/*
 * Copyright (c) 2012-2016 VMware, Inc.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of EITHER the GNU General Public License
 * version 2 as published by the Free Software Foundation or the BSD
 * 2-Clause License. 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 version 2 for more details at
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program available in the file COPYING in the main
 * directory of this source tree.
 *
 * The BSD 2-Clause License
 *
 *     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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <asm/page.h>
#include <linux/io.h>
#include <linux/wait.h>
#include <rdma/ib_addr.h>
#include <rdma/ib_smi.h>
#include <rdma/ib_user_verbs.h>

#include "pvrdma.h"

/**
 * pvrdma_req_notify_cq - request notification for a completion queue
 * @ibcq: the completion queue
 * @notify_flags: notification flags
 *
 * @return: 0 for success.
 */
int pvrdma_req_notify_cq(struct ib_cq *ibcq,
                         enum ib_cq_notify_flags notify_flags)
{
        struct pvrdma_dev *dev = to_vdev(ibcq->device);
        struct pvrdma_cq *cq = to_vcq(ibcq);
        u32 val = cq->cq_handle;
        unsigned long flags;
        int has_data = 0;

        val |= (notify_flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
                PVRDMA_UAR_CQ_ARM_SOL : PVRDMA_UAR_CQ_ARM;

        spin_lock_irqsave(&cq->cq_lock, flags);

        pvrdma_write_uar_cq(dev, val);

        if (notify_flags & IB_CQ_REPORT_MISSED_EVENTS) {
                unsigned int head;

                has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
                                                    cq->ibcq.cqe, &head);
                if (unlikely(has_data == PVRDMA_INVALID_IDX))
                        dev_err(&dev->pdev->dev, "CQ ring state invalid\n");
        }

        spin_unlock_irqrestore(&cq->cq_lock, flags);

        return has_data;
}

/**
 * pvrdma_create_cq - create completion queue
 * @ibdev: the device
 * @attr: completion queue attributes
 * @context: user context
 * @udata: user data
 *
 * @return: ib_cq completion queue pointer on success,
 *          otherwise returns negative errno.
 */
struct ib_cq *pvrdma_create_cq(struct ib_device *ibdev,
                               const struct ib_cq_init_attr *attr,
                               struct ib_ucontext *context,
                               struct ib_udata *udata)
{
        int entries = attr->cqe;
        struct pvrdma_dev *dev = to_vdev(ibdev);
        struct pvrdma_cq *cq;
        int ret;
        int npages;
        unsigned long flags;
        union pvrdma_cmd_req req;
        union pvrdma_cmd_resp rsp;
        struct pvrdma_cmd_create_cq *cmd = &req.create_cq;
        struct pvrdma_cmd_create_cq_resp *resp = &rsp.create_cq_resp;
        struct pvrdma_create_cq_resp cq_resp = {0};
        struct pvrdma_create_cq ucmd;

        BUILD_BUG_ON(sizeof(struct pvrdma_cqe) != 64);

        entries = roundup_pow_of_two(entries);
        if (entries < 1 || entries > dev->dsr->caps.max_cqe)
                return ERR_PTR(-EINVAL);

        if (!atomic_add_unless(&dev->num_cqs, 1, dev->dsr->caps.max_cq))
                return ERR_PTR(-ENOMEM);

        cq = kzalloc(sizeof(*cq), GFP_KERNEL);
        if (!cq) {
                atomic_dec(&dev->num_cqs);
                return ERR_PTR(-ENOMEM);
        }

        cq->ibcq.cqe = entries;
        cq->is_kernel = !context;

        if (!cq->is_kernel) {
                if (ib_copy_from_udata(&ucmd, udata, sizeof(ucmd))) {
                        ret = -EFAULT;
                        goto err_cq;
                }

                cq->umem = ib_umem_get(context, ucmd.buf_addr, ucmd.buf_size,
                                       IB_ACCESS_LOCAL_WRITE, 1);
                if (IS_ERR(cq->umem)) {
                        ret = PTR_ERR(cq->umem);
                        goto err_cq;
                }

                npages = ib_umem_page_count(cq->umem);
        } else {
                /* One extra page for shared ring state */
                npages = 1 + (entries * sizeof(struct pvrdma_cqe) +
                              PAGE_SIZE - 1) / PAGE_SIZE;

