/*
 * Copyright (c) 2013 Intel Corporation.  All rights reserved.
 * Copyright (c) 2006, 2007, 2008, 2010 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/slab.h>
#include <linux/vmalloc.h>
#include <linux/kthread.h>

#include "qib_verbs.h"
#include "qib.h"

/**
 * qib_cq_enter - add a new entry to the completion queue
 * @cq: completion queue
 * @entry: work completion entry to add
 * @sig: true if @entry is a solicitated entry
 *
 * This may be called with qp->s_lock held.
 */
void qib_cq_enter(struct qib_cq *cq, struct ib_wc *entry, int solicited)
{
        struct qib_cq_wc *wc;
        unsigned long flags;
        u32 head;
        u32 next;

        spin_lock_irqsave(&cq->lock, flags);

        /*
         * Note that the head pointer might be writable by user processes.
         * Take care to verify it is a sane value.
         */
        wc = cq->queue;
        head = wc->head;
        if (head >= (unsigned) cq->ibcq.cqe) {
                head = cq->ibcq.cqe;
                next = 0;
        } else
                next = head + 1;
        if (unlikely(next == wc->tail)) {
                spin_unlock_irqrestore(&cq->lock, flags);
                if (cq->ibcq.event_handler) {
                        struct ib_event ev;

                        ev.device = cq->ibcq.device;
                        ev.element.cq = &cq->ibcq;
                        ev.event = IB_EVENT_CQ_ERR;
                        cq->ibcq.event_handler(&ev, cq->ibcq.cq_context);
                }
                return;
        }
        if (cq->ip) {
                wc->uqueue[head].wr_id = entry->wr_id;
                wc->uqueue[head].status = entry->status;
                wc->uqueue[head].opcode = entry->opcode;
                wc->uqueue[head].vendor_err = entry->vendor_err;
                wc->uqueue[head].byte_len = entry->byte_len;
                wc->uqueue[head].ex.imm_data =
                        (__u32 __force)entry->ex.imm_data;
                wc->uqueue[head].qp_num = entry->qp->qp_num;
                wc->uqueue[head].src_qp = entry->src_qp;
                wc->uqueue[head].wc_flags = entry->wc_flags;
                wc->uqueue[head].pkey_index = entry->pkey_index;
                wc->uqueue[head].slid = entry->slid;
                wc->uqueue[head].sl = entry->sl;
                wc->uqueue[head].dlid_path_bits = entry->dlid_path_bits;
                wc->uqueue[head].port_num = entry->port_num;
                /* Make sure entry is written before the head index. */
                smp_wmb();
        } else
                wc->kqueue[head] = *entry;
        wc->head = next;

        if (cq->notify == IB_CQ_NEXT_COMP ||
            (cq->notify == IB_CQ_SOLICITED &&
             (solicited || entry->status != IB_WC_SUCCESS))) {
                struct kthread_worker *worker;
                /*
                 * This will cause send_complete() to be called in
                 * another thread.
                 */
                smp_rmb();
                worker = cq->dd->worker;
                if (likely(worker)) {
                        cq->notify = IB_CQ_NONE;
                        cq->triggered++;
                        queue_kthread_work(worker, &cq->comptask);
                }
        }

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

/**
 * qib_poll_cq - poll for work completion entries
 * @ibcq: the completion queue to poll
 * @num_entries: the maximum number of entries to return
 * @entry: pointer to array where work completions are placed
 *
 * Returns the number of completion entries polled.
 *
 * This may be called from interrupt context.  Also called by ib_poll_cq()
 * in the generic verbs code.
 */
int qib_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
{
        struct qib_cq *cq = to_icq(ibcq);
        struct qib_cq_wc *wc;
        unsigned long flags;
        int npolled;
        u32 tail;

        /* The kernel can only poll a kernel completion queue */
        if (cq->ip) {
                npolled = -EINVAL;
                goto bail;
        }

        spin_lock_irqsave(&cq->lock, flags);

        wc = cq->queue;
        tail = wc->tail;
        if (tail > (u32) cq->ibcq.cqe)
                tail = (u32) cq->ibcq.cqe;
        for (npolled = 0; npolled < num_entries; ++npolled, ++entry) {
                if (tail == wc->head)
                        break;
                /* The kernel doesn't need a RMB since it has the lock. */
                *entry = wc->kqueue[tail];
                if (tail >= cq->ibcq.cqe)
                        tail = 0;
                else
                        tail++;
        }
        wc->tail = tail;

        spin_unlock_irqrestore(&cq->lock, flags);

bail:
        return npolled;
}

static void send_complete(struct kthread_work *work)
{
        struct qib_cq *cq = container_of(work, struct qib_cq, comptask);

        /*
         * The completion handler will most likely rearm the notification
         * and poll for all pending entries.  If a new completion entry
         * is added while we are in this routine, queue_work()
         * won't call us again until we return so we check triggered to
         * see if we need to call the handler again.
         */
        for (;;) {
                u8 triggered = cq->triggered;

