet_init(&qp->s_task, ipath_do_send, (unsigned long)qp);
                INIT_LIST_HEAD(&qp->piowait);
                INIT_LIST_HEAD(&qp->timerwait);
                qp->state = IB_QPS_RESET;
                qp->s_wq = swq;
                qp->s_size = init_attr->cap.max_send_wr + 1;
                qp->s_max_sge = init_attr->cap.max_send_sge;
                if (init_attr->sq_sig_type == IB_SIGNAL_REQ_WR)
                        qp->s_flags = IPATH_S_SIGNAL_REQ_WR;
                else
                        qp->s_flags = 0;
                dev = to_idev(ibpd->device);
                err = ipath_alloc_qpn(&dev->qp_table, qp,
                                      init_attr->qp_type);
                if (err) {
                        ret = ERR_PTR(err);
                        vfree(qp->r_rq.wq);
                        goto bail_sg_list;
                }
                qp->ip = NULL;
                qp->s_tx = NULL;
                ipath_reset_qp(qp, init_attr->qp_type);
                break;

        default:
                /* Don't support raw QPs */
                ret = ERR_PTR(-ENOSYS);
                goto bail;
        }

        init_attr->cap.max_inline_data = 0;

        /*
         * Return the address of the RWQ as the offset to mmap.
         * See ipath_mmap() for details.
         */
        if (udata && udata->outlen >= sizeof(__u64)) {
                if (!qp->r_rq.wq) {
                        __u64 offset = 0;

                        err = ib_copy_to_udata(udata, &offset,
                                               sizeof(offset));
                        if (err) {
                                ret = ERR_PTR(err);
                                goto bail_ip;
                        }
                } else {
                        u32 s = sizeof(struct ipath_rwq) +
                                qp->r_rq.size * sz;

                        qp->ip =
                            ipath_create_mmap_info(dev, s,
                                                   ibpd->uobject->context,
                                                   qp->r_rq.wq);
                        if (!qp->ip) {
                                ret = ERR_PTR(-ENOMEM);
                                goto bail_ip;
                        }

                        err = ib_copy_to_udata(udata, &(qp->ip->offset),
                                               sizeof(qp->ip->offset));
                        if (err) {
                                ret = ERR_PTR(err);
                                goto bail_ip;
                        }
                }
        }

        spin_lock(&dev->n_qps_lock);
        if (dev->n_qps_allocated == ib_ipath_max_qps) {
                spin_unlock(&dev->n_qps_lock);
                ret = ERR_PTR(-ENOMEM);
                goto bail_ip;
        }

        dev->n_qps_allocated++;
        spin_unlock(&dev->n_qps_lock);

        if (qp->ip) {
                spin_lock_irq(&dev->pending_lock);
                list_add(&qp->ip->pending_mmaps, &dev->pending_mmaps);
                spin_unlock_irq(&dev->pending_lock);
        }

        ret = &qp->ibqp;
        goto bail;

bail_ip:
        if (qp->ip)
                kref_put(&qp->ip->ref, ipath_release_mmap_info);
        else
                vfree(qp->r_rq.wq);
        ipath_free_qp(&dev->qp_table, qp);
        free_qpn(&dev->qp_table, qp->ibqp.qp_num);
bail_sg_list:
        kfree(qp->r_ud_sg_list);
bail_qp:
        kfree(qp);
bail_swq:
        vfree(swq);
bail:
        return ret;
}

/**
 * ipath_destroy_qp - destroy a queue pair
 * @ibqp: the queue pair to destroy
 *
 * Returns 0 on success.
 *
 * Note that this can be called while the QP is actively sending or
 * receiving!
 */
int ipath_destroy_qp(struct ib_qp *ibqp)
{
        struct ipath_qp *qp = to_iqp(ibqp);
        struct ipath_ibdev *dev = to_idev(ibqp->device);