                /* Skip header page. */
                cq->offset = PAGE_SIZE;
        }

        if (npages < 0 || npages > PVRDMA_PAGE_DIR_MAX_PAGES) {
                dev_warn(&dev->pdev->dev,
                         "overflow pages in completion queue\n");
                ret = -EINVAL;
                goto err_umem;
        }

        ret = pvrdma_page_dir_init(dev, &cq->pdir, npages, cq->is_kernel);
        if (ret) {
                dev_warn(&dev->pdev->dev,
                         "could not allocate page directory\n");
                goto err_umem;
        }

        /* Ring state is always the first page. Set in library for user cq. */
        if (cq->is_kernel)
                cq->ring_state = cq->pdir.pages[0];
        else
                pvrdma_page_dir_insert_umem(&cq->pdir, cq->umem, 0);

        refcount_set(&cq->refcnt, 1);
        init_completion(&cq->free);
        spin_lock_init(&cq->cq_lock);

        memset(cmd, 0, sizeof(*cmd));
        cmd->hdr.cmd = PVRDMA_CMD_CREATE_CQ;
        cmd->nchunks = npages;
        cmd->ctx_handle = (context) ?
                (u64)to_vucontext(context)->ctx_handle : 0;
        cmd->cqe = entries;
        cmd->pdir_dma = cq->pdir.dir_dma;
        ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_CQ_RESP);
        if (ret < 0) {
                dev_warn(&dev->pdev->dev,
                         "could not create completion queue, error: %d\n", ret);
                goto err_page_dir;
        }

        cq->ibcq.cqe = resp->cqe;
        cq->cq_handle = resp->cq_handle;
        cq_resp.cqn = resp->cq_handle;
        spin_lock_irqsave(&dev->cq_tbl_lock, flags);
        dev->cq_tbl[cq->cq_handle % dev->dsr->caps.max_cq] = cq;
        spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);

        if (!cq->is_kernel) {
                cq->uar = &(to_vucontext(context)->uar);

                /* Copy udata back. */
                if (ib_copy_to_udata(udata, &cq_resp, sizeof(cq_resp))) {
                        dev_warn(&dev->pdev->dev,
                                 "failed to copy back udata\n");
                        pvrdma_destroy_cq(&cq->ibcq);
                        return ERR_PTR(-EINVAL);
                }
        }

        return &cq->ibcq;

err_page_dir:
        pvrdma_page_dir_cleanup(dev, &cq->pdir);
err_umem:
        if (!cq->is_kernel)
                ib_umem_release(cq->umem);
err_cq:
        atomic_dec(&dev->num_cqs);
        kfree(cq);

        return ERR_PTR(ret);
}

static void pvrdma_free_cq(struct pvrdma_dev *dev, struct pvrdma_cq *cq)
{
        if (refcount_dec_and_test(&cq->refcnt))
                complete(&cq->free);
        wait_for_completion(&cq->free);

        if (!cq->is_kernel)
                ib_umem_release(cq->umem);

        pvrdma_page_dir_cleanup(dev, &cq->pdir);
        kfree(cq);
}

/**
 * pvrdma_destroy_cq - destroy completion queue
 * @cq: the completion queue to destroy.
 *
 * @return: 0 for success.
 */
int pvrdma_destroy_cq(struct ib_cq *cq)
{
        struct pvrdma_cq *vcq = to_vcq(cq);
        union pvrdma_cmd_req req;
        struct pvrdma_cmd_destroy_cq *cmd = &req.destroy_cq;
        struct pvrdma_dev *dev = to_vdev(cq->device);
        unsigned long flags;
        int ret;

        memset(cmd, 0, sizeof(*cmd));
        cmd->hdr.cmd = PVRDMA_CMD_DESTROY_CQ;
        cmd->cq_handle = vcq->cq_handle;

        ret = pvrdma_cmd_post(dev, &req, NULL, 0);
        if (ret < 0)
                dev_warn(&dev->pdev->dev,
                         "could not destroy completion queue, error: %d\n",
                         ret);

        /* free cq's resources */
        spin_lock_irqsave(&dev->cq_tbl_lock, flags);
        dev->cq_tbl[vcq->cq_handle] = NULL;
        spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);

        pvrdma_free_cq(dev, vcq);
        atomic_dec(&dev->num_cqs);

        return ret;
}

static inline struct pvrdma_cqe *get_cqe(struct pvrdma_cq *cq, int i)
{
        return (struct pvrdma_cqe *)pvrdma_page_dir_get_ptr(
                                        &cq->pdir,
                                        cq->offset +
                                        sizeof(struct pvrdma_cqe) * i);
}

void _pvrdma_flush_cqe(struct pvrdma_qp *qp, struct pvrdma_cq *cq)
{
        unsigned int head;
        int has_data;

        if (!cq->is_kernel)
                return;