                /*
                 * IPoIB connected mode assumes the callback is from a
                 * soft IRQ. We simulate this by blocking "bottom halves".
                 * See the implementation for ipoib_cm_handle_tx_wc(),
                 * netif_tx_lock_bh() and netif_tx_lock().
                 */
                local_bh_disable();
                cq->ibcq.comp_handler(&cq->ibcq, cq->ibcq.cq_context);
                local_bh_enable();

                if (cq->triggered == triggered)
                        return;
        }
}

/**
 * qib_create_cq - create a completion queue
 * @ibdev: the device this completion queue is attached to
 * @entries: the minimum size of the completion queue
 * @context: unused by the QLogic_IB driver
 * @udata: user data for libibverbs.so
 *
 * Returns a pointer to the completion queue or negative errno values
 * for failure.
 *
 * Called by ib_create_cq() in the generic verbs code.
 */
struct ib_cq *qib_create_cq(struct ib_device *ibdev, int entries,
                            int comp_vector, struct ib_ucontext *context,
                            struct ib_udata *udata)
{
        struct qib_ibdev *dev = to_idev(ibdev);
        struct qib_cq *cq;
        struct qib_cq_wc *wc;
        struct ib_cq *ret;
        u32 sz;

        if (entries < 1 || entries > ib_qib_max_cqes) {
                ret = ERR_PTR(-EINVAL);
                goto done;
        }

        /* Allocate the completion queue structure. */
        cq = kmalloc(sizeof(*cq), GFP_KERNEL);
        if (!cq) {
                ret = ERR_PTR(-ENOMEM);
                goto done;
        }

        /*
         * Allocate the completion queue entries and head/tail pointers.
         * This is allocated separately so that it can be resized and
         * also mapped into user space.
         * We need to use vmalloc() in order to support mmap and large
         * numbers of entries.
         */
        sz = sizeof(*wc);
        if (udata && udata->outlen >= sizeof(__u64))
                sz += sizeof(struct ib_uverbs_wc) * (entries + 1);
        else
                sz += sizeof(struct ib_wc) * (entries + 1);
        wc = vmalloc_user(sz);
        if (!wc) {
                ret = ERR_PTR(-ENOMEM);
                goto bail_cq;
        }

        /*
         * Return the address of the WC as the offset to mmap.
         * See qib_mmap() for details.
         */
        if (udata && udata->outlen >= sizeof(__u64)) {
                int err;

                cq->ip = qib_create_mmap_info(dev, sz, context, wc);
                if (!cq->ip) {
                        ret = ERR_PTR(-ENOMEM);
                        goto bail_wc;
                }

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

        spin_lock(&dev->n_cqs_lock);
        if (dev->n_cqs_allocated == ib_qib_max_cqs) {
                spin_unlock(&dev->n_cqs_lock);
                ret = ERR_PTR(-ENOMEM);
                goto bail_ip;
        }

        dev->n_cqs_allocated++;
        spin_unlock(&dev->n_cqs_lock);

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

        /*
         * ib_create_cq() will initialize cq->ibcq except for cq->ibcq.cqe.
         * The number of entries should be >= the number requested or return
         * an error.
         */
        cq->dd = dd_from_dev(dev);
        cq->ibcq.cqe = entries;
        cq->notify = IB_CQ_NONE;
        cq->triggered = 0;
        spin_lock_init(&cq->lock);
        init_kthread_work(&cq->comptask, send_complete);
        wc->head = 0;
        wc->tail = 0;
        cq->queue = wc;

        ret = &cq->ibcq;

        goto done;

bail_ip:
        kfree(cq->ip);
bail_wc:
        vfree(wc);
bail_cq:
        kfree(cq);
done:
        return ret;
}

/**
 * qib_destroy_cq - destroy a completion queue
 * @ibcq: the completion queue to destroy.
 *
 * Returns 0 for success.
 *
 * Called by ib_destroy_cq() in the generic verbs code.
 */
int qib_destroy_cq(struct ib_cq *ibcq)
{
        struct qib_ibdev *dev = to_idev(ibcq->device);
        struct qib_cq *cq = to_icq(ibcq);

        flush_kthread_work(&cq->comptask);
        spin_lock(&dev->n_cqs_lock);
        dev->n_cqs_allocated--;
        spin_unlock(&dev->n_cqs_lock);
        if (cq->ip)
                kref_put(&cq->ip->ref, qib_release_mmap_info);
        else
                vfree(cq->queue);
        kfree(cq);

        return 0;
}

/**
 * qib_req_notify_cq - change the notification type for a completion queue
 * @ibcq: the completion queue
 * @notify_flags: the type of notification to request
 *
 * Returns 0 for success.
 *
 * This may be called from interrupt context.  Also called by
 * ib_req_notify_cq() in the generic verbs code.
 */
int qib_req_notify_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags notify_flags)
{
        struct qib_cq *cq = to_icq(ibcq);
        unsigned long flags;
        int ret = 0;