        /* Make sure HW and driver activity is stopped. */
        spin_lock_irq(&qp->s_lock);
        if (qp->state != IB_QPS_RESET) {
                qp->state = IB_QPS_RESET;
                spin_lock(&dev->pending_lock);
                if (!list_empty(&qp->timerwait))
                        list_del_init(&qp->timerwait);
                if (!list_empty(&qp->piowait))
                        list_del_init(&qp->piowait);
                spin_unlock(&dev->pending_lock);
                qp->s_flags &= ~IPATH_S_ANY_WAIT;
                spin_unlock_irq(&qp->s_lock);
                /* Stop the sending tasklet */
                tasklet_kill(&qp->s_task);
                wait_event(qp->wait_dma, !atomic_read(&qp->s_dma_busy));
        } else
                spin_unlock_irq(&qp->s_lock);

        ipath_free_qp(&dev->qp_table, qp);

        if (qp->s_tx) {
                atomic_dec(&qp->refcount);
                if (qp->s_tx->txreq.flags & IPATH_SDMA_TXREQ_F_FREEBUF)
                        kfree(qp->s_tx->txreq.map_addr);
                spin_lock_irq(&dev->pending_lock);
                list_add(&qp->s_tx->txreq.list, &dev->txreq_free);
                spin_unlock_irq(&dev->pending_lock);
                qp->s_tx = NULL;
        }

        wait_event(qp->wait, !atomic_read(&qp->refcount));

        /* all user's cleaned up, mark it available */
        free_qpn(&dev->qp_table, qp->ibqp.qp_num);

        spin_lock(&dev->n_qps_lock);
        dev->n_qps_allocated--;
        spin_unlock(&dev->n_qps_lock);

        if (qp->ip)
                kref_put(&qp->ip->ref, ipath_release_mmap_info);
        else
                vfree(qp->r_rq.wq);
        kfree(qp->r_ud_sg_list);
        vfree(qp->s_wq);
        kfree(qp);
        return 0;
}

/**
 * ipath_init_qp_table - initialize the QP table for a device
 * @idev: the device who's QP table we're initializing
 * @size: the size of the QP table
 *
 * Returns 0 on success, otherwise returns an errno.
 */
int ipath_init_qp_table(struct ipath_ibdev *idev, int size)
{
        int i;
        int ret;

        idev->qp_table.last = 1;        /* QPN 0 and 1 are special. */
        idev->qp_table.max = size;
        idev->qp_table.nmaps = 1;
        idev->qp_table.table = kzalloc(size * sizeof(*idev->qp_table.table),
                                       GFP_KERNEL);
        if (idev->qp_table.table == NULL) {
                ret = -ENOMEM;
                goto bail;
        }

        for (i = 0; i < ARRAY_SIZE(idev->qp_table.map); i++) {
                atomic_set(&idev->qp_table.map[i].n_free, BITS_PER_PAGE);
                idev->qp_table.map[i].page = NULL;
        }

        ret = 0;

bail:
        return ret;
}

/**
 * ipath_get_credit - flush the send work queue of a QP
 * @qp: the qp who's send work queue to flush
 * @aeth: the Acknowledge Extended Transport Header
 *
 * The QP s_lock should be held.
 */
void ipath_get_credit(struct ipath_qp *qp, u32 aeth)
{
        u32 credit = (aeth >> IPATH_AETH_CREDIT_SHIFT) & IPATH_AETH_CREDIT_MASK;

        /*
         * If the credit is invalid, we can send
         * as many packets as we like.  Otherwise, we have to
         * honor the credit field.
         */
        if (credit == IPATH_AETH_CREDIT_INVAL)
                qp->s_lsn = (u32) -1;
        else if (qp->s_lsn != (u32) -1) {
                /* Compute new LSN (i.e., MSN + credit) */
                credit = (aeth + credit_table[credit]) & IPATH_MSN_MASK;
                if (ipath_cmp24(credit, qp->s_lsn) > 0)
                        qp->s_lsn = credit;
        }

        /* Restart sending if it was blocked due to lack of credits. */
        if ((qp->s_flags & IPATH_S_WAIT_SSN_CREDIT) &&
            qp->s_cur != qp->s_head &&
            (qp->s_lsn == (u32) -1 ||
             ipath_cmp24(get_swqe_ptr(qp, qp->s_cur)->ssn,
                         qp->s_lsn + 1) <= 0))
                ipath_schedule_send(qp);
}