        /* Lock held */
        has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
                                            cq->ibcq.cqe, &head);
        if (unlikely(has_data > 0)) {
                int items;
                int curr;
                int tail = pvrdma_idx(&cq->ring_state->rx.prod_tail,
                                      cq->ibcq.cqe);
                struct pvrdma_cqe *cqe;
                struct pvrdma_cqe *curr_cqe;

                items = (tail > head) ? (tail - head) :
                        (cq->ibcq.cqe - head + tail);
                curr = --tail;
                while (items-- > 0) {
                        if (curr < 0)
                                curr = cq->ibcq.cqe - 1;
                        if (tail < 0)
                                tail = cq->ibcq.cqe - 1;
                        curr_cqe = get_cqe(cq, curr);
                        if ((curr_cqe->qp & 0xFFFF) != qp->qp_handle) {
                                if (curr != tail) {
                                        cqe = get_cqe(cq, tail);
                                        *cqe = *curr_cqe;
                                }
                                tail--;
                        } else {
                                pvrdma_idx_ring_inc(
                                        &cq->ring_state->rx.cons_head,
                                        cq->ibcq.cqe);
                        }
                        curr--;
                }
        }
}

static int pvrdma_poll_one(struct pvrdma_cq *cq, struct pvrdma_qp **cur_qp,
                           struct ib_wc *wc)
{
        struct pvrdma_dev *dev = to_vdev(cq->ibcq.device);
        int has_data;
        unsigned int head;
        bool tried = false;
        struct pvrdma_cqe *cqe;

retry:
        has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
                                            cq->ibcq.cqe, &head);
        if (has_data == 0) {
                if (tried)
                        return -EAGAIN;

                pvrdma_write_uar_cq(dev, cq->cq_handle | PVRDMA_UAR_CQ_POLL);

                tried = true;
                goto retry;
        } else if (has_data == PVRDMA_INVALID_IDX) {
                dev_err(&dev->pdev->dev, "CQ ring state invalid\n");
                return -EAGAIN;
        }

        cqe = get_cqe(cq, head);

        /* Ensure cqe is valid. */
        rmb();
        if (dev->qp_tbl[cqe->qp & 0xffff])
                *cur_qp = (struct pvrdma_qp *)dev->qp_tbl[cqe->qp & 0xffff];
        else
                return -EAGAIN;

        wc->opcode = pvrdma_wc_opcode_to_ib(cqe->opcode);
        wc->status = pvrdma_wc_status_to_ib(cqe->status);
        wc->wr_id = cqe->wr_id;
        wc->qp = &(*cur_qp)->ibqp;
        wc->byte_len = cqe->byte_len;
        wc->ex.imm_data = cqe->imm_data;
        wc->src_qp = cqe->src_qp;
        wc->wc_flags = pvrdma_wc_flags_to_ib(cqe->wc_flags);
        wc->pkey_index = cqe->pkey_index;
        wc->slid = cqe->slid;
        wc->sl = cqe->sl;
        wc->dlid_path_bits = cqe->dlid_path_bits;
        wc->port_num = cqe->port_num;
        wc->vendor_err = cqe->vendor_err;
        wc->network_hdr_type = cqe->network_hdr_type;

        /* Update shared ring state */
        pvrdma_idx_ring_inc(&cq->ring_state->rx.cons_head, cq->ibcq.cqe);

        return 0;
}

/**
 * pvrdma_poll_cq - poll for work completion queue entries
 * @ibcq: completion queue
 * @num_entries: the maximum number of entries
 * @entry: pointer to work completion array
 *
 * @return: number of polled completion entries
 */
int pvrdma_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc)
{
        struct pvrdma_cq *cq = to_vcq(ibcq);
        struct pvrdma_qp *cur_qp = NULL;
        unsigned long flags;
        int npolled;

        if (num_entries < 1 || wc == NULL)
                return 0;

        spin_lock_irqsave(&cq->cq_lock, flags);
        for (npolled = 0; npolled < num_entries; ++npolled) {
                if (pvrdma_poll_one(cq, &cur_qp, wc + npolled))
                        break;
        }

        spin_unlock_irqrestore(&cq->cq_lock, flags);

        /* Ensure we do not return errors from poll_cq */
        return npolled;
}