        spin_lock_irqsave(&cq->lock, flags);
        /*
         * Don't change IB_CQ_NEXT_COMP to IB_CQ_SOLICITED but allow
         * any other transitions (see C11-31 and C11-32 in ch. 11.4.2.2).
         */
        if (cq->notify != IB_CQ_NEXT_COMP)
                cq->notify = notify_flags & IB_CQ_SOLICITED_MASK;

        if ((notify_flags & IB_CQ_REPORT_MISSED_EVENTS) &&
            cq->queue->head != cq->queue->tail)
                ret = 1;

        spin_unlock_irqrestore(&cq->lock, flags);

        return ret;
}

/**
 * qib_resize_cq - change the size of the CQ
 * @ibcq: the completion queue
 *
 * Returns 0 for success.
 */
int qib_resize_cq(struct ib_cq *ibcq, int cqe, struct ib_udata *udata)
{
        struct qib_cq *cq = to_icq(ibcq);
        struct qib_cq_wc *old_wc;
        struct qib_cq_wc *wc;
        u32 head, tail, n;
        int ret;
        u32 sz;

        if (cqe < 1 || cqe > ib_qib_max_cqes) {
                ret = -EINVAL;
                goto bail;
        }

        /*
         * Need to use vmalloc() if we want to support large #s of entries.
         */
        sz = sizeof(*wc);
        if (udata && udata->outlen >= sizeof(__u64))
                sz += sizeof(struct ib_uverbs_wc) * (cqe + 1);
        else
                sz += sizeof(struct ib_wc) * (cqe + 1);
        wc = vmalloc_user(sz);
        if (!wc) {
                ret = -ENOMEM;
                goto bail;
        }

        /* Check that we can write the offset to mmap. */
        if (udata && udata->outlen >= sizeof(__u64)) {
                __u64 offset = 0;

                ret = ib_copy_to_udata(udata, &offset, sizeof(offset));
                if (ret)
                        goto bail_free;
        }

        spin_lock_irq(&cq->lock);
        /*
         * Make sure head and tail are sane since they
         * might be user writable.
         */
        old_wc = cq->queue;
        head = old_wc->head;
        if (head > (u32) cq->ibcq.cqe)
                head = (u32) cq->ibcq.cqe;
        tail = old_wc->tail;
        if (tail > (u32) cq->ibcq.cqe)
                tail = (u32) cq->ibcq.cqe;
        if (head < tail)
                n = cq->ibcq.cqe + 1 + head - tail;
        else
                n = head - tail;
        if (unlikely((u32)cqe < n)) {
                ret = -EINVAL;
                goto bail_unlock;
        }
        for (n = 0; tail != head; n++) {
                if (cq->ip)
                        wc->uqueue[n] = old_wc->uqueue[tail];
                else
                        wc->kqueue[n] = old_wc->kqueue[tail];
                if (tail == (u32) cq->ibcq.cqe)
                        tail = 0;
                else
                        tail++;
        }
        cq->ibcq.cqe = cqe;
        wc->head = n;
        wc->tail = 0;
        cq->queue = wc;
        spin_unlock_irq(&cq->lock);

        vfree(old_wc);

        if (cq->ip) {
                struct qib_ibdev *dev = to_idev(ibcq->device);
                struct qib_mmap_info *ip = cq->ip;

                qib_update_mmap_info(dev, ip, sz, wc);

                /*
                 * Return the offset to mmap.
                 * See qib_mmap() for details.
                 */
                if (udata && udata->outlen >= sizeof(__u64)) {
                        ret = ib_copy_to_udata(udata, &ip->offset,
                                               sizeof(ip->offset));
                        if (ret)
                                goto bail;
                }

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

        ret = 0;
        goto bail;

bail_unlock:
        spin_unlock_irq(&cq->lock);
bail_free:
        vfree(wc);
bail:
        return ret;
}

int qib_cq_init(struct qib_devdata *dd)
{
        int ret = 0;
        int cpu;
        struct task_struct *task;

        if (dd->worker)
                return 0;
        dd->worker = kzalloc(sizeof(*dd->worker), GFP_KERNEL);
        if (!dd->worker)
                return -ENOMEM;
        init_kthread_worker(dd->worker);
        task = kthread_create_on_node(
                kthread_worker_fn,
                dd->worker,
                dd->assigned_node_id,
                "qib_cq%d", dd->unit);
        if (IS_ERR(task))
                goto task_fail;
        cpu = cpumask_first(cpumask_of_node(dd->assigned_node_id));
        kthread_bind(task, cpu);
        wake_up_process(task);
out:
        return ret;
task_fail:
        ret = PTR_ERR(task);
        kfree(dd->worker);
        dd->worker = NULL;
        goto out;
}

void qib_cq_exit(struct qib_devdata *dd)
{
        struct kthread_worker *worker;

        worker = dd->worker;
        if (!worker)
                return;
        /* blocks future queuing from send_complete() */
        dd->worker = NULL;
        smp_wmb();
        flush_kthread_worker(worker);
        kthread_stop(worker->task);
        kfree(worker);
}